Impact of differences between eyes on binocular measures of vision in patients with cataracts

Stereopsis Following Implantation of Presbyopia-Correcting Intraocular Lenses: A Narrative Review

Recent advancements in cataract surgery have broadened its scope from mere vision restoration to include correction of refractive errors and presbyopia. This evolution has introduced multifocal and extended depth-of-focus (EDOF) intraocular lenses (IOLs), allowing enhanced vision across multiple distances. However, the influence of these advanced IOLs on stereopsis remains controversial. Factors influencing stereopsis after surgery include visual acuity, interocular differences, residual astigmatism, and the type of IOL, etc. Binocular vision integration and neuroadaptation further affect stereopsis, especially in cases of presbyopia-correcting IOLs. It is widely acknowledged that bilateral implantation of presbyopia-correcting IOLs yield superior stereopsis compared to unilateral implantation. However, there remains no consensus on whether binocular implantation of multifocal or monofocal IOLs provides superior stereopsis. Most studies suggest no significant difference in stereopsis between these two types of implants. Among different types of multifocal IOLs, refractive multifocal IOLs may offer better stereopsis than diffractive multifocal IOLs when implanted bilaterally. Emerging EDOF and hybrid multifocal-EDOF IOLs also demonstrate promising postoperative stereopsis. Additionally, a mix-and-match strategy with different types of IOLs implanted in each eye may result in interocular differences in visual acuity at certain distances, potentially affecting stereopsis. Nevertheless, with appropriate selection, most patients can achieve satisfactory postoperative stereopsis. This review synthesizes current literature on the effects of presbyopia-correcting IOLs on postoperative stereopsis recovery following cataract surgery. Studies on stereopsis outcomes with different IOLs have yielded mixed results, urging further investigation for optimized surgical strategies and patient outcomes.

Immediate Sequential Bilateral Cataract Surgery in Patients with Bilateral Visually Significant Cataracts

Purpose

To report our experience of performing immediate sequential bilateral cataract surgery (ISBCS) in patients with visually significant cataracts and reduced preoperative corrected distance visual acuity (CDVA).

Methods

Data of patients who underwent ISBCS for visually significant cataracts and had preoperative CDVA ≤20/32 (≤0.2 logMAR) in each eye were retrospectively reviewed. Refractive and visual outcomes were evaluated for the last available postoperative visit. Intraoperative and serious postoperative adverse events occurring within the first three months of surgery were reviewed.

Results

A total of 1335 patients (2670 eyes) were included in the analysis, with a mean age of 71.9 ± 9.5 years. On the last visit, 50.2% and 89.1% of eyes achieved uncorrected distance visual acuity (UDVA) ≥20/20 (0.0 logMAR) and ≥20/32 (0.2 logMAR), respectively. Of all eyes, 83.8% were within ±0.50D, and 96.4% were within ±1.00 D of emmetropia. Ten patients had postoperative bilateral ametropia of more than 1.00D in each eye, but eight of them still achieved binocular UDVA ≥20/40. Intraoperative events occurred in 14 eyes of 13 patients (per-eye incidence: 0.524% or 1 in 191 eyes). A total of 86 postoperative adverse events occurred in 80 eyes of 53 patients (per-eye incidence 2.996% or 1 in 33 eyes), of which cystoid macular edema was the most common. Only three eyes had CDVA reduced by more than two Snellen lines compared to preoperative CDVA, two of which were not related to cataract surgery. There was no patient with bilateral CDVA loss.

Conclusion

In our cohort of patients with visually significant cataracts, ISBCS resulted in good refractive predictability and a low incidence of serious adverse events.

Changes in driving performance after first and second eye cataract surgery: A driving simulator study

INTRODUCTION

This study investigated the separate impact of first eye and second eye cataract surgery on driving performance, as measured on a driving simulator.

METHOD

Forty-four older drivers with bilateral cataract aged 55+ years, awaiting first eye cataract surgery participated in a prospective cohort study. They completed a questionnaire, visual tests and a driving simulator assessment at three time points: before first eye, after first eye, and after second eye cataract surgery. Generalized Estimating Equation Poisson or linear regression models were undertaken to examine the change in four driving outcomes of interest after adjusting for cataract surgery and other potential confounders.

RESULTS

The rate of crashes/near crashes decreased significantly by 36% (incidence rate ratio (IRR) 0.64, 95% CI 0.47-0.88, p = 0.01) after first eye surgery and 47% (IRR 0.53, 95% CI 0.35-0.78, p < 0.001) after second eye surgery, compared to before first eye cataract surgery, after accounting for confounders. The rate of crashes/near crashes also decreased with better contrast sensitivity (IRR 0.69, 95% CI 0.48-0.90, p = 0.041). A separate model found that time spent speeding 10 kilometers per hour or more over the limit after second eye surgery was significantly less (0.14 min, p = 0.002), compared to before first eye surgery, after accounting for confounders. As contrast sensitivity improved, the duration of speeding also decreased significantly by 0.46 min (p = 0.038). There were no statistically significant changes in lane excursions or speed variation. Practical applications: The findings highlight the importance of timely first and second eye cataract surgery to ensure driver safety, especially as older drivers wait for second eye cataract surgery. It also provides further evidence that contrast sensitivity is probably a better predictor of driving ability in older drivers with cataract than visual acuity, the measure on which driver licensing requirements are currently based, and should also be used when assessing fitness to drive.

Binocular Visual Function in a Pre-Presbyopic Patient with Uniocular Cataract Undergoing Cataract Surgery with a Multifocal Intraocular Lens

Background/Aim

An increasing number of pre-presbyopic patients are undergoing uniocular cataract extraction. We aim to compare the binocular status of subjects with uniocular cataracts, implanted either with a multifocal or a monofocal intraocular lens (IOL).

Materials and Methods

Subjects were recruited from outpatient ophthalmology clinics and randomized to an IOL type. Corrected and uncorrected LogMAR distance visual acuity (VA) and near and intermediate VA using the Radner reading test were completed. The binocular tests included the Worth Four Dot Test, fixation disparity, TNO stereoacuity and foveal suppression assessment. In addition to the near activity vision questionnaire. The trial was closed early because the chosen multifocal lens had been superseded by newer models. We report two subjects, one receiving the multifocal IOL and a monofocal IOL control with the most comparable baseline characteristics.

Results

Both subjects experienced uncomplicated cataract surgery, showing clinically significant improved corrected distance VA, 0.06 LogMAR and −0.16 LogMAR in the monofocal and multifocal IOL, respectively. The multifocal subject had 30 seconds of arc stereoacuity indicating normal binocular vision. Only gross binocular single vision with no stereopsis was found in the monofocal IOL subject. The latter subject also had reduced near vision quality-of-life questionnaire results.

Conclusion

This two-patient case series demonstrates greater binocular near ability, with the multifocal IOL, in the pre-presbyopic patient undergoing uniocular cataract surgery. The case series highlights the need, and methodology for investigating further the functional and quality-of-life benefits of implanting multifocal IOLs in pre-presbyopic patients, those in their twenties and thirties, undergoing uniocular cataract surgery.

Cataract service redesign in the post-COVID-19 era

COVID-19 pandemic of 2020 has impacted all aspects of clinical practice in the UK. Cataract services suffered severe disruption due to necessary measures taken to reduce elective surgery in order to release capacity to support intensive care requirements. Faced with a potential 50% increase in cataract surgery workload per week in the post-COVID-19 world, eye units should use this event to innovate, not just survive but to also evolve for a sustainable future. In this article, we discuss the inadequacies of existing service rationing options to tackle the COVID-19 cataract backlog. This includes limiting rationing based on visual acuity, limiting surgery to first or only seeing eyes, and postponing clinic and surgical dates according to referral dates. We propose units use the lockdown time to reset and develop a comprehensive patient-centred care pathway using principles of value-based healthcare: the cataract integrated practice units. Developing an agile surgical database that incorporates all aspects of patient need from education to follow-up in their individual cataract journey will allow units to react and plan quickly in the early phase of recovery and beyond. We also discuss the considerations units should bear in mind on telemedicine, modifications for face-to-face clinics, theatre organisation and options of expanding cataract throughput capacity. The pause in elective surgery due to the pandemic may have provided cataract services a rare opportunity to reset and transform cataract service pathways for the digital era.

Risk of falls and injuries requiring hospitalisation after first-eye cataract surgery in elderly Australians

PURPOSE

To investigate the impact of the type of the intraocular lenses (IOLs) in first-eye cataract surgery in elderly people on the risk of hospitalisation due to falls and injuries.

METHODS

A retrospective cohort study was conducted using the Australian Government Department Veterans' Affairs claims data. All people aged 65 years and above who had first cataract surgery between January 2007 and July 2017 were identified. Two cohorts were established depending on the type of IOL-monofocal and multifocal. The risk of injuries and falls requiring hospitalisation in the first 3 months post the surgery was assessed using Cox proportional hazard models with age at entry as primary time scale and adjusting for gender, comorbidities and prior history of falls.

RESULTS

There were 45 728 people across the two cohorts with the majority receiving monofocal lenses (97%), followed by multifocal lenses (3%) at the time of first cataract surgery. The risk of injury and falls was lower (but not significant) in the multifocal cohort compared to monofocal cohort (adjusted hazard ratio (aHR) 0.56, 95% CI 0.26-1.17). The risk was also lower (but not significant) when stratifying by age group at the time of the surgery.

CONCLUSIONS

Regardless of age, multifocal lenses did not appear to be associated with the higher risk of serious injuries and falls after first-eye cataract surgery compared to monofocal lenses.

Impact of first and second eye cataract surgery on physical activity: a prospective study

OBJECTIVES

To investigate the impact of first eye and second eye cataract surgery on the level of physical activity undertaken by older adults with bilateral cataract.

DESIGN

Prospective cohort study.

SETTING

Three public ophthalmology clinics in Western Australia.

PARTICIPANTS

Fifty-five older adults with bilateral cataract aged 55+ years, awaiting first eye cataract surgery.

OUTCOME MEASURES

The primary outcome measure was participation in moderate leisure-time physical activity. The secondary outcomes were participation in walking, gardening and vigorous leisure-time physical activity. Participants completed a researcher-administered questionnaire, containing the Active Australia Survey and visual tests before first eye cataract surgery, after first eye surgery and after second eye surgery. A Generalised Estimating Equation linear regression model was undertaken to analyse the change in moderate leisure-time physical activity participation before first eye surgery, after first eye surgery and after second eye surgery, after accounting for relevant confounders.

RESULTS

Participants spent significantly less time per week (20 min) on moderate leisure-time physical activity before first eye cataract surgery compared with after first eye surgery (p=0.04) after accounting for confounders. After second eye cataract surgery, participants spent significantly more time per week (32 min) on moderate physical activity compared with after first eye surgery (p=0.02). There were no significant changes in walking, gardening and vigorous physical activity throughout the cataract surgery process.

CONCLUSION

First and second eye cataract surgery each independently increased participation in moderate leisure-time physical activity. This provides a rationale for timely first and second eye cataract surgery for bilateral cataract patients, even when they have relatively good vision.

Binocular vision alterations after refractive and cataract surgery: a review

To review binocular and accommodative disorders documented after corneal or intraocular refractive surgery, in normal healthy prepresbyopic patients. A bibliographic revision was performed; it included works published before 1st July 2017 where accommodation and/or binocularity was assessed following any type of refractive surgical procedure. The search in Pubmed yielded 1273 papers, 95 of which fulfilled the inclusion criteria. Few publications reporting binocular vision and/or accommodative changes after refractive surgery in normal subjects were found. The reduction in fusional vergence is the most frequently reported alteration. Anisometropia is an important risk factor for postoperative binocular vision-related complaints. Most diplopia-related visual complaints, irrespective of the surgical procedure, were in fact misdiagnosed preoperative disorders. The preoperative evaluation of patients seeking spectacle/contact lens independence should include a complete binocular and accommodation assessment where parameters such as the phoric posture, accommodative amplitude and facility, near point of convergence, fusional reserves and accommodative convergence/accommodation coefficient are measured. This would allow the identification of risk factors that could compromise the success of the refractive surgery and cause clinical symptoms.

The impact of first- and second-eye cataract surgery on motor vehicle crashes and associated costs

Objective

to evaluate the association between first- and second-eye cataract surgery and motor vehicle crashes for older drivers and the associated costs to the community.

Design

retrospective population-based cohort study.

Subjects

a total of 2,849 drivers aged 60 years and older who had undergone both first- and second-eye cataract surgery were involved in 3,113 motor vehicle crashes as drivers during the study period.

Methods

de-identified data were obtained using the Western Australian Data Linkage System from 1 January 2003 to 31 December 2015. Poisson regression analysis based on Generalised Estimating Equations was undertaken to compare the frequency of crashes in the year before first eye cataract surgery, between first and second eye surgery and 1 year after second eye surgery.

Results

first eye cataract surgery was associated with a significant 61% reduction in crash frequency (P < 0.001) and second eye surgery was associated with a significant 23% reduction in crashes (P < 0.001), compared to the year before first eye cataract surgery after accounting for age, gender, marital status, accessibility, socio-economic status, driving exposure and comorbidities. The estimated cost savings from the reduction in crashes in the year after second eye cataract surgery compared to the year before first eye cataract surgery was $14.9 million.

Conclusions

first- and second-eye cataract surgery were associated with a significant reduction in motor vehicle crashes, with first eye surgery having the greatest impact. These results provide encouragement for the timely provision of first- and second-eye cataract surgery for older drivers.

The impact of first and second eye cataract surgeries on falls: a prospective cohort study

Purpose

The purpose of this study was to investigate the impact of the first and second eye cataract surgeries on the risk of falls in participants with bilateral cataract and to determine which changes in visual measures are associated with changes in the number of falls throughout the cataract surgery process.

Patients and methods

Fifty-five older adults with bilateral cataract aged 55+ years were assessed at three time points during the cataract surgery process, and they completed a falls diary. Two separate generalized estimating equation-negative binomial models were undertaken to assess changes in the number of falls before first eye cataract surgery, between first and second eye surgeries, and after second eye cataract surgery and which changes in visual measures were associated with changes in the number of falls.

Results

After adjusting for potential confounding factors, the risk of falls decreased by 54% (incidence rate ratio (IRR) =0.458, 95% CI=0.215-0.974, p=0.04) after first eye cataract surgery only, compared with the period before first eye surgery. The risk of falls decreased by 73% (IRR =0.268, 95% CI =0.114-0.628, p=0.002) after second eye cataract surgery, compared with the period before first eye surgery. Improved binocular visual acuity (IRR =5.488, 95% CI =1.191-25.282, p=0.029) and contrast sensitivity (IRR =0.257, 95% CI =0.070-0.939, p=0.040) were associated with a decrease in the number of falls.

Conclusion

The study found that first and second eye cataract surgeries reduced the risk of falls among a cohort of bilateral cataract patients with relatively good baseline vision. This suggests that timely first and second eye cataract surgeries could play an important role in reducing the burden due to falls among older adults with cataract.

Patient perspectives of cataract surgery: protocol and baseline findings of a cohort study

BACKGROUND

Patient-reported outcome measures (PROMs) are becoming increasingly recognised as a key component in assessing the relative effectiveness of cataract surgery. This manuscript presents the protocol methodology and baseline characteristics of a prospective cohort study investigating patient-centred predictors of cataract surgery outcomes.

METHODS

Patients with bilateral cataract (aged ≥ 50 years) scheduled for their first eye cataract surgery were recruited at four public hospitals and three private ophthalmology clinics in Sydney, Australia. Participants underwent a comprehensive assessment of clinical measures of vision (for example, visual acuity, contrast sensitivity) and PROMs prior to first eye surgery and three months after first and second eye surgery. The PROMs of interest included health-related quality of life, visual disability and satisfaction with vision.

RESULTS

The characteristics of the baseline cohort of 359 participants are reported in this manuscript. Enrolment occurred over a two-year period with the majority recruited from urban public hospitals (96 per cent, n = 345). Health-related quality of life was scored highly (80 out of 100). Self-reported visual disability was considered within normal ranges compared to cataract populations in other high-income countries (-0.94 logits). Three-quarters of participants (n = 263/351) were dissatisfied with their pre-operative vision.

CONCLUSIONS

There is a complex and wide range of patient-centred experiences prior to first eye cataract surgery in the public hospital setting. Gaining further insight into the patient perspective may allow eye health professionals to more appropriately time surgery, better manage patient expectations and provide direction for future prioritisation initiatives of cataract wait lists. Companion papers will follow, detailing results of surgery in terms of PROMs.

First and second eye cataract surgery and driver self-regulation among older drivers with bilateral cataract: a prospective cohort study

Background

Driving a car is the most common form of transport among the older population. Common medical conditions such as cataract, increase with age and impact on the ability to drive. To compensate for visual decline, some cataract patients may self-regulate their driving while waiting for cataract surgery. However, little is known about the self-regulation practices of older drivers throughout the cataract surgery process. The aim of this study is to assess the impact of first and second eye cataract surgery on driver self-regulation practices, and to determine which objective measures of vision are associated with driver self-regulation.

Methods

Fifty-five older drivers with bilateral cataract aged 55+ years were assessed using the self-reported Driving Habits Questionnaire, the Mini-Mental State Examination and three objective visual measures in the month before cataract surgery, at least one to three months after first eye cataract surgery and at least one month after second eye cataract surgery. Participants’ natural driving behaviour in four driving situations was also examined for one week using an in-vehicle monitoring device. Two separate Generalised Estimating Equation logistic models were undertaken to assess the impact of first and second eye cataract surgery on driver-self-regulation status and which changes in visual measures were associated with driver self-regulation status.

Results

The odds of being a self-regulator in at least one driving situation significantly decreased by 70% after first eye cataract surgery (OR: 0.3, 95% CI: 0.1–0.7) and by 90% after second eye surgery (OR: 0.1, 95% CI: 0.1–0.4), compared to before first eye surgery. Improvement in contrast sensitivity after cataract surgery was significantly associated with decreased odds of self-regulation (OR: 0.02, 95% CI: 0.01–0.4).

Conclusions

The findings provide a strong rationale for providing timely first and second eye cataract surgery for older drivers with bilateral cataract, in order to improve their mobility and independence.

Bilateral symmetry in vision and influence of ocular surgical procedures on binocular vision: A topical review

We analyze the role of bilateral symmetry in enhancing binocular visual ability in human eyes, and further explore how efficiently bilateral symmetry is preserved in different ocular surgical procedures. The inclusion criterion for this review was strict relevance to the clinical questions under research. Enantiomorphism has been reported in lower order aberrations, higher order aberrations and cone directionality. When contrast differs in the two eyes, binocular acuity is better than monocular acuity of the eye that receives higher contrast. Anisometropia has an uncommon occurrence in large populations. Anisometropia seen in infancy and childhood is transitory and of little consequence for the visual acuity. Binocular summation of contrast signals declines with age, independent of inter-ocular differences. The symmetric associations between the right and left eye could be explained by the symmetry in pupil offset and visual axis which is always nasal in both eyes. Binocular summation mitigates poor visual performance under low luminance conditions and strong inter-ocular disparity detrimentally affects binocular summation. Considerable symmetry of response exists in fellow eyes of patients undergoing myopic PRK and LASIK, however the method to determine whether or not symmetry is maintained consist of comparing individual terms in a variety of ad hoc ways both before and after the refractive surgery, ignoring the fact that retinal image quality for any individual is based on the sum of all terms. The analysis of bilateral symmetry should be related to the patients' binocular vision status. The role of aberrations in monocular and binocular vision needs further investigation.

Indication for cataract surgery. Do we have evidence of who will benefit from surgery? A systematic review and meta-analysis

The need for cataract surgery is expected to rise dramatically in the future due to the increasing proportion of elderly citizens and increasing demands for optimum visual function. The aim of this study was to provide an evidence-based recommendation for the indication of cataract surgery based on which group of patients are most likely to benefit from surgery. A systematic literature search was performed in the MEDLINE, CINAHL, EMBASE and COCHRANE LIBRARY databases. Studies evaluating the outcome after cataract surgery according to preoperative visual acuity and visual complaints were included in a meta-analysis. We identified eight observational studies comparing outcome after cataract surgery in patients with poor (<20/40) and fair (>20/40) preoperative visual acuity. We could not find any studies that compared outcome after cataract surgery in patients with few or many preoperative visual complaints. A meta-analysis showed that the outcome of cataract surgery, evaluated as objective and subjective visual improvement, was independent on preoperative visual acuity. There is a lack of scientific evidence to guide the clinician in deciding which patients are most likely to benefit from surgery. To overcome this shortage of evidence, many systems have been developed internationally to prioritize patients on waiting lists for cataract surgery, but the Swedish NIKE (Nationell Indikationsmodell för Katarakt Ekstraktion) is the only system where an association to the preoperative scoring of a patient has been related to outcome of cataract surgery. We advise that clinicians are inspired by the NIKE system when they decide which patients to operate to ensure that surgery is only offered to patients who are expected to benefit from cataract surgery.

The Influence of a Prolonged Interoperative Period on Binocular Vision after Bilateral Cataract Extractions

Purpose

To evaluate the influence of the extent of the interoperative period on binocular vision function in patients after consecutive bilateral cataract extractions and intraocular lens implantation.

Methods

The study included patients operated due to bilateral cataract. Presence of asthenopic symptoms, distance and near squint angle, fusional amplitudes, stereopsis, and convergence were evaluated. Preoperative, interoperative, and postoperative differences in best-corrected visual acuity between eyes were also noted. Multivariate analysis was conducted in order to establish the relation between the interoperative period and binocular status.

Results

The study included 104 patients (74 female, 30 male, mean age 69.9 years, range 32-88). Mean interoperative period was 20.3 ± 12.9 months, range 1.5-47.7. Prolongation of the interoperative interval had a significant negative impact on stereopsis measured by TNO ( R2 = 0.215, p = 0.001) and Randot ( R2 = 0.179, p = 0.001) stereotests, as well as for near point of convergence ( R2 = 0.09, p = 0.002). It was also related, but not independently, to reduction in fusional amplitudes, mainly for distance ( R2 = 0.18, p = 0.001 for divergence and R2 = 0.12, p = 0.001 for convergence). Asthenopic symptoms were reported by 17 (16.3%) patients. The incidence of exophoria was significantly (p = 0.002) higher in patients with an interoperative interval longer than 24 months.

Conclusions

The length of the interoperative period influences the status of binocular vision in patients after bilateral cataract extraction. It is also connected with an increased number of patients with asthenopic symptoms and exophoria.

The impact of first- and second-eye cataract surgery on injurious falls that require hospitalisation: a whole-population study

BACKGROUND

cataract is a leading cause of reversible vision impairment and may increase falls in older adults.

OBJECTIVE

to assess the risk of an injury due to a fall among adults aged 60+, 2 years before first-eye cataract surgery, between first-eye surgery and second-eye surgery and 2 years after second-eye surgery.

DESIGN

a retrospective cohort study.

SETTING

Western Australian Hospital Morbidity Data System and the Western Australian Death Registry.

SUBJECTS

there were 28,396 individuals aged 60+ years who underwent bilateral cataract surgery in Western Australia between 2001 and 2008.

METHODS

Poisson regression analysis based on generalised estimating equations compared the frequency of falls 2 years before first-eye cataract surgery, between first- and second-eye surgery and 2 years after second-eye cataract surgery after accounting for potential confounders.

RESULTS

the risk of an injurious fall that required hospitalisation doubled (risk ratio: 2.14, 95% confidence interval: 1.82 to 2.51) between first- and second-eye cataract surgery compared with the 2 years before first-eye surgery. There was a 34% increase in the number of injurious falls that required hospitalisation in the 2 years after second-eye cataract surgery compared with the 2 years before first-eye surgery (risk ratio: 1.34, 95% confidence interval: 1.16-1.55).

CONCLUSIONS

there was an increased risk of injurious falls after first- and second-eye cataract surgery which has implications for the timely provision of second-eye surgery as well as appropriate refractive management between surgeries.

Vision, quality of life and depressive symptoms after first eye cataract surgery

BACKGROUND

Cataract affects not only vision, but also performance of everyday tasks, participation in social activities, quality of life and possibly depression. Depression is a major health issue for older adults. It is estimated that 6%-20% of community-dwelling older Australians experience depression. The aim of this study was to investigate changes in vision-related quality of life and depressive symptoms after first eye cataract surgery and to determine which visual measures affect the change in these outcomes.

METHODS

In 2009 and 2010, 99 participants with bilateral cataract were recruited. Visual measures including visual acuity, contrast sensitivity and stereopsis were assessed 1 week before and 12 weeks after first eye cataract surgery. Vision-related quality of life was measured using the 25-item National Eye Institute Visual Function Questionnaire. Depressive symptoms were assessed by the 20-item Center for Epidemiological Studies Depression Scale. Separate regression analyses were undertaken to determine the association between visual measures and changes in vision-related quality of life and depressive symptoms after first eye cataract surgery.

RESULTS

Overall, vision-related quality of life improved after first eye cataract surgery. There was a small, non-clinically significant improvement in depressive symptoms after surgery. Improvement in vision-related quality of life after first eye cataract surgery was associated with improved contrast sensitivity in the operated eye (P < 0.001), whereas improvement in depressive symptoms after surgery was associated with improved stereopsis (P = 0.032).

CONCLUSIONS

Contrast sensitivity and stereopsis, but not visual acuity, were significant factors affecting improvement in vision-related quality of life or depressive symptoms after first eye cataract surgery.

Driver self-regulation and depressive symptoms in cataract patients awaiting surgery: a cross-sectional study

BACKGROUND

Cataract is an extremely common visual condition of ageing. Evidence suggests that visual impairment influences driving patterns and self-regulatory behavior among older drivers. However, little is known about the psychological effects of driver self-regulation among older drivers. Therefore, this study aimed to describe driver self-regulation practices among older bilateral cataract patients and to determine the association between self-regulation and depressive symptoms.

METHODS

Ninety-nine older drivers with bilateral cataract were assessed the week before first eye cataract surgery. Driver self-regulation was measured via the Driving Habits Questionnaire. Depressive symptoms were assessed using the 20-item Center for Epidemiological Studies Depression Scale. Visual, demographic and cognitive data were also collected. Differences between self-regulators and non self-regulators were described and linear regression modeling used to determine the association between driver self-regulation and depressive symptoms score.

RESULTS

Among cataract patients, 48% reported self-regulating their driving to avoid at least one challenging situation. The situations most commonly avoided were driving at night (40%), on the freeway (12%), in the rain (9%) and parallel parking (8%). Self-regulators had significantly poorer contrast sensitivity in their worse eye than non self-regulators (p = 0.027). Driver self-regulation was significantly associated with increased depressive symptoms after controlling for potential confounding factors (p = 0.002).

CONCLUSIONS

Driver self-regulation was associated with increased depressive symptoms among cataract patients. Further research should investigate this association among the general older population. Self-regulation programs aimed at older drivers may need to incorporate mental health elements to counteract unintended psychological effects.

Which visual measures affect change in driving difficulty after first eye cataract surgery?

OBJECTIVE

To investigate self-reported driving difficulty before and after first eye cataract surgery and determine which visual measures are associated with changes in self-reported driving difficulty after surgery.

METHODS

A cohort of 99 older drivers with bilateral cataract were assessed the week before and 12 weeks after first eye cataract surgery. Visual measures including visual acuity, contrast sensitivity, stereopsis and useful field of view were assessed. Self-reported driving difficulty was measured via the Driving Habits Questionnaire. Cognitive status was assessed using the Mini Mental State Examination. Regression analysis was undertaken to determine the association between changes in visual measures and self-reported driving difficulty after first eye cataract surgery.

RESULTS

Overall, self-reported driving difficulty improved after first eye cataract surgery. However, 16% of participants did not improve and driving difficulty worsened in 11% following surgery. Improvement in driving difficulty score after first eye cataract surgery was associated with improved contrast sensitivity in the operated eye (p<0.001), new glasses after surgery (p<0.001), and fewer chronic health conditions (p=0.016).

CONCLUSION

Contrast sensitivity rather than visual acuity was a significant factor affecting change in self-reported driving difficulty after first eye cataract surgery for bilateral patients. This has implications for driver licensing authorities worldwide that rely heavily on visual acuity as a measure of visual fitness to drive.

Asymmetry in keratoconus and vision-related quality of life

PURPOSE

To examine the relationship of increased ocular asymmetry over time to vision-related quality of life in keratoconus.

METHODS

The subjects were from the Collaborative Longitudinal Evaluation of Keratoconus Study and had complete data on a least 1 scale of the National Eye Institute Visual Function Questionnaire and examination data at baseline and at least 1 follow-up visit. Three measures of disease asymmetry [visual acuity (VA), corneal curvature, and refractive error] and better eye status were assessed. Multilevel models were fit to the data.

RESULTS

The analyses were completed using the data from 961 subjects. Six scales on the National Eye Institute Visual Function Questionnaire had adequate variability to the model (distance activity, driving, mental health, near activity, ocular pain, and role difficulties). Refractive error changes were not associated with statistically significant quality-of-life differences. Except for ocular pain, statistically significant, but not clinically meaningful, differences were found for VA changes and corneal curvature changes. For a 0.1-unit logarithm of the minimum angle of resolution of VA change, the quality-of-life scales decreased between 0.20 and 0.99 units. For a 1.00-diopter steepening of corneal curvature, these decreases were on the order of 0.20 to 0.59 units. Changes related to asymmetry were small as well; decreases were on the order of 0.20 to 0.38 units.

CONCLUSIONS

Increasing ocular asymmetry and decreases in VA and corneal steepening in the better eye were associated with decreasing vision-related quality of life, although the magnitudes of the changes were not clinically meaningful. Of these 2 disease status indicators, the vision in the better eye had greater effect on the vision-related quality of life.

First eye cataract surgery and hospitalization from injuries due to a fall: a population-based study

OBJECTIVES

To assess the association between first eye cataract surgery and hospitalization from injuries due to a fall in older adults at the population level.

DESIGN

Retrospective population-based study.

SETTING

Western Australian Hospital Morbidity Data System and Western Australian mortality data.

PARTICIPANTS

Six hundred individuals aged 60 and older hospitalized from injuries due to a fall between 2004 and 2008 in Western Australia.

MEASUREMENTS

Hospital admission from injuries due to a fall.

RESULTS

Of the 15,295 individuals who underwent cataract surgery in one eye only, 600 (3.9%) were involved in 625 hospital admissions from injuries due to a fall 1 year before (n = 273) or 1 year after (n = 352) first eye cataract surgery; 30% of these hospitalizations were for femoral neck fractures. Poisson generalized estimating equations confirmed 27% more (adjusted risk ratio = 1.27, 95% confidence interval = 1.04-1.56 P = .02) hospitalizations from injuries due to a fall in the year after first eye cataract surgery than in the year before.

CONCLUSION

First eye cataract surgery was associated with more hospital admissions from injuries due to a fall in the year after cataract surgery than in the year before. Further research is needed to determine the underlying causes and reasons.

Monocular vs. binocular measurement of spatial vision in elders

PURPOSE

To evaluate the frequency and magnitude of binocular gain (and loss) for high-contrast acuity, various low-contrast spatial vision measures and contrast sensitivity in an elderly population.

METHODS

Ninety-five individuals over the age of 70 (mean age 80.5 years, range, 71.8 to 93.5) with acuity of 20/40 (logMAR 0.3) or better in at least one eye participated. Each individual was tested binocularly and then monocularly on high-contrast acuity, various low-contrast acuity measures, and contrast sensitivity. Binocular gain for acuity measures was defined as better performance by one line or more under binocular conditions than with the better eye alone. Binocular loss was defined as poorer performance by one line or more binocularly than with the better eye alone. For contrast sensitivity, the criterion for binocular gain or loss was one letter triplet (0.15 log unit) or more difference. For each measure, the frequency of binocular gain and loss, as well as the mean gain or loss were determined.

RESULTS

The mean difference between binocular and better eye monocular acuity was <2 letters for all measures, suggesting little gain or loss. However, the percent of individuals showing a line or more of gain or loss ranged from approximately 20% for high-contrast acuity to 49.5% for low-contrast acuity at low luminance. This indicates that for 1/5 to (1/2) of individuals, binocular vision is not well represented by monocular vision measures. All low contrast measures and contrast sensitivity show more binocular gain/loss than standard acuity. As has been previously reported, in the presence of large interocular differences, binocular gain is not seen, but binocular loss does not necessarily occur.

CONCLUSIONS

For a significant portion of this elderly population, binocular performance is not well represented by better eye monocular measures. This indicates that to get a true sense of an individual';s vision function in daily life, one must measure vision binocularly.

Binocular interaction in post-LASIK subjects with unsatisfactory outcome

PURPOSE

A shift from binocular summation to binocular inhibition has been observed when there is a significant decrease in contrast sensitivity or reduced retinal illuminance in one eye compared to the other as in cases of unilateral cataract and amblyopia. This study aims to determine how binocular function in post-LASIK subjects with unsatisfactory outcomes is influenced by differences between the two eyes in visual acuity and contrast sensitivity.

MATERIALS AND METHODS

A retrospective analysis of monocular and binocular visual acuity (VA) and contrast sensitivity (CS) results was performed for 23 LASIK subjects who previously underwent a Functional Vision Test battery at Vision Sciences Research Corp. (San Ramon, CA). Photopic VA was measured with ETDRS chart and sine-wave grating CS was measured with FACT chart.

RESULTS

The difference between binocular and better monocular VA and CS was calculated for each subject and referred to as binocular difference. The interocular difference was calculated as better eye-worse eye for VA and CS. Significant negative correlations (P < 0.01) were observed between binocular difference and interocular difference for VA (r = -0.84) and CS at each spatial frequency of 1.5 (r = -0.90), 3 (r = -0.85), 6 (r = -0.79), 12 (r = -0.68), and 18c/d (r = -0.72). The greater the difference between the eyes, the lesser the binocular summation. Linear regression predicted a 1-line decrease in binocular summation for a 4-line increase in interocular acuity difference and a 35% decrease in binocular summation for a 50% increase in interocular difference of contrast sensitivity at 3c/d (ANOVA, P < 0.01).

CONCLUSIONS

Binocular inhibition in post-LASIK subjects increases as the visual sensitivity difference between the two eyes increases. Since the peak of human contrast sensitivity function is at the middle spatial frequencies, the decrease in binocular CS at 3c/d due to reduced CS in one eye is functionally significant.

Gait alterations negotiating a raised surface induced by monocular blur

PURPOSE

Falls in the elderly are a major cause of serious injury and mortality. Impaired and absent stereopsis may be a significant risk factor for falls or hip fracture, although data from epidemiological studies are not consistent. Previous laboratory based studies, however, do suggest that stereoacuity is an important factor in adaptive gait. The present study investigates how acute impairment of stereopsis, through monocular blur of differing levels, ranging from 0.50 diopter (D) to a monovision correction affected gait when negotiating a raised surface in elderly subjects.

METHOD

Eleven elderly subjects (73.3 +/- 3.6 years) walked up to and negotiated a raised surface under nine visual conditions, binocular vision, one eye occluded and 0.50 D, 1.00 D and monovision correction (mean 2.50 D +/- 0.20 D) with blur and occlusion either over the dominant or non-dominant eye. Analysis focused on foot positioning and toe clearance parameters.

RESULTS

There was no effect of ocular dominance on any parameters. Monocular blur impaired stereopsis (p < 0.01), with more minor effects on high and low contrast acuity. Vertical and horizontal lead limb toe clearance both increased under all levels of monocular blur including the lowest level of 0.50 DBlur (p = 0.03) and monovision correction led to toe clearance levels similar to that found with occlusion of one eye.

CONCLUSIONS

Findings demonstrated that even small amounts of monocular blur can lead to a change in gait when negotiating a raised surface, suggesting acute monocular blur affected the ability to accurately judge the height of a step in the travel path. Further work is required to investigate if similar adaptations are used by patients with chronic monocular blur.