What Is The Power Of Accommodation Of The Eye?

Accommodation in the eye is the process by which the eye increases optical power to maintain a clear image on the retina.  

The focus of the eye is controlled by a number of factors including the iris, cornea, and muscle tissue that alters the shape of the lens so that the eye can focus on both near and far objects.  

Sometimes these muscles don't work properly because the eye is slightly altered in shape, and as people age, the lens becomes harder and cannot be properly focussed leading to poor vision.  

If the point of focus is short of the retina, it's known as "nearsightedness" which means that the eye cannot focus on distant objects.  "Farsightedness" is where people have problems focussing on nearby objects.  

These conditions can usually be corrected using glasses.