**Background:** Dry eye (DE) is a common tear film disorder that causes ocular discomfort and can significantly impair quality of life. Its prevalence increases with age, and it is often associated with obesity and hypertension. Current medical treatments for DE are often unsatisfactory, prompting interest in lifestyle modifications as complementary therapies. This study aimed to investigate the effects of a 6-month high-intensity interval aerobic exercise (HIIAE) program, alone or combined with a Mediterranean diet (MD), on DE parameters in obese hypertensive elderly individuals.
**Methods:** This was a single-blinded, prospective, randomized controlled trial conducted from January to December 2022. Sixty obese hypertensive elderly patients (≥65 years) with DE were recruited from the ophthalmology outpatient clinic of Cairo University hospitals. Participants were randomly assigned to an experimental group (n=30) receiving HIIAE plus MD, or a control group (n=30) receiving HIIAE alone. HIIAE consisted of 30-minute sessions on an electronic bicycle, 3 times per week, including warm-up, 7 cycles of 2-minute high-intensity intervals (90% of maximal heart rate) interspersed with 1-minute active rest (60% of maximal heart rate), and cool-down. The MD protocol was based on Bedard et al. (2012) and included specific weekly and daily servings of olive oil, cereals, fruits, vegetables, eggs, legumes, nuts, fish, poultry, and low-fat dairy, with a calorie restriction of about 15% from daily requirements (2000 kcal/day for men, 1600 kcal/day for women). Assessments at baseline and after 6 months included anthropometry (weight, BMI, abdominal circumference), blood pressure (systolic and diastolic), and DE parameters: tear film break-up time (TBUT), dry eye scoring system (DESS), ocular surface disease index (OSDI) questionnaire, Schirmer's test, and Oxford grading system (OGS). Statistical analysis used two-way MANOVA, Tukey post-hoc tests, and non-parametric tests for OGS.
**Key Results:** Both groups showed significant improvements, but the experimental group (HIIAE+MD) demonstrated significantly greater improvements than the control group (HIIAE alone) in most outcomes. For anthropometry and blood pressure, the mean differences (MD) in the experimental vs. control group were: weight (10.03 vs. 5.33 kg), BMI (3.46 vs. 1.9 kg/m²), abdominal circumference (10.13 vs. 6.3 cm), systolic blood pressure (6.53 vs. 4.13 mmHg), and diastolic blood pressure (8.03 vs. 3.8 mmHg). All between-group differences were statistically significant (p<0.05). For DE parameters in the right eye, the experimental vs. control group showed: DESS (MD 0.81 vs. 0.3), OSDI (MD 5.6 vs. 4.2), TBUT (MD -1.43 vs. -0.58 seconds), Schirmer's test (MD -1.38 vs. -0.56 mm), and OGS (MD 0.04 vs. 0.01). Between-group differences were significant for all DE parameters except OGS (p=0.53 for right eye, p=0.69 for left eye). Similar results were observed for the left eye. The MANOVA analysis showed significant effects for group (Wilks' λ=0.42, f=6.73, p=0.001, η²=0.58), time (λ=0.02, f=213.97, p=0.0001, η²=0.97), and the interaction (λ=0.14, f=29.95, p=0.0001, η²=0.85).
**Clinical Implications:** This study provides evidence that a 6-month HIIAE program can significantly improve DE symptoms and signs in obese hypertensive elderly, and that combining exercise with a Mediterranean diet yields even greater benefits. The improvements in tear film stability (TBUT), tear production (Schirmer's test), and subjective symptoms (DESS, OSDI) suggest that lifestyle modification may be an effective complementary treatment for DE. The mechanisms may involve exercise-induced reduction in adipose tissue and inflammation, as well as the anti-inflammatory and antioxidant effects of the Mediterranean diet, particularly through omega-3 and omega-6 fatty acids. These findings are clinically significant because they offer a non-pharmacological approach to managing DE, which is often poorly controlled with conventional treatments. However, the study did not track long-term outcomes beyond 6 months, and future research should compare different types of exercise and dietary interventions.