Deep lamellar keratoplasty by intracorneal dissection: a prospective clinical and confocal microscopic study

To evaluate the clinical findings, visual outcomes, and confocal microscopic corneal features of a surgical technique for manual deep lamellar keratoplasty (DLKP) with intentional sparing of the most posterior stroma.

Noncomparative, prospective, 12-month interventional study.

Forty-six eyes of 45 patients who had corneal pathologic features without endothelial abnormalities and requiring corneal graft were treated by DLKP by manual stromal delamination. They were examined clinically after surgery and using in vivo confocal microscopy at 2 weeks and 1, 3, 6, and 12 months.

The surgical technique consisted of an intracorneal deep manual stromal dissection through a 4-mm limbal incision at 50 mum from Descemet's membrane (DM). After trephination, an endothelial free graft was sutured.

Topographic parameters, interface depth and reflectivity, and anterior and postinterface keratocyte density; visual acuity was correlated with these parameters.

Two eyes had rupture of the DM. Two eyes that had delayed epithelial healing because of graft override with stromal inflammation underwent a second surgery (penetrating keratoplasty). Mean uncorrected logarithm of the minimum angle of resolution (logMAR) uncorrected visual acuity and logMAR best-corrected visual acuity (BCVA) improved from preoperative values (1.342+/-0.239 and 0.923+/-0.226, respectively) to 0.421+/-0.122 and 0.104+/-0.068, respectively, at 12 months. Mean topographic astigmatism was 3.09+/-1.30 diopters (D) at 3 months after suture adjustment, and 2.87+/-0.92 D at 12 months after suture removal. Average interface depth was 64.2+/-6.7 microm at 15 days and showed no significant changes up to 12 months. Mean interface reflectivity was highest at 15 days (95.5+/-15.7 light reflectance units [LRU]) and showed a progressive decrease over time of 55.3+/-8.7 LRU at 12 months. A significant negative correlation was observed between BCVA and topographic astigmatism up to 1 month and between BCVA and interface reflectivity starting from 6 months after surgery.

Deep lamellar keratoplasty by intracorneal dissection provides visual and clinical results comparable with that of other DLKP techniques. Visual recovery is slow and progressive, taking up to 1 year. Confocal microscopy enables precise evaluation of corneal features, interface morphologic features, and reflectivity, demonstrating a negative correlation between interface reflectivity and BCVA showing that the progressive recovery over months of the interface transparency is correlated with the increase in visual acuity after 6 months.