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Visual Impairment - Causes, Diagnosis and Treatment

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Visual impairment denotes both blindness and loss of vision to a certain extent. The various conditions that cause visual impairment will be discussed in this article.

Written by

Dr. Sumithra. S

Medically reviewed by

Dr. Shikha Gupta

Published At December 22, 2022
Reviewed AtDecember 22, 2022


Eyes are considered the window to our minds. Light enters the eye and passes through the different layers of the eye, like the lens and cornea, and reaches the retina. The retinal layer consists of rods and cones. The information is sent to the brain through the optic nerve; thus, an image is formed for viewing.

Vision is the greatest gift of life. Only with the help of vision can we entirely understand what is happening around us. Unfortunately, many individuals come to a point where their vision gets affected. Vision can get affected in various degrees. Some might lose their vision entirely and are referred to as blindness.

Whereas some people might have blurred vision, some may experience loss of color in the vision. Some may find it difficult to view things nearby, and others may find it difficult to view things at a distance. For some, it may be severe, and for others, it may be mild. It all depends on what kind of medical condition it is causing. Various medical conditions can cause visual impairment, and the causative factor must be diagnosed clearly to treat a visual impairment.

What Are the Various Causes of Visual Impairment?

It is very rare for an individual to become blind or lose vision entirely in later life. However, many cases have been reported as newborns being blind. This is known as congenital blindness. It can be due to an inherited defective gene or the child acquiring infections that may result in blindness. A few conditions can cause visual impairments in later phases of life, and they are as follows.

  • Cataracts - The eyes' lens is generally a clear or transparent layer. The light from the environment will enter the eyes, pass through the lens, and then get directed to the retinal layer, where information is sent to the brain, thus, an image of vision. As a person ages, a cloudy layer will form over the lens layer of the eyes. The lens will become cloudy and thick. Thus, the light rays do not pass through the lens like normal, and the retina will not receive enough light to form a complete picture and thus, resulting in blurred vision. This usually affects people of age 60 to 70. It can be corrected by wearing glasses and lenses. Surgery is the most common treatment modality preferred.

  • Glaucoma - The increased intraocular pressure will damage the optic nerve responsible for taking visual information to the brain to produce an image. If the damage to the optic nerve is severe, the vision gets affected greatly and results in glaucoma. Glaucoma is, in fact, the greatest reason for blindness in people of age above 60. Glaucoma is caused due to blockage of the aqueous humor channel is blocked and as a result of which, the pressure in the eyes increases. Other causes include injury to the eye. Some of the common symptoms include eye pain, redness of the eye, and vision loss.

  • Amblyopia - It is also known as lazy eye. This condition usually occurs because of the inability of one or both eyes to view images. This condition will occur early in life and affects young children and babies. This means that since one eye does not focus on things clearly, the brain will avoid that particular eye, and thus, that eye will become blind. Misaligned eyes are one of the major causes of amblyopia. Crossed eyes are also known as strabismus. Other causes include droopy eyes and refractive errors. The treatment for amblyopia is focused on correcting the weaker eye. The treatment includes wearing an eye patch over the strong eye and working the weaker eye. This needs a lot of training, but it is highly recommended and effective.

  • Diabetic Retinopathy - People who have diabetes are more prone to develop an eye condition called diabetic retinopathy. It is characterized by damage to the arteries of the retinal layer of the eyes and, thus, affects vision greatly. This condition does not show any signs before occurring. Thus, the affected individual will fail to treat the condition at the earlier stages. Smoking, high blood sugar level, and high blood pressure can increase the risk of acquiring diabetic retinopathy. So, it is advised to keep these factors in check and consult an ophthalmologist if suffering from diabetes to rectify the retinopathy at the earlier stages.

  • Trachoma - Trachoma is an inflammatory condition of the eyes caused by a microorganism known as Chlamydia trachomatis. It is a contagious condition and can lead to blindness. This is most prevalent in regions with large populations and poor sanitation.

What Are the Various Tests to Diagnose Visual Impairment?

Some of the common diagnostic measures to diagnose visual impairment include:

  • Visual Acuity Test - Visual acuity will make the patient read the letters and alphabet presented in a chart at a distance. The letters and alphabet will be of different sizes. Based on the reading ability, visual acuity will be measured.

  • Tonometry Test - This test is used to measure intraocular pressure and, thus, helps detect the presence of glaucoma.

  • Visual Field Test - This field test is used to determine the presence of visual field loss, like peripheral vision loss.


The treatment plan will be charted based on the medical condition causing the visual impairment. The treatment options include eyeglasses, surgery, laser surgery, contact lenses, etc. With appropriate treatment, visual impairment can be treated to a greater extent. Earlier consultations with the eye doctor will help prevent the existing condition from becoming complicated.

Dr. Shikha Gupta
Dr. Shikha Gupta

Ophthalmology (Eye Care)


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