Estimates Of Acuity Research Articles

Visual acuity of the summer flounder (Paralichthys dentatus) captures spatial information relevant to dynamic camouflage at close range.

Dynamic camouflage is the capacity to rapidly change skin color and pattern, often for the purpose of background-matching camouflage. Summer flounder (Paralichthys dentatus) are demersal fish with an exceptional capacity for dynamic camouflage, but with eyes that face away from the substrate, it is unknown if this behavior is mediated by vision. Past studies have shown that summer flounder skin can match the pattern (i.e., spatial detail) of substrate with a high degree of precision, and for that to be achieved using sight, one testable assumption is that the resolution of vision must match the degree of detail produced in color-change performance. To test this, approaches in morphology and behavior were used to estimate visual acuity, which is the capacity of the visual system to resolve static spatial detail. Using image processing techniques, we then compared the degree of spatial detail from a relevant substrate with what may be detectable by summer flounder spatial vision. The morphological and behavioral estimates of visual acuity were calculated as 3.62 cycles per degree (CPD) ± 0.8 (s.d.) and 4.06 CPD ± 0.4 (s.d.), respectively. These estimates fall within a range of acuities known among other flatfishes and appear adequate for detecting the spatial information needed for background-matching camouflage, though only at close distances. These data provide new knowledge about summer flounder visual acuity and suggest the capacity of flounder vision to support dynamic camouflage of the skin.

What do the blind feel? Psychological distress and satisfaction with life of blind persons: A community-based study.

Progressive loss of visual acuteness is known to be associated with anxiety, insecurity, loss of independence, and altered social functioning, which may lead to low mood and subsequently depression. Emotionally adjusting to vision loss can dramatically change one's independence. Reduced workplace productivity in adults with visual impairment is associated with lower rates of workforce participation and increased rates of anxiety and depression. Most studies for psychological comorbidities in the legally blind population are conducted in individuals who present to the psychiatry or psychology department/clinics or to facilities for blindness certification. Due to the paucity of community-based data in the Indian scenario, the current study was undertaken. To evaluate the psychological distress and satisfaction with life of people who were diagnosed as blind in the community. The sample was based on the identification of blind persons in a door-to-door screening for eye and vision problems in 44535 individuals conducted in 2015-16 in the middle to lower socioeconomic populations in the suburban area of Yerawada, Maharashtra. Those who were suspected of having low vision underwent a detailed clinical examination including visual acuity estimation, portable slit lamp examination, I-Kare tonometry, and fundoscopy, conducted by an ophthalmologist to assess and verify the lack of vision. Subsequently, the General Health Questionnaire-12 (GHQ-12) and Satisfaction with Life Scale (SWLS) were also applied upon revisiting the participants in 2020-2021. The majority of participants were middle-aged or elderly and no significant gender variation was noted in terms of blindness. Maximum psychological disability was seen after 6 to 15 years after the onset of blindness. More than 80% of the patients with complete blindness had some psychiatric comorbidity or distress and more than half reported that their daily activities were affected due to their diagnosis. Blind persons had significantly higher scores on the GHQ-12 and significantly lower scores on SWLS. Complete blindness was positively correlated with GHQ-12 scores and negatively correlated with SWLS scores and the age of the subject. This study demonstrates that psychological distress and low levels of satisfaction with life are common among the severely visually impaired and blind. There is a dire need to improve access to rehabilitation services and psychological support for the blind and their caregivers.

Effect of nystagmus on VEP-based objective visual acuity estimates

In order to determine the effect of nystagmus on objective visual acuity (VA) estimates, we compared subjective (VApsych) and objective (VEP, VAVEP) VA estimates in participants with nystagmus. For this purpose, 20 participants with nystagmus (NY) caused by idiopathic infantile nystagmus, albinism, achiasma or acquired nystagmus were recruited in this study. Estimates of BCVA (best corrected visual acuity) were determined psychophysically (VApsych; FrACT, Freiburg visual acuity test) and electrophysiologically (VAVEP; EP2000) according to ISCEV (International Society of Clinical Electrophysiology of Vision) guidelines. For each participant the eye with the stronger fixation instability [Nidek microperimeter (MP-1), Nidek Instruments] was included for further analysis. VApsych vs VAVEP were compared via paired t-tests and the correlation of the difference between VApsych and VAVEP (∆VA) vs the degree of fixation instability was tested with Pearson correlation (r). We found VAVEP to be better than VApsych [by 0.12 Logarithm of the Minimum Angle of Resolution (logMAR); mean ± standard error (SE) of VAVEP vs VApsych: 0.176 ± 0.06 vs. 0.299 ± 0.06, P = 0.017] and ∆VA to be correlated linearly with the degree of fixation instability (r2 = 0.21,p = 0.048). In conclusion, on average we report a small VA overestimation, around 1 line, for VAVEP compared to VApsych in NY. This overestimation depended on the magnitude of the fixation instability. As a rule of thumb, a reduction of the fixation probability in the central 4° from 100 to 50% leads on average to a VAVEP overestimation of around 0.25 logMAR, i.e. 2.5 lines.

The FreiBurger: a new optotype for P300-based acuity estimation.

Accurate objective assessment of visual acuity is crucial, particularly in cases of suspected malingering, or when the patient's inability to cooperate makes standard psychophysical acuity tests unreliable. The P300 component of the event-related potentials offers a potential solution and even allows for the use of standard optotypes like the Landolt C. However, low-vision patients with large eccentric visual field defects often struggle to locate the Landolt C gap quickly enough for a P300 to be reliably produced. Addressing this challenge, we introduce a novel optotype (the "FreiBurger") with a critical detail that extends through the optotype's center. Two experiments, with 16 and 12 participants, respectively, were conducted. In the first, psychophysical acuity estimates were obtained with both the FreiBurger and the Landolt C. In the second, we tested the performance of the FreiBurger, relative to the Landolt C, in eliciting a P300 with undegraded vision, simulated low vision, and in a simulated combination of low vision and visual field constriction. Comparable psychophysical acuity values (average difference 0.03 logMAR) were obtained for both optotypes. In the P300 recordings, both optotypes produced similar P300 responses under conditions of undegraded vision and low vision. However, with the combination of low vision and constricted visual field, the P300 could only be reliably obtained with the FreiBurger, while the amplitude was drastically reduced with the Landolt C (9.1µV vs. 2.2µV; p < 0.0005). The new optotype extends the applicability of P300-based acuity estimation to the frequently encountered combination of low vision and constricted visual field, where Landolt C optotypes fail. Although impairments were simulated in the present study, we assume that the advantages of the new optotype will also manifest in patients with such impairments. We furthermore expect the advantages to apply to time-sensitive psychophysical examinations as well.

Performance and Reliability Evaluation of an Automated Bone-Conduction Audiometry Using Machine Learning.

To date, pure-tone audiometry remains the gold standard for clinical auditory testing. However, pure-tone audiometry is time-consuming and only provides a discrete estimate of hearing acuity. Here, we aim to address these two main drawbacks by developing a machine learning (ML)-based approach for fully automated bone-conduction (BC) audiometry tests with forehead vibrator placement. Study 1 examines the occlusion effects when the headphones are positioned on both ears during BC forehead testing. Study 2 describes the ML-based approach for BC audiometry, with automated contralateral masking rules, compensation for occlusion effects and forehead-mastoid corrections. Next, the performance of ML-audiometry is examined in comparison to manual and conventional BC audiometry with mastoid placement. Finally, Study 3 examines the test-retest reliability of ML-audiometry. Our results show no significant performance difference between automated ML-audiometry and manual conventional audiometry. High test-retest reliability is achieved with the automated ML-audiometry. Together, our findings demonstrate the performance and reliability of the automated ML-based BC audiometry for both normal-hearing and hearing-impaired adult listeners with mild to severe hearing losses.

Quantifying visual acuity in Heliconius butterflies.

Heliconius butterflies are well-known for their colourful wing patterns, which advertise distastefulness to potential predators and are used during mate choice. However, the relative importance of different aspects of these signals will depend on the visual abilities of Heliconius and their predators. Previous studies have investigated colour sensitivity and neural anatomy, but visual acuity (the ability to perceive detail) has not been studied in these butterflies. Here, we provide the first estimate of visual acuity in Heliconius: from a behavioural optomotor assay, we found that mean visual acuity = 0.49 cycles-per-degree (cpd), with higher acuity in males than females. We also examined eye morphology and report more ommatidia in male eyes. Finally, we estimated how visual acuity affects Heliconius visual perception compared to a potential avian predator. Whereas the bird predator maintained high resolving power, Heliconius lost the ability to resolve detail at greater distances, though colours may remain salient. These results will inform future studies of Heliconius wing pattern evolution, as well as other aspects in these highly visual butterflies, which have emerged as an important system in studies of adaptation and speciation.

OKN-Fast: Objective visual acuity threshold measurement using the optokinetic response.

Visual acuity (VA) is the gold-standard measure for the assessment of visual function, but it is challenging to obtain in non-verbal adults and young children. We present OKN-Fast, an objective, automated method for estimation of VA using a reflexive eye movement called optokinetic nystagmus (OKN) that does not require a verbal response from the patient (VA-OKN). We tested the method in a cohort of healthy adults (n=12) with good vision, who were also blurred using a lens. On average OKN-Fast reduced the number of trials needed to determine threshold by half, as compared to a gold standard trial-by-trial assessment. The VAs determined by OKN and ETDRS were similar when blurred (no statistically significant difference). However, a significant bias of logMAR 0.2 was observed for the good vision condition. VA-OKN was highly repeatable with limits of agreement (LOA) similar to those found for ETDRS charts when blurred. However, this VA-OKN was only moderately correlated with VA measured using a ETDRS chart (r2 = 0.55). These results suggest that further optimization is warranted.Clinical Relevance- This work provides an automated approach for the estimation of visual acuity in non-verbal populations such as young children or non-verbal adults.

Discrimination of paediatric acuity test optotypes by 6-year-old children.

To compare the discrimination performance of 6-year-old children for optotypes from six paediatric visual acuity tests and to fit Luce's Biased Choice Model to the data to estimate the relative similarities and bias for each optotype. Full data sets were collected from 20 typically developing 6-year-olds who had passed a vision screening. They were presented with single optotypes labelled 6/12 at a distance of 9 m and were asked to identify the optotype using a matching task containing all optotypes from the relevant test. The data were combined to form a confusion matrix for each test and a biased choice model was fitted to the data. Median correct performance varied from 40% to 100% across optotypes, with the HOTV test having the highest values. Estimates of the similarity of each pair of optotypes indicated equal values for all pairs in the Landolt C, HOTV, Lea numbers and Tumbling E tests. The values differed for the picture tests, that is Lea Symbols and Allen figures. The estimates of bias for each individual optotype also indicated different values with the picture tests. Previous studies of the threshold acuity of young children and adults have indicated differences in acuity estimates across paediatric tests. A recognition acuity task typically requires resolving the difference information between optotypes. The performance of the 6-year-olds here reveals variance in similarity and bias values for picture tests, particularly for the Allen figures when compared with the Lea Symbols. Ideally, this analysis should be performed when designing new tests, and these results motivate progression from the use of current picture tests to well calibrated letter or number tests at the earliest possible age.

Estimation of Visual Function Using Deep Learning From Ultra-Widefield Fundus Images of Eyes With Retinitis Pigmentosa

There is no widespread effective treatment to halt the progression of retinitis pigmentosa. Consequently, adequate assessment and estimation of residual visual function are important clinically. To examine whether deep learning can accurately estimate the visual function of patients with retinitis pigmentosa by using ultra-widefield fundus images obtained on concurrent visits. Data for this multicenter, retrospective, cross-sectional study were collected between January 1, 2012, and December 31, 2018. This study included 695 consecutive patients with retinitis pigmentosa who were examined at 5 institutions. Each of the 3 types of input images-ultra-widefield pseudocolor images, ultra-widefield fundus autofluorescence images, and both ultra-widefield pseudocolor and fundus autofluorescence images-was paired with 1 of the 31 types of ensemble models constructed from 5 deep learning models (Visual Geometry Group-16, Residual Network-50, InceptionV3, DenseNet121, and EfficientNetB0). We used 848, 212, and 214 images for the training, validation, and testing data, respectively. All data from 1 institution were used for the independent testing data. Data analysis was performed from June 7, 2021, to December 5, 2022. The mean deviation on the Humphrey field analyzer, central retinal sensitivity, and best-corrected visual acuity were estimated. The image type-ensemble model combination that yielded the smallest mean absolute error was defined as the model with the best estimation accuracy. After removal of the bias of including both eyes with the generalized linear mixed model, correlations between the actual values of the testing data and the estimated values by the best accuracy model were examined by calculating standardized regression coefficients and P values. The study included 1274 eyes of 695 patients. A total of 385 patients were female (55.4%), and the mean (SD) age was 53.9 (17.2) years. Among the 3 types of images, the model using ultra-widefield fundus autofluorescence images alone provided the best estimation accuracy for mean deviation, central sensitivity, and visual acuity. Standardized regression coefficients were 0.684 (95% CI, 0.567-0.802) for the mean deviation estimation, 0.697 (95% CI, 0.590-0.804) for the central sensitivity estimation, and 0.309 (95% CI, 0.187-0.430) for the visual acuity estimation (all P < .001). Results of this study suggest that the visual function estimation in patients with retinitis pigmentosa from ultra-widefield fundus autofluorescence images using deep learning might help assess disease progression objectively. Findings also suggest that deep learning models might monitor the progression of retinitis pigmentosa efficiently during follow-up.

Quantifying visual acuity for pre-clinical testing of visual prostheses

Objective. Visual prostheses currently restore only limited vision. More research and pre-clinical work are required to improve the devices and stimulation strategies that are used to induce neural activity that results in visual perception. Evaluation of candidate strategies and devices requires an objective way to convert measured and modelled patterns of neural activity into a quantitative measure of visual acuity. Approach. This study presents an approach that compares evoked patterns of neural activation with target and reference patterns. A d-prime measure of discriminability determines whether the evoked neural activation pattern is sufficient to discriminate between the target and reference patterns and thus provides a quantified level of visual perception in the clinical Snellen and MAR scales. The magnitude of the resulting value was demonstrated using scaled standardized ‘C’ and ‘E’ optotypes. Main results. The approach was used to assess the visual acuity provided by two alternative stimulation strategies applied to simulated retinal implants with different electrode pitch configurations and differently sized spreads of neural activity. It was found that when there is substantial overlap in neural activity generated by different electrodes, an estimate of acuity based only upon electrode pitch is incorrect; our proposed method gives an accurate result in both circumstances. Significance. Quantification of visual acuity using this approach in pre-clinical development will allow for more rapid and accurate prototyping of improved devices and neural stimulation strategies.

Multi-dimensional patient acuity estimation with longitudinal EHR tokenization and flexible transformer networks.

Transformer model architectures have revolutionized the natural language processing (NLP) domain and continue to produce state-of-the-art results in text-based applications. Prior to the emergence of transformers, traditional NLP models such as recurrent and convolutional neural networks demonstrated promising utility for patient-level predictions and health forecasting from longitudinal datasets. However, to our knowledge only few studies have explored transformers for predicting clinical outcomes from electronic health record (EHR) data, and in our estimation, none have adequately derived a health-specific tokenization scheme to fully capture the heterogeneity of EHR systems. In this study, we propose a dynamic method for tokenizing both discrete and continuous patient data, and present a transformer-based classifier utilizing a joint embedding space for integrating disparate temporal patient measurements. We demonstrate the feasibility of our clinical AI framework through multi-task ICU patient acuity estimation, where we simultaneously predict six mortality and readmission outcomes. Our longitudinal EHR tokenization and transformer modeling approaches resulted in more accurate predictions compared with baseline machine learning models, which suggest opportunities for future multimodal data integrations and algorithmic support tools using clinical transformer networks.

Estimation of best corrected visual acuity based on deep neural network

In this study, we investigated a convolutional neural network (CNN)-based framework for the estimation of the best-corrected visual acuity (BCVA) from fundus images. First, we collected 53,318 fundus photographs from the Gyeongsang National University Changwon Hospital, where each fundus photograph is categorized into 11 levels by retrospective medical chart review. Then, we designed 4 BCVA estimation schemes using transfer learning with pre-trained ResNet-18 and EfficientNet-B0 models where both regression and classification-based prediction are taken into account. According to the results of the study, the predicted BCVA by CNN-based schemes is close to the actual value such that 94.37% of prediction accuracy can be achieved when 3 levels of difference can be tolerated during prediction. The mean squared error and R^2 score were measured as 0.028 and 0.654, respectively. These results indicate that the BCVA can be predicted accurately for extreme cases, i.e., the level of BCVA is close to either 0.0 or 1.0. Moreover, using the Guided Grad-CAM, we confirmed that the macula and the blood vessel surrounding the macula are mainly utilized in the prediction of BCVA, which validates the rationality of the CNN-based BCVA estimation schemes since the same area is also exploited during the retrospective medical chart review. Finally, we applied the t-distributed stochastic neighbor embedding to examine the characteristics of CNN-based BCVA estimation schemes. The developed BCVA estimation schemes can be employed to obtain the objective measurement of BVCA as well as the medical screening of people with poor access to medical care through smartphone-based fundus imaging.

Use of Endoscopy in Keratoprostheses with Biological Haptics.

In severe ocular surface disease where penetrating keratoplasty cannot be successfully performed, implantation of a keratoprosthesis can achieve visual rehabilitation. Osteo-odonto-keratoprosthesis offers good tissue integration due to its biological haptics, resulting in a better survival rate and lower extrusion rate. Due to corneal opacity, which is often complete, assessing the potential visual acuity is challenging. Also, during implantation of a keratoprosthesis or during later intraocular revision surgery, there is a limited field of view of the peripheral retina or ciliary body region. This is due to the small size and central location of the prosthesis optics and the geometric conditions of the prosthetic haptics. These factors can complicate surgery. Endoscopic video assistance was used in 7 eyes of 6different patients (6 male, 2 female, mean age 66 ± 9 years). In 3 eyes the indication was for preoperative estimation of potential visual acuity during a 23 G vitrectomy. In 2 eyes it was used during implantation surgery itself, and in 2 eyes it was used during revision surgery and vitrectomy. An endoscope with semirigid optics and an image guidance system with 3,000 pixels and 70°field of view from PolyDiagnost was used, with a 23 G trocar system. Endoscopy was successfully applied in all eyes examined. In 1 of 3 eyes where endoscopy was performed to estimate the visual acuity potential, a keratoprosthesis was subsequently planned. In the other two eyes, the visual acuity potential was rated insufficient for future keratoprosthesis surgery. Detailed assessment of the retina and optic disc was limited to gross pathologies because of low image resolution. During implantation, it was possible to visualize correct positioning of the posterior haptic behind the host cornea. Retroprosthetic membranes could successfully be removed by endoscopy-assisted vitrectomy. Endoscopy assistance offers advantages in visualization both for determining the indication for KPro surgery, during implantation, and in the management of complications after implantation of a keratoprosthesis. Low resolution of the imaging system places limits on assessment capabilities. Although technical improvements and miniaturization may enhance its future capabilities, endoscopy in its current form is already a valuable addition in the context of keratoprosthesis surgery.

Comparison of CRT and LCD monitors for objective estimation of visual acuity using the sweep VEP

PurposeTo investigate the applicability of liquid crystal displays (LCD) as suitable replacement for cathode ray tube monitors (CRT) as stimulator for the sweep VEP for estimating visual acuity.MethodsIn a first experiment, sweep VEPs were recorded in 13 healthy volunteers with best-corrected visual acuity with an LCD and a CRT monitor, respectively. Time-to-peak after stimulus and peak-to-trough amplitudes as well as the visual acuity, estimated using a second-order polynomial and the modified Ricker model, were compared between both monitor types. In a second experiment, sweep VEPs were recorded in six healthy volunteers with two levels of stimulus contrast using artificially reduced visual acuities as well as best-corrected with the same monitors as in the first experiment and additionally, a modern LCD gaming monitor with a response time of 1 ms. Time-to-peak after stimulus and peak-to-trough amplitudes were compared between the different combinations of monitors and contrasts. Finally, visual acuities estimated using the modified Ricker model were compared to subjective visual acuities determined using the Freiburg Visual Acuity and Contrast Test (FrACT).ResultsIn the first experiment, the time-to-peak after stimulus presentation was statistically significantly delayed for LCD displays (mean difference [confidence interval]: 60.0 [54.0, 65.9] ms; t(516) = 19.7096, p < 0.0001). Likewise, peak-to-trough amplitudes were statistically significantly smaller for the LCD stimulator, however, not clinically relevant (mean difference [confidence interval]: − 0.89 [– 1.59, − 0.20] µV; t(516) = − 2.5351, p = 0.0115). No statistically significant effect of the monitor type on the estimated visual acuity was found for neither method, second-order polynomial, nor the modified Ricker model. In the second experiment, statistically significant delays of the time-to-peak after stimulus onset were found for all combinations of monitor and contrast compared to the CRT monitor. A statistically significant, but not clinically relevant, difference of the peak-to-trough amplitudes was only found between the CRT monitor and the LCD gaming monitor (mean difference [confidence interval]: 2.6 [1.2, 4.0] µV; t(814) = 4.66, p < 0.0001). Visual acuities estimated from LCD stimulation significantly underestimated the subjective visual acuity up to 0.2 logMAR using the conversion formula of the first experiment. No statistically significant difference was found when using conversion formulas adjusted for each combination of monitor and contrast.ConclusionsBased on the results of this study, LCD monitors may substitute CRT monitors for presenting the stimuli for the sweep VEP to objectively estimate visual acuity. Nevertheless, it is advisable to perform a calibration and to collect normative data of healthy volunteers using best-corrected and artificially reduced visual acuity for establishing a conversion formula between sweep VEP outcome and the subjective visual acuity before replacing a CRT with an LCD stimulator.

Artificial Intelligence for the Estimation of Visual Acuity Using Multi-Source Anterior Segment Optical Coherence Tomographic Images in Senile Cataract.

PurposeTo investigate an artificial intelligence (AI) model performance using multi-source anterior segment optical coherence tomographic (OCT) images in estimating the preoperative best-corrected visual acuity (BCVA) in patients with senile cataract.DesignRetrospective, cross-instrument validation study.SubjectsA total of 2,332 anterior segment images obtained using swept-source OCT, optical biometry for intraocular lens calculation, and a femtosecond laser platform in patients with senile cataract and postoperative BCVA ≥ 0.0 logMAR were included in the training/validation dataset. A total of 1,002 images obtained using optical biometry and another femtosecond laser platform in patients who underwent cataract surgery in 2021 were used for the test dataset.MethodsAI modeling was based on an ensemble model of Inception-v4 and ResNet. The BCVA training/validation dataset was used for model training. The model performance was evaluated using the test dataset. Analysis of absolute error (AE) was performed by comparing the difference between true preoperative BCVA and estimated preoperative BCVA, as ≥0.1 logMAR (AE≥0.1) or <0.1 logMAR (AE <0.1). AE≥0.1 was classified into underestimation and overestimation groups based on the logMAR scale.Outcome MeasurementsMean absolute error (MAE), root mean square error (RMSE), mean percentage error (MPE), and correlation coefficient between true preoperative BCVA and estimated preoperative BCVA.ResultsThe test dataset MAE, RMSE, and MPE were 0.050 ± 0.130 logMAR, 0.140 ± 0.134 logMAR, and 1.3 ± 13.9%, respectively. The correlation coefficient was 0.969 (p < 0.001). The percentage of cases with AE≥0.1 was 8.4%. The incidence of postoperative BCVA > 0.1 was 21.4% in the AE≥0.1 group, of which 88.9% were in the underestimation group. The incidence of vision-impairing disease in the underestimation group was 95.7%. Preoperative corneal astigmatism and lens thickness were higher, and nucleus cataract was more severe (p < 0.001, 0.007, and 0.024, respectively) in AE≥0.1 than that in AE <0.1. The longer the axial length and the more severe the cortical/posterior subcapsular opacity, the better the estimated BCVA than the true BCVA.ConclusionsThe AI model achieved high-level visual acuity estimation in patients with senile cataract. This quantification method encompassed both visual acuity and cataract severity of OCT image, which are the main indications for cataract surgery, showing the potential to objectively evaluate cataract severity.

Comparison of visual acuity measured by ETDRS based smart phone applications I sight pro and Peek acuity versus traditional Snellen\'s chart visual acuity in children 6-14 years in a tertiary care institute in India

Covid-19 pandemic has led to children missing schools due to which eye care screening activities at schools have taken a backseat. To mitigate this home based visual acuity estimation smartphone applications are increasingly being used for the purpose of tele-ophthalmology purposes, although with no validation of the same. We aim to fulfil this lacunae. Current study was a cross sectional analysis on 286 eyes of 148 children aged between 6years to 14years attending our OPD from April 2021 to June 2021, with non-acute ocular symptomatology. Snellen’s distant visual acuity was compared against the visual acuity recorded by smart phone based Isight pro app and Peek acuity smart phone app. Statistical analysis was performed by Bland Altmann analysis by using SPSS version 21 and p&amp;#60;0.05 was taken as the level of significance. The mean differences between the smartphone-based test Isight pro and the Snellen’s chart and the smartphone-based test Peek acuity and Snellen’s acuity data were 0.06 (95%CI, 0.04–0.08) and 0.07 (95%CI,0.05–0.09) logMAR, respectively. Time taken to test visual acuity by Snellen’s chart was approximately 118.2±21.38 seconds, whereas with Isight pro and Peek acuity smart phone apps the time for testing was approximately 92±15.88 seconds and 94.03±19.73 seconds respectively. P&amp;#60;0.05.The mean visual acuity was comparable with Snellen’s chart and ETDRS based smart phone apps like Isight pro and Peek acuity. The mean time to assess visual acuity was slightly more in Snellen’s acuity than with smart phone based apps. Inability to access eye care services through screening activities in schools has been mitigated effectively by using these smart phone apps. Hence these smart phone apps can be effectively used in tele-ophthalmologic practice and screening activities in these COVID-19 pandemic times.

Evaluation of the effect of eye movements on the Sweep VEP

AbstractPurposeTo evaluate the effect of fixation stability on the sweep visual evoked potential (sVEP) visual acuity estimate in normal subjects.MethodsTwenty eyes of 10 subjects with normal ophthalmic exam and best‐corrected Snellen chart visual acuity (BCVA) of 20/20 or better in the tested eye underwent sVEP visual acuity estimation using commercially available equipment and software (Diagnosys Espion E3 System Lowell, MA, USA). sVEP was sequentially recorded under two conditions: (i) steady fixation using a central stationary target; and (ii) simulated unsteady fixation with the subject allowed roving eye movements outside the central stationary target. Fixation was monitored using eye‐tracking technology (Tobii Eye Tracker 4C, Tobii Technology AB, Sweden). Fixation stability was classified based on the proportion of fixation points within 4° retinal diameter circle (stable fixation: &gt;75% fixations within 4° circle; unstable fixation: &lt;75% fixations within 4° circle). Within‐subject differences in the estimated sVEP visual acuities under the two tested conditions were assessed using Wilcoxon non‐parametric signed comparisons with significance level set at p &lt; 0.05. Bland‐Altman plots were used to calculate 95% limits of agreement.ResultsSimulated unsteady fixation yielded significant differences in sVEP visual acuity estimation compared to steady fixation (p &lt; 0.0001). The median difference between the two conditions was 0.19 logMAR (~2 Snellen VA lines), with 95% limits of agreement ranging from 0.05 to 0.49 logMAR. Steady fixation overestimated visual acuity compared to BCVA (p &lt; 0.0001), contrary to simulated unsteady fixation, which yielded estimates not statistically different from the expected BCVA (p = 0.91).ConclusionsSimulated unsteady fixation affects sVEP acuity estimates in normal subjects. However, the estimated visual acuities are not significantly different from the expected normal visual acuity of 20/20. sVEP testing can therefore be used to document normal visual acuity without the requirement of steady and central fixation.

Prevalence of ocular morbidity in preschool children in Pune, Maharashtra

Purpose: The purpose of this study was to determine the prevalence of ocular morbidity in preschool children in Anganwadis of Pune. Methods: All preschool children from Anganwadi in the area of Vishrantwadi and Yerawada in Pune city, western India, in the age group 36 to <72 months, underwent comprehensive eye examination in October 2019–February 2020: visual acuity estimation of each eye separately, slit-lamp examination, cycloplegic refraction, orthoptic evaluation, and fundoscopy. Prior to screening, an informed written consent form was taken from their parents and class teacher. All children needing optical or medical care were provided the same. Results: We examined 1341 children (aged 3 to <6 years, mean: 3.85 ± 1.0) in 36 Anganwadis, and 693 (51.7%) were girls; 81 (6%) children were detected to have ocular morbidities. There were refractive error in 42 (3.1%), strabismus 8 (0.6%), disorder of lid and adnexa 11 (0.8%), allergic conjunctivitis 2 (0.15%), bacterial conjunctivitis 3 (0.2%), viral conjunctivitis 2 (0.15%), corneal opacity 3 (0.2%), nystagmus 4 (0.3%), convergence insufficiency 3 (0.2%), and cataract 2 (0.15%). There was no gender difference for any morbidity, but older children were more likely to have one (P < 0.001). Out of 42 having refractive error, 5/42 (12%) had myopia, 1/42 (2%) hypermetropia, 11/42 (26%) myopic astigmatism, 3/42 (7%) compound myopic astigmatism, and 22/42 (52%) had mixed astigmatism. Conclusion: Refractive error in preschool children was not an insignificant problem. Most of the morbidities were treatable, and visual impairment was preventable.

Can the Dynamic Colouration and Patterning of Bluelined Goatfish (Mullidae; Upeneichthys lineatus) Be Perceived by Conspecifics?

Bluelined goatfish (Upeneichthys lineatus) exhibit dynamic body colour changes and transform rapidly from a pale, buff/white, horizontally banded pattern to a conspicuous, vertically striped, red pattern when foraging. This red pattern is potentially an important foraging signal for communication with conspecifics, provided that U. lineatus can detect and discriminate the pattern. Using both physiological and behavioural experiments, we first examined whether U. lineatus possess visual pigments with sensitivity to long (“red”) wavelengths of light, and whether they can discriminate the colour red. Microspectrophotometric measurements of retinal photoreceptors showed that while U. lineatuslack visual pigments dedicated to the red part of the spectrum, their pigments likely confer some sensitivity in this spectral band. Behavioural colour discrimination experiments suggested that U. lineatuscan distinguish a red reward stimulus from a grey distractor stimulus of variable brightness. Furthermore, when presented with red stimuli of varying brightness they could mostly discriminate the darker and lighter reds from the grey distractor. We also obtained anatomical estimates of visual acuity, which suggest that U. lineatus can resolve the contrasting bands of conspecifics approximately 7 m away in clear waters. Finally, we measured the spectral reflectance of the red and white colouration on the goatfish body. Visual models suggest that U. lineatus can discriminate both chromatic and achromatic differences in body colouration where longer wavelength light is available. This study demonstrates that U. lineatus have the capacity for colour vision and can likely discriminate colours in the long-wavelength region of the spectrum where the red body pattern reflects light strongly. The ability to see red may therefore provide an advantage in recognising visual signals from conspecifics. This research furthers our understanding of how visual signals have co-evolved with visual abilities, and the role of visual communication in the marine environment.

Surgical Outcomes of Vitrectomy in Patients with Complications of Diabetic Retinopathy at A Tertiary Care Center

OBJECTIVE: Surgical outcomes of vitrectomy in patients with complications of diabetic retinopathy in a tertiary care center.METHODOLOGY: In this prospective, observational, interventional study, the fifty eyes underwent pars plan vitrectomy (PPV) for complications of proliferative diabetic retinopathy (PDR) from January to September 2019. The visual success for patients who underwent PPV was determined by the estimation of best-corrected visual acuity (BCVA) and central macular thickness (CMT) during the follow-up period. Statistical package for social science (SPSS) version 20 was used for data analysis. RESULTS: In this study, 86% of eyes achieved BCVA of better than 20/200. The common complication was an iatrogenic break (20%) during a surgical procedure; other complications include increase intraocular pressure (20%), hypotony (12%), and postoperative vitreous hemorrhage (14%). The use of intraoperative anti-VGGF was found to reduce intra-operative and recurrent vitreous hemorrhage with good visual outcomes.CONCLUSION: Despite medical advances in the management of patients with diabetes, mixed-gauge vitrectomy remains essential for visual rehabilitation of selected patients with non-clearing VH and tractional complications of PDR, and the use of AVEGF pre and postoperative enhance our ability to achieve the good visual outcome. KEYWORDS: Vitrectomy, Intravitreal anti-VEGF, PDR complications, 23 G, 25 G, 27 G.