Problems and Diseases
Amblyopia, also known as lazy eye, is a vision development disorder in which an eye fails to achieve normal visual acuity, even with prescription eyeglasses or contact lenses.
Amblyopia begins during infancy and early childhood. In most cases, only one eye is affected. But in some cases, reduced visual acuity can occur in both eyes.
Particularly if lazy eye is detected early in life and promptly treated, reduced vision can be avoided. But if left untreated, lazy eye can cause severe visual disability in the affected eye, including legal blindness.
It’s estimated that about 2 to 3 percent of the U.S. population has some degree of amblyopia.
Astigmatism is probably the most misunderstood vision problem. For starters, it’s called “astigmatism,” not “stigmatism.” (You don’t have “a stigmatism” — you have astigmatism.)
Like nearsightedness and farsightedness, astigmatism is a refractive error, meaning it is not an eye disease or eye health problem; it’s simply a problem with how the eye focuses light.
In an eye with astigmatism, light fails to come to a single focus on the retina to produce clear vision. Instead, multiple focus points occur, either in front of the retina or behind it (or both).
Blepharitis is a common eyelid inflammation that sometimes is associated with a bacterial eye infection, symptoms of dry eyes or certain types of skin conditions such as acne rosacea.
Blepharitis has two basic forms:
- Anterior blepharitis, affecting the outside front of the eyelid where eyelashes are attached.
- Posterior blepharitis, linked to dysfunction of meibomian glands within the eyelids that secrete oils to help lubricate the eye.
It’s common to have a mixture of both anterior and posterior forms of blepharitis at the same time, but in different degrees of severity.
Although eye doctors commonly diagnose blepharitis, it can be difficult to find permanent relief of the symptoms that can include burning, flaking, crusting, tearing, irritation, itching, redness in eyelid margins and a foreign body sensation.
A cataract is a clouding of the eye’s natural lens, which lies behind the iris and the pupil.
Cataracts are the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world. In fact, there are more cases of cataracts worldwide than there are of glaucoma,macular degeneration and diabetic retinopathy combined, according to Prevent Blindness America (PBA).
Today, cataracts affect more than 22 million Americans age 40 and older. And as the U.S. population ages, more than 30 million Americans are expected to have cataracts by the year 2020, PBA says.
Types of cataracts include:
- A subcapsular cataract occurs at the back of the lens. People with diabetes or those taking high doses of steroid medications have a greater risk of developing a subcapsular cataract.
- A nuclear cataract forms deep in the central zone (nucleus) of the lens. Nuclear cataracts usually are associated with aging.
- A cortical cataract is characterized by white, wedge-like opacities that start in the periphery of the lens and work their way to the center in a spoke-like fashion. This type of cataract occurs in the lens cortex, which is the part of the lens that surrounds the central nucleus.
Cytomegalovirus (CMV) retinitis is a sight-threatening disease frequently associated with Acquired Immunodeficiency Syndrome (AIDS). In the past, about a quarter of active AIDS patients developed CMV retinitis.
However, this figure is dropping dramatically, thanks to a potent combination of drugs used to treat AIDS that help restore function of the immune system. In recent years, these drugs have helped decrease presence of CMV retinitis in late-stage AIDS by more than 80 percent.*
A cornea transplant replaces diseased or scarred corneal tissue with healthy tissue from an organ donor.
There are two main types of cornea transplants: traditional, full thickness cornea transplant (also known as penetrating keratoplasty, or PK) and back layer cornea transplant (also known as endothelial keratoplasty, or EK).
A graft replaces central corneal tissue, damaged due to disease or eye injury, with healthy corneal tissue donated from a local eye bank. An unhealthy cornea affects your vision by scattering or distorting light and causing glare and blurred vision. A cornea transplant may be necessary to restore your functional vision.
Corneal eye disease is the fourth most common cause of blindness (after cataracts, glaucoma and age-related macular degeneration) and affects more than 10 million people worldwide.*
More than 47,000 cornea transplants will be performed in the United States in 2013, according to an estimation by the Eye Bank Association of America. Since 1961, more than one million people have had their sight restored with a cornea transplant.
Diabetic retinopathy — vision-threatening damage to the retina of the eye caused by diabetes — is the leading cause of blindness among working-age Americans, according to the U.S. National Institutes of Health (NIH). Yet, many cases could be prevented with regular eye exams and appropriate treatment.
According to a report released by the International Diabetes Federation (IDF) at the World Diabetes Congress held in Vancouver in December 2015, the United States has the highest rate of diabetes among 38 developed nations, with approximately 30 million Americans — roughly 11 percent of the U.S. population between the ages of 20 and 79 — having the disease.
About 90 percent of Americans with diabetes have type 2 diabetes, which develops when the the body fails to produce enough insulin — a hormone secreted by the pancreas that enables dietary sugar to enter the cells of the body — or the body becomes resistant to insulin. This causes glucose (sugar) levels in the bloodstream to rise and can eventually damage the eyes, kidneys, nerves or heart, according to the American Diabetes Association (ADA).
Dry eye syndrome is a chronic and typically progressive condition. Depending on its cause and severity, it may not be completely curable. But in most cases, dry eyes can be managed successfully, usually resulting in noticeably greater eye comfort, fewer dry eye symptoms, and sometimes sharper vision as well.
Because dry eye disease can have a number of causes, a variety of treatment approaches are used.
The following is a list of dry eye treatments that are commonly used by eye doctors to reduce the signs and symptoms of dry eyes. Your eye doctor may recommend only one of these dry eye treatments or a combination of treatments, depending on the cause(s) and severity of your condition.
Also, some eye doctors will have you complete a questionnaire about your symptoms prior to initiating dry eye treatment. Your answers to this survey are then used as a baseline, and the questionnaire may be administered again after several weeks of treatment to evaluate the effectiveness of the chosen treatment approach.
Successful treatment of dry eyes requires that you are willing to follow your doctor’s recommendations and that you use the products he or she recommends consistently and as frequently as directed.
Eye allergies — red, itchy, watery eyes that are bothered by the same irritants that cause sneezing and a runny nose among seasonal allergy sufferers — are very common.
The American College of Allergy, Asthma and Immunology estimates that 50 million people in the United States have seasonal allergies, and its prevalence is increasing — affecting up to 30 percent of adults and up to 40 percent of children. In addition to having symptoms of sneezing, congestion and a runny nose, most of these allergy sufferers also experience itchy eyes, watery eyes, red eyes and swollen eyelids.
And in some cases, eye allergies can play a role in conjunctivitis (pink eye) and other eye infections.
If you think you have eye allergies, here are a few things you should know — including helpful tips on how to get relief from your red, itchy, watery eyes.
Eye floaters are those tiny spots, specks, flecks and “cobwebs” that drift aimlessly around in your field of vision. While annoying, ordinary eye floaters and spots are very common and usually aren’t cause for alarm.
Floaters and spots typically appear when tiny pieces of the eye’s gel-like vitreous break loose within the inner back portion of the eye.
When we are born and throughout our youth, the vitreous has a gel-like consistency. But as we age, the vitreous begins to dissolve and liquefy to create a watery center.
Some undissolved gel particles occasionally will float around in the more liquid center of the vitreous. These particles can take on many shapes and sizes to become what we refer to as “eye floaters.”
You’ll notice that these types of spots and eye floaters are particularly pronounced when you peer at a bright, clear sky or a white computer screen. But you can’t actually see tiny bits of debris floating loose within your eye. Instead, shadows from these floaters are cast on the retina as light passes through the eye, and those shadows are what you see.
You’ll also notice that these specks never seem to stay still when you try to focus on them. Floaters and spots move when your eye moves, creating the impression that they are “drifting.”
Glaucoma refers to a group of related eye disorders that all cause damage to the optic nerve that carries information from the eye to the brain. Glaucoma usually has few or no initial symptoms.
In most cases, glaucoma is associated with higher-than-normal pressure inside the eye — a condition called ocular hypertension. But it also can occur when intraocular pressure (IOP) is normal. If untreated or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to blindness.
According to the American Academy of Ophthalmology, the most common type of glaucoma — called primary open-angle glaucoma — affects an estimated 2.2 million people in the United States, and that number is expected to increase to 3.3 million by 2020 as the U.S. population ages.
And because most cases of glaucoma have few or no early symptoms, about half of Americans with glaucoma don’t know they have it.
Glaucoma is the second-leading cause of blindness in the U.S. (behind macular degeneration), and the second-leading cause of blindness worldwide (behind cataracts).
Hyperopia, or farsightedness, is a common vision problem, affecting about a fourth of the population. People with hyperopia can see distant objects very well, but have difficulty focusing on objects that are up close.
Hyperopia Symptoms and Signs
Farsighted people sometimes have headaches or eye strain and may squint or feel fatigued when performing work at close range. If you get these symptoms while wearing your eyeglasses or contact lenses, you may need an eye exam and a new prescription.
What Causes Hyperopia?
This vision problem occurs when . . .
Keratoconus is a progressive eye disease in which the normally round cornea thins and begins to bulge into a cone-like shape. This cone shape deflects light as it enters the eye on its way to the light-sensitive retina, causing distorted vision.
Keratoconus can occur in one or both eyes and often begins during a person’s teens or early 20s.
Keratoconus Symptoms and Signs
As the cornea becomes more irregular in shape, it causes progressive nearsightedness and irregular astigmatism to develop, creating additional problems with distorted and blurred vision. Glare and light sensitivity also may occur.
Often, keratoconic patients experience changes in their eyeglass prescription every time they visit their eye care practitioner.
What Causes Keratoconus?
New research suggests the . . .
Age-related macular degeneration, often called AMD or ARMD, is the leading cause of vision loss and blindness among Americans who are age 65 and older. Because people in this group are an increasingly larger percentage of the general population, vision loss from macular degeneration is a growing problem.
AMD is degeneration of the macula, which is the part of the retina responsible for the sharp, central vision needed to read or drive. Because the macula primarily is affected in AMD, central vision loss may occur.
About 1.75 million U.S. residents currently have advanced age-related macular degeneration with associated vision loss, with that number expected to grow to almost 3 million by 2020.*
Nearsightedness, or myopia, is the most common refractive error of the eye, and it has become more prevalent in recent years.
In fact, a recent study by the National Eye Institute (NEI) shows the prevalence of myopia grew from 25 percent of the U.S. population (ages 12 to 54) in 1971-1972 to a whopping 41.6 percent in 1999-2004.
Though the exact cause for this increase in nearsightedness among Americans is unknown, many eye doctors feel it has something to do with eye fatigue from computer use and other extended near vision tasks, coupled with a genetic predisposition for myopia.
Ocular hypertension means the pressure in your eyes — your intraocular pressure (IOP) — is higher than normal. Left untreated, high eye pressure can cause glaucoma and permanent vision loss in some individuals.
However, some people can have ocular hypertension without developing any damage to their eyes or vision, as determined by a comprehensive eye exam and visual field testing.
Researchers have estimated that ocular hypertension is 10 to 15 times more likely to occur than primary open-angle glaucoma, the most common type of glaucoma.
According to the Ocular Hypertension Treatment Study, 4.5 to 9.4 percent of Americans age 40 or older have ocular hypertension, which increases their risk of developing sight-threatening glaucoma.
A pinguecula (pin-GWEK-yoo-lah) is a yellowish, slightly raised thickening of the conjunctiva on the white part of the eye (sclera), close to the edge of the cornea.
Pingueculae are non-cancerous bumps on the eyeball and typically occur on top of the middle part of the sclera — the part that’s between your eyelids and therefore is exposed to the sun. Usually pingueculae affect the surface of the sclera that’s closer to the nose, but they can occur on the outer sclera (closer to the ear) as well.
“Pink eye” — It’s a term that may sound scary, but this common eye problem typically is easily treated and, with a few simple precautions, can often be avoided.
Anyone can get pink eye, but preschoolers, schoolchildren, college students, teachers and daycare workers are particularly at risk for the contagious types of pink eye due to their close proximity with others in the classroom.
Here are the essentials about pink eye (conjunctivitis) that you should know:
Presbyopia usually occurs beginning at around age 40, when people experience blurred near vision when reading, sewing or working at the computer.
You can’t escape presbyopia, even if you’ve never had a vision problem before. Even people who are nearsighted will notice that their near vision blurs when they wear their usual eyeglasses or contact lenses to correct distance vision.
Presbyopia is widespread in the United States. According to U.S. Census Bureau data, over 135 million Americans were age 40 and older in 2008, and the country is growing older: The median age reached 36.8 in 2008, up 1.5 years since 2000. This growing number of older citizens generates a huge demand for eyewear, contact lenses and surgery that can help presbyopes deal with their failing near vision.
More than a billion people in the world were presbyopic as of 2005, according to the World Health Organization, and 517 million of these did not have adequate correction with eyeglasses. In developing countries, glasses are available in urban areas, but in rural regions they are unavailable or expensive. This is unfortunate, because good near vision is important for literacy and for performing close-up work.
Ptosis (TOE-sis) refers to drooping of an upper eyelid of one or both eyes. The droop may be barely noticeable, or the lid can descend over the entire pupil. Ptosis can affect both children and adults, but usually occurs because of aging.
Ptosis Symptoms and Signs
The most obvious sign of ptosis is the drooping eyelid. Depending on how severely the lid droops, people with ptosis may have difficulty seeing. Sometimes people tilt their heads back to try to see under the lid or raise their eyebrows repeatedly to try to lift the eyelids.
The degree of droopiness varies from one person to the next. If you think you may have ptosis, compare a recent photo of your face with one from 10 or 20 years ago, and you’ll likely see a difference in the eyelid skin.
Ptosis can look similar to dermatochalasis, a group of connective tissue diseases that cause skin to hang in folds. These diseases are associated with less-than-normal elastic tissue formation. Your eye doctor should be able to tell whether or not this is the cause of your drooping eyelids.
Ptosis can be . . .
A detached retina is a serious and sight-threatening event, occurring when the retina becomes separated from its underlying supportive tissue. The retina cannot function when these layers are detached. And unless the retina is reattached soon, permanent vision loss may result.
Detached Retina Symptoms and Signs
If you suddenly notice spots, floaters and flashes of light, you may be experiencing the warning signs of a detached retina. Your vision might become blurry, or you might have poor vision. Another sign is seeing a shadow or a curtain descending from the top of the eye or across from the side.
These signs can occur gradually as the retina pulls away from the supportive tissue, or they may occur suddenly if the retina detaches immediately.
About one in seven people with sudden onset of flashes and floaters will have a retinal tear or detachment, according to a study reported in late 2009 in the Journal of the American Medical Association. Up to 50 percent of people who experience a retinal tear will have a subsequent detachment.
No pain is associated with retinal detachment. If you experience any of the signs, consult your eye doctor right away. Immediate treatment increases your odds of regaining lost vision.
Retinitis pigmentosa (RP) is a rare, inherited disease in which the light-sensitive retina of the eye slowly and progressively degenerates. Eventually, blindness results.
When retinitis pigmentosa is suspected, visual field testing likely will be conducted during or after your routine eye exams to determine the extent of peripheral vision loss. Other specialized eye tests may be needed to determine whether you have lost night or color vision.
A stye (medical term: hordeolum) develops when an oil gland at the edge of an eyelid becomes infected. Resembling a pimple on the eyelid, a stye can grow on the inside or outside of the lid.
Here are seven things to know about eye styes:
Uveitis (pronounced you-vee-EYE-tis) is inflammation of the uvea — the middle layer of the eye that consists of the iris, ciliary body and choroid.
Uveitis can have many causes, including eye injury and inflammatory diseases. Exposure to toxic chemicals such as pesticides and acids used in manufacturing processes also can cause uveitis.
The type of uveitis you have is classified by where inflammation occurs in the uvea:
- Anterior uveitis is inflammation of the iris (iritis) or the iris and ciliary body.
- Intermediate uveitis is inflammation of the ciliary body.
- Posterior uveitis is inflammation of the choroid.
- Diffuse uveitis (also called panuveitis) is inflammation of all areas of the uvea.
Many cases of uveitis are chronic, and they can produce numerous possible complications, including clouding of the cornea, cataracts, elevated eye pressure (IOP), glaucoma, swelling of the retina or retinal detachment. These complications can result in permanent vision loss.