Establishing an objective quantitative method for assessing the severity of plus disease in retinopathy of prematurity

Abstract

Background: To establish an objective method for assessing plus disease severity in retinopathy of prematurity.

Methods: Six images of plus diseases that were color-coded according to severity and published in the International Classification of Retinopathy of Prematurity, Third Edition (ICROP3) were analyzed. These images were individually processed, and the best-fit curve and vessel course in zone I were obtained using ImageJ software. Tortuosity indices (TIs) of the major vessels in the temporal quadrants were calculated. Data from real-world patients with no plus, pre-plus, and plus diseases were analyzed and compared with those of the ICROP.

Results: The TIs of the arteries and veins, the sum of these TIs, and the artery/vein (A/V) TI ratios increased incrementally from grades 1 to 6. The trend revealed that the arterial tortuosity increased more than the venous tortuosity. The degree of venous tortuosity was similar from grades 3-5 but higher in grade 6. The A/V TI ratio increased in grades 1-3, stabilized in grades 3-5, and peaked in grade 6. Analysis of data from real-world patients showed increased TI of both arteries and veins, similar to the ICROP3. However, the A/V TI ratio did not show an increasing trend.

Conclusion: Objective methods for assessing disease severity can provide insights into the potential pathophysiological mechanisms of plus disease progression. Arterial tortuosity is more prominent than venous tortuosity. Venous features become more prominent as plus disease progresses, which may obscure the progression of arterial tortuosity.

Keywords: ICROP3; Plus disease; Retinopathy of prematurity; Vessel tortuosity.