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.
Even minor problems of ozone depletion can have major effects. Every time even a small amount of the ozone layer is lost, more ultraviolet light from the sun can reach the Earth. Every time 1% of the ozone layer is depleted, 2% more UV-B is able to reach the surface of the planet.UV-B increase is one of the most harmful consequences of ozone depletion because it can cause skin cancer. The increased cancer levels caused by exposure to this ultraviolet light could be enormous.he risk of ozone depletion was that too much ultraviolet radiation would reach the earth's surface, resulting in high levels of skin cancer. Industrial processes can result in slightly acidic rain as a result of high levels of sulphur dioxide and nitrogen oxide pollution.