Abstract
Purpose :
To analyze the value of corneal epithelial thickness mapping (CETM) by Fourier-domain optical coherence tomography (OCT) in the diagnosis and differentiation of ocular surface pathologies involving the corneal epithelium.
Methods :
Study type:Cross-sectional.
Patients:Consecutive patients with ocular surface pathology involving the corneal epithelium who underwent CETM by Fourier-domain OCT at a tertiary center (Quinze-Vingts Hospital, Paris) were included.For each patient, CETM parameters were compared between the groups using Fisher-exact and one-way ANOVA tests in order to look for distinctive features for each pathology.
Results :
171 eyes of 171 patients were included between January 2013 and September 2015. Mean age at inclusion was 46.2 years. Patients distribution was as follows: 32.1% were healthy, 15.2% had limbal deficiency (LD), 7% had trachoma, 15.8% had epithelial basement membrane dystrophy (EBMD), 1.2% had herpes, 1.2% had dry eye syndrome, 20.5% had keratoconus (KC), 3% had Thygeson’s superficial punctuate keratitis, 1.8% had superior limbic keratoconjunctivitis and 1.8% had in situ carcinoma. Analysis of CETM revealed specific patterns for various pathologies. A “rayon de roue” aspect of CETM, corresponding to a circular succession of thickened and thinned epithelial areas, seemed specific of LD (72% versus 4% for LD versus all others respectively, p= 4e-8). “Pyramid” aspect of CETM involving triangularly thickened epithelium seemed specific of EBMD (74% versus 2%, p=2e-8). “Donut” aspect of CETM with temporally thickened epithelium, surrounding areas of thinned epithelium seemed suggestive of KC (34.3% versus 1.4%, p=6.4e-8). Other CETM parameters seemed distinctive of LD (LD versus all others respectively): minimal and maximal epithelial thicknesses (ET) (27.4 versus 44.3 microns for minimal ET and 77.4 versus 62.4 microns for maximal ET, p=0.0001), epithelium standard deviation (15.1 versus 4.24, p=0.01) and minimal-maximal ET (-49.9 versus -18.3 microns, p= 3.6e-8).
Conclusions :
CETM seems to differentiate ocular surface pathologies in a quite reliable manner. Specific epithelial patterns seem suggestive of LD, KC and EBMD. CETM can help characterize ocular surface pathologies that involve the corneal epithelium beyond what is apparent with the clinical examination, providing a non-invasive and easily available tool for diagnosis and monitoring.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.