Visual Impairment and Its Associated Factors Among Hypertensive Patients in Amhara Region Referral Hospitals, Ethiopia

Background

Visual impairment is one of the most common long-term effects of high blood pressure. It affects one's quality of life, independence, and mobility. There is a paucity of information regarding the prevalence of visual impairment due to hypertension in Ethiopia. Therefore, this study aimed to determine the prevalence of visual impairment and its associated factors among hypertensive patients in referral hospitals of the Amhara region, Ethiopia, 2021.

Methods

An institution-based cross-sectional study was conducted among 423 study participants, which were selected by systematic random sampling technique. Data were collected by using an interviewer-administered structured questionnaire and physical measurements. The collected data were entered into Epi-data version 4.6. Then, exported into SPSS Version 26 for analysis. The crude and adjusted odds ratios and 95% Confidence intervals were calculated. Both bivariable and multivariable logistic regression analyses were done. Variables with a p-value of ≤0.05 were stated as significantly associated with visual impairment.

Results

The overall prevalence of visual impairment among hypertensive patients was 32.4% (95% CI: 27.9-37.9). Duration of hypertension ≥ 5 years (AOR =3.06, 95% CI: 1.86-4.95), history of ocular trauma (AOR =2.50, 95% CI: 1.3-4.73), and ever alcohol drinking (AOR = 2.72, 95% CI: 1.32-5.62) were significantly associated with visual impairment.

Conclusion

Nearly one-third of hypertensive patients were visually impaired from the study participants. Duration of hypertension ≥5 years, history of ocular trauma, and ever alcohol drinking was significantly associated with visual impairment among hypertensive patients. Therefore, in addition to providing medical care and follow-up services for hypertension patients, health education is needed for early and proper management of visual impairment, and to decrease their level of alcohol consumption. Furthermore, better to do this study by prospective cohort study design to identify cause-and-effect relationships.

Diabetic brain or retina? Visual psychophysical performance in diabetic patients in relation to GABA levels in occipital cortex

Visual impairment is one of the most feared complications of Type 2 Diabetes Mellitus. Here, we aimed to investigate the role of occipital cortex γ-aminobutyric acid (GABA) as a predictor of visual performance in type 2 diabetes. 18 type 2 diabetes patients were included in a longitudinal prospective one-year study, as well as 22 healthy age-matched controls. We collected demographic data, HbA1C and used a novel set of visual psychophysical tests addressing color, achromatic luminance and speed discrimination in both groups. Psychophysical tests underwent dimension reduction with principle component analysis into three synthetic variables: speed, achromatic luminance and color discrimination. A MEGA-PRESS magnetic resonance brain spectroscopy sequence was used to measure occipital GABA levels in the type 2 diabetes group. Retinopathy grading and retinal microaneurysms counting were performed in the type 2 diabetes group for single-armed correlations. Speed discrimination thresholds were significantly higher in the type 2 diabetes group in both visits; mean difference (95% confidence interval), [0.86 (0.32-1.40) in the first visit, 0.74 (0.04-1.44) in the second visit]. GABA from the occipital cortex predicted speed and achromatic luminance discrimination thresholds within the same visit (r = 0.54 and 0.52; p = 0.02 and 0.03, respectively) in type 2 diabetes group. GABA from the occipital cortex also predicted speed discrimination thresholds one year later (r = 0.52; p = 0.03) in the type 2 diabetes group. Our results suggest that speed discrimination is impaired in type 2 diabetes and that occipital cortical GABA is a novel predictor of visual psychophysical performance independently from retinopathy grade, metabolic control or disease duration in the early stages of the disease.