Assessment Of Glaucomatous Optic Disc Photographs By UK Optometrists

Abstract

 

Purpose:

 

To investigate the performance characteristics of UK optometrists when assessing stereoscopic optic disc photographs for the presence of glaucoma.

 

Methods:

 

An online survey, which included questions about qualifications, time in practice and practice environment, was initially completed by 1256 optometrists. Based on their responses, 208 (17%) were selected to undertake a further online disc assessment exercise. The optometrists viewed 110 stereoscopic disc image pairs (from Reus et al, Ophthalmology, 2010), of which 40 were healthy, 48 were glaucomatous, 6 were ocular hypertensive, and 16 were duplicates. The task was to indicate whether the disc appeared healthy or glaucomatous. Fifty-three participants had higher glaucoma qualifications.

 

Results:

 

Sensitivity and specificity were calculated for each participant and are shown in the figure, alongside the results from Reus et al, representing the performance of European ophthalmologists. Median sensitivity was 0.92 (IQR: 0.86 - 0.94) and median specificity was 0.74 (IQR: 0.68 - 0.8). Sensitivity was higher for UK optometrists than for European ophthalmologists (2-tailed t-test; p < 0.05) but specificity was lower for optometrists (2-tailed t-test; p <0.05 ). Agreement between optometrists was fair (Fleiss' Κ = 0.367). Practitioners with higher glaucoma qualifications did not have overall higher sensitivity than those without (1-tailed t-test; p = 0.4), but had higher specificity (1-tailed t-test; p = 0.002). There was no notable relationship between either performance characteristic and time since initial optometry qualification (all r² < 0.01).

 

Conclusions:

 

UK optometrists displayed high sensitivity and moderate specificity when assessing optic discs for the presence of glaucoma. Advanced glaucoma qualifications and the time since initial optometry qualification were not strong predictors of performance.  

 

Keywords: imaging/image analysis: clinical • optic nerve