Study On The Ultra-widefield Autofluorescent Characteristics Of Retinitis Pigmentosa

Objective: To summarize retinal pigment epithelium atrophy patterns in retinitis pigmentosa(RP)by analyzing the feature of ultra-widefield fundus autofluorescent imaging(UWFAFI).Methods: Retrospective case series.Patients clinically diagnosed as RP and had UWFAFI and ultra-widefield fundus imaging(UWFI)in Guangzhou Aier Eye Hospital from January 2017 to December 2021 were enrolled.According to the features of pigment distribution and FAF,the peripheral FAF and macular FAF were classified,and their correlations with age,best-corrected visual acuity(BCVA)and foveal thickness were analyzed.Result: 208 eyes of 105 patients were included.According to the DAF patterns in the middle and periphery of UWFAFI,the patients were divided into three types: paving stone(n = 27),speckle(n = 63),and type of composite(paving stone + speckle,n = 15).The correlation between the feature of autofluorescence and fundus pigmentation was investigated.It was found that all crystalline retinal degeneration cases present with paving stone hypoautofluorescence in UWFAFI.The patients with white dot retinitis pigmentosa and no pigmentation showed speckled or mixed-type peripheral retinal.Further,patients with paving stone FAF were older than the other two types.Since crystalline retinal degeneration has distinct macular FAF changes,they were not included in the macular FAF characteristic studies.According to the features of macular FAF,we classified them into three types,including concentric circle(34 cases),paving stone(6 cases),and irregular shape(57 cases),which were well correlated with age,BCVA,and central retinal thickness.According to the difference in autoflourescence pattern of the fovea,types were defined as hyperautofluorescence ring(42 cases),fovea hyperautofluorescence(7cases),spotted hypoautofluorescence(42 cases)and type of nummular hypoautofluorescence(6 cases).The extent of macular isoautofluorescence was graded according to their progression form,grade 1(39 cases),grade2(13 cases),grade 3(36 cases),and grade 4(9 cases).The fovea isoautoflourescence typing and grading correlated well with BCVA and central retinal thickness rather than age.Besides,we also revealed that the patients with RP had symmetrical fundus lesions.The patients in the same family shared similar FAF patterns and pigmentation forms.In the patients with mutations in the same gene at different loci,their FAF patterns were different.Conclusion: The results suggest that the pattern of FAF changed with age and correlated well with visual acuity and macular retinal structure.The feature of UWFAF in peripheral and macular is a vital imaging marker for evaluating the diagnosis of RP and monitoring disease progression.The features of FAF are somehow related to the genotype and reflect the degeneration pattern of retinal photoreceptor cells and RPE.UWFAFI is a valuable tool for studying the phenotype in RP.In addition,UWFAFI helps the differential diagnosis in children and adolescents cases.