Frequency-doubling perimetry after photorefractive keratectomy.

PURPOSE: To evaluate the effect of photorefractive keratectomy (PRK) on frequency-doubling perimetry (FDP) patterns in myopic patients without glaucoma.

SETTING

Department of Ophthalmology, University of Bari, Bari, Italy.

METHODS

Sixteen myopic patients (16 eyes) with a spherical equivalent worse than -7.0 diopters were enrolled. The fellow eyes were used as controls. All patients had PRK for myopia. Using FDP, the mean defect (MD) and pattern standard deviation (PSD) were evaluated preoperatively and 2 weeks and 3 and 6 months after PRK. At the same examinations, the effect of the reprofiled cornea on the visual field was studied; the cornea was divided into 4 concentric zones (central, paracentral, lateral, and peripheral) and each median zone contrast sensitivity (MZCS) evaluated.

RESULTS

There was no difference in PSD and MZCS between treated eyes and controls in any zone at any time (P >.05). Longitudinally, there was no variation in any perimetry zone (P >.05). In treated eyes, there was a significant relationship among ablation depth, MD, and MZCS in all zones until 2 weeks after laser surgery (P <.02).

CONCLUSIONS

Frequency-doubling perimetry did not appear to be affected by corneal changes induced by PRK and can therefore be safely used in the early diagnosis of glaucoma.