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November 2002
IN THIS ISSUE

Wavefront seeks a higher order of vision correction
New laser system for intraoperative measurement of LASIK flap thickness
Visual prostheses use neurotransmitter retinal chips to stimulate retinal function
Wavefront emerges as powerful tool for night vision
Allegretto promising for hyperopia and hyperopic astigmatism
Topography's role in wavefront systems
IOP measurement after LASIK may be unreliable
LASEK may only play support on refractive stage
Solid-state laser PRK yields favourable results for myopia
GTS-assisted DLK useful alternative to PK for keratoconus
Glaucoma common after PK bodes poorly for visual outcome
Classic drawbacks of PRK succumb to new strategies
New insight into LASIK dry eye pathogenesis
Use of anti-inflammatories after capsulotomy questioned
Good quality training leads to good quality cataract surgery
One line of regained visual acuity is a snip at just €120
Mitomycin-C provides effective haze prophylaxis
Long-term concerns linger on safety of Mitomycin-C
German politicos promise health reforms
Honey forms biblical basis for corneal oedema
Routine two-step LASIK after PK unnecessary
Plasma knife provides clean and accurate cut for capsulorhexis
Glaucoma therapy targets apoptosis and trabecular meshwork
Viscocanalostomy viable choice for cataract-glaucoma
Device allows needle-free injections into smallest vessels
New river blindness therapy may provide panacea for 18m people
Daytime running lights may soon be compulsory in all EU states
Intracorneal lamellar implants still a questionable option
Aqualase system viable for small incision cataract removal
Unilateral von-Hippel disease with optic nerve head
FEATURES
From The Editor
Reflections on Refractive Surgery
In Your Good Books
An Eye On Travel
Bio-ophthalmology
Outlook on Industry
Regulatory Matters



Viscocanalostomy viable choice for cataract-glaucoma

By Cheryl Guttman

PHILADELPHIA - Viscocanalostomy can be combined safely and effectively with phacoemulsification for the routine cataract patient with glaucoma, reported H. Wade Faulkner MD at the annual ASCRS Symposium on Cataract, IOL and Refractive Surgery.

Dr Faulkner, who specialises in cataract/IOL surgery, reported that he has converted his combined cataract-glaucoma surgeries exclusively to phacoemulsification with viscocanalostomy from phacotrabeculectomy.
That surgical approach is supported by an analysis of data from his first 200 consecutive eyes that underwent the non-penetrating glaucoma procedure with cataract extraction.

The results showed very high success rates in terms of IOP control, few complications and overall a marked reduction in the need for postoperative care.
All eyes in the series had a minimum follow-up of 12 months. The average follow-up time was 36 months, ranging as high as 56 months.
All patients were receiving some medication for their glaucoma, with IOP averaging 19 mm Hg before the combined surgery.

At the last visit, average IOP was 14 mm Hg and 89% of eyes had IOP of 20 mm Hg or less without medication. The rest were qualified successes, requiring minimal anti-glaucoma medication to maintain acceptable IOP.
Outcomes were similar in the 49 African-American eyes in the study compared with the overall patient population.
Complications included re-operation with argon laser trabeculoplasty in two eyes, one flat chamber, five transient hyphaemas and one eye in which the Descemet's membrane was stripped.

Bleb problems were avoided and there were no choroidal detachments or cases of hypotony, Dr Faulkner reported.
"Six years ago we analysed our practice experience with trabeculectomy and bleb headaches over a 12-month period and the results led us to conclude that when it comes to blebs, we were living under Frankenstein's Law - we made the monster and we had to take care of it.

"Viscocanalostomy seemed to offer a good alternative that might be combined safely with phacoemulsification. This data confirms that impression. What has been important to me as a practitioner is that the favourable outcomes are achieved with no greater commitment to postoperative care than is required for routine phacoemulsification," Dr Faulkner said.

The average number of medications per patient declined from 1.4 preoperatively to 0.1 postoperatively. Among 24 patients restarted on medication, the average time to reinitiation was 36 months after the combined procedure.
However, 60% of cases restarting on medication did so within the first two months after surgery. After that, the number of eyes returning to medication increased gradually and over the last six months, no new patients returned to medication.

"It seems that most failures occur early. Hopefully, once that period is passed, the control will continue in the long term," he noted.
Temporal analyses of IOP data illustrate the well-known learning curve for viscocanalostomy. Dr Faulkner reported that during the first six months of the series, he operated on 35 eyes of which 13 (54%) achieved an IOP of
16 mm Hg.

In contrast, among the 165 eyes operated on over the next four years, 132 (80%) achieved that IOP level. Only 8% of 165 eyes operated on during the last 48 months were put back on medication.

To perform the combined procedure, Dr Faulkner uses a temporal, clear corneal incision with a phaco flip technique for cataract removal. He implants the IOL and then does the viscocanalostomy through a separate site at a superior temporal location.
"The primary reason I do a two-site operation is that I am most comfortable performing temporal clear cornea phaco.

"However, as another benefit, I have found that this approach avoids the phacochemosis that can be troublesome when the conjunctiva blooms and pools spill over the cornea. In addition, a phaco burn could compromise the viscocanalostomy site," he explained.

Dr Faulkner noted he saves the anterior capsule, which is used later in the viscocanalostomy, and routinely implants the IOL before the glaucoma surgery after having experienced a few cases where the trabeculo-Descemet's window ruptured when the implant was placed later.

He noted that he always leaves a small amount of Healon 5 (2.3% sodium hyaluronate) in the corneal dome after the IOL implantation to protect the endothelium when the chamber is collapsed after Schlemm's canal is opened.
The eye is decompressed through the cataract wound, thereby assuring Descemet's membrane remains intact when it is separated from the peripheral part of the cornea after dissection of the superficial and deep scleral flaps.

Next, viscoelastic is injected into the open end of Schlemm's canal, delivering five to seven pulses to ensure good dilatation. Afterwards, the deep scleral flap is excised and a scleral lake created.

The preserved anterior capsule tissue is put into the viscoelastic-filled space and the superficial flap closed tightly using a 10-0 Ethilon suture. The conjunctiva is cauterised to close it.

"My hope is that the anterior capsule will act as an implant to maintain the space patent for a longer period of time. However, I have to be especially careful this tissue does not form a wick at the edge of the wound," Dr Faulkner said.

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