Systemic and ocular determinants of mean ocular perfusion pressure in a population-based sample.

PURPOSE: To investigate the associations between mean ocular perfusion pressure (MOPP) and several variables including body mass index (BMI), comorbid medical conditions and various ocular parameters in a population-based sample. STUDY DESIGN: Cross-sectional. METHODS: Data of 2091 healthy participants from a previous population based cross-sectional study were reviewed. Inclusion criteria were adults ≥40 years of age who were screened on-site for glaucoma. Data on medical history, height, weight, systolic and diastolic blood pressures (SBP and DBP, respectively) were obtained. A basic ocular examination was performed which included intraocular pressure (Tono-Pen XL, Reichert Technologies) and central corneal thickness (Pacline pachymetry;) measurement, slit-lamp examination and non-mydriatic optic disc photography (nonmydα fundus camera, Kowa). MOPP was calculated using the formula [2/3 x (DBP + 1/3(SBP-DBP)]-IOP and low MOPP was defined as MOPP ≤45 mmHg. RESULTS: Mean age of the subjects was 63.04 ± 9.7 years (range: 44 and 99 years) and the majority were women (74.1%, n = 1549). Mean MOPP values in normal weight (BMI < 25), overweight (BMI = 25-29.9) and in obese individuals were 46.9 ± 9.0 mmHg, 48.6 ± 9.2 mmHg and 50.7 ± 10.0 mmHg, respectively (p < 0.001, in all pairwise comparisons). In the multivariable logistic regression analysis, migraine and IOP elevation (per 1 mmHg increment) were significantly associated with a low MOPP (OR: 2.10 and 1.22, p = 0.008 and < 0.001, respectively). On the other hand, risk of low MOPP was reduced in subjects with hypertension, and with increasing age (per 1-year increment) and BMI (per 1-unit increment) (OR: 0.15, 0.97, and 0.95, respectively, and p < 0.001 for all). CONCLUSION: Migraine and elevated IOP increase the risk of low MOPP and this may have a causal relationship with impaired optic nerve head blood flow.