Optical assessment of ocular blood flow in laser-treated diabetic retinopathy: An ocular pulse amplitude analysis

Non-invasive optical assessment of ocular blood flow has gained increasing importance in evaluating vascular complications of diabetic retinopathy (DR). Ocular pulse amplitude (OPA), an optical parameter derived from continuous intraocular pressure recording, reflects pulsatile choroidal blood flow and may serve as an accessible hemodynamic biomarker in DR. This study aimed to evaluate OPA as an optical indicator of ocular hemodynamic changes in laser-treated and untreated diabetic retinopathy.

In this cross-sectional study, OPA was measured using an optical tonometric device (Dynamic Contour Tonometer, Pascal, Ziemer Ophthalmic Systems) in 150 eyes from 150 subjects: 50 with proliferative DR who had undergone panretinal photocoagulation (PDRP), 50 with non-proliferative DR without prior laser treatment (NPDRP), and 50 healthy controls. Systemic parameters, medication use, and ocular biometric data were recorded. Multivariable linear regression identified independent predictors of OPA.

Mean OPA was significantly lower in PRP-treated PDRP eyes (2.6 ± 1.4 mmHg) than in NPDRP (3.3 ± 1.1 mmHg; mean difference -0.7 mmHg, 95% CI -1.2 to -0.2, p = 0.006) and controls (3.1 ± 1.0 mmHg; -0.5 mmHg, 95% CI -1.0 to -0.04, p = 0.040). PDRP stage (β=-0.44, p = 0.002), systolic blood pressure (β=0.33, p < 0.001), and female sex (β=0.19, p = 0.028) independently predicted OPA (adjusted R²=0.37).

Optical assessment of OPA reveals significant hemodynamic alterations in PRP-treated proliferative DR eyes. The observed OPA reduction likely reflects the combined hemodynamic impact of advanced diabetic vascular pathology and PRP-induced choroidal changes. OPA may serve as a non-invasive optical parameter for monitoring ocular hemodynamic status in patients undergoing long-term PRP treatment.