In vivo morphologic characteristics of Salzmann nodular degeneration with ultra-high-resolution optical coherence tomography

Abstract

Purpose: To examine the in vivo morphologic properties of Salzmann nodular degeneration with ultra-high-resolution optical coherence tomography (OCT).

Design: Interventional case series.

Setting: Single-center academic practice.

Study population: Nineteen eyes of 12 patients with Salzmann nodular degeneration were recruited to participate in the study.

Observational procedure: Subjects were imaged using novel, custom-built ultra-high-resolution OCT. Images were used to describe in vivo characteristics of subepithelial nodules. Morphometric measurements were made with custom-built software. Ultra-high-resolution OCT findings were compared with histopathologic findings in 3 patients.

Main outcome measures: Identifiable in vivo morphologic characteristics of Salzmann nodular degeneration with ultra-high-resolution OCT.

Results: Ultra-high-resolution OCT images demonstrate intraepithelial fibrous nodules with epithelial thinning and corneal surface elevation. The Bowman layer could be differentiated in 9 of 12 patients. The difference between the mean thickness of epithelium above the nodule and the thickness of normal epithelium was statistically significant (P < .0001). The correlation between thickness of the epithelium and thickness of the nodule was statistically significant (r = -0.48; P < .0001). The correlation between thickness of the nodule and total surface thickness (thickness of the epithelium + thickness of the nodule) was statistically significant (r = 0.98; P < .0001). Ultra-high-resolution OCT findings were consistent with histopathologic results.

Conclusions: Ultra-high-resolution OCT can be used to noninvasively image the cornea in Salzmann nodular degeneration. This new imaging technique helps us to demonstrate different in vivo morphologic characteristics of Salzmann nodular degeneration.