LONG-TERM RESULTS OF CORNEAL WEDGE EXCISION FOR PELLUCID MARGINAL DEGENERATION

Purpose: A retrospective study reporting long-term visual and astigmat ic results of patients with pellucid marginal degeneration (PMD) treat ed by corneal wedge excision. Methods: The notes of 9 patients (10 eye s) treated by corneal wedge excision were reviewed, All patients had t ypical PMD and were treated by excision of an inferior crescent of dis eased corneal tissue. The excised area measured approximately 2 mm in width and extended from the 4 o'clock to the 8 o'clock meridian, All t hinned corneal tissue was removed, Normal-thickness corneal stroma was then reapposed with 10/0 nylon or 10/0 polypropylene sutures. Post-op erative selective suture removal was performed until a satisfactory vi sual and astigmatic result was achieved. This was guided by refraction , keratometry and photo-keratoscopy results. Pre-operative best correc ted visual acuity ranged from 6/12 to 6/60 with an associated mean ker atometric astigmatism of +13.8 dioptres (range 8-25 dioptres, axis ran ge 30 degrees-175 degrees). Mean follow-up was 59 months (range 14-138 months). Results: Post-operatively a stable corrected visual acuity o f 6/9 or better was achieved in all cases in a mean time of 5.4 months (range 3-12 months). Mean post-operative keratometric astigmatism was 1.4 dioptres (range 0.5-4 dioptres). Over the course of follow-up lon g-term astigmatic drift (LTAD) was noted, mean 2.1 dioptres (range 0.5 -5.5 dioptres). Three patients developed mild inferior pannus related to peripherally sited sutures, One case developed apparent corneal hyd rops within the corneal wound after 9 years of follow-up. Conclusions: We believe that corneal wedge excision offers an excellent surgical r esult for patients with PMD, although modification of the technique ma y be required to improve long-term astigmatic drift.