Vision Information - Common Eye Disorders
Patients often become quite anxious when told they need a corneal graft and worry about what this involves.
The cornea can be likened to a window that is in front of the eye. Light enters the eye through the clear cornea passing through the clear lens to focus on the retina at the back of the eye. If injury or disease damages or deforms the cornea, the path of light to the retina becomes distorted and vision is impaired.
What is a Corneal Graft
A corneal graft is an operation in which part of the cornea is removed and replaced with a similar section from a donor eye.
Why Have a Corneal Graft?
The cornea assists in the focusing and transmission of light. If this is interfered with through injury, and general eyewear and medication cannot help, then a corneal graft may be performed to:
Diabetes is a disease that affects many people and can have adverse consequences for the eye.
The Effect of Diabetes
Blood sugar fluctuations can cause changes in the focussing of the crystalline lens within the eye and result in poor vision. It can also cause cataracts in young people and accelerate the development of cataracts in older people.
Diabetic retinopathy is a common cause of blindness in people between the ages of 30-65 and, at any one time, around 10% of people with diabetes will have retinopathy and require treatment.
Can Retinopathy be prevented?
If your diabetes is rigorously controlled, the risk of contracting retinopathy can be reduced by 60% in type 1 (insulin dependent) and 40% in type 2 (non-insulin dependent) diabetes.
Though most diabetics who have had the condition for a long period will have some degree of retinopathy, eye checks can enable early diagnosis and treatment.
When Should My Eyes be Examined?
It is recommended that people with insulin dependent diabetes should have their eyes examined when diagnosed with the condition or within four years after contracting it. Thereafter, regular annual eye checks are advised. Those with non-insulin dependent diabetes should be tested when diagnosed and at least annually thereafter.
How is Diabetic Retinopathy Treated?
Early detection and treatment is naturally the best and is done with laser photocoagulation to seal off leaking blood vessels and destroy new growth. The procedure is painless because the retina does not contain nerve endings.
In some patients the blood may leak into the vitreous humor and cause cloudy vision. The eye doctor may wait for it to dissipate on its own but, if necessary, a procedure called a vitrectomy, which removes blood that has leaked into the vitreous humor, will be carried out.
If diabetic retinopathy has caused your body to form a cataract, it can be corrected surgically. Patients who have contracted glaucoma should see a glaucoma specialist.
Your eye care practitioner will provide comprehensive advice on the status of your condition and what to do about it.
Some people complain of shapes that drift across their vision. The form of these shapes varies and is sometimes small dots or small irregularly shaped strands. These shapes are called floaters.
What Causes Floaters?
The vitreous is a jelly-like substance that fills the eye and, as it ages, protein strands called collagen become visible within it. When the eye moves, the strands gently swirl and give rise to the shifting shapes seen by patients. Flashes of bright white light can also occur that may indicate posterior vitreous detachment, which can lead to retinal detachment.
As a rule, you should not be concerned at seeing one or two floaters drift across your vision. But a sudden increase in the number of floaters, particularly if accompanied by white flashing lights, should raise an alarm and prompt an immediate visit to your eye doctor to examine for possible retinal detachment.
Can Floaters be Removed?
Floaters can be removed through an operation called a vitrectomy, which removes the vitreous. The procedure does carry significant risks which include retinal detachment and cataracts, and many eye surgeons are reluctant to recommend this surgery unless there is a threat to sight.
When a separation occurs between the retina and the wall at the back of the eye, a retinal attachment developments. An operation is necessary to return the detached retina to its position.
Symptoms of Retinal Detachment
Patients often describe a "curtain", "flashing lights", "something black" or a cobweb. In older people this doesn't necessarily indicate a serious problem, but the sudden appearance of floaters or bright white flashes of light requires a comprehensive eye examination to rule out the presence of retinal holes or tears.
What Causes Retinal Detachment?
Most retinal detachments develop because of a hole or tear in the retina that occurs when the retina becomes thin (in short-sighted people), or if the vitreous separates from the retina. An injury to the eye or a cataract operation may also cause it.