The risks increase with a positive family history, hypertension, cardiovascular diseases, diabetes, smoking and alcoholism.

After entering the middle age group, in particular over 55, a routine check up of the eyes should be carried out every one or two years in order to initiate treatment during the early stages of the disease.

What is a cataract?

An opacified lens in the eye is a cataract. The eye is similar to a camera, light rays are focused by the lens onto the retina in order to form a sharp image. When a lens becomes opacified, the image formed could only be blurred. The commonest cause of cataract is aging; other causes include diabetes, trauma, inflammation and congenital.

Symptoms of cataract

The main symptom is blurriness of vision. Others may include glare under bright light, double vision in one eye, frequent change of glasses prescriptions, reduced dependence on reading glasses. The eye is not painful nor red unless in advanced cases with complications.

Could drugs prevent or treat cataracts?

While some medications may slow down cataract development, in order to prevent cataract formation one should avoid strong ultra-violet light exposure by the use of sunglasses.

Cataract extraction surgery

Surgery is the only treatment for cataract, and over 95% of patients can return back to normal vision after surgery. After the removal of cataract, an individualised intraocular lens implant will be fitted in place for best visual outcome. Usually this microscopic surgery is performed under local anesthesia and lasts less than half an hour. There is no need to stay in the hospital after surgery. If suitable, the cataract may be removed by ultrasound phacoemulsification. This minimally invasion approach ensures faster recovery due to a small wound size.

Does the cataract need to be dense before operation?

No, this approach is outdated. As the outcome for cataract surgery is excellent nowadays, the timing is based on visual needs. When eyesight has deteriorated affecting activities of daily living, then cataract surgery must be considered.

What is posterior capsular opacity?

Some patients experience visual deterioration a few years after cataract surgery. When a cataract was removed, its transparent capsule was left intact in order to support the intraocular lens implant. In some cases, the capsule may become opacified with time and vision is then affected. The opacified capsule can be reopened by a few laser shots, after which lights rays can again be focused sharply on the retina forming a clear image.

1. an increase in floaters
2. seeing flashes of light
3. development of a shadow like a curtain in the peripheral vision
4. blurring of vision

Who are more at risk of retinal detachment?

1. Those with thinning of the retina.
2. High myopia.
   
3. Strong family history.
   
4. History of trauma to the eye or head.
   

Can retinal detachment be prevented?

Retinal detachment cannot be prevented by medications. If retinal breaks are recognised early by an ophthalmologist through examination with pupil dilation, laser barrier or cryotherapy may be applied to seal off such breaks, thereby prevent the development of a retinal detachment. Therefore the most effective prevention is to be aware of the warning signs such as floaters and light flashes, and seek the help of an ophthalmologist promptly for a complete eye examination. For those with severe short-sightedness, it is advisable to avoid contact sports and have regular check ups.

Before and after illustrations of laser barrier therapy for retinal degeneration.

Retinal detachment is a serious situation and its repair surgery is complicated. The success rate may be up to 90%, but multiple interventions are sometimes required. There are largely two categories of surgeries: by the insertion of an explants onto the sclera in the form of a silicone band or buckle then application of cryotherapy to the retinal breaks, or by pars plana vitrectomy where the laser is applied to seal off the retinal breaks and gas may be injected in place of the vitreous removed in order to flatten the retina.

What are floaters?

Floaters are a symptom. While they can be caused by different diseases, the majority is due to vitreous condensation. The vitreous body is a transparent jelly like substance filling up the space between the lens and the retina; light rays pass through the vitreous and project onto the retina. With advancing age, the vitreous body contracts and detaches itself from the surface of the retina. Additionally the vitreous body may develop some opacities during this condensation process which form minor shadows onto the retina. These can be seen as dots, lines, small patches or spider web like.
On the other hand, other serious eye diseases like retinal tear, retinal detachment, vitreous haemorrhage due to diabetic retinopathy, uveitis can present with similar floaters. Therefore prompt examination by an experienced ophthalmologist is mandatory.

Can floaters be cured?

         There are some medications that may reduce the vitreous condensations.
       

Glaucoma

Glaucoma is usually caused by raised intraocular pressure leading to visual loss.

When the drainage channels are blocked, fluid trapped inside the eye leads to elevated intraocular pressure. Such pressure damages the optic nerve head causing irreversible visual deterioration and eventually blindness.

Glaucoma may be subdivided into chronic, acute, secondary and congenital:

1. Chronic Glaucoma

This is the commonest type of glaucoma. At the early stage, only the peripheral visual field is affected, hence frequently overlooked. If uncontrolled, visual loss will eventually affect central vision.

The risk of chronic glaucoma rises with advancing age, usually develops over the age of 35 and sometimes runs in the family.

During the early stages, patients with chronic glaucoma do not have any symptoms. When the intraocular pressures become high, patients may experience some swollen sensation in the eye with headache, hazy vision and halo when looking at lights.

The diagnosis of glaucoma requires clinical examinations of the optic nerve heads, visual fields and intraocular pressures.

Chronic glaucoma can be treated and controlled. As it cannot be eradicated, observation and treatment are required for life. Permanent visual damage can be avoided if glaucoma is detected and treated early.

2. Acute Glaucoma

Acute glaucoma occurs when the aqueous drainage channels are blocked within a short period of time. Pressure inside the eye quickly builds up due to the trapped fluid. Symptoms may include aching pain in the eye, headache, blurring of vision, seeing halo, nausea and vomitting. The immediate treatment aim is to reduce the intraocular pressure, after which treatment will be directed to manage complications such as recurrence and chronic glaucoma. The fellow eye will require medications or laser therapy to prevent similar glaucoma attack.

3. Secondary Glaucoma

Secondary glaucoma occurs due to other eye diseases, such as iritis, eye injury, mature cataract, prolonged steroid usage and diabetes. Treatments of both glaucoma and the underlying diseases are required.

4. Congenital Glaucoma

This kind of glaucoma is found in newborn. Symptoms may include watery red eyes, high sensitivity to light, squint and cloudy large corneas. Early surgery is mandatory.

What is maculopathy?

The central region of the retina is the macula. When there is pathological
changes in the macula, central vision will be distorted and blurred. In
maculopathy, fine vision and reading will be affected most, while peripheral
vision is preserved. Frequently such changes are related to ageing, where
it is known as age related macular degeneration.
Age related macular degeneration usually occurs after the age of 50, and it
is a major cause of permanent blindness after the age of 60. At the early
stages, the symptoms experienced may not be very obvious. If the
maculopathy is the educative type however, vision may deteriorate rapidly
during the two years after diagnosis, leading to blindness.

Two types of age related macular degeneration

1. Dry type

Commoner, with lesser visual deterioration
Yellow white druses spots in the macula
Slow progression
May worsen and develop wet type

2. Wet type (exudative)

Abnormal blood vessels grow within the macula region, where exudation and
blood may accumulate
Severe worsening of vision, usually irreversible

What are the causes of age related macular degeneration?
It is usually found in patients over the age of 50, more with advancing age,
but no sexual predominance. The retinal degenerates with thinning causing
deterioration of macular function. Possible factors include familial
history, dietary habit, smoking, exposure to excessive radiation,
cardiovascular diseases and anxiety.

Treatment of maculopathy

The latest treatment is by photodynamic therapy. A photosensitizing agent is injected which will attach onto the abnormal blood vessels. A low energy laser is then applied locally onto the affected area, and those treated abnormal vessels will stop growing and leaking. The advantages are that there is no damage to the retina and there is no scar formation.

1. Regular self examination using the Amsler Grid.
2. Flourescein Angiography

Flourescein angiography examines the retinal blood vessels by taking photographic images of the vessels at different time intervals after an injection of dye.

Procedure:

• Under adequate lighting, place the Grid at 30 cm distance from the eyes.
  
• Wear adequate spectacle correction or reading glasses if required.
  
• With the left eye covered, fixate the right eye onto the central spot on the grid.
  
• While fixating at the central spot, note if there is any distortions or defects with the grid.
  
• Repeat with the left eye.
  
• Any distortion may an early warning sign and must be checked by the doctor quickly.