Disorder of Refraction or Refractive Disorder: Symptoms, Types, Treatment, Epidemiology, Causes

“Your eyes speak the truth when everything else is a lie.” You must have heard of this quote. However at times during certain conditions, the eyes do not speak the absolute truth for it does not give you the clear picture about what you see. Now you must be wondering about what exactly we are going to present here. Well! This article will focus on one of the disorders of the eyes which can be categorized under the visual problems caused due to a loss of the refractive power of the eyes or the conditions in eyes caused due to disorder of refraction or the refractive disorders. Here we will discuss on the causes, types, symptoms, diagnosis and treatment procedures available for disorder of refraction.

In order to focus the light rays coming to the eyes at the retina, the lens and the cornea of the eye bends them towards the retina and we are able to see various objects. However in case of a disorder of refraction or refractive disorder there is a loss of focus or the refractive power. More about this will be discussed in the following paragraphs of the article.

Any error in eye that causes a loss of the refractive power or the power to focus the light rays on the retina leading to various visual problems is called as the disorder of refraction or refractive disorder. There are various reasons behind this loss of refractive power including the loss or lowering of the elastic quality of the lens capsule with aging and increasing time, defects in the curvature of the cornea, due to excessively small or excessively long eyeballs which make it difficult to focus sharply etc.

It can be said that the refractive error or the disorder of refraction are usually common which results in a blurred vision or also at times may lead to visual impairment. Disorder of refraction or refractive disorder can be corrected by various means including the use of contact lens, eye glasses and refractive surgery. More on the treatments and management of the disorder of refraction will be explained in the later section of the article.

When we look at the epidemiology of the disorder of refraction or the refractive disorder; the worldwide prevalence of such a disorder has been estimated from somewhere between the range of 800 million to 2.3 billion. As per the WHO, there are 153 million people globally live with visual impairment because of uncorrected disorder of refraction or the uncorrected refractive errors.

Though the children as well as the adults can be affected by the refractive errors or the disorders of eyes, however Presbyopia especially affects most of the adults above the age of 35 years. It is also that children of the affected parents are more likely to develop with the disorder of refraction in their lifetime.

Most common signs and symptoms include the following:

• Double and Blurred Vision (which is in fact the most common symptom in disorder of refraction or refractive disorder)
• Haziness is one another symptom of disorder of refraction or refractive disorder
• Eye squinting or frowning may be experienced sometimes
• Headaches may be experienced in people with disorder of refraction
• Glare around bright lights
• Eye strain
• Dry out eyes, itching, redness and irritation in eyes can also be experienced.

The various types of refractive errors or the disorders of refraction or refractive disorders can be explained under specific categories based on their underlying causes and symptoms. Here below are some of the most common types of disorder of refraction along with their explained causes.

1. Myopia (Nearsightedness): Myopia is also called as Nearsightedness and is a condition in eye which occurs when the eyeball is excessively long for the refractive power of the cornea and the lens and thus it becomes difficult for them to focus the light rays on the retina. Due to the long eyeball the light rays gets focused in front of the retina instead of being focused on it. This makes is difficult for the affected person to see distant object clearly. In case of the children, the nearsightedness increases until they stop growing further.
2. Hyperopia (farsightedness): Hyperopia is also called as farsightedness and is a condition of the eye where the person affected is unable to see the nearby objects. This occurs when the eyeball is excessively small for the refractive power of the cornea and the eye lens. Thus, instead of the light rays being focused on the retina, they get focused behind the retina. Though young children with mild hyperopia can be able to see the nearby objects in case their lens are flexible enough to refocus the light on the retina; it becomes difficult for the adults for see the nearer objects in hyperopia as the eye lens stiffen up with aging. Blurred vision is common here in this case.
3. Astigmatism: In this condition there is an imperfect shape of the eye lens or the cornea in the affected person. Thus there may be a blurred vision in the person at any distance. This can be corrected by using cylindrical lenses
4. Presbyopia: This is a type of disorder of refraction or refractive disorder of eye which occurs with aging as the flexibility of the eye lens declines. This makes it difficult for the eye lens to change its shape. Thus during such a condition of the eye the affected person finds it difficult to see the nearby objects. This usually affects the people above 40 years of age. It can be treated by using eye glass, progressive lenses etc.
5. Aphakia: This is another disorder of refraction or refractive disorder of the eye which is marked by an absence of the eye lens. It may be a birth defect or may occur due to an eye injury or eye surgery for a cataract removal. There is a blurred vision in the patient while seeing the distant objects.
6. Anisometropia: In this type of disorder of refraction or refractive disorder there is a significant difference seen between the refractive errors of both the eyes.

There are certain risk factors involved in the occurrence of disorder of refraction of any of the above mentioned types. Let us take a look below on some of the most common causes leading to the refractive errors or the disorders of refraction in eyes.

• Genetics can be considered as one of the important factor causing disorders of refraction. Though myopia is known to b present in many connective tissue disorders, chromosomal or the X-linked disorders etc, there are also specific genes which have been identified to be causing myopia and its symptoms in refractive errors of the eye.
• Environmental factors are also included under the leading cause for the disorder of refraction, especially the myopia. Reading more can cause myopia in children. In fact it has also been reported that children spending most of the time reading are more likely to be affected with myopia than the children who spent playing outdoors. Thus there is certainly a correlation between the environmental factors and the risk for developing the refractive errors.

A saying from M.K Gandhi comes as, “A correct diagnosis is three-fourth the remedy.” So here we must be taking a look on some of the most popular diagnosis methods available to know about the condition of disorder of refraction or the refractive disorder in human being. Before we proceed further on this we must tell you that it is essential for every individual to have a regular eye test or eye examination done by an ophthalmologist in every one or two years. By doing this, an early diagnosis of any disorder of refraction can be made possible for better and effective treatments to begin for correcting the error of refraction.

During the eye examination, there is a use of a Snellen eye chart which is used to determine the visual acuity or the sharpness of vision in a person. This visual acuity is measured in relation to what a normal or unimpaired eye sees. Taking an example to explain this, a person with 20/60 vision is able to see at 20 feet of distance what a person with normal vision is able to see at 60 feet distance. Testing of eye generally also includes certain tests of the visual fields, eye pressure and the movements of eyes.

There are some of the effective treatment procedures available which can help in treating the disorder of refraction or refractive disorder. Some of them are listed below.

1. Eyeglasses: This is in fact the most common and the safest and simplest ways to correct the errors in refraction of the eye or refractive disorder. By undergoing an eye test or eye examination under a professional eye care provider, you will be able to get your appropriate eye lens for your eyeglasses to be worn on eyes so as to have an optimal vision in you.
2. Contact Lenses: Apart from the eyeglasses, the contact lens are also considered as safe and an effective option for correcting the disorder of refraction or refractive disorder in case they fit properly and are used in an appropriate manner. Here, the contact lens act by becoming the first refractive surface for the light rays incoming into the eye and causing a more precise focus or refraction. In many cases contact lens provide clearer vision, and a greater comfort to the affected people in refractive errors of the eye. It is extremely important for you to wash your hands properly and clean your lenses in an appropriate way so as to keep away from any risk of infection. It must also be informed that certain condition in disorders of refraction do not allow you to wear the contact lenses. So you must have a thorough and proper discussion with your eye specialist before going for any such treatment
3. Refractive Surgery: Though most of the eye condition in disorder of refraction can be treated by eyeglasses and contact lenses, there are certain conditions which might require surgical treatment or the laser procedures. Nearsightedness, farsightedness and astigmatism are some of the common conditions in eye which can be treated by refractive surgery. Actually, the refractive surgery is used so as to reshape the cornea or the lens for making it better able to focus the incoming light rays on the retina. It must be noted that a thorough discussion with an expert ophthalmologist is highly essential for you before going for such a treatment procedure of refractive surgery. There are certain limitations which must be taken in to account like the patients with eye disease, an autoimmune or a connective tissue disease etc must not go for a refractive surgery. This treatment procedure benefits the healthy individuals above 18 years of age with healthy eyes. It can be truly said that refractive surgery for treating disorder of refraction in eye are undergone for convenience and better cosmetic purposes; yet not c for all the people with refractive errors in the eye.

“Your eyes are the most beautiful part of your body, for they make you see this beautiful world!” It is highly essential for every individual to take care of his/her eyes and keep a check on its proper vision. Make sure you are having your general eye examination in every one or two years and keeping self aware of any disorder of refraction in eye at its earlier phase. As they say, “An early diagnosis is half way to a perfect treatment”. Also keep noted to have a thorough discussion with your eye specialist before opting for any of the treatment procedures so as to keep away from any unwanted risk or side effects.

“Keep safe your eyes, they are your wonders!”

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