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Visual performance following photoastigmatic refractive keratectomy: a prospective long-term study
1Stanford University School of Medicine, Stanford, California, USA.
Journal of Cataract and Refractive Surgery
|October 18, 2000
Summary
Excimer laser photoastigmatic refractive keratectomy (PARK) temporarily impacts visual performance, with full recovery by 12 months. Psychophysical assessments reveal early declines, but outcomes stabilize long-term.
Area of Science:
- Ophthalmology
- Refractive Surgery
- Visual Science
Background:
- Excimer laser photoastigmatic refractive keratectomy (PARK) is a surgical procedure to correct myopia and astigmatism.
- Long-term visual performance after PARK requires detailed evaluation using psychophysical methods.
Purpose of the Study:
- To prospectively assess the long-term effects of PARK on visual performance.
- To identify predictors of diminished visual performance post-PARK.
Main Methods:
- Prospective study of 93 eyes undergoing PARK for compound myopic astigmatism.
- Psychophysical assessments of contrast sensitivity and best spectacle-corrected visual performance at multiple time points up to 24 months.
- Evaluation under scotopic, photopic, and glare conditions.
Main Results:
- A transient decline in contrast sensitivity was observed post-PARK, particularly under photopic conditions at low spatial frequencies.
- Visual performance returned to preoperative levels by 12 months and remained stable up to 24 months.
- Higher attempted correction of spherical equivalent and astigmatism predicted poorer early scotopic visual performance.
Conclusions:
- Psychophysical assessments are sensitive indicators of visual performance changes after refractive surgery.
- PARK-induced visual deficits are temporary, resolving within 12 months.
- Spherical equivalent and astigmatic correction levels can influence early visual outcomes.