Long-Term Anatomical and Functional Survival of Boston Type 1 Keratoprosthesis in Congenital Aniridia.

Ariann Dyer,Rafael I Barraquer,Juan Álvarez De Toledo,Gemma Julio,Alix De Faria,Maria Fideliz De La Paz

doi:10.3389/fmed.2021.749063

Abstract

Purpose: To analyze the long-term anatomical survival, functional survival, and complications of Boston type 1 keratoprosthesis (KPro) in the eyes with congenital aniridia-associated keratopathy (AAK).Methods: A retrospective review of 12 eyes with congenital aniridia that underwent a Boston type 1 KPro surgery was conducted. A Kaplan–Meier analysis was performed. Anatomical and functional success criteria were KPro retention and a best corrected visual acuity (BCVA) ≤1.3 LogMAR (≥0.05 decimal) at the end of a follow-up period. Postoperative complications were recorded.Results: The mean preoperative BCVA was 2.1 ± 0.9 (range: 3.8–1) LogMAR, and glaucoma was a comorbidity in all the cases. Five years after the surgery, the overall retention rate was 10/12 (83.3%), and 50% had functional success. Only three (25%) of the 12 cases did not achieve a BCVA ≤1.3 LogMAR. The cumulative probability of anatomical success was 92, 79, and 79% after 1, 5, and 10 years, respectively. The cumulative probability of functional success was 57 and 46% after 1 and 5 years, respectively. The mean anatomical and functional survival time was 10 ± 1.3 (95% IC = 7.5–12.3 years) and 3.8 ± 0.9 years (95% IC = 1.8–5.8 years), respectively. The most common postoperative complication was retroprosthetic membrane (RPM) formation in 8/16 cases (66%). The mean number of complications per case was 2.4 ± 1.8 (0–6).Conclusions: The Boston type 1 KPro is a viable option for patients with AAK with good anatomical and functional long-term results. Glaucoma is an important preoperative condition that affects functional results. Retroprosthetic membrane formation seems to have a higher incidence in this condition.

Highlights

Congenital aniridia is a rare condition that affects 1/64,000 to 96,000 live births and has a major impact on vision and, quality of life (1)
Aniridia-associated keratopathy is characterized by limbal stem cell deficiency, which causes progressive vascular pannus, corneal conjunctivalization, recurrent epithelial erosions, and subepithelial fibrosis, eventually leading to corneal opacification (2)
The Boston type 1 Kpro was a primary indication in seven eyes (58%), and the secondary Boston type 1 Kpro was performed in five eyes (42%), which had undergone previous penetrating keratoplasty (PK) that, in some cases, had multiple failed

Summary

Introduction

Congenital aniridia is a rare condition that affects 1/64,000 to 96,000 live births and has a major impact on vision and, quality of life (1). Boston Kpro in Congenital Aniridia and optic nerve hypoplasia, aniridia-associated keratopathy (AAK), and nystagmus (3). It is associated with mutations in the PAX6 gene. AAK is the most common cause of progressive vision loss, and it can present as early as the first decade of life; the median age of diagnosis is 33 years old (4). Aniridia-associated keratopathy is characterized by limbal stem cell deficiency, which causes progressive vascular pannus, corneal conjunctivalization, recurrent epithelial erosions, and subepithelial fibrosis, eventually leading to corneal opacification (2). Because of limbal cell deficiency, penetrating keratoplasty (PK) is usually unsuccessful in the long term, and keratolimbal allografts with or without subsequent PK may be a better alternative; aggressive long-term systemic immunosuppression is required (2, 6)

Objectives

Methods

Results

Conclusion