Quantum of Corneal Scarring Calculation by Image Analysis of Anterior Segment OCT Images

Anterior Segment OCT is a valuable tool in providing B scan images of the cornea and anterior segment of the eye. Corneal scarring is a residue of various ocular diseases which include corneal ulcers, trauma and dystrophies. Corneal scarring results in corneal blindness and severe visual disability for the affected patient. Current grades of assessing corneal scarring are purely qualitative in nature. Though these clinical grades (nebula, macula, leucoma) are useful in guiding clinicians in making clinical decisions regarding treatment, they lack precision because of the absence of numeric data. Experimental research involving corneal scarring would greatly benefit from quantitative methods which are amenable to statistical analysis. Purpose: To determine the quantum of corneal scarring by image analysis of Anterior Segment Optical Coherence Tomographic (AS-OCT) vertical and horizontal scans of both the scarred and normal corneas of 32 subjects. Methods: Image processing and pixel analysis of the vertical and horizontal AS-OCT scans were done in the normal and scarred eyes to determine the mean pixel intensity, corneal thickness and quantum of corneal scarring. Results: The mean pixel intensity for scarred corneas was determined to be 126.2 for horizontal and 136.17 for vertical and 100.09 for horizontal, 96.75 for vertical on the normal corneas. The mean corneal thickness on scarred eyes was 204.46 and 217.38 for horizontal and vertical. Whereas on the normal corneas was 202.78 and 201.09 for horizontal and vertical. Quantum of variability for the scarred eyes was 26.11 and 39.42 for horizontal and vertical, respectively. The differences in medians of quantums of three scarred groups were statistically significant.