A comparison study of Optical Coherence Tomography Angiography Peripapillary Vessel Density in Early Glaucomatous and Normal Nigerian Eyes
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Keywords
Optical Coherence Tomography Angiography, Peripapillary Vessel Density, Early Glaucomatous Eyes
Abstract
Background: This study aimed to determine and compare the peripapillary vessel density (VD) in normal and early glaucomatous Nigerian eyes using Optical Coherence Tomography Angiography (OCTA), to provide evidence for the use of OCTA in enhancing the early diagnosis of glaucoma in Nigeria.
Methodology: This was a hospital-based cross-sectional comparative study of 90 early glaucomatous participants and 90 normal participants. Participants aged 40 and above, with open anterior chamber angles (Schaffer’s) on gonioscopy, vertical cup disc ratio (VCDR)>0.4 and Central Visual Field (CVF) Mean deviation (MD) less than -6 dB, with glaucoma hemifield test (GHT) outside normal limits on a reliable 24-2 perimetry (Humphrey Field analyser II, Zeiss Humphrey Matrix 715) were recruited as early glaucomatous while aged matched control with vertical cup disc ratio <0.4, intact neuro-retinal rims, healthy OCT determined RNFL thickness and GCC, and a normal visual field test results were recruited as normal participants. The participants had a complete anterior and posterior segment examination. One eye of each participant had OCTA scans. The average peripapillary Vascular density in each optic nerve head (ONH) quadrant was determined using Angiovue OCTA (Optovue Inc., Fremont, CA, USA). The relevant data were analysed using the Statistical Package for Social Sciences (SPSS) version 26 with statistical significance set at p<0.05 and 95 % confidence interval.
Results: The mean peripapillary VD was significantly reduced in the early glaucomatous eyes (50.21 ± 4.54) compared to the normal (54.60 ± 2.50) eyes (p <0.001). The peripapillary VD in the optic nerve head quadrants followed a similar trend of being lower in the early glaucomatous eyes (p<0.001).
Conclusion: The reduced peripapillary VD in early glaucoma denoted a reduction in ONH perfusion in early glaucoma, and highlighted the usefulness of OCTA peripapillary VD in the early diagnosis of glaucoma in Nigerian eyes.
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