Reading performance with a refractive multifocal and a diffractive bifocal intraocular lens

Toward an internationally accepted standard for reading charts

Patients who suffer from sight-threatening eye diseases share a desire to regain a comfortable reading ability. In light of the modern advances achieved in ophthalmic diagnosis and therapy, and because a significant lack of comparability between reading charts still exists, there is an increasing need for a worldwide standard in the form of a norm for diagnostic reading charts. Already, applied advancements such as digital print, which allow a calibration of the print sizes of reading charts in correctly progressing geometric proportions by using the actual height of a lower case "x" in millimeters (x-height), and psychophysically standardizing reading charts and their test items by applying modern statistical methods have significantly contributed to establishing a norm for reading charts. In 2020, a proposal of the British delegation was accepted by the International Organization for Standardization (ISO) group "Visual Optics and Optical Instruments," and a working group was established. Bearing in mind the efforts of the ISO with regard to an international norm, this review article is intended to (a) give an overview of the historical background and related normative approaches for diagnostic reading tests used in ophthalmology and optometry, (b) explain psychophysical and technical concerns, and (c) discuss the possibilities and limits of concepts that seem relevant to developing a modern standard for reading charts.

Trifocal intraocular lenses versus bifocal intraocular lenses after cataract extraction among participants with presbyopia

BACKGROUND

Presbyopia occurs when the lens of the eyes loses its elasticity leading to loss of accommodation. The lens may also progress to develop cataract, affecting visual acuity and contrast sensitivity. One option of care for individuals with presbyopia and cataract is the use of multifocal or extended depth of focus intraocular lens (IOL) after cataract surgery. Although trifocal and bifocal IOLs are designed to restore three and two focal points respectively, trifocal lens may be preferable because it restores near, intermediate, and far vision, and may also provide a greater range of useful vision and allow for greater spectacle independence in individuals with presbyopia.

OBJECTIVES

To assess the effectiveness and safety of implantation with trifocal versus bifocal IOLs during cataract surgery among people with presbyopia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2022, Issue 3); Ovid MEDLINE; Embase.com; PubMed; ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 31 March 2022.  SELECTION CRITERIA: We included randomized controlled trials that compared trifocal and bifocal IOLs among participants 30 years of age or older with presbyopia undergoing cataract surgery.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and graded the certainty of the body of evidence according to the GRADE classification.

MAIN RESULTS

We identified seven studies conducted in Europe and Turkey with a total of 331 participants. All included studies assessed visual acuity using a logarithm of the minimum angle of resolution (LogMAR chart). Of them, six (86%) studies assessed uncorrected distance visual acuity (the primary outcome of this review). Some studies also examined our secondary outcomes including uncorrected near, intermediate, and best-corrected distance visual acuity, as well as contrast sensitivity. Study characteristics All participants had bilateral cataracts with no pre-existing ocular pathologies or ocular surgery. Participants' mean age ranged from 55 to 74 years. Three studies reported on gender of participants, and they were mostly women. We assessed all of the included studies as being at unclear risk of bias for most domains. Two studies received financial support from manufacturers of lenses evaluated in this review, and at least one author of another study reported receiving payments for delivering lectures with lens manufacturers. Findings All studies compared trifocal versus bifocal IOL implantation on visual acuity outcomes measured on a LogMAR scale. At one year, trifocal IOL showed no evidence of effect on uncorrected distance visual acuity (mean difference (MD) 0.00, 95% confidence interval (CI) -0.04 to 0.04; I2 = 0%; 2 studies, 107 participants; low-certainty evidence) and uncorrected near visual acuity (MD 0.01, 95% CI -0.04 to 0.06; I2 = 0%; 2 studies, 107 participants; low-certainty evidence). Trifocal IOL implantation may improve uncorrected intermediate visual acuity at one year (MD -0.16, 95% CI -0.22 to -0.10; I2 = 0%; 2 studies, 107 participants; low-certainty evidence), but showed no evidence of effect on best-corrected distance visual acuity at one year (MD 0.00, 95% CI -0.03 to 0.04; I2 = 0%; 2 studies, 107 participants; low-certainty evidence). No study reported on contrast sensitivity or quality of life at one-year follow-up. Data from one study at three months suggest that contrast sensitivity did not differ between groups under photopic conditions, but may be worse in the trifocal group in one of the four frequencies under mesopic conditions (MD -0.19, 95% CI -0.33 to -0.05; 1 study; I2 = 0%, 25 participants; low-certainty evidence). One study examined vision-related quality of life using the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) at six months, and suggested no evidence of a difference between trifocal and bifocal IOLs (MD 1.41, 95% CI -1.78 to 4.60; 1 study, 40 participants; low-certainty evidence). Adverse events Adverse events reporting varied among studies. Of five studies reporting information on adverse events, two studies observed no intraoperative and postoperative complications or no posterior capsular opacification at six months. One study reported that glare and halos were similar to the preoperative measurements. One study reported that 4 (20%) and 10 (50%) participants had glare complaints at 6 months in trifocal and bifocal group, respectively (risk ratio 0.40, 95% CI 0.15 to 1.07; 40 participants). One study reported that four eyes (11.4%) in the bifocal group and three eyes (7.5%) in the trifocal group developed significant posterior capsular opacification requiring YAG capsulotomy at one year. The certainty of the evidence for adverse events was low.

AUTHORS' CONCLUSIONS

We found low-certainty of evidence that compared with bifocal IOL, implantation of trifocal IOL may improve uncorrected intermediate visual acuity at one year. However, there was no evidence of a difference between trifocal and bifocal IOL for uncorrected distance visual acuity, uncorrected near visual acuity, and best-corrected visual acuity at one year. Future research should include the comparison of both trifocal IOL and specific bifocal IOLs that correct intermediate visual acuity to evaluate important outcomes such as contrast sensitivity, quality of life, and vision-related adverse effects.

Comparative visual performance of diffractive bifocal and rotationally asymmetric refractive intraocular lenses

We compared the visual performance of a diffractive bifocal intraocular lens (IOL) with + 4.0 D near addition (ZMB00 [Johnson & Johnson Surgical Vision]) and a rotationally asymmetric refractive IOL with + 1.5 D near addition (LS-313 MF15 [Teleon Surgical BV]) 10 weeks after cataract patients' last surgery for bilateral ZMB00 or LS-313 MF15 implantation between 2011 and 2020, with the lenses of each eye implanted within 3 months of each other. The ZMB00 and LS-313 MF15 groups comprised 1326 eyes of 663 patients (age: 67.0 ± 7.8 years; females/males, 518/145) and 448 eyes of 224 patients (73.6 ± 7.0 years; females/males, 125/99), respectively. A linear mixed-effects model using data for both eyes, with strict adjustments for sex, age, subjective refraction spherical equivalent, subjective refraction cylinder, corneal astigmatism, axial length, corneal higher-order aberrations, and pupil diameter, ensured statistical validity. Compared to LS-313 MF15, ZMB00 achieved significantly superior uncorrected near visual acuity, reduced higher-order aberrations (ocular/internal, scaled to a 4-mm pupil; Wavefront_4_post_Ocular_Total Higher-Order Aberration/Third/Fourth/Trefoil/Coma/Tetrafoil/Spherical, Wavefront_4_post_Internal_Astigmatism/Total Higher-Order Aberration/Third/Trefoil/Coma/Tetrafoil/Spherical), and superior distance and near spectacle independence (p < 0.00068, Wald test). Contrast sensitivity, measured without (visual angle of the test target: 6.3°/4.0°/2.5°/1.6°/1.0°/0.7°) or with glare (4.0°/2.5°/1.6°/1.0°/0.7°), was significantly better in the LS-313 MF15 than the ZMB00 group (p < 0.00068, Wald test).

Visual Acuity, Defocus Curve, Reading Speed and Patient Satisfaction with a Combined Extended Depth of Focus Intraocular Lens and Multifocal Intraocular Lens Modality

Purpose

To evaluate the vision, defocus curve, reading speed and patient satisfaction after implantation of an extended depth of focus (EDOF) IOL in one eye and a diffractive multifocal in the fellow eye.

Setting

One clinical practice in the USA.

Design

Prospective unmasked non-randomized clinical trial.

Methods

Subjects presenting for routine cataract surgery interested in reducing their dependence on spectacles were enrolled. Study endpoints included uncorrected and distance-corrected binocular distance (4 m), intermediate (66 cm) and near (40 cm) visual acuity at 3 months. Additional endpoints included the residual refraction, spectacle independence, overall satisfaction with vision, visual symptoms, reading speed and defocus curve.

Results

With a best distance correction, 77% (30/39) of subjects had 20/25 or better VA at distance, intermediate and near and nearly all subjects had 20/32 or better VA at all three distances. Defocus curve results showed mean continuous vision of 20/25 or better from plano to −2.50 D. Nearly 80% (31/39) of subjects had 20/25 visual acuity from 0.00 D to −2.50 D. The critical print size was between 0.3 and 0.4 logMAR (20/40 to 20/50 Snellen Equivalent). Spectacle independence was 100% at distance, 95% at intermediate and approximately 70% at near. The percentage of subjects who were “not at all” or “slightly” bothered by visual disturbances ranged from 64% (16/25) for Halos to 88% (22/25) for Starbursts.

Conclusions

EDOF/bifocal IOL blended implantation results in at least 20/25 mean visual acuity from distance to near with good spectacle independence and low reports of severe visual disturbances.

Comparison of visual performance between monofocal and multifocal intraocular lenses of the same material and basic design

To compare the visual performance of a monofocal intraocular lens (IOL) (ZCB00) and a multifocal IOL (ZMB00) of the same material and basic design, we evaluated postoperative parameters at 10 weeks after the last surgery in cataract patients who underwent bilateral ZCB00 or ZMB00 implantation from December 13, 2010, to July 29, 2019, with the right and left lenses implanted within 3 months of each other. The study enrolled 2,230 eyes of 1,115 patients. The monofocal group comprised 904 eyes of 452 patients (72.3 ± 6.8 years; females/males, 268/184), and the multifocal group comprised 1,326 eyes of 663 patients (67.0 ± 7.8 years; females/males, 518/145). Contrast sensitivity (4.0/2.5/1.6/1.0/0.7 degrees), contrast sensitivity with glare (1.6/1.0/0.7 degrees), and the VFQ-25 score for driving at night were significantly better in the monofocal group (p < 0.00068, Wald test). Uncorrected intermediate/near visual acuity and near spectacle independence were significantly better in the multifocal group (p < 0.00068, Wald test). The two IOL groups had different characteristics in terms of contrast sensitivity, night-time driving, uncorrected intermediate/near visual acuity and near spectacle independence.

Comparison of reading performance with low add bifocal and extended depth of focus intraocular lenses implanted with mini-monovision

PURPOSE

To evaluate reading performance, preferred reading distance, and spectacle independence in patients implanted with a low add multifocal or an extended depth of focus (EDOF) intraocular lens (IOL) after phacoemulsification.

METHODS

In this prospective study, patients were randomized into two groups: the diffractive multifocal Tecnis + 2.75 D (ZKB00) IOL (Tecnis + 2.75 group; 15 patients) or the EDOF Tecnis Symfony (ZXR00) IOL (Symfony group; 14 patients) for bilateral implantation with mini-monovision. Reading performance parameters (reading acuity [RA], critical print size [CPS], and maximum reading speed [MRS]) were evaluated with MNREAD acuity charts at 40 cm, and preferred reading distances and spectacle independence for near activities were assessed preoperatively and at the postoperative 1st, 3rd, and 6th months.

RESULTS

At the postoperative 6th month, binocular logMAR UNVA and DCNVA were significantly better in the Symfony group than in the Tecnis + 2.75 group (UNVA: 0.15 ± 0.07 vs. 0.22 ± 0.08, p = 0.046; DCNVA: 0.21 ± 0.05 vs. 0.28 ± 0.07, p = 0.043; respectively). There was no significant difference in reading performance parameters between the groups; however, the Symfony group preferred significantly closer reading distance than the Tecnis + 2.75 group (42.00 ± 4.67 cm; 45.87 ± 5.32 cm, respectively, p = 0.030). At the postoperative 6th month, 14.3% and 26.7% of patients reported that they needed spectacles, rarely or occasionally, for near activities in the Symfony and Tecnis + 2.75 groups, respectively (p > 0.05).

CONCLUSIONS

When implanted with mini-monovision, although functional near visual acuity and a high degree of spectacle independence at near distances were achieved with both IOLs, patients implanted with the EDOF IOL preferred closer reading distance than those implanted with the low add diffractive multifocal IOL.

Trifocal intraocular lenses versus bifocal intraocular lenses after cataract extraction among participants with presbyopia

BACKGROUND

Presbyopia occurs when the lens of the eyes loses its elasticity leading to loss of accommodation. The lens may also progress to develop cataract, affecting visual acuity and contrast sensitivity. One option of care for individuals with presbyopia and cataract is the use of multifocal or extended depth of focus intraocular lens (IOL) after cataract surgery. Although trifocal and bifocal IOLs are designed to restore three and two focal points respectively, trifocal lens may be preferable because it restores near, intermediate, and far vision, and may also provide a greater range of useful vision and allow for greater spectacle independence in individuals with presbyopia.

OBJECTIVES

To assess the effectiveness and safety of implantation with trifocal versus bifocal IOLs during cataract surgery among participants with presbyopia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2019, Issue 9); Ovid MEDLINE; Embase.com; PubMed; ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 26 September 2019. We searched the reference lists of the retrieved articles and the abstracts from the Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO) for the years 2005 to 2015.

SELECTION CRITERIA

We included randomized controlled trials that compared trifocal and bifocal IOLs among participants 30 years or older with presbyopia undergoing cataract surgery.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

We identified five studies conducted in Europe with a total of 175 participants. All five studies assessed uncorrected distance visual acuity (primary outcome of the review), while some also examined our secondary outcomes including uncorrected near, intermediate, and best-corrected distance visual acuity, as well as contrast sensitivity. Study characteristics All participants had bilateral cataracts with no pre-existing ocular pathologies or ocular surgery. Participants' mean age ranged from 58 to 64 years. Only one study reported on gender of participants, and they were mostly women. We assessed all the included studies as being at unclear risk of bias for most domains. Two studies received financial support from manufacturers of lenses evaluated in this review, and at least one author of another study reported receiving payments for delivering lectures with lens manufacturers. Findings All studies compared trifocal versus bifocal IOL implantation on visual acuity outcomes measured on a LogMAR scale. At one year, trifocal IOL showed no evidence of effect on uncorrected distance visual acuity (mean difference (MD) 0.00, 95% confidence interval (CI) -0.04 to 0.04; I² = 0%; 2 studies, 107 participants; low-certainty evidence) and uncorrected near visual acuity (MD 0.01, 95% CI -0.04 to 0.06; I² = 0%; 2 studies, 107 participants; low-certainty evidence). Trifocal IOL implantation may improve uncorrected intermediate visual acuity at one year (MD -0.16, 95% CI -0.22 to -0.10; I²= 0%; 2 studies, 107 participants; low-certainty evidence), but showed no evidence of effect on best-corrected distance visual acuity at one year (MD 0.00, 95% CI -0.03 to 0.04; I²= 0%; 2 studies, 107 participants; low-certainty evidence). No study reported on contrast sensitivity or quality of life at one-year follow-up. Data from one study at three months suggest that contrast sensitivity did not differ between groups under photopic conditions, but may be worse in the trifocal group in one of the four frequencies under mesopic conditions (MD -0.19, 95% CI -0.33 to -0.05; 1 study; I² = 0%, 25 participants; low-certainty evidence). In two studies, the investigators observed that participants' satisfaction or spectacle independence may be higher in the trifocal group at six months, although another study found no evidence of a difference in participant satisfaction or spectacle independence between groups. Adverse events Adverse events reporting varied among studies. Two studies reported information on adverse events at one year. One study reported that participants showed no intraoperative or postoperative complications, while the other study reported that four eyes (11.4%) in the bifocal and three eyes (7.5%) in the trifocal group developed significant posterior capsular opacification requiring YAG capsulotomy. The certainty of the evidence was low.

AUTHORS' CONCLUSIONS

There is low-certainty of evidence that compared to bifocal IOL, implantation of trifocal IOL may improve uncorrected intermediate visual acuity at one year. However, there is no evidence of a difference between trifocal and bifocal IOL for uncorrected distance visual acuity, uncorrected near visual acuity, and best-corrected visual acuity at one year. Future research should include the comparison of both trifocal IOL and specific bifocal IOLs that correct intermediate visual acuity to evaluate important outcomes such as contrast sensitivity and quality of life.

Visual and Refractive Outcomes following Bilateral Implantation of Extended Range of Vision Intraocular Lens with Micromonovision

Purpose

To evaluate the outcomes following bilateral ERV intraocular lens implantation with micromonovision.

Methods

25 subjects underwent bilateral Tecnis Symfony IOL implantation with micromonovision. The dominant eye was targeted for emmetropia and the nondominant eye for myopia of -0.75 D. Uncorrected and corrected distance (UDVA, CDVA), intermediate (UIVA, CIVA), and near visual acuity (UNVA, DCNVA); reading performance; defocus curve; and contrast sensitivity were studied. Follow-ups were conducted at 1 week and 1 and 6 months postoperatively.

Results

At 6 months postoperatively, the mean binocular UDVA, CDVA, UNVA, and DCNVA were -0.036 ± 0.09, -0.108 ± 0.07, 0.152 ± 0.11, and 0.216 ± 0.10 logMAR, respectively. Binocular UIVA and DCIVA were 0.048 ± 0.09 and 0.104 ± 0.08 logMAR, respectively, at 60 cm and -0.044 ± 0.09 and 0.012 ± 0.09 logMAR, respectively, at 80 cm. All patients had ≥0.2 logMAR UDVA and UNVA. Reading acuity and reading speeds showed improvement over time. Between defocus range of -2.50 and +1.00 D, the visual acuity remained ≥0.2 logMAR. Contrast sensitivity scores were within the normal range. 4 patients used reading glasses for very fine print.

Conclusion

Bilateral ERV IOL implantation leads to excellent outcomes for far and intermediate vision, satisfactory outcomes for near vision, and good tolerance to micromonovision at the end of the 6 months. This trial is registered with CTRI/2015/10/006246.

Reading charts in ophthalmology

A new generation of logarithmic reading charts has sparked interest in standardized reading performance analyses. Such reading charts have been developed according to the standards of the International Council of Ophthalmology. The print size progression in these calibrated charts is in accordance with the mathematical background of EN ISO 8596. These reading charts are: the Bailey–Lovie Word Reading Chart, the Colenbrander English Continuous Text Near Vision Cards, the Oculus Reading Probe II, the MNREAD Charts, the SKread Charts, and the RADNER Reading Charts. The test items used for these reading charts differ among the charts and are standardized to various extents. The Bailey–Lovie Charts, MNREAD Charts, SKread Charts, and RADNER Charts are also meant to measure reading speed and allow determination of further reading parameters such as reading acuity, reading speed based on reading acuity, critical print size, reading score, and logMAR/logRAD ratio. Such calibrated reading charts have already provided valuable insights into the reading performance of patients in many research studies. They are available in many languages and thus facilitate international communication about near visual performance. In the present review article, the backgrounds of these modern reading charts are presented, and their different levels of test-item standardization are discussed. Clinical research studies are mentioned, and a discussion about the immoderately high number of reading acuity notations is included. Using the logReading Acuity Determination ([logRAD] = reading acuity equivalent of logMAR) measure for research purposes would give reading acuity its own identity as a standardized reading parameter in ophthalmology.

Multifocal versus monofocal intraocular lenses after cataract extraction

BACKGROUND

Good unaided distance visual acuity (VA) is now a realistic expectation following cataract surgery and intraocular lens (IOL) implantation. Near vision, however, still requires additional refractive power, usually in the form of reading glasses. Multiple optic (multifocal) IOLs are available which claim to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal IOLs.

OBJECTIVES

To assess the visual effects of multifocal IOLs in comparison with the current standard treatment of monofocal lens implantation.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2016), Embase (January 1980 to June 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 June 2016.

SELECTION CRITERIA

All randomised controlled trials comparing a multifocal IOL of any type with a monofocal IOL as control were included. Both unilateral and bilateral implantation trials were included. We also considered trials comparing multifocal IOLs with "monovision" whereby one eye is corrected for distance vision and one eye corrected for near vision.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We assessed the 'certainty' of the evidence using GRADE.

MAIN RESULTS

We found 20 eligible trials that enrolled 2230 people with data available on 2061 people (3194 eyes). These trials were conducted in Europe (13), China (three), USA (one), Middle East (one), India (one) and one multicentre study in Europe and the USA. Most of these trials compared multifocal with monofocal lenses; two trials compared multifocal lenses with monovision. There was considerable variety in the make and model of lenses implanted. Overall we considered the trials at risk of performance and detection bias because it was difficult to mask participants and outcome assessors. It was also difficult to assess the role of reporting bias.There was moderate-certainty evidence that the distance acuity achieved with multifocal lenses was not different to that achieved with monofocal lenses (unaided VA worse than 6/6: pooled RR 0.96, 95% confidence interval (CI) 0.89 to 1.03; eyes = 682; studies = 8). People receiving multifocal lenses may achieve better near vision (RR for unaided near VA worse than J3/J4 was 0.20, 95% CI 0.07 to 0.58; eyes = 782; studies = 8). We judged this to be low-certainty evidence because of risk of bias in the included studies and high heterogeneity (I² = 93%) although all included studies favoured multifocal lenses with respect to this outcome.People receiving multifocal lenses may be less spectacle dependent (RR 0.63, 95% CI 0.55 to 0.73; eyes = 1000; studies = 10). We judged this to be low-certainty evidence because of risk of bias and evidence of publication bias (skewed funnel plot). There was also high heterogeneity (I² = 67%) but all studies favoured multifocal lenses. We did not additionally downgrade for this.Adverse subjective visual phenomena were more prevalent and more troublesome in participants with a multifocal IOL compared with monofocals (RR for glare 1.41, 95% CI 1.03 to 1.93; eyes = 544; studies = 7, low-certainty evidence and RR for haloes 3.58, 95% CI 1.99 to 6.46; eyes = 662; studies = 7; moderate-certainty evidence).Two studies compared multifocal lenses with monovision. There was no evidence for any important differences in distance VA between the groups (mean difference (MD) 0.02 logMAR, 95% CI -0.02 to 0.06; eyes = 186; studies = 1), unaided intermediate VA (MD 0.07 logMAR, 95% CI 0.04 to 0.10; eyes = 181; studies = 1) and unaided near VA (MD -0.04, 95% CI -0.08 to 0.00; eyes = 186; studies = 1) compared with people receiving monovision. People receiving multifocal lenses were less likely to be spectacle dependent (RR 0.40, 95% CI 0.30 to 0.53; eyes = 262; studies = 2) but more likely to report problems with glare (RR 1.41, 95% CI 1.14 to 1.73; eyes = 187; studies = 1) compared with people receiving monovision. In one study, the investigators noted that more people in the multifocal group underwent IOL exchange in the first year after surgery (6 participants with multifocal vs 0 participants with monovision).

AUTHORS' CONCLUSIONS

Multifocal IOLs are effective at improving near vision relative to monofocal IOLs although there is uncertainty as to the size of the effect. Whether that improvement outweighs the adverse effects of multifocal IOLs, such as glare and haloes, will vary between people. Motivation to achieve spectacle independence is likely to be the deciding factor.

Integrating a novel concept of sentence optotypes into the RADNER Reading Charts

PURPOSE

To add a new set of 24 sentence optotypes to the German version of the RADNER reading charts and to investigate whether sentences constructed based upon an optimised concept of sentence optotypes can be used together with the original 38 sentences.

METHODS

Twenty-eight optimised sentence optotypes were constructed based upon the concept of sentence optotypes as established for the RADNER Reading Charts, with words having the same number of characters and syllables being placed in the same positions. The best comparable sentences were statistically selected in 30 volunteers. Reading speed and the number of errors were determined. Validity was analysed in comparison to a 111-word long standardised paragraph and 7 of the 38 original sentence optotypes.

RESULTS

The mean reading speed obtained with the 28 sentences was 192.30±26.69 words per minute (wpm), as compared with 192.47±25.32 wpm for the 7 original sentence optotypes and 165.28±20.82 wpm for the long paragraph; 24 of the 28 optimised sentences met our selection criteria for reading speed/time (mean reading speed: 192.41±26.58). The mean number of reading errors was 0.10±0.30. The correlation between the 24 optimised sentence optotypes and the long paragraph was r=0.90. Reliability analyses yielded an overall Cronbach's α coefficient of 0.992.

CONCLUSION

The 24 new sentence optotypes can be integrated into the existing set of 38 original sentences. Since all the statistical results obtained were similar to those of the original sentences, the best possible reliability had apparently already been achieved with the original sentence optotypes.

Near vision examination in presbyopia patients: Do we need good homologated near vision charts?

Presbyopia correction is mainly concerned with the goal of regaining an uncorrected reading performance. Since historic reading charts do not provide a unique standard that is applicable for the analysis of clinical and scientific reading performance, new standardized reading charts have been developed, in order to provide reading performance analyses analogous to modern single-optotype distance acuity measurements: the Bailey-Lovie Word Reading Chart, the Colenbrander English Continuous Text Near Vision Cards, the MNREAD Charts, and the RADNER Reading Charts. The last three are also meant to measure reading speed, thus allowing detailed analysis of the reading capabilities of the patient’s functional vision. Furthermore, these reading charts can be declared homologated, based on the standards that were published for reading charts by the Visual Function Committee of the International Council of Ophthalmology (ICO) in 1988. Many research studies have shown that by analyzing the reading performance with homologated reading charts, valuable insight into the reading performance of patients suffering from various diseases can be obtained. These reading charts have also been successfully used in presbyopia research. It therefore seems evident that homologated, standardized reading charts facilitate not only research concerning functional vision in many fields of ophthalmology but also international communication about near visual performance. Homologated reading charts are available in almost all languages and have become a valuable tool in analyzing reading performance. We argue in this review that homologated reading charts are clearly a necessity for presbyopia research.

Clinical outcomes and optical performance of four differentmultifocal intraocular lenses

BACKGROUND/AIM

The purpose of the present study was to evaluate clinical outcomes and optical performance of 4 different multifocal intraocular lenses (IOLs).

MATERIALS AND METHODS

Ninety eyes of 51 patients who received Reviol MFM 611, Reviol MFM 625, Acri.LISA, and ReSTOR SN6AD3 multifocal IOLs after cataract surgery were retrospectively evaluated. The patients were similar in terms of age, sex, cataract hardness and axial length. The mean outcome measures were uncorrected and corrected distance visual acuity (UDVA, CDVA), distance-corrected intermediate and near visual acuity (DCIVA, DCNVA), intra or postoperative complications, and contrast sensitivity (CS) results under mesopic conditions. The mean follow up period was 10.5 months (range: 6-12 months).

RESULTS

All cases were within ± 0.75 D of emmetropia. Postoperative increase in UDVA and DCNVA was statistically significant in all groups. The Acri.LISA group showed slightly lower DCIVA compared with the other IOLs. CS was clinically similar between the groups. None of the patients developed any early or late postoperative complication or neuroadaptation problem, which necessitated explantation of the lens.

CONCLUSION

All four multifocal lens designs provided satisfactory visual functions and CS results in patients who fulfilled the criteria for multifocal lens implantation.

IURead: a new computer-based reading test

PURPOSE

To develop a computer-based single sentence reading test especially designed for clinical research enabling multiple repeat trials without reusing the same sentences.

METHODS

We initially developed 422 sentences, with an average of 60 characters and 12 words. Presentation controls were improved by employing computer-based testing and the oral reading was recorded by visual inspection of digital audio recordings. Variability in reading speed of normally sighted adults between sentences, between charts, between subjects, between formats, and between display devices was quantified. The impact of display size and pixel resolution on test geometry was assessed, and the impact of reduced retinal image quality and retinal illuminance were compared for reading and standard letter acuities. Eleven visually normal subjects (age: 18-60 years) participated in this study.

RESULTS

Stopwatch timing of sentences reliably underestimated reading times by about 0.3 s, and exhibited coefficients of repeatability 17 times larger than those estimated from visual inspection of digital recordings. A slight relaxing of the lexical content constraints had no effect on reading speed; neither did sentence format (single vs three lines) or display size or distance. Within subject standard deviations of reading speed for different sentences were small (between 6% and 9% of the mean speed) requiring only small samples sizes to achieve typical statistical reliability and power when comparing conditions within individual subjects. The greater variability associated with stopwatch timing necessitates larger sample sizes. As defocus and light level were varied, reading acuity and standard letter acuity were highly correlated (r(2)  = 0.99), and reading acuity was slightly better.

DISCUSSION

A computer-based IURead reading test provides a useful reading speed and reading acuity tool for clinical research involving multiple conditions and repeat testing of individual subjects. Ready to use IURead files for use with a computer, tablet or cell phone can be downloaded from our lab website (https://www.opt.indiana.edu/Bradley/Downloads.aspx).

Measurement properties of continuous text reading performance tests

PURPOSE

Measurement properties of tests to assess reading acuity or reading performance have not been extensively evaluated. This study aims to provide an overview of the literature on available continuous text reading tests and their measurement properties.

METHODS

A literature search was performed in PubMed, Embase and PsycInfo. Subsequently, information on design and content of reading tests, study design and measurement properties were extracted using consensus-based standards for selection of health measurement instruments. Quality of studies, reading tests and measurement properties were systematically assessed using pre-specified criteria.

RESULTS

From 2334 identified articles, 20 relevant articles were found on measurement properties of three reading tests in various languages: IReST, MNread Reading Test and Radner Reading Charts. All three reading tests scored high on content validity. Reproducibility studies (repeated measurements between different testing sessions) of the IReST and MNread of commercially available reading tests in different languages were missing. The IReST scored best on inter-language comparison, the MNread scored well in repeatability studies (repeated measurements under the same conditions) and the Radner showed good reproducibility in studies.

CONCLUSIONS

Although in daily practice there are other continuous text reading tests available meeting the criteria of this review, measurement properties were described in scientific studies for only three of them. Of the few available studies, the quality and content of study design and methodology used varied. For testing existing reading tests and the development of new ones, for example in other languages, we make several recommendations, including careful description of patient characteristics, use of objective and subjective lighting levels, good control of working distance, documentation of the number of raters and their training, careful documentation of scoring rules and the use of Bland-Altman analyses or similar for reproducibility and repeatability studies.

English sentence optotypes for measuring reading acuity and speed--the English version of the Radner Reading Charts

PURPOSE

To develop 28 short sentence optotypes for the English version of the Radner Reading Charts that are as comparable as possible in number and length of words, as well as in difficulty and syntactical construction.

METHODS

Thirty-four English sentences were constructed following the method used for other Radner Reading Charts to obtain "sentence optotypes" with comparable structure and the same lexical and grammatical difficulty. Best comparable sentences were statistically selected and standardized in 50 volunteers. Reading speed and the number of errors were determined. Validity was analyzed with a 124-word long 4th-grade paragraph of the Florida Comprehensive Assessment Test®. Computerized measurements of reading parameters were performed with the RADNER Reading Device (RAD-RD©; in conjunction with a PC and microphone).

RESULTS

The mean reading speed obtained with the 28 selected short sentences was 201.53 ± 35.88 words per minute (wpm), as compared to 215.01 ± 30.37 wpm for the long paragraph. The mean reading times were 4.30 ± 0.79 s and 35.26 ± 4.85 s, respectively. The mean number of reading errors was 0.11 ± 0.34. The correlation between the short sentences and the long paragraph was high (r = 0.76; p < 0.05; n = 50). Reliability analyses yielded an overall Cronbach's alpha coefficient of 0.9743.

CONCLUSION

The present study indicates that the 28 selected English sentence optotypes are comparable in terms of both lexical difficulty as well as in reading length, and it demonstrates the validity and reliability of such sentences as test items for determining reading parameters such as reading acuity and speed.

Bilateral reading performance of 4 multifocal intraocular lens models and a monofocal intraocular lens under bright lighting conditions

PURPOSE

To compare changes in reading performance parameters after implantation of 4 multifocal intraocular lens (IOL) models and a monofocal IOL.

SETTING

Department of Ophthalmology, Paracelsus Medical University, Salzburg, Austria.

DESIGN

Prospective randomized controlled clinical trial.

METHODS

Patients with bilateral cataract without additional ocular pathology were scheduled for bilateral implantation of Acri.Smart 48S monofocal, Acrysof Restor SN6AD3 apodized multifocal, AT LISA 366D diffractive multifocal, Tecnis ZMA00 diffractive multifocal, or Rezoom refractive multifocal IOLs. Bilateral corrected and uncorrected reading acuity, reading distance, mean and maximum reading speeds, and smallest log-scaled print size of a Radner reading chart were evaluated under bright lighting conditions (500 lux) using the Salzburg Reading Desk. Pupil size was not measured throughout the trial. The minimum follow-up was 12 months.

RESULTS

The diffractive multifocal groups had significantly better uncorrected reading acuity and uncorrected smallest print size than the monofocal and refractive multifocal groups 1, 6, and 12 months postoperatively. The diffractive IOL groups had comparable uncorrected reading distance of approximately 32 cm, which was larger in the monofocal group (38.9 ± 8.4 cm) and refractive multifocal group (37.1 ± 7.3 cm) at the last visit. Patients with diffractive IOLs could read print sizes of approximately 0.74 to 0.87 mm, which was much better than in the monofocal and refractive multifocal groups. The diffractive AT LISA IOL provided the best reading speed values (mean and maximum, corrected and uncorrected).

CONCLUSION

Multifocal IOLs with a diffractive component provided good reading performance that was significantly better than that obtained with a refractive multifocal or monofocal IOL.

FINANCIAL DISCLOSURE

Drs. Grabner and Dexl were patent owners of the Salzburg Reading Desk technology (now owned by SRD-Vision, LLC). No other author has a financial or proprietary interest in any material or method mentioned.

Multifocal versus monofocal intraocular lenses after cataract extraction

BACKGROUND

Good unaided distance visual acuity is now a realistic expectation following cataract surgery and intraocular lens (IOL) implantation. Near vision, however, still requires additional refractive power, usually in the form of reading glasses. Multiple optic (multifocal) IOLs are available which claim to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal IOLs.

OBJECTIVES

The objective of this review was to assess the effects of multifocal IOLs, including effects on visual acuity, subjective visual satisfaction, spectacle dependence, glare and contrast sensitivity, compared to standard monofocal lenses in people undergoing cataract surgery.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 2), MEDLINE (January 1946 to March 2012), EMBASE (January 1980 to March 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 6 March 2012. We searched the reference lists of relevant articles and contacted investigators of included studies and manufacturers of multifocal IOLs for information about additional published and unpublished studies.

SELECTION CRITERIA

All randomised controlled trials comparing a multifocal IOL of any type with a monofocal IOL as control were included. Both unilateral and bilateral implantation trials were included.

DATA COLLECTION AND ANALYSIS

Two authors collected data and assessed trial quality. Where possible, we pooled data from the individual studies using a random-effects model, otherwise we tabulated data.

MAIN RESULTS

Sixteen completed trials (1608 participants) and two ongoing trials were identified. All included trials compared multifocal and monofocal lenses but there was considerable variety in the make and model of lenses implanted. Overall we considered the trials at risk of performance and detection bias because it was difficult to mask patients and outcome assessors. It was also difficult to assess the role of reporting bias. There was moderate quality evidence that similar distance acuity is achieved with both types of lenses (pooled risk ratio (RR) for unaided visual acuity worse than 6/6: 0.98, 95% confidence interval (CI) 0.91 to 1.05). There was also evidence that people with multifocal lenses had better near vision but methodological and statistical heterogeneity meant that we did not calculate a pooled estimate for effect on near vision. Total freedom from use of glasses was achieved more frequently with multifocal than monofocal IOLs. Adverse subjective visual phenomena, particularly haloes, or rings around lights, were more prevalent and more troublesome in participants with the multifocal IOL and there was evidence of reduced contrast sensitivity with the multifocal lenses.

AUTHORS' CONCLUSIONS

Multifocal IOLs are effective at improving near vision relative to monofocal IOLs. Whether that improvement outweighs the adverse effects of multifocal IOLs will vary between patients. Motivation to achieve spectacle independence is likely to be the deciding factor.

Pseudophakic monovision using monofocal and multifocal intraocular lenses: hybrid monovision

PURPOSE

To evaluate the visual function after bilateral cataract surgery performed with a new technique (hybrid monovision) that uses a monofocal intraocular lens (IOL) and a diffractive multifocal IOL.

SETTING

Department of Ophthalmology, Kitasato University Hospital, Kanagawa, Japan.

DESIGN

Case series.

METHODS

Hybrid monovision was achieved by implanting a monofocal IOL (AQ310Ai) in the dominant eye and a diffractive multifocal IOL (Tecnis ZM900) in the nondominant contralateral eye. The target refraction was emmetropia in both eyes. Visual acuity at various distances, contrast sensitivity, near stereopsis, reading ability, and the degree of patient satisfaction were measured.

RESULTS

The study enrolled 32 patients with a mean age of 61.2 years ± 14.7 (SD). At all distances, the mean binocular visual acuity was better than 0.1 logMAR. Binocular contrast sensitivity was better than monocular vision in the eye with the diffractive multifocal IOL. Near stereopsis within normal range was maintained in 62.5% of patients. Of the patients, 18.8% reported spectacle dependence. With binocular vision, no patients reported waxy vision (ie, as though they were looking through water).

CONCLUSION

Hybrid monovision may be an effective approach for managing loss of accommodation after cataract surgery and may be the method of choice in cases of waxy vision caused by bilateral multifocal IOL implantation.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

US FDA clinical trial of the Tetraflex potentially accommodating IOL: comparison to concurrent age-matched monofocal controls

PURPOSE

To assess the efficacy of the Tetraflex (Lenstec Inc) intraocular lens (IOL) to provide enhanced near reading ability and spectacle independence relative to a monofocal control IOL in bilaterally implanted eyes tested binocularly.

METHODS

A prospective, age-matched, non-randomized US Food and Drug Administration clinical trial of 255 Tetraflex and 101 monofocal IOL control patients was performed. To date, 239 Tetraflex and 96 control patients were examined at 12 months postoperatively.

RESULTS

At 12 months postoperative, the Tetraflex patients read better than the controls at print sizes of 20/80 (P=.04), 20/63 (P=.01), 20/50 (P<.001), 20/40 (P=.001), 20/32 (P<.001), and 20/25 (P=.001). The proportion of patients reading at a speed of ≥80 words per minute was significantly higher with the Tetraflex IOL (P=.003). Ninety-six percent of Tetraflex patients reported never wearing glasses for distance compared with 80% of control patients (P<.001). Seventy-five percent of the Tetraflex patients reported near spectacle wear either never or only occasionally for small print and/or dim light (21% never) compared with 46% of control patients (P<.001) (9% never). Near add power requirement for corrected near visual acuity was less in the Tetraflex group (P<.001); 28% of Tetraflex patients required ≤1.25 diopters of near add, compared to only 7% of control patients. Spectacle independence, as measured by the proportion of patients with uncorrected distance visual acuity of 20/25 or better and various degrees of uncorrected near visual acuity, was also significantly better (P<.001) as was distance-corrected near visual acuity (P<.001).

CONCLUSIONS

The results support the efficacy of the Tetraflex IOL to provide enhanced near reading ability and spectacle independence relative to a monofocal IOL control.

All-distance visual acuity in eyes with a nontinted or a yellow-tinted diffractive multifocal intraocular lens

PURPOSE

To compare all-distance visual acuity (VA) between eyes with a nontinted diffractive multifocal intraocular lens (IOL), a yellow-tinted multifocal IOL, and a nontinted monofocal IOL.

METHODS

Thirty-four patients underwent bilateral implantation of a nontinted multifocal IOL (Alcon ReSTOR), 30 received a yellow-tinted multifocal IOL (ReSTOR Natural), and 17 a monofocal IOL. All-distance VA was measured with an all-distance vision tester at 12 months postoperatively. The relationships between pupillary diameter and IOL decentration and tilt with VA were determined.

RESULTS

Both uncorrected and best distance-corrected near VA in the multifocal groups were significantly better than those in the monofocal group, whereas no significant differences were found in far-to-intermediate VAs. There was no significant difference in all-distance VA between the nontinted and yellow-tinted multifocal groups. In the multifocal groups, a larger pupillary diameter was associated with better near VA, whereas there was no correlation between VA and IOL decentration and tilt.

CONCLUSIONS

Near VA with a diffractive multifocal IOL was better than that with a monofocal IOL, although far-to-intermediate VAs were similar. All-distance VA with the nontinted multifocal IOL was similar to that with the yellow-tinted multifocal IOL. Larger pupillary diameter was associated with better near VA with the multifocal IOL.

One-year outcomes with new-generation multifocal intraocular lenses

PURPOSE

To compare new-generation multifocal intraocular lenses (IOLs) with monofocal IOLs.

DESIGN

Randomized prospective clinical trial.

PARTICIPANTS

Sixty-two consecutive patients with cataract, seen between January of 2005 and January of 2006 at the Department of Ophthalmology of Palermo University Hospital in Italy, were bilaterally implanted with monofocal (AR 40, Advanced Medical Optics [AMO], Santa Ana, CA; 15 patients), multifocal refractive (Array SA40N, AMO; 16 patients), multifocal refractive (ReZoom, AMO; 15 patients), or multifocal diffractive pupil-independent (Tecnis ZM900, AMO; 16 patients) IOLs.

INTERVENTION

Bimanual phacoemulsification.

MAIN OUTCOME MEASURES

Primary outcomes were far, near, and intermediate visual acuity of the 4 IOL-implanted groups. Secondary outcomes were defocusing curves, contrast sensitivity, patients' quality of life (7-item visual function questionnaire [VF-7], halos and glare presence, overall satisfaction), and spectacle independence. Snellen visual acuity was measured as uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), uncorrected near visual acuity (UCNVA), best distance corrected near visual acuity (BDCNVA), best corrected near visual acuity (BCNVA), uncorrected intermediate visual acuity (UCIVA), and best distance corrected intermediate visual acuity (BDCIVA).

RESULTS

UCNVA was 20/50 in the monofocal IOL group, compared with 20/32 or better in the multifocal IOL groups (P<0.0005). The monofocal IOL group exhibited a lower BDCNVA than the multifocal IOL groups (P<0.0005). The diffractive multifocal IOL group performed better than either refractive group (P = 0.007). UCIVA was significantly different (P = 0.001) among the groups: monofocal (AR 40) 20/32; multifocal refractive (Array SA40N) 20/30; multifocal refractive (ReZoom) 20/25; and multifocal diffractive (Tecnis ZM900) 20/30. Defocusing curves with -3.00 diopter lens exhibited a better trend in the diffractive group. The refractive multifocal IOL groups exhibited lower contrast sensitivities at 3 cycles/degree (P = 0.038). The VF-7 mean score was significantly lower in the monofocal than the multifocal IOL groups (P = 0.002). Night halos were more common in the refractive groups (P<0.01). Spectacle independence was 20% in the monofocal IOL group, 43.7% and 53.3% in the refractive multifocal IOL groups, and 87.5% in the diffractive multifocal IOL group (P<0.05).

CONCLUSIONS

Multifocal IOLs provide a greater depth of focus and higher patient satisfaction, and make intermediate and near visual tasks easier than do monofocal lenses. New-generation, diffractive, pupil-independent multifocal IOLs provide better near vision, equivalent intermediate vision, less unwanted photic phenomena, and greater spectacle independence than either monofocal or refractive multifocal IOLs.

Visual function with bilateral implantation of monofocal and multifocal intraocular lenses: a prospective, randomized, controlled clinical trial

PURPOSE

To evaluate visual function of three types of multifocal intraocular lenses (IOLs) and one monofocal IOL (as the control group) after cataract surgery.

METHODS

One hundred fourteen patients participated in a prospective, randomized, controlled clinical study and received monofocal Tecnis Z9000 (AMO) (n = 24, 48 eyes); symmetric diffractive multifocal Tecnis ZM900 (AMO) (n = 26, 52 eyes); zonal refractive multifocal ReZoom (AMO) (n = 32, 64 eyes); and asymmetric diffractive multifocal TwinSet (Acri.Tec) (n = 32, 64 eyes) IOLs.

RESULTS

Mean binocular distance best spectacle-corrected visual acuity (BSCVA) (logMAR) was 0.05 for controls, 0.08 for ZM900, 0.07 for ReZoom, and 0.11 for TwinSet, with mean binocular distance BSCVA at near of 0.49, 0.06, 0.22, and 0.11, respectively. Mean contrast sensitivity was better for the monofocal IOL group than for the multifocal IOLs. Patients assigned to TwinSet had less favorable contrast sensitivity scores. Patients with monofocal IOLs had more frequently recommended near addition (74%) than those with multifocal IOLs. Patients with refractive ReZoom had also recommended near addition more frequently than the two diffractive groups. The percentage of dysphotopsia phenomena was 81% in patients with diffractive multifocal ZM900 compared with 48% in patients with monofocal IOLs, 53% with refractive ReZoom, and 47% with diffractive TwinSet.

CONCLUSIONS

The monofocal IOL showed better visual function and lesser photic phenomena than multifocal IOLs but patients were spectacle dependent. ReZoom provided better distance BSCVA than the TwinSet diffractive model. Patients with Tecnis and TwinSet diffractive multifocal IOLs were more spectacle independent than patients with ReZoom. Patients with TwinSet had the worst visual function. Patients implanted with the Tecnis diffractive ZM900 were those reporting more photic phenomena.

Functional outcomes after implantation of Tecnis ZM900 and Array SA40 multifocal intraocular lenses

PURPOSE

To evaluate the functional outcome after implantation of the Tecnis ZM900 multifocal intraocular lens (IOL) (AMO) and the Array SA40 multifocal IOL (AMO).

SETTING

Department of Ophthalmology, Bundesknappschaft s Hospital, Sulzbach, and the Department of Ophthalmology, Marienhospital, Aachen, Germany.

METHODS

In a prospective comparative 2-center trial, Tecnis ZM900 and the Array SA40 multifocal IOLs were bilaterally implanted in 50 patients (50 eyes Tecnis, 50 eyes Array) by 1 surgeon at each center. The following parameters were assessed 30 to 60 days and 120 to 180 days after surgery in both eyes: refraction, pupil size, uncorrected and best corrected visual acuities for distance and near at different contrast levels, and photopic and mesopic contrast sensitivity at different spatial frequencies. Patient satisfaction (spectacle independence, photic phenomena, overall satisfaction) was assessed by a questionnaire.

RESULTS

The main differences between the 2 multifocal IOLs were the better uncorrected near visual acuity (P<.001), distance-corrected near visual acuity (P<.001), the mesopic contrast sensitivity at high spatial frequencies (P<.05) as well as greater independence from spectacles in patients with the Tecnis multifocal IOL, resulting in higher levels of patient satisfaction.

CONCLUSION

The aspherical diffractive Tecnis multifocal IOL gave better outcomes than the Array multifocal IOL.