In Contact - July 2006
Who Needs DNA?
I recently examined a patient who?d just flown in from Japan. He was wearing custom-made soft lenses fitted at an eye hospital over there. Both lenses showed fairly dramatic inferior decentration and appeared to be high-plus or aphakic lenses. He explained that he suffered from congenital aphakia and glaucoma and was under the care of various specialists. A family history of congenital cataracts and glaucoma was also elicited.
Examination revealed an IOL in the left eye, which was however still hyperopic, with aphakia in the right. Pupils were also irregular and somewhat dilated.
We didn't have much time to refit and complete aftercare before he was due to return to Japan so got right into it?
After analysing his corneal topography I noted in the first instance extremely flat corneas [around 36.00D] with low eccentricity.
A tentative diagnosis of ?cornea plana? seemed reasonable.
I trialed and succeeded in refitting him into 9.0/14.2/+4.50D 1-Day Acuvue on the left eye for near vision in a monovision setup. He obtained 0.50M acuity @ 36cm. With full over-refraction we obtained 6/9 in the distance.
For the right I had a custom Proclear manufactured in 9.3/14.0/+20.00D and we obtained 6/9 for distance. A change from ReNu to AOSEPT also resulted in improved patient satisfaction.
Both lenses fitted and centred much better. He obtained improved vision and comfort with the added bonus of less flare as a result of the larger optic zone and centred optics. Movement was satisfactory.
He asked me how ?bad? his eyes were.
As they do.
To illustrate I said that rarely in the past 25 years have I ever seen such naturally flat corneas. [As I write this I had a surgically-induced post RK cornea of 32.00D to sort out]
I also mentioned that often these cases come in ?clusters? and that funnily enough I had recently seen a female patient, originally fitted in Hamilton, with almost identical measurements.
The file was still lying around on my desk awaiting completion.
I told him that their eyes were so similar that they could have been brother and sister.
I did however say that she had a different surname. [Under the privacy act I could not reveal her name.] He then mentioned he had a sister whose married name was xxxx and that as far as he knew she had similar problems.
Lo and behold it turned out it was indeed his sister!
Amazing.
One comes in from Japan, the other referred from Hamilton and their ocular similarity made me link them genetically. I have also subsequently seen their mother.
Mother and daughter both wear RGPs and the sister?s Rx has achieved my all time maximum record for the flattest, highest plus RGP I have ever designed and fitted:
9.72mm BC/ F= +32.75D / custom tetracurve / 9.8 Diameter in 125Dk Optimum Extreme, with DAC front and back blended lenticular and a high minus carrier.
Their lenses (of similar design) with increased minus carrier and increased optic zone have led to significantly better centration. So good in fact I was rather pleased with our efforts.
My compliments to CLC for these DAC-lathed beauties.
A Fake?
No, I'm not referring to Prime Minister Helen Clark?s faked painting.
I'm continuing along the aphake theme.
Imagine for a minute though if I'd ever provided the NZ authorities, ODO Board or Helen?s cronies at the MoH with faked documents?
I'd be instantly ?struck off?, put on a slow boat to China and checked into a Chinese organ ?donor? institute.
I cut my teeth fitting aphakes. Way back then in the last century, IOLs were just coming on-stream. They were pretty rough and ready by today?s no-needle, suture-free, phaco-emulsified foldable versions.
In those days getting the often 80 to 100 year old patients fitted, instructed and managed was never easy. Our technology was limited to sub-15Dk RGPs [usually 8 or 12 Dk]. They were all made on manual lathes. None of the fancy surfaces we have today.
Amazingly we mostly obtained fantastic results.
I still have a few aphakes that I fit and manage but thankfully not many.
I can?t say I miss them.
I remain in awe of some of the amazing results the surgeons I deal with achieve with modern cataract surgery. To fully appreciate it one should sit in with your favourite surgeon and observe the skill and precision - through the ?teaching? operating microscope - just inches from the patient.
Last time I sat in I was sweating more than the surgeon and the mildly tranquilised but conscious patient.
They?re pretty cool customers, these surgeons!
Full Credit.
Biofilms
One issue I've been planning to report on was the role of biofilms in infection. I had to put this issue on the backburner due to more pressing issues like fusarium keratitis and the MoistureLoc recall. It now seems they are linked, in a rather unusual way, so let?s get into it.
As a kid we used to go to the ?bio? and see a film. These bio films are different.
I've long had an interest in biofilms in contact lens care: Especially as far as gunky, old contact-lens storage cases go.
It is theorised that a biofilm, - literally a slime-like coating, similar in nature to fouling on a boat?s hull ? creates an ?impermeable? film within and ?under? which nasty microbes [like acanthamoeba, fungi, viruses and virulent bacteria] can ?hide?, thus reducing a disinfectant?s efficacy.
The previous link is one of those ?must read? articles.
In a similar vein, it now seems that one or more of the three polymer additives in the affected ReNu product actually created a polymeric ?film? that rendered the ReNu disinfectant ineffective.
What have I been saying all these years about multipurpose solutions?
Less is more it would seem.
Nanotech
I've also had to delay reporting on silver-ion coated contact-lens cases. It seems like now is as good a time as any.
The theory is that cases that are internally coated with silver ions or ?nano silver? reduce biofilm development. Another ?must read? for eye nerds, silver fans and biofilm freaks.
Silver nitrate was popular in the old days for treating inclusion conjunctivitis in newborns. It seems nano-silver is a modern interpretation.
CIBA has released the MicroBlock silver-ion case in Europe [and I believe with AQUIFY MPS in Australia]. Check out this in depth article and comparative study. It may raise your eyebrows.
Could we bastardise an old classic and say ?Every case has a silver lining??
As previously reported nanotechnology may also play a role in contact lenses that monitor blood sugar
Keep an eye out for nanotechnology. It's going to change our lives.
Piggybacks Rock
More correctly maybe I should say they often stop the rock and stop the rot. Every week I get referred a number of extreme keratoconics, LASIK complications, RK disasters and other grief cases that are pretty much at the end of the road.
If we fail to rehabilitate these eyes and obtain usable vision, acceptable wear times and comfort, they need keratoplasty or a white stick. It's as simple as that.
In my first years in practise I rarely, if ever, fitted piggyback?s. A sandwich of the low Dk lenses of the day resulted in pretty much no Dk. The only hybrid at the time was no better. I did clinical trials on first-generation hybrids in the mid eighties and thereafter flatly refused to ever fit any. I never did. Ever.
In the ?90s with the advent of disposables and higher Dk RGPs, piggybacking became a more viable option but results were still variable.
Since ?99 and the advent of silicone-hydrogels - coupled with 100Dk Boston XO RGPs - the physiological issues are now no longer a stumbling block.
I've fitted a few over the past years, some with great success.
Cones, grafts and refractive surgery cases have all benefited. A number respond with gratitude and enthusiasm.
It's why we do it. Fiat lux. Lux sit
Lux et veritas
It helps remove the bitter taste of an aberrated bureaucracy.
Veritas lux mea
Lately I've had a run of such piggyback cases. During a week or two in June I saw almost one a day. So far all successful. Happy patients. Some were 5 year aftercares. Others were pleasantly surprised first-time-fits. Two were working fulltime and studying part time. A day at a computer and a night at the books were proving impossible.
We see these cases with increasing frequency: We try to keep them going and receive requests for letters to employers and examiners stating that they just cannot cope.
My lens of choice these days is an Acuvue OASYS which with its high Dk, excellent ?lubricity? and great comfort is proving a winner. UV protection and 123 eversion indicators are an added bonus. I generally use a +0.50D as the front curve seems to aid RGP centration. The actual power of the soft lens sandwich doesn?t seem to alter the over-refraction. Not always.
I've also refitted a few from higher modulus 1st generation si-hy lenses with improvement in comfort, lid reaction and so forth.
Generally speaking one can quickly see if a new lens, eye drop, solution or dietary supplement is a winner. Some take longer to disappoint.
Not many make the grade.
Your own observations coupled with patient feedback and aftercare tells you. Pretty fast.
we're lucky these days to have so many excellent products at our disposal.
For more information or any comments email Alan at incontact@optom.co.nz.