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: