Eye is like a camera. Light enters the eye through a small hole called the pupil and is focused on the retina. Eye also has a lens, which focuses images from different distances on the retina. The colored ring of the eye, the iris, controls the amount of light entering the eye. A tough white sheet called sclera covers the outside of the eye. Front of the sclera is transparent, to allow the light to enter the eye, the cornea. Image formed on the retina is transmitted to brain by optic nerve.
Common Vision Problems:
The most common vision problems are refractive errors, more commonly known as nearsightedness, farsightedness, astigmatism and presbyopia. The length of the eyeball (either longer or shorter), changes in the shape of the cornea, or aging of the lens prevents light from focusing directly on the retina which cause refractive errors. Presbyopia affects most adults over age 35. Other refractive errors can affect both children and adults. Individuals that have parents with certain refractive errors may be more likely to get one or more refractive errors discussed below:
• Nearsightedness (Myopia) is a condition where objects up close appear clearly, while objects far away appear blurry. With nearsightedness, light comes to focus in front of the retina instead of on the retina.
• Farsightedness (Hyperopia) is a common type of refractive error where distant objects may be seen more clearly than objects that are near. Some people may not notice any problems with their vision, especially when they are young.
• Astigmatism is a condition in which the eye does not focus light evenly onto the retina. This can cause images to appear blurry and stretched out.
• Presbyopia is an age-related condition in which the ability to focus up close becomes more difficult. As the eye ages, the lens can no longer change shape enough to allow the eye to focus close objects clearly.
Signs and Symptoms of Refractive Errors:
Blurred vision is the most common symptom of refractive errors. Other symptoms may include:
• Double vision
• Glare or halos around bright lights
• Eye strain
Diagnosis & Treatment of Refractive Errors:
An eye care professional can diagnose refractive errors during a comprehensive eye examination. They can be corrected with eye glasses, contact lenses or surgery.
Age-Related Eye Diseases:
As age advances, vision changes, glasses are needed to see close objects or there is trouble in adjusting to glare or distinguishing some colors. These changes are normal. But as you age, you are at higher risk of developing age-related eye diseases discussed below:
• Cataract: A cataract is a clouding of the lens in the eye. Vision with cataract can appear cloudy or blurry, colors may seem faded and you may notice a lot of glare. It needs to be corrected surgically.
• Diabetic Eye Disease: Diabetic eye disease is a complication of diabetes and a leading cause of blindness. The most common form is diabetic retinopathy which occurs when diabetes damages the tiny blood vessels inside the retina.
• Glaucoma: Glaucoma is a group of diseases that can damage the eye’s optic nerve and result in vision loss and blindness. It is usually associated with high pressure in the eye and affects side or peripheral vision.
• Age-related Macular Degeneration: It is a disease associated with aging that gradually destroys sharp, central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving.
• Dry Eye: Dry eye occurs when the eye does not produce tears properly, or when the tears are not of the correct consistency and evaporate too quickly. Dry eye can make it more difficult to perform some activities, such as using a computer or reading for an extended period of time.