Depth of focus as a function of spherical aberration using adaptive optics in pseudophakic subjects

To measure visual acuity at three different defocus planes in pseudophakic subjects with varying levels of spherical aberration induced by an adaptive optics visual simulator. The study aimed to simulate Extended Depth of Focus (EDOF) intraocular lenses (IOLs).

Private hospital (IMO, Barcelona, Spain).

Observational case series; modelling theory.

Through-focus visual acuity was measured in 26 pseudophakic subjects (age 63 ± 10 years old) with an adaptive optics visual simulator optimized for clinical use (VAO, Voptica SL, Murcia, Spain). Measurements were made under five different conditions of induced negative spherical aberration: 0, -0.07, -0.15, -0.23 and -0.30 μm (pupil diameter: 4.5 mm). Results were also modelled using ray tracing simulations.

On average, depth of focus was extended when spherical aberration increased from -0.07 to -0.15 μm (4.5 mm pupil diameter). Some indivisuals (27%) experienced improved depth of focus with higher magnitudes of spherical aberration, while others (23%) exhibited no benefit from increased (negative) SA, as visual acuity dropped below acceptable levels. Depth of focus calculations based on ray tracing showed general agreement with the measurements.

The visual conditions of EDOF IOLs were artificially recreated in a population of pseudophakic patients implanted with a monofocal IOL. The variability seen across subjects in visual acuity at different defocus planes suggests that visual simulators might be capable of screening subjects for suitability and tolerability of these advanced technology lenses.