Keratoconus 

Keratoconus is a non-inflammatory eye condition in which the normally round dome-shaped clear window of the eye (cornea) progressively thins causing a cone-like bulge to develop. This eventually impairs the ability of the eye to focus properly, potentially causing poor vision. 

Early stages of keratoconus are detectable by your local optometrist and typically presents in younger people from teens to early twenties. Vision is often unaffected in the very early stages. It is important to remember that keratoconus does not cause blindness. If left unchecked, further changes in shape, thinning of the cornea and, in advanced stages, scarring cause loss of transparency of the cornea which impairs the ability of the eye to focus properly.  

For more information about Keratoconus the Moorfields Eye Hospital website has lots of useful information, guidance and support. 

Image taken from visionsource-nfe2020.com