OCT (OPTICAL COHERENCE TOMOGRAPHY) AS A DIAGNOSTIC TOOL IN CORNEAL DISORDERS

Abstract

Omkar Jagdish Telang1, Vrunda Gangadhar Morepatil2

BACKGROUND
OCT is an attractive modality for imaging the eye, because it can image both the anterior segment (cornea, angle, crystalline lens) and the posterior segment (retina) of the eye. OCT provides the cross-sectional retinal image in vivo. OCT has high image resolution (1-15 μm)1 and is capable of scanning a large area (up to 20 mm scan diameter). It perfectly fits the eye’s size. Our study included patients suffering from various corneal pathologies who underwent routine ophthalmic checkup followed by OCT. A detailed quantitative cross-sectional imaging of the cornea was obtained with regards to the localisation, size, shape, depth, texture and surface of corneal ulcer and infiltrates, extent of corneal oedema, depth of corneal opacity, surface and texture of graft-host junction in patients who underwent penetrating keratoplasty. The study was done to find out whether OCT could be valuable in the diagnosis and prognosis of corneal disorders keeping in mind the various studies conducted so far.
The aim of the study is to study the diagnostic and prognostic role of OCT in various corneal pathology.
MATERIALS AND METHODS
Study included 85 patients (males and females) visiting a tertiary healthcare centre with corneal pathologies diagnosed on slit-lamp biomicroscopy following which OCT was done over 2 years period (February 2014 to February 2016).
Design- Observational, cross-sectional, non-comparative study.
RESULTS
Corneal thickness is increased in corneal oedema (average 616 microns), while it is reduced in corneal ulcer (average 519 microns) and post keratoplasty patients (average 516 microns). The corneal thickness was normal in corneal degenerations (535 microns) and corneal opacity (545 microns). Texture was abnormal in 24 out of the 25 patients with corneal oedema. The corneal texture was abnormal in all 20 patients of corneal opacity and 18 out of 20 patients with corneal ulcer. All 5 patients post penetrating keratoplasty showed abnormal texture. Only 3 out of 15 patients with corneal degeneration showed abnormal texture. Depth assessment- Out of 20 patients with corneal ulcer, 12 were stromal and 8 were epithelial. Corneal surface was irregular in all 20 patients with corneal ulcer and 16 out of 20 cases of corneal opacity. In 8 patients of corneal oedema with bullous keratopathy, the corneal surface was irregular.
CONCLUSION
OCT provides objective documentation of corneal pathologies that cannot be provided by routine slit-lamp examination. Thus, OCT definitely plays an important role as far as the diagnosis and prognosis is concerned.

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