Evaporative Dry Eye
There is excessive evaporation of tears. Causes of evaporation are: 1- Meibomian Gland DysfunctionWhich is the most common cause of dry eye.There will be deficiency of lipid or oil layer of the tear which acts as a protective against evaporation.2- Exposure of Ocular SurfaceDefects in eyelids which can be either due to mechanical or neurological can cause chronic dry eye which can sometimes severe.Mechanical causes can occur either after eyelid trauma, after surgical procedures or there is abnormality in the position of the globe like proptosis. Neurological causes lead to poor blinking reflex which is normally about 15 blinking per minutes. It can occur in stokes and Bells palsy or facial nerve palsy. Both of these causes can cause abnormal blinking, incomplete closure of the eyelids and abnormal lid-globe congruity with either entropion (in-turning of the lids toward the globe) or ectropion (out-turning of the lids from the globe) leading to more exposure of ocular surface to atmosphere and more evaporation of tear films.
3- Environmental FactorsSuch as sun, hot climate with lower humidity, wind and dry air that commonly occurs in the cabins of airplanes and smoking. Also jobs that require visual concentration like working on computer for a long time, driving, reading, watching TV for along period and towards the end of the day. These factors will increase tear evaporation by decreasing the blinking rate.4- Contact Lenses and Dry EyeWearing them for a long time can increase the evaporation rate of tear and it will decrease the rate flow of tears.<<< Previous, Deficiency of Tear Production Do You Have A comment or A question to ask about Evaporative Dry Eyes?Please share it with us! Leave Evaporative Dry Eye and go to Dry Eyes Main Page
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