Incidence, mechanism and outcomes of schisis retinal detachments revealed through a prospective population-based study.

Aim: To determine the incidence, presentation and outcomes of progressive sight-threatening retinal detachment (RD) complicating degenerative retinoschisis.
Methods: We conducted the first prospective population-based epidemiological study of progressive schisis detachment over a 1-year period (2014-2015) in the UK. Case ascertainment was via monthly British Ophthalmological Surveillance Unit reporting cards sent to all ophthalmologists in the UK. For each reported case, data were collected using incident and 6 months follow-up questionnaires gathering information including demographic, presenting symptoms, retinal findings, primary management, primary outcome, secondary management and secondary outcome.
Results: Fifty-five cases of progressive schisis RD were identified with similar age distribution to conventional rhegmatogenous RD (mean age 64.0 years, range 20-88), and male-to-female ratio of 2.3:1. The locations of schisis detachments were predominantly supratemporal (46.7%) and infratemporal (35.6%). At least 70% of schisis RD were associated with posterior vitreous detachment (PVD) at presentation and 21% with grade B-C proliferative vitreoretinopathy. Primary management consisted of pars plana vitrectomy (82%), scleral buckle (9%), observation (4%), laser (2%) and combined vitrectomy-buckle (2%). Primary reattachment rate was 70%. Final reattachment rate was 87% with mean best-corrected visual acuity of 0.49 Decimal (SD 0.34) for fovea-on and 0.42 Decimal (SD 0.29) for fovea-off schisis detachments at mean follow-up of 8.7 months (SE 1.0).
Conclusions: The estimated annual incidence of progressive schisis RD was 0.85 per million population (95% CI 0.64 to 1.11), equivalent to around 0.66% of all rhegmatogenous RD. PVD may play a key pathogenic role in the development of progressive schisis detachments. Surgical outcomes are inferior to those of conventional rhegmatogenous RD.
Competing Interests: Competing interests: None declared.
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