Purpose: To define diagnostic morphometric parameters for temporal and nasal arcades in fundus central zone, 2nd order vessels and peripheral vessels beyond avascular retina for each type of ROP active stages.Methods: 155 premature children (310 eyes) with I, II, III stages of ROP. The patients were divided according to types of ROP active stages (type 1 — with low risk of ROP progressing, type 2 — with high risk of ROP progressing). Morphometric analysis of digital «RetCam 120» and «RetCam 3» fundus photos was made by means of original soft «ROP-MORPHOMETRY».Results: Renal vessels diameter, and tortuosity index increasing at type 2 (unfavorable) as compared with type 1 (favorable) (p<0.05) was determined at all active ROP stages both in central fundus zone and at periphery. A tendency to retinal vessels diameters decreasing as distance from central zone increasing was shown in the direction of temporal and nasal arcades at all active ROP stages.Conclusion: The given retinal vessels quantitative morphometric parameters might be the precise criteria for high and low risk of ROP progressing determination within each ROP stage
