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Advancing cataract surgery through bladeless femtosecond laser technology

Approved by the US FDA in 2010, femtosecond laser cataract surgery is 100 per cent bladeless and represents a new wave of advancement in the field of cataract surgery. Manual phacoemulsification cataract surgery, on the other hand, has not changed much in more than 50 years — it is still performed by human hand and blades to cut the cornea, needles and forceps to tear the lens capsule inside of the eye. In this case, the cataract has to be manually sculpted inside the eye, requiring greater energy that causes more corneal endothelial cell loss and more inflammation to the eye.

The traditional method is dependent on human’s estimation of depth and manual dexterity to prevent intra-operative complications. In advanced bladeless laser cataract surgery, a cold femtosecond laser replaces the human hand to make corneal incisions, the circular opening of the lens capsule, and breaks up the cataract — all in less than 60 seconds. With Artificial Intelligence programming abilities, the laser gives a higher precision, predictability, and reproducibility than manual phacoemulsification surgery. It uses real-time spectral domain optical coherence tomography (OCT) scans to accurately pre-program incisions at different levels within the eye, and then perform all these incisions in a bladeless fashion under total computer guidance. The laser’s ability to break up the cataract in just 30 seconds means that the cataract is removed with less energy inside the eye compared to manual phacoemulsification technique. This enables rapid visual recovery and is also more beneficial for the long term biomechanical strength of the cornea due to reduced corneal endothelial cell loss.

Benefits of 100 per cent bladeless laser femtosecond laser cataract removal and computer-guided intra-ocular lens implantation include: 3D-Imaging performs more than 10,000 real time OCT scans to produce high resolution images to guide the surgery Software customises a plan for bladeless incisions and division of the cataract to suit the eye Precise femtosecond laser pulses are used, no sharp instruments involved An ultrasound tip removes the cataract fragments using minimal energy settings Computer-guided lens implantation system enables insertion of lens implant to near-perfect alignment and accurate centration This technology automates and safeguards some of the more challenging steps of surgery, offering better lens implant centration, greater precision for multifocal lens implant visual outcome and minimizing the chances of intra-operative complications caused by human errors.


 

 

 

 

 

 

 

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Correcting presbyopia with a new generation of IOLS for cataract surgery

 

Modern cataract surgery patients have high expectations for their postoperative vision, with many desiring spectacle freedom. In the last decade, premium Intraocular Lenses (IOLs) that replace cataracts also allow correction of presbyopia, myopia, and astigmatism. Surgeons can now help patients achieve optimal vision with presbyopia-correcting IOLs by matching available technologies with patients’ needs.

Multifocal IOLs When it comes to visual function, 3 key distances to take note of are: 35 cm for reading, 66 cm for intermediate vision, and 6 m for distance. To achieve them without glasses, multifocal IOLs or trifocal IOLs are often used.

However, they may cause night-time glare and halos in the first few months.

Extended Depth of Focus (EDOF) IOLs For people who do not want glare and halos, but desire good far and intermediate vision and are willing to wear reading glasses for prolonged reading, options include Extended Depth of Focus (EDOF) IOLs. These have an elongated focal area, providing extended depth of focus EDOF multifocal IOLs provide clear far and intermediate vision with reasonably clear near vision, causing less glare and halos postoperatively compared to multifocal or trifocal IOLs, but the near vision is not as strong.

Monofocal / Monofocal Plus IOLs

Can patients achieve spectacle independence with standard monofocal IOLs? Yes. Monovision provides spectacle freedom by correcting the dominant eye to zero dioptres(D) for distances whilst the non-dominant eye is made -1.75D for reading. Monovision provides good far and near vision, however, intermediate vision may not be as good as with multifocal, trifocal, or EDOF IOLs. Monofocal Plus IOLs are monofocal IOLs that carry extra power to enhance the intermediate (66cm) zone of monovision. Mono Plus IOLs give better binocular intermediate vision than standard monofocal IOLs, yet is without the glare and halos associated with multifocal IOLs.

Bladeless Femtosecond (FS) Laser Cataract surgery using FS laser replaces blades and manual cutting by hand. The biggest advantage is that it allows perfect centration of the IOL to the centre of visual axis. 3D optical coherence tomography scans and laser precision create perfectly sized and circular capsule openings for IOLs. FS laser capsulotomies attain reproducible, uniformly circular and precise diameter compared to manual capsulotomies, improving refractive outcomes of multifocal/EDOF IOLs and maximising patients’ chances of achieving total spectacle independence.

THE STRAITS TIMES
THE STRAITS TIMES MONDAY, NOVEMBER 26, 2018
ASK THE EXPERTS
Brought to you by
DR NATASHA LIM
EYE CENTRE




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Am I too old for LASIK?

 

I have just turned 40. Recently, I find %2Cmy vision fluctuating between clear and blur when I wear contact lenses. It is more blurred in dim light conditions. Is LASIK still suitable for me or am I too old for it? Are there any other options?

ALASIK is a type of refractive surgery that offers patients a permanent alternative to wearing glasses or contact lenses. It is a life-changing procedure that has been around since 1991 and has been performed on more than 40 million people worldwide. The procedure is all laser and 100 per cent bladeless. A very thin flap on the cornea is first created using a femtosecond laser, then an excimer laser re-shapes the underlying corneal tissue to correct short-sightedness, astigmatism and long-sightedness or presbyopia (“lao hua”).

Advanced and safer technology

Technology has advanced greatly, patient satisfaction is at an all-time high, and studies have demonstrated exceptional safety outcomes. With careful patient selection and ul-tra-thin flaps made by the bladeless ferntosecond laser, post -op dry eyes are only temporary and no longer pose a long-term issue in most patients, while ectasia (loss of corneal strength) is now very rarely seen. Patients get their vision back the next day and can quickly return to their work and activities. It is the most commonly performed la-ser eye surgery worldwide and, at present, remains the mainstay of refractive surgery for the treatment of short-sightedness, astigmatism and long-sighted-ness/presbyopia.

Suitable age group

The United States Food and Drug Administration (FDA) has approved LASIK for those aged 18 and above, with no upper age limit. Although the majority of LASIK patients at our eye centre are between l8 and 50 years old, there are also others in their 60s and 70s who come to have presbyopia corrected by LASIK if they did not have the opportunity to get their presbyopia corrected during their previous cataract surgeries. The FDA approved treatment range for LASIK includes up to -12.00 dioptres (D) of myopia, +6.00D of long-sighted-ness/presbyopia and -6.00D of astigmatism.

Demand for better visual quality

Patients today not only expect 20/20 vision or better after LASIK surgery, they also demand better quality of vision than what they have with spectacles and con-tact lenses. For example, a 20-year-old patient may see well in the daytime but finds that his glasses or contact lenses are associated with glare and haloes at night and generally blurry vision in dim light conditions. These are visual quality issues rather than visual quantity issues — things that make patients like or dislike their own eyes, enjoy or not enjoy their own vision — and are termed Higher Order Aberrations (HOAs). HOAs occur mostly in dim light conditions, when the pupil automatically dilates in the dark and allows much more light rays to enter the eye. These light rays encounter impurities inside the eye’s fluid and get scattered instead of being able to focus onto the retina to provide a clear image, causing night-time optical disturbances such as glare, haloes, starbursts and blur.

Wavefront-guided LASIK

The most advanced form of HOA correction is wavefront-guided LASIK. This technology originated from the National Aeronautics and Space Administration (Nasa) Hubble Space Telescope, considered to be the most powerful optical device ever invented by mankind to date.

Besides reducing or eliminating total dependence on glasses, the technology also has the potential to improve night-time quality of vision. This was the reason Nasa and the US Navy lifted the ban on LASIK surgery back in 2007, approving specifically wavefront-guided LASIK treatments only to be performed on astronauts and naval pilots.

Scientific evidence in the US showed that for people involved in vision-critical jobs, wavefront-guided LASIK was not only safe and effeCtive, it also enabled many patients to achieve even better improved night-time visual acuity and night-time contrast sensitivity than their glasses or contact lenses.

In 2003, FDA approved the use of cus-tomised wavefront-guided technology using VISX Custom-Vue of iLASIK.

The goal of iDesign iLASIK surgery is no longer to equal the best glasses or contact lenses, but to actually exceed the quality of vision of glasses or contact lenses by treating existing night-time vi-sual disturbances.

The highest form of wavefront-guided LASIK surgery, which applies Fourier al-gorithm calculations, can offer very high quality or superior night-time quality of vision in different lighting conditions.

SMILE procedure

Small incision lenticule extraction (SMILE) is a new laser vision proce-dure, where a piece of carved tissue is re-moved manually from inside the cornea through a 2mm to 3mm corneal incision. For patients with a larger amount of myopia, the piece removed will be thick-er and deeper compared to a mild correc-tion. While the incision on the cornea is smaller, the invasion depth in the cornea is the same as LASIK and it should also be avoided for patients with chronic or pathological dry eyes. Visual recovery from SMILE is longer than LASIK and can even take a month or so.

SMILE is currently FDA-approved to treat between -1.00D and -8.00D of my-opia with up to -3.00D of astigmatism, so it is not yet a solution for patients with long-sightedness/presbyopia or mixed astigmatism. It is also not able to perform custom-ised treatment for HOAs that affect night vision, and remains a treatment based on spectacle prescription only.

Implantable Collamer Lenses Implantable Collamer Lenses (ICL) are the ideal solution for patients with high prescriptions not suitable for laser eye surgery. The FDA-approved age range is 21 to 45 years old, and the FDA-approved treatment range is up to -20.00D of short-sightedness, up to +12.00D of long-sightedness and up to -5.00D of astigmatism.

THE STRAITS TIMES
DECEMBER 22 2011


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Ageing eyes causing blurry vision

 

Q) I have presbyopia and am looking for a treatment to solve my problem. What is the best option? Should I wear spectacles or have surgery? How reliable is presbyopia surgery?

A) Presbyopia (lao hua yan) affects everyone from the age of 40 onwards. It causes progressive difficulty in the ability to focus when reading and or looking at near objects.

As the eye ages. there is loss of elasticity in the crystalline lens and loss of power of the ciliary muscle to automatically contract and relax the crystalline lens for focusing, resulting in presbyopia. This weakening process inside the eye gets worse with age.

Some patients cannot adjust to progressive glasses and must deal with the inconvenience of constantly switching between regular and reading glasses.

Others are bothered by the psychological stress of ageing. which is confounded by the need for unattractive bifocal glasses.

Contact lenses can cause discomfort. exacerbate dry eye (a condition common in people above 50 years old): and raise the risk of potentially vision-threatening infections. such as bacterial corneal ulcers.

Many new technologies have emerged in the market in recent years. Examples are PresbyLasik, corneal inlays and Intracor. But many of them are not approved by the US Food and Drug Administration (FDA).

The FDA-approved methods for treating presbyopia are mono-vision Lasik. mono-vision cataract surgery and multi-focal cataract surgery. Younger patients with presbyopia but no cataracts may opt for Lasik – a type of eye surgery that uses a laser to change the shape of the cornea thereby treating any refractive errors such as myopia, astigmatism and presbyopia. One of the first FDA-approved surgical options for presbyopia correction is mono-vision Lasik. where one eye is laser-corrected for distance vision, and the other eye is laser-corrected for near vision. To a large extent, binocular vision is preserved, so you have adequate depth perception for driving, for instance. But one eye sees more clearly in the distance. and the other eye sees better up close.

The 10-minute painless procedure is done under topical anaesthetic eyedrops, and short-sightedness. astigmatism and presbyopia will be “zapped” away by a laser. Dry eyes may be a temporary side effect for two to three months after the operation. However. most people will experience a lower degree of dry eye after recovery. compared with when they wore contact lenses previously. Another option is the implantable contact lens (ICL), but this is not FDA-approved for patients above 45 years old as the internal environment of the eye starts to change at that age. And the ICL. which is a foreign body in the eye, stands a greater chance of removal if it encroaches too close to the natural lens or the iris, which can cause cataracts or glaucoma. respectively.

CATARACT WOES

Similar to presbyopia. the development of cataracts is also inevitable as part of the ageing process. Cataract surgery – the insertion of a presbyopia-correcting lens implant – kills two birds with one stone by providing clearer vision as well as correcting myopia, astigmatism and presbyopia at the same time. Therefore. older patients with presbyopia and cataracts should opt for cataract surgery instead.

There is a choice between monofocal or multifocal lens implants to replace the natural lens that has turned cloudy. Both are able to treat refractive errors (such as myopia, astigmatism and presbyopia). There is no .need to wear spectacles after the procedure. The procedure takes 15 minutes per eye, and can also be performed using only topical anaesthetic eyedrops. High-definition lens implant materials are available to enhance contrast sensitivity and provide high quality vision for the ageing eye. Meanwhile. monovision cataract surgery involves implanting a monofocal lens in one eye that is set for near vision, while the other eye is implanted with another monofocal lens that is set to see objects at far distances. The brain takes a few weeks to get used to monovision, after which the person becomes unaware which eye is focused on near objects and which is focused on faraway things. Those who tried out monovision trial lenses in the clinic and did not like it should opt for multi-focal cataract surgery. Multifocal lens implants can provide the eye with both a distance-focus and a near-focus at all times. They are similar to progressive glasses, but without the need to look up and down to switch between far and near focus. Your brain will adapt to the multi-focal visual system after the operation. You may consider presbyopia surgery if you are not satisfied with glasses or contact lens wear. The advantages of presbyopia surgery include spectacle freedom from most daily tasks. a high success rate and the possibility of further enhancement of your vision with spectacles when necessary.

 


Two ways to correct ‘lao hua’

 

Q I have just turned 50 and reading is getting more difficult. Are there any permanent treatments for presbyopia?

A) Muscles which control the crystalline lens inside an eye automatically relax when we look at faraway objects and contract when we look at small objects close up. This enables the lens to provide the correct focusing power for far and near vision.

When a person is around the age of 40, the muscles within the eyes start to weaken in their ability to contract and expand the lens, losing focus for near objects.

Moving your reading material further away from your eyes can help as it adjusts the focus point of your eyes.

Around the age of 50, the lens start to develop early cataract changes, becoming cloudier and inelastic.

The combination of weakened muscles and inelastic lens makes reading glasses a requirement at this age.

Many people with presbyopia (“lao hua”) still wish to enjoy all the five zones of human vision (see graphic, right) without spectacles.

The first option is mono-vision, using Lasik surgery to correct one eye’s focus for far vision (Zones Four and Five) and correct the other eye’s focus for near vision (Zones One and Two).

The brain then merges the two images, producing “blended vision” to achieve intermediate vision (Zone Three), thus enabling you to see relatively well at all distances.

To make sure you can adapt to this kind of vision, you would experience mono-vision with simulation lenses at the clinic before having a more permanent surgical procedure.

Lasik mono-vision does not prevent cataract formation.

By the age of 60, everyone with or without past Lasik experience would likely face blurred vision caused by cataracts and may require cataract surgery.

Normal cataract surgery can be performed in post-Lasik eyes and the new lens implant inserted during cataract surgery can correct presbyopia once again.

Your second option is cataract surgery and lens implantation. It is a one-time procedure without the need for repeat cataract surgery.

Refractive cataract surgery replaces a cloudy lens with a multi-focal lens implant to correct presbyopia.

Associated short-sightedness, long-sightedness and astigmatism are also treated completely, allowing you to be spectacle-free for all five zones of vision. This is a 15-minute, pain-free procedure.

Both options may cause a slight drop in the quality of distance vision, but it is not visually debilitating.

Many people feel it is a worthwhile trade-off in order to enjoy life without using spectacles and retain near vision after middle age.


 

Lasik no issue for cataract op

 

Q: I am 33 years old. I was told that if I do Lasik now, I will have problems doing cataract surgery in future when I am older. Is that true?

A: This is not true. Successful cataract surgery is possible for people who have had laser-assisted in-situ keratomileusis (Lasik).

The surgical success rate would be exactly the same as that of an eye that has never had Lasik, as it is technically not any more different or difficult to perform cataract surgery on a post-Lasik eye than it is on a virgin eye.

Lasik is a type of refractive surgery that corrects common vision problems, such as myopia (short-sightedness), astigmatism (when the eye surface is not round but resembles a rugby ball) and presbyopia (long-sightedness).

The corrective surgery enables the person to see clearly without spectacles.

In 1999, the United States Food and Drug Administration approved Lasik for use in the US and the technique quickly gained popularity with patients.

Today, Lasik is the single most common refractive procedure in the world, with over 40 million procedures performed.

Whether you have had Lasik or not, everyone develops cataracts around the age of 60. This is due to the ageing process of the natural lens inside each of our eyes.

Given that Singapore has one of the highest rates of myopia in the world, many cataract patients here may have had Lasik in the past. These patients would still wish to remain spectacle-free after their cataract surgery.

Some eye surgeons may say that the results of cataract surgery in post-Lasik eyes are unpredictable. They may want old records of your eye measurements before Lasik surgery.

In the past, the calculation formula for lens implant power used during cataract surgery was based on the pre-Lasik spectacle prescription and cornea curvatures.

But advances in calculation formula, cataract surgery techniques and lens implants in the last 10 years have entirely changed the landscape of refractive surgery. Several advanced mathematical formulas have emerged, and these are used for precise calculation of lens implant power in post-Lasik eyes. The modern and more accurate formulas require no prior data at all.

Additionally, they provide greater refractive accuracy.

This allows surgeons to use premium lens implants for total correction of astigmatism and multi-focal implants for presbyopia correction in post-Lasik eyes.

New and innovative mono-focal and multi-focal lens implant designs to correct presbyopia can now improve refractive outcomes without sacrificing visual quality.

For those who have had mono-vision Lasik in their 40s and are used to it, it is advisable for them to maintain mono-vision, by undergoing cataract surgery with mono-vision lens implants.

Mono-vision is where one eye is corrected for seeing far distances while the other eye is corrected for near vision.

But some patients will opt for multi-focal lens implants. It is a misconception that multi-focal lens implants cannot be used in post-Lasik eyes. Highly specialised refractive surgeons who handle both Lasik and cataract surgery are able to achieve accurate results and good outcomes with multi-focal implants.

This has been shown by many published studies worldwide.

Today, patients’ vision can be dialled back a few decades in time, even if they have had an earlier Lasik procedure.

THE STRAITS TIMES
FEBRUARY 2 2012

 


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Options for eyesight correction

Q My daughter is 21 years old and has -8.00 dioptres of short-sightedness in both eyes. She wears contact lenses to correct her vision. Is it better to use Lasik or implantable collamer lenses (ICL) to correct her short-sightedness permanently?

A) Both Lasik and 1CL surgery are safe and reliable. Neither one is superior to the other. A surgeon who is skilled to perform both will advise patients which is the preferred method for them and why.

BASICS OF LASIK

Lasik uses a beam of light from an excimer laser to gently reshape the outer window of your eye, known as the cornea. When wavefront technology is used, the laser reshapes the cornea with minimal impact on its natural profile. This reduces the risk of post-operative glare and haloes at night, and can improve the prospects of vision performance. When non-wavefront technology is used, the laser reshapes the treatment zone of the cornea only, but does not blend this new profile into the non-treated area, giving more chances of glare and haloes at night post-operatively. Lasik can treat up to -12.00 dioptres of short-sightedness, -6.00 dioptres of astigmatism and +5.00 dioptres of long-sightedness. The procedure is approved by the United States Food and Drug Administration (FDA) for those aged 18 years and above. Most patients develop some degree of dry eyes immediately after the procedure, but this is temporary. Artificial tear drops are used during the recovery period and can be stopped once the corneal cells have re-grown after a few months. If your myopia regresses afterwards, an enhancement can be performed as long as there is sufficient corneal thickness left after the first laser treatment. Ectasia (weakness) of the cornea caused by excessive thinning during Lasik is very rare these days as new patient criteria have been set in place for its safe practice. People interested in Lasik but whose corneas are too thin or myopia too high are carefully screened out.

INSERTING A LENS IN THE EYE

Another option for your daughter is ICL surgery. The reason many doctors do not propose ICL first is because it is an invasive procedure. If an infection were to occur inside the eye, the consequences are more serious. The lenses used in this procedure are made of collagen and the plastic, polymer. The material is foldable, highly elastic and can be removed. It is FDA-approved for those aged 21 to 45. The lens is inserted behind the iris (the coloured part of the eye) and in front of the natural lens (above). ICL can correct extreme short-sightedness of up to -20.00 dioptres, and long-sightedness of up to +7.00 dioptres. This method does not involve reshaping the cornea and is associated with less post-operative dry-eye symptoms. For people with extremely dry eyes, ICL would be more suitable. When performed well, both vision correction methods have a very low rate of myopia regression. For ICL patients, the implants can be changed to those with a different power. It should be noted that while ICL is reversible, it would require another invasive surgical procedure to remove the implanted lenses. In rare instances, ICL surgery can lead to glaucoma and cataracts, due to the proximity of the implanted lenses to the patient’s iris and natural lens. If the lens implant is too big, there is a risk that the anterior chamber of the eye may become shallower, causing glaucoma by blocking the eye’s drainage angle internally. If the lens implant is too small, it may be displaced backwards, causing a cataract to form. It will be necessary to reverse the ICL procedure when such complications occur.

GOOD OUTCOMES

That said, the visual outcomes of both procedures have been predictable and extremely good. As Lasik is non-invasive, refractive surgeons would generally advise patients to do Lasik if they have normal corneal thickness and their myopia is not excessively high. If they are ineligible for Lasik, due to a thin cornea and high degree of myopia, then ICL implants are considered. Both procedures allow for cataract surgery in the future. It has been said that the removal of corneal tissue during Lasik may make it more difficult to accurately calculate the power of a lens implant for future cataract surgery. However, modern and advanced mathematical formulae have made calculations better than ever before. These days, the calculation of lens power for those who have had Lasik can be as accurate as for those who have not had the procedure. There is no best way to correct your daughter’s -8.00 dioptre vision. Several factors, such as age, refractive error and corneal thickness, will help the patient to make the optimal choice for himself. Your goal should be to consult an ophthalmologist who specialises in refractive surgery and who is able to provide all the different procedures available. You can then discuss the pros and cons of each method with the doctor before making a decision.

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THE STRAITS TIMES
JUNE 9 2011


Vision blocked by bright spots article

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Vision blocked by bright spots

Q) I am a 48-year-old woman. One day in January, when I was reading a book, I noticed that the words on the right side of the page were somehow blocked. I closed my eyes to clear the blocked spot of my vision. When my eyes were closed, I could “see” a bright patch towards my right side. There were colours surrounding the patch. The blocked spot cleared on its own after about 30 minutes. Is this an eye problem or has it something to do with my brain? Please advise.

A) It sounds like you have suffered an attack of ocular migraine.

This name can refer to two different conditions – one is usually not a cause for concern but the other might have more serious complications.

In some cases, ocular migraine describes a migraine aura – a symptom that usually precedes or accompanies a migraine – though it can sometimes occur without a headache.

Migraine auras are often visual, but may also include other sensations such as numbness.

You may see flashes of light, zigzagging patterns, blind spots or shimmering spots or stars. Such visual symptoms are fleeting and will affect both eyes. These symptoms can temporarily interfere with certain activities such as reading or driving.

An ocular migraine can be produced by the body’s neurological responses to certain triggers, such as hormonal changes, flashing lights or chemicals in foods or medications, causing changes to take place in the blood flow to the area of the brain responsible for vision (visual cortex or occipital lobe). This occurs most frequently in pregnant women and to people experiencing heavy stress.

Generally, ocular migraines are considered harmless. They are usually painless, cause no permanent visual or brain damage and do not require treatment. Still, always consult your eye doctor when you have unusual vision symptoms, because it is possible that you may have another condition requiring treatment, such as a detached retina, which should be checked immediately.

If your condition becomes chronic, you should consult a specialist for long-term management as there are many options to treat ocular migraines.

Sometimes, an ocular migraine is used as a synonym for another condition called retinal migraine.

A retinal migraine is a rare retinal condition which is caused by an infarct (an area of tissue death due to lack of oxygen) or vasospasm (a spasm of blood vessels that restricts blood flow and can lead to tissue death) in the affected eye. It is associated with repeated bouts of fleeting, diminished vision or temporary blindness. This may precede or accompany a headache.

Unlike a migraine aura affecting vision, a retinal migraine will affect only one eye and not both. Most often, the loss of vision in one eye is not related to migraine. It is generally caused by some other more serious condition and can be associated with some degree of permanent visual loss in recurrent cases. So, if you experience visual loss in only one eye, you should be examined by an eye specialist immediately.

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THE STRAITS TIMES
DECEMBER 22 2011

 


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Cataract correction by degrees

Q) I am 52 years old. In the last three years, the short-sightedness in my right eye has increased from 900 degrees to 1,300 degrees, but in my left eye, it has decreased from 700 degrees to 575 degrees. I saw a specialist who said the increasing severity of short-sightedness in my right eye is due to a cataract. He said my left eye also has a cataract but it is not as advanced. He recommended surgery to correct the vision in the right eye by 100 per cent and to insert a lens that corrects the short-sightedness in the left eye, so that I will no longer need spectacles. Alternatively, he could under-correct the vision in the right eye by around 800 degrees so that the difference in the level of short-sightedness between the two eyes is below 300 degrees, but I will still need to wear spectacles. Two of my friends who have undergone similar operations recommended that I correct my right eye by 100 per cent. Then I should wait for my left eye cataract to deteriorate and correct that by 100 per cent too, so that I will not need to wear spectacles. What should I do and what does 100 per cent correction mean?

A) For those who are around the age of 50, any significant increase or decrease in the level of short-sightedness is most likely due to the development of a cataract in the eye.

A cataract is formed when the usually clear lens of the eye becomes cloudy, usually from ageing. This hinders light from entering the eye and causes vision to become blurred over time.

The diagnosis of a cataract can be confirmed with a simple sight test and a clinical examination of the eyes by an ophthalmologist. The main aim of cataract surgery is to restore vision.

At the same time, cataract surgery is also an opportunity to correct or reduce pre-existing short-sightedness, long-sightedness, astigmatism and presbyopia. Presbyopia (known as lao hua in Chinese) refers to the inability to read books, newspapers and the computer screen, which everyone develops from the age of 40.

During cataract surgery, the cloudy lens is removed and replaced with a clear intraocular lens implant. High-precision biometry will be performed before surgery for an accurate calculation of intraocular lens implant power. Biometry is the measurement of an eye to calculate the necessary optical power of the lens implant. Based on your unique visual requirements, your surgeon and you can decide on a target surgical outcome for the eye. This can be achieved through detailed planning and selection of lens implant power. Normally, the degree of the lens implant is chosen to achieve clear distance vision (100 per cent correction), but it can also be chosen to balance the degree of the operated eye with that of the other eye by leaving a specific amount of short-sightedness (under-correction).

A 100 per cent correction will involve selecting a lens implant power which will negate all 1,300 degrees of short-sightedness in your right eye to achieve a post-operative outcome of zero (emmetropia). Your right eye will be able to see distant objects well without the need for glasses or a contact lens. However, the 575 degrees in your un-operated left eye will need correction with a soft contact lens until the day it undergoes surgery. Using spectacles where there is such a big difference in the refractive errors of two eyes will be intolerable to many individuals as they will feel “imbalanced” . Under-correction refers to selecting a lens implant power which will negate only a portion of the degree in your right eye (800 degrees as suggested by your surgeon), leaving residual short-sightedness (500 degrees) to balance with the 575 degrees of the left eye. This allows you the choices of either spectacles or contact lens for vision correction following surgery.

Many patients become intolerant of contact lenses by the age of 50 years as their eyes become increasingly dry with age, so you need to consider this: Are you able to tolerate contact lens well? If the answer is yes, you may go for 100 per cent correction of the right eye.

The second question to think about: Would you mind having to wear glasses after surgery? If you choose under-correction, you will have to continue wearing spectacles to correct short-sightedness.

In addition, at your age, you probably have presbyopia. After surgery, you will still need to manage presbyopia by wearing progressive lenses, bifocal lenses or a separate pair of reading glasses.

Alternatively, you can choose to have a multifocal lens implant, which provides for both distance and near focus. This significantly reduces dependence on reading glasses. Your ophthalmologist can assess your suitability for the implant.

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THE STRAITS TIMES
FEBRUARY 2 2012

 


Dry eyes need daily medication article

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Dry eyes need daily medication

Q) I am a 63-year-old woman. Is it safe to use Naphcon-A for my dry eyes once a day? I find using it to be more effective than using lubricating eye drops in easing the irritation in my eyes. I do not smoke cigarettes or wear contact lenses and I have no other health problems.

A) Dry eye syndrome is one of the most common reasons a patient turns up at an ophthalmologist’s clinic. The syndrome usually affects post-menopausal women, adults over the age of 60 and younger individuals who wear contact lenses for extended periods of time. Diseases such as blepharitis, which is the inflammation of the eyelash follicles, and meibomian gland dysfunction, which occurs when the oil-producing glands in the eyelids become blocked or inflamed, can also cause dry eyes. So can other diseases in which the immune system attacks the body, such as systemic lupus, rheumatoid arthritis, which affects the joints, and Sjogren’s syndrome, which curtails the production of tears and saliva. The symptoms of dry eyes are irritation, dryness, soreness, itchiness, a burning sensation, chronic redness, intermittent blurred vision and excessive tearing as a reflex to the dryness.

There is no complete cure for the disease. Rather, the management of the disease is more about achieving an acceptable level of eye comfort, which differs from patient to patient. Each eye doctor also seems to have his own preferred method of managing this ailment. When deciding which therapy to prescribe, an ophthalmologist would normally customise a management plan according to the cause of the disease, the severity of the symptoms and the lifestyle of the patient.

The treatment of dry eye syndrome may include one or a few of the following strategies:

Use artificial tears to maintain comfort

There are many formulations and brands of artificial tears available which can reduce dry eye symptoms to a manageable minimum. Preservative-free tears can be used as often as desired.

Lubricate the eye overnight

For more severe dry eyes, it is very helpful to use lubricant ointment or gel preparations just before going to sleep.

Use punctal plugs

Normally, tears from the eye drain through a tiny tear duct (puncta), which is situated at the nasal corner of each eyelid, into the nasal passages. Placing either a temporary plug made of collagen or a permanent plug made of silicone in the lower lid punctum can reduce the rate of drainage of tears from the eye, making any natural or artificial tear last longer on the ocular surface.

Practise good eyelid hygiene

This is important for the maintenance of a healthy lipid tear layer. The symptoms of dry eyes commonly co-exist with meibomian gland dysfunction. Commercially available products can help cleanse the skin around the eyelashes and reduce the amount of bacteria growing there. They include eyelid cleansing pads which may be helpful in combination with warm eyelid compresses and eyelid massage.

Take omega-3 fatty acid supplements

Beneficial effects have been achieved when such supplements have been used as an adjunctive therapy.

Get prescription medication

If you have severe dry eyes, you may require prescription medication such as topical steroids, topical non-steroidal anti-inflammatory drugs and immune-modulating compounds. Their use requires careful monitoring by an ophthalmologist. Naphcon-A is a topical eye medication which is a combination of an antihistamine and a decongestant. It is used for the relief of eye irritation and/or nasal congestion (the blockage of nasal passages due to swollen membranes), or for the treatment of allergic or inflammatory ocular conditions. It is not normally used as a long-term solution for dry eye syndrome. If you find that it is the most effective medication among all else mentioned above, it may be that you are suffering from an allergic eye disease. Hence, you may want to consult an ophthalmologist for an opinion.

 


How to select the right procedure to correct your vision

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LASIK, epiLASIK and ICL

How to select the right procedure to correct your vision.

There is a range or different surgical solutions to treat your short-sightedness, astigmatism, long-sightedness or presbyopia which Is the age-related loss of ability to focus on near objects.

Bladeless LASIK

A well-known method, bladeless LASIK is a painless ten minute procedure that corrects your eyes’ power by re-shaping the cornea. lt is a non-Invasive procedure which is considerably affordable among other refractive eye surgery methods. Although no lifetime follow-up is needed and clear eyesight resumes within 24 hours of surgery, temporary’ dry eyes and haloes effect can be expected

For two months post-op. LASIK Is approved by the Food and Drug Association (FDA)for people 18 years and older, with no upper age limit. This procedure is unsuitable for people with cataracts.

epiLASIK and LASEK

Also suitable for people aged 18 and about epiLASIK and LASEK are alternatives to LASIK and suitable for people with thin corneas, epiLASIK uses a blunt blade while LASEK is bladeless. They remove less tissue but require a longer visual recovery time of one to two weeks. Discomfort, swelling and tearing in the eyes can be expected for three days, as well as temporary dry eyes and haloes occur for two months postop.

Implantable Contact Lens(ICL)

An invasive method that costs more, the ICL procedure implants a collamer lens into the eye. It is suitable for people with veil, high spectacle degrees or very thin corneas, Clear vision resumes within 24 hours and Lifetime follow-up is recommended until the lens is removed because of The rare chance of complications like glaucoma and cataracts. Temporary dry eyes and haloes occur to a lesser extent post-op. The FDA-approved age for ICL is 21 to 45 years

Intra-ocular Lens Implant

Intra-ocular Lens Implant is appropriate if you are suffering from presbyopia or cataracts, as you will not be suited for the aforementioned refractive eye surgery procedures. Unlike ICL, this procedure involves the replacement of the natural lens in your eye with the intra-ocular lens implant_ ‘Do take note that you have the option of the bladeless femtosecond laser cataract surgery if you are suffering from cataract.

DR NATASHA LIM EYE CENTRE PRESENTS


Eye design article

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EYE DESIGN

Fancy having clear vision without the trouble of putting on contact lenses or spectacles? Get cleared up with Laser Vision Correction

Ophthalmologist Dr Natasha Lim, medical director of Dr Natasha Lim Eye Centre, shares her wealth of knowledge on Laser Vision Correction (LASIK) and how this treatment brings comfort and ease to the bespectacled. Educated at the University of Nottingham Medical School in the United Kingdom, Dr Lim underwent a residency training programme in Ophthalmology in Central London before undergoing advanced surgical training at Moorfields Eye Hospital in London, one of the most renowned eye centres in the world.

In layman terms, what exactly does Laser Vision Correction do to our eyes?

Laser Vision Correction (LVC) uses a beam of light from an excimer laser to reshape the front surface (cornea) of the eye, treating short-sightedness, long-sightedness, presbyopia and astigmatism, enabling complete freedom from glasses and contact lenses. Over 22 million laser eye surgery procedures have been carried out worldwide helping to improve people’s quality of life.

How might one determine if he or she is the right candidate for LVC?

LVC is not for everyone. One should see an eye surgeon who specialises in this surgery for a complete and thorough eye examination. There are also certain issues one should consider before deciding whether or not to undergo the surgery, such as am I willing to accept a low but real risk of surgical complications, has my vision been stable long enough to have LASIK, and are there any health conditions that can make one a poor surgical candidate.

What is the recommended age group for LASIK?

Patients under age 18 are rarely stable enough for LASIK, and older patients may begin to develop cataracts or other eye health issues that preclude them from undergoing LASIK. Again, the best way to determine suitability for surgery is to have a complete eye examination.

How is iLASIK different from other similar procedures on the market?

The latest iLASIK platform has the iDesign machine which uses wavefront-guided technology to measure and correct the unique imperfections of each eye 24 times more precisely than conventional methods thereby increasing the potential for better vision than is possible with glasses or contact lenses. It was iLASIK technology that enabled organisations with the highest safety and visual standards including the US military and NASA to approve LASIK surgery for their servicemen in 2007.

What are the risks of LASIK, or iLASIK?

No surgery is without risks. It is very rare for complications from this procedure to cause permanent or significant visual problems. Any complication can usually be resolved through laser re-treatment. Selecting the right eye surgeon is the most important thing you can do to decrease your risks. If unexpected problems should develop with surgery, a good surgeon should be able to work closely with you to resolve it.

Enhance Your Eyelid Contours

Many people become motivated to start wearing eye makeup after LASIK and desire to have bigger looking eyes, which can be achieved with double eyelid surgery.

• Asian blepharoplasty—also known as double eyelid surgery—reshapes the upper eyelid in Asian patients, creating an upper eyelid skin crease to widen the aperture of the eye and achieve a more “westernised” look simultaneously.
• With regard to the recovery period, after a full incision technique surgery, it normally takes one to two weeks for the swelling to subside. Minimally invasive procedure normally takes five to seven days for limited swelling and redness to subside.
• Possible risks to the procedure are asymmetry and infection at the site of surgery. These complications are correctable and treatable should they occur. Chances of complications are low. Scarring does not usually pose a problem as it would be along the skin crease should it occur and hence would be concealed.

Style» Lasik And Eye-care
MT PAPER TUESDAY JANUARY 22 2013

 


On the wavefront of Lasik article

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On the ‘wavefront’ of Lasik

SINGAPORE – Tired of waking up to blurred vision, formerly-bespectacled Ting Tieh Siong took the plunge last month by going for a Lasik operation.

Now, the 31-year-old sales manager is loving his crystal-clear vision, or what he calls “Superman” vision.

He said: “It was really troublesome to wear glasses when I went jogging or swimming. It feels great to have clear vision from the moment I open my eyes.”

After undergoing customised Lasik surgery, he now has an eagle-eyed vision of 6/3. This means that his new vision is better than that of 6/6, the benchmark for perfect vision.

His ophthalmologist, Dr Natasha Lim, 42, revealed that this was made possible with personalised laser eye surgery called wavefront-guided Lasik.

Here’s how it works: She creates a 3-D map of the eye using a high-resolution eye scanner called iDesign. During surgery, the scan is superimposed onto the cornea to serve as a guide for the laser treatment.

The experienced ophthalmologist, who runs Dr Natasha Lim Eye Centre at Mount Elizabeth Novena Specialist Center, said: “Without the map created by iDesign, Lasik can treat the eye only for short-sightedness and astigmatism.

“This machine goes one step further to detect optical disturbances inside the eye.”

These disturbances usually affect one’s vision at night, and include glares, halos and starbursts of light. For instance, a person may see halos surrounding a traffic light.

Dr Lim added that the new eye scanner at her clinic has a resolution five times higher than that of its predecessor.

This means that the new scanner can pick up even more optical disturbances within an eye which the surgeon can zap away during surgery.

Those with corneas deemed too thin for Lasik can now undergo it with this method, said Dr Lim.

She added: “Using the older Lasik technique, in which the corneal flap is cut with a blade, cornea flaps are cut significantly thicker, which means the patient ends up losing more tissue from the operation.”

The Femtosecond Laser technique used by Dr Lim cuts a super-thin flap in the cornea.

She said: “The more cornea thickness is left behind after your Lasik operation, the stronger the long-term biomechanical stability of the eye.”

Also, the laser cuts a super- thin flap in only 10 to 12 seconds, with the cornea receiving much less energy.

Hence, there is very little inflammation post-op and recovery of vision is fast.

Dr Lim said: “Many patients report clear vision within half an hour of the operation, which tends to get better and better every hour.”

Though the operation can be performed in 10 minutes for each eye, the rigorous pre-assesment done by Dr Lim and her team can take up to three hours.

The assessment includes measuring the exact geometry of the corneas as well as their thickness, and testing the size of the pupils to ensure that surgery will not cause problems of glare and halos at night.

Dr Lim said: “A patient’s safety is of utmost importance to me. I personally spend a lot of time checking his suitability to undergo this procedure safely.”