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Diagnosis/Diseases/Treatment
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Amblyopia is a term used to describe an uncorrectable loss of vision in an eye that appears to be normal. It's commonly referred to as "lazy eye" and can occur for a variety of reasons. A child's visual system is fully developed between approximately the ages of 9-11. Until then, children readily adapt to visual problems by suppressing or blocking out the image. If caught early, the problem can often be corrected and the vision preserved. However, after about age 11, it is difficult if not impossible to train the brain to use the eye normally. Some causes of amblyopia include: strabismus (crossed or turned eye), congenital cataracts, cloudy cornea, droopy eyelid, unequal vision and uncorrected nearsightedness, farsightedness or astigmatism. Amblyopia may occur in various degrees depending on the severity of the underlying problem. Some patients just experience a partial loss; others are only able to recognize motion.Patients with amblyopia lack binocular vision, or stereopsis - the ability to blend the images of both eyes together. Stereopsis is what allows us to appreciate depth. Without it, the ability to judge distance is impaired.
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Signs and Symptoms:
Poor vision in one or both eyes
Squinting or closing one eye while reading or watching television
Crossed or turned eye
Turning or tilting the head when looking at an object
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Note: Children rarely complain of poor vision. They are able to adapt very easily to most visual impairments.
Parents must be very observant of young children and should have a routine eye exam performed by the age of 2-3 to detect potential problems. Detection and Diagnosis
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When amblyopia is suspected, the doctor will evaluate the following: vision, eye alignment, eye movements, and fusion (the brain's ability to blend two images into a single image).
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Treatment:
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The treatment for amblyopia depends on the underlying problem. In some cases, the strong eye is temporarily patched so the child is forced to use the weaker eye. For children with problems relating to a refractive error, glasses may be necessary to correct vision. Problems that impair vision such as cataracts or droopy eyelids often require surgery. Regardless of the treatment required, it is of utmost importance that intervention is implemented as early as possible before the child's brain learns to permanently suppress or ignore the eye.
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There are many types of cataracts. Most are caused by a change in the chemical composition of the lens. These changes may be caused by aging, heredity or birth defects, injury to the eye, or certain diseases or conditions of the eye or body. The normal process of aging can cause cataracts. Cataracts may develop in children as well as in adults of any age. When they appear in children they may be hereditary or may have been caused by infection. These are called congenital cataracts and are present at birth. Eye injuries can cause cataracts in people of any age. A hard blow, puncture, cut, intense heat or chemical burn can damage the lens, resulting in a traumatic cataract. Certain infections or diseases, result in secondary cataracts. Depending on the size and location of the cloudy areas in the lens, a person may or may not be aware that a cataract is developing. If the cataract is located on the outer edge of the lens, no change in vision may be noticed, but if it is located near the centre of the lens, it usually interferes with clear sight. As cataracts develop, there may be hazy, fuzzy and blurred vision.Double vision may also occur. The eyes may be more sensitive to light and glare. There may be a need to change the eyeglass prescription frequently. As the cataract worsens, stronger glasses no longer will improve sight. It may help to hold objects closer to the eye to read and do close-up work. The pupil, which is normally black, may undergo noticeable changes in colour and appear to be yellowish to white.
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Normal eye
Image Source: http://www.eyeguys.net/dis01cataracts.html |
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Detection and Diagnosis and Treatment:
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Cataracts cannot usually be seen from the outside of the eye without proper instruments. When a cataract interferes with work or lifestyle, it is probably time to have it removed. Cataract surgery is highly successful and over 90% of patients who undergo surgery regain useful vision. It is important to understand that complications may occur and, as with any surgery, a good result cannot be guaranteed. Once the cloudy lens of the eye is removed, the patient needs a substitute lens to focus light. These may include glasses, contact lenses or intraocular lenses (IOLs, permanent lenses surgically implanted inside the eye in place of the natural lens).
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Eye with cataract
Image Source: http://www.eyeguys.net/dis01cataracts.html |
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Color blindness may be a hereditary condition or caused by disease of the optic nerve or retina. Patients with a color vision defect caused by disease usually have trouble discriminating blues and yellows. Inherited color blindness is most common; affecting both eyes, and does not worsen over time. This type is found in about 8% of males and 0.4% of females. Color blindness may be partial (affecting only some colors), or complete (affecting all colors). Complete color blindness is very rare. Those who are completely color blind often have other serious eye problems as well. Photoreceptors called cones allow us to appreciate color. These are concentrated in the very center of the retina and contain three photosensitive pigments: red, green and blue. Those with defective color vision have a deficiency or absence in one or more of these pigments. Those with normal color vision are referred to as trichromats. People with a deficiency in one of the pigments are called anomalous trichromats (the most common type of color vision problem.) A dichromat has a complete absence in one cone pigment.
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Signs and Symptoms:
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The symptoms of color blindness are dependent on several factors, such as whether the problem is congenital, acquired, partial, or complete.
Difficulty distinguishing reds and greens (most common)
Difficulty distinguishing blues and greens (less common)
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Serious color blindness:
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Objects appear as various shades of grey (this occurs with complete color blindness and is very rare
Reduced vision
Nystagmus
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Detection and Diagnosis:
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Color vision deficiency is most commonly detected with special coloured charts called the Ishihara Test Plates. On each plate is a number composed of coloured dots. While holding the chart under good lighting, the patient is asked to identify the number. Once the color defect is identified, more detailed color vision tests may be performed. Treatment There is no treatment or cure for color blindness. Those with mild color deficiencies learn to associate colors with certain objects and are usually able to identify color as everyone else. However, they are unable to appreciate color in the same way as those with normal color vision.
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Conjunctivitis, commonly known as pink eye, is an infection of the conjunctiva (the outer-most layer of the eye that covers the sclera). The three most common types of conjunctivitis are: viral, allergic, and bacterial. Each requires different treatments. With the exception of the allergic type, conjunctivitis is typically contagious. The viral type is often associated with an upper respiratory tract infection, cold, or sore throat. The allergic type occurs more frequently among those with allergic conditions. When related to allergies, the symptoms are often seasonal. Allergic conjunctivitis may also be caused by intolerance to substances such as cosmetics, perfume, or drugs. Bacterial conjunctivitis is often caused by bacteria. The severity of the infection depends on the type of bacteria involved.
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Conjunctivitis
Image Source: http://www.stlukeseye.com/Conditions/Conjunctivitis.asp
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Signs and Symptoms:
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Viral conjunctivitis
Watery discharge
Irritation
Red eye
Infection usually begins with one eye, but may spread easily to the fellow eye
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Diagnosis:
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Conjunctivitis is diagnosed during a routine eye exam using a slit lamp microscope. In some cases, cultures are taken to determine the type of bacteria causing the infection.
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Treatment:
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Conjunctivitis requires medical attention. The appropriate treatment depends on the cause of the problem. For the allergic type, cool compresses and artificial tears sometimes relieve discomfort in mild cases. In more severe cases, non-steroidal anti-inflammatory medications and antihistamines may be prescribed. Bacterial conjunctivitis is usually treated with antibiotic eye drops or ointments that cover a broad range of bacteria. Like the common cold, there is no cure for viral conjunctivitis; however, the symptoms can be relieved with cool compresses and artificial tears (found in most pharmacies). For the worst cases, topical steroid drops may be prescribed to reduce the discomfort from inflammation. Viral conjunctivitis usually resolves within 3 weeks.
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You may sometimes see small specks or clouds moving in your field of vision. They are called floaters. Floaters are actually tiny clumps of gel or cells inside the vitreous. Floaters may also look like specks, strands, webs or other shapes. Actually, what you are seeing are the shadows of floaters cast on the retina, the light-sensitive part of the eye. You see floaters because they are inside your eye; they move with your eyes when you try to see them. You may also see flashes of light. These flashes occur more often in older people as the vitreous humor thickens and tugs on the light-sensitive retina. They may be a warning sign of a detached retina. Flashes also occur after a blow to the head, often called "seeing stars." Eye floaters and spots are usually harmless, but flashes of light may indicate a problem. If you're suddenly seeing spots, floaters or flashes, get an eye exam to make sure nothing's wrong. Some people experience flashes of light that appear as jagged lines or "heat waves" in both eyes, often lasting 10-20 minutes. These types of flashes are usually caused by a spasm of blood vessels in the brain, which is called a migraine. What Causes Eye Floaters and Spots?
For most people, floaters occur as they grow older. The vitreous humor thickens and clumps as we age, and floaters result from the clumped vitreous gel. Eye injury or breakdown of the vitreous humor may also cause spots and floaters. When people reach middle age, the vitreous gel may start to thicken or shrink, forming clumps or strands inside the eye. The vitreous gel pulls away from the back wall of the eye, causing a posterior vitreous detachment. It is a common cause of floaters, and it is more common for people who:
Are nearsighted
Have undergone cataract operations
Have had inflammation inside the eye
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Eye floaters and spots are usually harmless, but flashes of light may indicate a problem. If you're suddenly seeing spots, floaters or flashes, get an eye exam to make sure nothing's wrong.
Image Source: http://www.allaboutvision.com/conditions/spotsfloats.htm
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Treatment:
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Most spots and eye floaters are merely annoying but harmless when they temporarily enter the field of vision, and many fade over time. People sometimes do surgery to remove floaters, but rarely.If you suddenly see new floaters, or eye floaters accompanied by flashes of light or peripheral vision loss, it could indicate other serious conditions. the retina can tear if the shrinking vitreous gel pulls away from the wall of the eye. This sometimes causes a small amount of bleeding in the eye that may appear as new floaters.
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This eye disease is characterized by abnormally high fluid pressure inside the eyeball, damaged optic disk, hardening of the eyeball, and partial to complete loss of vision. Your eye has pressure just like your blood, and when this intraocular pressure (IOP) increases to dangerous levels, it damages the optic nerve. This can result in decreased peripheral vision and, eventually, blindness. The eye constantly produces aqueous, the clear fluid that fills the anterior chamber (the space between the cornea and iris). The aqueous filters out of the anterior chamber through a complex drainage system. The delicate balance between the production and drainage of aqueous determines the eye's intraocular pressure (IOP).
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Common types of glaucoma:
Open Angle
Open angle (also called chronic open angle or primary open angle) is the most common type of glaucoma. With this type, even though the anterior structures of the eye appear normal, aqueous fluid builds within the anterior chamber, causing the IOP to become elevated. Eye drops are generally prescribed to lower the eye pressure. In some cases, surgery is performed if the IOP cannot be adequately controlled with medical therapy. Patients with open angle glaucoma don't typically have symptoms. Acute Angle Closure
Only about 10% of the population with glaucoma has this type. Acute angle closure occurs because of an abnormality of the structures in the front of the eye. In most of these cases, the space between the iris and cornea is more narrow than normal, leaving a smaller channel for the aqueous to pass through. Those with angle closure glaucoma may experience severe eye pain accompanied by nausea, blurred vision, rainbows around lights, and a red eye. This problem is an emergency and should be treated by an ophthalmologist immediately. If left untreated, severe and permanent loss of vision will occur in a matter of days.
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Symptoms:
Sudden decrease of vision
Extreme eye pain
Headache
Nausea and vomiting
Glare and light sensitivity
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Secondary Glaucoma:
This type occurs as a result of another disease or problem within the eye such as: inflammation, trauma, previous surgery, diabetes, tumor, and certain medications. For this type, both the glaucoma and the underlying problem must be treated.
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This is a rare type of glaucoma that is generally seen in infants. In most cases, surgery is required.
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Symptoms:
Light sensitivity
Enlargement of the cornea
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Detection and Diagnosis and prevention:
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The glaucoma evaluation has several components. In addition to measuring the intraocular pressure, doctors will also evaluate the health of the optic nerve (ophthalmoscopy), test the peripheral vision (visual field test), and examine the structures in the front of the eye with a special lens (gonioscopy) before making a diagnosis. The progression of glaucoma is monitored with a visual field test. This test maps the peripheral vision, allowing the doctor to determine the extent of vision loss from glaucoma and a measure of the effectiveness of the treatment. The structures in the front of the eye are normally difficult to see without the help of a special gonioscopy lens. This special mirrored contact lens allows the doctor to examine the anterior chamber and the eye's drainage system. Most patients with glaucoma require only medication to control the eye pressure. Surgery is indicated when medical treatment fails to lower the pressure.There are several types of procedures, some involve laser and can be done in the office, others must be performed in the operating room. The purpose of any glaucoma operation is to allow fluid to drain from the eye more efficiently.
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Stats:
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Glaucoma affects an estimated 3 million Americans, with 120,000 blind due to the condition. Elsewhere in the world, glaucoma treatment is less available, and glaucoma ranks as a leading cause of blindness just about everywhere. Even if people with glaucoma do not become blind, vision can be severely impaired.
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Age-related macular degeneration (ARMD) is a degenerative condition of the condition macula This cause of vision loss in the United States in those are mostly 50 or older, thus showing its prevalence as it is noticed with increasing with age. Caused by hardening of the arteries that nourish the retina. This deprives the sensitive retinal tissue of oxygen and nutrients that it needs to function and thrive. As a result, the central vision deteriorates. Macula is an opaque spot on the cornea (the central retina).
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Dry macular degeneration
results in a gradual loss of vision
Image Source: http://www.stlukeseye.com/Conditions/MacularDegeneration.asp
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Signs and Symptoms:
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Distorted vision (Straight lines such as a doorway or the edge of a window may appear wavy or bent.
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What is the difference between wet and dry macular degeneration?
AMD is classified as either wet (neovascular) or dry (non-neovascular). About 10% of patients who suffer from macular degeneration have wet AMD. This type occurs when new vessels form to improve the blood supply to oxygen-deprived retinal tissue. However, the new vessels are very delicate and break easily, causing bleeding and damage to surrounding tissue. Dry is when no help is given to situation and the situation evolves and worsens by itself.
What causes macular degeneration?
Macular degeneration may be caused by variety of factors. Genetics, age, nutrition, smoking, and sunlight exposure may all play a role.
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Developement of new blood vessels under the retina causes hemorrhage, swelling, and scar tissue
Image Source: http://www.stlukeseye.com/Conditions/MacularDegeneration.asp
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Detection and Diagnosis:
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Eye physicians usually diagnose AMD. Vision testing, Amsler grid test, ophthalmoscopy, fundus photography and fluorescein angiography are some common tests performed during a retinal exam.
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Treatment:
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There is no proven medical therapy for dry macular degeneration. In selected cases of wet macular degeneration, laser photocoagulation is effective for sealing leaking or bleeding vessels. Unfortunately, laser photocoagulation usually does not restore lost vision, but it may prevent further loss. Recently, photodynamic therapy has proven to be effective in stopping abnormal blood vessel growth in some patients with wet AMD. This new type of laser treatment is far less damaging than laser photocoagulation and is the treatment of choice in many cases. Early diagnosis is critical for successful treatment of wet macular degeneration. Patients can help the doctor detect early changes by monitoring vision at home with an Amsler grid.
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The dry type is much more common and is characterized by drusen and loss of pigment in the retina
Image Source: http://www.stlukeseye.com/Conditions/MacularDegeneration.asp
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Macular hole is a problem that affects the very central portion of the retina. It happens for a variety of reasons such as: eye injuries, certain diseases, and inflammation inside the eye. However, the most common cause is related to the normal aging process. The vitreous gel inside the eye is firmly attached to the macula. With age, the vitreous becomes thinner and separates from the retina. Sometimes this creates traction on the macula, causing a hole to form. Macular holes often begin gradually and affect central vision depending on the severity and extent of the problem. Partial holes only affect part of the macular layers, causing wavy, distorted, blurred vision. Patients with full-thickness macular holes experience a complete loss of central vision. Signs and Symptoms
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The severity of the symptoms is dependent on whether the hole is partial or full-thickness.
Blurred central vision
Distorted, "wavy" vision
Difficulty reading or performing tasks that require seeing detail
Gray area in central vision
Central blind spot
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Detection and Diagnosis:
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Visual acuity testing, Amsler grid, and ophthalmoscopy are all performed to evaluate the macula's health and function. The retina doctor may also order photographs of the macula prior to performing surgery to repair the hole.
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Treatmentb:
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Some macular holes seal spontaneously and require no treatment. In many cases, surgery is necessary to close the hole and restore useful vision. Macular holes are repaired with surgery. During the operation, the surgeon first gently removes the vitreous gel with a procedure called vitrectomy. This eliminates any traction on the macula. A gas bubble is injected in the eye to place gentle pressure on the macula and help the hole to seal. In many cases, patients enjoy functional vision after the bubble has dissipated and the eye has healed.
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