DEC 10, 2020
Cataract/Anterior Segment, Refractive Mgmt/Intervention
The authors evaluated the outcomes of bilateral toric extended depth-of-focus intraocular lens (EDOF IOL) implantation targeted for micromonovision.
This was a single-site, prospective case series study that included 52 eyes of 26 patients with regular corneal astigmatism from 0.75 to 2.60 D that were implanted bilaterally with a toric EDOF IOL targeted for micromonovision. The authors assessed postoperative visual acuity, astigmatism reduction, rotation, tilt, decentration, spectacle independence, patient satisfaction and photic phenomena.
This study highlighted the use of diffractive optics. The dominant eye was targeted for emmetropia. The non-dominant eye was targeted a minimal residual myopia of -0.5 D. Study patients achieved superior UDVA and UIVA with improved UNVA due to the micromonovision. The use of toric EDOF IOL implantation targeted for micromonovision resulted in reliable reduction of preoperative astigmatism with a high degree of postoperative rotational predictability and centration, enabling functional distance, intermediate and near vision, which manifested itself in high patient satisfaction.
The biggest controversy in this study is that there is no objective quantification of the postoperative visual disturbances often associated with diffractive optics. Specifically, there is known increased visual disturbances once the spherical equivalent deviates from plano. Therefore, the biggest limitation would not be whether the IOLs produced a reliable result, but that real-world patients tolerated the lenses well. Another difficulty with the published data is the distance that they measured UDVA of 4 m. This would have created an artificially residual postoperative SE that was slightly more myopic. The only benefit for this not causing major issues with the data is that the enhanced depth of focus platforms are able to help overcome this myopia by blending vision throughout a range rather than just 2 to 3 focal points as with previous multifocal lenses.
Toric lenses continued to be adopted at an alarmingly low rate. But why? Available data suggest the lenses perform incredibly well throughout ranges of vision with many different technologies. Even in premium EDOF technologies, this study highlights how beneficial a toric lens is in reducing a patient’s astigmatism. It would appear that if there is a change in the reimbursement of toric IOLs in the United States, these lenses would be adopted at a much higher rate.