From owner-i_see@indiana.edu Wed Mar 22 00:48:59 EST 1995 From: Grant Sayer Subject: Re: Total Ignoramus Here! (Re: Reply to this message!) Date: Wed, 22 Mar 1995 15:42:41 +1000 (EST) Status: RO X-Status: Hi, Just a few corrections. > > >Here's my question: > > > >My soft extended-wear contact lenses start wearing out about 9 months > > extended wear lenses are not very good for the eyes, and you should > have frequent check ups. common problems include veins growing > accross the retina, due to oxygen deprivation. build ups, infections etc. Veins don't grow as a result of lens wear. The only place that ther is any change is in the cornea, and typically there is an inducement to capillary formation (neovascularisation) from induced hypoxia. Other major complications include; - increased threshold corneal thickness - changes in the corneal endothelium - greater risk of corneal ulcer(s) > > as far as vision is concerned, contacts dont correct astigamism > very well, cause they tend to rotate around on some people. so > you may find glasses give clearer vision. its not really know > just what this poor correction of astigmatism does. soft contact lenses may not fully correct the astigmatism if there is rotation. RGP lenses do a better job provided that the astigmatism is corneal and not lenticular. > > If you want to improve you should give yourself as many "lens-free" > days as you can manage. You may even be better off getting normal > daily lenses and wearing them only while at work and using glasses > for things like driving. If the script is very high then contact lenses give better image formation owing to the back vertex power of the lens being closer to the nodal point of the eye. > > >My eyes don't really get irritated, except in summer when I am subjected > >to blasts of dry air-conditioned air and my eyes get stuck in the open > >position with the lenses cemented firmly to them, or in conditions where > >even normal-sighted people would have problems. air conditioning affects contact lenses due to the low humidity of air conditioners causing higher surface evaporation on the lens. =========================================================================