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Night vision testing in unoperated eyes
G J Florakis1, D A Jewelewicz, N I Fan
1Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA.
Journal of Refractive Surgery (Thorofare, N.J. : 1995)
|February 1, 1996
Summary
This study shows that the Night Vision Recording Chart can assess image quality issues after refractive surgery. It found that myopia worsens night vision degradation and astigmatism causes image displacement.
Area of Science:
- Ophthalmology
- Optometry
- Vision Science
Background:
- A previously developed test evaluates image degradation in patients post-photorefractive keratectomy (PRK) under scotopic conditions.
- Post-refractive surgery visual disturbances like corneal haze, decentration, and under-correction create identifiable patterns on the Night Vision Recording Chart.
Purpose of the Study:
- To evaluate night vision image degradation in various refractive error groups and contact lens wearers using the Night Vision Recording Chart.
- To assess the utility of the Night Vision Recording Chart in characterizing scotopic visual performance.
Main Methods:
- The Night Vision Recording Chart method was applied to 118 un-operated eyes (emmetropic, myopic, hyperopic, astigmatic) and 26 contact lens wearers.
- Image degradation patterns were analyzed under scotopic (low light) conditions.
Main Results:
- Scotopic image degradation was found to increase proportionally with the severity of myopic refractive error.
- Image displacement, a form of visual distortion, was observed to increase with astigmatism.
- Contact lens wearers exhibited greater night vision image degradation compared to spectacle correction.
Conclusions:
- The Night Vision Recording Chart provides a straightforward and reproducible method for quantifying image degradation under scotopic conditions.
- This tool aids in understanding and characterizing visual performance deficits in various ocular conditions and corrections.