Cataracts
Cataracts are a clouding of the lens within the eye, which causes lack of vision and can lead to blindness. The clouding affects the crystalline lens of the eye, and is particularly common in aged people (called senile cataracts) and is considered an age-related eye disease.
Bilateral cataracts in an infant due to Congenital rubella syndrome
If untreated, cataracts can cause a person to lose perception of certain colors (usually blue) and can lead to vision loss.
Cataracts:
• Various causes including genetics, diabetes, radiation exposure, trauma and denaturation of lens protein
• Affects central vision
• Can cause blindness if left untreated
• Can be cured with surgery and prevented with certain vitamins
Normal vision Vision with cataract
Cataracts:
• Various causes including genetics, diabetes, radiation exposure, trauma and denaturation of lens protein
• Affects central vision
• Can cause blindness if left untreated
• Can be cured with surgery and prevented with certain vitamins
Normal vision Vision with cataract
Cataracts affect over 18 million people worldwide, and are the leading cause of blindness in some underdeveloped countries.
Predominant in elderly people, cataracts affect over 40% of people between 52 and 64 and more than 60% of people over the age 65. Some statistics show a 90% prevalence of cataracts in the elderly over the age of 90.
Cataracts are caused, as mentioned, by the denaturation of proteins in the crystalline lens of the eye. The crystalline lens is located behind the cornea (the bulge on the outer front of the eye) and the aqueous humor (the liquid pocket behind the cornea).
The lens is made of various elements including water and proteins which are important for the lens’ structure and flexibility, and are arranged in such a way to focus light onto the retina at the back of the eye.
Certain triggers can cause the proteins to ‘cloud’ causing loss of visions and the onset of a cataract. A good analogy of this is the proteins in the ‘white’ of an egg. Initially clear, if you add heat to the egg white, it will start to cloud until, with enough heat, it becomes completely white (opaque).
Denaturation of the proteins in the crystalline lens works the exact same way. The triggers, however, are numerous and not completely understood by medical research.
Heat and thermal trauma to the eye can cause a cataract in exactly the same way an egg white turns white. Other factors, particularly radiation, can cause the proteins to cloud over. Other causes have been related to allergies, ultraviolet light (or severe sun exposure), corticosteroid use and vitamin deficiencies.
Cataracts can appear and never get worse (stationary cataracts) or can progressively get worse even if the assumed cause has been isolated and eliminated (progressive cataracts).
Unlike many age-related eye diseases, cataracts can be treated and cured through surgery. In many cases, the lens of the eye is actually replaced by a plastic lens which is impervious to protein denaturation. When surgery is performed, lenses are created that will also cure certain sight issues, particularly short sightedness, which can be a symptom of cataracts.
Like many eye diseases, research has shown that proper nutrition and the intake of daily recommended vitamins such as Vitamin A, C and E may help to prevent cataracts. Studies are now being done on the efficacy of these antioxidants. It should be noted that the use of ultraviolet protecting sunglasses can help reduce the chance of getting a cataract, or slow the progression of a cataract.
What are the symptoms of a cataract?
The most common symptoms of a cataract are:
• Cloudy or blurry vision.
• Colors seem faded.
• Glare. Headlights, lamps, or sunlight may appear too bright. A halo may appear around lights.
• Poor night vision.
• Double vision or multiple images in one eye. (This symptom may clear as the cataract gets larger.)
• Frequent prescription changes in your eyeglasses or contact lenses.
• These symptoms also can be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.
Diabetic Retinopathy
Predominant in elderly people, cataracts affect over 40% of people between 52 and 64 and more than 60% of people over the age 65. Some statistics show a 90% prevalence of cataracts in the elderly over the age of 90.
Cataracts are caused, as mentioned, by the denaturation of proteins in the crystalline lens of the eye. The crystalline lens is located behind the cornea (the bulge on the outer front of the eye) and the aqueous humor (the liquid pocket behind the cornea).
The lens is made of various elements including water and proteins which are important for the lens’ structure and flexibility, and are arranged in such a way to focus light onto the retina at the back of the eye.
Certain triggers can cause the proteins to ‘cloud’ causing loss of visions and the onset of a cataract. A good analogy of this is the proteins in the ‘white’ of an egg. Initially clear, if you add heat to the egg white, it will start to cloud until, with enough heat, it becomes completely white (opaque).
Denaturation of the proteins in the crystalline lens works the exact same way. The triggers, however, are numerous and not completely understood by medical research.
Heat and thermal trauma to the eye can cause a cataract in exactly the same way an egg white turns white. Other factors, particularly radiation, can cause the proteins to cloud over. Other causes have been related to allergies, ultraviolet light (or severe sun exposure), corticosteroid use and vitamin deficiencies.
Cataracts can appear and never get worse (stationary cataracts) or can progressively get worse even if the assumed cause has been isolated and eliminated (progressive cataracts).
Unlike many age-related eye diseases, cataracts can be treated and cured through surgery. In many cases, the lens of the eye is actually replaced by a plastic lens which is impervious to protein denaturation. When surgery is performed, lenses are created that will also cure certain sight issues, particularly short sightedness, which can be a symptom of cataracts.
Like many eye diseases, research has shown that proper nutrition and the intake of daily recommended vitamins such as Vitamin A, C and E may help to prevent cataracts. Studies are now being done on the efficacy of these antioxidants. It should be noted that the use of ultraviolet protecting sunglasses can help reduce the chance of getting a cataract, or slow the progression of a cataract.
What are the symptoms of a cataract?
The most common symptoms of a cataract are:
• Cloudy or blurry vision.
• Colors seem faded.
• Glare. Headlights, lamps, or sunlight may appear too bright. A halo may appear around lights.
• Poor night vision.
• Double vision or multiple images in one eye. (This symptom may clear as the cataract gets larger.)
• Frequent prescription changes in your eyeglasses or contact lenses.
• These symptoms also can be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.
Diabetic Retinopathy
Retinopathy generally means damage to the retina.
Diabetic retinopathy is damage to the retina caused by the effects of diabetes mellitus. Diabetic Retinopathy affects almost 80% of people who have had diabetes for more than 10 years. Although diabetic retinopathy may not always cause blindness, the symptoms of the eye disease can come and go very quickly, often overnight.
Diabetic Retinopathy affects people with both Type I and Type II diabetes.
Retinopathy:
• blood vessels in the eye weakening and/or hemorrhaging due to diabetes mellitus
• can affect central or peripheral vision or both
• can cause blindness if left untreated
• can be treated with surgery or certain steroids
When a person has diabetes, their blood vessels (particularly the smaller vessels like those in the eye) can become weakened and prone to hemorrhaging due to over-accumulation of blood sugar (glucose/fructose).
When the blood vessels at the back of the eye are weakened, they cannot provide proper nutrients to the retina. At this stage, called nonproliferative diabetic retinopathy (NPDR), the person may experience a blurring of the vision but in many cases will not notice any change in their vision.
Once the blood vessels are weakened enough, they start to hemorrhage. The resulting fluids can then obstruct the macula, causing a condition called macular edema (swelling of the macula) and cause blurring vision.
Proliferative Diabetic Retinopathy (PDR) occurs when NPDR advances to the point where lack of oxygen to the retina (caused by weakened or hemorrhaging blood vessels) stimulates the growth of new blood vessels directly on the retina.
The new blood vessels will cause blurred vision. If the blood vessels then start to bleed (as is common), the resulting fluid can block the retina (causing spotted vision or complete loss of sight), and can actually damage the retina or cause it to detach.
PDR can be treated in a variety of ways, but it cannot be cure and must be frequently monitored to make sure the retina is not being damaged. Some surgeries, such as laser surgery, can be used to eliminate new blood vessels growing on the retina.
0 comments:
Post a Comment