ESCRS Homepage

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



Mitomycin-C provides effective haze prophylaxis

By Cheryl Guttman

PHILADELPHIA - Intraoperative mitomycin-C offers at least short-term safety and efficacy in mitigating haze risk in high myopes undergoing PRK, according to reports at this year's annual ASCRS conference.

Sufia Siddique MD reported the results of a study comparing a prospectively treated group of high myopes receiving a single intraoperative dose of mitomycin-C 0.02% and a historical control group matched by age and prescription that underwent PRK without mitomycin-C.
There were 40 eyes in each study arm and mean preoperative spherical equivalent (SE) was about -10 D for both cohorts.

In the primary outcome assessment performed after one year, clinically significant haze - defined as requiring long-term steroid treatment or surgical removal - had occurred in none of the eyes receiving mitomycin-C prophylaxis compared to 17 (42%) eyes in the control group.
Other analyses showed benefits for mitomycin-C prophylaxis. For example, 70% of treated eyes were within one line of baseline BCVA with one surgery. That compared to 42% of untreated eyes.

Similarly, 78% of mitomycin C treated eyes did not require re-treatment for residual myopia and/or haze compared to 45% in the control group.
"We were impressed by the results in secondary cases. The concentration of mitomycin-C we were using was far below the cytotoxic level so we decided to use it prophylactically in high myopes. Our results so far have been very promising.
"We feel this intervention has value for high myopes undergoing PRK for whatever reason. However, we recognise that it is a preliminary study and look forward to longer-term, double-blind trials from multiple centres to corroborate our results," Dr Siddique said.

The refractive corrections were performed using a transepithelial, multipass/multizone, no-touch technique.
After PRK, the mitomycin-C was painted onto the cornea with a brush followed two minutes later with copious irrigation and application of a bandage contact lens.
Postoperative treatment included fluorometholone 0.1% with dose and duration adjusted over time depending on the degree of hyperopia.

Treatment with mitomycin-C was associated with increased symptoms of pain, lacrimation and photophobia as well as slightly greater corneal oedema in the immediate postoperative period.

In addition, delayed regression of hyperopia was observed causing symptoms of asthenopia. Among mitomycin-C treated eyes, 50% remained overcorrected by more than +1.0 D at 3 months compared to none of the control eyes. But the incidence of eyes with greater than +1.0 D overcorrection had declined to 5% by the end of the study.

Delayed recovery
"When using mitomycin-C prophylactically, it is important to include information about a possibility of delayed recovery in the informed consent," Dr Siddique said.
David Edmison MD, Medical Director, Focus Eye Centre, Ottawa, Canada, reported his experience using mitomycin-C prophylaxis in 102 eyes undergoing primary PRK for treatment of high myopia (-9.0 D to -15 D).

After a mean follow-up of 18 months, the incidence of haze was 1.9%, representing about a 2.5-fold reduction on Dr Edmison's previous experience treating high myopia without intraoperative mitomycin-C.

"Other surgeons have reported that haze develops in at least 10% of eyes treated with PRK for high myopia but our rate has been lower thanks to the use of a cold technique that incorporates the use of all chilled drops.

"Nevertheless, these results show that by combining that approach with prophylactic mitomycin-C, we can further reduce the risk of haze," Dr Edmison observed.
Mitomycin-C was generally safe, although Dr Edmison reported some postoperative phenomena.

Re-epithelialisation was delayed by about 24 hours in an estimated 10% to 15% of eyes treated with adjunctive mitomycin-C.
Some patients showed a slower visual recovery to target and approximately 20% of eyes were over-corrected by more than +1.0 D.

"If mitomycin-C is used in this setting, patients should be informed of the potential for slower visual rehabilitation, although they can expect to be able to see well enough to drive within two weeks.
"Due to the over-corrections which have occurred with the use of mitomycin-C, I would suggest reducing the treatment by at least 1.5 D," Dr Edmison said.



Top