METHODS: A comparative cross-sectional study was conducted among children with T1DM and healthy children aged 7 to 17 years old in Hospital Universiti Sains Malaysia from 2017 to 2019. Children with retinal disease or glaucoma were excluded. Macular and RNFL thicknesses were measured using spectral-domain optical coherence tomography. Demographic information, duration of diabetes, blood pressure, body mass index, visual acuity, and retinal examination findings were documented. Glycosylated hemoglobin levels, renal function, and blood lipid levels were also collected.
RESULTS: Forty-one children with T1DM and 80 age- and sex-matched children were enrolled. Both sexes were affected. Mean duration of diabetes mellitus was 3.66 years. The mean glycated hemoglobin levels in the T1DM group was 9.99%. The mean macular and RNFL thicknesses in children with T1DM were 277.56 (15.82) µm and 98.85 (12.05) µm, respectively. Children with T1DM had a significantly thinner average macula, superior outer macula, nasal outer macula, mean RNFL, and inferior RNFL thickness compared to controls (p < 0.05). There was a significant association between nephropathy and the mean RNFL thickness.
CONCLUSIONS: Children with T1DM had significantly decreased mean macular and RNFL thicknesses. Nephropathy is associated with an increased RNFL thickness.
METHODS: Cross sectional observational cohort study. Subjects with normal eyes were recruited. Two sets of optical coherence tomography angiography images of macula and optic nerve head were acquired during one visit. Novel in-house developed software was used to count the pixels in each images and to compute the microvessel density of the macula and optic disc. Data were analysed to determine the measurement repeatability.
RESULTS: A total of 176 eyes from 88 consecutive normal subjects were recruited. For macular images, the mean vessel density at superficial retina, deep retina, outer retina and choriocapillaries segment was OD 0.113 and OS 0.111, OD 0.239 and OS 0.230, OD 0.179 and OS 0.164, OD 0.237 and OS 0.215 respectively. For optic disc images, mean vessel density at vitreoretinal interface, radial peripapillary capillary, superficial nerve head and disc segment at the level of choroid were OD 0.084 and OS 0.085, OD 0.140 and OS 0.138, OD 0.216 and OS 0.209, OD 0.227 and OS 0.236 respectively. The measurement repeatability tests showed that the coefficient of variation of macular scans, for right and left eyes, ranged from 6.4 to 31.1% and 5.3 to 59.4%. Likewise, the coefficient of variation of optic disc scans, for right and left eyes, ranged from 14.3 to 77.4% and 13.5 to 75.3%.
CONCLUSIONS: Optical coherence tomography angiography is a useful modality to visualise the microvasculature plexus of macula and optic nerve head. The vessel density measurement of macular scan by mean of optical coherence tomography angiography demonstrated good repeatability. The optic disc scan, on the other hand, showed a higher coefficient of variation indicating a lower measurement repeatability than macular scan. Interpretation of optical coherence tomography angiography should take into account test-retest repeatability of the imaging system.
TRIAL REGISTRATION: National Healthcare Group Domain Specific Review Board ( NHG DSRB ) Singapore. DSRB Reference: 2015/00301.