Influencing factors of low vision 2 years after vitrectomy for proliferative diabetic retinopathy: an observational study

BACKGROUND: Proliferative diabetic retinopathy (PDR) can seriously affect the vision and quality of life of patients. The present study aimed to evaluate the clinical effect of vitrectomy for PDR by observing visual recovery and postoperative complications and to explore the factors influencing low vision. METHODS: This was a case series observational study. Consecutive eyes of patients with PDR who underwent 23G vitrectomy in our hospital within one year (2019.11-2020.11) were collected and followed up for more than 2 years. Patients’ visual acuity, surgical complications and management were collected before the operation and during the follow-up. Decimal visual acuity was recorded and converted to the logarithm of the minimal angle of resolution (logMAR) for statistical analysis. Excel was used to establish a database, and SPSS 22.0 statistical software was used for data analysis. RESULTS: A total of 127 patients and 174 eyes were included in the study. The mean age was 57.8 years. The best corrected visual acuity (BCVA) was < 0.3 in 89.7% of eyes before surgery and ≥ 0.3 in 48.3% of eyes after surgery. Among 174 eyes, visual acuity improved in 83.3%. There was no change in 8.6% of eyes, while 8.1% of eyes had decreased visual acuity after surgery. The average logMAR visual acuity was 1.5 ± 0.7 before surgery and 0.7 ± 0.6 after surgery, indicating significant improvement (p < 0.05). Logistic regression analysis showed that intraoperative silicone oil filling and postoperative complication were significant risk factors for postoperative low vision, while preoperative pseudophakic lens and postoperative intra vitreal injection of anti-VEGF were protective factors for vision recovery (p < 0.05). The incidence of postoperative complications was 15.5%, top three of which were vitreous haemorrhage, neovascular glaucoma and traction retinal detachment. CONCLUSION: Vitrectomy is safe and effective in the treatment of PDR with few complication. Postoperative intra vitreal injection of anti-VEGF is a protective factor for vision recovery. TRIAL REGISTRATION: The trial registration number is ChiCRT2100051628, and the date of registration was September 28, 2021.