Refraction and defocus curves in eyes with monofocal and multifocal intraocular lenses

Surgical interventions for presbyopia

RATIONALE

Presbyopia is a progressive condition that everyone who lives long enough will experience, irrespective of gender, ethnicity, or economic status. A wide range of surgical options has emerged for overcoming near and intermediate visual impairment; however, questions about the effectiveness and safety of these interventions remain unanswered. Given the global burden of presbyopia and the need to improve decision-making practices in tailoring management and allocating scarce resources, it is essential to review the available evidence on this issue systematically.

OBJECTIVES

The primary objective was to compare the effectiveness and safety of surgical interventions for people with presbyopia; the secondary objective was to produce a brief economic commentary summarizing relevant economic evaluations that have compared different surgical interventions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, two other databases, and trial registries on 29 February 2024.

ELIGIBILITY CRITERIA

We included randomized controlled trials in participants with presbyopia, including those who had pseudophakic presbyopia with or without previous corneal refractive surgery, in which one surgical intervention was compared with another or a modified version of the same intervention. We excluded trials that had enrolled participants mainly for cataract surgery or who had other ocular comorbidities such as glaucoma, diabetes mellitus, age-related macular degeneration, or myopic retinopathy.

OUTCOMES

Outcomes of interest were spectacle independence for near and intermediate vision, change in quality of life (QoL), improvement in or maintenance of binocular uncorrected distance visual acuity (VA), participant satisfaction, change in binocular contrast sensitivity (CS), and frequency of adverse events (AE).

RISK OF BIAS

We used the Cochrane RoB 2 tool to assess bias for each outcome in each included trial.

SYNTHESIS METHODS

We planned to synthesize results for each outcome using meta-analysis (random-effect models) where possible, or else use synthesis without meta-analysis methods. However, due to insufficient data for each pairwise comparison (i.e. only one study reported data per analysis), we employed narrative synthesis. We used GRADE to assess the certainty of evidence for each outcome.

INCLUDED STUDIES

We included four studies that enrolled 300 participants (600 eyes); most participants were women; mean ages ranged between 46 and 58 years. Two trials were conducted in Croatia, one in Egypt, and one in Turkey. Three studies compared a surgical intervention for presbyopia with another, and one study compared a surgical intervention with a modified version of the same intervention. All enrolled participants had presbyopia without cataracts, other comorbidities, or previous ocular surgery. No trials were registered before initiation. One trial reported no funding and no financial conflicts of interest; the others provided no information.

SYNTHESIS OF RESULTS

Only one study provided data per pairwise comparison of interventions. No study reported outcomes at 12 months or provided economic data. Diffractive bifocal intraocular lens (IOL) versus refractive bifocal IOL after refractive lens exchange (RLE) At six months, the diffractive bifocal IOL group showed no evidence of a difference in spectacle independence for near vision (risk ratio [RR] 1.06, 95% confidence interval [CI] 0.82 to 1.37; 100 participants; low-certainty evidence), intermediate vision (RR 0.93, 95% CI 0.81 to 1.07; 100 participants; low-certainty evidence), or participant satisfaction (RR 1.09, 95% CI 0.99 to 1.19; 100 participants; very low-certainty evidence) compared with refractive bifocal IOL implantation after RLE. Ocular AEs may be less frequent in the diffractive bifocal IOL group (RR [non-event] 1.38, 95% CI 1.05 to 1.81; 100 participants; very low-certainty evidence). Changes in QoL, binocular CS, or binocular uncorrected distance VA were not reported. Diffractive bifocal IOL after RLE versus laser-assisted in situ keratomileusis (LASIK) monovision At six months, diffractive bifocal IOL implantation showed no evidence of a difference compared with LASIK monovision in spectacle independence for near vision (RR 1.07, 95% CI 0.92 to 1.25; 100 participants; low-certainty evidence), the proportion of participants achieving 0.0 LogMAR or better distance vision (RR 0.87, 95% CI 0.69 to 1.11; 100 participants; low-certainty evidence), or improvement in participant satisfaction (RR 0.98, 95% CI 0.89 to 1.07; 100 participants; low-certainty evidence). However, LASIK monovision may improve spectacle independence for intermediate vision at six months (RR 0.82, 95% CI 0.72 to 0.94; 100 participants; low-certainty evidence) and may reduce ocular AE (RR [non-event] 0.58, 95% CI 0.46 to 0.74; 100 participants; very low-certainty evidence). Changes in QoL or binocular CS were not reported. Diffractive trifocal IOL versus extended depth of focus IOL after RLE No data on spectacle independence, participant satisfaction, binocular CS, or ocular AE were reported. At three months after surgery, neither of the two interventions may offer a clinically significant advantage over the other, either for QoL scores (mean difference [MD] -0.08, 95% CI-0.15 to -0.01; 74 participants; very low-certainty evidence) or binocular uncorrected near VA (MD 0.01, 95% CI -0.02 to 0.04; 74 participants), intermediate VA (MD 0.01, 95% CI -0.01 to 0.03; 74 participants) or distance VA (MD 0.01, 95% CI -0.01 to 0.03; 74 participants; low-certainty evidence). Modified wavefront-guided (WG) LASIK versus conventional WG LASIK We found no data for spectacle independence, QoL, participant satisfaction, or ocular AE. Data from one study suggested no evidence of a difference between the interventions in improvement in uncorrected distance VA or change in binocular CS at three months. However, we had concerns about potential bias, and the data were insufficient for quantitative analysis.

AUTHORS' CONCLUSIONS

The available data were limited to short-term (three months) and mid-term (six months) outcomes and provided low- or very low-certainty evidence. Little information was reported regarding QoL, binocular CS, or ocular AEs; no study addressed economic aspects of interventions.

FUNDING

This Cochrane review had no internal source of support. External sources: National Eye Institute, National Institutes of Health, USA; Public Health Agency, UK; Queen's University Belfast, UK.

REGISTRATION

Protocol (2023): doi.org/10.1002/14651858.CD015711.

A retinal simulation study on the influence of spherical aberration, astigmatism and optotype on the Jackson cross cylinder test

PURPOSE

To study how spherical High-Order Aberration (HOA), astigmatism levels (-0.75 D and -1.25 D), and optotype type (dot pattern vs. letter row) influence patients' responses in identifying the cylinder axis orientation with the Jackson Cross Cylinder Technique (JCCT).

METHODS

Numerical simulations of retinal images corresponding to JCCT procedures were conducted and evaluated by 40 subjects. In order to do this, synthetic aberrometric profiles with and without HOAs (4th-order and 6th-order spherical aberrations) and two different astigmatism levels were generated from different Jackson Cross Cylinder axis positions and flips. The variable under study was the percentage of correct responses (hits) during each flip of the cross-cylinder lens. Statistical significance was assessed through confidence intervals overlapping evaluation.

RESULTS

To achieve 90 % accuracy, the JCCT should begin by deviating >7.5° from the subject's astigmatism axis without spherical HOA and by >15° with them. The magnitude of astigmatism had minor relevance. The dot pattern was more accurate than the letters without HOAs; however, 72.5 % of observers considered that letter optotypes simplify the blur discrimination task.

CONCLUSIONS

According to our simulation experiment for astigmatic axis selection with JCCT, the presence of spherical HOAs significantly impacts the accuracy of patient responses. The type of optotype and the magnitude of astigmatism did not exhibit a clear relationship with accuracy, except in the case of the dot pattern optotype in the absence of HOAs. Under these conditions, the dot pattern achieved the highest rate of accurate responses.

Comparison of visual outcomes in patients with cataracts and high myopia after implantation of a zonal refractive multifocal or diffractive bifocal intraocular lens

This study compares the optical quality of zonal refractive multifocal and diffractive bifocal intraocular lenses (IOLs) and visual outcomes after implantation in 93 patients(93 eyes) with cataracts and high myopia. A retrospective analysis was conducted to measure visual acuity at far, intermediate, and near distances, defocus curves, wavefront aberrations, modulation transfer function (MTF), a Quality of Vision questionnaire (QoV) and visual quality self-evaluation were examined at 3 months. The results demonstrated the ZMB group showed better uncorrected near visual acuity (P < 0.01), and the MF15 group showed better uncorrected intermediate visual acuity (P < 0.001). The ZMB group provided better MTF than the MF15 group (P < 0.01) but demonstrated a worse QoV score, especially for the severity of glare, halo, and starburst (P < 0.05). The satisfaction score and spectacle independence rate in the ZMB group were higher than in the MF15 group (P < 0.01). LS-313MF15 and TecnisZMB00 offered excellent visual restoration, stable distance visual acuity, and good subjective visual function.

Recognition vs resolution charts for defocus curve determination in trifocal intraocular lenses

PURPOSE

To determine the impact of optotype choice on the determination of defocus curve in patients with cataract implanted with presbyopia-correcting intraocular lens (IOL).

SETTING

Oftalvist Alicante, Alicante, Spain.

DESIGN

Observational case-control study.

METHODS

Patients implanted with Asqelio Trifocal IOL participated in this study. Uncorrected and corrected distance visual acuity (VA) and subjective refraction were determined. Monocular defocus curves were obtained 6 months postoperatively with the Clinical Trial Suite system using either Early Treatment Diabetic Retinopathy Study (ETDRS) or Landolt C charts under photopic conditions (85 cd/m 2 ), and range of vergence from +2.00 to -5.00 diopters (D) in 0.50 D steps.

RESULTS

A total of 49 patients were enrolled in the study, 24 in the ETDRS group (7 male, 17 female) and 25 in the Landolt C group (5 male, 20 female). Nonsignificant differences were found between patients conforming both groups, except for preoperative intraocular pressure and white-to-white distance. All patients were within ±1.00 D from intended refraction after surgery. 75% of patients in the ETDRS group and 84% in the Landolt C group were within ±0.50 D. Average difference between the groups across vergences provided by the defocus curve was 0.12 ± 0.05 logMAR units, significant for all vergences ( P < .05). Differences in VA were significant for distance, intermediate, and near between both groups, except for uncorrected distance VA.

CONCLUSIONS

Defocus curves created using Landolt C charts yield significantly lower through-focus outcomes than those created with standard ETDRS charts. This should be taken into account when comparing the performance of presbyopia-correcting systems across studies where recognition charts might have been used because of patient characteristics.

Comparison between cycloplegic and noncycloplegic refraction in young adult myopes

SIGNIFICANCE

This study explores the difference between cycloplegic and noncycloplegic refraction in young adult myopes.

PURPOSE

From the available literature, it is unclear whether cycloplegia is necessary when refracting young adults. This study investigates the agreement between noncycloplegic autorefraction and cycloplegic autorefraction and investigates factors affecting the agreement between the two methods.

METHODS

In total, 125 myopes with ages ranging between 18 and 26 years were included from Australia and Vietnam. Each participant underwent noncycloplegic autorefraction and cycloplegic autorefraction. Cycloplegia was induced with 1% ophthalmic tropicamide.

RESULTS

The mean spherical equivalent difference (95% confidence interval) between noncycloplegic autorefraction and cycloplegic autorefraction was -0.20 D (-0.25 to -0.14 D; t124 = -7.18, p<0.0001 ) . A mean difference of >0.25 D was seen in 46.8% of eyes. The lower and upper limits of agreement were -0.80 and 0.41 D, respectively. With univariate analysis, factors including age, degree of refractive error, accommodation amplitude, and distance phorias showed no impact on the average difference between cycloplegic autorefraction and noncycloplegic autorefraction. Yet, eyes with near exophoria ( F2,120 = 6.63, p=0.0019) and Caucasian eyes ( F3,121 = 2.85, p=0.040) exhibited the smallest paired differences. However, in the multivariate analysis, only near exophoria was associated with a lower mean difference. A significantly smaller proportion (34.9%) of eyes with near exophoria had a paired difference of -0.25 D or more compared with esophoria (50%) and orthophoria (65%; χ2 = 6.6, p=0.038).

CONCLUSIONS

Noncycloplegic autorefraction results in more myopic refractive error than cycloplegic autorefraction in young adults.

Validation of a method to assess night myopia in a clinical setting

A study was conducted with 115 subjects who regularly drove at night to validate a refraction protocol for detecting refractive visual changes from daytime to nighttime conditions. Objective and subjective refractions were performed in both photopic and mesopic conditions, with a dark adaptation period before the mesopic subjective refraction. The results showed that in mesopic conditions, visual acuity decreased by 0.2 logMAR units on average (p < 0.01), and there was a myopic refractive shift of - 0.36 ± 0.20 D (p < 0.01). Most subjects (92.2%) exhibited a myopic refractive shift of at least 0.12 D. Compensation of refractive shift improved mesopic visual acuity by 0.06 logMAR on average (p < 0.01) and higher refractive shifts showed higher improvement. Night Rx was preferred by 82.1% of subjects with myopic refractive shift. Gender and age did not significantly affect the refractive shift, although myopes showed a higher shift compared to emmetropes (p < 0.01). The refractive shift remained stable over time when the time slot of the day did not change (p < 0.01). Night Rx protocol proved to be a robust and accurate method for identifying drivers with refractive changes when transitioning from photopic to mesopic conditions. The high prevalence and inter-individual variability of Rx shift highlight the need of customized refraction.

Optical Performance of a Segmented Extended-Depth-of-Focus Intraocular Lens under the Influence of Different Values of Spherical Aberration Generated by Refractive Surgery

BACKGROUND

Corneal refractive surgery induces high-order aberrations, specifically spherical aberration (SA). These aberrations can have implications when patients later develop cataracts and require the implantation of multifocal intraocular lenses (MIOLs). MIOLs with asymmetric designs pose challenges in predicting outcomes, particularly in these cases. The aim of this study was to evaluate how different values of SA, resulting from various types of refractive surgeries, affect the optical performance of the FEMTIS Comfort intraocular lens.

METHODS

The through-focus modulation transfer function (TF-MTF) curve and high-contrast images of tumbling E were used as parameters to assess the optical performance of the MIOL. These parameters were measured using an adaptive optics visual simulator.

RESULTS

Increasingly negative values of SA make the MIOL more bifocal, moderating its extended-depth-of-focus characteristic. Conversely, higher positive SA values cause the TF-MTF curve to shift towards positive vergences, leading to worsened distance vision in the +1.00 to +2.00 D range, but improved vision in the +0.50 D to +1.00 D range.

CONCLUSIONS

Assessing SA in patients prior to implanting MIOLs with asymmetric designs is necessary for predicting outcomes and making informed decisions based on the visual requirements of patients.