Amnio-linking: Crosslinking with amniotic membrane in thin corneas

Abstract

Purpose : Limited therapeutic options exist for patients with keratoconus and low corneal thickness. We performed a prospective study in order to study the efficacy, stability, and visual acuity outcomes of the eyes of patients with thin corneas after amniotic membrane assisted corneal crosslinking.

Methods : A prospective study was carried out on 10 eyes from 9 patients, five females and four males, with diagnosis of keratoconus and corneal thicknesses below 380 µm. Their mean age was 32±7.3 years. Seven of the eyes (70%) were treated for keratoconus and two (20%) for post LASIK ectasia. Following corneal epithelium removal, cryopreserved amniotic membranes were applied. The total thickness of the cornea was evaluated with intraoperative optical coherence. Topographic data, specular microscopy, visual acuity, and refractive correction were recorded before the treatment and consecutively at each follow-up consultation during a period of 6 months. We analysed for differences in keratometry, pachymetry, visual acuity and endothelial cell count using Wilcoxon signed-rank tests between preoperative and 6-month follow-up visit values.

Results :
Average corneal thicknesses before and after amnio-linking were 343.33±20.91 and 355.11±17 respectively. Mean endothelial cell count was 2287±560.17 before surgery and 1657.4±674.78 after the procedure. Mean non-corrected visual acuity before crosslinking was 1.22±0.38 logMAR (approx. 20/200 Snellen), and after the procedure of 1.23±0.48, showing no significant differences (p = 0.779). No significant differences were observed regarding corrected visual acuity (p = 0.326), corneal thickness (p = 0.091), endothelial cell count (p = 0.080), Kmin (p = 0.176), Kmax (p = 0.310) or Kmean (p = 0.237).

Conclusions :
Amnio-linking appears to be an effective and stable technique for the treatment of patients with keratoconus who are not candidates for standard crosslinking procedures. Further studies are needed to establish this technique as an alternative for halting keratoconus progression.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.