I. Present state of diabetic retinopathy treatment
Recent estimates suggest that Japan has approximately 10 million patients with diabetes, 3 million with diabetic retinopathy, 700 thousand with proliferative diabetic retinopathy, and 650 thousand with diabetic macular edema. Diabetic retinopathy is the third most prevalent cause of visual impairment in Japan, accounting for 12.8%. Diabetic retinopathy causes decreased visual acuity in the prime working population, thereby posing a huge societal burden. Therefore, strategies to maintain visual acuity are required to extend people's healthy life expectancy.
II. Onset, progression risk, and molecular pathogenesis of diabetic retinopathy and macular edema
Systemic conditions related to diabetes, such as hyperglycemia, induce the impairment of retinal capillary endothelial cells, and ensuing retinal circulatory dysfunction and ischemia damage the retinal tissue. The molecular pathogenesis of this process involves polyol metabolic pathway acceleration, late advanced glycation end products, protein kinase C activation due to enhanced endogenous diacylglycerol production, reactive oxygen species, vascular endothelial growth factors (VEGF) related to inflammation, cytokines such as interleukin 6, and other physiologically active substances.
III. Treatment strategy
In addition to controlling systemic factors, such as hyperglycemia and hypertension, a viable treatment strategy needs to be established targeting the molecular pathogenesis of retinopathy. Compared with surgery prior to advanced visual impairment, vitreous surgery for the deterioration of vision caused by proliferative retinopathy improves the prognosis of visual acuity. To treat diabetic macular edema, intraocular localized administrations of anti-inflammatory agents targeting the molecular pathogenesis of inflammation and steroids need to be combined with other therapeutic modalities.
IV. Future challenges
Each patient should receive effective tailor-made medical treatment based on appropriate medical evidence.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 123: 203-225, 2019.