Technolas 217 is safe and effective in single-site trial

ArF excimer laser with its fluence testing system lets the surgeon adjust the optical zone, leading to fewer reported complications.

NEW YORK — The Technolas 217 ArF excimer laser is reported to be safe and effective in correcting myopia up to 7 D and astigmatism up to 3 D. Tom S. Tooma, MD, discussed a single-site clinical trial of the laser at the Ninth Annual Ocular Surgery News Symposium here. A patient survey showed that 97.7 % of the trial participants were satisfied and would choose to have the surgery again, he said.

The Technolas 217 (Bausch & Lomb) is a flying spot, scanning excimer laser with a beam wavelength of 193 nm, a 2-mm spot size and a repetition rate of 50 Hz. It allows the surgeon to adjust the optical zone up to 7 mm. The laser has an obligatory 3-mm blend zone, with a total ablation diameter up to 10 mm. The fluence at the corneal plane is 120 mJ/cm². It has Zeiss optics and a random spot application pattern. The laser’s ergonomics are patient- and surgeon-friendly, reported Dr. Tooma.

Fluence testing

The Technolas 217 has a unique fluence testing system. A fluence plate made of an orange plastic base covered by a metallic silver material of a precise thickness is used for fluence testing. The laser energy output is adjusted on the computer keyboard by the surgeon so that it would take 65 pulses to ablate the silver lining and reveal the orange plastic plate. If less than 65 pulses are needed to ablate the silver material, the energy is adjusted down, and vice versa, Dr. Tooma explained. The Technolas 217 prevents the surgeon from performing surgery without first performing a fluence test, which typically takes 1 to 2 minutes.

The ablation pattern is accomplished using random spot application. “Each treatment is divided into two, four or eight equal segments depending on the magnitude of myopia and astigmatism,” said Dr. Tooma. “A 4 D correction is split into four segments. In other words, if you stop after the first of four segments in a –4 ablation, you get a perfect 1 D correction. If you stop after the second segment you get a perfect –2 D ablation. The laser stops between the segments, so the surgeon has the opportunity to ask the patient to re-fixate and proceed to the next segment of the ablation,” he said.

Topography illustrates that a 6-mm optical zone ablation can achieve an effective optical zone of up to 7 mm. “With a 7-mm ablation, you can have up to 8 mm or more of an effective optical zone on topography,” Dr. Tooma said.

Clinical trial outcomes

Dr. Tooma reported on a single-center, single-surgeon clinical trial of the Technolas 217. The eyes treated had myopia up to 7 D and astigmatism up to 3 D.

Two hundred eighty-four eyes were included in the study. At the time the data were reported, 103 eyes had reached the 6-month follow-up visit. The mean age was 41.8 years; there were slightly more females than males. The mean preop spherical equivalence was –3.34 D, and at 6 months it was –0.17 D. Mean cylinder was 0.98 D.

Although the surgeon was able to adjust the optical zone from 4 mm to 7 mm with the Technolas 217, all patients were treated with an optical zone between 6 mm and 7 mm, with a total ablation area of between 9 mm and 10 mm. The limbus at 3 and 9 o’clock was marked in patients with more than 1 D of astigmatism, to compensate for cyclotorsion.

“The ACS and the Hansatome microkeratomes were used with an 8.5 mm [suction] ring, except in patients who had corneas flatter than 42 D, in which case a 9.5 mm Hansatome ring was used,” Dr. Tooma said. “At 1 month 89.7% of the eyes had 20/20 or better uncorrected vision, and 87.7% of the eyes were within ± 0.5 D of intended correction.”

At 6 months, 85.4% of eyes had 20/20 or better uncorrected vision, and 100% were within ± 1 D of intended correction. Between 1 and 3 months, 98.5% of the eyes had less than 1 D of change in spherical equivalent correction, and 100% had less than 1 D of change between 3 and 6 months in this group of patients. One month following surgery, 1.9% of patients had two lines or less of loss of best corrected visual acuity (BCVA). Of the patients who were corrected to 20/20 or better before surgery, none of them had 20/25 or worse BCVA.

Six months after surgery, 1% of patients had two lines or less of loss of BCVA, and none had more than two lines of loss.

Complications were few. According to Dr. Tooma, 1% of the eyes had epithelial ingrowth, with loss of less than two lines of BCVA. At the 3-month follow-up visit, no adverse events were reported. There were no corneal abrasions, corneal edema, folds in the flap, misaligned or misplaced flaps or surgical interventions at that time, he said.

For Your Information:

• Tom S. Tooma MD, can be reached at 3501 Jamboree Rd., Ste. 1100, Newport Beach, CA 92260; (949) 854-7400; fax: (949) 509-4898; e-mail: Tom.Tooma@tlcvision.com. Dr. Tooma has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.