Characterization and Classification of Postoperative Cysts After Strabismus Surgery: Clinical, Histological, and Anterior Segment OCT Analysis in a Large German Cohort.

Abstract

In this work, we provide a detailed characterization of a rare complication-subconjunctival cyst formation after strabismus surgery-in a large German cohort. We conducted a retrospective analysis of 822 consecutive patients who underwent strabismus surgery between 2015 and 2022. The patients received comprehensive eye and orthoptic examinations preoperatively, at 1day, and at 3months postoperatively. Cysts were analyzed with slit-lamp examination, anterior segment optical coherence tomography (AS-OCT), and histopathological subsumption. Nineteen cases of postoperative cysts were observed (2.3%), 12 of which underwent surgical revision. Clinical evaluation including slit-lamp and AS-OCT as well as histological analysis resulted in a classification of three types of cysts: type 1, which is a single hyporeflective cyst, type 2, which is a multilobular hyporeflective cyst, and type 3, a dense hyperreflective granulomatous-like cyst. Eta (η) correlation ratio analysis could show a correlation between time of clinical appearance and type of cyst (Eta = 0.63). Most cysts developed within 20days after surgery. Not only did cysts more frequently affect the medial rectus muscle, which in most cases underwent a shortening procedure (11/19 tucks, 4/19 resections) for intermittent exotropia (X(T)), but the cyst also formed earlier than in the lateral rectus muscle (Eta = 0.45). No correlation could be shown between the type of surgical procedure and time of cyst occurrence (Eta = 0.1). Patient age and cyst type correlated strongly (Eta = 0.47). The underlying type of strabismus did not correlate with the type of cyst observed. Our cases showed a strong positive correlation to the type of strabismus (X(T)), age (young patients), and the procedure (tuck/resection). We introduce a grading system for postoperative cysts after strabismus surgery, complementing histopathology and slit-lamp aspects with AS-OCT information.