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Lepto-LASIK improves visual outcomes and safety of LASIK, surgeon says
The procedure prevents complications and shows significant improvement in contrast sensitivity and wavefront refraction, according to its developer.
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All images courtesy of Etienne Hachet, MD. |
PARIS – A new way of performing LASIK, with a flap of less than 100 µm, spares tissue and results in better optical quality, according to one surgeon.
“Compared with standard LASIK, contrast sensitivity is better and there is a consistent reduction of higher-order aberrations,” said Etienne Hachet, MD, speaking here at the meeting of the French Society of Ophthalmology.
His technique, named lepto-LASIK from the Greek leptós or thin, is like standard LASIK in all respects except the thickness of the flap.
“In the standard LASIK procedure the flap is created within the stroma at a depth of 130 µm to 180 mm. The epi-LASIK technique produces an epithelial flap of less than 60 mm between the basement membrane and the Bowman’s layer. The lepto-LASIK cut is performed somewhere in between, in the stromal layer approximately 30 mm under the Bowman’s membrane at a depth of about 80 mm,” he explained.
Advantages
There are many reasons in favor of a more superficial LASIK cut, Dr. Hachet said. Histologically, at the upper layers of the cornea, the stroma is denser than in the deeper layers, and cells are smaller, more regularly distributed and more compact, he said.
“Cutting through this denser layer is easier than down below, where the stroma is looser and softer. The quality of the cut is better, surfaces are smoother and the flap will adhere better to the stromal bed after the treatment,” he said.
Another advantage is that there is more corneal thickness available for the treatment.
“Between flap and ablation, we remain within 160 mm of corneal thickness. In other words, with an 80 mm flap we have enough residual stromal thickness left to treat comfortably a myopia of 5 to 6 D or more,” he said.
Moreover, larger optical zones can be obtained with a lesser depth of ablation.
Finally, thinner flaps offer more mechanical corneal strength and, consequently, cut down on the chances of developing corneal ectasia, he said.
Remarkably better
To perform lepto-LASIK, Dr. Hachet uses the Moria One microkeratome with a special head marked 80. All other parts of the machine are the same used for standard LASIK.
“There’s nothing new you have to learn. The machine is just the same old user-friendly, completely manual, autoclavable microkeratome you are used to,” he said.
After the flap has been lifted, Dr. Hachet performs the ablation with the Zeiss-Meditec MEL 80 WASCA laser system, and then replaces the flap on the stromal bed.
According to Dr. Hachet, there are no problems performing or handling thinner flaps. In the cases he has treated there have been no buttonholes, free cups or irregular cuts. Stroma-to-stroma adhesion was perfect in all eyes, and postoperatively there were no cases of abnormal scarring, microfolds or striae.
Functional results were also much better than in standard LASIK, he said.
According to Dr. Hachet, visual recovery was faster, taking place within 12 hours or by the morning following surgery.
Visual quality was also remarkably better, with contrast sensitivity high in all patients, he said. “Higher-order aberrations on a diameter of 6 mm were less than preoperatively. No patient complained of night glare and halos,” Dr. Hachet pointed out.
He noted that these outcomes are quite atypical of LASIK, which is usually associated with contrast sensitivity loss and surgery-induced higher-order aberrations. A comparison with patients treated with standard flaps on the same optic diameter using the same customized laser program confirmed lepto-LASIK’s trend of better contrast sensitivity and fewer higher-order aberrations, he said.
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A critical role
Dr. Hachet said his results confirm the critical role of the corneal flap to the success of LASIK. Intraoperative and postoperative complications are frequently associated with the flap, and so are visual outcomes, with respect to visual quality in particular.
“Lepto-LASIK is as fast as LASIK, has the same stability of results and the same comfort for the patient. On the other hand, it has all the advantages of a thinner flap, including the lesser chances of late ectasia. On top of this, it provides a better optical quality, comparable to that of LASEK and PRK,” he concluded.
For Your Information:
- Etienne Hachet, MD, can be reached at 3 cours Léopold, 54000 Nancy, France; 33 3 83351506; fax: 33 3 83354042; e-mail: perso.hachet@wanadoo.fr.