Abstract
Purpose :
Central and epithelial thicknesses of keratoconic (KC) corneae have been recently measured with optical coherence tomography and histology. The purpose of this study was to characterize the central and peripheral morphology KC corneae (ex-vivo) and correlate morphological patterns with their clinical history.
Methods :
Ex-vivo histological imaging was performed to measure epithelial and total corneal thickness. The clinical histories and microscopic slides of 56 patients with KC were studied. The paraffin blocks were retrieved, sectioned in 5-µm-thick sections and stained with hematoxylin and eosin (H&E) and evaluated using bright field microscopy. Central and peripheral epithelial thickness were measured, and morphological features were studied in order to identify differences and possible patterns of alteration that were previously noted by the authors. Clinical history regarding duration of KC prior to surgery and length of and tolerance to contact lens wear were compared and analysed to find if a relationship was present with the pattern type.
Results :
Of the 56, 48 were analysed. The epithelial and total thicknesses of the central and peripheral corneae were measured and divided into 3 patterns types. Centrally, the thickened (hypertrophic and hydropic) epithelium thickness (pattern 1, n=19) was 70.89±25.88 µm and the total thickness was 308.63±100.74 µm; 36.5±7.02 µm and 260.14±87.93 µm with pattern 2, having hyperplastic and focal hydropic changes (n=14), respectively; 19.93±4.60 µm and 268.00±79.39 µm with pattern 3, having atrophy and atrophy with focal swelling (n=15), respectively. The peripheral epithelium and total thicknesses were not significantly difference comparing the 3 patterns. The results of central epithelial thickness (CET) were significantly different comparing each pattern (p<0.0001). Significant changes in CET having pattern 2 was correlated only with the duration of the condition (p=0.03). There was a significant difference in the length of CL wear comparing those with patterns 1 and 2 versus 3 (least no. of CL years) (p=0.05 and p=0.33 resp.).
Conclusions :
These patients with advanced disease have various central corneal epithelial changes that can be detected with histology. Although each central epithelial pattern type was distinctive comparing the 3 patterns, there was no correlation with years of CL wear but only with the duration of the condition.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.