Wedge resection and lamellar dissection for pellucid marginal degeneration

To describe the use of crescentic corneal lamellar wedge resection and autolamellar dissection for the correction of pellucid marginal degeneration (PMD), and to assess its effectiveness in improving uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), astigmatism, corneal topography, and contact lens or spectacle tolerability.

The setting was a specialist referral corneal surgery center, United Kingdom. A retrospective review was performed of all patients who underwent a corneal wedge resection for PMD at our institutions. All patients had progressive deterioration of BCVA, increased astigmatism, and intolerance to contact lens wear. The irregular corneal shape with ectasia was detected clinically and confirmed by Orbscan tomography. A crescentic wedge of ectatic corneal tissue was excised in each case, the extent of which was judged both clinically and by Orbscan. Complete host deep lamellar dissection (limbus to limbus) was performed in 3 cases and partial host lamellar dissection in 3 cases to enable closure by mobilizing the host anterior lamellar cornea. Mersilene 10-0 (Ethicon, Somerville, NJ) sutures were used and adjusted to achieve a 90-degree shift in the axis of astigmatism.

Seven eyes of 6 patients had wedge resections performed by 1 surgeon (S.M.D.). The patients were followed for a mean of 10.7 months (SD, 9.2; range, 1-25 months). The eyes of patients with >1 month of follow-up had improved UCVA and BCVA. Four of 5 eyes of patients with >2 months of follow-up had a BCVA of 6/12 or better. Four patients were able to manage with improved visual acuity in spectacles, and 1 patient chose to wear contact lenses to achieve 6/7.5. One patient with only 6 months of follow-up had a UCVA of 6/7.5. The average reduction in keratometric cylinder for cases with >2 months of follow-up was 9.1 diopters (SD, 5.3; range, 3.1-16.3 diopters).

Corneal wedge resection with and without lamellar dissection is an effective surgical intervention for corneal ectasia in PMD and avoids allogeneic transplantation by way of a large penetrating or lamellar keratoplasty. The technique has a low intraoperative complication rate and gives improved UCVA, BCVA, keratometric cylinder, and spectacle or contact lens tolerance.