The Iris Camera Corneal Opacification Measurements may be a Useful Tool for Determining Disease Progression

Abstract

Purpose : The iris camera is able to determine the clarity of the cornea andprevious studies carried out in Manchester have used the iris camera to study a group of patients with Mucopolysaccharidoses; a rare metabolic disease that causes a dysfunction in the breakdown of glycosaminoglycan by the lysosomal enzymes which causes cloudiness of the cornea due to the accumulation of these proteins in ocular tissues. Normally the level of haze in these patients is hard to measure but the iris camera gave accurate and repeatable measurements. In this study we aimed to determine if the iris camera would be a useful tool to follow the progression and treatment outcome in other diseases where corneal clouding occurs.

Methods : In a clinical based study, 120 participants with keratoconus and corneal dystrophies (85 males and 35 females, aged 18-79) and 65 normal controls (45 males and 20 females, aged 18-50) were assessed in the corneal clinic at the Manchester Royal Eye Hospital. The examination of participants was performed under standard lighting with no form of dilation. During images analysis, two pinpoint areas on the pupil close to the limbal margins were selected, one superiorly and the other inferiorly. The result of the analysis was known as the corneal opacification measure (COM) score gives an estimate of the level of opacity of the cornea. The COM score was compared to visual acuity and corneal thickness to assess correlation.

Results : COM score was significantly increased in both keratoconus and dystrophy while controls had score of absolute zero (0). Although both keratoconus and dystrophy exhibited COM scores, the latter had significantly higher scores (12) compared to keratoconus (1.6). A significantly lesser correlation was observed in keratoconus between the COM score, visual acuity and corneal thickness compared to dystrophy which showed positive correlations between these corneal thickness and visual acuity with p-values <0.05.

Conclusions : All diseased groups were associated with increased levels of COM scores compared to controls. Thus, further indicating the capacity of the iris camera to estimate and measure haze levels in various corneal diseases similar to other imaging techniques, but, its low cost and ease of use could make it a preferable alternative to existing instruments.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.