Anterior Segment Optical Coherence Tomography for the Quantitative Evaluation of the Anterior Segment Following Boston Keratoprosthesis

Joann J Kang,Norma Allemann,Maria Soledad Cortina,Thasarat Vajaranant,Jose De La Cruz,Pedro Gonzalez

doi:10.1371/journal.pone.0070673

Joann J Kang, Norma Allemann + Show 4 more

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https://doi.org/10.1371/journal.pone.0070673

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Abstract

ObjectiveTo quantitatively evaluate the anterior segment using anterior segment optical coherence tomography (AS-OCT) following Boston keratoprosthesis type 1.MethodsA retrospective study consisted of AS-OCT imaging at a single time point postoperatively in 52 eyes. Main outcomes measures include anatomical and functional anterior chamber depth (ACD), angle (ACA) and peripheral and proximal synechiae.ResultsThe mean time point of imaging was 19.3 months postoperatively. Average anatomical and functional ACD was 2.0 and 0.21 mm respectively, and mean ACA ranged from 2.5° to 6.14° in representative meridians. An average of 8.7 clock hours of angle closure was observed in the 25 eyes in which all meridians were imaged. The majority of eyes showed peripheral (86.5%) and proximal (67.3%) synechiae.ConclusionsAS-OCT is a useful tool for quantitative evaluation of anterior segment and angle after keratoprosthesis, which is otherwise poorly visible. The majority of eyes showed shallow ACD, extensive angle closure and synechiae formation.

Highlights

The Boston keratoprosthesis (KPro) type 1 is an increasingly well-accepted surgical intervention for patients with severe corneal and ocular surface disease who are poor candidates for traditional penetrating keratoplasty (PKP)
Anterior segment imaging including ultrasound biomicroscopy (UBM) and anterior segment optical coherence tomography (ASOCT) has improved the evaluation of otherwise poorly visualized anterior chamber structures behind opacified corneas and implanted KPros. [3,4] UBM uses 35–50 MHz of high-frequency ultrasound waves to obtain images that can identify the anatomical characteristics of the anterior chamber and angle
There were a total of 49 patients of whom 33 were male and the mean age at time of surgery was 56.5 years

Summary

Introduction

The Boston keratoprosthesis (KPro) type 1 is an increasingly well-accepted surgical intervention for patients with severe corneal and ocular surface disease who are poor candidates for traditional penetrating keratoplasty (PKP). Visualization of the implanted Boston KPro, anterior segment and angle using conventional clinical examination techniques is limited; the interaction of KPro with surrounding anterior segment structures is not well understood. Anterior segment imaging including ultrasound biomicroscopy (UBM) and anterior segment optical coherence tomography (ASOCT) has improved the evaluation of otherwise poorly visualized anterior chamber structures behind opacified corneas and implanted KPros. [7] imaging of the implanted KPro by UBM is limited because the prosthesis material causes artifacts impairing the visualization of anterior segment anatomical details. [8] Infrared (1310 nm) radiation is used to provide real-time images and allows for qualitative and quantitative assessments of the anterior chamber and angle structures AS-OCT allows noninvasive, noncontact, highresolution cross-sectional imaging of the anterior segment. [8] Infrared (1310 nm) radiation is used to provide real-time images and allows for qualitative and quantitative assessments of the anterior chamber and angle structures

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