Silicone Oil Tamponade for Vitrectomy of Hypermyopic Foveoschisis.

Inclusion Criteria: * patients with spherical ≥ -8 diopters or axial length ≥ 26.5mm. * The foveoshisis combined with foveal detachment was showed on the OCT image. The foveal detachment height≥ 250 um ,and the thickness of sensory retina of foveal detachment was ≤100 um; * patients signed the ICF. * patients with BCVA ≤0.5,and with visual disturbance symptoms. Exclusion Criteria: * patients with macular hole * accompanied or secondary of other fundus disease * received vitrectomy due to other diseases * glaucoma cannot be controled by medication * patients with other retinal or choroidal disease that may affect VA * poor patients compliance * poor condition that cannot undertake the surgery * optical opacities which make it difficult to exam fundus or measure on OCT