Author: Piyali Sen (United Kingdom)
Co-authors: Sarega Gurudas, Akanksha Bagchi, Sridevi Thottarath, Deepthy Mennon, Sudha Rajan, Sobha Sivaprasad
Purpose
The main aim of the study was to assess age, gender and ethnic variation in foveal avascular zone morphology and explore whether such changes correlate with differences in retinal thickness.
Setting/Venue
Patients attending the medical retina clinics at Moorfields Eye Hospital City Road, London with at least one healthy eye who had optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) performed on the same day in between September 2016 to December 2018 were included in the study.
Methods
Retrospective observational study. Healthy eye of participants aged 20 years and above from White, Afro-Caribbean, or South Asian ethnic background were imaged using spectral domain optical coherence tomography (SD OCT) and Angioplex OCT angiogram. Macular angiometrics for superficial capillary plexus was compared between ethnic groups. Correlation between retinal thickness and OCTA parameters were assessed using Pearson’s or Spearman’s coefficient. Regression analysis was performed to assess the statistical significance of age, sex on macular thickness and OCTA parameters in each of the three ethnic groups. All statistical tests were two tailed (α=0.05) and a p-value less than 0.05 was considered statistically significant.
Results
Among 110 individuals included in the study 47 were Whites, 30 Afro-Caribbean and 33 Asians. The study sample consisted of 68 males and 42 females. The mean age ± Standard Deviation of the Whites were 62.36±12.21 years, 56.47±11.36 years in Afro-Caribbean and 56.39±13.82 years in Asian. The central SVD was significantly lesser in Afro-Caribbean (9.06±3.76 vs 11.26±3.82, p=0.02) and South-Asian (9.04±3.44 vs 11.26±3.82, p=0.009) compared to Whites. The FAZ circularity was similar in the 3 groups. Compared to the Whites, the FAZ area and FAZ perimeter were both significantly larger in Afro-Caribbean (area p=0.001, perimeter p=0.006) and Asian groups (area p<0.001, perimeter p<0.001). Macular thickness in the innermost 1mm ETDRS zone (CST) was significantly lesser in Afro-Caribbean (268.40±31.65 vs 283.44±28.42, p=0.03) and South-Asian (263.21±40.33 vs 283.44±28.42, p=0.01) compared to Whites. Although the FAZ area in females was slightly higher than in males. None of the imaging markers reached statistical significance. FAZ area and perimeter are negatively correlated with central subfield thickness (CST) for whole cohort and among individual ethnic groups. Positive correlation was observed between SVD centre and CST(p<0.01). In age adjusted analysis, CST, superficial central vessel density, FAZ area and perimeter maintained statistical significance like initial unadjusted analysis.
Conlusions
Our study show Caucasians have higher retinal thickness and superficial capillary vessel density with relatively smaller FAZ area and perimeter compared to the Afro- Caribbeans and Asians. However, these parameters were not significantly different when Afro- Caribbeans were compared with Asians. These observations hold true even after age adjustment, although not so when adjusted for sex. Our results also suggest CST is negatively correlated with FAZ area and perimeter while a positive correlation exist between retinal thickness and vessel density of individual sectors of ETDRS recommended 3mm inner ring.
Financial Disclosure
No financial interest
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