Predictors of Vitrectomy Outcomes in Myopic Foveoschisis

This prospective pilot study evaluates factors that predict outcomes after vitrectomy for myopic foveoschisis (MFS), a sight-threatening complication of high myopia that can lead to progressive visual loss, foveal detachment, macular holes, and retinal detachment. Although vitrectomy can relieve traction and improve retinal anatomy, the optimal timing of surgery and the factors associated with visual recovery remain uncertain, particularly in patients with relatively good pre-operative vision.

The study will recruit 30 adults aged 40-90 years from Singapore National Eye Centre surgical retina clinics. Participants must have high myopia (worse than -6 dioptres and axial length \>26 mm) with MFS requiring surgery because of progressive vision loss with OCT-confirmed deterioration over six months and/or foveal detachment. Patients with other ocular diseases or conditions that could confound imaging or functional testing, poor surgical candidacy, cognitive impairment, or ungradable imaging will be excluded.

Participants will undergo standard-of-care 23- or 25-gauge pars plana vitrectomy, with fovea-sparing internal limiting membrane peeling or flap, possible gas tamponade, and cataract surgery where clinically indicated. The research does not alter the usual surgical approach; its main purpose is to collect structural and functional outcome data over 12 months.

Assessments will be performed at baseline and during postoperative follow-up, including best-corrected visual acuity, refracted logMAR visual acuity, microperimetry, M-chart testing for metamorphopsia, contrast sensitivity using the Manifold Contrast Vision Meter, and swept-source OCT. OCT measures will include central retinal thickness, foveal detachment, inner and outer macular schisis, lamellar holes, and epiretinal membrane. Demographic and clinical variables, including age, sex, co-morbidities, and lens status, will also be collected.

The primary functional outcome is stable or improved best-corrected visual acuity. Anatomical success is defined as improvement in retinoschisis and resolution of pre-existing foveal detachment. The investigators hypothesise that improvement can occur across a range of MFS severities, and that baseline OCT features and functional measures can help predict 12-month surgical success.

As a pilot study, no formal sample-size calculation is planned. Analyses will describe clinical characteristics, compare outcomes between better and poorer pre-operative visual-acuity groups, and use multivariable logistic regression to identify prognostic factors. Risks are limited to usual surgical complications and confidentiality risks; all study tests are non-invasive. Data will be securely stored, access restricted to the study team, and participants will provide informed consent.

Parallel studies will be conducted with overseas collaborators.