Purchase this article with an account.
Ross Thomas Aitchison, Graeme J Kennedy, Xinhua Shu, David C Mansfield, Uma Shahani; Measuring central macular thickness in diabetes using swept-source OCT. Invest. Ophthalmol. Vis. Sci. 2019;60(9):2615.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Diabetic macular oedema (DMO) is characterised by retinal thickening in the macular region. DMO is the most frequent cause of sight impairment in individuals with diabetes mellitus. Non-invasive imaging techniques of the retina, such as optical coherence tomography (OCT), are useful in the diagnosis of DMO. The latest generation of this technology, swept-source OCT (SS-OCT), permits an increased depth of imaging. The purpose of this study was to use SS-OCT to measure the central macular thickness (CMT) in diabetic and non-diabetic individuals.
3D Macula (7mm x 7mm) scans of both eyes were taken using SS-OCT (Triton, Topcon, Tokyo). CMT was automatically calculated by proprietary software at the intersection of the radial scans that comprised the 3D Macula scan.Participants’ glycated haemoglobin (HbA1c) levels were measured using the A1cNow+ System (PTS Diagnostics, Indianapolis, IN). HbA1c is the gold-standard method used to assess three-month average glycaemic control.The diabetic (n=27) and control (n=27) groups were matched for age (p=0.100) and gender (p=0.276). The mean HbA1c level (±SD) was 7.5±0.8% in the diabetic group and 5.4±0.4% in the non-diabetic group, and this differed between groups (p<0.0005). All participants had a best-corrected visual acuity of 0.3 logMAR or better in each eye, and diabetic individuals had no previous diagnosis of DMO.
Inter-ocular measures of CMT were similar using intra-class correlation analysis; therefore, an average CMT value was used. Diabetic individuals had a significantly higher CMT than their non-diabetic counterparts (p<0.005). The mean (±SD) CMT was 213±28μm in the diabetic group and 190±14μm in the non-diabetic group. Linear regression analysis was used to assess the effect of HbA1c level on CMT. In diabetic individuals, HbA1c level statistically significantly predicted CMT (F1,25=5.782, p=0.024, R2=0.189). HbA1c thus accounted for 18.9% of the variation in CMT.
SS-OCT is a useful method to quantify CMT. Using this technology, we have found that diabetic individuals have a higher CMT than non-diabetic individuals. In diabetic individuals, CMT appears to be correlated with glycaemic control. Our results suggest that, in diabetes, sub-clinical changes may occur in the macular region, prior to DMO becoming clinically evident. Maintenance of good glycaemic control may improve macular haemodynamics and, therefore, may reduce the incidence of DMO.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
This PDF is available to Subscribers Only