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Shallow ablations in phototherapeutic keratectomy: long-term follow-up
Amy M M Chow1, Evan P F Yiu, M K Hui
1Department of Ophthalmology, Tuen Mun Hospital, Hospital Authority Ophthalmic Services, Hong Kong Special Administrative Region, China. avocado99@hotmail.com
Purpose:
To evaluate the long-term efficacy and safety of shallow ablations in phototherapeutic keratectomy (PTK) in patients with recurrent corneal erosions.
Setting:
Department of Ophthalmology, Tuen Mun Hospital, Hong Kong, China.
Methods:
A retrospective analysis of 13 consecutive eyes with recurrent corneal erosions treated by PTK from 1997 to 1999 was performed. All eyes failed to respond to conventional treatments, and all eyes had corneal erosions involving the visual axis. Outcome measures included number of recurrences, change in best corrected visual acuity (BCVA) and spherical equivalent (SE), and complications arising from the laser treatment.
Results:
Indications for PTK were recurrent corneal erosions secondary to minor abrasive trauma (9 eyes) and map-dot-fingerprint corneal dystrophy (4 eyes). The mean ablation depth was 4.6 microm (range 3.4 to 5.8 microm). Mean postoperative follow-up was 49.5 months (range 24 to 68 months). The overall success rate after only 1 treatment was 84.6%. Eleven of 13 eyes had a preserved or improved BCVA, while 2 eyes showed deterioration of 1 line on Snellen testing. Seven of 13 patients had no change in SE; the rest had a change of less than +/-0.50 diopters. There were no major complications.
Conclusions:
The comparable success rate after a single treatment suggests that PTK may still be effective at a shallower depth than previously considered. Shallow ablations may have lower chances of complications associated with deeper ablations. Further studies involving a larger number of subjects are warranted.
