Refractive error is an umbrella medical term used to describe conditions that result in poor vision due to the size and/or shape of the eye. There are four different types of refractive errors. They can occur either as a stand-alone condition or co-exist in one patient. Common signs and symptoms include poor vision, heavy tired eyes, tearing, and headaches.
1. Hyperopia (long-sighted): this patient can see things that are along
distance away e.g. driving, TV, etc. but their eyes need to work extra hard to
focus up close.
2. Myopia (short-sighted): this patient can see things up close (short
distance) e.g. reading, a person 1m away, etc. but have problems distinguishing objects as they move further away from them such as the
board in class, road signs.
3. Astigmatism: This occurs when the shape of the eye is more cylindrical (like a rugby ball) than spherical in shape (soccer ball). The eye then has a
problem focusing and these patients tend to have problems with any
prolonged tasks e.g. long-distance driving or reading for a long time.
4. Presbyopia: due to naturally occurring changes that affect the lens found
inside the eye, as people get older they lose the ability to focus up-close e.g.
reading, threading the needle, computer use, etc. This tends to affect people
from the age of 40 onwards give or take a few years.