Subjective Visual Acuity Research Articles

Factors Influencing Pseudo-Accommodation-The Difference between Subjectively Reported Range of Clear Focus and Objectively Measured Accommodation Range.

The key determinants of the range of clear focus in pre-presbyopes and their relative contributions to the difference between subjective range of focus and objective accommodation assessments have not been previously quantified. Fifty participants (aged 33.0 ± 6.4 years) underwent simultaneous monocular subjective (visual acuity measured with an electronic test-chart) and objective (dynamic accommodation measured with an Aston open-field aberrometer) defocus curve testing for lenses between +2.00 to −10.00 DS in +0.50 DS steps in a randomized order. Pupil diameter and ocular aberrations (converted to visual metrics normalized for pupil size) at each level of blur were measured. The difference between objective range over which the power of the crystalline lens changes and the subjective range of clear focus was quantified and the results modelled using pupil size, refractive error, tolerance to blur, and ocular aberrations. The subjective range of clear focus was principally accounted for by age (46.4%) and pupil size (19.3%). The objectively assessed accommodative range was also principally accounted for by age (27.6%) and pupil size (15.4%). Over one-quarter (26.0%) of the difference between objective accommodation and subjective range of clear focus was accounted for by age (14.0%) and spherical aberration at maximum accommodation (12.0%). There was no significant change in the objective accommodative response (F = 1.426, p = 0.229) or pupil size (F = 0.799, p = 0.554) of participants for levels of defocus above their amplitude of accommodation. Pre-presbyopes benefit from an increased subjective range of clear vision beyond their objective accommodation due in part to neural factors, resulting in a measured depth-of-focus of, on average, 1.0 D.

Evaluation of Visual Quality in Pseudophakic Eyes with Different Ocular Spherical Aberrations

ABSTRACT Purpose To evaluate the effects of different residual total ocular spherical aberration (SA) on objective and subjective visual quality in pseudophakic eyes. Methods This prospective consecutive study comprised 171 patients with age-related cataract and undergone unilateral uneventful phacoemulsification. All participants were divided into four groups based on residual ocular SA at 6 mm pupil: negative SA (≤−0.10 μm, group A), neutral SA (0.00 ± 0.05 μm, group B), slightly positive SA (0.10 ± 0.05 μm, group C), and more positive SA (0.20 μm, group D), respectively. Subjective visual acuity and contrast sensitivity, and objective optical quality and ocular aberrations were analyzed 3 months postoperatively. Results There was no significant difference in baseline measurements across all groups. Postoperatively, no statistically significant differences were found in visual acuity between groups (P > .05), while differences reached statistical significance in mesopic contrast sensitivity at 12 and 18 cpd (P < .01). There were significant differences in ocular SA and higher-order aberrations at 6 mm pupil, as well as in optical quality parameters (P < .05). Group C showed a minimum value of objective scatter index (1.17 ± 0.55) but maximum values of modulation transfer function cutoff (31.94 ± 9.18) and optical quality value OV 100% (1.07 ± 0.31), indicating lower intraocular scattering and superior optical quality. Conclusions This comprehensive evaluation is conducive to deepening the understanding of visual and optical performance of pseudophakic eye. A modest amount of positive ocular SA seemed to be a more preferable option for enhancing visual quality after aspheric ntraocular lense (IOL) implantation.

Comprehensive Evaluation of Retinal Image Quality in Comparing Different Aspheric to Spherical Intraocular Lens Implants

ABSTRACTPurpose: To compare the visual and optical quality of eyes implanted with three aspheric versus two spherical intraocular lenses (IOL) after cataract surgery.Methods: This prospective comparative study included 349 eyes of 349 patients with age-related cataract and undergone uneventful phacoemulsification. Implanted posterior monofocal IOLs have an aspheric optic (Tecnis ZCB00 [Johnson & Johnson Vision], Acrysof IQ SN60WF [Alcon], Akreos AO [Bausch & Lomb]) or a spherical optic (Akreos [Bausch & Lomb], Sensar AR40e [Johnson & Johnson Vision]). Postoperatively, objective optical quality parameters were performed using an Optical Quality Analysis System II (Visiometrics), and wave-front aberrations were assessed using a KR-1W aberrometer (Topcon). Meanwhile, subjective visual acuity was performed using a logarithm of the minimum angle of resolution chart at 3 months after cataract surgery.Results: Statistical significant differences (P < .05) across all groups were found regarding intraocular and total ocular spherical aberration (SA) at 4.0 mm and 6.0 mm pupil diameter and total high-order aberration (tHOA) at 6.0 mm pupil diameter. Furthermore, differences among the evaluated groups were observed regarding several objective parameters such as objective scatter index (OSI), modulation transfer function cutoff (MTF cutoff), Strehl ratio (SR) at two dimensions and contrast visual acuity (OV) at three contrast levels.Conclusions: The present results reflect the optical characteristics of IOL in vivo. The scattering light and high-order aberration may be the main reasons for the degradation of retinal imaging quality in comparing different aspheric to spherical IOL implants.

Objective assessment of visual acuity: a refined model for analyzing the sweep VEP.

The aim of this study was to develop a simple and reliable method for the objective assessment of visual acuity by optimizing the stimulus used in commercially available systems and by improving the methods of evaluation using a nonlinear function, the modified Ricker model. Subjective visual acuity in the normal subjects was measured with Snellen targets, best-corrected, and in some cases also uncorrected and with plus lenses (+ 1D, + 2D, + 3D). In patients, subjective visual acuity was measured best-corrected using the Freiburg Visual Acuity Test. Sweep VEP recordings to 11 spatial frequencies, with check sizes in logarithmically equidistant steps (0.6, 0.9, 1.4, 2.1, 3.3, 4.9, 7.3, 10.4, 18.2, 24.4, and 36.5cpd), were obtained from 56 healthy subjects aged between 17 and 69years (mean 42.5 ± 15.3SD years) and 20 patients with diseases of the lens (n = 6), retina (n = 8) or optic nerve (n = 6). The results were fit by a multiple linear regression (2nd-order polynomial) or a nonlinear regression (modified Ricker model) and parameters compared (limiting spatial frequency (sflimiting) and the spatial frequency of the vertex (sfvertex) of the parabola for the 2nd-order polynomial fitting, and the maximal spatial frequency (sfmax), and the spatial frequency where the amplitude is 2dB higher than the level of noise (sfthreshold) for the modified Ricker model. Recording with 11 spatial frequencies allows a more accurate determination of acuities above 1.0 logMAR. Tuning curves fitted to the results show that compared to the normal 2nd-order polynomial analysis, the modified Ricker model is able to describe closely the amplitudes of the sweep VEP in relation to the spatial frequencies of the presented checkerboards. In patients with a visual acuity better than about 0.5 (decimal), the predicted acuities based on the different parameters show a good match of the predicted visual acuities based on the models established in healthy volunteers to the subjective visual acuities. However, for lower visual acuities, both models tend to overestimate the visual acuity (up to ~ 0.4 logMAR), especially in patients suffering from AMD. Both models, the 2nd-order polynomial and the modified Ricker model performed equally well in the prediction of the visual acuity based on the amplitudes recorded using the sweep VEP. However, the modified Ricker model does not require the exclusion of data points from the fit, as necessary when fitting the 2nd-order polynomial model making it more reliable and robust against outliers, and, in addition, provides a measure for the noise of the recorded results.

Facilitating the transition from bright to dim environments

High on the list of desired capabilities for warfighters noted at the 2008 Fort Benning “Lab Day” was the development of combat protective eyewear with lenses that would instantly change the amount of light they transmit, based on incident lighting conditions. We reviewed the investigation regarding the effect of four different protective spectacle lens designs [clear, standard sunglass, step filter (SF), and electro-optical (EO)] on a soldier’s ability to rapidly transition from bright to dim environments. The dependent measures were selected to specifically permit the findings to be evaluated in both clinical and operational terms. A multifactorial analysis of variance revealed global statistically significant interactive effects regarding the viewing lenses, subject marksmanship, and subject visual acuity. The subjective preference ratings indicated a clear preference for the SF and the EO eyewear over no eyewear, the Authorized Protective Eyewear List (APEL) clear eyewear, and the APEL sun eyewear. Operational performance results while wearing either of these two optical devices (the SF eyewear and the electronic eyewear) are equally effective. Consequently, the fielding of either transition strategy provides equal acceptance and utility by the soldiers using this transitional gear.

Assessing the changes in eye optics and visual functions in patients with insulin-dependent type 2 diabetes mellitus and their relationship with blood glucose level

Purpose: To assess the changes in eye optics and visual functions depending on the level of blood sugar and glycated hemoglobin (HbA1c) in insulin-dependent type 2 diabetes mellitus (IPSD) patients with excessive body weight, who receive long-term insulin therapy.Material and methods. 32 patients (64 eyes), of which 84.4 % were women and 15.6 % men, with insulin-dependent diabetes mellitus (IPSD) but without severe general diabetic complications or concomitant eye pathology were monitored ophthalmologically for 3 years. The average duration of insulin therapy was 6 years. The average age of the patients was 60.94 ± 1.04 years; average weight, 89.1 ± 14.8 kg; average height, 163.8 ± 7.3 cm; average body mass index, 31.3 ± 4.8 kg/m2. The level of blood glucose level was determined daily with individual Accu-Check and/or OneTouch select glucometers, supplemented by scheduled monthly examinations with an endocrinologist. The level of glycated hemoglobin (HbA1c) was determined once every 3–6 months. Vision was measured by international requirements for patients with diabetes using the ETDRS (Early Treatment Diabetic Retinopathy Study Research Group) system with an ESV-3000 device. To assess lens transparency, the international Lens Opacities Classification System III (LOCS III) was used. Glycaemia level was monitored by the patients themselves with the help of individual blood glucose meters and by endocrinologists in scheduled monthly checkups. HbA1c level was measured once every 3 to 6 months.Results. Over the follow-up period, the subjective visual acuity slightly deteriorated. The anterior segment remained practically unchanged, the vitreous body showed a destruction increase, the state of the retina remained stable and conformed to that of nonproliferative diabetic retinopathy. The glucose level showed a significant drop, while the level of glycated hemoglobin HbA1c practically remained constant. The LOCS III criteria showed an increased clarity of the lens nucleus (NO), a worse transparency of cortical layers (C) deteriorated; the NC nucleus colour and P parameters of the posterior subcapsular layer practically remained the same. Conclusions. According to our data, during the development of diabetic cataracts in patients with type 2 IPSD, NO of the lens changes first followed by C changes (they become worse). With the normalization of glycemia level, diabetic retinopathy does not progress, the NO of the lens can improve, and the NC and P do not change. Normalization of glycemia is not a retarding factor for the already existing changes in C or the state of the vitreous. HbA1c is a marker and trigger for possible lens changes in patients with type 2 diabetes and prolonged insulin therapy. HbA1с is effective for tracking the dynamics of changes in the eye in these patients. The fact that the positive correlation of HbA1c and C at follow-up start changed to the negative correlation toward the end of the study indicates a disruption in lens state compensation and does not cancel the negative dynamics of state C even with a decrease in the level of HbA1c.

Assessment of subjective refraction with a clinical adaptive optics visual simulator

PurposeTo clinically validate an adaptive optics visual simulator (VAO) that measures subjective refraction and visual acuity.SettingOptics Laboratory, University of Murcia, Murcia, Spain.DesignProspective case series.MethodsUsing the adaptive optics visual simulator, 2 examiners measured the subjective refraction and visual acuity in healthy eyes of volunteers; 1 examiner also used a trial frame as a gold standard. The interexaminer reproducibility and agreement with the gold standard were estimated using the following statistical parameters: limits of agreement from Bland-Altman analysis, significance between differences (P value), and intraclass correlation coefficient (ICC).ResultsSeventy-six eyes of 38 volunteers were measured. Interexaminer reproducibility for subjective refraction was excellent (ICC ≥0.96; P > .05), with low 95% confidence interval (CI) values for the power vectors M (spherical equivalent of the given refractive error), J0 (Jackson cross-cylinder, axes at 180 degrees and 90 degrees), and J45 (Jackson cross-cylinder, axes at 45 degrees and 135 degrees) (±0.51 diopter [D], ±0.14 D, and ±0.14 D, respectively). No significant differences in subjective refraction and visual acuity were found between the visual simulator and gold standard (P > .05), with 95% CIs for M, J0, and J45 (subjective refraction) of ±0.67 D, ±0.14 D, and ±0.16 D, respectively, and a ±0.10 logarithm of the minimum angle of resolution (visual acuity).ConclusionSubjective refraction results using the adaptive optics visual simulator agreed with those of the gold standard and can be used as the baseline for visual simulation of any optical corneal profile or intraocular lens design for refractive surgery patients.

Prevalence, Risk Factors, and Impact of Myopic Macular Degeneration on Visual Impairment and Functioning Among Adults in Singapore.

To determine the prevalence, risk factors, and impact of myopic macular degeneration (MMD) on visual impairment and functioning among adults in Singapore. A comprehensive eye examination, including subjective refraction, axial length, and visual acuity (VA) measurements, was performed in adults aged ≥40 years in the Singapore Epidemiology of Eye Diseases (SEED) study. From fundus photographs, MMD was graded using the International META-PM classification. Vision-specific functioning (VSF) was assessed with a validated visual-functioning questionnaire (VF-11) using Rasch analysis. A total of 8716 phakic subjects were included in this analysis. The mean age (± SD) was 57.2 ± 9.5 years (33.5% Malays, 33.2% Indians, and 33.3% Chinese). The prevalence of myopia (spherical equivalent [SE] ≤ -0.5 diopters [D]) and high myopia (SE ≤ -5.0 D) was 35.7% and 6.0%, respectively. The age-standardized prevalence of MMD was 3.8% (95% confidence interval [CI], 3.4-4.3%). The prevalence of MMD was 7.7% among low to moderate myopes, and 28.7% among high myopes. The prevalence of MMD increased nonlinearly with SE and age. MMD was associated with older age, more myopic SE, and lower education. Subjects with Meta-PM categories 3 or 4 in the better-seeing eye had worse best-corrected VA (β, 0.19; 95%CI, 0.16-0.23) and poorer VSF (β, -9.7; 95%CI, -17.6 to -1.8) than those without MMD after multivariate adjustments. Approximately 1 in 26 phakic adults in Singapore has MMD. Older age and myopic SE are major risk factors of MMD. Severe MMD has a substantial impact on visual impairment and functioning.

Patients' satisfaction and subjective happiness after refractive surgery for myopia.

PurposeThe purpose of this study was to assess patients’ satisfaction and change in subjective happiness after laser-assisted in situ keratomileusis (LASIK).Patients and methodsThis was a retrospective cross-sectional study of 307 patients (mean age, 34.3 years; range, 20–63 years) who underwent bilateral LASIK surgery and ocular examinations, including subjective refraction and visual acuity axial length measurements at Minamiaoyama Eye Clinic. Patients also completed questionnaires on their satisfaction with the surgery, and on the subjective happiness scale (SHS) within 1 month before and 1 month after surgery. A multiple regression analysis was performed to determine the independent predictors of the SHS score.ResultsIn total, 91.2% of the patients were satisfied with surgery (very satisfied: n=155; satisfied: n=125). The SHS score increased postoperatively from 5.2±0.9 to 5.3±0.9 (P<0.001). The multiple regression analysis revealed that the preoperative SHS score (β=0.77; P<0.001) and satisfaction with surgery (β=−0.11; P=0.05) were predictors of postoperative SHS score.ConclusionLASIK may contribute to increased patient happiness.

Validation of Peek Acuity application in pediatric screening programs in Paraguay.

To validate the Peek Acuity mobile phone application in pediatric populations and compare its utility, both economic and diagnostic, against conventional screening methods using a pediatric ophthalmologist examination as the gold standard. A cohort of 393 subjects from Fernando de la Mora, Paraguay (ages 6-16y) were enrolled in the study. Subjects were randomly assigned a starting screening modality among: Peek Acuity, a single line of tumbling E optotypes set at 20/40, and Spot Vision Screener. Once completing the first screening modality, the subjects completed the two remaining techniques. Referral criteria were established based on the most current American Association of Pediatric Ophthalmology and Strabismus (AAPOS) recommendations: 20/40 for Peek Acuity and the tumbling E, and refractive error detection for the Spot Vision Screener. Subjects that failed to achieve the cut-off for any of the three screening techniques or subjects that passed the screening but were randomly selected to perform a comprehensive eye exam to determine the false negative rate, were evaluated by a pediatric ophthalmologist. This evaluation was considered the gold standard, and included vision assessment by a Snellen chart, strabismus evaluation, and cycloplegic refraction with dilated fundoscopy. We obtained 48% sensitivity, 83% specificity, 43% positive predictive value, and 86% negative predictive value for Peek Acuity's ability to refer compared to evaluation by a pediatric ophthalmologist, failing to achieve a desired sensitivity for implementation. Peek Acuity trended to overestimate the subject's visual acuity, providing a higher visual acuity that would not indicate referral for a comprehensive eye examination. However, its high specificity accurately predicted a significant number of children who did not need further evaluation. When comparing the three screening methods, no single screening modality outperformed the others. Peek Acuity represented a technology that was economically feasible compared to other screening modalities in low income settings, due to the prevalence of cell phone use. Peek Acuity represents an efficient tool that has potential for implementation in school screenings with different strategies aimed at pediatric populations due to its low cost and high specificity. An increase in sensitivity would improve detection of children with refractive errors.

The optokinetic response is effective to assess objective visual acuity in patients with cataract and age-related macular degeneration.

To estimate objective visual acuity in subjects suffering from cataract and age-related macular degeneration via the optokinetic response evoked by a non-conventional induction method (oktotype); in addition, to compare such objective outcome with the subjective acuity based on the ETDRS charts. Patients were presented with 13 sequences of symbols arranged horizontally to form a serial pattern, moving from left to right at a constant rate. In each sequence, the size of the stimuli was reduced progressively, while the operator checked for the disappearance of the optokinetic response via a small video camera mounted on the test lens frame. The minimum angular size of the serial pattern able to evoke the optokinetic response (MAER) was referred to as the objective visual acuity of the subject. Correlation between logMAER and logMAR was significant in the cataract and macular degeneration group ([Formula: see text] = 0.70, p < .0001; [Formula: see text] = 0.63, p < .0007). In the two samples, the correspondence between subjective and objective visual acuity (as, respectively, decimal units and arbitrary decimal units) was satisfactory (concordance correlation coefficient: cataract group = 0.91 and AMD group = 0.93). Test-retest reliability of the oktotype was good for the cataract group and moderate for the AMD sample (Κ 0.81 and 0.59, respectively). The oktotype seems a promising tool to objectively assess visual acuity in noncooperating subjects with cataract or macular degeneration. Further research on other clinical conditions is needed to clarify the suitability of the procedure in the clinical setting.

Primary Assessment of the Patient With Orbital Fractures Should Include Pupillary Response and Visual Acuity Changes to Detect Occult Major Ocular Injuries

Sight-threatening injuries associated with orbital fractures are of major concern to maxillofacial surgeons whom are often the first asked to assess these patients. Eliciting signs and symptoms that are predictive of these injuries would allow expedited ophthalmic consultation and appropriate management. We hypothesized that abnormal pupillary response is predictive of major ocular injuries. A retrospective cohort study of patients with facial fractures was instituted with review of all associated ophthalmic injuries. The primary predictor variables were the presence or absence of post-traumatic ocular symptoms and signs (visual acuity change, diplopia, flashes and floaters, pain on globe movement, abnormal pupillary response, restriction of eye movement, and visual field defects). Secondary predictors were pattern of fracture and mechanism of fracture. The primary outcome variable was the presence or absence of major ocular injury assessed during formal ophthalmology consultation. Descriptive statistics were calculated as categorical values. Correlation between the presence or absence of predictors and outcome (major ocular injury) was calculated using χ2 analysis, with the significance value set at P≤.01. The study included 75 patients (25% of whom were female patients) with a mean age of 41±22years. We recorded 165 minor ocular injuries and 43 major ocular injuries. The mechanisms of injury included assault (48%, n=36), motor vehicle accident (21%, n=16), fall (17%, n=13), sport (11%, n=8), and occupational (3%, n=2). The fracture pattern included zygomaticomaxillary (36%, n=27), isolated orbital floor (25%, n=19), complex (20%, n=15), and isolated orbital nonfloor (19%, n=14). Of the primary outcome predictors, only abnormal pupillary response (odds ratio, 36; P<.001) and subjective visual acuity changes (odds ratio, 10; P<.001) were predictive of major ocular injury. The mechanism of injury and pattern of fracture were not predictive of major ocular injury. During primary assessment of the patient with orbital fractures, abnormal pupillary response and subjective visual acuity changes are key predictors of occult major ocular injury.

First Results of a New Hyperaspheric Add-on Intraocular Lens Approach Implanted in Pseudophakic Patients with Age-Related Macular Degeneration

To determine the visual outcomes of the EyeMax Mono intraocular lens (IOL) technology (London Eye Hospital Pharma, London, UK), which is a foldable and injectable hydrophobic acrylic IOL implanted as an add-on solution in pseudophakic eyes with age-related macular degeneration, in a pilot study. A prospective, interventional case series. A total of 22 pseudophakic eyes (11 patients) with bilateral severe or intermediate dry age-related macular degeneration (AMD) (13 eyes) or stable wet AMD or disciform scarring (9 eyes) meeting the criteria for sulcal IOL implantation. Both eyes of participating subjects underwent small-incision ciliary sulcal implantation of a hyperaspheric, soft hydrophobic acrylic intraocular lens designed to improve the quality of the retinal image in all areas of the macula ≤10° from fixation and to generate a moderate hypermetropic correction for magnification. The primary outcome was safety as determined by intra- and postoperative complications, raised intraocular pressure requiring medical or surgical intervention, postoperative diplopia, reduction in visual field, and loss of ≥2 lines of visual acuity. Secondary outcomes were improvements in subjective and objective visual acuity (logarithm of the minimum angle of resolution). No intraoperative complication occurred. Elevated intraocular pressure values were measured directly after the operative procedure in 2 eyes (25 mmHg and 27 mmHg) and at the 1-week postoperative visit in 1 eye (22 mmHg) but not later. The mean postoperative spherical equivalent of refraction changed to+2.5 diopters, and all eyes had gained ≥2 lines of visual improvement (corrected distance visual acuity) by 6 months after surgery. Corrected near visual acuity as well as corrected distance visual acuity improved over time, suggesting a neuroadaptive component to improved visual function with the device. Devices were implanted bilaterally in all patients, and there were no reported symptoms of dysphotopsia or diplopia. Safety concerns were not identified in the short-term or medium term. These results indicate the potential of the EyeMax Mono IOL to improve near and distance visual acuity in pseudophakic eyes with intermediate to severe AMD.

Reduced vision in highly myopic eyes without ocular pathology: the ZOC‐BHVI high myopia study

BackgroundThe aim was to investigate the relationship of the magnitude of myopia with visual acuity in highly myopic eyes without ocular pathology.MethodsTwelve hundred and ninety‐two highly myopic eyes (up to −6.00 DS both eyes, no astigmatic cut‐off) with no ocular pathology from the ZOC-BHVI high myopia study in China, had cycloplegic refraction, followed by subjective refraction and visual acuities and axial length measurement. Two logistic regression models were undertaken to test the association of age, gender, refractive error, axial length and parental myopia with reduced vision.ResultsMean group age was 19.0 ± 8.6 years; subjective spherical equivalent refractive error was −9.03 ± 2.73 D; objective spherical equivalent refractive error was −8.90 ± 2.60 D and axial length was 27.0 ± 1.3 mm. Using visual acuity, 82.4 per cent had normal vision, 16.0 per cent had mildly reduced vision, 1.2 per cent had moderately reduced vision, 0.3 per cent had severely reduced vision and no subjects were blind. The percentage with reduced vision increased with spherical equivalent to 74.5 per cent from −15.00 to −39.99 D, axial length to 67.7 per cent of eyes from 30.01 to 32.00 mm and age to 22.9 per cent of those 41 years and over. Spherical equivalent and axial length were significantly associated with reduced vision (p < 0.0001). Age and parental myopia were not significantly associated with reduced vision. Gender was significant for one model (p = 0.04).ConclusionMildly reduced vision is common in high myopia without ocular pathology and is strongly correlated with greater magnitudes of refractive error and axial length. Better understanding is required to minimise reduced vision in high myopes.

Impact of Vision Therapy on Eye-hand Coordination Skills in Students with Visual Impairment.

Purpose:To evaluate the enhancing effects of vision therapy on eye–hand coordination skills in students with visual impairments.Methods:Thirty-five visually impaired patients who underwent vision therapy comprised the treatment group, and 35 patients with impaired vision who received no treatment comprised the control group. Full ophthalmic examinations were performed, including biomicroscopy, retinoscopy, and assessments of subjective refraction and visual acuity. Eye–hand coordination was evaluated using the Frostig test. Vision therapy in the treatment group was performed using the Bernell–Marsden ball, perceptual-motor pen, random blink test, and random shape assessment.Results:Data were analyzed for the 35 visually impaired patients and 35 control participants. The mean age was 11.51 ± 3.5 and 11.09 ± 3.1 years in the treatment and control groups, respectively. Female participants comprised 80% of the treatment group and 57% of the control group. Before treatment, the mean scores on the Frostig test were 22.74 ± 4.32 and 21.60 ± 4.10 in the treatment and control groups, respectively, and after treatment, the mean Frostig test scores were 24.69 ± 3.99 and 21.89 ± 3.92, respectively. Statistically significant intergroup differences were found in eye–hand coordination (P < 0.05). No significant intergroup differences were noted in the distance and near visual acuity values.Conclusion:The results demonstrated that vision therapy could significantly improve eye–hand coordination, but no enhancement was found in near or distance visual acuity.

A novel and cheap method to correlate subjective and objective visual acuity by using the optokinetic response.

To describe a novel optokinetic visual acuity estimator (Oktotype) and to report the preliminary results obtained in poorly and non-collaborative subjects. Eleven series of symbols arranged horizontally and moving from left to right at a constant rate were displayed. In each sequence, the size of the stimuli was reduced logarithmically. By using this paradigm, the objective visual acuity was computed in 26 normal subjects as the minimum size of the symbols able to evoke the optokinetic response. In the preliminary phase, three contrast levels were tested, with white noise added to the first five sequences so as to normalize the overestimate found at the lower-half range of the acuity scale. Subsequently, the correspondence between subjective and objective visual acuity was compared in 10 poorly collaborative subjects, and the agreement between optokinetic and Teller visual acuity was measured in six non-collaborative subjects. The best agreement is provided by the minimum contrast level (20%) (R 2=0.74). The correspondence between the two techniques is satisfying both in the normal and in the poorly collaborative sample (concordance correlation coefficient: 0.85 and 0.83, respectively). In the non-collaborative group, the concordance correlation coefficient between Teller acuity and OKVA ranged between 0.79 (test) and 0.85 (retest). Test-retest reliability was very good for the Oktotype (K: 0.82), and better than the Teller test (K=0.71), even if it was lower compared to Snellen acuity (K=0.95). The Oktotype seems promising to predict Snellen visual acuity in normal and poorly collaborative subjects.

Reading speed during a mesopic visual acuity task

Corrected myopes demonstrate reduced visual acuity and less stable fixational eye movements under mesopic conditions, compared to subjects without refractive error (Coletta et al., ARVO, 2007; Coletta et al., ARVO, 2016; FVM, 2016). Reduced acuity in myopia may be related to fixation instability, perhaps analogous to amblyopia, where less stable eye movements are associated with reductions in acuity and reading speed (Kanonidou et al., IOVS, 2010). In this study, we examined whether a subject's acuity and fixation stability were related to the time they spent to read an acuity line. Measurements were made on 31 subjects, mean age 25.7 years. Spherical equivalent refractions ranged from +2.25 to -10.88 D. Mesopic (0.28 cd/m2) and photopic (325 cd/m2) acuity was measured with high contrast letters, five per line, while eye position was recorded at 500 Hz using an EyeLink 1000 video-based eye tracker. Fixations were analyzed for letter sizes corresponding to the mesopic and photopic acuity limits. Fixation stability is reported as the bivariate contour ellipse area (BCEA), taken over a 2-sec interval, representing the area of fixation for 68% of the time. At the mesopic condition, subjects who took longer to read a line at their acuity limit had higher mesopic acuity (p=0.001) and smaller loss of acuity relative to their photopic acuity (p=0.025). However, there was no correlation between reading duration at the photopic acuity limit and photopic acuity (p>0.05), nor between reading duration and refractive error (p>0.05). When the mesopic acuity letter size was read at the photopic light level, BCEA decreased with increasing reading duration (p=0.032). For an acuity task in dim light, reading speed was correlated with acuity, but in an opposite direction to that reported for amblyopia; slower reading speed was associated instead with increased visual performance. Reading speed was not associated with refractive error. Meeting abstract presented at VSS 2017

Contrast Sensitivity in Microtropic and Anisometropic Eyes of Successfully Treated Amblyopes.

Objectives:To assess and compare contrast sensitivity function in the previously amblyopic and non-amblyopic “normal” eyes of patients with microtropia and anisometropia who achieved 20/20 visual acuity after occlusion therapy.Materials and Methods:Contrast sensitivity was tested monocularly on both eyes of 34 successfully treated microtropic and 15 anisometropic subjects (visual acuity 20/20 in both eyes). Contrast sensitivity function was evaluated by CSV-1000E and age-matched nomograms were used (spatial frequencies of 3, 6, 12, and 18 cycles per degree [cpd]) for comparison.Results:The mean age of subjects was 11.2±1.3 years in the microtropic group, 9.8±1.7 years in the anisometropic group (7-12 years); the mean follow-up time was 16.4±3.2 months (12 to 92) in the microtropic group and 27.7±1.8 months (12-84) in the anisometropic group. Statistical comparison of the microtropic amblyopic eyes versus non-microtropic eyes showed significant differences at spatial frequencies of 3, 12 and 18 cpd (3 cpd, t=2.8, p=0.007; 6 cpd, t=1.1 p=0.261; 12 cpd, t=2.2, p=0.033; 18 cpd, t=2.2, p=0.030). When anisometropic eyes were compared with non-anisometropic eyes, there was a significant difference only at 12 cpd (t=2.1 p=0.049). The comparison of non-amblyopic eyes versus age-matched nomograms revealed no differences at any of the spatial frequencies (p>0.05 for all).Conclusion:Contrast sensitivity was decreased in patients with amblyopia, especially in the microtropic group. The assessment of contrast sensitivity function may serve as a new parameter for termination of occlusion therapy.

Visual performance with accommodating and multifocal intraocular lenses.

To compare the visual functional outcomes with accommodating and multifocal intraocular lenses (IOLs). Our retrospective comparative study included 51 patients (60 eyes) received implantation of an accommodating IOL (Tetraflex; 16 patients, 20 eyes), a refractive multifocal IOL (ReZoom; 18 patients, 20 eyes), or a diffractive multifocal IOL (ZMA00; 17 patients, 20 eyes). Subjective refraction, visual acuity, contrast sensitivity (CS), intraocular aberration, and subjective photic phenomena were detected at 3mo after surgery. The spherical equivalent in the three groups was -0.38±0.54 D, 0.14±0.56 D, and 0.35±0.41 D, respectively. No statistically significant differences were found in uncorrected and corrected distance visual acuity and uncorrected intermediate visual acuity among the groups (P=0.39). The ReZoom group had significantly better distance-corrected intermediate visual acuity than the ZMA00 group (P=0.003). The ZMA00 group had significantly better near visual acuity than the other groups (P<0.05). Better contrast sensitivity values were observed in the Tetraflex group under most of the spatial frequencies conditions (P=0.025). The total aberration was lowest in the ZMA00 group (P=0.000), and the spherical aberration was highest in the Tetraflex group (P=0.000). The three groups had similar frequency of ghosting and glare, and the Tetraflex group had a low rate of halos (P=0.01). Both accommodating and multifocal IOLs can successfully restore distance and uncorrected intermediate visual acuities. Tetraflex accommodating IOLs perform better in CS and with less halos of photic phenomena. ReZoom refractive multifocal IOLs have better performance in distance-corrected intermediate visual acuity than ZMA00 diffractive multifocal IOLs, and the latter achieved better near visual acuity and efficiently decreased the optical aberration.

Flash Visual Evoked Potential versus Pattern Visual Evoked Potential in the Diagnosis of Strabismic Amblyopia

We included 60 children with unilateral amblyopia, their age ranging between 4 and 10 years. Thirty age and sex matched healthy children were included as a control group. The included children underwent complete ophthalmologic evaluation with focus on subjective monocular visual acuity, cycloplegic refractions, slit-lamp examination, fundus examination, orthoptic evaluation, stereoacuity, worth 4-dot test, FVEP & PVEP. All participants had stable fixation.