Information copyrighted by the American Optometric Association used with permission.
Astigmatism is an eye condition that causes distorted vision due either to the irregular shape of the cornea or the curvature of the lens inside the eye. An irregular shaped cornea or lens prevents light from focusing properly on the retina, the light sensitive surface at the back of the eye. As a result, vision becomes blurred at any distance.
Astigmatism is a common eye condition and most people have some form of astigmatism. Minor amounts of astigmatism generally does not affect a person’s vision and does not require any sort of treatment. Having a larger amount can cause blurred vision, eye discomfort and even headaches.
Astigmatism is often associated with other eye conditions like nearsightedness and farsightedness. Together these vision conditions are referred to as refractive errors because they affect how the eyes bend or “refract” light.
The specific cause of astigmatism is unknown. It can be hereditary and is usually present from birth. It can change as a child grows and may decrease or worsen over time.
Cataracts occur when protein accrues in the lens of your eye making it cloudy. This buildup of protein can inhibit light from passing through the lens, which results in loss of vision. New cells can begin to form on the outside of the lens of your eye compacting the older cells into the center, thus resulting in the cataract.
Causes of cataracts
Most cataracts are due to age-related changes in the lens. However, other factors can contribute to their development including:
- Diabetes mellitus
- Drugs including but not limited to
- Chlorpromazine and other phenothiazine related medications
- Ultraviolet radiation
- Nutritional deficiency
Treatment for cataracts is often determined from much the cataract affects the person’s vision. If the cataract is only affects the person’s vision slightly or not at all, treatment will likely not be needed. Updating eyeglass prescription may provide provisional improvement if is effecting the person’s vision minimally.
When the cataract has progressed to the point where it is affecting a person’s everyday life and functions, surgery is an option for treatment of the cataract. Cataract surgery comprises of removing the lens of the eye and replacing it with an artificial lens. Having an artificial lens requires no extra care and can improve the person’s vision significantly.
Conjunctivitis, or more commonly known as Pink Eye, is an infection of the conjunctiva, which is the thin transparent layer of tissue that lines the internal surface of the eyelid and covers the white part of the eye. It is a common eye disease, particularly in children. It can affect one or both eye. Conjunctivitis can be highly contagious and can be spread very easily. While conjunctivitis is generally minor eye infection, if left untreated it can develop into a more serious problem.
Causes of Conjunctivitis
The cause of conjunctivitis can often vary but below lists the three main categories of conjunctivitis.
- Allergic Conjunctivitis occurs more often amongst people who already suffer from seasonal allergies. At some point they come into contact with a substance that triggers an allergic reaction in their eyes.
- Giant Papillary Conjunctivitis is a type of allergic conjunctivitis caused by the chronic presence of a foreign body in the eye. This condition occurs predominantly with people who wear hard or rigid contact lenses, wear soft contact lenses that are not replaced frequently, have an exposed suture on the surface or the eye, or have a glass eye.
- Bacterial Conjunctivitis is an infection often caused by baccteria from your own skin or respiratory system. Infection can also be transferred from insects, other people, or poor hygiene.
- Viral Conjunctivitis is most commonly caused by contagious viruses associated with the common cold.
- Ophthalmia Neonatorum is a very severe form of bacterial conjunctivitis that occurs in newborn babies and is a very serious condition. If left untreated it can lead to permanent eye damage.
- Chemical Conjunctivitis can be caused by irritations like pollution, high amounts of chlorine in swimming pools, and exposure to harmful chemicals.
Diabetic retinopathy is a condition that occurs in people that have diabetes, which causes continuous damage to the retina, the light sensitive lining at the back of the eye. It is a serious complication of diabetes that will can cause permeate damage to the eye.
Causes of Diabetic Retinopathy
Diabetic retinopathy is the caused from the damage to the tiny blood vessels that sustain the retina. These blood vessels leak blood and other fluids that cause inflammation of retinal tissue and blurring and clouding of vision. This condition can usually affects both eyes. Diabetic retinopathy can cause blindness if left untreated.
Symptoms of Diabetic Retinopathy
Symptoms can vary but often include:
- Seeing spots or floaters in your field of vision
- Blurry or cloudy vision
- Seeing a black or empty spot in the center of your vision
- Troubles seeing at night
Treatment for Diabetic Retinopathy
More often than not, laser treatment, or photocoagulation, is used to discontinue the leakage of blood and fluid into the retina. A laser beam of light can be used to create small burns in areas of the retina with abnormal blood vessels to try to seal the leak.
Dry eye is a disorder in which there are not enough tears to lubricate and nourish the eye. Tears are essential for providing clear vision and for preserving the health of the front of the eye. Those who suffer with dry eyes either do not produce enough tears or have a very low quality of tears. Dry eye is often a chronic problem and is fairly common especially in older people.
Causes of Dry Eye
Insufficient amount of tears — The ability to produce tears tend to diminish with age, medical conditions or also a side effect of particular medications. Other factors that could cause insufficient amount of tears could be environmental such as dry or windy climates.
Poor quality of tears —Tears are made up of three layers: oil, water, and mucus. Each component serves a function in protecting and nourishing the front surface of the eye. A smooth oil layer helps to prevent evaporation of the water layer, while the mucin layer functions in spreading the tears evenly over the surface of the eye.
Treatment for Dry Eyes
Dry eyes can be a chronic condition, but your optometrist can prescribe treatment to keep your eyes healthy, more comfortable, and prevent your vision from being affected. The primary approaches used to manage and treat dry eyes include adding tears, conserving tears, increasing tear production, and treating the inflammation of the eyelids or eye surface that contributes to the dry eyes.
Early stages of keratoconus causes minor blurring and distortion of vision and increased light sensitivity and can start showing in late teens to early 20’s. Keratoconus may progress for 10-20 years and then start to slow in its progression. It can also affect each eye differently.
As keratoconus progresses, the cornea bulges out more causing vision to become more distorted and blurry. The swelling occurs when the strain of the cornea’s protruding shape causes a tiny crack. The swelling may last for weeks or months as the crack heals and is gradually replaced by scar tissue. There are no medicines that can prevent this disorder from progressing but if sudden swelling does occur your doctor can prescribe eye drops for temporary relief.
Eyeglasses or contact lenses can be used to help correct the distorted vision that is caused by the early stages of keratoconus. As the cornea continues to thin while the disorder progresses, rigid gas permeable contact lenses can be used to correct the distorted vision. These contact lenses must be fitted very carefully and generally, recurrent checkups and lens changes might be required to maintain your vision.
Macular degeneration or age-related macular degeneration (AMD) is an eye disorder that usually affects people that are older. It results in a loss of vision in the center of the visual field because of damage to the retina. It is a major cause of blindness and visual impairment in older adults.
Symptoms of Macular Degeneration
Symptoms of Macular Degeneration often include the gradual loss of being able to see object clearly. Objects often appear distorted in shape and straight lines look wavy and crooked. Dark and empty areas appear in the center of vision. Also, the ability to clearly see color is another symptom of AMD.
In its early stages, symptoms of AMD are often overlooked. If any signs of AMD are experience, you should make an appointment immediately. Your optometrist will go through a series of tests to determine the health of your eyes.
Treatment for Macular Degeneration
There are different treatment methods for the two types of AMD.With “dry” macular degeneration, the tissue of the macula progressively becomes thin and stops functioning properly. Although there is not cure for dry AMD and any central vision lost cannot be restored, doctors now believe there is a link between a person’s nutrition and the progression AMD. Changes to the diet to include low-fat food and dark leafy getables have shown to slow vision loss. Vitamins and supplements have also shown to be beneficial
The “wet” macular degeneration can result from flids that leak from blood vessels that have been newly formed under the macula and leads to distorted central vision. Vision loss from “wet” macular degeneration can be very sever and rapid. When caught early it can be treated with a laser treatment. Often referred to as photocoagulation, the laser treatment is a high focused beam of light that seals the blood vessels that have been leaking causing damage to the macula. Photodynamic therapy or PDT uses medicine that is injected into the bloodstream and then activated when laser is shone in the eye. Unfortunately these treatments are not permanent cures and are used to slow progression of vision loss.
Ocular hypertension is when there is an increased pressure in your eyes that is above pressure range that is considered normal with no detectable changes in vision or damage to the structure of your eyes. It can affect people of any age, but it occurs more frequently in African Americans, people over the age of 40, and people with histories of glaucoma or ocular hypertension in their family.
Ocular hypertension does not have any noticeable signs or symptoms. You can have tests that can check your eye with a tool called a tonometer and can examine the structures of your eyes to examine the health of your eye.
There is an increased risk that those with ocular hypertension can develop glaucoma, but not all people with ocular hypertension will develop glaucoma. There is no cure for it, but with treatment and monitoring can decrease risk of damage.
Presbyopia is a condition of the eye where the crystalline lens in your eye loses flexibility which results in difficulty focusing on close objects. It may seem that it occurs very suddenly, however, the loss of flexibility actually takes place over a number of years. It generally becomes noticeable in people in their early to mid 40’s. Presbyopia cannot be prevented and is not a disease, but it is a natural aging process of the eye.
Signs of Presbyopia
Signs and symptoms of presbyopia can include having to hold books or reading materials at an arm’s length, distorted vision when at a normal reading distance, and headaches along with eye fatigue.
Living with Presbyopia
If you are dealing with presbyopia, your doctor may prescribe reading glasses, bi or trifocals, or contact lenses to help deal with the distorted vision. Periodic changes in your eyewear may be necessary to maintain clear and comfortable vision because the effects of presbyopia continue to change the ability of the crystalline lens to focus properly.