Quality of Vision in Functioning Allografts After Deep Lamellar and Penetrating Corneal Transplantation

Abstract

Abstract: : Purpose: Visual acuity of patients with deep lamellar keratoplasty (DLK) has been shown to be similar to that of patients with penetrating keratoplasty (PK). This study aimed to investigate the optical quality of patients with deep lamellar corneal grafts and penetrating corneal grafts using visual acuity, contrast sensitivity and wavefront aberration. Since a high number of patients wear rigid gas permeable contact lenses after transplantation, a special interest was given to the optical quality with contact lenses. Methods: 23 patients (32 eyes) with unilateral or bilateral corneal grafts were included in this study. All patients underwent corneal transplantation for keratoconus and did not have any other ocular co–morbidity. All patients had sutures removed at least 3 months before the last examination. Visual acuity (Snellen charts), contrast sensitivity (Pelli–Robson charts) and higher order aberrations (HO) 2nd to 6th order (Wavescan® (Visx Inc.)) were performed and analyzed. Results: : Patients with penetrating corneal grafts had a significant better BCSVA with glasses or contact lenses than recipients of with deep lamellar grafts (p<0.0041). Subgroup analysis of DLK patients reviled that visual acuity of these patients was related to the amount of recipient corneal tissue remaining. Patients with a recipient corneal bed thickness of less than 20 microns had similar vision as patients with full thickness penetrating corneal grafts. Patients with a recipient bed thickness of more than 80 microns showed a significant drop in visual acuity with glasses or with contact lens (p=0.0033). There was no significant difference in higher order aberrations in terms of root mean square (RMS) or point spread function (PSF) between patients with PK or DLK. Sutures were significantly earlier removed after DLK compared to PK (8,5 months vs 13,9 months; p<0.0001) and the time of steroid application was significantly shorter for DLK than for PK patients (6,2 months vs 8,9 months; p=0.0067). Conclusions: DLK can result in similar visual quality in terms of snellen visual acuity, contrast sensitivity and higher order aberration compared to PK eyes. The main parameter for a good post–operative vision is the amount of recipient tissue left at the time of operation.

Keywords: keratoconus • transplantation • quality of life