Be on guard against these eye ailments that can develop without warning

Cataracts

A cataract is a clouding of the lens in the eye, causing vision to become blurry and colours dull.  Cataracts occur mainly due to age so they are difficult to prevent.  However, there are steps you can take to delay their onset, such as wearing sunglasses and not smoking.  Prolonged exposure to ultraviolet light and smoking both increase the risk of cataracts.

In most cases, clear vision can be restored by surgically removing the clouded lens and replacing it with a clear artificial lens. The current standard procedure, called phacoemulsification, involves an incision in the eye of only 1.8mm to 3.2mm, which heals without stitches.

A bonus of cataract surgery is that patients can get problems like myopia and presbyobia corrected at the same time. They can choose from a range of lens implants the newer multifocal lenses can correct myopia and presbyobia simultaneously.  However, some patients are not suitable for multifocal implants, for example those who have previously undergone Lasik or have dry eyes.

While multifocal lens will allow patients to do without glasses for both near and distant vision, their distant vision will not be as sharp as people with monofocal implants.  They may also experience glare and haloes at night, but this usually lessens over a few months as the brain adjusts to the new lens.

Associate Professor Chee Soon Phaik, co-head of Cataract Service and head of Ocular Inflammation & Immunology Service at Singapore National Eye Centre (SNEC), says : “There are many patients with multifocal lens implants who have become spectacle independent and are extremely satisfied with their outcome.  These findings are based on SNEC’s audit of multifocal implant results.”

Dr Bobby Cheng from Singapore Eye and Vision, says : “The key to patient satisfaction and good surgical outcome is patient selection and good preoperative counseling to manage patient expectation and assess the patient’s suitability for the newer lens options.”

Glaucoma

Glaucoma destroys vision so slowly and painlessly – beginning with peripheral vision and progressing to the centre – that by the time its victims notice that something is wrong, irreversible damage has already been done.  It is caused by a build-up of pressure in the eye that damages the optic nerve transmitting information from the eye to the brain.  About 3 per cent of Singaporeans over 40 have glaucoma.  The proportion increases to about 10 per cent among those above 70.

Glaucoma can affect anyone but those at higher risk include people with a family history of the disease, users of steroids, and those with extreme short- or long-sightedness, past trauma to the eyes, diabetes, high blood pressure, migraine and advanced cataracts. 

“Unfortunately, the vast majority of glaucoma cannot be prevented by a change in lifestyle or diet.  Only in a few types of glaucoma caused by other diseases may a change in lifestyle and diet reduce risk,” says Dr Ho Ching Lin, head, Glaucoma Service (Clinical) at SNEC. 

The key to preventing blindness lies in early detection and treatment of glaucoma.  All those at risk of glaucoma should get their eyes checked regularly.  When glaucoma is detected, the majority of patients can be treated with eye drops or oral medications to reduce the internal pressure in the eye and prevent further damage to the optic nerve.  Other treatment options are laser therapy and surgery.  However, patients will need life-long follow-up and medication as there is no cure for glaucoma.

Age-related Macular Degeneration (AMD)

The macula, located at the centre of the retina, is responsible for sharp, central vision.  In advanced cases of AMD, the macula deteriorates to the point that the patient loses all central vision and sees only a black patch in the centre of his visual field.  In Singapore, the overall risk of getting AMD is about 5 per cent. 

The risk increases with age – rising from 8 per cent in the 60 to 69 year age bracket to about 16 per cent for those in the 70 to 79 bracket.  Smokers and those with a history of AMD in the family, excessive exposure to ultraviolet light, obesity and cardiovascular disease are at higher risk of getting AMD.  If AMD hits, an early symptom is that straight lines appear wavy, but people often miss the signs.

“The reason is that if one eye is affected, we tend to use our good eye.  It is only when both eyes are affected, or if we one day close our good eye, that we realize something is wrong,” says Dr Chan Choi Mun from SNEC’s Vitreo-Retinal Service. 

Hence, regular monitoring of vision is important to detect AMD early.  AMD is usually treated with anti-VEGF (vascular endothelial growth factor) injections into the eye to impede the growth of abnormal blood vessels in the macula that cause vision loss.  Other treatments include using a light-activated drug to destroy the abnormal blood vessels (photodynamic therapy) or using laser to do so.