Refractive Errors and Vision

Eyesight is the most precious gift we have. It allows us to perceive the surrounding world like no other of our senses. Unfortunately, there are quite a lot of eye disorders that can permanently affect the quality of vision. Early recognition and treatment are the keys to preserving eyesight. Here are some of the most common eye disorders with some handy tips how to detect them and what measures to take.

Myopia (Nearsightedness)

Nearsightedness is one of the most common eye disorders typical for both children and adults. A recent study of the National Eye Institute found that nearly every third person in the USA suffers from myopia and showed 66% increase of its prevalence for the last 30 years. Myopia is characterized by the inability of a person to clearly see distant objects and is cause by the eye having too much power or being longer than normal. During the initial stages of the condition there might be only a little blurring of far away objects. As it progresses, the clear visual range shortens.

Myopia can be treated with glasses, contact lenses or refractive eye surgery.

Hyperopia (Farsightedness)

Hyperopia is an eye disorder characterized by eyestrain and blur with close vision. If a person has a high degree of farsightedness it will also affect their distance vision. Early complaints of hyperopic patients are eyestrain, headaches, blurred vision and occasionally eye crossing, especially in children.

Magnifying lenses are needed to add power to the eye, which clears the vision of a farsighted person. This can be done with glasses, contact lenses, or refractive surgery in some cases.

Astigmatism

Astigmatism is characterized by an irregular curvature of the cornea, or in some cases, the crystalline lens. Astigmatism occurs in most people to some degree. A person’s eye is naturally spherical with even curvature. When light enters an eye without astigmatism, it refracts evenly, creating a clear view of the object. The eye of a person with astigmatism is shaped more like a football or the back of a spoon. For this person, when light enters the eye it is refracted more in one direction than the other, allowing only part of the object to be in focus at one time. Objects at any distance can appear blurry and wavy.

Glasses, toric contact lenses, and refractive surgery are all options to correct astigmatism.

Presbyopia

Presbyopia is an age related problem that prohibits a person from focusing on near objects. Presbyopia’s exact mechanisms are not known but research most strongly supports a loss of elasticity of the crystalline lens, although loss of power of the cilliary muscles that bend the lens for focusing could also be a cause. Symptoms of presbyopia usually start after the age of 40. Unlike farsightedness, presbyopia does not blur distance vision.

Treatments are reading glasses for those with good distance vision, bifocal or progressive lenses, and mono vision or multifocal contact lenses. Refractive surgery is usually not an option to correct presbyopia.