Refractive error is the result of light rays entering the eye that are not focused on the retina, causing blurred vision. An irregular shape of the eye or cornea, or loss of elasticity of the lens surface due to aging may decrease the focusing power of the eye. Eyeglasses, contact lenses, or refractive surgery can correct vision compromised by refractive error.
N e a r s i g h t e d (Myopia)
Objects close to you are clear while far away vision is blurry. This usually occurs prior to age 20. It should be monitored closely since rapid changes can occur. There is a tendency to inherit nearsightedness. It is not a cause of loss of vision or blindness. In later years, it may improve.
F a r s i g h t e d (Hyperopia)
Vision at near can be strained resulting in eye fatigue, avoidance of near tasks, or blurry vision. As hyperopia worsens, the blur can progress to intermediate and far distances. The farsighted person’s eyes might only be in focus at great distance: often one mile!
A s t i g m a t i s m
Astigmatism is usually the result of an irregular shaped cornea or lens. The cornea is shaped like an egg or football. Vision may be blurred at all distances. The severity varies and most people have some amount of astigmatism. It may occur with hyperopia or myopia.
P r e s b y o p i a
A reduction of focusing ability for anything closer than an arm’s length causing blurring, fatigue and eyestrain. This usually begins in the late 30’s and worsens with age, requiring stronger and stronger prescriptions to maintain optimal vision.
P r i s m
A lens correction for tiny imbalances between the alignment of the two eyes.