POSITIVE RESULTS FROM NEW DIFFRACTIVE IOL

A new diffractive IOL (FineVision, Physiol) can provide patients with good near, intermediate and distance vision with very little sacrifice of distance vision under mesopic conditions, said Erik L Mertens MD, FEBO, Antwerp, Belgium, at the 16th ESCRS Winter Meeting. In a series of 139 eyes of 70 patients who underwent cataract or refractive lens exchange surgery with the implantation of the FineVision IOL, all reported having achieved complete spectacle independence for all activities, and none reported any significant problems with glare when driving at night, Dr Mertens said. The patients in the study included 70 women and 69 men ranging in age from 47 to 80 years with a mean age of 61 years. Their preoperative spherical equivalent had a mean value of +0.39 D and ranged from -5.75 D to +4.50 D. Their preoperative sphere had a mean value of +0.62 D (range -5.50 D to + 5.00 D) and their preoperative cylinder had a mean value of -0.14 D and ranged from -1.0 D to 0.00 D. Dr Mertens noted that, since the lens itself does not have an astigmatism-correcting component, he used incisional techniques to correct corneal astigmatism in some patients. Sharp acuity over broad range of distances Among 119 patients with one months’ follow-up, the uncorrected distance visual acuity was 20/20 or better in 68 per cent, 20/25 or better in 85 per cent, and 20/30 or better in 97 per cent. Another two per cent were 20/40 and the remaining patients were 20/50 or worse. Regarding near visual acuity at 40cm, monocularly 97 per cent were J2 or better, 52 per cent were J1 or better, and two per cent were J1+ or better. Binocularly, all were J2 or better and 86.0 per cent were J1 or better. The intermediate visual acuity results with the new lens were also very good, all eyes were J2 or better, 69 per cent were J1 or better, and 13 per cent were J 1+ are better. As regards refractive predictability, the mean postoperative spherical equivalent was -0.01 D (range -0.75 to +1.25 D) the mean sphere was 0.06 D (range 0.75 D to 1.50) and the mean cylinder was -0.14 D. In terms of the defocus equivalent, all eyes were within 1.0 D and 88 per cent were within 0.5 D of intended refraction. Aberrometry performed with a Topcon device (KR1W) indicated that eyes implanted with the lens had point spread functions and MTF curves conducive to good vision. The lens induces a mean of -0.1 microns of spherical aberration, he noted. Double diffractive profile Dr Mertens noted that the Physiol FineVision IOL is composed of hydrophilic acrylic material with 25 per cent water content. The lens has a bi-convex, aspheric and trifocal optic 6.15mm in diameter and an overall length of 10.75mm with a 5° angulation of its haptics. It is designed for implantation through a 1.8mm incision. “The lens has four haptics.

It is easily placed into the bag and, of course, the capsulorhexis with these kinds of lenses is very important. It must cover the 360 degrees of the edge of the optic,†he added. The lens achieves its trifocal effect by combining two bifocal diffractive profiles, Dr Mertens said. One diffractive profile combines a distance focus with a +1.75 D addition for intermediate vision and the other diffractive profile combines a distance focus with a +3.50 D addition for near vision, he explained.

Moreover, in order to improve night vision, the lens distributes light in a pupil dependent manner, increasing the amount given to the distance focus as the pupil gets larger, he noted. He said that when using the same targeting imaging as is used by the US Air Force, the Physiol FineVision lens provides a good image of objects at intermediate distance with a 3.0mm and 5.0mm pupil. In contrast, other mulitfocals produce very blurry images of objects at intermediate distances with both 3.0mm and 5.0mm pupil diameters, he noted.

“No patients in our series required glasses for any activities, and although there was glare and haloes at night, it was not significant enough to affect driving. Moreover, this lens provides excellent intermediate vision without a compromise for distance and near visual acuity and so far of all the lenses I've used, it provides the best intermediate vision ever reported with an IOL in my clinic,†Dr Mertens summarised.