Vision health in sharp focus

  • Metro News
  • Monday, 25 Nov 2019

EYESIGHT influences all aspects of our lives.

“Losing one eye equates to losing 25% of one’s functional capability, while losing both eyes means losing 85% of a person’s functional capabilities, ” revealed ParkCity Medical Centre consultant ophthalmologist and glaucoma surgeon Dr Lee Ming-Yueh.

“Your eyes are your most important sense organ. The eyes monopolise 65% of the pathways to the brain, 75% of all sensory input to the brain, ” she shared at a StarLIVE talk titled “Glaucoma: Early detection is better than later” held at Menara Star in Petaling Jaya.

The talk was organised by Star Media Group Bhd and Ramsay Sime Darby.

Dr Lee, who has 25 years of experience in medical practice and 13 years as an eye specialist, said glaucoma was the second major cause of blindness.

“If a person has been diagnosed with having glaucoma, he or she can become blind. Blindness is indefinite if left untreated, ” she said, adding that research estimated there would be 80 million glaucoma patients worldwide in 2020 while 11 million were expected to become blind from glaucoma.

Dr Lee said blind people would lose their jobs or earning capacity and this would have a significant impact on quality of life.

“They are also more prone to falls and accidents, depression and sickness.”

She said glaucoma was a chronic eye disease with progressive damage of the optic nerve.

“The optic nerve is the important nerve that carries the images captured by the eyes to our brain for perception of vision.

“At birth, each eye has about 1.2 million of nerve fibres in the optic nerve, ” Dr Lee explained.

She said a regular eye produced fluid called aqueous to bring in oxygen and nutrients to nourish the structure inside the eye.

“Then the fluid is drained out of the eye through the angle of the eye (the drainage canals are at the peripheral where the iris and cornea meet). Glaucoma develops when the eye’s drainage canals become blocked and the pressure inside the eye rises.

“Increased eye pressure damages the optic nerve directly by mechanical force and indirectly by impairing its blood supply.

“As individual nerves are damaged, there will be less information transmitted to the brain. The nerve loss is irreversible, there is no way to grow new nerves to replace the damaged ones, ” she said.

According to Dr Lee, there are two types of primary glaucoma.

She said primary open-angle glaucoma accounted for almost 70% to 80% of all glaucoma cases, and primary angle closure glaucoma, which contributed to about 15% to 20%.

Primary open-angle glaucoma, she added, was a painless gradual loss of vision.

“Primary angle closure glaucoma can have very dramatic presentation because of a sudden rise in eye pressure.

“Patients usually come to the emergency room with painful red eyes associated with blurry vision, severe headache, nausea and vomiting. It is often misdiagnosed as conjunctivitis, migraine and gastritis.

“Eye pressure is usually very high; more than 50mmHg and this is an emergency because blindness can occur within a few hours if not treated immediately. This phenomenon is called acute angle closure attack, ” she said, adding that primary angle closure glaucoma contributed up to 80% of all glaucoma blindness.

Dr Lee said there was also secondary glaucoma, which could be caused by uncontrolled diabetes and hypertension.

“Secondary glaucoma usually requires surgery, ” she noted.

She also highlighted that most patients who suffered from glaucoma had no symptoms at the early stages.

“In the early stage, glaucoma causes gradual constriction of visual field (the area that one can see) without affecting the clarity of the image they see.

“The patients are unlikely to notice it because they still can read and watch television or do computer work; and driving a car is not a problem, ” she said.

She said the disease could be uncovered with early eye examination to detect early damage.

“Blurring of vision only occurs at the very advanced stage and blindness follows quickly.

“It is totally irreversible. That is why glaucoma is infamously called ‘the sneak thief of sight’, ” she added.

Dr Lee said childhood glaucoma presented differently compared to glaucoma in adults.

“Small children do not complain. Their problem is often reported by parents who notice their child’s persistent tearing.

“The child’s eye may also appear hazy and become larger than the regular eye, ” she said.

On who was at risk of developing glaucoma, she said it depended on multiple factors, including high eye pressure (normal eye pressure is between 10 to 21mmHg), age (the risk increases with age), race (certain races are prone to different types of glaucoma), family history (risk is 10 times more for those with first degree relative with glaucoma), high refractive error (very short-sighted or very long-sighted), systemic diseases (diabetes, hypertension, migraine, sleep apnoea syndrome), steroid use for long periods of time and eye injury.

On management of glaucoma, Dr Lee said it was very individualised, adding that it could involve medical treatment (such as eye pressure lowering eyedrops), laser treatment and surgery.

Her colleague, consultant and paediatric ophthalmologist Dr Norazah Abdul Rahman spoke about “Lazy eye or Amblyopia.”

Dr Norazah, who has been practising medicine for 19 years, said lazy eye meant disorder of visual system during infancy or early childhood.

“Lazy eye is usually unilateral (one eye), but can be affecting both eyes (bilateral), ” she said.

Causes of amblyopia, she said, included high refractive error in an eye (when one eye cannot focus well because of a problem with its shape), different refractive power in both eyes, misalignment of the eyes (strabismus) and blocking of the visual pathway such as cataract and droopy eyelids.

She said treatment would depend on the cause and could include corrective glasses to achieve a clear image, forcing the lazy eye to work by means of patching the good eye, eye drops to blur the image of the good eye, surgery to realign the squint eye (which costs between RM7,000 and RM15,000) and use of the latest dichoptic binocular software games and special goggles to stimulate both eyes for vision improvement.

Dr Norazah said most amblyopic vision loss was preventable or reversible with timely detection and appropriate intervention.

“It is caused by disturbance of vision during a critical or sensitive period of visual development.

“It should be identified at a young age when prognosis for successful treatment was best.

“Screening for amblyopia can be easily performed with vision screening programme, ” she added.

Administrative manager Petronila Maurice said the talk was informative as she found that diabetics had a higher risk of getting glaucoma.

Dr Amirah Mohd Nor, a medical officer from Taiping Hospital, said the talk was useful and easy to understand.

“I have much better knowledge of eye diseases now and can explain them to patients, ” she added.

Retiree Wong Hung Way, 61, said the talk provided valuable tips and new insight on the topic while the content was well organised and easy to follow.

The audience also took part in a question-and-answer session with both speakers after the talk, followed by free vision and eye pressure checks.

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