Measuring contrast sensitivity under different lighting conditions: comparison of three tests

BCLA CLEAR Presbyopia: Evaluation and diagnosis

It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power. Both subjective and objective techniques are necessary: subjective techniques (such as patient reported outcome questionnaires and defocus curves) assess the impact of presbyopia on a patient and how the combination of residual objective accommodation and their natural DoF work for them; objective techniques (such as autorefraction, corneal topography and lens imaging) allow the clinician to understand how well a technique is working optically and whether it is the right choice or how adjustments can be made to optimise performance. Techniques to assess visual performance and adverse effects must be carefully conducted to gain a reliable end-point, considering the target size, contrast and illumination. Objective techniques are generally more reliable, can help to explain unexpected subjective results and imaging can be a powerful communication tool with patients. A clear diagnosis, excluding factors such as binocular vision issues or digital eye strain that can also cause similar symptoms, is critical for the patient to understand and adapt to presbyopia. Some corrective options are more permanent, such as implanted inlays / intraocular lenses or laser refractive surgery, so the optics can be trialled with contact lenses in advance (including differences between the eyes) to better communicate with the patient how the optics will work for them so they can make an informed choice.

Pushing the envelope: the feasibility of using a mailed contrast sensitivity test to prioritise cataract waiting lists

BACKGROUND

Cataract waiting lists are growing globally. Pragmatic, cost-effective methods are required to prioritise the most urgent cases. Here we investigate the feasibility of using a third-party pen-and-paper contrast sensitivity, CS, test (SpotChecksTM), delivered by mail, and performed by patients at home unsupervised, to flag eyes requiring surgery.

METHODS

Pen-and-paper CS tests were mailed to 233 people waiting for a cataract assessment, along with a prepaid return envelope (cross-sectional study). Response rates were tabulated (stratified by age, sex and socioeconomic status), and test scores analysed to see how well the home tests predicted which eyes were listed subsequently for surgery. A subset of patients (N = 39) also underwent in-person follow-up testing, to confirm the accuracy of the home data.

RESULTS

Forty-six percent of patients responded (216 eyes). No gross differences were observed between respondents and non-respondents, either in terms of age, sex, socioeconomic status, or geographic location (all P > 0.05). The home-test CS scores predicted which eyes were subsequently listed for surgery, with an AUROC {±CI95%} of 0.69 {0.61-0.76}. Predictive performance was further-improved when machine learning was used to combine CS scores with letter acuity, extracted from patients' medical records (AUROC {±CI95%} = 0.77 {0.70-0.83}). Among 39 patients who underwent follow-up testing, home CS scores were correlated with various measures made in clinic: biometry signal-to-noise (P = 0.032), LogMAR acuity, Pelli-Robson CS and SpotChecks CS (all P < 0.001).

CONCLUSIONS

Mailing patients pen-and-paper CS tests may be a feasible, 'low-tech' way of prioritising patients on cataract waiting lists.

Short-term clinical outcomes after implantation of monofocal intraocular lens with enhanced intermediate function in eyes with epiretinal membrane

Our study evaluated the clinical outcomes after implantation of a monofocal intraocular lens (IOL) with enhanced intermediate function in eyes with epiretinal membrane (ERM). Patients with preexisting ERM who underwent cataract surgery with implantation of monofocal IOL with enhanced intermediate function were included retrospectively. According to the ERM grade and central subfield thickness (CST) obtained from preoperative optical coherence tomography, patients were divided into non-fovea-involving and fovea-involving ERM groups. At 1 month after surgery, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), contrast sensitivity, defocus curve, and satisfaction questionnaire were evaluated. Postoperative clinical findings were compared with age-matched controls without ERM. A total of 50 patients' eyes (28 and 22 in the non-fovea-involving and fovea-involving ERM groups, respectively) were compared with 42 control eyes. One month post-surgery, significant differences in UDVA, CDVA, and CST (corrected P was < 0.001, = 0.001, and < 0.001, respectively) were observed between the fovea-involving ERM and control group; however, no significant differences in UIVA and UNVA were observed between the two groups. Contrast sensitivity showed inferior results in the fovea-involving group without significance. Photic phenomena were reported less in the fovea-involving group than in the non-fovea-involving group. More than 70% of patients in both ERM groups were satisfied. Implantation of monofocal IOL with enhanced intermediate function could be a good option for patients with ERM that need intermediate vision.

Machine Independence of Ultrasound-Based Quantification of Vitreous Echodensities

Purpose

Quantitative ultrasound (QUS) provides objective indices of Vision Degrading Myodesopsia (VDM) that correlate with contrast sensitivity (CS). To date, QUS methods were only tested on a single ultrasound machine. Here, we evaluate whether QUS measurements are machine independent.

Methods

In this cross-sectional study, 47 eyes (24 subjects; age = 53.2 ± 14.4 years) were evaluated with Freiburg acuity contrast testing (%Weber), and ultrasonography using 2 machines: one with a 15-MHz single-element transducer and one with a 5-ring, 20-MHz annular-array. Images were acquired from each system in sequential scans. Artifact-free, log-compressed envelope data were processed to yield three parameters (mean amplitude, M; energy, E; and percentage filled by echodensities, P50) and a composite score (C). A B-mode normalization method was applied to the 20-MHz datasets to match QUS parameters at both frequencies. Statistical analyses were performed to evaluate correlations among CS, E, M, P50, and C for both machines.

Results

QUS parameters from each machine correlated with CS (R ≥ 0.57, P < 0.001) and there was correlation between machines (R ≥ 0.84, P < 0.001). Correlations between CS and QUS parameters were statistically similar for both machines (P ≥ 0.14) except when the 20-MHz data were normalized (P = 0.04). Reproducibility of QUS parameters computed from 20-MHz data were satisfactory (52.3%-96.3%) with intraclass correlation values exceeding 0.80 (P < 0.001).

Conclusions

The high correlation between QUS parameters from both machines combined with a statistically similar correlation to CS suggests QUS is an effective, machine-independent, quantitative measure of vitreous echodensities.

Translational Relevance

QUS may be applied across clinical ophthalmic ultrasound scanners and imaging frequencies to effectively evaluate VDM.

Early Outcomes of Two Treatment Modes of PresbyLASIK: Monocular vs. Micro-Monovision

PURPOSE

To report the visual, refractive and subjective outcomes of presbyLASIK for the correction of presbyopia.

METHODS

Monocular (20 eyes) or micro-monovision (12 eyes) presbyLASIK was performed on a total of 32 eyes in 16 patients (50% female, average age 55±4.6 years) using the Zeiss VisuMax 400Hz femtosecond and Schwind Amaris 1050RS excimer laser platform. Predictability, safety and efficacy were assessed and compared at 4-6 weeks, 3 months and 6 months. Results were considered significant if P < 0.05.

RESULTS

For monocular treatments, average postoperative spherical equivalent (SE) was 0.1±0.1 D and -0.86±0.5 D at 4-6 weeks postoperatively for distance and near eyes respectively; 90% eyes achieved SE ±1.0 D of the target. Postoperative binocular uncorrected distance (UDVA), intermediate (UIVA) and near visual acuity (UNVA) were -0.03±0.1 LogMAR (20/20), 0.09±0.26 LogMAR (N4) and 0.29±0.11 LogMAR (N6) respectively with 90% patients achieving binocular UDVA of 20/20 or better. For micro-monovision treatments, average postoperative SE was -0.33±0.51 D and -1.60±0.78 D at 4-6 weeks postoperatively for distance and near eyes respectively; 100% eyes achieved SE ±1.0 D of the target. Postoperative binocular UDVA, UIVA and UNVA were 0.05±0.16 LogMAR (20/20), -0.02±0.10 LogMAR (N3) and 0.23±0.08 LogMAR (N5) respectively with 67% patients achieving binocular UDVA of 20/20 or better.

CONCLUSION

Monocular and micro-monovision presbyLASIK are both effective options for the treatment of presbyopia. Monocular treatments are more likely to be well tolerated by patients who prefer to preserve exceptional distance vision, while micro-monovision treatments may be better suited to patients who can tolerate compromises in distance vision in order to attain greater intermediate vision function.

Age-related normal limits for spatial vision

PURPOSE

To establish age-related, normal limits of monocular and binocular spatial vision under photopic and mesopic conditions.

METHODS

Photopic and mesopic visual acuity (VA) and contrast thresholds (CTs) were measured with both positive and negative contrast optotypes under binocular and monocular viewing conditions using the Acuity-Plus (AP) test. The experiments were carried out on participants (age range from 10 to 86 years), who met pre-established, normal sight criteria. Mean and ± 2.5σ limits were calculated within each 5-year subgroup. A biologically meaningful model was then fitted to predict mean values and upper and lower threshold limits for VA and CT as a function of age. The best-fit model parameters describe normal aging of spatial vision for each of the 16 experimental conditions investigated.

RESULTS

Out of the 382 participants recruited for this study, 285 participants passed the selection criteria for normal aging. Log transforms were applied to ensure approximate normal distributions. Outliers were also removed for each of the 16 stimulus conditions investigated based on the ±2.5σ limit criterion. VA, CTs and the overall variability were found to be age-invariant up to ~50 years in the photopic condition. A lower, age-invariant limit of ~30 years was more appropriate for the mesopic range with a gradual, but accelerating increase in both mean thresholds and intersubject variability above this age. Binocular thresholds were smaller and much less variable when compared to the thresholds measured in either eye. Results with negative contrast optotypes were significantly better than the corresponding results measured with positive contrast (p < 0.004).

CONCLUSIONS

This project has established the expected age limits of spatial vision for monocular and binocular viewing under photopic and high mesopic lighting with both positive and negative contrast optotypes using a single test, which can be implemented either in the clinic or in an occupational setting.

Active Learning to Characterize the Full Contrast Sensitivity Function in Cataracts

Background

To characterize contrast sensitivity function (CSF) in cataractous and pseudophakic eyes compared to healthy control eyes using a novel quantitative CSF test with active learning algorithms.

Methods

This is a prospective observational study at an academic medical center. CSF was measured in eyes with visually significant cataract, at least 2+ nuclear sclerosis (NS) and visual acuity (VA) ≥ 20/50, in pseudophakic eyes and in healthy controls with no more than 1+ NS and no visual complaints, using the Manifold Contrast Vision Meter. Outcomes included Area under the Log CSF (AULCSF) and CS thresholds at 1, 1.5, 3, 6, 12, and 18 cycles per degree (cpd). A subgroup analysis as performed on cataract eyes with VA ≥ 20/25.

Results

A total of 167 eyes were included, 58 eyes in the cataract group, 77 controls, and 32 pseudophakic eyes with respective median AULCSF of 1.053 (0.352) vs 1.228 (0.318) vs 1.256 (0.360). In our multivariate regression model, cataract was associated with significantly reduced AULCSF (P= 0.04, β= −0.11) and contrast threshold at 6 cpd (P= 0.01, β= −0.16) compared to controls. Contrast threshold at 6 cpd was significantly reduced even in the subgroup of cataractous eyes with VA ≥ 20/25 (P=0.02, β=−0.16).

Conclusion

The novel qCSF test detected disproportionate significant contrast deficits at 6 cpd in cataract eyes; this remained significant even in the cataractous eyes with VA ≥ 20/25. CSF testing may enhance cataract evaluation and surgical decision-making, particularly in patients with subjective visual complaints despite good VA.

Self-rated quality of vision and optical phenomena intensity of diffractive presbyopia-correcting IOLs: EDoF, trifocal vs panfocal

PURPOSE

To investigate the self-rated quality of vision (SQV) and optical phenomena intensity of 3 diffractive multifocal intraocular lenses (mIOLs).

SETTING

Department of Ophthalmology, Goethe University Frankfurt, Germany.

DESIGN

Prospective comparative case series.

METHODS

Patients who had bilateral implantation of a diffractive extended depth-of-focus (EDoF), trifocal, or panfocal mIOL were assessed. Outcome parameters were SQV, symptom intensity of optical phenomena under 3 lighting conditions, quality of everyday lifestyle activities, spectacle independence (SI), and contrast sensitivity (CS).

RESULTS

The study comprised 108 eyes. The 3 lenses provided good total SQV under all lighting conditions. EDoF patients reported a slightly better total SQV (EDoF: 9.8 ± 6.67, trifocal: 22.2 ± 7.09, panfocal: 19.6 ± 16.25 visual analog scale, P = .041). A similar percentage of patients reported the presence of optical phenomena with no difference between mIOLs ( P > .05). EDoF, trifocal, and panfocal patients rated symptom intensity of optical phenomena mild to moderate under all lighting conditions; however, EDoF patients reported a lower symptom intensity of halos ( P < .05). Reported quality of everyday lifestyle activities and CS were comparable ( P < .05). All panfocal and trifocal patients (100%) achieved complete SI, whereas almost half (44%) of the EDoF patients used reading spectacles.

CONCLUSIONS

Diffractive EDoF, trifocal, and panfocal mIOLs provided good total SQV with mild to moderate intensity of optical phenomena under all lighting conditions. EDoF patients experienced the same percentage of optical phenomena but reported a weaker symptom intensity of halos and better night-driving ability. EDoF patients would all choose the same IOL, although a significant number of them needed reading spectacles, indicating that SI is not the main factor that determines patient selection of IOLs.

Mesopic Disability Glare in Stage-Two Dysfunctional Lens Syndrome

Introduction

There is a lack of evidence about the exact deterioration of visual function associated with the age-related natural changes in the lens, particularly in intermediate (stage-2) dysfunctional lens syndrome (DLS). Standard photopic visual acuity and contrast sensitivity tests may not show the visual worsening in daily life activities, such as oncoming vehicle headlights at night. The purpose of this study was to analyze visual function under different conditions and glare sources in stage-2 DLS.

Methods

Forty patients over 49 years of age with initial bilateral lens opacification (Lens Opacities Classification System III [LOCS-III] scores up to 3), best-corrected visual acuity of 20/25 or better, and no ocular disease were evaluated. Binocular photopic and mesopic contrast sensitivity (CS) with/without halogen and xenon increasing glare sources were analyzed. Mesopic disability glare (MDG) was calculated as the difference between mesopic CS with/without the glare source.

Results

The median logarithmic CS (logCS) values were lower under mesopic conditions (1.05) than under photopic illumination (1.65; P < 0.001). Halogen and xenon glare further decreased mesopic CS (both, median logCS 0.75, P < 0.001). The mean MDG was 0.31 ± 0.10 log units for halogen glare and 0.33 ± 0.09 log units for xenon glare. The mesopic CS and MDG were not associated with any photopic test. The mesopic CS with glare but not photopic CS or mesopic CS was correlated with the LOCS-III scores. The best association was provided by MDG, which showed a pooled correlation with LOCS-III nuclear opalescence (r = 0.411, P < 0.001) and cortical scores (r = 0.226, P = 0.04).

Conclusion

The mesopic CS under a glare source is an independent early indicator of visual impairment in stage-2 DLS patients, and appears to be substantial. Furthermore, the MDG is more sensitive than photopic and mesopic CS for evaluating patients with initial phacosclerosis. Surgeons should consider this in the decision-making process of the correct timing for lens surgery.

Clinical, Morphological, and Optical Correlates of Visual Function in Patients With Fuchs Endothelial Corneal Dystrophy

PURPOSE

The purpose of this article was to study the clinical, optical, and morphological correlates of visual function in patients with Fuchs endothelial corneal dystrophy (FECD).

METHODS

The case records were analyzed for patients diagnosed with FECD between September 2019 and March 2020. The best-corrected visual acuity (BCVA) was recorded as decimal visual acuity and converted to the logarithm of the minimum angle of resolution units. Contrast sensitivity was measured with the Pelli-Robson contrast sensitivity test. Corneal alterations, including central corneal thickness, depression of the posterior cornea, and corneal densitometry values, were evaluated using Scheimpflug images. Corneal epithelial thickness was measured by spectral-domain optical coherence tomography.

RESULTS

A total of 107 eyes of 61 patients (18 male and 43 female) with FECD were retrospectively investigated. The Spearman rank correlation coefficient showed moderate correlation between BCVA and contrast sensitivity (ρ = -0.66, P < 0.001), with some patients maintaining relatively good BCVA but having reduced contrast sensitivity. Logistic regression analysis demonstrated that age, central corneal thickness, depression of the posterior cornea, and epithelial thickening were negatively associated with contrast sensitivity but not with BCVA.

CONCLUSIONS

Contrast sensitivity is a useful tool for assessing visual dysfunction and should be incorporated into the assessment protocol of patients with FECD. Alterations in the cornea, including central corneal thickness, depression of the posterior cornea, and epithelial thickening, might be objective parameters that can help the clinician in grading the severity of the disease and tracking its progression.

Effect of red ginseng on visual function and vision-related quality of life in patients with glaucoma

Background

Red ginseng has been found to improve ocular perfusion and dry eye syndrome in glaucomatous eyes; however, its effects on visual function and vision-related quality of life have not been investigated. This study sought to evaluate the effects of red ginseng on visual function and vision-related quality of life in glaucoma patients using contrast sensitivity and a questionnaire.

Methods

Participants were randomly assigned to two groups in this prospective, randomized, double-blind study: in one group, red ginseng was taken first, followed by a placebo, and in the other, placebo was taken first, followed by red ginseng. We measured and compared changes in contrast sensitivity and vision-related quality of life between the two groups. Contrast sensitivity was measured using OPTEC® 6500P, and vision-related quality of life was evaluated using the 25-item National Eye Institute Visual Function Questionnaire. One-way and two-way repeated measure analyses of variance were used for the comparison. Relationships between respective changes in dry eye syndrome and contrast sensitivity were also analyzed.

Results

Daytime contrast sensitivity and ocular pain improved after the administration of red ginseng. Nighttime contrast sensitivity was improved in early or moderate glaucoma. Improved contrast sensitivity was not associated with improvement in dry eye syndrome.

Conclusion

Red ginseng could improve contrast sensitivity and ocular pain in patients with glaucoma. The mechanism underlying improvement in contrast sensitivity appears to be associated with enhanced retinal perfusion or retinal ganglion cell function, but not dry eye syndrome.

Hierarchical Bayesian modeling of contrast sensitivity functions in a within-subject design

Recent development of the quick contrast sensitivity function (qCSF) method has made it possible to obtain accurate, precise, and efficient contrast sensitivity function (CSF) assessment. To improve statistical inference on CSF changes in a within-subject design, we developed a hierarchical Bayesian model (HBM) to compute the joint distribution of CSF parameters and hyperparameters at test, subject, and population levels, utilizing information within- and between-subjects and experimental conditions. We evaluated the performance of the HBM relative to a non-hierarchical Bayesian inference procedure (BIP) on an existing CSF dataset of 112 subjects obtained with the qCSF method in three luminance conditions (Hou, Lesmes, Kim, Gu, Pitt, Myung, & Lu, 2016). We found that the average d's of the area under log CSF (AULCSF) and CSF parameters between pairs of luminance conditions at the test-level from the HBM were 33.5% and 103.3% greater than those from the BIP analysis of AULCSF. The increased d' resulted in greater statistical differences between experimental conditions across subjects. In addition, simulations showed that the HBM generated accurate and precise CSF parameter estimates. These results have strong implications for the application of HBM in clinical trials and patient care.

Non-diffractive wavefront shaping extended depth of focus (EDoF) intraocular lens: visual performance and patient-reported outcome

PURPOSE

To evaluate visual performance and patient-reported outcomes after bilateral implantation of new non-diffractive wavefront shaping extended depth of focus (EDOF) intraocular lens (IOL).

SETTING

Department of Ophthalmology, Goethe University, Frankfurt, Germany.

DESIGN

Prospective, single-arm, single-center study.

METHODS

Patient population: We included 16 patients (32 eyes) who received bilateral implantation of a non-diffractive wavefront shaping EDOF IOL (AcrySof® IQ Vivity®, Alcon Research, TX, USA). Target refraction in both eyes was emmetropia. Observation procedure: Monocular and binocular uncorrected (UCVA) and distance-corrected (DCVA) visual acuity (VA), refractive outcome, defocus curve, contrast sensitivity (CS) were evaluated 3 months after surgery with a questionnaire on optical phenomena and spectacle independence. Main Outcome measure: Three months postoperative monocular and binocular UCVA and DCVA (logMAR); defocus curve; CS; and quality of vision (QoV) questionnaire results.

RESULTS

Mean spherical equivalent was -0.16 ± 0.37 D 3 month postoperatively. Binocular UDVA at distance, intermediate, and near was 0.01 ± 0.05 logMAR at 4m, 0.05 ± 0.05 logMAR at 80cm, 0.07 ± 0.06 logMAR at 66cm, and 0.25 ± 0.11 logMAR at 40cm, respectively. Despite some minor optical phenomena, 88% of patients would choose the same lens. 63% of patients reported no optical phenomena at all. Contrast sensitivity was 1.25 ± 0.41 logCS (photopic), 0.96 ± 0.24 logCS (mesopic) and 0.93 ± 0.24 (mesopic + glare).

CONCLUSIONS

This non-diffractive wavefront shaping EDOF IOL provides good VA at far and intermediate distance and functional near VA. It showed good QoV and CS, and high spectacle independence for distance and intermediate vision with significantly less optical phenomena than with other EDOF or MIOLs.

Test-retest Repeatability of the Ohio Contrast Cards

SIGNIFICANCE

The Ohio Contrast Cards are a repeatable test of contrast sensitivity, and they reveal higher contrast sensitivity for low-vision patients than is shown by the Pelli-Robson chart.

PURPOSE

This study aimed to compare the contrast sensitivity results and test/retest ±limits of agreement for the Ohio Contrast Cards and the Pelli-Robson letter contrast sensitivity chart on two challenging groups of participants, and to compare the Ohio Contrast Card results with grating acuity and the Pelli-Robson results with letter acuity.

METHODS

The Ohio Contrast Card and Pelli-Robson tests were each performed twice by two different examiners within one visit on 40 elder patients in Primary Vision Care (>65 years old) and 23 to 27 low-vision school-aged students. Grating acuity was measured using the Teller Acuity Cards (all participants), and letter acuity was measured using ClearChart (elders) or the Bailey-Lovie chart (students).

RESULTS

The ±95% limits of agreement were similar for the Ohio Contrast Cards and the Pelli-Robson chart. The elders' limits of agreement were ±0.27 (Ohio Contrast Cards) and ±0.28 (Pelli-Robson); the students' limits of agreement were ±0.42 (Ohio Contrast Cards) and ±0.51 (Pelli-Robson). However, Ohio Contrast Card results were 0.41 log10 Michelson units more sensitive than the Pelli-Robson chart (over one line on the Pelli-Robson chart) for the elders and 0.90 log10 Michelson units (three lines on the Pelli-Robson chart) more sensitive for the elders (0.11 and 0.6 log10 Weber units, respectively). The Pelli-Robson results were correlated with letter acuities and Ohio Contrast Card results for both groups, and the Ohio Contrast Card results were correlated with Teller Acuity Card acuities for the elders.

CONCLUSIONS

The Ohio Contrast Cards and Pelli-Robson chart are similarly repeatable. Both contrast sensitivity tests can provide additional clinical information that is not available through visual acuity testing, and Ohio Contrast Card may provide additional information not available from the Pelli-Robson chart.

Presbyopia Correction in Astigmatic Eyes Using a Toric Trifocal Intraocular Lens With Quadrifocal Technology

PURPOSE

To evaluate the visual performance after bilateral implantation of a toric diffractive aspheric multifocal intraocular lens (IOL) with a +2.17 diopters (D) (60 cm) intermediate and a +3.25 D (40 cm) addition (add) power.

METHODS

This prospective single-arm study was conducted at the Department of Ophthalmology, Goethe University, Frankfurt, Germany. Twenty-five patients (50 eyes) received bilateral implantation of the toric PanOptix IOL (AcrySof IQ PanOptix; Alcon Research LLC) before enrollment. Exclusion criteria were previous ocular surgeries excluding lens surgery and ocular pathologies or corneal abnormalities. Examination at 3 months postoperatively included manifest refraction; monocular and binocular uncorrected distance (UDVA) and distance-corrected (DCVA) visual acuity at 4 m and 80, 60, and 40 cm; and slit-lamp examination. At 3 months postoperatively, monocular and binocular defocus, binocular contrast sensitivity under photopic and mesopic conditions, and optical phenomena, and spectacle independence were evaluated.

RESULTS

Mean refractive spherical equivalent was 0.12 ± 0.380 D and mean refractive cylinder was -0.21 ± 0.237 D at 3 months postoperatively. A significant decrease in refractive cylinder was observed postoperatively (P < .05), with 98% showing a postoperative astigmatism below 0.75 D. Monocular UDVA was better than 0.14 logMAR in all distances. Binocular defocus curve showed peaks at 0.00 D (-0.09 logMAR) and -1.50 and -2.00 D (-0.02 and 0.00 logMAR). The worst values between far (4 m) and near (40 cm) distance were 0.04 logMAR at -1.00 D. Despite some optical phenomena, 92% of patients would choose the same IOL again and recommend it to others.

CONCLUSIONS

The visual performance of the toric PanOptix IOL showed good visual acuity at all distances; more than 90% achieved a decrease of refractive cylinder below 0.75 D, high patient satisfaction despite some optical phenomena, and high spectacle independence 3 months postoperatively. [J Refract Surg. 2020;36(10):638-644.].

A Systematic Review of Carotenoids in the Management of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) remains a leading cause of modifiable vision loss in older adults. Chronic oxidative injury and compromised antioxidant defenses represent essential drivers in the development of retinal neurodegeneration. Overwhelming free radical species formation results in mitochondrial dysfunction, as well as cellular and metabolic imbalance, which becomes exacerbated with increasing age. Thus, the depletion of systemic antioxidant capacity further proliferates oxidative stress in AMD-affected eyes, resulting in loss of photoreceptors, neuroinflammation, and ultimately atrophy within the retinal tissue. The aim of this systematic review is to examine the neuroprotective potential of the xanthophyll carotenoids lutein, zeaxanthin, and meso-zeaxanthin on retinal neurodegeneration for the purpose of adjunctive nutraceutical strategy in the management of AMD. A comprehensive literature review was performed to retrieve 55 eligible publications, using four database searches from PubMed, Embase, Cochrane Library, and the Web of Science. Epidemiology studies indicated an enhanced risk reduction against late AMD with greater dietary consumption of carotenoids, meanwhile greater concentrations in macular pigment demonstrated significant improvements in visual function among AMD patients. Collectively, evidence strongly suggests that carotenoid vitamin therapies offer remarkable synergic protection in the neurosensory retina, with the potential to serve as adjunctive nutraceutical therapy in the management of established AMD, albeit these benefits may vary among different stages of disease.

Impact on binocular visual function of small-incision lenticule extraction for high myopia

PURPOSE

To assess whether small-incision lenticule extraction (SMILE) for high myopia reduces the binocular visual function assessed by stereoacuity, binocular visual acuity, binocular contrast sensitivity, and binocular summation.

SETTING

University hospital.

DESIGN

Prospective case series.

METHODS

Patients with a myopic spherical equivalent of at least 6.00 diopters (D) scheduled for SMILE aimed at emmetropia were included. Psychophysical testing was performed with correction preoperatively but no correction postoperatively. Stereoacuity was assessed with the Randot Circles test and the near Frisby test, visual acuity (monocular and binocular) was assessed with high-contrast Early Treatment Diabetic Retinopathy Study charts, and contrast sensitivity (monocular and binocular) was assessed with the Pelli-Robson chart and the Freiburg Acuity and Contrast Test. Binocular summation was calculated by comparing the binocular score against the best monocular score.

RESULTS

A total of 138 eyes of 69 patients were included. The mean spherical equivalent changed from -7.46 D ± 1.06 (SD) to -0.23 D ± 0.40 postoperatively. Stereoacuity did not change significantly postoperatively; median change (interquartile range) was -0.32 (-6.21 to 1.55) seconds of arc with the Frisby test and 0.00 (-7.5 to 5.0) seconds of arc with the Randot test (P ≥ .06). Binocular postoperative uncorrected distance visual acuity was not different from the preoperative corrected distance visual acuity (P = .40). Contrast sensitivity declined slightly monocularly with both tests of contrast sensitivity but was unaltered binocularly (P ≥ .08). Binocular summation for visual acuity and contrast sensitivity was unaltered following surgery (P ≥ .09).

CONCLUSIONS

SMILE for high myopia did not reduce the binocular function assessed by stereoacuity, binocular visual acuity, binocular contrast sensitivity, and binocular summation.

Visual image quality after small-incision lenticule extraction compared with that of spectacles and contact lenses

PURPOSE

To assess the influence of small-incision lenticule extraction (SMILE) for high myopia on the visual image quality assessed by the logarithm of the visual Strehl ratio (logVSX) and put this into a clinical context by pairwise comparing the logVSX of postoperative eyes with those of myopic controls wearing spectacles and/or contact lenses.

SETTING

University hospital.

DESIGN

Prospective and cross-sectional clinical study.

METHODS

Patients with a myopic spherical equivalent of at least 6.00 diopters treated with SMILE aimed at emmetropia and correspondingly myopic controls corrected with spectacles and/or contact lenses were included. The logVSX calculation was divided into habitual logVSX based on the wavefront aberration measurement directly and optimal logVSX calculated in a theoretical through-focus experiment to obtain the best-achievable logVSX.

RESULTS

A total of 117 eyes of 61 patients and 64 eyes of 34 myopic controls were included. SMILE did not affect the habitual logVSX but worsened the optimal logVSX (P < .001). The postoperative habitual logVSX was statistically significantly worse compared with contact lenses (P = .002). The postoperative optimal logVSX was significantly worse compared with both spectacles (P < .01) and contact lenses (P = .003). There was no statistically significant difference in habitual or optimal logVSX between spectacles and contact lenses.

CONCLUSIONS

SMILE for high myopia does not affect the habitual logVSX but decreases the optimal logVSX slightly. The postoperative habitual logVSX is worse than for contact lenses but not spectacles, and the postoperative optimal logVSX is worse than for both contact lenses and spectacles. There is no statistically significant difference in either habitual or optimal logVSX between spectacles and contact lenses.

Measuring Contrast Sensitivity Function With Active Learning in Retinal Vein Occlusion: A New Endpoint of Visual Function

BACKGROUND AND OBJECTIVE

To characterize contrast sensitivity function (CSF) in patients with retinal vein occlusion (RVO) compared to age-matched controls using novel computerized contrast sensitivity (CS) testing with active learning algorithms.

PATIENTS AND METHODS

CSF was prospectively measured in RVO patients with visual acuity (VA) greater than 20/200 and age-matched controls using the novel Manifold Contrast Vision Meter implementing quantitative CSF testing. Outcomes included area under the Log CSF (AULCSF), contrast acuity (CA), and CS thresholds at 1, 1.5, 3, 12, and 18 cycles per degree (cpd). A sub-analysis was performed on RVO eyes with good acuity (VA ≥ 20/30).

RESULTS

Twenty-two eyes with RVO and 63 control eyes were included. Mean AULCSF (± standard deviation) in RVO eyes was 0.817 (0.28) compared to 1.217 (0.28) in controls (P < .0001). Mean contrast acuity in the RVO group was 1.054 (0.19) versus 1.286 ± 0.16 in controls (P < .0001). For individual spatial frequencies, CS loss at 6.0 cpd was most prominent in the RVO group. In 10 RVO eyes with VA of 20/30 or greater, mean AULCSF was 0.978 versus 1.217 in control eyes. (P = .008).

CONCLUSIONS

CSF in eyes with RVO was found to be significantly reduced compared to age-matched controls. CSF seems to be a promising visual function endpoint with potential applications in clinical practice and future clinical trials. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:392-400.].

Measurement of individual differences in face-identity processing abilities in older adults

BACKGROUND

Face-identity processing declines with age. Few studies have examined whether face-identity processing abilities can be measured independently from general cognitive abilities in older adults (OA). This question has practical implications for the assessment of face-identity processing abilities in OA and theoretical implications for the notion of face processing as a specific ability. The present study examined the specificity of face memory and face matching abilities in OA aged 50 + .

METHODS

Performance of younger adults (YA) and OA was measured on face tasks: Cambridge Face Memory Task (CFMT), the Glasgow Face Matching Task (GFMT), holistic processing; and tasks of general cognition: fluid intelligence, selective attention, and mental rotation. Data were analyzed using multiple regression models encompassing (i) the CFMT/GFMT and measures of general cognition; and (ii) all face processing tasks.

RESULTS

Across the two age groups, models encompassing all face tasks were significant and accounted for more variance in the data than models encompassing the CFMT/GFMT and measures of general cognition. General cognitive abilities accounted for 17% of variance for the GFMT (p < 0.01) and 3% for the CFMT (p > 0.05).

DISCUSSION

Our results suggest that face memory can be measured independently from general cognition using the CFMT in OA. Implications for the notion of a general face processing factor across the adult lifespan are discussed.

Effect of Wavefront Aberrations on Night Vision Problems and Mesopic Contrast Threshold After SMILE

PURPOSE

To investigate the effect of wavefront aberrations on night vision problems and mesopic contrast threshold after small incision lenticule extraction (SMILE).

METHODS

Forty-two participants (84 eyes) who underwent SMILE were included in this prospective observational study. Visual outcomes including uncorrected distance visual acuity (UDVA), subjective manifest refraction, mesopic contrast threshold (Binoptometer 4P; Oculus Optikgeräte GmbH), and higher order aberrations (HOAs) were analyzed before and 3 months after surgery. The patient's night vision satisfaction was assessed using a questionnaire.

RESULTS

The mean spherical equivalent was -5.30 ± 1.38 diopters (D) preoperatively and -0.06 ± 0.15 D postoperatively. UDVA was better than 20/20 in 98.81% of the patients and better than 20/25 in all patients. Scores of night vision satisfaction and glare changed significantly in the postoperative period (F = 8.463, P = .001; F = 69.518, P < .001, respectively). Preoperative spherical diopters (lower order aberrations) were positively correlated with night vision satisfaction (r = -0.329, P = .041) and glare score (r =-0.332, P = .039). Age (odds ratio [OR] = 1.272, 95% CI = 1.019 to 1.589) and preoperative spherical diopter (OR = 0.437, 95% CI = 0.199 to 0.975) were correlated with night vision satisfaction scores by analysis of binary regression. The root mean square value of total HOAs increased 3 months after surgery (t = -6.873, P < .001) with an increase in horizontal coma (Z₃¹) and spherical aberration (Z₄⁰) (P < .001). No correlation was observed between glare score and HOAs; however, patients with higher preoperative myopia demonstrated continuously decreasing contrast under mesopic conditions and higher postoperative horizontal coma.

CONCLUSIONS

Myopic patients with higher preoperative spherical errors experienced more glare at night after SMILE surgery. Postoperative horizontal coma was associated with worse mesopic contrast thresholds. [J Refract Surg. 2021;37(7):446-452.].

Active Learning of Contrast Sensitivity to Assess Visual Function in Macula-off Retinal Detachment

PURPOSE

To characterize the contrast sensitivity function (CSF) in patients with successful repair of macula-off rhegmatogenous retinal detachment (RD) using an adaptive computerized contrast testing device.

METHODS

CSF was prospectively measured in macula-off RD patients following successful repair and age-matched controls at W. K. Kellogg Eye Center and Massachusetts Eye and Ear, employing the active learning device Manifold Contrast Vision Meter (Adaptive Sensory Technology, San Diego, CA). Outcome measures included average area under the CSF curve (AULCSF), CS thresholds at 1-18 cycles per degree (cpd) and best correctd visual acuity (BCVA) in RD eyes fellow eyes and controls. A sub-analysis was performed in eyes with BCVA of 20/30 or better.

RESULTS

Twenty-three macula-off RD eyes status post repair, fellow healthy eyes and 45 age-matched control eyes underwent CSF testing. The mean BCVA of the 23 RD eyes was 0.250 logMAR, significantly reduced compared to fellow eyes 0.032 (p<0.001) and controls 0.026 (p< 0.00001). There was a statistically significant reduction in AULCSF in RD eyes compared to the fellow eyes (p<0.0001) and to age-matched controls (Z-score -0.90, p<0.0001) and CSF reduction across all spatial frequencies. In the 15 RD eyes with BCVA of 20/30 or better, the mean CSF was significantly reduced compared to fellow eyes (p=0.0158) and controls (p=0.0453).

CONCLUSIONS

CSF in macula-off RD eyes following repair was significantly reduced compared to fellow eyes and age-matched controls. CSF seems to be a promising visual function endpoint with potential applications in the clinical practice and future clinical trials.

Measuring the Contrast Sensitivity Function in Non-Neovascular and Neovascular Age-Related Macular Degeneration: The Quantitative Contrast Sensitivity Function Test

Age-related macular degeneration (AMD) affects various aspects of visual function compromising patients' functional vision and quality of life. Compared to visual acuity, contrast sensitivity correlates better with vision-related quality of life and subjectively perceived visual impairment. It may also be affected earlier in the course of AMD than visual acuity. However, lengthy testing times, coarse sampling and resolution, and poor test-retest reliability of the existing contrast testing methods have limited its widespread adoption into routine clinical practice. Using active learning principles, the qCSF can efficiently measure contrast sensitivity across multiple spatial frequencies with both high sensitivity in detecting subtle changes in visual function and robust test-retest reliability, emerging as a promising visual function endpoint in AMD both in clinical practice and future clinical trials.

Sensitivity and Stability of Functional Vision Tests in Detecting Subtle Changes Under Multiple Simulated Conditions

Purpose

To explore whether subtle changes in visual quality can be detected using different measures of visual function against the quick contrast sensitivity function test (quick CSF).

Methods

Sixty participants, aged 17 to 34 years, were enrolled. Participants' vision was degraded by 0.25 D undercorrection (0.25 D), 60% neutral density filter brightness reduction (60% ND), and 0.8 Bangerter foil optical diffusion (0.8BAN). Visual function tests including visual acuity and contrast sensitivity (CSV-1000E and quick CSF) were measured with participant's best-corrected vision and under simulated visual degradation conditions. Test sensitivities in detecting differences were compared.

Results

Statistically significant visual acuity degradation was observed in the 0.8BAN condition only (Pcorrected < 0.001). With CSV-1000E and outliers removed, significant CS degradation was observed in all spatial frequencies, area under log CSF (AULCSF) in the 0.8BAN condition (Pcorrected < 0.001 for all), medium and high spatial frequencies and AULCSF in the 60%ND condition (Pcorrected,6cpd = 0.002, Pcorrected,12cpd = 0.005, Pcorrected,18cpd = 0.001, Pcorrected,AULCSF < 0.001) and the 0.25 D condition (Pcorrected,6cpd = 0.011, Pcorrected,12cpd = 0.013, Pcorrected,18cpd = 0.015, Pcorrected,AULCSF < 0.001). With the quick CSF, significant CS degradation was observed in all simulated visual conditions in all spatial frequencies, cutoff frequency and AULCSF (Pcorrected < 0.001 for all). Test-retest reliability of the quick CSF method was high; coefficient of repeatability ranged from 0.14 to 0.18 logCS.

Conclusions

Compared with visual acuity and chart-based CS tests, the quick CSF method provided more reliable and sensitive measures to detect small visual changes.

Translational Relevance

The quick CSF method can provide sensitive and reliable measures to monitor disease progression and assess treatment outcomes.

Quality of Vision Following LASIK and PRK-MMC for Treatment of Myopia

INTRODUCTION

Femtosecond-assisted thin flap, laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy with mitomycin-C (PRK-MMC) are the two most common refractive surgical procedures used to enhance visual capability in the U.S military. The purposes of the study were to examine effects on quality of vision following LASIK and PRK-MMC using a novel computer-based quick contrast sensitivity function (qCSF) test.

MATERIALS AND METHODS

This prospective clinical study included 58 active duty U.S. military service members who elected LASIK (n = 29) or PRK-MMC (n = 29) refractive surgery for myopia (nearsightedness) treatment. Monocular photopic and mesopic quality of vision of the right eyes in spectacle correction preoperatively and unaided right eyes at four postoperative follow-up visits (1 week, 2 weeks, 1 month, and 3 months) were examined using the qCSF device. Two qCSF parameters, area under a log CSF (AULCSF) between 1.5 and 18 cycles per degree, and CSF cutoff acuity (CSF Acuity), were collected using a 50-trial setting at a 4-m testing distance. General linear model (GLM) Repeated-measures Analysis of Covariance was used to examine effects on quality of vision following LASIK and PRK-MMC. Post hoc testing with Bonferroni correction was used for pairwise comparisons, and preoperative cylinder refraction was used as a covariate. Two-tailed independent t-test was used to compare preoperative and postoperative parameters between LASIK and PRK-MMC. Pearson's correlation, Bland-Altman plots, and multiple linear regression were used to examine the relationship among the qCSF and other vision tests.

RESULTS

Quality of vision, AULCSF, and CSF Acuity returned to the preoperative baseline at postoperative 2 weeks under mesopic condition and at postoperative 1 month under photopic condition after PRK-MMC. In comparison, photopic and mesopic quality of vision were not significantly different from the baseline at any of the four postoperative visits following LASIK. Changes of CSF Acuity from the baseline after LASIK were significantly better under photopic than mesopic condition by 0.067 ± 0.014 logarithm of the minimum angle of resolution (logMAR); P < .001). Quality of vision was not significantly different between the LASIK and PRK-MMC groups at postoperative 1 and 3 months. When predicting photopic AULCSF (overall model fit R2 = 0.47), 5% contrast acuity (beta = -0.43), visual acuity in 100% contrast (beta = -0.18), and residual refraction in spherical equivalent (beta = 0.20) were significant predictors (P ≤ .001), while high-order aberrations (beta = -0.07, P = .22) were not significant predictors. Visual acuity (beta = -0.12, P = .07) and high-order aberrations (beta = -0.04, P = .58) were not significant predictors of mesopic AULCSF. Bland-Altman plots show that photopic CSF Acuity and visual acuity had a mean difference of 0.19 ± 0.01 logMAR with limits of agreement (LOAs) at -0.01 and 0.39 logMAR. Photopic CSF Acuity and 5% contrast acuity had a mean difference of -0.06 ± 0.01 logMAR with LOAs at -0.33 and 0.21 logMAR.

CONCLUSION

Quality of vision recovers at postoperative 1 week after LASIK and at postoperative 1 month after PRK-MMC. The standard black-on-white high-contrast, chart-based visual acuity test is weak in predicting quality of vision. The qCSF detects mild-to-moderate visual changes and is suitable for quality of vision assessment following refractive eye surgery.

Contrast sensitivity function in patients with macular disease and good visual acuity

INTRODUCTION

Contrast sensitivity function (CSF) may better estimate a patient's visual function compared with visual acuity (VA). Our study evaluates the quick CSF (qCSF) method to measure visual function in eyes with macular disease and good letter acuity.

METHODS

Patients with maculopathies (retinal vein occlusion, macula-off retinal detachment, dry age-related macular degeneration and wet age-related macular degeneration) and good letter acuity (VA ≥20/30) were included. The qCSF method uses an intelligent algorithm to measure CSF across multiple spatial frequencies. All maculopathy eyes combined and individual macular disease groups were compared with healthy control eyes. Main outcomes included area under the log CSF (AULCSF) and six CS thresholds ranging from 1 cycle per degree (cpd) to 18 cpd.

RESULTS

151 eyes with maculopathy and 93 control eyes with VA ≥20/30 were included. The presence of a maculopathy was associated with significant reduction in AULCSF (β: -0.174; p<0.001) and CS thresholds at all spatial frequencies except for 18 cpd (β: -0.094 to -0.200 log CS, all p<0.01) compared with controls. Reductions in CS thresholds were most notable at low and intermediate spatial frequencies (1.5 cpd, 3 cpd and 6 cpd).

CONCLUSION

CSF measured with the qCSF active learning method was found to be significantly reduced in eyes affected by macular disease despite good VA compared with healthy control eyes. The qCSF method is a promising clinical tool to quantify subtle visual deficits that may otherwise go unrecognised by current testing methods.

Disorganisation of retinal inner layers is associated with reduced contrast sensitivity in retinal vein occlusion

BACKGROUND/AIMS

To determine if disorganisation of retinal inner layers (DRIL) is associated with reduced contrast sensitivity (CS) in patients with retinal vein occlusion (RVO) with a history of macular oedema (ME).

METHODS

Prospective, observational cohort study. Patients with a history of ME secondary to central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO) from October 2017 to July 2019 at a single institution were included. Patients underwent complete ophthalmic examination, spectral domain optical coherence tomography (SD-OCT) and CS testing using the quick contrast sensitivity function (qCSF) method. Eyes with coexisting macular disease were excluded. SD-OCT images were analysed for presence and extent of DRIL, intraretinal fluid (IRF), subretinal fluid (SRF), hyperreflective foci, epiretinal membrane (ERM), external limiting membrane (ELM) disruption, ellipsoid zone (EZ) disruption, central macular thickness (CMT) and central foveal thickness (CFT). Multivariable mixed-effect linear regressions were performed for the area under the log contrast sensitivity function (AULCSF) using Stata (StataCorp). P values <0.05 were considered significant.

RESULTS

58 visits from 31 patients were included (1.9±1.2 visits per patient). 29 (50%) were for CRVO. The average age was 63.9±10.5 years. On multivariable analysis, DRIL extent (p<0.001), CMT (p=0.007), CFT (p=0.024) and moderate cataract (p=0.001) were significantly associated with worse AULCSF.

CONCLUSIONS

DRIL extent is associated with reduced CS in eyes with ME secondary to RVO. DRIL is an imaging feature that has important implications for visual function.

Contrast Sensitivity Testing in Retinal Vein Occlusion Using a Novel Stimulus

Purpose

This study evaluated a novel tool known as the motion diamond stimulus (MDS), which utilizes contrast-generated illusory motion in dynamic test regions to determine contrast sensitivity (CS).

Methods

Patients with treated unilateral retinal vein occlusions (RVOs) underwent three assessments: the MDS, the Pelli-Robson (PR), and the National Eye Institute's Visual Function Questionnaire (VFQ-25). The MDS assessment produced two data end points, α and β. The α value represents the overall contrast threshold level and the β value serves to quantify the adaptability of the visual contrast system. The CS parameters from the MDS and log CS PR output values were used to compare RVO eyes (n = 20) to control eyes (n = 20).

Results

The study participants had a mean composite VFQ-25 score of 89.5 ± 10.4 on the VFQ-25. A significant difference was observed between the RVO eyes and the control eyes in PR log CS scores (P value = 0.0001) and in MDS α value (P value = 0.01). No difference in MDS β value was found between the study groups (P value = 0.39).

Conclusions

The results for the MDS assessment's α parameter corroborated the PR scores, suggesting contrast sensitivity threshold impairment in patients with RVO. No significant difference in β value was observed, suggesting that adaptability of the visual system is maintained in treated RVO eyes.

Translational Relevance

Currently, visual complaints cannot be entirely identified by Snellen visual acuity alone. The MDS offers potentially a more complete look at visual function, by including contrast sensitivity and may be able to quantify changes otherwise overlooked in retinal disease progression.

Comparison of two extended depth of focus intraocular lenses with a monofocal lens: a multi-centre randomised trial

Purpose

The AT LARA 829MP is a next-generation extended depth of focus (EDOF) intraocular lens (IOL) providing continuous vision over a range of distances. The aim of this prospective multi-centre randomised trial was to compare two EDOF IOLs and one monofocal IOL.

Methods

Cataract patients between 50 and 80 years were randomised for bilateral implantation with either the AT LARA 829MP (EDOF), the TECNIS Symfony (EDOF) or the CT ASPHINA 409MP (monofocal). Follow-up was at 1 to 2 weeks, 1 month and 4 to 6 months.

Results

A total of 211 patients were randomised and included in the final analysis. Monocular depth of focus was significantly better for AT LARA 829MP eyes compared with that for TECNIS Symfony at all thresholds (p = 0.024, 0.001 and 0.006, for 0.1, 0.2 and 0.3 logMAR respectively) with no significant difference for binocular depth of focus. LARA eyes had significantly better monocular depth of focus at all levels compared with ASPHINA eyes (all p < 0.0001), while there was no significant difference between Symfony and ASPHINA eyes at 0.1 logMAR and 0.2 logMAR. Both EDOF IOLs were significantly better than the monofocal ASPHINA at all levels for binocular depth of focus (LARA: all p < 0.0001; Symfony: all p = 0.002). Distance visual acuity was similar for all IOLs at 6 months; intermediate and near visual acuity were significantly better for the EDOF IOLs than for the monofocal (p < 0.0001). Refraction improved in all groups relative to baseline. Contrast sensitivity was higher with the CT ASPHINA 409MP but both EDOF lenses had a better spectacle independence rate. At 6 months, all IOLs were well centred with no cases of tilt. No general safety issues were raised for any of the groups.

Conclusion

The two EDOF intraocular lenses investigated provided good visual outcomes with comparable visual acuity at all distances. The AT LARA 829MP provided the widest monocular depth of focus at 0.1 and 0.2 logMAR, with a clear superiority compared with the monofocal IOL. TECNIS Symfony was superior to the monofocal control at 0.3 logMAR. Spectacle independence and patient satisfaction were comparable.

Trial registration

Trial registered on https://clinicaltrials.gov/ under the identification NCT03172351 (date of registration 1 June May 2017).

Contrast sensitivity and retinal straylight after alcohol consumption: effects on driving performance

In this study, we aimed to investigate the effects of alcohol intake on visual function and driving performance, as well as on the relationship between these. A total of 40 healthy participants took part in three experimental sessions: one baseline session and two further sessions after consuming two different quantities of alcohol (300 ml and 450 ml of red wine). The breath alcohol content (BrAC) was measured using a breath analyzer. The contrast sensitivity and retinal straylight due to the forward intraocular scattering were measured to characterize visual function, and driving performance was assessed in three different scenarios using a driving simulator. The results showed a deterioration in contrast sensitivity and retinal straylight after drinking alcohol, in addition to an impaired ability to drive, especially for the highest alcohol intake. We also observed that the deteriorated driving performance was a function of the contrast sensitivity and retinal straylight under the effects of alcohol, indicating that these visual variables can partially predict driving performance in these conditions.

Effect of age and refractive error on quick contrast sensitivity function in Chinese adults: a pilot study

PURPOSE

To evaluate the potential effect of age and refractive error on visual acuity (VA) performance and quick contrast sensitivity function (qCSF) in normal Chinese adults.

METHOD

Ninety-two subjects with normal best corrected distance VA (BCDVA) were enrolled in this pilot study. Measurements included BCDVA, best corrected near VA (BCNVA), unaided VA (UNVA), habitual spectacle-corrected near VA (SCNVA) and qCSF. For analyses, subjects were categorized into three age groups (20~40 years, 41~60 year and >60 years) and four refractive groups (hyperopia, emmetropia, myopia and high myopia). Relationships between age, refractive error, types of VA and qCSF were tested using simple and multiple linear regressions analyses.

RESULT

Mean age and refractive error of the study participants were 44.04 ± 12.68 years and -1.86 ± 2.91D, respectively. Among the stratified age groups, a hyperopic shift of refraction (-3.24 ± 2.88D vs. -1.24 ± 2.64D vs. 0.39 ± 1.42D, respectively; P < 0.001) and a reduction in BCNVA (P = 0.014), SCNVA (P < 0.001) and cut-off spatial frequency (SF) (P = 0.032) were found with increasing age. Among the four refractive groups, the SCNVA and cut-off SF of hyperopia were worse compared to the other refractive statuses (all P < 0.05). Age was significantly associated with cut-off SF (standardized β = -0.29, P = 0.005) after adjustment for SER, gender and all types of VA.

CONCLUSION

For normal Chinese adults with normal BCDVA, age was the main factor associated with CSF, which may be independent of refractive error.

Improvement or Worsening of Human Contrast Sensitivity Due to Blue Light Attenuation at 450 nm

PURPOSE

The work was aimed at comparing contrast sensitivity performance in an indoor environment with two filters, which differ only in the presence of a band at 450±20 nm in the transmittance spectrum.

PATIENTS AND METHODS

Thirty-nine subjects participated. The filters were the Standard (ST) and Professional (PRO) Drive lenses (Hoya, Japan), the latter showing the attenuation band at 450 nm. Photopic contrast sensitivity (CS) was measured at different spatial frequencies from 1.5 to 18 cpd through Functional Acuity Contrast Test with both lenses (LogCS_ST and LogCS_PRO, respectively). The areas under the curves of LogCS_ST and LogCS_PRO as a function of the spatial frequency were also considered.

RESULTS

In the range of the measured values of LogCS_ST for the thirty-nine participants, at each spatial frequency and also for the areas, the difference Δ = LogCS_PRO - LogCS_ST was found to decrease and change sign from positive to negative as a function of LogCS_ST, thus allowing to deduce a threshold (LogCS_threshold) for LogCS_ST corresponding to Δ=0. Significant CS worsening was found with the PRO compared to the ST lens for the subjects showing LogCS_ST > LogCS_threshold. Vice versa, CS improvement was found when LogCS_ST < LogCS_threshold.

CONCLUSION

In the choice of a blue-filtering lens, practitioners should take into consideration that the attenuation of light in the range 420-470 nm is expected to produce a CS worsening in subjects showing a relatively high initial CS (higher than a threshold CS). For these subjects, the general reduction of transmitted light intensity prevails on possible advantages. On the contrary, subjects showing a relatively low initial CS are expected to show a CS improvement because the attenuation of light in the range 420-470 nm is expected to reduce intraocular scattering and to mimic the effect as an optical filter of the human macular pigment, advantages which prevail on the reduction of the transmitted light intensity.

Habitual higher order aberrations affect Landolt but not Vernier acuity

To assess whether the eye's optical imperfections are relevant for hyperacute vision, we measured ocular wave aberrations, visual hyperacuity, and acuity thresholds in 31 eyes of young adults. Although there was a significant positive correlation between the subjects' performance in Vernier- and Landolt-optotype acuity tasks, we found clear differences in how far both acuity measures correlate with the eyes' optics. Landolt acuity thresholds were significantly better in eyes with low higher order aberrations and high visual Strehl ratios (r² = 0.22, p = 0.009), and significantly positively correlated with axial length (r² = 0.15, p = 0.03). A retinal image quality metric, calculated as two-dimensional correlation between perfect and actual retinal image, was also correlated with Landolt acuity thresholds (r² = 0.27, p = 0.003). No such correlations were found with Vernier acuity performance (r² < 0.03, p > 0.3). Based on these results, hyperacuity thresholds are, contrary to resolution acuity, not affected by higher order aberrations of the eye.

Visual performance of an extended depth of focus intraocular lens for treatment selection

PURPOSE

To evaluate the visual performance of an extended depth of focus (EDOF) intraocular lens (IOL) for patient selection.

METHODS

This prospective non-comparative case series evaluated fifty-two eyes (26 patients) after bilateral implantation of the Tecnis Symfony IOL. Exclusion criteria were previous ocular surgeries, corneal astigmatism of >1.5 diopter, and ocular pathologies or corneal abnormalities. Uncorrected (UCVA) and distance-corrected (DCVA) visual acuity (VA) in 4 m, 80 cm, 60 cm and 40 cm (logMAR), defocus curve, contrast sensitivity (CS) and a questionnaire on subjective quality of vision (QoV) were assessed after 3 months.

RESULTS

UCVA was -0.02 ± 0.071 logMAR at 4 m, 0.01 ± 0.077 logMAR at 80 cm, 0.08 ± 0.187 logMAR at 60 cm and 0.22 ± 0.153 logMAR at 40 cm. Defocus curve testing showed a flat VA range from 0.00 to -1.50 D (-0.05-0.02 logMAR). At near distance from -2.0 to -2.5 D a dip of DCVA was observed (0.14-0.28 logMAR). CS under photopic and mesopic conditions without and with glare was 1.56 logCS, 0.86 logCS, 0.78 logCS, respectively. Spectacle independence was achieved in 100% for distance and intermediate vision and 71% of patients at near distance.

CONCLUSION

This EDOF IOL provides excellent intermediate and far (<0.1 logMAR) and acceptable near UCVA (<0.3 logMAR). Defocus curve testing confirmed an EDOF between far and intermediate distance and showed a dip at near distance. It provides good QoV, CS, high spectacle independence, perception of few optical phenomena, and particularly good night-driving capabilities.

Fast Measure of Visual Acuity and Contrast Sensitivity Defocus Curves with an iPad Application

Objective:

To evaluate the repeatability of the fast measurement of the visual acuity (VADC) and contrast sensitivity (CSDC) defocus curves with a new test as well as the agreement of measurements at far distance obtained with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart and the ClinicCSF test for measuring Contrast Sensitivity Function (CSF).

Method:

Records from fifty-nine subjects implanted with Multifocal Intraocular Lenses (MIOLs) were retrieved from our database. VADC and CSDC were measured from +1.00 D to -4.00 D in 0.50 D steps. The agreement with the ETDRS and the CSF at far distance was assessed in comparison to the 0 D location of the VADC and the CSDC, respectively. The repeatability was evaluated in 34 subjects who consecutively repeated two measures.

Results:

Median Visual Acuity (VA) was -0.1 logMAR with the VADC at 0 D of defocus and 0 logMAR with the ETDRS (p>0.05). A total of 45.8% of eyes showed no differences between both tests and the difference was less than one line of VA in 96.6% of the eyes. The intrasubject repeatability was under one line of VA along all the defocus curve except for positive defocus levels. The CSDC showed the best agreement with the CSF for 18 cycles per degree. The CSDC was less repeatable than VADC. Mean time spent on completing the VADC and CSDC was 7.81 and 7.98 minutes, respectively.

Conclusion:

The VADC showed good agreement with the ETDRS and good repeatability despite the short testing time. In contrast, poorer repeatability was found for CSDC. Our method would facilitate the inclusion of VADC in clinical practice as it is a fast test, being also the first one including the measure of CSDC.

Long-Term Clinical Outcomes after Mix and Match Implantation of Two Multifocal Intraocular Lenses with Different Adds

Purpose

To compare long-term clinical outcomes between patients with bilateral implantation of +3.0 diopter (D) multifocal intraocular lenses (IOLs) and mix and match implantation of +2.5 D and +3.0 D multifocal IOLs.

Material and Methods

This retrospective observer-masked cohort study comprised 66 eyes of 33 patients with two different strategies of binocular multifocal IOLs implantation: bilateral +3.0 D (17 patients) (bilateral group) and mix and match +2.5 D and +3.0 D (16 patients) (blended group). Patients were recruited 1 year (±3 months) after second-eye surgery. The primary effectiveness endpoint was binocular uncorrected intermediate visual acuity (UCIVA) at 70 cm. The secondary assessments included binocular visual quality tests and quality-of-vision questionnaire.

Results

The blended group showed clinically better UCIVA (0.10 ± 0.07 logMAR) at 70 cm than the bilateral group (0.26 ± 0.09 logMAR) with a difference of 0.16 ± 0.08 logMAR (P < 0.001). Similar binocular visual acuities were achieved between the two groups at the near and far distance. The binocular defocus curves showed better performance in the blended group from 50 cm to 1 m. The mean binocular contrast sensitivities under the photopic conditions with or without glare and mesopic condition without glare were clinically better in the blended group. Both the groups reported low rate of visual phenomena, high rate of spectacle independence, and satisfaction.

Conclusions

Comparing with bilateral implantation of +3.0 D multifocal IOLs during the cataract surgery, mix and match implantation of +2.5 D and +3.0 D multifocal IOLs provides a wider depth of binocular focus, especially for intermediate distances, and better binocular visual quality.

Percepção Visual no Tremor Essencial: Uma Revisão Sistemática

RESUMO Investigou-se a relação entre percepção visual e tremor essencial (TE). Realizou-se uma revisão dos estudos publicados sobre o tema nas bases de dados PubMed, BIREME, CINAHL, Web of Science, PsycINFO, SciELO, SCOPUS e ELSEVIER desde a origem até 05 de janeiro de 2017. A triagem, extração de dados e avaliação foram realizadas por dois revisores. Para avaliar a qualidade dos estudos utilizou-se as diretrizes do National Institutes of Health (NIH). De 132 estudos potencialmente elegíveis, 12 foram selecionados de acordo com os critérios de elegibilidade. Os resultados indicaram que pessoas com TE apresentam baixa sensibilidade visual quando comparados com indivíduos saudáveis, apesar de não apresentarem prejuízos na visão de cores. Apesar da heterogeneidade dos dados, observamos que existem prejuízos visuais em pessoas com TE e estes podem ser uma das principais características clínicas não-motoras.

Influence of age and spectral power distribution on mesopic visual sensitivity

The ability of the human visual system to detect stimuli at low illumination levels provides awareness of potential risks. The influence of age and spectral power distribution on mesopic spectral sensitivity is analyzed. Two typical light sources are used, a high-pressure sodium lamp (HPS), with a higher content of long wavelengths, and a metal halide lamp (MH), with a higher content of short wavelengths. Two experiments were performed, using a two-channel Maxwellian-view optical system to measure contrast threshold under different experimental conditions. In Experiment 1, three age groups (young, middle-aged and old, n = 2 each), two retinal locations (on-axis and off-axis vision), four background luminances (0.01, 0.07, 0.45, and 3.2 cd/m²), and two photometry systems (photopic and the MES2 systems) were considered. In Experiment 2, contrast threshold measurement was performed with two age groups (young and old, n = 11 each), one retinal location (off-axis vision), one background luminance (0.01 cd/m²), and two photometry systems (photopic and the MES2 systems). In on-axis vision, neither age nor spectral power distribution have an effect on the contrast threshold. In off-axis vision, however, a significant interaction between age and spectral power distribution is obtained, albeit only at 0.01 cd/m² with an MH lamp. Only at this lowest background luminance was the greater content of short wavelengths of this lamp responsible for higher rod stimulation in off-axis vision, with the subsequent improvement in detection performance in young subjects. However, the effect of diffused light inside the aged eye counteracted the benefits of increased rod sensitivity for the MH lamp.

Unilateral Multifocal Intraocular Lens Implantation in a Patient with Adie's Pupil

Purpose

To report a case of a patient with unilateral Adie's pupil who underwent bilateral cataract extraction with multifocal and monofocal posterior chamber intraocular lens (IOL) implantation.

Methods

A 74-year-old woman presented to our institution complaining of worsening near vision. Gross examination revealed a 6-mm fixed pupil on the right eye (OD) and a 5-mm pupil reacting to 3 mm with light on the left eye (OS). Slit lamp examination revealed a tonic pupil with an exaggerated pupillary constriction to dilute pilocarpine OD. Dilated exam revealed 2–3+ nuclear and cortical lens changes bilaterally. The patient's active lifestyle, personality, and biometry measurements made her a good candidate for multifocal IOL (MfIOL) implantation OS. Femtosecond laser-assisted cataract extraction with a ReSTOR +3 ADD (SN60D1) implantation was performed OS. Monofocal lens implantation (SN60WF) was performed OD 6 months later.

Results

One year postoperatively, our patient had an uncorrected visual acuity (VAsc) of 20/15 for distance and J10 for near OD. Her VAsc was 20/25 +1 for distance and J1 for near OS. Visual acuity when using both eyes was 20/15 for distance and J1 for near.

Conclusion

Optimizing success for MfIOL implantation is a multifactorial process. Large pupils preoperatively are of particular concern, as this may lead to increased dysphotopsia with pupil-dependent MfIOLs. Thus, patients with unilateral mydriasis, such as Aide's pupil, may have a beneficial outcome combining multifocal-monofocal implantation after bilateral cataract extraction, especially if they are not a candidate for monovision but desire spectacle independence.

Visual Outcomes After Implantation of a Segmental Refractive Multifocal Intraocular Lens Following Cataract Surgery

PURPOSE

To evaluate visual outcomes, with particular attention to intermediate visual acuity (VA), of a segmental refractive multifocal intraocular lens (IOL) with optimized depth of focus (DoF).

DESIGN

Prospective, nonrandomized, noncomparative case series.

METHODS

Setting: Department of Ophthalmology, Goethe University, Frankfurt/Germany. Patient or Study Population: Fifty eyes (25 patients) were included. Inclusion criteria were bilateral cataract, age > 45 years, corneal astigmatism ≤ 0.75 diopter (D) postoperatively, pupil size 3-6 mm (mesopic), and center shift < 1 mm (Pentacam). Exclusion criteria were ocular surgeries, amblyopia, or potential postoperative distance-corrected VA (DCVA) > 0.3 logMAR. Intervention or Observation: Uncorrected (UCVA) and DCVA in 4 m, 80 cm, 40 cm; contrast sensitivity (CS); reading skills; defocus curve; and questionnaire on optical quality (OQ) and spectacle independence were assessed after 3 months.

MAIN OUTCOME MEASURES

UCVA and DCVA in 4 m, 80 cm, 40 cm; defocus curve.

RESULTS

UCVA was 0.05 ± 0.122 logMAR at 4 m, 0.18 ± 0.164 logMAR at 80 cm, and 0.16 ± 0.140 logMAR at 40 cm. Defocus curve testing showed, respectively, a flat monocular and binocular VA range from 0.00 to -2.00 D (-0.03 to 0.11 logMAR, -0.05 to 0.05 logMAR). Median CS under photopic and mesopic conditions without and with glare was 1.81 logCS, 1.65 logCS, 1.52 logCS, and 1.14 logCS, respectively. Reading speed at 40 cm showed a reading acuity of 0.100 logRAD with 94 words/minute.

CONCLUSION

This segmental multifocal IOL provides good VA at all distances (<0.20 logMAR), particularly providing good intermediate visual acuity and DoF. It showed good reading skills, OQ, and CS and high spectacle independence.

Comparison of two methods for measuring contrast sensitivity in anisometropic amblyopia

Purpose

This study aimed to evaluate two psychophysical contrast sensitivity testing methods in amblyopic patients.

Methods

Thirty-three adults with anisometropic amblyopia participated in this study. Psychophysical contrast sensitivity was measured for both amblyopic and fellow eyes of the participants at 1, 3, and 5 cycles per degree (cpd) spatial frequencies by Freiburg visual acuity and contrast test (FrACT) and Metrovision contrast sensitivity test, which employ sine-wave gratings for measurement of contrast sensitivity. We evaluated the correlation between the two tests and used Bland-Altman analysis to measure the agreement between the two methods.

Results

Except for 1 cpd in amblyopic eyes, FrACT showed significantly higher contrast sensitivity measurements than Metrovision at all spatial frequencies both in normal and amblyopic eyes (P < 0.01). The difference between the two methods increased with an increase in spatial frequency. There was a significant correlation between the two tests at most of the spatial frequencies. While the difference between the results of the two tests increased with an increase in contrast sensitivity in amblyopic eyes, we found an inter-test agreement in normal eyes.

Conclusion

Although both FrACT and Metrovision employ sine-wave gratings to measure contrast sensitivity, there are some differences between them, and their results can not be used interchangeably.

Visual Performance of a Quadrifocal (Trifocal) Intraocular Lens Following Removal of the Crystalline Lens

PURPOSE

To evaluate visual performance after implantation of a quadrifocal intraocular lens (IOL).

METHODS

Setting: Department of Ophthalmology, Goethe University, Frankfurt, Germany.

STUDY POPULATION

Twenty-seven patients (54 eyes) received bilateral implantation of the PanOptix IOL (AcrySof IQ PanOptixTM; Alcon Research, Fort Worth, Texas, USA) pre-enrollment. Exclusion criteria were previous ocular surgeries, corneal astigmatism of >1.5 diopter (D), ocular pathologies, or corneal abnormalities. Intervention or Observational Procedure(s): Postoperative examination at 3 months including manifest refraction; uncorrected visual acuity (UCVA) and distance-corrected visual acuity (DCVA) in 4 m, 80 cm, 60 cm, and 40 cm slit-lamp examination; defocus testing; contrast sensitivity (CS) under photopic and mesopic conditions; and a questionnaire on subjective quality of vision, optical phenomena, and spectacle independence was performed.

MAIN OUTCOME MEASURE(S)

At 3 months postoperatively, UCVA and DCVA in 4 m, 80 cm, 60 cm, and 40 cm (logMAR), defocus curves, CS, and quality-of-vision questionnaire results.

RESULTS

Mean spherical equivalent was -0.04 ± 0.321 D 3 months postoperatively. Binocular UCVA at distance, intermediate (80 cm, 60 cm), and near was 0.00 ± 0.094 logMAR, 0.09 ± 0.107 logMAR, 0.00 ± 0.111 logMAR, and 0.01 ± 0.087 logMAR, respectively. Binocular defocus curve showed peaks with best visual acuity (VA) at 0.00 D (-0.07 logMAR) and -2.00 D (-0.02 logMAR).

CONCLUSION

Visual performance of the PanOptix IOL showed good VA at all distances; particularly good intermediate VA (logMAR > 0.1), with best VA at 60 cm; and high patient satisfaction and spectacle independence 3 months postoperatively.

Visual function and retinal vessel diameters during hyperthermia in man

PURPOSE

To assess the effect of elevated core body temperature on temporal and spatial contrast sensitivity and retinal vessel diameters.

METHODS

The study included 13 healthy volunteers aged 20-37 years. Core body temperature elevation (target +1.1°C) was induced by wrapping the participants in cling film, tinfoil and warming blankets. Subsequent cooling was achieved by undressing. Flicker sensitivity (critical flicker fusion frequency) was chosen to assess temporal resolution, while the Freiburg Vision Test was used to determine spatial contrast sensitivity at 1.5 cycles per degree. Scanning laser ophthalmoscopy was used to measure retinal trunk vessel diameters. Assessment was made at baseline, during hyperthermia and after cooling.

RESULTS

The induction of a mean increase in core body temperature of 1.02°C was associated with a 7.15-mmHg mean reduction in systolic blood pressure (p < 0.01), a 10.6-mmHg mean reduction in diastolic blood pressure (p < 0.01), a mean increase in pulse rate of 36.3 bpm (p < 0.0001), a 2.66% improvement in flicker sensitivity (CI₉₅ 1.37-3.94, p < 0.001), a 2.80% increase in retinal artery diameters (CI₉₅ 1.09-4.51, p < 0.01) and a 2.95% increase in retinal vein diameters (CI₉₅ 0.96-4.94, p < 0.01). There was no detectable effect of temperature on spatial contrast sensitivity. All ocular test parameters returned to baseline levels after cooling.

CONCLUSION

Increased core body temperature was accompanied by improved temporal visual resolution and retinal trunk vessel dilation. The results suggest that hyperthermia is associated with enhanced retinal function and increased retinal metabolism.

Comparative analysis of the visual performance after implantation of the toric implantable collamer lens in stable keratoconus: a 4-year follow-up after sequential procedure (CXL+TICL implantation)

Aims

To report on 4-year postoperative visual performance with the toric implantable collamer lens (TICL) for stable keratoconus after sequential procedure (corneal collagen crosslinking plus TICL implantation).

Methods

Forty eyes of 24 patients with stable keratoconus with myopia between 0.00 and −18.00 dioptres (D) and astigmatism between 1.25 and 8.00 D were evaluated in this prospective interventional study (https://clinicaltrials.gov/ct2/show/NCT02833649). We evaluated refraction, visual outcomes, astigmatic changes analysed by Alpins vector, contrast sensitivity, aberrometry, modulation transfer functions (MTFs), defocus curve, and operative and postoperative complications.

Results

At 4-year follow-up, 45% had 20/20 vision or better and 100% had 20/40 or better uncorrected visual acuity (UCVA). Vector analysis of refractive astigmatism shows that the surgically induced astigmatism (SIA) (3.20±1.46 D) was not significantly different from the target induced astigmatism (TIA) (3.14±1.42 D) (p=0.620). At 4 years postoperatively, none of the eyes showed a decrease in UCVA, in contrast to 24 eyes in which UCVA was increased by ≥1 lines, with contrast sensitivity and improvement in total aberrations and MTF value at 5 per degree (*p=0.004) after TICL implantation. The cumulative 4-year corneal endothelial cell loss was ≤5%. No patients reported dissatisfaction. At the end of follow-up, the vault was 658±54.33m (range, 500–711) and the intraocular pressure was 11.7±2.08 mm Hg. Occurrences of glare and night-driving troubles diminished after TICL surgery.

Conclusion

The results from this standardised clinical investigation support TICL implantation from clinical and optical viewpoints in patients with stable keratoconus.

Trial registration number

NCT02833649, Pre-results

Axis-free correction of astigmatism using bifocal soft contact lenses

PURPOSE

Pilot study to investigate the feasibility of an axis-free correction approach of regular astigmatism using soft, bifocal contact lenses (CL).

METHODS

The investigation covers an optical simulation and a pilot study for the assessment of visual performance (over refraction OR, monocular visual acuity VA). The power of the two zones was adjusted according to the power of the astigmatic meridians, individually. Subjective performance was assessed in 30 participants with a mean horizontal cylindrical component of J₀=- 0.65±1.29 D (cylinder from -0.75 to -4.00 DC). OR and VA were measured directly after fitting the CL, after one hour and after 5days (3FUP).

RESULTS

Evaluating the modulation transfer function, CL increased the Strehl ratio by 10% and the transferred spatial frequency was improved from 6.6 cpd to 21.3 cpd. Analysis of Sturm's interval revealed a residual astigmatism of D_Ast=0.73 D. OR revealed a statistically significant reduction of spherical error between baseline and all follow up (ΔM=-2.14 D, p<0.001) and between the J₀ from baseline to 3FUP (ΔJ₀=-0.46 D, p=0.04). Wearing the CL for 5days did not result in a significant difference of VA (ΔVA_3FUP=+0.01 logMAR, p=0.99).

CONCLUSION

Axis-free correction of astigmatism using bifocal CL resulted in reasonable performance based on computer simulation. Participants showed no clinically reduced visual acuity or contrast sensitivity. Further clinical studies are needed to show if this approach provides a good alternative to conventional astigmatic correction.

Efficient Characterization and Classification of Contrast Sensitivity Functions in Aging

The contrast sensitivity function (CSF), delineating contrast sensitivity over a wide range of spatial frequencies, provides a comprehensive characterization of spatial vision and a sensitive test for many physiological and pathological processes. A precise CSF measurement tool for the aging population is of great theoretical and practical importance. In the current study, we tested whether the assumptions of the newly developed quick CSF method were valid and whether it can rapidly, reliably, and effectively evaluate CSFs in the aging population. The quick CSF method combines Bayesian adaptive inference with an information gain strategy to directly estimate four parameters that define the observer’s CSF. Eighteen young and twenty-five old observers participated in the evaluation of the quick CSF method. All observers were screened for ophthalmological and mental diseases. Our results showed that the CSFs derived from the quick CSF method well matched with those from the traditional Ψ method, with excellent test-retest reliability. More importantly, the quick CSF method can accurately detect the difference of CSFs between the young and old groups. Aging significantly degrades contrast sensitivity. The quick CSF method demonstrates great potentials for both laboratory research and clinical applications in the aging population.

Predicting individual contrast sensitivity functions from acuity and letter contrast sensitivity measurements

Contrast sensitivity (CS) is widely used as a measure of visual function in both basic research and clinical evaluation. There is conflicting evidence on the extent to which measuring the full contrast sensitivity function (CSF) offers more functionally relevant information than a single measurement from an optotype CS test, such as the Pelli-Robson chart. Here we examine the relationship between functional CSF parameters and other measures of visual function, and establish a framework for predicting individual CSFs with effectively a zero-parameter model that shifts a standard-shaped template CSF horizontally and vertically according to independent measurements of high contrast acuity and letter CS, respectively. This method was evaluated for three different CSF tests: a chart test (CSV-1000), a computerized sine-wave test (M&S Sine Test), and a recently developed adaptive test (quick CSF). Subjects were 43 individuals with healthy vision or impairment too mild to be considered low vision (acuity range of -0.3 to 0.34 logMAR). While each test demands a slightly different normative template, results show that individual subject CSFs can be predicted with roughly the same precision as test-retest repeatability, confirming that individuals predominantly differ in terms of peak CS and peak spatial frequency. In fact, these parameters were sufficiently related to empirical measurements of acuity and letter CS to permit accurate estimation of the entire CSF of any individual with a deterministic model (zero free parameters). These results demonstrate that in many cases, measuring the full CSF may provide little additional information beyond letter acuity and contrast sensitivity.