Here are some common eye diseases:
• Cataract
• Glaucoma
• Diabetic Retinopathy
• Lazy Eye (Amblyopia)
Cataract
A cataract is a condition in which the clear lens of the eye becomes cloudy, preventing sufficient light rays from entering the eye and impairing vision.
Cataract is not a tumour or a growth over the eye as is commonly feared. It is normally a part of the ageing process and is due to the physical changes taking place in the lens. A common condition among the elderly, cataracts can also be caused by injury, be present at birth or due to illnesses such as diabetes.
Symptoms
The first sign is usually a blurring of vision which cannot be corrected by glasses. Opacification, or clouding, nearly always develops at the edges of the lens and if progressive, impairs vision as it spreads inwards. Other symptoms may include seeing multiple images, poor vision in bright light, seeing a large black spot in front of the eye or haloes around lights.
Treatment
At present, there is no recognised or effective treatment for cataracts once they become advanced, apart from surgery. Depending on the patients needs, and as long as vision remains satisfactory, surgery is not necessary. However, your surgeon will advise that the cataract be removed when poor vision interferes with your daily activities.
Cataract microsurgery is usually highly successful and more than 90% of patients are able to regain good vision. With the removal of the cloudy lens, an artificial lens is needed to substitute its function of focusing light rays onto the retina. This is achieved in one of three ways by special cataract glasses, contact lenses or intraocular implants which are plastic discs inserted into the eye.
* This is a general guide. If in doubt, please consult your doctor.
Glaucoma
Glaucoma accounts for 40% of blindness in Singapore. It is an eye disease where the fluid pressure within the eyeball is too high and damages the optic nerve, which carries visual impulses from the eye to the brain. This pressure build-up occurs because of an imbalance between the production and drainage of fluid within the eyeball.
Glaucoma is damaging to sight because the raised pressure can injure the delicate nerve fibres contained in the retina and the optic nerve at the back of the eyeball.
The vast majority of cases develop slowly, and the patient is normally not aware of the gradual loss of sight until very late in the disease when vision is seriously affected.
Symptoms
Depending on the type of glaucoma, various symptoms may be experienced. There is gradual loss of peripheral (ie side) vision and night vision. Central reading vision is usually affected only at late stages. Eye pain, redness, headache, nausea and vomiting can occur in certain types of glaucoma. Blurred vision and coloured rings around lights accompany these symptoms. You are advised to see your doctor if you experience any of these symptoms.
Treatment
The earlier glaucoma is diagnosed, the greater the chances of success in preventing visual loss. Assessment for glaucoma is easily carried out in the clinic and is painless. It includes the measurement of eyeball pressure, optic nerve examination, an assessment of the fluid drainage channels of the eyeball, and a test to chart the area of the vision that each eye can see.
Although glaucoma cannot be cured, in most cases it can be successfully controlled. The treatment depends on the type of glaucoma. It may be in the form of medication (eg eyedrops), laser therapy or surgery. Your doctor will discuss with you the best treatment in your case.
It is important to note that the success of treatment for glaucoma is measured by the stability of the condition, which only your eye doctor can determine. The degree of sharpness of your vision does not indicate how well the glaucoma is controlled. Patients should therefore continue with regular check-ups with your eye specialist to ensure that everything is well, and to detect early worsening of the glaucoma to prevent visual loss.
* This is a general guide. If in doubt, please consult your doctor.
Diabetic Retinopathy
Diabetic retinopathy is a disorder of the retinal blood vessels resulting from diabetes mellitus. Diabetic retinopathy is the leading cause of new blindness in working adults in developed countries. The trend is also becoming similar in Singapore. The incidence of diabetic retinopathy increases with the duration of diabetes. About 60% of patients having diabetes for 15 years or more will have some blood vessel damage in their eyes and a percentage of these are at risk of developing blindness.
Treatment
Control of blood sugar and blood pressure are important but progression of retinopathy may occur despite all medical efforts. If diabetic retinopathy is detected early, photocoagulation by laser photocoagulation may stop continued damage. Even in advanced stages of the disease, it can reduce the chance that a patient will have severe visual loss.
Successful treatment of diabetic retinopathy depends on early detection and treatment. All diabetics are advised to control their diabetes with diet and medication to delay or prevent the development of diabetic retinopathy and other complications. They are also advised to undergo a yearly eye examination.
* This is a general guide. If in doubt, please consult your doctor.
Lazy Eye (Amblyopia)
Amblyopia is commonly known as lazy eye. This should not be confused with squints. Amblyopia is poor vision in an eye that did not develop normal sight during early childhood. After the age of four years, the development of the part of the brain that processes vision is almost complete. If the brain has not received clear images from the weak eye, it would be difficult to improve the vision in this eye after the brain is completely developed. The eye is then said to be amblyopic or lazy.
Lazy eye is commonly caused by short-sightedness, long-sightedness or astigmatism; Large differences in refractive power between the two eyes, squint or obstruction of vision by droopy eyelid, cataract or other lesions.
Treatment
To correct amblyopia, the child must be forced to use the lazy eye. This is usually done by patching or covering the good eye, often for weeks or months. If the child also requires spectacles, he must wear it all the time.
The basis of patching is to allow the amblyopic eye to be used more often than the other eye so that it gets a chance to develop normal vision. The recovery of vision is better if patching is done at a very early age, preferably before 4 years old.
Successful treatment depends on how severe the amblyopia is and the age of the child when treatment is begun. If the problem is detected early, successful treatment is possible and treatment time is shorter. If it is detected after the age of four, the success rate would be very low.
Since the child is usually too young to complain of poor vision, this detection requires early checking of the vision by the family doctor, paediatrician or ophthalmologist before three years of age.
* This is a general guide. If in doubt, please consult your doctor.