Eyesight problems are often the result of what is called a refractive error. A refractive error reduces your quality of vision and is a common reason that patients are recommended to wear spectacles.
There are four main types of refractive error:
This is the term used to describe short-sightedness in a patient. A myopic patient’s eye is too long for its optical system, preventing rays of light from reaching the retina and causing difficulty with distance vision.
Contrary to myopia, hypermetropic patients enjoy good distance vision, but struggle to see clearly at closer range. Hypermetropia can result when the eye is too short for the optical system, when the cornea is not sufficiently curved, or when the lens is not thick enough.
This is the term used to describe an eye that is of irregular shape. An astigmatic eye is not perfectly spherical, and will be shaped more like a rugby ball. Astigmatism is very common, and causes blurred vision as rays of light are not focused correctly.
This is an age-related reduction in the eye’s ability to focus on objects at close distances. This is caused by a loss of elasticity of the lens over time, and will ultimately require correction such as intermediate/reading glasses.