Toric IOL Alignment

A specialised image-guided axis reference system offers surgeons an effective and efficient means of accurately aligning toric intraocular lenses (IOLs) and has some advantages compared to traditional ink marking methods, according to Gilles Lesieur MD, speaking at the French Implant and Refractive Surgery Association (SAFIR) annual meeting in Paris.

“While our prospective study showed that precision is not increased for an experienced surgeon who is used to dealing with the limitations of traditional toric lens markings, there are other advantages using software for toric lens alignment,” said Dr Lesieur.

“The ease and speed of using an automated image marker significantly improves the flow of patients through the operating room, saving an average of three minutes per patient. There is also a benefit for the patient in terms of less manipulation,” he added.

Dr Lesieur’s study included 45 eyes implanted using traditional ink marking methods on the cornea for toric IOL alignment and 51 eyes without ink marking using the Callisto Eye system (Carl Zeiss Meditec). All eyes implanted with a toric IOL were followed with the Goniotrans 1.1 software application, which is available free for download and runs on Microsoft Windows PC and iOS devices. The Goniotrans software uses a virtual protractor superimposed over the image of the eye to analyse the toric IOL alignment, said Dr Lesieur.

360-DEGREE ROTATION

The implant selected in all patients was the AT TORBI 709M/MP toric IOL (Carl Zeiss Meditec), a 25 per cent hydrophilic acrylic lens with a hydrophobic surface, which is very stable in the capsular bag with minimal rotation or decentration, said Dr Lesieur. Unlike some other toric lenses, which only allow clockwise rotation, the AT TORBI has been designed to enable 360-degree rotation in either direction, making it easier to align and fine-tune on the target axis.

Turning to the results, Dr Lesieur said that there was no statistically significant difference between the two marking methods in terms of the final assessed rotational stability of the lens. “Using traditional marking methods, 91 per cent of the lenses had less than 10 degrees rotation, compared to 90.5 per cent for image-guided,” said Dr Lesieur.

Summing up, Dr Lesieur said that while traditional toric marking did not pose a problem for an experienced surgeon, the ease of use of the image-guided system and its comfort for patients were two compelling arguments for its adoption. Furthermore, the device can be used for other applications such as capsulorhexis projection, keratoscopy and limbal arciform incisions, concluded Dr Lesieur.

Gilles Lesieur: g.lesieur@centre-iridis.fr