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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



Allegretto promising for hyperopia and hyperopic astigmatism

By Cheryl Guttman

PHILADELPHIA - The AllegrettoTM (WaveLight) laser appears promising for the treatment of hyperopia and hyperopic astigmatism, suggest early results from an ongoing FDA trial presented at the annual ASCRS Symposium on Cataract, IOL and Refractive Surgery.
Charles R. Moore MD reported six-month data for 197 eyes treated for up to +6.0 D of hyperopia and up to 5.0 D of cylinder. The majority of eyes had between +1.0 D and
+3.0 D of hyperopia and less than 1.0 D of astigmatism.

A little more than 70% of eyes were within 0.5 D of target spherical equivalent (SE) at the one, three and six month visits. At six months, UCVA was 20/40 or better in 89%; 20/20 or better in 72%; and 20/16 or better in 41%.

The BSCVA results showed excellent safety - only 1.5% of eyes lost two lines or more but 50% gained one or two lines of BSCVA at six months.
"The Allegretto is showing itself to be an outstanding laser. The high predictability of the refractive outcomes has been especially gratifying and it appears we have stability at three months and perhaps as early as one month.

"Moreover, this is the only laser I have had experience with that results in such high proportions of hyperopic patients achieving 20/16 UCVA and gain one or more lines in BSCVA," Dr Moore said.

He added that the FDA efficacy criteria do not even include a target for 20/16 UCVA. In the six-month analyses, this study cohort exceeded the existing UCVA requirement for 50% of eyes to see 20/20.

The laser also surpassed the FDA safety criteria for loss of two or more lines of BSCVA to occur in less than 5% of eyes.

The impressive performance of the Allegretto is further illustrated by comparing these interim outcomes with the results achieved in the hyperopia/hyperopic astigmatism trials with the Star 3TM (Visx) and LadarVisionTM (Autonomous) excimer lasers, Dr Moore said.
While nearly three-quarters of Allegretto-treated eyes are seeing 20/20 uncorrected, that level of UCVA was achieved by only 46% of eyes in the Visx study and 43% in the Autonomous trial.
Furthermore, only 1.2% of eyes in the FDA trial have lost two or more lines of BSCVA while that amount of loss occurred in 5.4% of eyes in the Autonomous trial and 3.7% of those treated in the VISX study, Dr Moore reported.

The Allegretto hyperopia/hyperopic astigmatism LASIK study is being conducted at 11 investigational sites. Surgeons are using four different types of microkeratomes and following a single nomogram.
The laser is driven by a laptop connected to software which allows immediate outcome analysis and determines the need for algorithm changes. So far, no changes have been necessary in the hyperopia trial, Dr Moore observed.

"The absence of any need for algorithm adjustments has been a pleasant surprise to all the investigators. The sphere nomogram has turned out to be a straight line and this laser was built to avoid cylinder coupling. And that phenomenon has not been identified," Dr Moore said.

The Allegretto laser features a 0.95 mm flying spot with a Gaussian beam profile and a 250 Hz video-based small pupil active tracker with a response time of less than
6.0 msec.

In addition, it has a very high fluence (200 mJ/cm2) and a fast repetition rate of 200 Hz. As a result, peripheral ablation accuracy is high and the treatment itself is very rapid. It takes just six seconds to correct 1.0 D of myopia and 10 seconds for every 1.0 D of hyperopia.

"The first time I ever used this laser it stopped so soon after I put my foot on the pedal that I asked the technician what was wrong. She told me nothing, you're finished," Dr Moore said.
WaveLight Laser Technologie AG has its headquarters in Erlangen, Germany and is distributed worldwide by Lumenis Inc. Dr Moore has no financial interest in the company.

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