The correlation between BMI and intraocular pressure, retinal nerve fiber layer thickness, and retinal microvasculature: a comparative optical coherence tomography angiography/perimetry study

Purpose To study the microvascular retinal changes in overweight and obese Egyptians relative to normal by optical coherence tomography angiography (OCTA) and to correlate them to BMI to intraocular pressure (IOP), perimetry, and retinal nerve fiber layer (RNFL) thickness. Patients and methods A tertiary-center study included 180 patients, categorized to three groups based on their BMI. Group 1 (healthy): patients with BMI 18.5–24.9. Group 2 (overweight): patients with BMI 25.0–29.9. Group 3 (obese): patients with BMI more than 30. Measurement of blood pressure, both systolic and diastolic. Lipid profile (triglycerides and total cholesterol) and serum creatinine. And will have a full ocular examination including IOP measurement by Goldmann applanation tonometry and performed two investigations: OCTA macula and disc by SD-OCT (Optovue Avanti 6000101-901-0300) and Zeiss Automated Humphrey (850-10033) perimetry with Swedish interactive thresholding algorithm (SITA) standard 24-2. Results IOP showed lower significant results in groups 1 and 2 than those in group 3 with a mean of 14.98±1.44, 15.27±1.30, 16.30±1.44 mmHg successively in the groups. No significant differences between the three groups in temporal, nasal, superior, inferior, and average RNFL thicknesses and in ganglion cell complex thicknesses and mean deviation, VF%, and pattern standard deviation differed insignificantly between the groups 1 and 2, while it is lower in group 1 in comparison to groups 2 and 3. Foveal avascular zone and foveal avascular zone perimeter measurements did not differ significantly between groups. Retinal superficial and deep capillary plexus and radial peripapillary capillary vessel density showed lower readings in obese and overweight relative to normal. Conclusion Retinal and disc microvascular obesity-related changes may precede both structural and functional alterations in macula and RNFL.