Intrastromal presbyopia treatment impresses

September 15, 2008

In a worldwide first, Dr Luis Ruiz presented the preliminary clinical results of an ongoing pilot study concentrating on the non-invasive intrastromal correction of presbyopia.

In a worldwide first, Dr Luis Ruiz presented the preliminary clinical results of an ongoing pilot study concentrating on the non-invasive intrastromal correction of presbyopia.

"The purpose of the study was to quantify the feasibility of non-invasive intrastromal corrections of ametropic eyes, with the first phase focusing on the non-invasive correction of presbyopia," Dr Ruiz told eager delegates.

The Femtec femtosecond laser (20/10 Perfect Vision) applied a customized pattern to the cornea causing a local reorganization of biomechanical forces. In presbyopia, the applied pattern led to a well-defined central steepening of the cornea, resulting in a central increase of refractive power.

"Because the refractive power change is only centrally induced, a significant increase of near vision is evoked, whereas distance vision is only minimally affected," Dr Ruiz said.

The current clinical study features 200 presbyopic eyes and the age of patients ranged from 41 to 66 years with an average of 53.5 ±6.2. A customized pattern was calculated for each eye relative to individual biomechanical and geometrical properties of the cornea. Treatment times ranged between 18 and 30 seconds.

The preliminary results are very promising and encourage further research. Patients gained an average of 6.2 ±2.8 Jaeger lines in near UCVA after three months postop and there were only minor effects on the distance UCVA. The induced increase in acuity has been found to be stable within the observed follow-up time of up to 11 months.

"This non-invasive technique has a huge potential to improve the near vision instantaneously by several lines, according to the Jaeger chart, and so far there has been no long term downsides observed," Dr Ruiz said.

He said the laser induced biomechanical response of the cornea, which causes the beneficial refractive effect on visual acuity, which normally appears in just a few minutes to a few hours postop. "And it shows a high degree of stability during longer observation periods. In distance BSCVA, minimal changes occur after the treatment," Ruiz said. But even this effect is only temporary. One month postop there is an unchanged average BSCVA.

"These promising initial results will need to be further supported by a larger number of procedures performed at several clinical sites in the near future," Dr Ruiz said.

But the technique could go a lot further than presbyopia. "Parallel to the very successful investigation of intrastromal presbyopia correction, further treatment strategies for non-invasive correction of other forms of ametropia, such as myopia, hyperopia and astigmatism, are currently under investigation," Dr Ruiz told delegates.

He said preliminary results for other forms of ametropia are equally promising and indicate that it may be possible to use this technique on all kinds of intrastromal corrections.