Symptoms of Glaucoma

One type of glaucoma, acute angle-closure glaucoma, does produce noticeable symptoms. In angle-closure glaucoma, there is a rapid buildup of pressure in the eye (intraocular pressure, known as IOP), which may cause any of the following:

• blurred vision
• severe eye pain
• headache
• haloes (which may appear as rainbows) around lights
• nausea and vomiting

Angle-closure glaucoma is a rare, but serious, form of the disease. If you have any of these symptoms, call your optometirst or ophthalmologist immediately. Unless treated quickly, blindness can result.

TYPES OF GLAUCOMA
The most common form of glaucoma is open-angle glaucoma. In open-angle glaucoma, the aqueous, or fluid, that normally flows through the pupil into the anterior chamber (the front section of the eye's interior) cannot get through the trabecular meshwork (the eye's filtration area) to the normal drainage canals. This causes a buildup of pressure in the eye (intraocular pressure, or IOP), which can damage the optic nerve and lead to vision loss.

Most people who develop open-angle glaucoma notice no symptoms until vision is impaired.

In acute angle-closure glaucoma there is a sudden increase in intraocular pressure (IOP) due to the buildup of aqueous in the eye.

Acute angle-closure glaucoma is considered an emergency because optic nerve damage and subsequent vision loss can occur within hours of the onset of the problem. Symptoms of this kind of glaucoma can include nausea and vomiting, seeing haloes around light, and pain in the eye.

Chronic angle-closure glaucoma, like open-angle glaucoma, may cause vision damage without symptoms.

Although angle-closure glaucoma is unusual, people of Asian or Innuit ancestry are at higher risk of developing it. As with other forms of glaucoma, age and family history are also risk factors, and the problem seems to occur in older women more often than others.

Both open-angle and angle-closure glaucoma can be primary or secondary. A primary condition is one that cannot be attributed to any known cause. A secondary condition can be traced to another cause, such as previous injury or illness.

"Normal (or low) tension" glaucoma is an unusual and poorly understood form of the disease. In this type of glaucoma, the optic nerve is damaged even though the patient's intraocular pressure is consistently within a range usually considered normal.

Childhood glaucoma is rare, and starts in infancy, childhood or adolescence. Like open-angle glaucoma, there are few, if any, symptoms in the early stage, and blindness can result if it is left untreated. Like most types of glaucoma, this type of glaucoma is thought to have a hereditary component.

Congenital glaucoma is a type of childhood glaucoma that usually appears soon after birth, although it can become apparent later in the first year of life. Unlike other childhood glaucomas, congenital glaucoma often has noticeable signs, including tearing, light sensitivity, and cloudiness of the cornea. This type of glaucoma is more common in boys, and can affect one or both eyes.

Your Optometrist or Ophthalmologist may tell you that you're a glaucoma suspect if you have one or more risk factors for glaucoma. These may include elevated intraocular pressure (IOP), family history, ethnic background, older age, optic nerve appearance, and other factors.

Elevated IOP is sometimes called ocular hypertension. This means that your IOP is higher than what is considered "normal." A diagnosis of ocular hypertension does not mean you have glaucoma, but it does mean you're at increased risk, and should probably have frequent medical eye examinations. Sometimes your Optometrist or Ophthalmologist will recommend medication to lower your IOP.

Treatment for glaucoma may include medication and/or surgery.
Visit http://www.glaucoma.org for more infomation

Normal cornea

Reflection of circular ring onto cornea

Astigmatic cornea

Reflection of circular ring onto astigmatic cornea

Explanation:

Think of the normal cornea as being round, or spherical, with both horizontal and vertical curvature the same (two arrow diagram above).

Think of astigmatism as if the cornea was pinched along the single arrow, or A. The circular ring reflection hits a plane of the cornea at the flatter curvature B before it does the steeper curvature at A that is further down - closer to the corneal base before reflecting onto the cornea there (further from the surface before reflected surface reached because it is pinched, or steeper vertically and the ring reflection hits a point further down). This creates an OVAL reflection - and visually a "streak effect". (The reflection has a smaller chord diameter along A (further away) and larger at B (closer)). This cornea would be described as having + cylinder at 90 degrees, or - cylinder at 180 degrees.

Alternative Names
Lens Opacity

Definition
A cloudy area in the lens of the eye.

Causes, incidence, and risk factors
The lens of an eye is normally clear. If the lens becomes cloudy or is opacified it is called a cataract. Cataracts may be present at or shortly after birth in which case they are called congenital cataracts. Adult cataract develops with advancing age, tends to run in families, and the appearance may be accelerated by environmental factors. Cataract may develop at any time throughout life following an eye injury in which the capsule of the lens is damaged. Cataract may also develop in response to metabolic diseases such as diabetes

Congenital cataracts are cataracts which are present from birth (or appear shortly after). They may be familial (autosomal dominant inheritance), or they may be caused by congenital infections such as rubella, or associated with metabolic disorders such as galactosemic. Risk factors include inherited metabolic diseases, a family history of cataract, and maternal viral infection.

Adult cataract is generally associated with aging. It develops slowly and painlessly with a gradual loss of vision. Visual problems may be heralded by difficulty seeing at night, halos around lights or glare when looking at lights, and finally, decreased visual accuity, even in daylight.

Adult cataracts are classified as immature, mature, or hypermature. A lens that has some remaining clear areas is referred to as an immature cataract. A mature cataract is completely opaque; a hypermature cataract has a liquefied surface that leaks through the capsule and may cause inflammation.

Most people develop some clouding of the lens after the age of 60. About 50 percent of Canadians ages 65 to 74 have cataract and about 70 percent of those age 75 and over have it. Most people with cataract have it in both eyes, although one eye may be worse than the other. Many people with cataract don't even know they have it.

Other factors that may contribute to cataract development are low serum calcium levels, diabetes, long-term use of corticosteroids, and other inflammatory and metabolic disorders. Other causes include trauma, radiation exposure, and excessive exposure to ultraviolet light (sunlight). In many cases, the cause of cataract is unknown.

Treatment
OVERVIEW:
Cataract treatment is done simply to improve vision. For some people changing their glasses, getting stronger bifocals, or using a magnifying lens is helpful enough. Others choose to have cataract surgery.

If you are not bothered by a cataract, then treatment is usually not necessary. On occasion, there may be an additional eye problem that the doctor needs to see or treat and the cataract impairs the doctors view. In these cases, cataract surgery may be required to allow proper treatment of the other eye problem.

SURGERY :
Cataract surgery consists of removing the lens of the eye and replacing it with an artificial one. Your doctor will discuss the options with you and together you will decide which type of removal and lens replacement is best for you.

LENS REMOVAL
There are 3 different types of surgery that can be used to remove lenses that have a cataract.

Extracapsular surgery consists of surgically removing the lens, but leaving the back half of the capsule (the outer covering of the lens) intact.

Phacoemulsification is done by softening the lens with sound waves and then removing it through a needle. The back half of the lens capsule is left behind.

Intracapsular surgery involves surgically removing the entire lens, including the capsule. This is done very rarely.

LENS REPLACEMENT
People who have cataract surgery usually get an artificial lens at the same time. The artificial lens is a plastic disc called and intraocular lens. It is placed in the lens capsule inside the eye.

Other options include contact lenses and cataract glasses. You and your doctor will decide which choice is best for you.

Surgery can be done in an outpatient center or hospital, and you can leave when your doctor says you are fit to go. Most people do not need to stay overnight in a hospital. You will need a friend or family member to take you home and someone will need to stay with you for a day or two to help you follow your doctor's instructions.

It takes a few months for an eye to heal totally so your doctor should check your progress periodically and make sure you have the care you need until your eye fully recovers.

Alternative Names
diabetes; sugar diabetes

Definition
A disorder caused by decreased production of insulin or by decreased ability to use insulin. Insulin is a hormone produced by the pancreas that is necessary for cells to be able to use blood sugar.

Causes, incidence, and risk factors

The cause of diabetes mellitus is unknown, but heredity and diet are believed to play a role in its development. Diabetes results when the pancreas produces insufficient amounts of insulin to meet the body's needs. It can also result when the pancreas produces insulin, but the cells are unable to efficiently use it (insulin resistance). Insulin is necessary for blood sugar (glucose) to go from the blood to the inside of the cells, and unless the sugar gets into the cells, the body cannot use it. The excess sugar remains in the blood and is then removed by the kidneys. Symptoms of excessive thirst, frequent urination, and hunger develop. The (metabolism) of carbohydrates, fats, and proteins is altered.

Diabetes occurs in several forms. The most common types are: Type I, or insulin-dependent diabetes mellitus (IDDM); Type II, or non-insulin-dependent diabetes mellitus (NIDDM); and Gestational Diabetes Mellitus.

Insulin-dependent diabetes mellitus (IDDM or Type I) usually occurs in people before the age of 30 requires insulin injections to live. Risk factors for IDDM include autoimmune disease, viral infections, and a family history of diabetes.

Noninsulin-dependent diabetes mellitus (NIDDM or Type II) usually occurs in severely overweight (obese) adults and rarely requires insulin treatment. Treatment includes diet for diabetics and exercise. Risk factors for Type II are obesity, physiological or emotional stress, pregnancy, certain medications, age over 40, and family history.

Gestational diabetes starts or is first recognized during pregnancy. It usually becomes apparent during the 24th to 28th weeks of pregnancy. In many cases, the blood-glucose level returns to normal after delivery. Risk factors for gestational diabetes are maternal age over 25 years, family history of diabetes, obesity, birth weight over 9 pounds in a previous infant, unexplained death in a previous infant or newborn, congenital malformation in a previous child, and recurrent infections.

Diabetes mellitus affects up to 5% of the population in the Canada, almost 1.4 million people.

Vision abnormalities - Diabetes and The Eye

Definition
Blurred vision is the loss of visual acuity or sharpness resulting in unclear visual details. Vision loss is the inability to perceive visual stimuli. Blind spots are apparent dark "holes" in the visual field in which nothing can be seen. An enlarging blind spot is growth in the size of a blind spot that is readily apparent to the individual.

Alternative Names
decreased vision; diminished eyesight; blindness, temporary; impaired vision; eyesight diminished

Call your Optometrist if

• any sudden visual changes occur
• there is partial or complete blindness in one or both eyes
• there is trouble seeing objects to either side (decreased peripheral vision) or if halos are seen around lights.
• blind spots suddenly appear

Common Causes

• aging, (the most common cause of decreased vision)
• cataracts (also common in the elderly)
• glaucoma
• complications of diabetes (the most common cause of blindness in the North America)
  • intermittent or fixed double vision (usually temporary)
  • retinal hemorrhages, which can cause more permanent blindness
  • diabetic retinopathy
  • eye infection, inflammation, or injury
  • infections of the cornea that cause scarring, distortion or perforation
  • nfections of the retina with viruses, fungi or parasites--seen with increasing frequency in AIDS
  • floaters (tiny particles) drifting across the eye usually are harmless and require no treatment
  • fatigue and prolonged exposure to the outdoors (temporary and reversible blurring of vision)
  • drugs (blurring, spots, and halos)
  • anticholinergics
  • antihistamines
  • clomiphene
  • chloroquine
  • cycloplegic
  • digitalis derivatives (temporary)
  • ethambutol
  • guanethidineo indomethacin
  • methanol toxicity (permanent)
  • phenothiazines
  • phenylbutazone
  • quinine sulfate
  • reserpine
  • thiazide diuretics

• migraine headaches (spots of light, halos, or zigzag patterns are common preliminary symptoms)
• congenital disorders
• heritable disorders

What to expect at your Optometrists office.

The medical history will be obtained and an examination performed.

Medical history questions documenting the vision abnormalities in detail may include:

• time pattern
  • When did this begin?
  • Did it occur suddenly or gradually?
  • Does it occur only occasionally? How often?
  • How long does it last?
  • When does it occur? Evening? Morning?
• quality
  • Is the vision blurred or is there double vision?
  • Are there blind spots?
  • Are there areas that look black and missing?
  • Is side vision missing?
  • Are halos (circles of light) seen around shiny objects or lights?
  • Are flashing lights or zigzag lines seen?
  • Is extreme sensitivity to light present?
  • Do stationary things seem to be moving?
  • Are colors missing?
  • Is it difficult to differentiate colors?
  • Is there pain?
  • Is there drainage from the eye(s)?
  • Are the eyes crossed?
  • Does one of the eyes "drift"? Do both?
  • location
  • Is the problem in one eye or both eyes?
• aggravating factors
  • Have you had any of the following in the last few weeks to months?
    • injury
    • infection
    • increased stress
    • anxiety
    • depression
    • fatigue
    • headache
    • exposure to pollens, wind, sunlight, or chemicals
    • use of soaps, lotions, or cosmetics
• relieving factors
  • Is your vision better after you rest?
  • Is it better with corrective lenses
  • other
  • What other symptoms are also present?
    • redness
    • swelling
    • bruising
    • headache
    • pain
    • itching
    • a sense that something is in the eye
    • increased tearing
    • decreased tearing

• additional important information
  • What medications are being taken?
  • Is there a family history of diabetes?
  • Have you had a previous head injury?
  • Do you have any allergies?
  • Has there been a loss of eyelashes?

The examination will include an eye examination. The Optometrist will check vision, eye movements, pupils, back of the eye, and eye pressure when indicated.

Diagnostic tests that may be performed include:

• slit-lamp examination
• refraction test
• tonometry

Intervention:
Surgery will be recommended for some conditions (such as cataracts or muscle problems). Diabetics must control their blood-sugar level. Other treatments depend on the cause.

Home Care
Safety measures may be necessary to help a person with vision abnormalities. For example, it may be helpful to increase the amount of light in a room.

• Considerations
  Loss of visual acuity, changes in vision, blurriness or decreased light perception should always be evaluated as soon as possible by a medical professional. Changes may represent primary eye disease, aging, eye trauma, or a generalized (systemic) illness. Whatever the cause, visual changes should never be ignored. Decreased vision is a significant threat to the quality of life. Professional help is always indicated, but which professional to see is often a question.