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Changes in mesopic vision after photorefractive keratectomy for myopia
Zoltán Z Nagy1, Györgyi Munkácsy, Ronald R Krueger
11st Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
Summary
Excimer laser eye treatments with larger 6.5mm diameters using flying spot technology showed better mesopic vision and glare sensitivity than smaller 5.0mm diameters. Unoperated eyes had the best outcomes in all mesopic functions tested.
Area of Science:
- Ophthalmology
- Refractive Surgery
- Corneal Surgery
Background:
- Excimer laser refractive surgery aims to correct vision by reshaping the cornea.
- Mesopic vision and glare sensitivity are crucial for visual function, particularly in low light conditions.
- Different laser systems and treatment parameters may influence visual outcomes.
Purpose of the Study:
- To compare mesopic visual functions after excimer laser treatment with varying diameters and beam delivery systems.
- To evaluate the impact of scanning vs. flying spot laser technology on night vision and glare sensitivity.
- To assess visual performance in treated eyes compared to spectacle correction.
Main Methods:
- Three groups of 38 eyes each were studied: Group 1 (5.0mm scanning laser), Group 2 (6.5mm flying spot laser), and Group 3 (spectacle correction - control).
- All participants had 20/20 best spectacle-corrected visual acuity preoperatively.
- Mesopic vision and glare sensitivity were assessed using the Mesoptometer II at 12 months post-surgery.
Main Results:
- The flying spot laser with a 6.5mm treatment diameter (Group 2) achieved 85% success in night driving requirements, compared to 34% for the 5.0mm scanning laser (Group 1).
- Under glare conditions, 80% of eyes in Group 2 identified targets, versus 31.6% in Group 1.
- Control group (Group 3) showed the highest performance in both night driving (95%) and glare conditions (94.7%).
Conclusions:
- Unoperated eyes corrected with spectacles demonstrated superior mesopic function and contrast vision compared to excimer laser-treated eyes.
- A larger 6.5mm treatment diameter utilizing a flying spot laser system yielded better mesopic visual outcomes than a smaller 5.0mm diameter with scanning laser technology.
- The findings suggest that current excimer laser parameters may compromise mesopic visual quality.
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