Purpose: We followed up 54 patients (95 eyes) with preproliferative diabetic retinopathy (PPDR) for at least 2 years, and then evaluated the proportion developing proliferative diabetic retinopathy (PDR), and the period front diagnosis of PPDR until the development of PDR. Methods: We divided the 95 eyes affected by PPDR into 75 eyes with mild-type and 20 eves with moderate-type based on our previously proposed subclassification, and evaluated long-term (2 or more years) prognosis. Results: The proportion developing PDR was 24% in mild-type and 60% in moderate-type. The average period from diagnosis of PPDR until the development of PDR was 6 years and 5 months in mild-type, 2 years in moderate-type. The cumulative Occurrence rates of PDR at 2, 5, and 10 years were estimated to be 0%. 14%, and 39% in mild-type and 35%, 58%, and 79% in moderate-type, respectively. The proportion developing PDR was significantly, higher and the average period until PDR development significantly shorter in moderate than in mild-type. In mild-type eyes, the rate of progression to moderate-type was 56% and further progression front moderate-type to PDR occurred in 43%. Conclusion: The above results again confirm the Usefulness of our subclassification, and also provide valuable information about the long-term prognosis of PPDR. Jpn J Ophthalmol 2002;46:323-329 (C) 2002 Japanese Ophthalmological Society.
