Adaptation to Brightness Perception in Patients Implanted With a Small Aperture

Small-aperture intracorneal inlay implantation in emmetropic presbyopic patients: a systematic review

Small-aperture corneal inlays, commonly known as KAMRA, are tiny optical devices inserted in the corneal stroma aiming to gain near vision in patients with presbyopia. The purpose of this study was to systematically review case series of small-aperture corneal inlays performed in presbyopic emmetropic patients and to evaluate the visual outcomes of this procedure. This systematic review included 18 articles published between 2011 and 2018, overall studying 2724 eyes from 2691 participants. The mean longest follow-up was 19 months. Results showed that 78.5% of eyes reported an uncorrected near visual acuity of 20/32 or better and 90.50% of eyes achieved an uncorrected distance visual acuity of 20/25 or better. All patients experienced an improvement in uncorrected near visual acuity with a patient satisfaction ranging between 60% and 90%. The highlighted complications were keratocyte activation leading to corneal stromal haze, epithelial growth, iron deposits and poor distance visual acuity. Explantation was carried out in 101 eyes (3.7%) due to distance vision blurriness, development of epithelial microcysts, incorrect implant placement or hyperopic shift changes. KAMRA demonstrated high efficacy. However, safety and satisfaction rates remain unclear. Despite the low explantation rates reported in the literature, some complications were permanent. The results and conclusions should be taken with caution due to the conflict of interest stated in the reviewed articles.

Bilateral implantation of a supplementary intraocular pinhole

PURPOSE

To evaluate the safety and efficacy of bilateral implantation of a supplementary small-aperture device to treat irregular corneal astigmatism.

SETTING

Private practice.

DESIGN

Retrospective consecutive case series.

METHODS

Patients with bilateral irregular corneal astigmatism secondary to multiple causes and consented for implantation of the XtraFocus intraocular pinhole (IOPH) were enrolled. The mean follow-up was 27 months (range 5 to 66 months). Patients were assessed in their scheduled follow-up visits and monocular and binocular uncorrected and corrected distance and near visual acuities were recorded. Assessment of darkening vision complaints was also performed after implantation in the first eye and repeated after second-eye surgery.

RESULTS

Thirty-two eyes of 16 patients were analyzed. The mean monocular and binocular uncorrected distance visual acuities improved from logMAR 1.091 ± 0.208 and 1.078 ± 0.259 preoperatively to 0.342 ± 0.091 (P < .001) and 0.342 ± 0.147 (P = .001) 1 year postoperatively. Three patients were excluded because of darkening vision complaints after surgery in the first eye. No major complications were noted after implantation of the IOPH.

CONCLUSIONS

Bilateral implantation of the XtraFocus IOPH is a safe technique in a selected group of patients. There was improvement in visual acuity sustained over the analyzed period. Postoperative darkening vision complaints vary between individuals and can limit the application of this approach in certain patients.

Small-aperture optics for the presbyope: do comparable designs of corneal inlays and intraocular lenses provide similar transmittances to the retina?

The near-vision performance of emmetropic presbyopes can be improved by the monocular surgical implantation of small-aperture corneal inlays or intraocular lenses that contain either an annular or circular stop to increase ocular depth of focus. Ray tracing is used to show that, although different stop designs and positions may produce similar axial imagery and increases in depth of focus, off-axis, the vignetting effects associated with the distance between the stop and the iris aperture result in different field dependences for the pupil transmittance. The implications of these effects, and of implanting a stop in only one eye, are discussed.