Preliminary results with posterior lamellar keratoplasty for endothelial failure

Endothelial keratoplasty: clinical outcomes in the two years following deep lamellar endothelial keratoplasty (an American Ophthalmological Society thesis)

PURPOSE

To evaluate the clinical outcome of small-incision, deep lamellar endothelial keratoplasty (DLEK) for the treatment of endothelial dysfunction.

METHODS

A prospective series of 79 eyes that underwent DLEK by a single surgeon was evaluated. Best spectacle-corrected visual acuity (BSCVA), refractive astigmatism, and central endothelial cell density (ECD) were measured preoperatively and at 6, 12, and 24 months.

RESULTS

Data was available on 78 eyes (99%) at 6 months, 77 eyes (97%) at 1 year, and 79 eyes (100%) at 2 years. Mean BSCVA preoperatively of 20/71 improved to 20/42 by 6 months and remained stable. Eliminating eyes with known retinal disease, BSCVA of 20/40 or better was present in 60% (40 of 67) of eyes at 6 months, 74% (49 of 66) of eyes at 1 year, and 79% (53 of 68) of eyes at 2 years. Refractive astigmatism preoperatively was .91 +/-.78 diopters and was unchanged by surgery over time with results at 6 months of 1.11 +/-.76 (P = .052, power = .43), 1 year 1.04 +/-.80 (P =.287, power = .06), and 2 years 1.10 +/-.70 (P =.467, power = .22). The mean donor ECD preoperatively was 2819 +/- 225 (2389 to 3385) cells/mm(2), and this decreased by 26% at 6 months (2095 +/- 380) (1097 to 2920) (P = .0001; 95% confidence interval [CI] = 643-809), 3% fewer at 1 year (2009 +/- 393) (612 to 2723) (P = .054, power = .5), and 17% fewer at 2 years (1536 +/- 547) (500 to 2546) (P < .001, 95% CI = 368-585). Complications included one primary graft failure and 4 dislocations into the anterior chamber.

CONCLUSIONS

DLEK provides improved vision and minimal refractive astigmatic change, but progressive ECD decrease over time is of concern.

Lamelläre Keratoplastik

In 1840 Mühlbauer was the first to describe a technique for anterior lamellar keratoplasty (LKP). However, in the second half of the twentieth century penetrating keratoplasty (PKP) became the gold standard. Although it is associated with a higher risk for serious complications -- it is technically easier to perform and avoids wound healing reactions in the lamellar interface and thus resulting in better visual acuity. In view of the pathology, replacing all layers of the cornea including healthy parts can be considered therapeutic "overkill" for many corneal graft indications. Several innovative surgical techniques have recently been described which allow the lamellar dissection of recipient and donor cornea with good reproducibility in almost every desired depth. This now allows the recipient endothelium and Descemet's membrane to be selectively replaced or preserved and to avoid formation of an optical barrier in the lamellar interface in eyes undergoing lamellar keratoplasty for optical indications. The most important principal advantage of an anterior LKP -- to minimize the risk of an immune reaction in the graft -- is even more important in tectonic indications. From the large number of variations, the surgical technique, results, and problems with anterior and posterior LKP for optical indications as well as lamellar segment keratoplasty and epikeratoplasty for tectonic indications are discussed.