Herpes Zoster Shingles
One's first encounter with the herpes zoster virus is usually childhood chicken pox. Later in life, the virus may reactivate, causing a characteristic rash of small blisters, frequently on the chest or forehead, which form crusts and may leave scars. This second encounter with the virus is commonly known as shingles. Unlike chicken pox, shingles...
Smoking and the Eye
Tobacco smoking is directly linked to many adverse health effects, including high blood pressure, heart disease, and cancer. Smoking is also linked to eye disease. How does smoking affect the eyes? People who smoke cigarettes are at increased risk for developing cataracts, a clouding of the naturally clear lens of the eye. Cataracts cause a...
Complete Eye Exam
A complete eye examination does more than determine how clearly you see from a distance and which lens prescription, if necessary, will give you the best possible vision. If you have never had an eye examination or are seeing your ophthalmologist for the first time, you will be asked questions about your medical history, your family’s...
Recycling Eyeglasses
The World Health Organization estimates that corrective lenses can improve the eyesight of one-fourth of the world’s population. Unfortunately, for many people a pair of eyeglasses is both unaffordable and unobtainable. The donation of old but useful eyeglasses to the needy in Canada and abroad can help solve this problem. The Lions Clubs International and...
How to Use Eyedrops
Infections, inflammation, glaucoma, and many other eye disorders often are treated with medicated eyedrops. It is important to remember that all medicines can have side effects. Surprisingly, even the small amount of medication in an eyedrop can create significant side effects in other parts of the body. There are ways to decrease the absorption rate...
Computer Screens
Complaints of eye discomfort and fatigue are becoming more common as the use of computer screens increases. While it is true that computer screens can cause eyestrain, there is no convincing evidence that they can harm the eyes. Some people fear that computer screens emit damaging ultraviolet (UV) light or radiation. The amount of UV...
Contact Lenses
Contact lenses are thin, clear, disks of plastic that float on the tear film that coats the cornea, the clear front window of the eye. Contact lenses are used to correct the same conditions that eyeglasses correct: myopia (nearsightedness); hyperopia (farsightedness); astigmatism; and presbyopia. Hard Contact Lenses Most kinds of hard contact lenses are rarely...
Viewing a Solar Eclipse
Looking at a solar eclipse is as dangerous as staring at the unblocked sun and can cause damage to the retina, the light-sensitive nerve layer at the back of the eye. The damage affects the macula, the part of the retina responsible for fine central vision. Many people think they can protect their eyes by...
Sunglasses
Sunglasses are popular for comfort and fashion, but now there is medical evidence supporting the use of sunglasses to protect the long-term health of the eyes by limiting their exposure to ultraviolet (UV) light. More than a dozen studies have shown that spending hours in the sun without proper eye protection can increase the chances...
Eyeglasses
Eyeglass lenses compensate for an eye that is too long or too short by adding or subtracting focusing power. The lenses create just the right amount of focusing power so light rays focus directly on the retina. A plus (+) in front of the first number of the eyeglass prescription means the lens corrects farsightedness....
Legal Blindness
Normal vision, or 20/20 vision, means that a person can read the smallest letters or see the pictures on an eye chart when standing 20 feet away from the chart. Some people cannot see normally even with eyeglasses or contacts because a medical condition affects their vision. These people are called visually impaired or visually...
Floaters and Flashes
Small specks or clouds moving in your field of vision as you look at a blank wall or a clear blue sky are known as floaters. Most people have some floaters normally but do not notice them until they become numerous or more prominent. In most cases, floaters are part of the natural aging process....
Colour Blindness
Colour blindness (colour vision deficiency) is a condition in which certain colours cannot be detected. There are two types of colour vision difficulties: congenital (inherited) problems that you have at birth, and problems that develop later in life. People born with colour vision problems are unaware that what they see is different from what others...