Abstract
BackgroundAccumulation of multiple pockets of fluid at the fovea, as a complication of poor blood glucose control in diabetes, causes impairment of central vision. A new ability to demonstrate a pre-clinical phase of this maculopathy could be valuable, enabling diabetic individuals to be alerted to the need to improve their glycaemic control. This study aimed to use swept-source optical coherence tomography (SS-OCT) to measure foveal thickness and macular volume in diabetic individuals without cystoid macular oedema, and in non-diabetic individuals, and relate these measures to participants’ glycaemic control.MethodsCentre point thickness (CPT) and total macular volume (TMV) were measured using SS-OCT (DRI OCT Triton™, Topcon, Tokyo, Japan). Participants’ glycosylated haemoglobin (HbA1c) level was also assessed (A1cNow®+ System, PTS Diagnostics, Indianapolis, IN, USA). The diabetic (n = 27) and non-diabetic (n = 27) groups were matched for age (p = 0.100) and sex (p = 0.414), and HbA1c level differed between diabetic and non-diabetic groups (p < 0.0005). The diabetic group comprised type 1 (n = 7) and type 2 (n = 20) diabetic individuals who were matched for duration of diabetes (p = 0.617) and whose glycaemic control was similar (p = 0.814).ResultsDiabetic individuals had significantly higher CPT (t(37) = 3.859, p < 0.0005) than non-diabetic individuals. In the diabetic group, multiple linear regression analysis revealed a conspicuous relationship between CPT and HbA1c level (β = 0.501, t(21) = 3.139, p = 0.005): there was a 19-μm increase in CPT for each 1% increase in HbA1c level. This relationship was not present in the non-diabetic group (β = − 0.068, t(23) = − 0.373, p = 0.712).ConclusionsSS-OCT is the only way to measure macular thickness in vivo. Diabetic individuals en bloc had higher CPT compared with non-diabetic individuals. Moreover, in the diabetic group, HbA1c level significantly predicted CPT. Our results suggest that, in diabetes, sub-clinical thickening may occur at the fovea before cystoid macular oedema becomes clinically evident. This could provide diabetic individuals with an early warning of disease progression and motivate them to improve control of their diabetes, with a view to avoiding the need of intra-vitreal injections with their attendant risks.
Highlights
Diabetic cystoid macular oedema (DCMO), which is characterised by multiple pockets of fluid at the fovea, is the leading cause of visual impairment in people of working age [1]
Using intra-class correlation analysis, we found that measures of Centre point thickness (CPT) and total macular volume (TMV) that were obtained from participants’ right and left eyes were similar (Table 1)
In accordance with statistical guidelines for data obtained from two eyes [23, 24], because there was a significant inter-ocular relationship for CPT and TMV above parameters, we used the mean value of the right and left eyes for each participant
Summary
Diabetic cystoid macular oedema (DCMO), which is characterised by multiple pockets of fluid at the fovea, is the leading cause of visual impairment in people of working age [1]. It is a complication of poor blood glucose control in diabetes and has a prevalence of 6.8% in the diabetic population [2]. Glycosylated haemoglobin (HbA1c) is the gold-standard method used to assess long-term glycaemic control. Accumulation of multiple pockets of fluid at the fovea, as a complication of poor blood glucose control in diabetes, causes impairment of central vision. This study aimed to use swept-source optical coherence tomography (SS-OCT) to measure foveal thickness and macular volume in diabetic individuals without cystoid macular oedema, and in non-diabetic individuals, and relate these measures to participants’ glycaemic control
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
