Name: a standardized obstacle course for assessment of visual function in ultra low vision and artificial vision
Uploaded: 2014-02-11T16:30:00
Description: Watch this Scientific Journal Video about A Standardized Obstacle Course for Assessment of Visual Function in Ultra Low Vision and Artificial Vision at JoVE.com

DCED State of Pennsylvania

1. Course Construction
<ol>
	<li>Install course floor. Course dimensions are 40 ft long by 7 ft wide consisting of 280 1 ft2 portable floor tiles (beige event floor tiles). Place with black trim around perimeter only (Figure 1).</li>
	<li>Paint the adjacent walls to match the floor tiles creating a somewhat monochromatic environment. Colors we used with greyscale values are provided (Table 5). If the specific colors are not available, we recommend taking a tile to a hardware...

<ol>
	<li>Applegate, W. B., Miller, S. T., Elam, J. T., Freeman, J. M., Wood, T. O., Gettlefinger, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+cataract+surgery+with+lens+implantation+on+vision+and+physical+function+in+elderly+patients.">Impact of cataract surgery with lens implantation on vision and physical function in elderly patients.</a> JAMA. 257 (8), 1064-1066 (1987).</li><li>Ebert, E. M., Fine, A. M., Markowitz, J., Maguire, M. G., Starr, J. S., Fine, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+vision+in+patients+with+neovascular+maculopathy+and+poor+visual+acuity.">Functional vision in patients with neovascular maculopathy and poor visual acuity.</a> Arch. Ophthalmol. 104 (7), 1009-1012 (1986).</li><li>Dougherty, B. E., Martin, S. R., Kelly, C. B., Jones, L. 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P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessing+functional+status:+correlation+between+performance+on+tasks+conducted+in+a+clinic+setting+and+performance+on+the+same+task+conducted+at+home.">Assessing functional status: correlation between performance on tasks conducted in a clinic setting and performance on the same task conducted at home.</a> J. Gerontol. A Biol. Sci. Med. Sci. 52 (4), 209-217 (1997).</li><li>Owsley, C., McGwin, G., Sloane, M. E., Stalvey, B. T., Wells, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Timed+instrumental+activities+of+daily+living+tasks:+relationship+to+visual+function+in+older+adults.">Timed instrumental activities of daily living tasks: relationship to visual function in older adults.</a> Optom. Vis. Sci. 78 (5), 350-359 (2001).</li><li>Mangione, C. M., Lee, P. P., Gutierrez, P. R., Spritzer, K., Berry, S., Hays, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=National+Eye+Institute+Visual+Function+Questionnaire+Field+Test+Investigators.+Development+of+the+25-item+National+Eye+Institute+Visual+Function+Questionnaire.">National Eye Institute Visual Function Questionnaire Field Test Investigators. Development of the 25-item National Eye Institute Visual Function Questionnaire.</a> Arch. Ophthalmol. 119 (7), 1050-1058 (2001).</li><li>Massof, R. W., Rubin, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+function+assessment+questionnaires.">Visual function assessment questionnaires.</a> Surv. Ophthalmology. 45 (6), 531-548 (2001).</li><li>Massof, R. W., Fletcher, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+NEI+visual+functioning+questionnaire+as+an+interval+measure+of+visual+ability+in+low+vision.">Evaluation of the NEI visual functioning questionnaire as an interval measure of visual ability in low vision.</a> Vision Res. 41, 397-413 (2001).</li><li>Stelmack, J. A., Stelmack, T. R., Massof, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+low-vision+rehabilitation+outcomes+with+the+NEI+VFQ-25.">Measuring low-vision rehabilitation outcomes with the NEI VFQ-25.</a> Invest. Ophthalmol Vis Sci. 43 (9), 2859-2868 (2002).</li><li>Stelmack, J. A., Szlyk, J. P., Stelmack, T. R., Demers-Turco, P., Williams, R. T., Moran, D., Massof, R. 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K., Dagnelie, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Orientation+and+mobility+assessment+in+retinal+prosthetic+clinical+trials.">Orientation and mobility assessment in retinal prosthetic clinical trials.</a> Optom. Vis. Sci. 89 (9), 1308-1315 (2012).</li><li>Chader, G. J., Weiland, J., Humayun, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Artificial+vision:+needs,+functioning,+and+testing+of+a+retinal+electronic+prosthesis.">Artificial vision: needs, functioning, and testing of a retinal electronic prosthesis.</a> Prog. Brain Res. 175, 317-332 (2009).</li><li>Sachs, H. G., Veit-Peter, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinal+replacement--the+development+of+microelectronic+retinal+prostheses--experience+with+subretinal+implants+and+new+aspects.">Retinal replacement--the development of microelectronic retinal prostheses--experience with subretinal implants and new aspects.</a> Graefes Arch. Clin. Exp. Ophthalmol. 242 (8), 717-723 (2004).</li><li>Alteheld, N., Roessler, G., Walter, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Towards+the+bionic+eye--the+retina+implant:+surgical,+opthalmological+and+histopathological+perspectives.">Towards the bionic eye--the retina implant: surgical, opthalmological and histopathological perspectives.</a> Acta Neurochir. Suppl. 97 (2), 487-493 (2007).</li><li>Benav, H., 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=Restoration+of+useful+vision+up+to+letter+recognition+capabilities+using+subretinal+microphotodiodes).">Restoration of useful vision up to letter recognition capabilities using subretinal microphotodiodes).</a> Conf. Proc. IEEE Eng. Med. Biol. Soc. , 5919-5922 (2010).</li><li>Rizzo, J. F., Wyatt, J., Loewenstein, J., Kelly, S., Shire, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perceptual+efficacy+of+electrical+stimulation+of+human+retina+with+a+microelectrode+array+during+short-term+surgical+trials.">Perceptual efficacy of electrical stimulation of human retina with a microelectrode array during short-term surgical trials.</a> Invest. Ophthalmol. Vis. Sci. 44 (12), 5362-5369 (2003).</li><li>Rizzo, J. F., Wyatt, J., Loewenstein, J., Kelly, S., Shire, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+and+perceptual+thresholds+for+short-term+electrical+stimulation+of+human+retina+with+microelectrode+arrays.">Methods and perceptual thresholds for short-term electrical stimulation of human retina with microelectrode arrays.</a> Invest. Ophthalmol. Vis. Sci. 44 (12), 5355-5361 (2003).</li><li>Humayun, M. 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=Argus+II+Study+Group.+Interim+results+from+the+international+trial+of+Second+Sight's+visual+prosthesis.">Argus II Study Group. Interim results from the international trial of Second Sight's visual prosthesis.</a> Ophthalmology. 119 (4), 779-788 (2012).</li><li>Danilov, Y., Tyler, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brainport:+an+alternative+input+to+the+brain.">Brainport: an alternative input to the brain.</a> J. Integr. Neurosci. 4 (4), 537-550 (2005).</li><li>Merabet, L. B., Battelli, L., Obretenova, S., Maguire, S., Meijer, P., Pascual-Leone, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+recruitment+of+visual+cortex+for+sound+encoded+object+identification+in+the+blind.">Functional recruitment of visual cortex for sound encoded object identification in the blind.</a> Neuroreport. 20 (2), 132-138 (2009).</li><li>Arfken, C. L., Lach, H. W., McGee, S., Birge, S. J., Miller, J. 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We describe an indoor, portable, easily reproducible, and relatively inexpensive course that can be used to evaluate obstacle avoidance in persons who are blind or have low vision. Most current obstacle course designs and tests (i.e. TUGS) are difficult to compare across sites and observers, or are permanent instillations which cannot readily be performed at alternate locations16,17,30. Our goal was to create a course that could be standardized for use at different locations and with different observe...

Low vision rehabilitation assessments must determine whether intervention results in improvement in function. Performance metrics typically involve computer based&#160;reading&#160;or functional assessments1-9&#160;as well as quality of life questionnaires10-15. Being able to also assess the low vision patient&#39;s ability to navigate around obstacles might also provide clues to functional improvements18&#160;particularly in the case of artificial vision devices. Geruschat et al. recently published navigation outcomes with a retinal implant chip, highlighting the need for a standard metric in this area17. Currently there are no widely accepted, objective, validated, and comprehensive standards for determining capacity for obstacle avoidance.
Development of a functional test that would correlate to navigation performance for persons with low vision or &#34;ultra low vision&#34; as produced by artificial vision would be desirable, but has remained an elusive goal. The burgeoning field of artificial vision devices such as retinal implant chips18-24&#160;or sensory substitution devices such as the BrainPort 25&#160;and The vOICe26, necessitates a test of obstacle avoidance that might correlate to increased navigational abilities conferred by these devices. Such an assessment would not only allow subjects to understand their own limitations as they traverse their surroundings, but might provide a means for measuring improvement with orientation and mobility training or between iterations of vision enhancement prototype devices. Ideally, there might be some ability to assess an individual&#39;s risk for fall accidents27.
Our goal was to create an obstacle course that would be useful for evaluation of navigation ability in patients using artificial vision devices and transferrable to the field of low vision in general. A review of the published literature on obstacle courses and visual impairment was undertaken using the PubMed database. There have been numerous attempts at creating standardized obstacle courses16,17,28-31,34. Most of these are not portable in the sense that it would be difficult to exactly reproduce the setting, particularly for outdoor courses. Maguire et al. describe obstacle course which is used to show mobility performance in patients with Leber&#39;s Congenital Amaurosis. This course has the benefit of being portable and small, but it is not clear whether different iterations have been made available to prevent memorization effects, nor are there any provisions for obstacles which are not on the floor, texture changes, or stepovers. Leat provides an incisive description of potential pitfalls in designing a course and puts forth a description of an outdoor course which unfortunately would not be able to be reproduced exactly in an alternative location30. Velikay-Parel et al. described a mobility test for use with retinal implant chips. This design had the benefit of being portable and simple to execute. While this course could be reproduced at an alternative site, no specific details on course construction are provided. Moreover, and more concerning was that they showed the learning effect reached asymptotic levels due to course familiarity, therefore being able to prevent course memorization altogether might eliminate the concern for loss of learning effect over time18. None of the courses described so far have been widely adopted by the low-vision or rehabilitation communities.
The authors subsequently consulted with a team of six low vision occupational therapists and orientation and mobility specialists from the Western Pennsylvania School for Blind Children (Pittsburgh, PA) and the Blind and Vision Services Rehabilitation of Pittsburgh (Homestead, PA) regarding proposed course design. Desirable attributes of a functional obstacle course identified included: Portability for easy assembly/disassembly and storage, flexibility to test under both dim and bright lighting conditions, and to mirror &#34;real life&#34; situations by including obstacles that represent objects in a patient&#39;s home environment that are sturdy enough to withstand repeated collision while being ductile in order to prevent patient injury. In addition it was deemed necessary to have several types of environments designed in such as way so that when administered in a randomized order prevents course memorization. In addition, the course should demonstrate reproducible results in multiple settings, have strong inter and intra rater reliability and be an objective measure of spatial awareness.
The culmination of this effort was development of an obstacle course which could reasonably be expected to be reproduced in a standard institutional hallway. The course is designed to test different skill sets, all important for navigation. Each level of the course attempts to focus several particular types of obstacles encountered in everyday navigation activities. The first course evaluates the ability to navigate through relatively high contrast targets that are all placed on the floor, but requires a large number of turns. The second course evaluates the ability to navigate through obstacles that are both high and low contrast, floor texture changes, and objects suspended in air. The final course evaluates the ability to navigate Styrofoam obstacles that are low contrast, surface glare changes on the floor, the addition of nonStyrofoam obstacles (fabric), floor tile color changes, obstacles that must be stepped over, and obstacles that are not on the floor. The courses are labeled 1, 2, and 3 for ease of labeling, but this designation should not be construed as increasing in level of difficulty. Within each level, there are three versions of the course, which can be randomized to prevent course memorization.

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			<td height="35" style="height:35px;width:216px;">Event Floor Tiles, beige</td>
			<td style="width:192px;">Snaplock Industries, Salt Lake City UT</td>
			<td style="width:119px;"></td>
			<td style="width:163px;">Beige</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:216px;">Event Floor Tiles, black trim</td>
			<td style="width:192px;">Snaplock Industries, Salt Lake City UT</td>
			<td style="width:119px;"></td>
			<td style="width:163px;">Male loop</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:216px;">Event Floor Tiles, black trim</td>
			<td style="width:192px;">Snaplock Industries, Salt Lake City UT</td>
			<td style="width:119px;"></td>
			<td style="width:163px;">Female loop</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:216px;">Event Floor Tiles, Edging</td>
			<td style="width:192px;">Snaplock Industries, Salt Lake City UT</td>
			<td style="width:119px;"></td>
			<td style="width:163px;">Black</td>
		</tr>
		<tr height="52">
			<td height="52" style="height:52px;width:216px;">Wall Paint: Satin Premium Plus Internal Satin Enamel Custom Color Match</td>
			<td style="width:192px;">Behr, Inc Santa Ana CA</td>
			<td style="width:119px;">custom</td>
			<td style="width:163px;">Greyscale value = 45</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:216px;">Obstacle paint</td>
			<td style="width:192px;">Valspar Paints, Wheeling, IL</td>
			<td style="width:119px;">DuJour (#70002-6)</td>
			<td style="width:163px;">DuJour Greyscale value = 15</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:216px;">Obstacle paint</td>
			<td style="width:192px;">Valspar Paints, Wheeling, IL</td>
			<td style="width:119px;">Fired Earth (#6011-1)</td>
			<td style="width:163px;">Fired Earth Greyscale value = 95</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:216px;">Styrofoam obstacles</td>
			<td style="width:192px;">Universal Foam Products, Orlando CA</td>
			<td style="width:119px;">custom</td>
			<td style="width:163px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Con-Tact Brand Contact Paper</td>
			<td style="width:192px;">Lowe&#39;s Home Improvement</td>
			<td align="right" style="width:119px;">639982</td>
			<td style="width:163px;">Solid Black</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Con-Tact Brand Contact Paper</td>
			<td style="width:192px;">Lowe&#39;s Home Improvement</td>
			<td align="right" style="width:119px;">615542</td>
			<td style="width:163px;">Stainless Steel</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Con-Tact Brand Contact Paper</td>
			<td style="width:192px;">Lowe&#39;s Home Improvement</td>
			<td align="right" style="width:119px;">614416</td>
			<td style="width:163px;">Solid White</td>
		</tr>
		<tr height="52">
			<td height="52" style="height:52px;width:216px;">3 ft x 6 ft Standard tuff Olefin Floor Mat</td>
			<td style="width:192px;">Commercial Mats and Rubber A Division of Georgia Mills Direct Saratoga Springs, NY</td>
			<td style="width:119px;"></td>
			<td style="width:163px;">Charcoal</td>
		</tr>
		<tr height="52">
			<td height="52" style="height:52px;width:216px;">3 ft x 6 ft Standard tuff Olefin Floor Mat</td>
			<td style="width:192px;">Commercial Mats and Rubber A Division of Georgia Mills Direct Saratoga Springs, NY</td>
			<td style="width:119px;"></td>
			<td style="width:163px;">Smoke</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:216px;">Fisher Scientific Traceable Dual Range Light Meter</td>
			<td style="width:192px;">Fisher Scientific</td>
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a standardized obstacle course for assessment of visual function in ultra low vision and artificial vision

We describe an indoor, portable, standardized course that can be used to evaluate obstacle avoidance in persons who have ultralow vision. Six sighted controls and 36 completely blind but otherwise healthy adult male (n=29) and female (n=13) subjects (age range 19-85 years), were enrolled in one of three studies involving testing of the BrainPort sensory substitution device. Subjects were asked to navigate the course prior to, and after, BrainPort training. They completed a total of 837 course runs in two different locations. Means and standard deviations were calculated across control types, courses, lights, and visits. We used a linear mixed effects model to compare different categories in the PPWS (percent preferred walking speed) and error percent data to show that the course iterations were properly designed. The course is relatively inexpensive, simple to administer, and has been shown to be a feasible way to test mobility function. Data analysis demonstrates that for the outcome of percent error as well as for percentage preferred walking speed, that each of the three courses is different, and that within each level, each of the three iterations are equal. This allows for randomization of the courses during administration.
Abbreviations: 
preferred walking speed (PWS) 
course speed (CS) 
percentage preferred walking speed (PPWS)

Subjects
Six sighted blindfolded, sighted, and 36 completely blind but otherwise healthy adult (age range 19-85 years), male (n=29) and female (n=13) subjects were enrolled in one of three studies involving testing of the BrainPort sensory substitution device (Wicab, Madison WI). All studies were approved by the University of Pittsburgh IRB and all subjects signed an approved informed consent document. All studies were a within subjects, repeated measures design such that each subject acted as th...

Watch this Scientific Journal Video about A Standardized Obstacle Course for Assessment of Visual Function in Ultra Low Vision and Artificial Vision at JoVE.com

A Standardized Obstacle Course for Assessment of Visual Function in Ultra Low Vision and Artificial Vision

We describe an indoor, portable, standardized course that can be used to evaluate obstacle avoidance in persons who have ultralow vision. The course is relatively inexpensive, simple to administer, and has been shown to be reliable and reproducible.

We describe an indoor, portable, standardized course that can be used to evaluate obstacle avoidance in persons who have ultralow vision. Six sighted ...

a-standardized-obstacle-course-for-assessment-visual-function-ultra

Research

JoVE Journal

Medicine

The Measurement and Treatment of Suppression in Amblyopia

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current estimates put the prevalence of amblyopia at approximately 1-3%1-3, the majority of cases being monocular2. Amblyopia is most frequently caused by ocular misalignment (strabismus), blur induced by unequal refractive error (anisometropia), and in some cases by form deprivation.
Although amblyopia is initially caused by abnormal visual input in infancy, once established, the visual deficit often remains when normal visual input has been restored using surgery and/or refractive correction. This is because amblyopia is the result of abnormal visual cortex development rather than a problem with the amblyopic eye itself4,5 . Amblyopia is characterized by both monocular and binocular deficits6,7 which include impaired visual acuity and poor or absent stereopsis respectively. The visual dysfunction in amblyopia is often associated with a strong suppression of the inputs from the amblyopic eye under binocular viewing conditions8. Recent work has indicated that suppression may play a central role in both the monocular and binocular deficits associated with amblyopia9,10 .
Current clinical tests for suppression tend to verify the presence or absence of suppression rather than giving a quantitative measurement of the degree of suppression. Here we describe a technique for measuring amblyopic suppression with a compact, portable device11,12 . The device consists of a laptop computer connected to a pair of virtual reality goggles. The novelty of the technique lies in the way we present visual stimuli to measure suppression. Stimuli are shown to the amblyopic eye at high contrast while the contrast of the stimuli shown to the non-amblyopic eye are varied. Patients perform a simple signal/noise task that allows for a precise measurement of the strength of excitatory binocular interactions. The contrast offset at which neither eye has a performance advantage is a measure of the "balance point" and is a direct measure of suppression. This technique has been validated psychophysically both in control13,14 and patient6,9,11 populations.
In addition to measuring suppression this technique also forms the basis of a novel form of treatment to decrease suppression over time and improve binocular and often monocular function in adult patients with amblyopia12,15,16 . This new treatment approach can be deployed either on the goggle system described above or on a specially modified iPod touch device15.

Amblyopia is a developmental disorder of the visual cortex that is often accompanied by strong suppression of one eye. We present a new technique for measuring and treating interocular suppression in patients with amblyopia that can be deployed using virtual reality goggles or a portable iPod Touch device.

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current ...

Detecting Abnormalities in Choroidal Vasculature in a Mouse Model of Age-related Macular Degeneration by Time-course Indocyanine Green Angiography

Indocyanine Green&#160;Angiography (or ICGA) is a technique performed by ophthalmologists to diagnose abnormalities of the choroidal and retinal vasculature of various eye diseases such as age-related macular degeneration (AMD). ICGA is especially useful to image the posterior choroidal vasculature of the eye due to its capability of penetrating through the pigmented layer with its infrared spectrum. ICGA time course can be divided into early, middle, and late phases. The three phases provide valuable information on the pathology of eye problems. Although time-course ICGA by intravenous (IV) injection is widely used in the clinic for the diagnosis and management of choroid problems, ICGA by intraperitoneal injection (IP) is commonly used in animal research. Here we demonstrated the technique to obtain high-resolution ICGA time-course images in mice by tail-vein injection and confocal scanning laser ophthalmoscopy. We used this technique to image the choroidal lesions in a mouse model of age-related macular degeneration. Although it is much easier to introduce ICG to the mouse vasculature by IP, our data indicate that it is difficult to obtain reproducible ICGA time course images by IP-ICGA. In contrast, ICGA via tail vein injection provides high quality ICGA time-course images comparable to human studies. In addition, we showed that ICGA performed on albino mice gives clearer pictures of choroidal vessels than that performed on pigmented mice. We suggest that time-course IV-ICGA should become a standard practice in AMD research based on animal models.

Indocyanine Green Angiography (or ICGA) performed by tail vein injection provides high quality ICGA time course images to characterize abnormalities in mouse choroid.

Indocyanine Green&#160;Angiography (or ICGA) is a technique performed by ophthalmologists to diagnose abnormalities of the choroidal and retinal ...

Slow-release Drug Delivery through Elvax 40W to the Rat Retina: Implications for the Treatment of Chronic Conditions

Diseases of the retina are difficult to treat as the retina lies deep within the eye. Invasive methods of drug delivery are often needed to treat these diseases. Chronic retinal diseases such as retinal oedema or neovascularization usually require multiple intraocular injections to effectively treat the condition. However, the risks associated with these injections increase with repeated delivery of the drug. Therefore, alternative delivery methods need to be established in order to minimize the risks of reinjection. Several other investigations have developed methods to deliver drugs over extended time, through materials capable of releasing chemicals slowly into the eye. In this investigation, we outline the use of Elvax 40W, a copolymer resin, to act as a vehicle for drug delivery to the adult rat retina. The resin is made and loaded with the drug. The drug-resin complex is then implanted into the vitreous cavity, where it will slowly release the drug over time. This method was tested using 2-amino-4-phosphonobutyrate (APB), a glutamate analogue that blocks the light response of the retina. It was demonstrated that the APB was slowly released from the resin, and was able to block the retinal response by 7 days after implantation. This indicates that slow-release drug delivery using this copolymer resin is effective for treating the retina, and could be used therapeutically with further testing.

This paper details how Elvax 40W can be used as a slow-release method for drug delivery to the adult rat retina. The protocol for preparing, loading, and delivering the drug-resin complex to the eye is described.

Diseases of the retina are difficult to treat as the retina lies deep within the eye. Invasive methods of drug delivery are often needed to treat these ...

Using Adeno-associated Virus as a Tool to Study Retinal Barriers in Disease

M&#252;ller cells are the principal glial cells of the retina. Their end-feet form the limits of the retina at the outer and inner limiting membranes (ILM), and in conjunction with astrocytes, pericytes and endothelial cells they establish the blood-retinal barrier (BRB). BRB limits material transport between the bloodstream and the retina while the ILM acts as a basement membrane that defines histologically the border between the retina and the vitreous cavity. Labeling M&#252;ller cells is particularly relevant to study the physical state of the retinal barriers, as these cells are an integral part of the BRB and ILM. Both BRB and ILM are frequently altered in retinal disease and are responsible for disease symptoms.
There are several well-established methods to study the integrity of the BRB, such as the Evans blue assay or fluorescein angiography. However these methods do not provide information on the extent of BRB permeability to larger molecules, in nanometer range. Furthermore, they do not provide information on the state of other retinal barriers such as the ILM. To study BRB permeability alongside retinal ILM, we used an AAV based method that provides information on permeability of BRB to larger molecules while indicating the state of the ILM and extracellular matrix proteins in disease states. Two AAV variants are useful for such study: AAV5 and ShH10. AAV5&#160;has a natural tropism for photoreceptors but it cannot get across to the outer retina when administered into the vitreous when the ILM is intact (i.e., in wild-type retinas). ShH10 has a strong tropism towards glial cells and will selectively label M&#252;ller glia in both healthy and diseased retinas. ShH10 provides more efficient gene delivery in retinas where ILM is compromised. These viral tools coupled with immunohistochemistry and blood-DNA analysis shed light onto the state of retinal barriers in disease.

To investigate the blood-retinal barrier permeability and the inner limiting membrane integrity in animal models of retinal disease, we used several adeno-associated virus (AAV) variants as tools to label retinal neurons and glia. Virus mediated reporter gene expression is then used as an indicator of retinal barrier permeability.

M&#252;ller cells are the principal glial cells of the retina. Their end-feet form the limits of the retina at the outer and inner limiting membranes ...

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.

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 ...

Regenerative Therapy by Suprachoroidal Cell Autograft in Dry Age-related Macular Degeneration: Preliminary In Vivo Report

This study is aimed at examining whether a suprachoroidal graft of autologous cells can improve best corrected visual acuity (BCVA) and responses to microperimetry (MY) in eyes affected by dry Age-related Macular Degeneration (AMD) over time through the production and secretion of growth factors (GFs) on surrounding tissue. Patients were randomly assigned to each study group. All patients were diagnosed with dry AMD and with BCVA equal to or greater than 1 logarithm of the minimum angle of resolution (logMAR). A suprachoroidal autologous graft by Limoli Retinal Restoration Technique (LRRT) was carried out on group A, which included 11 eyes from 11 patients. The technique was performed by implanting adipocytes, adipose-derived stem cells obtained from the stromal vascular fraction, and platelets from platelet-rich plasma in the suprachoroidal space. Conversely, group B, including 14 eyes of 14 patients, was used as a control group. For each patient, diagnosis was verified by confocal scanning laser ophthalmoscope and spectral domain-optical coherence tomography (SD-OCT). In group A, BCVA improved by 0.581 to 0.504 at 90 days and to 0.376 logMAR at 180 days (+32.20%) postoperatively. Furthermore, MY test increased by 11.44 dB to 12.59 dB at 180 days. The different cell types grafted behind the choroid were able to ensure constant GF secretion in the choroidal flow. Consequently, the results indicate that visual acuity (VA) in the grafted group can increase more than in the control group after six months.

Regenerative Therapy by Suprachoroidal Cell Autograft in Dry Age-related Macular Degeneration: Preliminary In Vivo Report

The goal of this study is to assess whether the suprachoroidal graft of adipose-derived stem cells included in the stromal vascular fraction and platelets derived from platelet-rich plasma by the Limoli Retinal Restoration Technique can improve visual acuity and retinal sensitivity responses in eyes affected by dry age-related macular degeneration.

This study is aimed at examining whether a suprachoroidal graft of autologous cells can improve best corrected visual acuity (BCVA) and responses to ...

Puncture-Induced Iris Neovascularization as a Mouse Model of Rubeosis Iridis

We describe a model of puncture-induced iris neovascularization as a general model for noninvasive evaluation of angiogenesis. The model is also relevant for targeting neovascular glaucoma, a sight-threatening complication of diabetic retinopathy. This method is based on the induction of iris vascular response by a series of self-sealing uveal punctures on BALB/c mice and takes advantage of the postpartum maturation of mouse ocular vasculature. Mouse pups undergo uveal punctures from postnatal day 12.5, when the pups naturally open their eyes, until postnatal day 24.5. Due to the transparency of the cornea, iris vasculature can be analyzed easily through time by noninvasive in vivo methods. Furthermore, the semitransparent iris of BALB/c mice can be flatmounted for detailed immunohistologic analysis with minimal non-specific background staining. In this model, angiogenesis is mainly driven by the inflammatory and plasminogen activating systems. The puncture-induced model is the first to induce iris neovascularization in small rodents, and has the advantage of allowing direct noninvasive in vivo analysis of the angiogenic process. Moreover, the model can be combined with angiogenic modulating substances, which highlights its potential in the study of angiogenesis with an in vivo perspective.

Iris neovascularization, a common complication of ischemic retinal disease, may lead to sight-threatening neovascular glaucoma. Here, we describe a murine protocol for inducing experimental iris neovascularization that may be used for noninvasive evaluation of angiogenesis-modulating substances.

We describe a model of puncture-induced iris neovascularization as a general model for noninvasive evaluation of angiogenesis. The model is also relevant ...

A Model of Glaucoma Induced by Circumlimbal Suture in Rats and Mice

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known risk factor for glaucoma. This protocol demonstrates a step-by-step guide on this technique in Long Evans rats and C57BL/6 mice. Under general anesthesia, a "purse-string" suture is applied on the conjunctiva, around the equator and behind the limbus of the eye. The fellow eye serves as an untreated control. Over the duration of our study, which was a period of 8 weeks for rats and 12 weeks for mice, IOP remained elevated, as measured regularly by rebound tonometry in conscious animals without topical anesthesia. In both species, the sutured eyes showed electroretinogram features consistent with preferential inner retinal dysfunction. Optical coherence tomography showed selective thinning of the retinal nerve fiber layer. Histology of the rat retina in cross-section found reduced cell density in the ganglion cell layer, but no change in other cellular layers. Staining of flat-mounted mouse retinae with a ganglion cell specific marker (RBPMS) confirmed ganglion cell loss. The circumlimbal suture is a simple, minimally invasive and cost-effective way to induce ocular hypertension that leads to ganglion cell injury in both rats and mice.

Chronic ocular hypertension is induced by applying a circumlimbal suture in rats and mice, leading to functional and structural deterioration of the retinal ganglion cells consistent with glaucoma.

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known ...

Non-invasive Assessment of Dorsiflexor Muscle Function in Mice

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively affect skeletal muscle. This can result in a loss of muscle mass (atrophy) and/or loss of muscle quality (reduced force per unit of muscle mass), both of which are prevalent in chronic disease, muscle-specific disease, immobilization, and aging (sarcopenia). Skeletal muscle function in animals can be evaluated by a range of different tests. All tests have limitations related to the physiological testing environment, and the selection of a specific test often depends on the nature of the experiments. Here, we describe an in vivo, non-invasive technique involving a helpful and easy assessment of force frequency-curve (FFC) in mice that can be performed on the same animal over time. This permits monitoring of disease progression and/or efficacy&#160;of a potential therapeutic treatment.

Measurement of rodent skeletal muscle contractile function is a useful tool that can be used to track disease progression as well as efficacy of therapeutic intervention. We describe here the non-invasive, in vivo assessment of the dorsiflexor muscles that can be repeated over time in the same mouse.

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively ...

Effect of Artificial Tear Formulations on the Metabolic Activity of Human Corneal Epithelial Cells after Exposure to Desiccation

Artificial lipid-containing tear formulations are developed to reduce tear evaporation by the restoration of a deficient tear lipid layer. Artificial tear formulations that prevent cell desiccation will result in ocular surface protection and the maintenance of cell metabolic activity. During dehydration, cells undergo the process of loss of metabolic activity and subsequently cell death. This work describes a method for assessing the efficacy of artificial tear formulations. The metabolic dye (i.e., alamarBlue) changes from a low fluorescent molecule resazurin to a fluorescent molecule resorufin in viable cells. The biological performance of an artificial tear formulation is measured as the ability of the formulation to (a) maintain cell viability and (b) provide cell protection from desiccation. Growth media and saline are used as controls for the cell viability/desiccation tests. Cells are incubated with test solutions for 30 min and then desiccated for 0 or 5 min at 37 &#176;C and 45% relative humidity. Cell metabolic activity after initial exposure and after cell desiccation is then determined. The results show the comparative effects of eye drop formulations on cell metabolic activity and desiccation protection. This method can be used to test dry eye formulations that are designed to treat individuals with evaporative dry eye.

The purpose of this protocol is to evaluate if different artificial tear formulations can protect human corneal epithelial cells from desiccation using an in vitro model. After exposure to artificial tear formulations and desiccation, human corneal epithelial cells are assessed for metabolic activity.

Artificial lipid-containing tear formulations are developed to reduce tear evaporation by the restoration of a deficient tear lipid layer. Artificial tear ...