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Corneal haze after excimer laser refractive surgery: objective measurements and functional implications
C P Lohmann1, D S Gartry, M K Muir
1Institute of Ophthalmology, Department of Clinical Ophthalmology, London, U.K.
European Journal of Ophthalmology
|October 1, 1991
Summary
Postoperative photorefractive keratectomy (PRK) can affect corneal transparency and visual acuity. Studies show temporary visual disturbances, particularly in low contrast, typically resolving within four months after PRK.
Area of Science:
- Ophthalmology
- Corneal Surgery
- Visual Optics
Background:
- Corneal transparency changes post-photorefractive keratectomy (PRK) are a significant concern.
- Objective measurement of these changes and their impact on vision is crucial.
Purpose of the Study:
- To evaluate the relationship between objective corneal transparency measurements and visual performance after PRK.
- To understand the temporal dynamics of corneal light scattering and reflection post-PRK.
Main Methods:
- Utilized a CCD-camera device with polarizing filters to differentiate reflected and scattered light in 69 human eyes post-PRK.
- Monitored corneal transparency signals and visual acuity (5% contrast) over time.
Main Results:
- Two distinct postoperative transparency patterns were observed.
- Scattered light correlated well with reduced low contrast visual acuity, peaking around two months and improving by four months.
- Reflected light showed a biphasic curve, with less correlation to visual performance.
Conclusions:
- PRK is effective, with temporary corneal transparency disturbances impacting vision primarily in the first 3-4 months.
- Scattered light is a key indicator of visual performance changes post-PRK.
- Most patients regain preoperative visual function within four months.