Optic disc photographs exert little influence on optic disc measurements

J Glaucoma. 2011;20(4):207-210.

The use of optic disc photographs did not significantly enhance topographic measurement of optic disc morphology, a study found.

The study authors set out to evaluate measurement of optic disc morphology using Heidelberg Retinal Tomography (HRT) with and without optic disc photographs.

"The good agreement between the HRT parameters read with and without photographs suggests that in circumstances whereby photographs cannot be taken, the contour line may be read with photographic aids from HRT alone," the authors said. "Omitting the use of disc photographs in measuring HRT outputs may translate into significant savings in time and logistics in simultaneously obtaining HRT and optic disc photographs in large population-based studies."

The study included 103 children aged 11 and 12 years. Data were culled from the Singapore Cohort Study of Risk Factors for Myopia. Investigators used the HRT-II scanning laser ophthalmoscope to assess optic nerve head topography and retinal nerve fiber layer thickness.

One researcher drew contour lines with and without digital microscopic optic disc photographs. Statistical analyses were used to draw correlations between HRT measurements with and without optic disc photos.

Study results showed statistically significant intraclass correlations between almost all measurements (P = .001), except rim volume.

The highest intraclass correlations were for global maximum cup depth, global maximum contour elevation, global vertical cup-to-disc ratio and global horizontal cup-to-disc ratio, the authors reported.