ObjectiveTo observe the clinical evolution process and imaging characteristics of choroidal lesions in different subtypes of serpiginous choroiditis (SC), and to explore the clinical significance of subtype classification. MethodsA retrospective, uncontrolled and observational study. A total of 45 eyes of 25 SC patients diagnosed in Yunnan Eye Hospital from May 2009 to September 2021 were included in the study. According to the initial location of the lesion and fundus images, including fundus color photography, fundus fluorescein angiography (FFA), optical coherence tomography (OCT) and other examination results. SC was divided into peripapillary serpiginous choroiditis, macular serpiginous choroiditis and ampiginous choroiditis. According to the shape of the lesions at the first diagnosis, it can be divided into new lesions with only infiltrating edema, old lesions with only atrophy and recurrent lesions with coexistence of edema and atrophy. the imaging features, development and complications of different subtypes of ocular lesion were observed. ResultsAmong the 45 eyes of 25 cases, 15 cases were male and 10 cases were female, 20 cases of binocular and 5 cases of monocular, age was 42.3±5.7 years old. There were 21 eyes with active lesions, of which 5 eyes were new lesions and 16 eyes with recurrent lesions; 24 eyes were old lesions. Concurrent optic disc edema occurred in 3 eyes; mild vitreitis occurred in 5 eyes; retinal occurred vasculitis in 3 eyes; choroidal neovascularization occurred in 3 eyes. Among the 16 cases (64%, 16/25) of the peripapillary serpiginous choroiditis, 2 cases (2 eyes) were monocular, and 14 cases (28 eyes) were binocular. Active lesions were found in 16 eyes, of which patients with binocular lesions only one had active lesions. The choroidal lesions that were close to the optic disc or around the optic disc, expanded outwards centrifugally with the prolongation of the disease course, and can progress to the macula. The edge of the lesion was tortuous, with a geographic-like, amoeboid-like and finger-like, polypoid or propeller-like shape. Active lesions in FFA showed weak fluorescence in the early stage and strong fluorescence in the late stage; the old lesions showed weak fluorescence in the early stage and mottled fluorescence in the late stage, and mostly strong fluorescence on the edge. OCT showed thickening of active lesions and thinning of old lesions. Among the 4 cases (16.0%, 4/25) of macular type, 2 cases (2 monocular eyes) had active lesions; 2 cases (4 eyes) had lesion in both eyes, among them, 1 case (2 eyes) had old lesion, and the other case had alternate active lesions. The initial lesions were all located in the off-center of the macula, and most of them were disk-shaped and progressing centrifugally to the periphery. The FFA and OCT imaging findings of the lesions were similar to those of the peridisc type. Among the 5 cases (20.0%, 5/25) of ampiginous choroiditis, 1 case (1 eye) was monocular and 4 cases (8 eyes) were binocular. These lesions were multiple old lesions of varying sizes, gray-white with pigmentation, with clear borders in the posterior pole. Among them 4 eyes have new active lesions appeared near the old lesions. The old lesions showed weak fluorescence with clear borders, and the fluorescein leakage at the late edge formed a strong fluorescence ring; the active lesions showed weak fluorescent spots with blurred edges, and the fluorescence was slightly enhanced in the late stage. In old lesions, atrophy of the photoreceptor layer, RPE and choroid can be seen, and RPE hyperplasia in some areas. ConclusionsSC subtype is a classification of the location of the first lesion, but the characteristics of the repeated attack of this disease can lead to the annihilation of each subtype due to the continuous expansion of the lesion. The phenomenon that the fundus active lesions only occur in one eye that can explain the clinical manifestations of asymmetric morphology of binocular lesions. The characteristics of binocular subtype warn that the predilection site of the healthy eye should be paid attention to.