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.
1 Depletion of the ozone layer was identified by the US Academy of Sciences in 1976 as being in agreement with the available data. 2  The ozone hole was discovered by Joseph Farman (team leader), Brian Gardiner, and Jonathan Shanklin in 1984 (reported in 1985).