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.
Where is ozone found in the atmosphere? Ozone is mainly found in two regions of the Earth's atmosphere. Most ozone (about 90%) resides in a layer that begins between 6 and 10 miles (10 and 17 kilometers) above the Earth's surface and extends up to about 30 miles (50 kilometers).This region of the atmosphere is called the stratosphere.The ozone in this region is commonly known as the ozone layer. The remaining ozone is in the lower region of the atmosphere, which is commonly called the troposphere. The figure (above) shows an example of how ozone is distributed in the atmosphere.ost ozone (about 90%) resides in a layer that begins between 6 and 10 miles (10 and 17 kilometers) above the Earth's surface and extends up to about 30 miles (50 kilometers).