Tuesday, February 2, 2016

A barber rant and Chinese myths about surgery

Yesterday I went to a budget hair snipper for the regulation pre- Chinese New Year hair cut.

I was admonished by a young (?early twenties) guy with dyed blond hair in a fancy do that my oily skin was causing my thinning vertex, because "the oil was clogging the hair follicles". This isn't the first time I have come across such 'advice'. It seems every time I go to a place with a younger generation of hair dressers, I get this same advice. There seems to be an extremely knowledgeable hair dressing lecturer doing the rounds in Singapore.

Because I have had this advice a number of times before, which is just about as much as I could handle, I asked him if he had ever been to medical school. I am grateful he didn't give me a bald patch at the time. But I am going to an Indian barber the next time.

I'm glad my hair did not turn out like this...

Which kind of brings me to a couple of common questions originating from Chinese myths and traditions that we commonly get asked by patients who are going for surgery.

Number 1: Can you eat seafood after cataract surgery?
My answer-Yes, and do enjoy yourself to your hearts' content with prawn, crabs, lobsters, etc

TCM regards some seafood as 'fa wu' or stimulating, and these (which include cured fish and shellfish) may cause inflammation according to traditional Chinese beliefs.

It's possible that shellfish allergies are fairly common, and along the way they became associated with causing itching-as what commonly happens with any healing wound. It is also possible that undercooked shellfish such as clams and cockles commonly cause food poisoning, since they often concentrate toxins and bacteria by dint of their lifestyle as filter feeders.

However, well cooked shellfish are in fact nutritious and rich in proteins and minerals such as iodine and zinc. And as long as a person is not allergic to them, they are a perfectly good food to eat whether surgery has been done recently or not.

Number 2: Will eating things with soya sauce cause the surgical wound to turn black?
My answer-No, so don't worry, go ahead and make your food a little more tasty with that magic sauce.

Any wound develops inflammation, which is part of the healing process. In the active inflammatory phase, the wound is pink, and as it heals, the pinkness goes darker. Eventually, after a period lasting weeks to months, the dark colour fades. This darkening is a normal phenomenon and is called 'post-inflammatory pigmentation'. We see it with other types of inflammation such as pimples or a scraped knee, as well. So no, it is not due to the black colour of soya sauce. Otherwise we are also going to have to ban coffee and marmite/vegemite-I think these are going to be an even harder sells than prohibiting soya sauce!

Do you know any other traditional myths surrounding surgery and post-operative care? Do let me know!

Wednesday, November 18, 2015

What is it like having premium IOLs that correct for near vision after cataract surgery?

Some time ago I was asked this question on the Quora website:
What is it like having premium IOL's that correct for near vision after cataract surgery?

A very relevant question, given that nowadays there are so many lens options to choose from and also different approaches to avoid reading glasses. Here is my answer:

There are several different types of IOLs that give multifocality and good near vision as well as distance vision. I will base my answer on the most commonly used lenses-the diffractive multifocal lenses like the Alcon Restor, the Tecnis Multifocal and the Zeiss trifocal lenses.

The Alcon Restor lens (above), and the AT LISA tri (below) are examples of bifocal and trifocal lens implants, respectively.

These diffractive multifocal lenses have rings etched onto either their front or back surfaces, which split/diffract incoming light rays into two foci. Some newer ones can even split the light into 3 foci. This fact gives rise to several implications.

1. Vision will be clear mainly at 2 (or sometimes 3) distances. For the older +4 Restor and the Tecnis multifocal, the near focus is at about 1 foot. So reading material has to be held quite close.

If it is held further away (say at 3 feet or so-intermediate distance), then it is not so clear anymore. 

Then things much farther away, say 15-20 feet away, start to become pretty clear again. (See the figure below-only the AT LISA tri is clear at intermediate distance)

Note: This is only the case if the surgeon has been very accurate in calculating the lens power/biometry.

Simulated clarity of images at various distances with different multifocal lens implants. The top 3 are bifocals, and the bottom one is a trifocal. Only the trifocal gives pretty good intermediate vision-but at some cost in terms of contrast when compared with the Alcon SV25T0 and AMO ZKB00. (From IOVS 2015;56:3970)

2. Because of the light splitting, there is a drop in contrast compared with a monofocal lens. Patients with multifocal lenses tend to be more sensitive to low light conditions-ie when it starts to get a little dark, they start to feel the drop in vision faster than patients with monofocal lenses. A person with a monofocal lens and reading glasses could read in dimmer conditions than a person with a multifocal lens.

3. The rings on the IOL give rings of light (halos) around light sources. This can be an issue when driving at night because of the halos around car headlamps. Having said this, many patients get used to the halos and do not notice it as much after a time.

Simulated halos around lights from a mutifocal lens

The above of course does not completely apply to the Crystalens or the Oculentis MPlus. The Crystalens is an accommodative lens, which gives somewhat unpredictable results-some patients don't get any near effect at all. 

The MPlus (available in Europe/Asia) has a wedged shaped section on the lens to focus for near. Point 1 above applies to this lens as well. However, although this lens does not give rings around lights, it can still cause 'halos' of a different shape-it is more like a smearing effect in one direction. Occasionally if a patient's pupil is small and not aligned with the lens, the patient may only have a far focus or a near focus and not both.

Last but not least, there is the Symfony lens which I covered in my last post. As mentioned, this is an 'in between' lens, ie in between a monofocal and a multifocal. It has no intermediate vision problems, and less halos than the usual multifocals, but does not give quite as good very near vision.

Currently, I offer patients a choice between a monofocal, an in between lens like the Symfony, and a full fledged trifocal like the AT LISA tri. I believe there is little to no benefit to be gained from using older bifocals such as the Restor and Tecnis Multifocal currently. Exactly which of those 3 choices gets implanted comes after a careful discussion with my patient regarding the pros and cons of each option. (So that we get big smiles all round afterwards!)

Tuesday, October 27, 2015

My experience implanting the Symfony lens this past year

What's a Symfony? Or Symphony? A symphony is actually an extended musical composition written for a variety of musical instruments, usually in an orchestra. Google Symfony and you get results pointing you to free software for a 'web application framework'.

But of course, I'll be talking about a lens implant for cataract surgery. The Symfony lens is a type of lens to allow for a greater range of clear vision after cataract surgery. Normal lens implants (monofocal) allow good vision at 1 particular distance, either near, or far, but not both. Multifocal lens implants can give good vision at 2 or 3 distances, but have not been very popular due to certain side effects like halos.

The Symfony is kind of an in-between lens-ie in between monofocal lenses and conventional multifocal lenses.

Time really flies-it's almost a year now since I started using this lens for patients. So, how's it like? In general, I would say it lives up to expectations.

In this past year, I have implanted the Symfony in different sorts of situations-including for people who already have had cataract surgery with a normal monofocal lens in the other eye.

Distance vision
With correctly done biometry, aiming for close to emmetropia (close to 0 spectacle power), the Symfony gives very good distance vision and patients were universally happy with this. 94% of my patients saw 6/6 or 6/7.5 without glasses after surgery.

The remainder had small amounts of spectacle power and in one patient whose best corrected was 6/12p, she had prior retinal detachment surgery.

What about near vision?
All Symfony lens patients could see N8 type comfortably without glasses, which is this smalland 92% could see N6 comfortably without glasses, which is this small

Although perhaps this near vision is 'less good' than the traditional bifocal or trifocal multifocal lenses, I would say this is adequate for most people most of the time...

What about halos?
Some patients, when asked, did describe mild halos around lights at night (such as car headlamps or traffic lights) but were not troubled by these halos. One patient even called it pretty!

The distinguishing feature of Symfony related halos (mentioned by 18% of my patients) seemed to be that they were quite mild/light, and patients were able to see through the halos.

Personal thoughts
There is still no perfect solution for presbyopia as yet. However, I think for myself, the Tecnis Symfony is one of the best compromises out there at the moment.

1. Minimal halos

2. Minimal drop in contrast-patients with a monofocal in one eye and a Symfony in the other are not troubled by the difference in contrast

3. Optical behaviour and patient experience mimics an early stage of presbyopia-there is no sudden fall off in intermediate vision, and vision slowly gets more blurry when things are brought closer. The effect of the Symfony has been likened to vision of somebody in their early forties.

With some of the other multifocals, there is really no equivalent in real life-the feeling could be somewhat unnatural and it could take some time to get used to.

But the Symfony is not perfect.

The chief one is as above-it is like early presbyopia. So, for people who don't mind more halos and who also don't mind a greater drop in contrast, but who would like clearer vision very close up, then a trifocal lens implant like the AT LISA tri or Finevision IOL would be good options. At the end of the day, the adage 'there is no free lunch' still holds true!

Tuesday, October 20, 2015

Learning phacoemulsification cataract surgery

Performing phacoemulsification cataract surgery is nowadays the quintessential eye operation-the one that most people think about when referring to eye doctors. To recap, this operation removes the hazy natural lens of the eye, and replaces it with a new, perfectly clear lens implant.

What's doing the surgery like?
It is a bit like playing an organ (or driving a car with manual transmission), you need both hands and both legs-how so?

Left foot:
Operating microscope (focus and zoom adjustments)
Right foot:
Phacoemulsification machine pedal (activating vacuum/aspiration and ultrasound power)

Left hand:
Second instrument for manipulating cataract
Right hand:
Phacoemulsification handpiece

So, it is a bit of a ballet, with coordination between the 2 hands and  the right leg the most important part. Like learning how to drive a car, after a while (for experienced surgeons)
1. Most of the routine parts become automatic
2. We anticipate problems that may occur
3. We consciously and subconciously set safety limits on what we do
4. We tweak our technique according to the type and hardness of cataract we are facing

Phacoemulsification is also done entirely while looking through a microscope. That takes a little time to get used to. Hand-eye coordination is particularly important, because there is much less tactile feedback when dealing with tiny things. I like to think that computer gaming in my younger days helped in this regard!

Wet lab training

A 'wet lab', you say? You mean there are wet ones and dry ones?

A wet lab in the context of surgical training involves the teaching of techniques using wet material-ie animal eyes and similar such biological tissue. We did some training for phacoemulsification on pig's eyes and also stitched pig eyelids for practice in our day.

However, animal eyes are very different from human eyes. In fact, it is usually more difficult to accomplish certain techniques with such eyes than in real life, and I was never very fond of wet labs. Still, the experience of doing things while looking through the microscope was quite useful.

Milestone: first phaco

It actually didn't take me very long before I performed my first whole cataract surgery. Besides wet labs, cataract surgery was taught (and it still is quite similar today I think) by letting the training surgeon perform some steps of the procedure at the beginning. For some trainers, this might be what are considered the easier steps first, followed by the more technically demanding ones. I started out under Mr Fearnley at Northampton doing the incision, and by the end of the year, just before Christmas 1999, I had performed my first full phacoemulsification cataract operation and lens implant under Mr Baranyovits. It was a huge milestone, finally I got the feeling that I could actually cut it as an eye surgeon!

As a trainee, there is always a sinking feeling when the supervisor says-"time for me to take over...". However, although you had to stop, it was then a great opportunity to see at first hand different techniques used to rescue the particular situation at hand, whether it was a posterior capsule rupture or zonular dialysis. The best supervisors will give a debrief and perhaps go over the surgical video when everything's done and dusted. This is a bit like reviewing the black box after a crash, the difference being that great supervisors sometimes salvage situations so well that post-operatively, the patient is none the wiser.

I went through a period when I would read anything I could find on the topic. I read Barry Seibel's 'Phacodynamics' practically cover to cover. I would visualise and imagine different techniques and scenarios in my head. I would review many surgical videos, whether they were straightforward or complicated cases. And slowly, bit by bit, doing this operation became second nature to me.

Live surgery

Every year, there are 4-5 major ophthalmic conferences where live surgery takes place. A live feed is installed from an operating theatre to the conference hall, and we get to see well known surgeons performing surgery with live commentary from a panel of experts at the conference hall. Which is not so different from listening to Thierry Henry weighing in on the Arsenal team on match day...!

I often attend these sessions, where sometimes manufacturers will showcase new surgical equipment or new lens implants. Occasionally we see new surgical techniques, but often the cases are fairly standard cataracts. Occasionally we see unplanned 'highlights' (the whole conference hall becomes deathly quiet...), and while I don't think anybody wishes for these complications, sometimes we learn more when things don't go so smoothly, rather than the other way around.


Nowadays there are videos of everything on the internet, including cataract surgery videos! While I don't think I have learnt anything much personally from these videos, I could see how they might be useful to younger surgeons in an earlier phase of their training. It is always worthwhile to take a look and think of the things the other surgeon is doing well, and also on what could be improved.

I posted this video to share some tips to deal with difficult dense white cataracts (Note: graphic video of eye surgery):

To sum up

As in most things in life, the best practitioners of a procedure make it look simple. The best practitioners of a procedure also deal with all types of cataracts and potential complications of the procedure well. Even though nowadays cataract surgery can be done within 20 minutes or less for each eye, it takes a fair amount of time and training to get to a stage where we are both slick and safe at it. For me, it is a great privilege to have this opportunity to help so many people, and it's a very rewarding one at that!

Saturday, October 10, 2015

Medical conditions which show up in the eye

I am often asked by patients: Can you see if I have other medical problems just by looking in the eye?

Actually, yes, sometimes.

Let's start with vision. What we can see at the sides while gazing straight ahead is called our visual field. Normally we can see things about 120 degrees horizontally out in front of us, while vertically the visual field extends about 30-40 degrees.

When conditions affect the nerve of the eye, the visual field is often affected. The pattern of visual field loss can offer vital clues as to the underlying problem. For example, if the sides are affected and this loss stops abruptly at the midline, there might be a growth pressing on the nerve of the eye.


Diabetes is a condition which affects most if not all parts of the eye if it is not controlled well. The most well known problems have to do with retinal bleeding, which starts off with small spots of blood and fluid/cholesterol leaking into the retina, which is the thin film at the back of the eye. Later on, if it becomes more severe, new blood vessels can grow that cause more severe bleeding and scarring.

Moderate disease, with small spots of blood and some leakage of fluid with cholesterol (yellowish spots) 
Severe diabetic retinal disease with scarring of the retina
The most important factor in avoiding eye disease among diabetics is controlling the level of blood sugar. Generally, the better the blood sugar is controlled, the less the risk of geting eye disease, or of the eye disease getting worse.

High blood pressure

High blood pressure affects blood vessels throughout the body, but this is not usually obvious until it causes severe changes such as heart disease. In the eye, the small blood vessels are usually examined with microscopes, and small changes may be picked up earlier.

When the blood pressure is high for a long time, the arteries get thicker and can press on the veins. Sometimes this causes the vein to be blocked, which can lead to back pressure, bleeding in the retina, or swelling of the retina. After a long time the blocked blood vessel may turn white (see below).

High cholesterol levels

High cholesterol levels have been associated with a greyish white ring at the side (periphery) of the cornea.
Not everybody with this ring (called arcus senilis) has high cholesterol levels, but its presence suggests that one should get a blood test to make sure the level is not high.

Narrowing of the neck arteries with cholesterol/calcium deposits

Cholesterol deposits in the neck arteries may throw off little pieces, which can travel to the brain to cause strokes, or to the blood vessels in the eye and block them.
Small pieces of cholesterol blocking a blood vessel in the eye. From Stanford University http://stanfordmedicine25.stanford.edu/the25/fundoscopic.html 

High pressure inside the head

High pressures within the head may be due to a variety of conditions, such as bleeding from injury, tumour, or blockage of fluid (CSF) flow. The high pressure causes swelling of the end of the optic nerve, which is visible when the eye doctor looks inside the eye. Commonly, the high pressure also causes headaches, which may be associated with nausea and vomiting. On the other hand, most headaches are caused by other reasons, like tension or migraines.

So, although we cannot actually peer into the soul by looking in the eyes, there is still plenty that we can tell by examining this part of our body, that we would otherwise have no clue about!

P/S: Check out this nicely made video about the same topic at National Geographic:

Tuesday, September 15, 2015

What type of lens implant should I choose for my cataract surgery?

Taking a quick look through a few eye care forums often turns this up as a commonly asked question, and one that garners quite a number of readers. This is not surprising, since over the years, more and more types of lenses with different pros and cons have become available. To recap, cataract surgery involves removing the hazy natural lens of the eye (called a cataract), and replacing it with a new lens implant.

Some of the currently available lenses: Tecnis Symfony (left), Acrysof  Toric monofocal (middle), and Zeiss Trifocal (right)

With cataract surgery nowadays, it is not so much the phacoemulsification technology or whether laser is used that affects the outcome. Rather, the outcome is determined by how accurately your doctor can calculate the necessary lens power, and what kind of lens is implanted into the eye. The available implants include 'monofocal' lenses (good vision at one distance), monofocal toric lenses (monofocal but with added feature to reduce astigmatism), and multifocal lenses (of which Extended Depth of Focus (EDOF) lenses can be considered a subset of - these provide clear vision at more than one distance).

Important questions to answer:

1. Do I value distance vision without glasses more, or near vision without glasses more?

2. Would I mind wearing glasses of any kind, including reading glasses?

3. Would monovision (one eye set for clear distance vision without glasses, the other for near) be a suitable option? Any prior experience with monovision or any chance of simulating it?

4. Would I mind intermittent visual disturbances such as halos around lights?

Simulated halo around a light, as seen through a multifocal lens

In some clinics, a questionnaire including these questions is filled in by patients prior to their surgery, to help in deciding on the type of lens for them. Of course, there is the final issue of cost, with multifocal and especially multifocal toric lenses commanding a premium.

Let's talk about some case scenarios:

1. You are very used to wearing glasses, and would actually like to wear them after surgery.
If you were shortsighted (myopic) before cataract surgery, and you habitually took your glasses off to read, then you would be good with monofocal lens implants but aiming to leave behind -1.50 to -2.00D of shortsightedness, in both eyes. Conversely, if you were hyperopic, I find that most patients like emmetropia (good distance vision without glasses), and then wear reading glasses for near visual work.

2. You had experience of monovision before, and liked it.
This could have been achieved naturally, or via glasses/contact lenses/LASIK. In this situation, it would be good to replicate it via cataract surgery.

3.You hate wearing glasses of any kind, and are concerned that monovision might not suit you or have tried it before and it does not suit you. 
In this case, you could consider the Extended Depth of Focus (EDOF) lenses, or the trifocal lenses. These lenses work quite predictably but also can cause some visual disturbances such as halos/rings around lights especially in the dark. Of these varieties, the EDOF lenses such as the Tecnis Symfony tend to cause the least disturbance ie least halos and least reduction in contrast.

If the benefit of seeing clearly at most distances with both eyes outweighs the possibility of some halos, then these lenses can be considered.

Generally, I would continue to avoid 'accommodating' lenses such as the Crystalens, and other multifocal designs such as the Oculentis Mplus range of lenses.

Hopefully, this post gives an idea of the thought processes that go into choosing a lens implant for cataract surgery. There is no one 'best lens' for everybody, and hopefully in the future there will be even better technology that can be applicable to more poeple with fewer side effects. Questions? Please feel free to post comments below.

Tuesday, August 4, 2015

Eyelid cysts a.k.a. chalazia or styes

Most of the time, cysts of the eyelids or ‘bak chiam’ (in Hokkien) are caused by blockages of the oil glands inside the eyelids. When the openings of these glands are blocked, the oil produced by the gland cannot be released, and it builds up to form a lump in the eyelid.
The white dots are blocked oil gland openings
Oil collects inside the blocked gland, causing a lump to form

Commonly, it feels like a little pea, which can be painful if it gets infected. These cysts are also called ‘chalazion’, and they are very common. They can be associated with inflammation of the eyelids called ‘blepharitis’. Normally, most chalazia are not serious and many do go away on their own with time. Big ones near the middle of the upper eyelid can cause blurring of vision by pressing on the cornea/window of the eyeball.

Problems with these cysts arise especially when they do not go away after a long time, or if they keep coming back. Big cysts that do not resolve on their own are easily treated with a 5 minute office procedure to drain the oil from the blocked oil gland.

Cysts usually happen individually, and then disappear for long periods of time. On the other hand, a smaller proportion of people get cysts that go away and then come back, often in another eyelid or even on the other side. Recurrent cysts are usually associated with ongoing eyelid inflammation. For many people, hot compresses at night followed by eyelid cleaning (perhaps with products such as Lid Care/Blephagel) are helpful in reducing the chances of recurrence.

Very stubborn cases may be related to changes in the eyelid oil to a very thicky waxy material which blocks the channels of the glands. It is thought that these changes are related to the type of bacteria living on the skin of that person, which can also change the normal oil to other irritating substances.

Treating chalazia

The simplest measure recommended is hot compresses, with which we hope to make the oil more liquid and to flow out better.

It has been found that long courses of certain antibiotics from 1 month to several months help to resolve many of these blepharitis cases. Besides their antibacterial action, antibiotics in the tetracycline class also have anti-inflammatory properties. Besides antibiotics, taking Omega 3 oils in the diet or via supplements also helps to reduce the thickness of the eyelid oils and to reduce inflammation in the body.

Oil in some of the glands has turned into a thick material like toothpaste. In some other glands, the oil remains liquid and comes out as little droplets.
Recently, it has also been reported that some people have an overgrowth of skin mites in the eyelids. An article in the American Journal of Ophthalmology (Am J Ophthalmol. 2014 Feb;157(2):342-348) found that more patients with chalazia had these mites, and that patients found to have these mites had a higher chance of cyst recurrence. I routinely check for the presence of these mites in patients with inflammatory eyelid problems, and start treatment against them if necessary.

Pulling gently on the eyelashes causes the white tails of the mites to poke out. They can be teased out onto the eyelid surface and then scooped up with forceps.

One mite having a stroll across the microscope slide...

If despite simple measures the cysts persist, then a simple incision and drainage procedure can be performed in clinic. This usually take 5 minutes or less, after which the eye is padded for 2-3 hours.

Can these cysts be anything more dangerous? Very rarely, yes. There is a rare oil gland tumour that can present like a cyst. If a cyst keeps recurring in the same place, and especially if it is gradually getting bigger or associated with adjacent loss of eyelashes, the doctor should consider taking a specimen and sending it to the laboratory for further examination. But this is a rare condition and is unlikely if the recurrent cysts are happening in different places.

To summarise, do consult an eye specialist, as sometimes prescription medicines like antibiotics or other treatments may help. Dietary changes like taking more Omega 3 oils also would be good, and in the meantime continue with hot compresses and keeping the eyelids clean.