Implant offers improved UNVA

Bifocal intracorneal implant offers ‘mostly’ spectacle-free everyday life

Roibeard O’hEineachain

Posted: Wednesday, May 1, 2019

Thomas Kohnen,MD,PhD

The monocular implantation of the Presbia Flexivue Microlens bifocal intracorneal inlay can provide presbyopes with a significant improvement in uncorrected near vision (UNVA), at the expense of some loss of monocular uncorrected UDVA and contrast vision, according to the results of prospective, controlled, clinical trial, presented by Thomas Kohnen MD, PhD, at the 23rd ESCRS Winter Meeting in Athens, Greece.
“Patients report a mostly spectacle-free everyday life because of unchanged binocular UDVA,” said Prof Kohnen, Goethe-University, Frankfurt, Germany.
In the study, 25 emmetropic patients with presbyopia requiring a 1.5D to +3.0% D add for near vision underwent placement of the corneal inlay in the nondominant eye. Their preoperative uncorrected UDVA was logMAR -0.08 in the study eye.
The inlays were inserted into a pocket in the corneal stroma created with a femtosecond laser. The implant has a central zone free of refractive power for distance vision and a peripheral zone with a standard positive refractive power to provide corneal multifocality.
Throughout the six months of follow-up, the eyes with the intracorneal implant had significantly better uncorrected near visual acuity (UNVA) than their fellow eyes. That is, in eyes with the implant, mean UNVA was logMAR 0.21 at one week, 0.16 at one month and three months and 0.13 at six months. The UDVA remained unchanged in the eye without the implant.
However, UDVA eyes with the implant were statistically significantly worse, which was logMAR 0.22±0.15 at one month and 0.19 at three months, 0.24±0.17, compared to around logMAR -0.1 throughout follow-up in eyes without the implant. The eyes with the implant also had poorer contrast sensitivity than their fellow eyes. On the other hand, uncorrected binocular distance visual acuity remained stable throughout follow-up.

Good corneal clarity
Prof Kohnen cautioned that two patients had their implants taken out. Following explantation of the IOL, there was a light stromal haze with reduced visual acuity. However, the haze cleared up over time and the patients now have good corneal clarity, Prof Kohnen said.
He suggested that an ideal candidate for this implant would be would be a presbyopic patient, 45-to-55 years old with a clear crystalline lens in whom it could afford a good 10-to-20 years of spectacle independence, after which they may consider using a lenticular approach to multifocality.
“At the moment we have no poor outcomes, we have 23 patients who still have this lens and are happy with this lens,” Prof Kohnen said.

Thomas Kohnen:

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