At 6 months, 105 patients were available for follow-up. Their mean age was 67.5 years and 57.1% were women. The mean UCDVA in the eyes implanted with small aperture lens improved from 0.57 logMAR to 0.06 logMAR. Mean UCIVA improved from 0.66 logMAR to 0.08 logMAR. Mean uncorrected near visual acuity (UCNVA) improved from 0.75 logMAR to 0.18 logMAR.
By comparison, the UCDVA in the eyes implanted with the monofocal lenses improved from 0.61 logMAR to 0.03 logMAR. UCIVA in these eyes improved from 0.64 logMAR to 0.30 logMAR and UCNVA acuity improved from 0.71 logMAR to 0.51 logMAR.
Binocular UCDVA at 6 months was -0.056 logMAR, uncorrected intermediate vision was 0.043 logMAR and near vision was 0.160 logMAR.
By blocking peripheral defocused light rays, the small-aperture lens not only provides depth of focus, it reduces dysphotopsias, particularly for patients with aberrated corneas like post-refractive or keratoconic patients, Dr. Dick said.
Tolerance to astigmatism
It also provides tolerance to corneal astigmatism up to 1.50 D and a functional range of vision even if the refractive target is missed by as much as 1.00 D MRSE, he said.
“Thus, it would be inaccurate to say that there are zero complaints of glare or halo, but the incidence and severity seem to be by far much less than other multifocal IOLs based on my personal experience,” said Dr. Dick.
In the study, patients rated their visual symptoms on a scale of 0 to 5, where 0 was no symptoms, 1 was very mild and 5 was very severe. They rated blurry vision a mean of 1.09, fluctuating vision 1.0, dry eye 1.4, glare 1.4, halo 1.1, double vision 0.2, and ghost images 0.1.
The researchers performed mesopic contrast sensitivity testing in a subgroup of 36 patients. The eyes with the monofocal IOL had better contrast sensitivity than the eyes with the small-aperture IOL at 1.5 cycles per degree (cpd), 3.0 cpd, 6.0 cpd, and 12.0 cpd.
Binocular contrast sensitivity without glare in eyes with the small-aperture IOL was similar to that in eyes with the monofocal IOL at all spatial frequencies.
Eyes with the monofocal IOL had better monocular mesopic contrast sensitivity with glare than eyes with the small-aperture IOL eyes at 1.5 cpd, 3.0 cpd, and 6.0 cpd. At 12.0 cpd, the difference in contrast sensitivity between eyes with the small-aperture IOL and eyes with a monocular IOL was not statistically significant.
The 114 enrolled patients experienced 14 ocular adverse events: 9 in eyes with the small-aperture IOL and 5 in eyes with the monofocal IOL. The only serious adverse event was 1 case of persistent macular edema in an eye with the small-aperture IOL, but researchers did not consider it to be related to the device.