2020 Scholarship recipient Aqeeda Singh outlines her project working with the Dunedin Study. This world-renowned longitudinal study has been following the lives of 1037 babies born in the greater Dunedin metropolitan area between 1 April 1972 and 31 March 1973 to understand the factors leading to significant health and social outcomes in life. These participants have been interviewed, examined and investigated in numerous ways throughout their lives, with a very high follow-up rate of 94% at 45 years of age.
Now in middle age, the participants were recently subject to a broad range of tests relating to their eyes, including intraocular pressure (IOP), retinal photography, optical coherence tomography (OCT) and visual field testing; this study has examined their eye-related data to measure the prevalence of glaucoma in this cohort.
This is one of the first population-based studies of glaucoma prevalence using modern OCT scans to determine a diagnosis of early glaucoma (when visual fields are normal) and has implications for public health planning in New Zealand.
Two independent ophthalmologists examine the optic disc photographs, masked to other data, and then suspicious discs were re-examined with more information such as IOP, corneal thickness, OCT and visual fields.
The prevalence amongst 45-year- olds was 0.79%, in line with other populations. At this age, the prevalence was low, so it was impossible to ascertain risk factors or undertake subgroup analyses such as risk by ethnicity. Interestingly, those with raised IOP had a low rate of glaucoma; nearly all of the cases we found had normal IOP. None of the glaucoma cases had significant visual field loss, so these are mild early cases.
Aqeeda said, “We are interested in modelling how the use of OCT at a population level detects many low-risk glaucoma suspect cases, generating a new burden for monitoring to prevent rare cases of vision loss”. She is grateful to Prof Helen Danesh-Meyer for the support and direction with this project, as well as the Gordon Sanderson Scholarship committee and Glaucoma NZ.