Study on the Recovery of Visual Perceptual Function Dysfunction in Patients With Diabetes

Inclusion Criteria: * moderate to severe non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy(PDR) prior to treatment(17) * prior pan retinal laser photocoagulation (PRP) at least 4 weeks before enrollment or vitreoretinal surgery at least 8 weeks before enrollment * stable clinical condition * best-corrected visual acuity (BCVA) \> 1.0 logMAR (equivalent to a Snellen visual acuity of \< 20/200) * clear refractive media * age ≤ 65 years * ability to comprehend the examination and training procedures Exclusion Criteria: * significant refractive media opacity * psychiatric disorders, chronic alcoholism and traumatic brain injury * new-onset vitreous hemorrhage, myopia, strabismus, amblyopia, glaucoma and macular diseases.