Name: Video: Corneal Flap Creation and Stromal Ablation in Laser Eye Surgery in Humans
Uploaded: 2024-09-20T13:50:00
Description: 51 Views. Corneal Flap Creation and Stromal Ablation in Laser Eye Surgery in Humans

corneal flap creation and stromal ablation in laser eye surgery in humans

Excimer Laser Multifocal Double Aspheric Ablation for Presbyopia Correction

Presbyopia is an age-related reduction in amplitude of accommodation leading to loss of near vision due to the loss of function of the lens and ciliary muscle1. The global population of presbyopes is projected to exceed 2 billion by 2030, with uncorrected and undercorrected presbyopia affecting socio-economic development2. Correction of presbyopia includes lens correction, surgical approaches, and medication. Corneal surgery is one of the main forms of corneal surgery to correct presbyopia because of its less invasive nature, fewer complications, and faster recovery3.
Ruiz introduced Presby laser-assisted in situ keratomileusis (LASIK) in 1996, which ablates the cornea into a multifocal pattern and increases the negative SA to achieve simultaneous near and distance vision4,5. Depending on the proximity area, Presby LASIK can be categorized into peripheral model6 (peripheral area for near vision and central area for distance vision) and central model7(peripheral area for distance vision and central area for near vision)8,9. The monocular bi-aspheric ablation profile is a hybrid Presby LASIK that combines the advantages of multiple programs, including micro-monocular vision, bi-aspheric, and multifocal. The dominant eye is completely corrected for distance vision, the central zone of the non-dominant eye retains approximately -0.89D of refraction for near vision, the peripheral cornea is ablated for distance vision, and the range of near addition (ADD) is between +1.25D to 2.50D, and aspheric cutting is used in both the central and peripheral zones10,11.
Compared with the previous monovision LASIK, the multifocal morphology of the non-dominant eye after the monocular bi-aspheric ablation profile reduces the anisometropia between the two eyes. The negative increase of SA introduces the depth of focus, which can better improve near vision and, at the same time, improve the intermediate vision, reduce the impact on stereopsis, and improve the patient&#39;s acceptance and satisfaction11,12,13. The monocular mode will lead to complete correction of the dominant eye, which can achieve the fastest postoperative clear full vision, reduce the risk of UDVA decline, and is more suitable for patients with presbyopia who have the same requirements for UDVA and UIVA, while other algorithms are multifocal in both eyes, which need more time for adaptation after surgery and have the risk of UDVA decline14,15,16. This article describes the detailed surgical steps of excimer laser multifocal double aspheric ablation mode as a surgical guide.

Author Spotlight: Advancements in Refractive Surgical Correction for Presbyopia and Exploring Postoperative Visual Acuity

Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile

Corneal Flap Creation and Stromal Ablation in Laser Eye Surgery in Humans

corneal-flap-creation-stromal-ablation-laser-eye-surgery

Research

JoVE Journal

Medicine

51 Views. Corneal Flap Creation and Stromal Ablation in Laser Eye Surgery in Humans

Video: Corneal Flap Creation and Stromal Ablation in Laser Eye Surgery in Humans

The study aims to evaluate visual acuity and objective visual quality before and after the monocular bi-aspheric ablation profile for correction of presbyopia surgery. This prospective self-control study included 20 cases and 38 eyes of patients who underwent monocular bi-aspheric ablation profile correction of myopia with presbyopia at the Eye Hospital of Shandong University of Traditional Chinese Medicine from January 2023 to January 2024. These patients were selected for observation, and each patient's preoperative and postoperative uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), spherical aberration (SA) (within 6 mm), horizontal and vertical coma (within 6 mm), and corneal aspheric index (Q-value) (within 6 mm) were evaluated. Statistical data analysis was performed at different time points before and after the operation. There were statistically significant differences in UDVA between dominant and non-dominant eyes before and after surgery (Z = -3.784, p &lt; 0.001; Z = -3.817, p &lt; 0.001). Post-operatively, 90% of the non-dominant eyes achieved UNVA of J1 and above, and 95% of the bilateral eyes achieved UNVA of J1 and above. Significant differences were found in the SA of the dominant eyes, which showed a positive increase (Z= -3.784, p &lt; 0.001); however, compared with the dominant eye, the SA of the non-dominant eye was negatively increased, but the difference was not statistically significant (p = 0.08). There was a significant difference in the vertical coma of the dominant eye before and after the operation, but there was no significant difference in non-dominant eyes. There was no significant difference in the change of binocular horizontal coma before and after the operation. There were significant changes in the Q value of both eyes before and after the operation (Z = -3.923, p &lt; 0.001; Z = -3.51, p &lt; 0.001). After the monocular bi-aspheric ablation profile, the cornea of the non-dominant eye showed a prolate shape, negative SA increased, and the UDVA and UNVA improved after the operation.

This article provides a step-by-step guide to correcting presbyopia with a monocular bi-aspheric ablation profile.

The study aims to evaluate visual acuity and objective visual quality before and after the monocular bi-aspheric ablation profile for correction of ...