Impact of physical activity on visual outcomes among persons with type 2 diabetes: A scoping review of randomized controlled trials.

PURPOSE: The global burden of Type 2 diabetes mellitus (T2DM) is increasing, with diabetic eye complications remaining a leading cause of irreversible blindness. Current evidence suggests that physical activity may help mitigate diabetes-related microvascular complications. This scoping review synthesized evidence from randomized controlled trials (RCTs) assessing the impact of physical activity interventions on visual outcomes in individuals living with T2DM.

METHODS

Using the JBI framework, a search of MEDLINE, CENTRAL, SCOPUS, JSTOR, and clinical trial registries was conducted yielding 3634 records, of which 8 RCTs satisfied the inclusion criteria. The included studies were conducted across 8 countries with varied designs, intervention protocols, outcome measures, and study durations.

RESULTS

The findings revealed mixed outcomes regarding how physical activity affects visual outcomes. Of the 8 included RCTs, 4 reported beneficial effects (including significant decreases in central macular thickness, reduced risk of retinal microaneurysm formation, and lower diabetic retinopathy incidence or progression), 3 reported no significant effect, and 1 reported an unanticipated increase in retinopathy incidence in intervention groups. This review highlights critical gaps, including the lack of standardised visual outcome measurements, insufficient exploration of contrast sensitivity, colour vision, and visual fields, and limited or no follow-ups. Additionally, adherence to physical activity interventions may have been influenced by social determinants of health, such as socioeconomic status, cultural factors, and healthcare accessibility.

CONCLUSION

This review highlights the need for further high-quality RCTs with standardised physical activity protocols and comprehensive visual assessments. The findings offer a basis for incorporating structured physical activity into diabetes care, especially in resource-limited settings.

REGISTRATION: The scoping review is registered with Open Science Framework (https://doi.org/10.17605/OSF.IO/856YB).