Through‐focus performance with multifocal contact lenses: effect of binocularity, pupil diameter and inherent ocular aberrations

Abstract

Purpose: To evaluate the effects of the wearer's pupil size and spherical aberration on visual performance with centre-near, aspheric multifocal contact lenses (MFCLs). The advantage of binocular over monocular vision was also investigated. Methods: Twelve young volunteers, with an average age of 27 ± 5 years, participated in the study. LogMAR Visual Acuity (VA) was measured under cycloplegia for a range of defocus levels (from +3.0 to À3.0 D, in 0.5 D steps) with no correction and with three aspheric MFCLs (Air Optix Aqua Multifocal) with a centrenear design, providing correction for 'Low', 'Med' and 'High' near demands. Measurements were performed for all combinations of the following conditions: (1) artificial pupils of 6 and 3 mm diameter, (2) binocular and monocular (dominant eye) vision. Depth-of-focus (DOF) was calculated from the VA vs defocus curves. Ocular aberrations under cycloplegia were measured using iTrace. Results: VA at À3.0 D defocus (simulating near performance) was statistically higher for the 3 mm than for the 6 mm pupil (p = 0.006), and for binocular rather than for monocular vision (p < 0.001). Similarly, DOF was better for the 3 mm pupil (p = 0.002) and for binocular viewing conditions (p < 0.001). Both VA at À3.0 D defocus and DOF increased as the 'addition' of the MFCL correction increased. Finally, with the centre-near MFCLs a linear correlation was found between VA at À3.0 D defocus and the wearer's ocular spherical aberration (R 2 = 0.20 p < 0.001 for 6 mm data), with the eyes exhibiting the higher positive spherical aberration experiencing worse VAs. By contrast, no correlation was found between VA and spherical aberration at 0.00 D defocus (distance vision). Conclusions: Both near VA and depth-of-focus improve with these MFCLs, with the effects being more pronounced for small pupils and for binocular rather than monocular vision. Coupling of the wearer's ocular spherical aberration with the aberration profiles provided by MFCLs affects their functionality.

Short-term comparison between extended depth-of-focus prototype contact lenses and a commercially-available center-near multifocal

“…The present study indicates similar findings with EDOF lenses showing better intermediate and near vision performance and similar distance vision when compared to a center-near design multifocal (AOMF). Similar to our previous study, 22 possible confounders to multifocal performance including pupil size, 10 illumination levels 10 and lens fitting15, 26 were minimized by the cross-over design, controlled illumination levels and no significance difference between lens types for any lens fitting parameters. The non-significant interaction for HCVA, clarity-of-vision and lack-of-ghosting between lens types and strata suggests inferences with the total sample size are also applicable to the low and medium-high presbyopia strata.…”

Compensation of Presbyopia With the Light Sword Lens

“…To mimic presbyopia, cycloplegia was induced by applying 2 drops of 1% tropicamide ophthalmic solution at the beginning of the experimental session and 1 extra drop after each hour of measurements; this is a standard procedure in this kind of study. [31][32][33] We found the BCDVA using the BLS after induction of cycloplegia. The FIGURE 2.…”

Visual Performance of a Multifocal Contact Lens versus Monovision in Established Presbyopes

“…Visual quality through MFs is known to be compromised in both eyes because of the increased aberrations demonstrated among different designs and addition powers of simultaneous MF lenses, 14,29 as well as because of the degradation of the retinal image attributed to loss of contrast. The differences in the ''problems'' reported by subjects in this trial were interesting.…”