Data on vitrectomy. 1  Patients with proliferative retinopathy have a 33% risk of a vitreous haemorrhage at some time. 2  About 25% of these haemorrhages are recurrent or severe and need a vitrectomy. 3  After vitrectomy about 20% bleed needing a washout.  After vitrectomy, 33% have vision better than 6/18. 3% develop rubeotic glaucoma.
The Earth's atomospheric ozone layer is located in the tropopause, which is located just. above the troposphere. The tropopause is the bottom limit of the stratosphere several. miles above the surface of the Earth.
STRATOSPHERIC OZONE DEPLETION Ozone depletion is a global problem that is caused by human activities. This newmodule in the Global Change Instruction Program describes the chemistry of ozone,how ozone destruction is attributed to human activity, and what society is doing toavert further damage to the ozone layer.TRATOSPHERIC OZONE DEPLETION Ozone depletion is a global problem that is caused by human activities. This newmodule in the Global Change Instruction Program describes the chemistry of ozone,how ozone destruction is attributed to human activity, and what society is doing toavert further damage to the ozone layer.