This multicenter, open-label, prospective analysis evaluated the long-term safety and efficacy of the Kamra small-aperture intracorneal inlay.
Study design
The study comprised 507 patients with emmetropic presbyopia who were aged 45 to 60 years old; 93% completed the 3-year follow up. The intracorneal inlay was implanted in the nondominant eye.
Patients were evaluated for distance, intermediate and near visual acuities and also completed quality-of-vision and satisfaction questionnaires.
Outcomes
At a ≥20/32 vision level, the mean depth-of-focus range improved from 1.7 D preoperatively to 3.0 D at 1 year, with a mean 3-line improvement in uncorrected near visual acuity.
Eyes with a femtosecond pocket made with a 6 x 6 micron spot/line setting had less refractive shift, better acuity and better near task satisfaction. Among those with a femtosecond pocket, deeper inlays resulted in less refractive shift and better uncorrected near vision.
There was about a 5% loss of endothelial cells, with a 1.2 dB mean decrease in mean deviation on Humphrey visual field testing. Six inlays were repositioned, and 44 were removed, with 4 more having a corneal "event." Patients reported a small but statistically significant reduction in satisfaction while watching TV or driving at night.
Limitations
The paper focuses on the outcomes from the 35% of patients who had a femtosecond laser pocket made with a 6 x 6 micron spot/line setting. However, this was a post hoc selection rather than a predefined subgroup. Because this was a population selected for an FDA trial, it may not apply to the patient population at large.
Clinical significance
The findings suggest that deeper femtosecond pockets may improve results with the Kamra corneal inlay. However, a significant percentage of patients (8.7%) still had complications or problems with quality of vision that led to explantation of the inlay.