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DALK with dry manual dissection yields positive visual, refractive outcomes
Deep anterior lamellar keratoplasty using a dry manual dissection technique compared favorably with other deep lamellar methods, according to a study.
The retrospective study included 288 eyes of 268 patients who underwent DALK with a dry manual dissection technique. Patients with glaucoma, cataract, retinal disease, previous ocular surgery and amblyopia were excluded.
The dry manual dissection technique involved a deep corneal incision created with a calibrated diamond knife used as a guide to reach a pre-Descemetic plane. Ultrasonic pachymetry was used to gauge incision depth.
Visual acuity, topography, endothelial cell density and residual recipient stromal thickness were assessed at 2 months, 6 months, 1 year and 2 years postoperatively.
Study results showed that mean logMAR best corrected visual acuity was 0.131 and mean topographic astigmatism was 2.87 D at 2 years.
Perforation of Descemet’s membrane requiring conversion to penetrating keratoplasty occurred in 12 eyes (4.2%).
Mean residual recipient stromal thickness was 31.63 µm. Data showed a statistically significant correlation between lower residual recipient stromal thickness values and higher visual acuity (P < .001).
Intraoperative complications occurred in 22 eyes (7.6%), and postoperative complications occurred in 14 eyes (4.9%).
Perspective
Back to TopRama and colleagues describe a manual technique and analyze the results of patients undergoing DALK (deep anterior lamellar keratoplasty). The most common surgical technique for this procedure has been to use the “big bubble” as described by Anwar. Manual dissection of the stroma has been previously described, but the authors describe some modifications to this technique and provide a video demonstration. In this cohort of patients with the majority having keratoconus, the results are very favorable to PKP when the residual stroma was measured to be less than 20 microns. This study supports the notion that the less residual stromal bed, the best results will be obtained. If the big bubble technique can be achieved, the least amount of residual stroma is possible. Because this study was not able to directly compare this technique to a big bubble technique, it is not possible to determine which one will have the best outcomes. The video is very illustrative of how to do the technique.