Abstract:AIM: To analyze the changes of retinal structure and function before and after panretinal photocoagulation(PRP)in patients with proliferative diabetic retinopathy(PDR).
METHODS: Prospective study. Totally 98 cases(98 eyes)of PDR patients who underwent PRP in Eye Hospital of Wenzhou Medical University from January 2022 to May 2023 were included. Optical coherence tomography angiography(OCTA)was used to detect central retinal thickness(CRT), central macular thickness(CMT), subfoveal choroidal thickness(SFCT), foveal avascular zone(FAZ), deep vascular complex(DVC)blood flow density, superficial vascular complex(SVC)blood flow density before and at 1 wk, 1 and 3 mo after PRP. During the follow-up, 1 eye underwent vitrectomy, 2 eyes were lost to follow-up, and finally 95 eyes completed 1 a follow-up, with a loss rate of 3%. According to the visual prognosis at 1 a after treatment, the patients were divided into two groups: 73 eyes in good prognosis group and 22 eyes in poor prognosis group(including 9 eyes of visual disability and 13 eyes of visual regression). The changes in retinal structure and function before and after PRP treatment were compared between the two groups of patients, and the receiver operating characteristic(ROC)curve and decision curve were used to analyze the predictive value of retinal structure and function for PDR treatment.
RESULTS: There were statistical significant differences in PDR staging, CRT, CMT, SFCT, DVC blood flow density, and SVC blood flow density between the two groups of patients before treatment(all P<0.05). At 1 wk, 1 and 3 mo after treatment, the FAZ area of both groups decreased compared to before treatment, while the blood flow density of DVC and SVC increased compared to before treatment(both P<0.05). However, there was no significant difference in the blood flow density of FAZ, DVC, and SVC between the two groups at 1 wk, 1 and 3 mo after treatment(all P>0.05). The CRT, CMT and SFCT of the two groups at 1 wk after treatment were higher than those before treatment(all P<0.05), but there were no significant differences between the two groups(all P>0.05). The CRT, CMT and SFCT at 1 and 3 mo after treatment were lower than those at 1 wk after treatment and before treatment in both groups. The CRT, CMT and SFCT in the poor prognosis group at 3 mo after treatment were higher than those at 1 mo after treatment, and were higher than those in the good prognosis group(all P<0.05). ROC analysis showed that, at 3 mo after laser treatment in PDR patients, the area under the curve of the CRT, CMT, and SFCT alone or in combination after treatment for 1 a was 0.788, 0.781, 0.783, and 0.902, respectively, and the combined prediction value was better(P<0.05). Decision curve analysis showed that the combined detection of CRT, CMT, and SFCT in PDR patients at 3 mo after treatment can improve the predictive value of visual prognosis.
CONCLUSION: The optimal time for retinal structure and function recovery in PDR patients after PRP treatment is between 1 wk and 1 mo. OCTA measurement of CRT, CMT, and SFCT at 3 mo after treatment can predict the visual prognosis during the 1 a treatment period.
