No / The inner retinal complex is a well-defined layer in spectral-domain OCT scans of the retina. The central edge of this layer at the fovea provides anatomical landmarks that can be observed in serial OCT scans of developing full-thickness macular holes (FTMH). Measurement of the movement of these points may clarify the mechanism of FTMH formation. This is a retrospective study of primary FTMH that had a sequence of two OCT scans showing progression of the hole. Measurements were made of the dimensions of the hole, including measurements using the central edge of the inner retinal complex (CEIRC) as markers. The inner retinal separation (distance between the CEIRC across the centre of the fovea) and the Height-IRS (average height of CEIRC above the retinal pigment epithelium) were measured. Eighteen cases were identified in 17 patients. The average increase in the base diameter (368 microns) and the average increase in minimum linear dimension (187 microns) were much larger than the average increase in the inner retinal separation (73 microns). The average increase in Height-IRS was 103 microns. The tangential separation of the outer retina to produce the macular hole is much larger than the tangential separation of the inner retinal layers. A model based on the histology of the Muller cells at the fovea is proposed to explain the findings of this study.

No / BACKGROUND: A Full Thickness Macular Hole (FTMH) is often associated with vitreomacular traction, and this can be asymmetric with vitreomacular traction on one side of the hole but not the other. In cross-section, the elevated retinal rim around a developed FTMH is seen as a drawbridge elevation, and this drawbridge elevation may be used as a measure of morphological change. Examination of the drawbridge elevation of the retinal rim in FTMH with asymmetric vitreomacular traction may help to clarify the role of vitreomacular traction in the development of FTMH. METHOD: Cases of FTMH were identified with an initial OCT scan showing vitreomacular traction on one side of the hole only and that had a follow-up OCT scan showing progression of the hole. A tangent to the retinal surface at a distance of 700 microns from the axis of the hole was used as a marker of the drawbridge elevation of the retinal rim around the macular hole. Comparisons of the drawbridge elevation and change in drawbridge elevation between the sides with and without initial vitreomacular traction were made. RESULTS: There was no significant difference between the drawbridge elevation, or change in drawbridge elevation, on the side of the hole with initial vitreomacular traction compared to the side without initial traction. CONCLUSION: There is some intrinsic mechanism within the retina to link the morphological changes on the two sides of a FTMH. A bistable hypothesis of FTMH formation and closure is postulated to explain this linkage.

Introduction A full-thickness macular hole (FTMH) is a round deformity in the fovea that involve alllayers of the neurosensory retina. The condition is usually symptomatic and is associatedwith a decreased visual acuity (VA). Large FTMHs are associated to a larger decrease in VA.To treat FTMH pars plana vitrectomy (PPV) is performed to repair the hole. There aredifferent dimensions of instruments in PPV but limited information on the outcome usingeach dimension. Aim This study aims to assess the healing rate of large FTMHs after 25-gauge vitrectomy. Methods The study is a retrospective record review. Patients were identified through the surgicalintervention registry at the Department of Ophthalmology, USÖ. The study included largeFTMHs (diameter > 400 μm) who underwent 25-gauge PPV at USÖ between 2015-2017. Results After 25-gauge PPV 19 (82.6%) out of 23 included eyes healed. No significant difference inhealing rate between subgroups of different sized FTMHs was discovered. Out of 4 eyes thatfailed to heal, 1 patient underwent a reoperation and the other 3 either chose not to or it wasdeemed not indicated. A statistically significant increase in mean VA postoperatively wasobserved. The most reported complications postoperatively were gas cataract and atemporary increase in intraocular pressure. In 7 cases the PPV led to an accelerateddevelopment of cataract and cataract surgery. Conclusion The majority of FTMHs healed after 25-gauge PPV and the mean VA increased after surgery.The most common complications were secondary cataract and temporary increase in IOP.