The authors have no acknowledgements.

These protocols follow the guidelines of our institution&#39;s human research ethics committee.
1. Conventional Corneal Collagen CXL (C-CXL)
1. Preparation of the Patient
<ol>
	<li>5 days before the surgery, put 1% pilocarpine drops twice a day in the treated eye.</li>
	<li>In the operating room, in aseptic conditions, lie the patient on his/her back.</li>
	<li>Administer topical anesthesia such as oxybuprocaine 0.4%.</li>
	<li>Clean the eye and the skin around the eye with iodine antiseptic twice.</li>
	<li>Use a lid speculum to keep the eye open.</li>
</ol>
2. Epithelial Removal
<ol>
	<li>Mark the central 9.0 mm of the cornea with a circle corneal marker.</li>
	<li>Remove the central 7.0 to 9.0 mm of corneal epithelium by mechanical debridement using a blunt spatula.</li>
</ol>
3. Riboflavin Application
<ol>
	<li>Apply 0.1% riboflavin with 20% Dextran on the cornea every min for 20 min.</li>
</ol>
4. UVA Irradiation
<ol>
	<li>Irradiate the cornea with a 370 nm wavelength UVA light at an irradiance of 3 mW/cm2 (5.4 J/cm2 surface dose) and at a 5 cm working distance for 30 min.</li>
</ol>
<img alt="Figure 1" src="/files/ftp_upload/53119/53119fig1.jpg" />
Figure 1: UVA irradiation in C-CXL. The cornea is irradiated with a 370 nm wavelength UVA light at an irradiance of 3 mW/cm2 (5.4 J/cm2 surface dose) and at a 5 cm working distance for 30 minutes. <a href="https://www.jove.com/files/ftp_upload/53119/53119fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>During irradiation, apply drops of riboflavin to the cornea every 5 min.</li>
	<li>During irradiation, add topical anesthesia (oxybuprocaine 0.4%) if necessary.</li>
</ol>
5. End of the Surgery
<ol>
	<li>Put antibiotic drops (tobramycin 0.3%) and artificial tears (hyaluronate drops 0.18%) into the operated eye.</li>
	<li>Place a soft bandage contact lens at the end of surgery until re-epithelialization is complete. Re-epithelialization usually takes 3 days.</li>
	<li>Prescribe analgesics such as paracetamol (500 mg) plus codeine (30 mg), 6 pills a day.</li>
	<li>After corneal re-epithelialization, initiate topical therapy with steroids (topical dexamethasone 1 mg/ml) and continue for 3-4 weeks. Plus, use artificial tears 4 times a day for 1 month.</li>
</ol>
2. Accelerated Corneal Collagen CXL (A-CXL)
1. Preparation of the Patient
<ol>
	<li>5 days before the surgery, put 1% pilocarpine drops twice a day in the treated eye.</li>
	<li>In the operating room, in aseptic conditions, lie the patient on his/her back.</li>
	<li>Administer topical anesthesia such as oxybuprocaine 0.4%.</li>
	<li>Clean the eye and the skin around the eye with iodine antiseptic twice.</li>
	<li>Use a lid speculum to keep the eye open.</li>
</ol>
2. Epithelial Removal
<ol>
	<li>Mark the central 9.0 mm of the cornea with a circle corneal marker</li>
	<li>Remove the central 7.0 to 9.0 mm of corneal epithelium by mechanical debridement using a blunt spatula.</li>
</ol>
3. Riboflavin Application
<ol>
	<li>Apply 0.1% riboflavin without Dextran on the cornea every 2 min for 10 min.</li>
</ol>
4. UVA Irradiation
<ol>
	<li>Irradiate the cornea with a 370 nm wavelength UVA light at an irradiance of 30 mW/cm2 (5.4 J/cm2 surface dose) and at a 5 cm working distance for 3 min.</li>
	<li>During the irradiation, add topical anesthesia (oxybuproca&#38;#239;ne 0.4%) if necessary.</li>
</ol>
5. End of the Surgery
<ol>
	<li>Place antibiotic drops (tobramycin 0.3%) and artificial tears (hyaluronate drops 0.18%) into the operated eye.</li>
	<li>Place a soft bandage contact lens at the end of surgery until re-epithelialization is complete. Re-epithelialization usually takes 3 days.</li>
	<li>Prescribe analgesics such as paracetamol (500 mg) plus codeine (30 mg), 6 pills a day.</li>
	<li>After corneal re-epithelialization, initiate topical therapy with steroids (topical dexamethasone 1 mg/ml) and continue for 3-4 weeks. Plus, use artificial tears 4 times a day for 1 month.</li>
</ol>
3. Iontophoresis (I-CXL)
1. Preparation of the Patient
<ol>
	<li>5 days before the surgery, put 1% pilocarpine drops twice a day in the treated eye.</li>
	<li>In the operating room, in aseptic conditions, lie the patient on his/her back.</li>
	<li>Administer topical anesthesia such as oxybuprocaine 0.4%.</li>
	<li>Clean the eye and the skin around the eye with iodine antiseptic twice.</li>
	<li>Use a lid speculum to keep the eye open.</li>
</ol>
2. Position the Iontophoresis Device.
<ol>
	<li>Apply the sticky passive electrode on the forehead under the operative field.</li>
	<li>Apply the active electrode, a suction ring, to the open eye. Center the suction ring on the periphery of the cornea before releasing the suction.</li>
</ol>
<img alt="Figure 2" src="/files/ftp_upload/53119/53119fig2.jpg" />
Figure 2. Iontophoresis device. The passive electrode is applied on the forehead under the operative field and the active electrode, a suction ring, is applied to the open eye. <a href="https://www.jove.com/files/ftp_upload/53119/53119fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
3. Riboflavin Application
<ol>
	<li>Fill the suction ring with hypoosmolar 0.1% riboflavin without Dextran.</li>
</ol>
<img alt="Figure 3" src="/files/ftp_upload/53119/53119fig3.jpg" />
Figure 3. Riboflavin application in I-CXL. The suction ring is filled with hypoosmolar 0.1% riboflavine without Dextran. <a href="https://www.jove.com/files/ftp_upload/53119/53119fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>Start the electrical current at 0.2 mA and gradually increase to 1.0 mA for a total iontophoresis time of 5 min (Figure 4).</li>
</ol>
<img alt="Figure 4" src="/files/ftp_upload/53119/53119fig4.jpg" />
Figure 4. Iontophoresis device for riboflavin penetration. The electrical current is initially 0.2 mA and gradually increased to 1.0 mA. Total iontophoresis time is 5 minutes. <a href="https://www.jove.com/files/ftp_upload/53119/53119fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
4. UVA Irradiation
<ol>
	<li>Irradiate the cornea with a 370 nm wavelength UVA light at an irradiance of 10 mW/cm2 (5.4 J/cm2 surface dose) and at a 5 cm working distance for 9 min.</li>
	<li>During the irradiation, add topical anesthesia (oxybuproca&#38;#239;ne 0.4%) if necessary.</li>
</ol>
5. End of the Surgery
<ol>
	<li>Place antibiotic drops (tobramycin 0.3%) and artificial tears (hyaluronate drops 0.18%) into the operated eye.</li>
	<li>Prescribe analgesics such as paracetamol (500 mg) plus codeine (30 mg), 6 pills a day.</li>
	<li>After surgery, initiate topical therapy with steroids (topical dexamethasone 1mg/ml) and continue for 3-4 weeks. Plus, use artificial tears 4 times a day for 1 month.</li>
</ol>

<ol>
	<li>Rabinowitz, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Keratoconus.">Keratoconus.</a> Surv Ophthalmol. 42 (4), 297-319 (1998).</li><li>Tuori, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+immunohistochemical+composition+of+corneal+basement+membrane+in+keratoconus.">The immunohistochemical composition of corneal basement membrane in keratoconus.</a> Curr Eye Res. 16 (8), 792-801 (1997).</li><li>Wollensak, G., Spoerl, E., Seiler, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Riboflavin/ultraviolet-A-induced+collagen+cross-linking+for+the+treatment+of+keratoconus.">Riboflavin/ultraviolet-A-induced collagen cross-linking for the treatment of keratoconus.</a> Am J Ophthalmol. 135 (5), 620-627 (2003).</li><li>Raiskup-Wolf, F., Hoyer, A., Spoerl, E., Pillunat, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen+cross-linking+with+riboflavin+and+ultraviolet-A+light+in+keratoconus:+long-term+results.">Collagen cross-linking with riboflavin and ultraviolet-A light in keratoconus: long-term results.</a> J Cataract Refract Surg. 34 (5), 796-801 (2008).</li><li>Vinciguerra, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=topographic,+tomographic,+and+aberrometric+analysis+of+keratoconic+eyes+undergoing+corneal+cross-linking.">topographic, tomographic, and aberrometric analysis of keratoconic eyes undergoing corneal cross-linking.</a> Ophthalmology. 116 (3), 369-378 (2009).</li><li>Caporossi, A., Mazzotta, C., Baiocchi, S., Caporossi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+results+of+riboflavin+ultraviolet-A+corneal+collagen+cross-linking+for+keratoconus+in+Italy:+the+Siena+eye+cross+study.">Long-term results of riboflavin ultraviolet-A corneal collagen cross-linking for keratoconus in Italy: the Siena eye cross study.</a> Am J Ophthalmol. 149 (4), 585-593 (2010).</li><li>Greenstein, S. A., Fry, K. L., Hersh, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+topography+indices+after+corneal+collagen+cross-linking+for+keratoconus+and+corneal+ectasia:+one-year+results.">Corneal topography indices after corneal collagen cross-linking for keratoconus and corneal ectasia: one-year results.</a> J Cataract Refract Surg. 37 (7), 1282-1290 (2011).</li><li>Ghanem, R. C., Santhiago, M. R., Berti, T., Netto, M. V., Ghanem, V. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topographic+corneal+wavefront,+and+refractive+outcomes+2+years+after+collagen+cross-linking+for+progressive+keratoconus.">Topographic corneal wavefront, and refractive outcomes 2 years after collagen cross-linking for progressive keratoconus.</a> Cornea. 33 (1), 43-48 (2014).</li><li>Koller, T., Mrochen, M., Seiler, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complication+and+failure+rates+after+corneal+cross-linking.">Complication and failure rates after corneal cross-linking.</a> J Cataract Refract Surg. 35 (8), 1358-1362 (2009).</li><li>Rocha, K. M., Ramos-Esteban, J. C., Qian, Y., Herekar, S., Krueger, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+study+of+riboflavin-UVA+cross-linking+and+&#8220;flash-linking&#8221;+using+surface+wave+elastometry.">Comparative study of riboflavin-UVA cross-linking and &#8220;flash-linking&#8221; using surface wave elastometry.</a> J Refract Surg. 24 (7), 748-751 (2008).</li><li>Caporossi, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transepithelial+corneal+collagen+crosslinking+for+progressive+keratoconus:+24-month+clinical+results.">Transepithelial corneal collagen crosslinking for progressive keratoconus: 24-month clinical results.</a> J Cataract Refract Surg. 39 (8), 1157-1163 (2013).</li><li>Bikbova, G., Bikbov, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transepithelial+corneal+collagen+cross-linking+by+iontophoresis+of+riboflavin.">Transepithelial corneal collagen cross-linking by iontophoresis of riboflavin.</a> Acta Ophthalmol. 92 (1), 30-34 (2014).</li><li>Efron, N., Hollingsworth, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+perspectives+on+keratoconus+as+revealed+by+corneal+confocal+microscopy.">New perspectives on keratoconus as revealed by corneal confocal microscopy.</a> Clin Exp Optom. 91 (1), 34-55 (2008).</li><li>Patel, D. V., McGhee, C. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+the+corneal+sub-basal+nerve+plexus+in+keratoconus+by+in+vivo+laser+scanning+confocal+microscopy.">Mapping the corneal sub-basal nerve plexus in keratoconus by in vivo laser scanning confocal microscopy.</a> Invest Ophthalmol Vis Sci. 47 (4), 1348-1351 (2006).</li><li>Ku, J. Y., Niederer, R. L., Patel, D. V., Sherwin, T., McGhee, C. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+scanning+in+vivo+confocal+analysis+of+keratocyte+density+in+keratoconus.">Laser scanning in vivo confocal analysis of keratocyte density in keratoconus.</a> Ophthalmology. 115 (5), 845-850 (2008).</li><li>Mazzotta, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+healing+after+riboflavin+ultraviolet-A+collagen+cross-linking+determined+by+confocal+laser+scanning+microscopy+in+vivo:+early+and+late+modifications.">Corneal healing after riboflavin ultraviolet-A collagen cross-linking determined by confocal laser scanning microscopy in vivo: early and late modifications.</a> Am J Ophthalmol. 146 (4), 527-533 (2008).</li><li>Seiler, T., Hafezi, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+cross-linking-induced+stromal+demarcation+line.">Corneal cross-linking-induced stromal demarcation line.</a> Cornea. 25 (9), 1057-1059 (2006).</li><li>Doors, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+anterior+segment+optical+coherence+tomography+to+study+corneal+changes+after+collagen+cross-linking.">Use of anterior segment optical coherence tomography to study corneal changes after collagen cross-linking.</a> Am J Ophthalmol. 148 (6), 844-851 (2009).</li><li>Mazzotta, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treatment+of+progressive+keratoconus+by+riboflavin-UVA-induced+cross-linking+of+corneal+collagen:+ultrastructural+analysis+by+Heidelberg+Retinal+Tomograph+II+in+vivo+confocal+microscopy+in+humans.">Treatment of progressive keratoconus by riboflavin-UVA-induced cross-linking of corneal collagen: ultrastructural analysis by Heidelberg Retinal Tomograph II in vivo confocal microscopy in humans.</a> Cornea. 26 (4), 390-397 (2007).</li><li>Kymionis, G. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+of+the+corneal+collagen+cross-linking+demarcation+line+using+confocal+microscopy+and+anterior+segment+optical+coherence+tomography+in+keratoconic+patients.">Correlation of the corneal collagen cross-linking demarcation line using confocal microscopy and anterior segment optical coherence tomography in keratoconic patients.</a> Am J Ophthalmol. 157 (1), 110-115 (2014).</li><li>Yam, J. C., Chan, C. W., Cheng, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+collagen+cross-linking+demarcation+line+depth+assessed+by+Visante+OCT+After+CXL+for+keratoconus+and+corneal+ectasia.">Corneal collagen cross-linking demarcation line depth assessed by Visante OCT After CXL for keratoconus and corneal ectasia.</a> J Refract Surg. 28 (7), 475-481 (2012).</li><li>Jordan, C., Patel, D. V., Abeysekera, N., McGhee, C. .. N. .. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+confocal+microscopy+analyses+of+corneal+microstructural+changes+in+a+prospective+study+of+collagen+cross-linking+in+keratoconus.">In vivo confocal microscopy analyses of corneal microstructural changes in a prospective study of collagen cross-linking in keratoconus.</a> Ophthalmology. 121 (2), 469-474 (2014).</li><li>Touboul, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+confocal+microscopy+following+conventional,+transepithelial,+and+accelerated+corneal+collagen+cross-linking+procedures+for+keratoconus.">Corneal confocal microscopy following conventional, transepithelial, and accelerated corneal collagen cross-linking procedures for keratoconus.</a> J Refract Surg. 28 (11), 769-776 (2012).</li><li>Bouheraoua, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+coherence+tomography+and+confocal+microscopy+following+three+different+protocols+of+corneal+collagen-crosslinking+in+keratoconus.">Optical coherence tomography and confocal microscopy following three different protocols of corneal collagen-crosslinking in keratoconus.</a> Invest Ophthalmol Vis Sci. 55 (11), 7601-7609 (2014).</li><li>Hafezi, F., Mrochen, M., Iseli, H. P., Seiler, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen+crosslinking+with+ultraviolet-A+and+hypoosmolar+riboflavin+solution+in+thin+corneas.">Collagen crosslinking with ultraviolet-A and hypoosmolar riboflavin solution in thin corneas.</a> J Cataract Refract Surg. 35 (4), 621-624 (2009).</li><li>C&#305;nar, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+accelerated+and+conventional+corneal+collagen+cross-linking+for+progressive+keratoconus.">Comparison of accelerated and conventional corneal collagen cross-linking for progressive keratoconus.</a> Cutan Ocul Toxicol. 33 (3), 218-222 (2013).</li><li>Cing&#252;, A. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+corneal+endothelial+changes+following+accelerated+collagen+cross-linking+for+the+treatment+of+progressive+keratoconus.">Transient corneal endothelial changes following accelerated collagen cross-linking for the treatment of progressive keratoconus.</a> Cutan Ocul Toxicol. 33 (2), 127-131 (2013).</li><li>Spoerl, E., Mrochen, M., Sliney, D., Trokel, S., Seiler, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Safety+of+UVA-riboflavin+cross-linking+of+the+cornea.">Safety of UVA-riboflavin cross-linking of the cornea.</a> Cornea. 26 (4), 385-389 (2007).</li><li>Gokhale, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+endothelial+damage+after+collagen+cross-linking+treatment.">Corneal endothelial damage after collagen cross-linking treatment.</a> Cornea. 30 (12), 1495-1498 (2011).</li><li>Rootman, D. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacokinetics+and+safety+of+transcorneal+iontophoresis+of+tobramycin+in+the+rabbit.">Pharmacokinetics and safety of transcorneal iontophoresis of tobramycin in the rabbit.</a> Invest Ophthalmol Vis Sci. 29 (9), 1397-1401 (1998).</li><li>Vinciguerra, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transepithelial+iontophoresis+corneal+collagen+cross-linking+for+progressive+keratoconus:+initial+clinical+outcomes.">Transepithelial iontophoresis corneal collagen cross-linking for progressive keratoconus: initial clinical outcomes.</a> J Refract Surg. 30 (11), 746-753 (2014).</li><li>Caporossi, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Riboflavin-UVA-induced+corneal+collagen+cross-linking+in+pediatric+patients.">Riboflavin-UVA-induced corneal collagen cross-linking in pediatric patients.</a> Cornea. 31 (3), 227-231 (2012).</li><li>Buzzonetti, L., Petrocelli, G., Valente, P., Larossi, G., Ardia, R., Petroni, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iontophoretic+transepithelial+corneal+cross-linking+to+halt+keratoconus+in+pediatric+cases:+15-month+follow-up.">Iontophoretic transepithelial corneal cross-linking to halt keratoconus in pediatric cases: 15-month follow-up.</a> Cornea. 34 (5), 512-515 (2015).</li><li>Baiocchi, S., Mazzotta, C., Cerretani, D., Caporossi, T., Caporossi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+crosslinking:+riboflavin+concentration+in+corneal+stroma+exposed+with+and+without+epithelium.">Corneal crosslinking: riboflavin concentration in corneal stroma exposed with and without epithelium.</a> J Cataract Refract Surg. 35 (5), 893-899 (2009).</li><li>Wollensak, G., Iomdina, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomechanical+and+histological+changes+after+corneal+crosslinking+with+and+without+epithelial+debridement.">Biomechanical and histological changes after corneal crosslinking with and without epithelial debridement.</a> J Cataract Refract Surg. 35 (3), 540-546 (2009).</li><li>Soeters, N., Wisse, R. P., Godefrooij, D. A., Imhof, S. M., Tahzib, N. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transepithelial+versus+epithelium-off+corneal+cross-linking+for+the+treatment+of+progressive+keratoconus:+a+randomized+controlled+trial.">Transepithelial versus epithelium-off corneal cross-linking for the treatment of progressive keratoconus: a randomized controlled trial.</a> Am J Ophthalmol. 159 (5), 821-828 (2015).</li></ol>

The authors have nothing to disclose.

CXL using UVA irradiation and riboflavin is the standard treatment for arresting the progression of keratoconus. Riboflavin is a photosensitizer which induces chemical covalent bonds (cross-links) when irradiated with UVA3. In the cornea, this phenomenon creates cross-links between collagen fibrils that increase corneal stiffness. Although this phenomenon is well described, until now there has been no direct evidence of intracorneal cross-links. Nonetheless, several studies have reported a stabilization of the...

Keratoconus is a bilateral and progressive corneal ectasia usually reported in 1 in 2,000 in the general population1 resulting in modification of the corneal shape and thus decreased vision2. Keratoconus is usually present in early puberty and progresses until the third to fourth decade of life when the disease typically tends to stabilize, although progression can be variable throughout a patient&#39;s life. By halting keratoconus progression, cross linking aims at postpone or avoid keratoplasty.
To date, the only efficient and safe treatment of progressive keratoconus proven in clinical studies is the conventional corneal collagen cross-linking (C-CXL) protocol, which aims to increase stiffness and hence halt keratoconus progression3-8. In order to reduce operation time and other possible risk factors of C-CXL, such as infectious keratitis or stromal haze9, several improved protocols have been described. First, in accelerated CXL (A-CXL), a higher irradiance of UVA is delivered to the cornea over a reduced time10. Secondly, to avoid the necessity for epithelial debridement, transepithelial approaches have been employed. Unfortunately, they have limited success when compared to the conventional protocol11. The most recent transepithelial method for corneal riboflavin delivery during CXL is iontophoresis (I-CXL), but rigorous evaluation of this treatment has not yet been performed12. Iontophoresis is a non-invasive technique in which a small electric current is applied to improve an ionized drug&#39;s penetration through a tissue. In CXL by iontophoresis, the riboflavin is ionized to penetrate the cornea through the epithelium.
In vivo confocal microscopy (IVCM) is a method of imaging the cornea that can highlight the cellular changes of abnormal corneas in diseases such as keratoconus13. Indeed, IVCM has demonstrated alterations to all layers of the cornea in keratoconus with a particular reduction in density of the sub-basal nerve plexus and stromal keratocytes13-15. Plus, IVCM has proven to be highly convenient for microstructural analysis of the cornea after C-CXL16.
The corneal demarcation line is described as a hyperreflective line seen in anterior segment optical coherence tomography (AS OCT) 1 month after C-CXL at a depth of 300 &#181;m17,18. IVCM following C-CXL provides information about corneal structural alterations, including the absence of corneal keratocytes to a depth of 300 &#181;m. The depth of this acellular zone, as well as the depth of the demarcation line within the corneal stroma revealed on AS OCT, seems to be associated with the effective depth of CXL treatment19, and measurement of the corneal demarcation line depth in AS OCT 1 month after CXL has been proposed as an efficient clinical method for evaluation of CXL effectiveness18.
In the present study we investigate the efficiency of three different protocols of corneal collagen crosslinking (conventional, accelerated, and iontophoresis) using measurement of the corneal stromal demarcation line by AS OCT and confocal microscopy. We furthermore used IVCM to quantitatively analyze corneal microstructure changes after the three treatments.

<table>
	<tbody>
		<tr>
			<td></td>
			<td></td>
			<td>Riboflavin&#160;&#160;&#160;&#160;&#160;&#160;&#160; Product number</td>
			<td></td>
		</tr>
		<tr>
			<td>C-CXL</td>
			<td>Sooft SPA, Montegiorgio, Italy</td>
			<td>Ricrolin&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; 468465-6</td>
			<td></td>
		</tr>
		<tr>
			<td>A-CXL</td>
			<td>Avedro Inc, Waltham, Massachusetts</td>
			<td>VibeX&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; 520-01863-006</td>
			<td></td>
		</tr>
		<tr>
			<td>I-CXL</td>
			<td>Sooft SPA, Montegiorgio, Italy</td>
			<td>Ricrolin+&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; 975481-6</td>
			<td>Passive electrode: PROTENS ELITE 4848LE/ Active electrode: IONTOFOR CXL</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td>UVA Machine</td>
			<td></td>
		</tr>
		<tr>
			<td>X-Vega</td>
			<td></td>
			<td></td>
			<td>UVA: 3 mW/cm2 30 min</td>
		</tr>
		<tr>
			<td>KXL System</td>
			<td></td>
			<td></td>
			<td>UVA: 30 mW/cm2 10 min</td>
		</tr>
		<tr>
			<td>X-Vega</td>
			<td></td>
			<td></td>
			<td>UVA: 10 mW/cm2 9 min</td>
		</tr>
	</tbody>
</table>

three different protocols of corneal collagen crosslinking in keratoconus: conventional, accelerated and iontophoresis

Keratoconus is a bilateral and progressive corneal ectasia. In order to slow down its progression, corneal collagen cross-linking (CXL) has recently been introduced as an efficient treatment option. In biological and chemical sciences, crosslinking refers to new chemical bonds formed between reactive molecules. Hence, the aim of corneal collagen CXL is to synthetically increase the formation of crosslinks between collagen fibrils in the corneal stroma. Despite the fact that the efficiency of the conventional CXL (C-CXL) protocol has already been shown in several clinical studies, it might benefit from improvements in duration of the procedure and removal of corneal epithelium. Hence, in order to provide a coherent evaluation of two new and optimized CXL protocols, we studied keratoconus patients who had undergone one of the three CXL treatments: iontophoresis (I-CXL), accelerated CXL (A-CXL), and conventional CXL (C-CXL). A-CXL is a 6 time faster CXL procedure using a ten time higher UVA irradiance but still including an epithelium removal. Iontophoresis is a transepithelial non-invasive technique in which a small electric current is applied to improve riboflavin penetration throughout the cornea. Using anterior segment optical coherence tomography (AS OCT) and in vivo confocal microscopy (IVCM), we conclude that regarding the depth of treatment penetration, conventional CXL protocol remains the standard for treating progressive keratoconus. Accelerated CXL seems to be a quick, effective and safe alternative to treat thin corneas. The use of iontophoresis is still being investigated and should be considered with greater caution.

The corneal demarcation line was visible in AS OCT in 92% of cases at a mean depth of 301.6 &#181;m (SD, 73.6)
<img alt="Figure 5" src="/files/ftp_upload/53119/53119fig5.jpg" /> 
Figure 5. Demarcation line after C-CXL. High-resolution corneal anterior segment optical coherence tomography scan (AS OCT) visualizing the corneal stromal demarcation line at a mean depth of 358 &#181;m (white arrow), 1 month after conventional corneal colla...

Watch this Scientific Journal Video about Three Different Protocols of Corneal Collagen Crosslinking in Keratoconus: Conventional, Accelerated and Iontophoresis at JoVE.com

Three Different Protocols of Corneal Collagen Crosslinking in Keratoconus: Conventional, Accelerated and Iontophoresis

Corneal collagen cross-linking (CXL) is the only conservative treatment currently available to halt keratoconus progression by improving the biomechanical rigidity of the corneal stroma. The aim of this manuscript is to highlight the methods of three different protocols of CXL: conventional CXL (C-CXL), accelerated CXL (A-CXL), and iontophoresis CXL (I-CXL).

Keratoconus is a bilateral and progressive corneal ectasia. In order to slow down its progression, corneal collagen cross-linking (CXL) has recently been ...

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19.8K Views.  Quinze-Vingts National Ophthalmology Hospital. Corneal collagen cross-linking (CXL) is the only conservative treatment currently available to halt keratoconus progression by improving the biomechanical rigidity of the corneal stroma. The aim of this manuscript is to highlight the methods of three different protocols of CXL: conventional CXL (C-CXL), accelerated CXL (A-CXL), and iontophoresis CXL (I-CXL).

Video: Three Different Protocols of Corneal Collagen Crosslinking in Keratoconus: Conventional, Accelerated and Iontophoresis

Staining Protocols for Human Pancreatic Islets

Estimates of islet area and numbers and endocrine cell composition in the adult human pancreas vary from several hundred thousand to several million and beta mass ranges from 500 to 1500 mg 1-3. With this known heterogeneity, a standard processing and staining procedure was developed so that pancreatic regions were clearly defined and islets characterized using rigorous histopathology and immunolocalization examinations. 
Standardized procedures for processing human pancreas recovered from organ donors are described in part 1 of this series. The pancreas is processed into 3 main regions (head, body, tail) followed by transverse sections. Transverse sections from the pancreas head are further divided, as indicated based on size, and numbered alphabetically to denote subsections. This standardization allows for a complete cross sectional analysis of the head region including the uncinate region which contains islets composed primarily of pancreatic polypeptide cells to the tail region.
The current report comprises part 2 of this series and describes the procedures used for serial sectioning and histopathological characterization of the pancreatic paraffin sections with an emphasis on islet endocrine cells, replication, and T-cell infiltrates. Pathology of pancreatic sections is intended to characterize both exocrine, ductular, and endocrine components. The exocrine compartment is evaluated for the presence of pancreatitis (active or chronic), atrophy, fibrosis, and fat, as well as the duct system, particularly in relationship to the presence of pancreatic intraductal neoplasia4. Islets are evaluated for morphology, size, and density, endocrine cells, inflammation, fibrosis, amyloid, and the presence of replicating or apoptotic cells using H&amp;E and IHC stains. 
The final component described in part 2 is the provision of the stained slides as digitized whole slide images. The digitized slides are organized by case and pancreas region in an online pathology database creating a virtual biobank. Access to this online collection is currently provided to over 200 clinicians and scientists involved in type 1 diabetes research. The online database provides a means for rapid and complete data sharing and for investigators to select blocks for paraffin or frozen serial sections.

This video demonstrates procedures for characterization of human pancreatic islets using hematoxylin and eosin (H&E) and immunohistochemistry (IHC). Pancreatic sections from head, body, and tail regions are stained by both H&amp;E and IHC to determine islet endocrine composition (insulin, glucagon, and pancreatic polypeptide), cell replication (Ki67), and inflammatory infiltrates (H&E, CD3). The uncinate region is localized using IHC for pancreatic polypeptide.

Estimates of islet area and numbers and endocrine cell composition in the adult human pancreas vary from several hundred thousand to several million and ...

An Alkali-burn Injury Model of Corneal Neovascularization in the Mouse

Under normal conditions, the cornea is avascular, and this transparency is essential for maintaining good visual acuity. Neovascularization (NV) of the cornea, which can be caused by trauma, keratoplasty or infectious disease, breaks down the so called &lsquo;angiogenic privilege' of the cornea and forms the basis of multiple visual pathologies that may even lead to blindness. Although there are several treatment options available, the fundamental medical need presented by corneal neovascular pathologies remains unmet. In order to develop safe, effective, and targeted therapies, a reliable model of corneal NV and pharmacological intervention is required. Here, we describe an alkali-burn injury corneal neovascularization model in the mouse. This protocol provides a method for the application of a controlled alkali-burn injury to the cornea, administration of a pharmacological compound of interest, and visualization of the result. This method could prove instrumental for studying the mechanisms and opportunities for intervention in corneal NV and other neovascular disorders.

Neovascularization (NV) of the cornea can complicate multiple visual pathologies. Utilizing a controlled, alkali-burn injury model, a quantifiable level of corneal NV can be produced for mechanistic study of corneal NV and evaluation of potential therapies for neovascular disorders.

Under normal conditions, the cornea is avascular, and this transparency is essential for maintaining good visual acuity. Neovascularization (NV) of the ...

A Rat Model of Ventricular Fibrillation and Resuscitation by Conventional Closed-chest Technique

A rat model of electrically-induced ventricular fibrillation followed by cardiac resuscitation using a closed chest technique that incorporates the basic components of cardiopulmonary resuscitation in humans is herein described. The model was developed in 1988 and has been used in approximately 70 peer-reviewed publications examining a myriad of resuscitation aspects including its physiology and pathophysiology, determinants of resuscitability, pharmacologic interventions, and even the effects of cell therapies. The model featured in this presentation includes: (1) vascular catheterization to measure aortic and right atrial pressures, to measure cardiac output by thermodilution, and to electrically induce ventricular fibrillation; and (2) tracheal intubation for positive pressure ventilation with oxygen enriched gas and assessment of the end-tidal CO2. A typical sequence of intervention entails: (1) electrical induction of ventricular fibrillation, (2) chest compression using a mechanical piston device concomitantly with positive pressure ventilation delivering oxygen-enriched gas, (3) electrical shocks to terminate ventricular fibrillation and reestablish cardiac activity, (4) assessment of post-resuscitation hemodynamic and metabolic function, and (5) assessment of survival and recovery of organ function. A robust inventory of measurements is available that includes &#8211; but is not limited to &#8211; hemodynamic, metabolic, and tissue measurements. The model has been highly effective in developing new resuscitation concepts and examining novel therapeutic interventions before their testing in larger and translationally more relevant animal models of cardiac arrest and resuscitation.

This article describes a rat model of electrically-induced ventricular fibrillation and resuscitation by chest compression, ventilation, and delivery of electrical shocks that simulates an episode of sudden cardiac arrest and conventional cardiopulmonary resuscitation. The model enables gathering insights on the pathophysiology of cardiac arrest and exploration of new resuscitation strategies.

A rat model of electrically-induced ventricular fibrillation followed by cardiac resuscitation using a closed chest technique that incorporates the basic ...

Echocardiographic Approaches and Protocols for Comprehensive Phenotypic Characterization of Valvular Heart Disease in Mice

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in rodents, with detailed descriptions of the appropriate methods for anesthesia, the echocardiographic windows used, the imaging planes and probe orientations for image acquisition, the methods for data analysis, and the limitations of emerging technologies for the evaluation of cardiac and valvular function. Importantly, we also highlight several future areas of research in cardiac and heart valve imaging that may be leveraged to gain insights into the pathogenesis of valve disease in preclinical animal models. We propose that using a systematic approach to evaluating cardiac and heart valve function in mice can result in more robust and reproducible data, as well as facilitate the discovery of previously underappreciated phenotypes in genetically-altered and/or physiologically-stressed mice.

This protocol provides a detailed description of the echocardiographic approach for comprehensive phenotyping of heart and heart valve function in mice.

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in ...

Induction of Accelerated Atherosclerosis in Mice: The "Wire-Injury" Model

Atherosclerosis is a proliferative fibro-inflammatory disease developing in the arterial wall, inducing a deficient blood flow or a lack of blood flow. Moreover, by rupture of the defective vascular wall, atherosclerosis induces occlusive thrombus formation, which represents the main cause of myocardial infarction or stroke and the most frequent cause of death. Despite the advances in the cardiovascular field, many questions remain unanswered, and additional basic research is essential to improve our understanding of the molecular mechanisms during atherosclerosis and its effects. Due to limited clinical studies, there is a need for representative animal models recreating atherosclerotic conditions such as neointima formation after stent implantation, balloon angioplasty, or endarterectomy. Since the mouse presents many advantages and is the most frequently used model for studying molecular processes, the current study proposes an invasive procedure of endothelial denudation, also known as the wire-injury model, which is representative of the human condition of neointima formation in arteries after revascularization procedures.

Induction of Accelerated Atherosclerosis in Mice: The &quot;Wire-Injury&quot; Model

This study describes an invasive procedure for the induction of accelerated atherosclerosis in mice. In comparison to other methods using electric- or cryo-induced injury, mechanical-induced injury mimics the human condition of restenosis after revascularization therapies and is ideal for the study of the molecular mechanisms involved.

Atherosclerosis is a proliferative fibro-inflammatory disease developing in the arterial wall, inducing a deficient blood flow or a lack of blood flow. ...

Corneal Epithelial Abrasion with Ocular Burr As a Model for Cornea Wound Healing

The murine cornea provides an excellent model to study wound healing. The cornea is the outermost layer of the eye, and thus is the first defense to injury. In fact, the most common type of eye injury found in clinic is a corneal abrasion. Here, we utilize an ocular burr to induce an abrasion resulting in removal of the corneal epithelium in vivo on anesthetized mice. This method allows for targeted and reproducible epithelial disruption, leaving other areas intact. In addition, we describe the visualization of the abraded epithelium with fluorescein staining and provide concrete advice on how to visualize the abraded cornea. Then, we follow the timeline of wound healing 0, 18, and 72 h after abrasion, until the wound is re-epithelialized. The epithelial abrasion model of corneal injury is ideal for studies on epithelial cell proliferation, migration and re-epithelialization of the corneal layers. However, this method is not optimal to study stromal activation during wound healing, because the ocular burr does not penetrate to the stromal cell layers. This method is also suitable for clinical applications, for example, pre-clinical test of drug effectiveness.

This protocol describes a method to inflict an abrasion to the ocular surface of the mouse, and to follow the wound healing process thereafter. The protocol takes advantage of an ocular burr to partially remove the surface epithelium of the eye in anaesthetized mice.

The murine cornea provides an excellent model to study wound healing. The cornea is the outermost layer of the eye, and thus is the first defense to ...

Cardiac Magnetic Resonance for the Evaluation of Suspected Cardiac Thrombus: Conventional and Emerging Techniques

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques.&#160;The appearance of a mass on certain magnetic resonance (MR) sequences can help differentiate a thrombus from competing diagnoses such as a tumor. T1 and T2 signal characteristics of a thrombus are related to the evolution of hemoglobin properties. A thrombus typically does not enhance following contrast administration, which also helps differentiation from a tumor. We also highlight the emerging role of T1 mapping in the evaluation of a thrombus, which can add another level of support in diagnosis. Prior to any CMR exam, patient screening and interviews are critical to ensure safety and to optimize patient comfort. Effective communication during the exam between the technologist and the patient promotes proper breath holding technique and higher quality images. Volumetric post processing and structured reporting are helpful to ensure that the radiologist answers the ordering services&#39; question and communicates these results effectively. Optimal pre-MR safety evaluation, CMR exam execution, and post exam processing and reporting allow for delivery of high quality radiological service in the evaluation of a suspected cardiac thrombus.

The goal of this article is to describe how cardiac magnetic resonance can be used for the evaluation and diagnosis of a suspected cardiac thrombus. The method presented will describe data acquisition as well as the pre-procedure and post-procedure protocol.

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques.&#160;The ...

Simultaneous Laryngopharyngeal and Conventional Esophageal pH Monitoring

In addition to typical reflux symptoms, many patients with gastroesophageal reflux disease (GERD) present with extraesophageal symptoms such as cough, hoarseness or asthma, which can be caused by laryngopharyngeal reflux (LPR). Due to their multifactorial origin, those symptoms can be a great diagnostic and therapeutic challenge. Esophageal pH-monitoring is commonly used to determine abnormal esophageal acid exposure and confirm the diagnosis of GERD. However, for better evaluation of acid exposure above the upper esophageal sphincter, a new laryngopharyngeal pH measurement system is now available and may lead to more reliable results in patients with predominantly extraesophageal symptoms. This article aims to present a standardized protocol for simultaneous pH measurement using esophageal and laryngopharyngeal pH probes in order to obtain acid exposure scores from both measurements.

Laryngopharyngeal pH monitoring has been specifically designed to measure acid exposure above the upper esophageal sphincter and complements diagnostic evaluation in patients that present with mainly extraesophageal reflux symptoms. Patients with suspected laryngopharyngeal reflux (LPR) were evaluated using distal esophageal and laryngopharyngeal pH testing simultaneously.

In addition to typical reflux symptoms, many patients with gastroesophageal reflux disease (GERD) present with extraesophageal symptoms such as cough, ...

Three-Dimensional Collagen Matrix Scaffold Implantation as a Liver Regeneration Strategy

Liver diseases are the leading cause of death worldwide. Excessive alcohol consumption, a high-fat diet, and hepatitis C virus infection promote fibrosis, cirrhosis, and/or hepatocellular carcinoma. Liver transplantation is the clinically recommended procedure to improve and extend the life span of patients in advanced disease stages. However, only 10% of transplants are successful, with organ availability, presurgical and postsurgical procedures, and elevated costs directly correlated with that result. Extracellular matrix (ECM) scaffolds have emerged as an alternative for tissue restoration. Biocompatibility and graft acceptance are the main beneficial characteristics of those biomaterials. Although the capacity to restore the size and correct function of the liver has been evaluated in liver hepatectomy models, the use of scaffolds or some kind of support to replace the volume of the extirpated liver mass has not been assessed.
Partial hepatectomy was performed in a rat liver with the xenoimplantation of a collagen matrix scaffold (CMS) from a bovine condyle. Left liver lobe tissue was removed (approximately 40%), and an equal proportion of CMS was surgically implanted. Liver function tests were evaluated before and after the surgical procedure. After days 3, 14, and 21, the animals were euthanized, and macroscopic and histologic evaluations were performed. On days 3 and 14, adipose tissue was observed surrounding the CMS, with no clinical evidence of rejection or infection, as was vessel neoformation and CMS reabsorption at day 21. There was histologic evidence of an insignificant inflammation process and migration of adjacent cells to the CMS, observed with the hematoxylin and eosin (H&#38;E) and Masson&#39;s trichrome staining. The CMS was shown to perform well in liver tissue and could be a useful alternative for studying tissue regeneration and repair in chronic liver diseases.

Liver diseases are induced by many causes that promote fibrosis or cirrhosis. Transplantation is the only option for recovering health. However, given the scarcity of transplantable organs, alternatives must be explored. Our research proposes the implantation of collagen scaffolds in liver tissue from an animal model.

Liver diseases are the leading cause of death worldwide. Excessive alcohol consumption, a high-fat diet, and hepatitis C virus infection promote fibrosis, ...

Ex Vivo and In Vivo Animal Models for Mechanical and Chemical Injuries of Corneal Epithelium

Corneal injury to the ocular surface, including chemical burn and trauma, may cause severe scarring, symblepharon, corneal limbal stem cells deficiency, and result in a large, persistent corneal epithelial defect. Epithelial defect with the following corneal opacity and peripheral neovascularization result in irreversible visual impairment and hinder future management, especially keratoplasty. Since the animal model can be used as an effective drug development platform, models of corneal injury to the mouse and alkali burn to rabbit corneal epithelium are developed here. New Zealand white rabbit is used in the alkali burn model. Different concentrations of sodium hydroxide can be applied onto the central circular area of the cornea for 30 s under intramuscular and topical anesthesia. After copious isotonic normal saline irrigation, residual loose corneal epithelium was removed with corneal burr deep down to the Bowman's layer within this circular area. Wound healing was documented by fluorescein staining under Cobalt blue light. C57BL/6 mice were used in the traumatic model of murine corneal epithelium. The murine central cornea was marked using a skin punch, 2 mm in diameter, and then debrided by a corneal rust ring remover with a 0.5 mm burr under a stereomicroscope. These models can be prospectively used to validate the therapeutic effect of eye drops or mixed agents such as stem cells, which potentially facilitate corneal epithelial regeneration. By observing corneal opacity, peripheral neovascularization, and conjunctival congestion with stereomicroscope and imaging software, therapeutic effects in these animal models can be monitored.

Ex Vivo and In Vivo Animal Models for Mechanical and Chemical Injuries of Corneal Epithelium

Here, animal models based on mouse and rabbit are developed for mechanical and chemical injury of corneal epithelium to screen new therapeutics and the underlying mechanism.

Corneal injury to the ocular surface, including chemical burn and trauma, may cause severe scarring, symblepharon, corneal limbal stem cells deficiency, ...