Watched annually on the second Thursday of October, World Sight Day is an occasion intended to draw consideration on visual deficiency and vision disability. It was initially started by the Sight First Crusade of Lions Club Global Establishment in 2000.
World Sight Day and Cataract Blindness
Age related cataract remains the major cause of visual impairment throughout the world. It is estimated that the present number of 20 millions of cataract blind will double by the year 2020.
The primary reason for the low uptake of cataract surgery medical procedure in developing nations is poor examination and high expense.
This World Sight Day, we bring before you the list of six most widespread eye diseases in the world, that can only be fought with the tool of awareness.
6 Types of Eye Diseases
1. Age-Related Macular Degeneration (AMD)
Age-related macular degeneration, or AMD is a physical disturbance that affects the centre of the retina also known as the macula. The macula is the part of the eye responsible for our most acute vision, which we use when reading, driving, and performing other activities that require fine, sharp, or straight-ahead vision.
There are two different types of AMD:
- Dry macular degeneration: Small yellow deposits which are commonly known as drusen, deposits under the macula. Eventually, these deposits destroy the vision cells, causing them to break down. The functioning of macula reduces which causes a gradual loss of central vision as time goes on. It is the most common form of AMD which affects approximately 90% of people who have the disease.
- Wet macular degeneration: New blood vessels increases in areas of the macula where they shouldn’t be. This causes rapid damage to the macula that can lead to the loss of central vision in a short period of time. Although this type of AMD affects only about 10% of people with the disease, it is responsible for 90% of severe vision loss associated with AMD.
Symptoms of AMD
In the early stages, AMD is ignored and can only be detected through an eye exam, which may reveal drusen agglomeration. However, as AMD grows, drusen impair the ability of vision cells to transport vital nutrients to the macula, which leads to noticeable symptoms :
Treatments for AMD
Since peripheral vision is not affected, many people with dry AMD continue in their normal lifestyles with the aid of low-vision optical devices, such as magnifiers.
Wet AMD is treated with injected medications or by a laser surgery by sealing off the leaking blood vessels. These are usually brief and painless outpatient procedures that slow and sometimes even reverse the progression of the degeneration.
There are currently no treatments for dry AMD, although the use of some nutritional supplements have been shown to slow the progression.
2. Cytomegalovirus (CMV)
Cytomegalovirus is an infection that attacks the light-sensing cells in the retina. As it is a serious disease that should be diagnosed and treated immediately, because it can lead to loss of vision, and in the worst situation , blindness.
Cytomegalovirus is a common source of infection in humans and generally lays dormant in the body without producing symptoms. While most people’s immune systems are able to stave it off, those with weakened immune systems are vulnerable to its effects. It is particularly prevalent in people with AIDS (Acquired Immune Deficiency Syndrome) – although continued progress in anti-retroviral therapies have reduced the prevalence of late-stage AIDS.
Symptoms of CMV
Many people with CMV retinitis experience no symptoms. However, there are certain signs that may be indicative of the virus which can be floaters or flashes in the eye, blind spots or blurred vision and loss of peripheral vision.
Treatments for CMV
A person with a weakened immune system experiencing any signs should see a retina specialist as soon as possible.
There are several medications that aim to minimize the effects of CMV retinitis. The sooner you begin treatment, the better chance that vision can be helped. Also, if only one eye is infected, receiving proper systemic treatment early may protect the other eye.
Oral, injected and intravenous medication are all used to slow the progression of the disease, and need to be taken on a weekly basis.
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3.Strabismus (Crossed Eyes)
Strabismus occurs when a person’s eyes are not able to align on the same point at the same time and appear to be misaligned or pointed in different directions.
Usually, this results from the weakness of the muscles in one or both eyes. The weak eye will turn in toward the nose and away from the object that it is supposed to be focused on. The eye that turns off-target may be the same in every incidence or it could be a different eye at different times.
Crossed eyes develop most often in babies. It is easier to correct when caught early. This is often not a condition babies or children simply outgrow so children with eyes that seem to be misaligned should be examined and treated if necessary.
Signs of Crossed Eyes
The most obvious sign of crossed eyes is when the eyes appear to be pointed in different directions. There are, however, more signs of crossed eyes that can most often be observed in children, including:
- Eyes that do not move together
- Unsymmetrical points of reflection in each eye
- Tilting the head to one side
- Inability to gauge the depth
- Squinting with only one eye
Treatments for Crossed Eyes
In order to improve vision, the weakened muscles in the affected eye or eyes must be put to work. Several treatments may be used alone or in combination, depending on the type, severity, and cause of strabismus, including:
- Spectacles or contact lenses – This method may help people who have crossed eyes due to an uncorrected longsightedness.
- Injected medication – Also known as Botox, the injection relaxes the contracted muscles in the eyes, making it easier for eyes to focus where they need to.
- Surgery – This method has a high success rate although it is expensive and involves more risk than other options.
- Patching or covering the better-seeing eye – Similar to eye drops or ointment as this method works to strengthen the weakened eye.
Glaucoma is a condition that causes damage to the eye's optic nerve and gets worse over time. It's often linked to a buildup of pressure inside your eye. Glaucoma tends to be inherited and may not show up until later in life.
The increased pressure known as the intraocular pressure can damage the optic nerve which transmits images to your brain. If the damage continues, glaucoma can lead to permanent blindness within a few years if not treated.
Most people with glaucoma have no early symptoms or pain.
There are four different types of glaucoma, stemming from different causes:
Chronic open-angle glaucoma: The most common form of the disease, chronic open-angle glaucoma results from a pressure build-up in the eye and causes severe vision loss without the warning of noticeable symptoms.
Acute closed-angle glaucoma: This arrives suddenly and painfully. It is extremely serious and can cause permanent vision loss quickly.
Secondary Glaucoma: It gets its name because it arrives as a result of something else, including previous medical conditions, injuries, irregularities, or medications.
Normal-tension glaucoma: It is a form of glaucoma where the tension in the eye is inexplicably normal, yet the optic nerve is still damaged. This is rare, considering glaucoma is usually characterized by a high amount of intraocular pressure.
Symptoms of Glaucoma
Glaucoma often develops with no symptoms, making it impossible for patients to detect until irreversible damage has been done. For this reason, it is critically important to frequently be checked by an eye doctor for an irregularly high amount of intraocular pressure that can signal a person is at high risk for glaucoma.
In the case of acute closed-angle glaucoma, symptoms will be sudden and severe, including:
Treatments for Glaucoma
Prescription eye drops can decrease eye pressure by slowing the production of fluids within the eye or improving the drainage flow. This may not be right for every patient because of the varying side effects.
Glaucoma surgery improves the flow of fluids from the eye by relieving pressure on the optic nerve. Your doctor may use a highly focused laser beam to modify the existing drainage route or to create an alternate hole in the iris, depending on the type of glaucoma you have.
Keratoconus is a condition that results from an irregularly shaped cornea, which prevents light from focusing correctly on the retina. In keratoconus, the normally round cornea becomes thin and cone-shaped, causing blurred vision and sensitivity to bright lights.
Symptoms of Keratoconus
In the early stages, keratoconus causes slightly blurred vision and increased sensitivity to bright lights. As it progresses (over 10 to 20 years), vision may become more distorted.
An eye care professional can determine the presence of keratoconus using a slit lamp evaluation or by examining the surface of the cornea through corneal topography. Symptoms of keratoconus include:
- Distorted vision at all distances
- “Ghost” images – the appearance of several images when looking at one object
- Noticeably worse vision in one eye
Treatment for Keratoconus
In the early stages, keratoconus is essentially a mild astigmatism. As such, it can be treated in similar ways:
- Contact lenses or spectacles are an effective treatment for most cases of keratoconus, this method adjusts focus to correct visual distortion.
- Gas permeable (GP) lenses: The patients whose condition has progressed, GP lenses will correct for the misshapen cornea by masking it with the smooth outer surface of the contact lens.
6. Retinal Detachment
Retinal detachment occurs when the retina becomes separated from the nerve tissues and blood supply underneath it. While painless, visually this has a clouding effect that has been likened to a grey curtain moving across the field of vision.
Retinal detachment is a treatable condition, but it must be taken care of promptly, or it can cause vision loss and in the worst cases, blindness.
Symptoms of Retinal Detachment
An eye care professional can determine retinal detachment through a number of retinal and pupil response tests, ranging from simple visual acuity testing to an ultrasound of the eye.
For the patient, the grey curtain mentioned above occurs after retinal detachment has already begun. Before this happens, there are signs and symptoms that can alert one to the possible onset of retinal detachment, including:
- Eye floaters accompanied by eye flashes
- Sudden onset of blurred vision
- Shadows or blind spots in the field of vision
Treatment for Retinal Detachment
Surgery has proven a highly successful treatment for retinal detachment, provided the condition has been detected early enough. To ensure that treatment can be effective, anyone experiencing the symptoms above should be given medical attention within 24 hours. Typical surgical procedures include:
- Laser surgery: Repairs tears in the retina that are the underlying cause of separation
- Pneumatic retinopexy: A tiny gas bubble is placed in the eye that floats the retina back into place it usually is accompanied by laser surgery to ensure the retina stays in the correct position permanently.
- Scleral buckle: Suturing a silicone buckle to the eye that indents the wall of the eye into a position that allows the retina to reattach.
Sharma YR, Sudan R. Concise textbook of Ophthalmology. Elsevier; New Delhi: 2007. Community Ophthalmology; pp. 206–210.
Vision 2020 India Newsletter September 2007. Article on Internet.
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Shrestha JK, Pradhan YM, Snellingen T. Outcomes of extracapsular surgery in eye camps of eastern Nepal. Br J Ophthalmol 2001;85:635–7, and 648–52.
- Foster A. Cataract and “Vision 2020—the right to sight” initiative. Br J Ophthalmol 2001;85:635–7.
Tags: Rare Eye Diseases, Eye Diseases That Cause Blindness, Common Eye Infections, Sudden Vision Changes
Elina is a general health writer for Cheap Medicine Shop and holds a diploma in health and fitness studies. She hails from Canada and is specialized in writing about a plethora of diseases, diets and more. Apart from being an ardent writer, Elina is also a dedicated reader and no literary discussion at the workplace is complete without her insightful participation.