A Study On The Effects Of Radiotherapy On Retina And Choroid In Patients With Head Tumor By UWF-SS-OCTA

Head radiation therapy can cause irreversible damage to retinal blood vessels,leading to visual impairment.Currently,there is no effective treatment for radiation-induced retinopathy,making early diagnosis particularly important.This study aimed to explore changes in retinal blood flow density,peripapillary retinal nerve fiber layer(p RNFL)blood flow density and thickness,foveal avascular zone(FAZ)area and perimeter,choroidal thickness,choroidal vascular index(CVI)and visual evoked potential(VEP)in patients with radiation-induced retinopathy in order to identify early indicators of radiation-induced retinopathy.Methods:Forty-one patients with a history of head tumor radiation therapy,with a total of 80 eyes,were enrolled in the study.Thirty-seven normal subjects,with a total of73 eyes,matched for age,gender,and axial length,were selected as controls.All participants underwent best-corrected visual acuity(BCVA),refraction,intraocular pressure measurement,axial length measurement,anterior segment and ultra-widefifield color fundus photography,and ultra-widefield swept-source optical coherence tomography angiography(UWF-SS-OCTA)examinations.VEP was also performed in some radiation-treated patients.The data from the two groups were compared.Results : Compared with the normal controls,radiation-treated patients showed significantly decreased superficial and deep retinal blood flow density(P<0.01),slightly increased FAZ area,significantly increased FAZ perimeter(P=0.004),and there was no significant difference in choroid thickness,while CVI decreased significantly.p RNFL blood flow and thickness increased on the temporal side,decreased on the nasal and inferior sides.VEP revealed normal P100 wave latency but reduced amplitude.Conclusions:Radiation therapy can cause damage to the retina and optic nerve,which can be detected in the early stages using UWF-SS-OCTA.The main manifestations include a decrease in superficial retinal blood flow density and a decrease in the p RNFL blood flow density in the nasal side,but an increase in the temporal side.Damage to the choroid is characterized by a decrease in CVI.