PURPOSE: To determine the optimum position to center a small-aperture corneal inlay and the
effect of residual defocus in the surgical eye to maximize depth of focus.
SETTING: Laboratorio de Optica, Universidad de Murcia, Murcia, Spain.
DESIGN: Cohort study.
METHODS: Personalized eye models were built using actual data (corneal topography, eye length,
ocular aberrations, and eye alignment). A small aperture 1.6 mm in diameter was placed at the
corneal plane in each model. The monochromatic and polychromatic Strehl ratios were calculated
as a function of the pinhole position. Different residual defocus values were also incorporated into
the models, and the through-focus Strehl ratios were calculated.
RESULTS: Sixteen eye models were built. For most subjects, the optimum location of the aperture
for distance vision was close to the corneal reflex position. For a given optimized centration of the
aperture, the best compromise of depth of focus was obtained when the eyes had some residual
myopic defocus (range 0.75 to 1.00 diopter [D]). Strehl ratio values were over 0.1 for far
distance, which led to visual acuities better than 20/20. The depth of focus was 2.50 D with
a mean near visual acuity of Jaeger 1 or better.
CONCLUSIONS: In eyes with little astigmatism and aberrations, the optimum centration of the small
aperture was near the corneal reflex position. To improve optical outcomes with the inlay, some
small residual myopia and correction of corneal astigmatism might be required.
Financial Disclosure: Dr. Artal is a consultant to Acufocus, manufacturer of the Acufocus Kamra
corneal inlay. Dr. Tabernero has no financial or proprietary interest in any material or method