Background: To compare objective electrophysiological contrast sensitivity function (CSF) in patients implanted with either multifocal intraocular lenses (MIOLs) or monofocal intraocular lenses (IOLs) by pattern reversal visual evoked potentials (prVEP) measurements.
Methods: Fourty-five cataract patients were randomly allocated to receive bilaterally: apodized diffractive-refractive Alcon Acrysof MIOL (A), full diffractive AMO Tecnis MIOL (B) or monofocal Alcon Acrysof IOL (C). Primary outcomes: 1-year differences in objective binocular CSF measured by prVEP with sinusoid grating stimuli of 6 decreasing contrast levels at 6 spatial frequencies. Secondary outcomes: psychophysical CSF measured with VCTS-6500, photopic uncorrected distance (UDVA), and mesopic and photopic uncorrected near and intermediate visual acuities (UNVA and UIVA respectively).
Results: Electrophysiological CSF curve had an inverted U-shaped morphology in all groups, with a biphasic pattern in Group B. Group A showed a lower CSF than group B at 4 and 8 cpd, and a lower value than group C at 8 cpd. Psychophysical CSF in group A exhibited a lower value at 12 cpd than group B. Mean photopic and mesopic UNVA and UIVA were worse in monofocal group compared to the multifocal groups. Mesopic UNVA and UIVA were better in group B.
Conclusions: Electrophysiological CSF behaves differently depending on the types of multifocal or monofocal IOLs. This may be related to the visual acuity under certain conditions or to IOL characteristics. This objective method might be a potential new tool to investigate on MIOL differences and on subjective device-related quality of vision.
Abstract: Cataract surgery is one of the most commonly performed surgeries among the elderly today. The volume of cataract surgeries has dramatically increased in the past few decades due to technological advancements leading to decreased morbidity, better overall outcomes, and increased expectation for correction of refractive error and spectacle independence after cataract surgery. The number of cataract surgeries is expected to continue to rise with the increase of the elderly population. Thus, accurate predictions of intraocular lens (IOL) power and the ability to correct for any postoperative refractive errors are critical. Despite the improved ability of cataract surgeons to accurately calculate IOL power, postoperative refractive errors still do occur due to various reasons such as imperfect preoperative measurements, toric-lens misalignment, and existing or surgically-induced astigmatism. The aim of this article is to review the various surgical options, including intraocular and corneal refractive surgical approaches, to correct post-operative refractive errors after cataract surgery.
Background: Surgically induced astigmatism (SIA) and corneal high-order aberrations (HOAs) are the two main causes of poor visual quality after cataract surgery. Changes in the parameters of corneal HOAs after cataract surgery and their effects on and relationships with changes in corneal curvature have not yet been reported. This study aimed to explore changes in anterior, posterior and total corneal curvature, astigmatism and HOAs after microincision cataract surgery.
Methods: Sixty-one age-related cataract patients (61 eyes) were included in this prospective study. The total, anterior and posterior corneal astigmatism and corneal HOAs were analyzed by anterior segment optical coherence tomography (AS-OCT) and iTrace before, one day, one week and three months after 2.2 mm temporal microincision coaxial phacoemulsification to evaluate the changes in anterior, posterior and total corneal curvature, astigmatism and corneal HOAs.
Results: The mean J0 and J45 values of anterior, posterior and total corneal curvature obtained by AS-OCT showed no statistically significant difference between preoperatively and any postoperative follow-up. SIA occurred on the anterior, posterior and total corneal surfaces and showed no statistically significant difference at any postoperative follow-up. No significant changes in 3rd-order oblique trefoil, vertical coma or 4th-order spherical aberrations were observed after surgery except for a significant increase in horizontal coma at postoperative day 1 (POD1).
Conclusions: There were no significant changes in corneal curvature after 2.2 mm temporal microincision coaxial phacoemulsification, and the corneal HOAs were not changed significantly except for the increase in horizontal coma at POD1, which may be one of the main reasons of poor visual quality at POD1 in some cataract patients who have good uncorrected or corrected distance vision.
