Evaluation of objective and subjective binocular ocular refraction with looking in type.

BACKGROUND: This study aimed to compare the results of the Chronos binocular/monocular refraction system, that measures objective and subjective ocular refraction in one unit, to objective findings obtained from a conventional autorefractometer and a conventional subjective ocular refraction using a trial-frame in real space. METHODS: Twenty-eight healthy volunteers (21.2 ± 1.5 years old) were included in this study. Objective ocular refraction was measured using two tests: the Chronos binocular/monocular refraction system under binocular conditions and a conventional autorefractometer under monocular conditions. Subjective ocular refraction was measured using three tests: Chronos binocular/monocular refraction system under binocular, monocular conditions, and trial-frame in the real space under monocular conditions. The measurement distance was set to 5.0 m for each test. All ocular refractions were converted into spherical equivalents (SEs). RESULTS: The objective SE was significantly more negative with Chronos binocular/monocular refraction system under binocular condition (- 4.08 ± 2.76 D) than with the conventional autorefractometer under monocular condition (- 3.85 ± 2.66 D) (P = 0.002). Although, the subjective SE was significantly more negative with Chronos binocular/monocular refraction system under binocular condition (- 3.55 ± 2.67 D) than with the trial-frame in the real space under monocular condition (- 3.33 ± 2.75 D) (P = 0.002), Chronos binocular/monocular refraction system under monocular condition (- 3.17 ± 2.57 D) was not significantly different from that in trial-frame in real space under monocular condition (P = 0.33). CONCLUSION: These findings suggest that the Chronos binocular/monocular refraction system, which can complete both objective and subjective ocular refraction tests in a single unit, is suitable for screening ocular refraction, although it produces slightly more myopic results. Furthermore, subjective ocular refraction testing accuracy in Chronos binocular/monocular refraction system can be equivalent to trial-frame in real-space testing by switching from binocular to monocular condition.

Effect of binocular vision during target shooting in archery.

PURPOSE: This study aimed to evaluate the difference between binocular and monocular vision and eye movements during the competition using video-oculography (VOG). METHODS: Experiment 1 included 14 participants to evaluate differences in arrow convergence. Then, seven participants in Experiment 1 were randomly selected and included in Experiment 2, which evaluated eye movements during archery using VOG. The target used an 80-cm waterproof target face and was set at a distance of 30 m. All players shot the target 36 times using their bows and arrows. Experiments 1 and 2 evaluated the distribution of arrows in each score and the number of focus points, respectively, between binocular and monocular conditions. RESULTS: The arrows, which include the area of 9 points, were significantly greater in the binocular condition (11.85 ± 5.04 shots) than in the monocular condition (9.36 ± 5.41 shots) in Experiment 1 (P = 0.047). The players focused on the target under both binocular and monocular conditions, although the players were switching off fixation between the target and shooting sight under the binocular condition in Experiment 2. CONCLUSION: These behaviors indicated that the players were trying to accurately shoot the target by exploring the distance between themselves and the target as a cue for depth perception.

Evaluation of Aniseikonia in Patients with Successfully Treated Anisometropic Amblyopia Using Spatial Aniseikonia Test.

Anisometropic amblyopia is decreased visual acuity in one eye, and treatment consists of wearing complete corrective spectacles. Aniseikonia occurs with complete correction of anisometropia using spectacles. Aniseikonia has been ignored when treating pediatric anisometropic amblyopia because of the prevailing belief that anisometropic symptoms are suppressed by adaptation. However, the conventional direct comparison method for evaluating aniseikonia significantly underestimates the degree of aniseikonia. This study investigated whether the adaptation occurs due to long-term anisometropic amblyopia treatment in patients who have had successful amblyopia treatment using a spatial aniseikonia test with high accuracy and repeatability compared with the conventional direct comparison method. The amount of aniseikonia was not significantly different between the patients with successful amblyopia treatment and individuals with anisometropia without a history of amblyopia. In both groups, the aniseikonia per 1.00 D of anisometropia and the aniseikonia per 1.00 mm of aniso-axial length were comparable. The repeatability of the amount of aniseikonia using the spatial aniseikonia test did not differ significantly between the two groups, indicating a high degree of agreement. These findings suggest that aniseikonia is not adapted to amblyopia treatment and that aniseikonia increases as the difference between spherical equivalent and axial length increases.

Evaluation of ocular biometry in the Japanese population using a multicenter approach: Prospective observational study.

This prospective observational study aimed to evaluate the ocular biometry of Japanese people through a multicenter approach. The uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively) in the log minimum angle of resolution (logMAR), subjective and objective spherical equivalent values (SE) of ocular refraction, anterior and posterior corneal curvature (ACC and PCC, respectively), anterior and posterior corneal asphericity (ACA and PCA, respectively), central corneal thickness (CCT), anterior chamber depth (ACD), and ocular axial length (AL) were measured in the eyes of 250 participants (mean age = 46.5 ± 18.0 years, range: 20-90 years) across five institutions in Japan. The mean UDVA, CDVA, subjective SE, objective SE, ACC, PCC, ACA, PCA, CCT, ACD, and AL were 0.68, -0.08, -2.42 D, -2.66 D, 7.77 mm, 6.33 mm, -0.31, -0.39, 0.55 mm, 2.92 mm, and 24.78 mm, respectively. Age-related changes and sex-based differences were noted in the visual acuity, refraction, corneal shape, ACD, and AL. Our results serve as basis for future studies aiming to develop refractive correction methods and various vision-related fields.

Analysis of smooth pursuit eye movements in a clinical context by tracking the target and eyes.

In the evaluation of smooth pursuit eye movements (SPEMs), recording the stimulus onset time is mandatory. In the laboratory, the stimulus onset time is recorded by electrical signal or programming, and video-oculography (VOG) and the visual stimulus are synchronized. Nevertheless, because the examiner must manually move the fixation target, recording the stimulus onset time is challenging in daily clinical practice. Thus, this study aimed to develop an algorithm for evaluating SPEMs while testing the nine-direction eye movements without recording the stimulus onset time using VOG and deep learning-based object detection (single-shot multibox detector), which can predict the location and types of objects in a single image. The algorithm of peak fitting-based detection correctly classified the directions of target orientation and calculated the latencies and gains within the normal range while testing the nine-direction eye movements in healthy individuals. These findings suggest that the algorithm of peak fitting-based detection has sufficient accuracy for the automatic evaluation of SPEM in clinical settings.

Comparisons of size of foveal avascular zone area among children with posterior microphthalmos, high hyperopia, and normal eyes.

PURPOSE: To determine the area of the surface foveal avascular zone (FAZ) in children with posterior microphthalmos (PM), high hyperopia, and normal eyes using optical coherence tomography (OCT) and OCT angiography (OCTA). METHODS: Thirty-six children were studied including 6 cases 12 eyes of PM (mean age 9.5 ± 5.2 years), 15 cases 30 eyes of high hyperopia (6.9 ± 1.5 years), and 15 cases 30 eyes of healthy individuals (8.7 ± 1.7 years). The B- and C-scan images in all children were recorded by OCT and OCTA with a scanning area of 3.0 × 3.0 mm centered on the fovea. All images were corrected for axial length differences, and the area of the FAZ surface and central macular thickness (CMT) was measured manually and compared. RESULTS: The area of FAZ in the PM group was 0.007 ± 0.003 mm2, which was significantly smaller than that in the high hyperopia eyes at 0.286 ± 0.108 mm2 and healthy eyes at 0.318 ± 0.129 mm2 (both P < 0.001). The CMT in the PM group was 401.58 ± 33.60 mm, which was significantly thicker than in the high hyperopia eyes at 202.93 ± 12.28 mm and the normal eyes at 204.43 ± 18.76 mm. The area of the FAZ and CMT in the hyperopia group did not differ significantly from that of the normal healthy eyes. CONCLUSION: These findings indicate that patients with PM have a hypoplastic macular region, which must be considered in any treatment of these eyes.

Refractive changes with post-rotatory nystagmus in healthy individuals.

PURPOSE: Post-rotatory nystagmus has been used to detect autism spectrum disorders in clinical settings. Although previous studies have focused on eye movements, they did not evaluate the change in ocular refraction during post-rotatory nystagmus. This study aimed to evaluate the changes in ocular refraction during post-rotatory nystagmus in healthy individuals. METHODS: A total of 34 healthy volunteers (mean age ± standard deviation, 20.9 ± 0.6 years) participated in this study. The ocular refraction during post-rotatory nystagmus was measured using MR-6000 (Tomey Inc.) on quick mode with a sampling rate of 30 Hz under noncycloplegic and cycloplegic conditions. The amplitude of post-rotatory nystagmus was calculated on the basis of the anterior eye images, while the ocular refraction measurements were simultaneously recorded. The accommodative convergence per accommodation ratio was calculated using the heterophoria method. Video oculography was performed to measure the angle of convergence during post-rotatory nystagmus. RESULTS: The changes in ocular refraction during post-rotatory nystagmus were significantly greater under the noncycloplegic condition than under the cycloplegic condition. The changes in ocular refraction during the post-rotatory nystagmus were significantly and positively correlated with the amplitude of post-rotatory nystagmus under the noncycloplegic condition. The angle of convergence during post-rotatory nystagmus was significantly higher under the noncycloplegic condition than under the cycloplegic condition. The changes in the angle of convergence were significantly and positively correlated with the predicted accommodative convergence. CONCLUSIONS: These findings suggest that the accommodation was functional during the post-rotatory nystagmus to compensate for the retinal image slip, and the accommodative convergence can help weaken the nystagmus.

Automatic Recording of the Target Location During Smooth Pursuit Eye Movement Testing Using Video-Oculography and Deep Learning-Based Object Detection.

Purpose: To accurately record the movements of a hand-held target together with the smooth pursuit eye movements (SPEMs) elicited with video-oculography (VOG) combined with deep learning-based object detection using a single-shot multibox detector (SSD). Methods: The SPEMs of 11 healthy volunteers (21.3 ± 0.9 years) were recorded using VOG. The subjects fixated on a moving target that was manually moved at a distance of 1 m by the examiner. An automatic recording system was developed using SSD to predict the type and location of objects in a single image. The 400 images that were taken of one subject using a VOG scene camera were distributed into 2 groups (300 and 100) for training and validation. The testing data included 1100 images of all subjects (100 images/subject). The method achieved 75% average precision (AP75) for the relationship between the location of the fixated target (as calculated by SSD) and the position of each eye (as recorded by VOG). Results: The AP75 for all subjects was 99.7% ± 0.6%. The horizontal and vertical target locations were significantly and positively correlated with each eye position in the horizontal and vertical directions (adjusted R2 ≥ 0.955, P < 0.001). Conclusions: The addition of SSD-driven recording of hand-held target positions with VOG allows for quantitative assessment of SPEMs following a target during an SPEM test. Translational Relevance: The combined methods of VOG and SSD can be used to detect SPEMs with greater accuracy, which can improve the outcome of clinical evaluations.

Simultaneous Measurement of Objective and Subjective Accommodation in Response to Step Stimulation.

Purpose: This study aimed to evaluate differences in objective and subjective accommodation dynamically and simultaneously. Methods: Thirty-four pre-presbyopic healthy volunteers (mean age ± SD, 41.0 ± 3.2 years) participated in this study. Initially, the reaction time for detecting a change in the target was measured at near. Dynamic accommodation was then monocularly recorded using an open-view Shack-Hartmann aberrometer and compared with the amplitude and velocity of subjective accommodation. Results: The objective amplitude of accommodation (0.97 ± 0.32 diopter [D]) was significantly greater than the subjective amplitude of accommodation (0.62 ± 0.43 D; P < 0.001). The accommodative velocity was significantly faster for the "before the accommodation" response time (0.47 ± 0.38 D/s) than the "after the accommodation" response time (0.21 ± 0.22 D/s; P = 0.007). Conclusions: The human eye under the monocular condition quickly adjusts to the focal plane to clearly archive the nearby object, and the focal plane thereafter is slowly and accurately adjusted to the visual target after visual recognition.

Effect of color information on the diagnostic performance of glaucoma in deep learning using few fundus images.

PURPOSE: The purpose of this study was to evaluate the accuracy of the convolutional neural network (CNN) model in glaucoma identification with three primary colors (red, green, blue; RGB) and split color channels using fundus photographs with a small sample size. METHODS: The dataset was prepared using color fundus photographs captured with a fundus camera (VX-10i, Kowa Co., Ltd., Tokyo, Japan). The training dataset consisted of 200 images, and the validation dataset contained 60 images. In the preprocessing stage, the color channels for the fundus images were separated into red (red model), green (green model), and blue (blue model) using OpenCV on Windows. All images were resized to squares with a size of 512 × 512 pixels for preprocessing before input into the model, and the model was fine-tuned with VGG16. RESULTS: The diagnostic performance was significantly higher in the green model [area under the curve (AUC) 0.946; 95% confidence interval (CI) 0.851-0.982] than in the RGB model (AUC 0.800; 95% CI 0.658-0.893; P = 0.006), red model (AUC 0.746; 95% CI 0.601-0.851; P = 0.002), and blue model (AUC 0.558; 95% CI 0.405-0.700; P < 0.001). CONCLUSION: The present study showed that the green digital filter is useful for structuring CNN models for automatic discrimination of glaucoma using fundus photographs with a small sample size. The present findings suggest that preprocessing, when creating the CNN model, is an important step for the identification of a large number of retinal diseases using color fundus photographs.

Objective evaluation of visual fatigue in patients with intermittent exotropia.

PURPOSE: The purpose of this study was to evaluate the degree of visual fatigue in patients with intermittent exotropia (IXT) using the binocular fusion maintenance (BFM) test. METHODS: Fourteen patients with IXT (32.1 ± 16.4 years) and 15 age-matched healthy volunteers (31.2 ± 9.3 years) participated in the study. BFM was assessed by measuring the transmittance of liquid crystals placed in front of the subject's nondominant eye at the instance when binocular fusion was broken and vergence eye movement was induced. A questionnaire on subjective symptoms was administered to the subjects before and after the visual task. The visual task consisted of a reciprocal movement between 67 and 40 cm. RESULTS: The change [post-pre] of BFM was significantly lower in the IXT group (-0.185 ± 0.187) than in the control group (-0.030 ± 0.070) (P = 0.010). The change of total subjective eye symptom score was significantly greater in the IXT group (2.28 ± 1.43) than in the control group (0.93 ± 1.27) (P = 0.018). The reduction in BFM rate with increasing total subjective eye symptom score was significantly greater in the IXT group (-0.106 ± 0.017) than in the control group (-0.030 ± 0.013) (P = 0.006). CONCLUSION: The present findings objectively showed that patients with IXT are at a greater risk of visual fatigue in comparison with healthy individuals.

Insufficient accommodation during binocular near viewing in eyes with intermittent exotropia.

PURPOSE: To investigate the changes in spherical equivalent and pupil response during near viewing in patients with intermittent exotropia (IXT) who have complaints of blurred vision or asthenopia from near viewing in daily life using a novel binocular wavefront aberrometer. STUDY DESIGN: A cross-sectional study. METHODS: Ten IXT patients and ten healthy subjects wearing full-correction lenses at far sight (5 m) were instructed to fixate on a near target at 67 cm, which was then moved to 40 cm three times. Serial changes in the spherical equivalent (SE) refractive error (SE) were measured during this task using a laboratory-made open-field binocular Hartmann-Shack wavefront aberrometer and compared between patients and healthy subjects. In the IXT patients, regression analysis was performed between ∆SE and exodeviation angles, as measured by an alternate prism and cover test. Pupil-diameter and pupil-constriction ratios were also compared between patients and healthy subjects, and the correlation of constriction ratio with ∆SE was calculated for both groups. RESULTS: Compared to healthy subjects, IXT patients demonstrated significantly lower ∆SE of convergence (mean ± SD, 0.91 ± 0.26 D vs. 1.15 ± 0.19 D; P < 0.05) and divergence (0.93 ± 0.28 D vs. 1.16 ± 0.20 D; P < 0.05). Angle of exotropia was negatively correlated with ∆SE during far-sight and near-sight convergence and divergence (P < 0.05). Pupil-constriction ratio was also reduced in patients compared to healthy subjects (6.67% ± 3.31% vs. 11.9% ± 5.96%; P<0.05). Pupil-constriction ratio was positively correlated with ∆SE during convergence in both groups (P < 0.05). CONCLUSION: Insufficient accommodation and pupil constriction during near viewing were observed in patients with IXT who had complaints of blurred vision or asthenopia from near viewing. These conditions might contribute to symptoms, such as fatigue, eye strain and impaired visual performance.

Binocular Coordination during Smartphone Reading in Esophoric Patients.

Purpose: To evaluate binocular coordination using video-oculography (VOG) during smartphone reading in patients with esophoria (EP) compared with control subjects.Patients and methods: Ten young and adult patients with EP (25.3 ± 7.3 years) and seven orthophoric or small-angle exophoric control subjects (25.7 ± 4.8 years) were examined. Eye movements were recorded during smartphone reading at 20, 30, and 50 cm using VOG. Differences in the horizontal fixation disparity at each distance between and within the groups were analyzed.Results: Horizontal esodeviation at 20 cm in the EP group (1.23° ± 2.00°) was significantly greater than that at 30 cm (-0.39° ± 0.73°; P = .027) and was significantly greater than horizontal exodeviation at 20 cm in the control group (-0.21° ± 0.17°; P < .001).Conclusion: The current findings suggest that the horizontal fixation disparities in the patients with EP deviate to eso-direction during smartphone use.

The influence of visual field position induced by a retinal prosthesis simulator on mobility.

PURPOSE: Our aim is to develop a new generation of suprachoroidal-transretinal stimulation (STS) retinal prosthesis using a dual-stimulating electrode array to enlarge the visual field. In the present study, we aimed to examine how position and size of the visual field-created by a retinal prosthesis simulator-influenced mobility. METHODS: Twelve healthy subjects wore retinal prosthesis simulators. Images captured by a web camera attached to a head-mounted display (HMD) were processed by a computer and displayed on the HMD. Three types of artificial visual fields-designed to imitate phosphenes-obtained by a single (5 × 5 electrodes; visual angle, 15°) or dual (5 × 5 electrodes ×2; visual angle, 30°) electrode array were created. Visual field (VF)1 is an inferior visual field, which corresponds to a dual-electrode array implanted in the superior hemisphere. VF2 is a superior visual field, which corresponds to a single-electrode array implanted in the inferior hemisphere. VF3 is a superior visual field, which corresponds to a dual-electrode array implanted in the inferior hemisphere. In each type of artificial visual field, a natural circular visual field (visual angle, 5°) which imitated the vision of patients with advanced retinitis pigmentosa existed at the center. Subjects were instructed to walk along a black carpet (6 m long × 2.2 m wide) without stepping on attached white circular obstacles. Each obstacle was 20 cm in diameter, and obstacles were installed at 40-cm intervals. We measured the number of footsteps on the obstacles, the time taken to complete the obstacle course, and the extent of head movement to scan the area (head-scanning). We then compared the results recorded from these 3 types of artificial visual field. RESULTS: The number of footsteps on obstacles was lowest in VF3 (One-way ANOVA; P = 0.028, Fisher's LSD; VF 1 versus 3 P = 0.039, 2 versus 3 P = 0.012). No significant difference was observed for the time to complete the obstacle course or the extent of head movement between the 3 visual fields. CONCLUSION: The superior and wide visual field (VF3) obtained by the retinal prosthesis simulator resulted in better mobility performance than the other visual fields.

IMI - Clinical Myopia Control Trials and Instrumentation Report.

The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refractive error and/or axial length), secondary (patient reported outcomes and treatment compliance), and exploratory (peripheral refraction, accommodative changes, ocular alignment, pupil size, outdoor activity/lighting levels, anterior and posterior segment imaging, and tissue biomechanics). The currently available instrumentation, which the literature has shown to best achieve the primary and secondary outcomes, was reviewed and critiqued. Issues relating to study design and patient selection were also identified. These findings and consensus from the International Myopia Institute members led to final recommendations to inform future instrumentation development and to guide clinical trial protocols.

Comparison of visual fatigue caused by head-mounted display for virtual reality and two-dimensional display using objective and subjective evaluation.

This study aimed to evaluate objective and subjective visual fatigue experienced before and after performing a visual task while using a head-mounted display for virtual reality (VR-HMD) and two-dimensional (2D) display. Binocular fusion maintenance (BFM) was measured using a binocular open-view Shack-Hartmann wavefront aberrometer equipped with liquid crystal shutters. Twelve healthy subjects performed the BFM test and completed a questionnaire regarding subjective symptoms before and after performing a visual task that induces low visually induced motion sickness (VIMS). BFM (p = .87) and total subjective eye symptom scores (p = .38) were not significantly different between both groups, although these values were significantly lower after the visual task than before the task within both groups (p < .05). These findings suggest that visual fatigue after using a VR-HMD is not significantly different from that after using a 2D display in the presence of low-VIMS VR content. Practitioner summary: Objective and subjective evaluation of visual fatigue were not significantly different with the use of a head-mounted display for virtual reality (VR-HMD) and two-dimensional display. These results should be valuable not only to engineers developing VR content but also to researchers involved in the evaluation of visual fatigue using VR-HMD. Abbreviations: VR: virtual reality; VR-HMD: head-mounted display for virtual reality; BFM: binocular fusion maintenance; BWFA: binocular open-view Shack-Hartmann wavefront aberrometer.

Binocular coordination and reading performance during smartphone reading in intermittent exotropia.

PURPOSE: This study aimed to evaluate binocular coordination using video-oculography during smartphone reading in patients with intermittent exotropia compared to individuals with normal vision. PATIENTS AND METHODS: Eleven youth and adult patients with intermittent exotropia (21.9±9.3 years) and 15 control subjects (26.6±4.3 years) were examined. Eye movements were recorded during smartphone reading at 50, 30, and 20 cm using video-oculography. The loss of binocular coordination was tentatively defined as a horizontal disparity greater than 2°. The proportion of monocular viewing was the percentage of time for which binocularity was lost during smartphone reading. The proportion of monocular viewing, the reading speed, and the correlation between proportion of monocular viewing and reading speed were analyzed. RESULTS: The proportion of monocular viewing during smartphone reading was significantly higher in the intermittent exotropia group than in the control group (P<0.001). It was significantly more frequent at 20 cm than at 50 cm in the intermittent exotropia group (P<0.05). The reading speed was significantly negatively correlated with the proportion of monocular viewing at 30 and 20 cm in the intermittent exotropia group (P<0.05). CONCLUSION: A significant increase in the proportion of monocular viewing in the intermittent exotropia group suggests that an appropriate viewing distance should be advised so that users can maintain binocular coordination when viewing a smartphone.

Visual Target Strategies in Infantile Nystagmus Patients With Horizontal Jerk Waveform.

The aim of this study was to propose a new pathophysiological hypothesis for involuntary eye oscillation in infantile nystagmus (IN): patients with IN exhibit impaired gaze fixation, horizontal smooth pursuit and optokinetic nystagmus (OKN) and use saccadic eye movements for these underlying impairments. In order to induce saccades, they make enough angle between gaze and target by precedent exponential slow eye movements. IN consists of the alternate appearance of the saccade and the slow eye movements. Unlike most previous theories, IN is therefore considered a necessary strategy allowing for better vision and not an obstacle to clear vision. In five patients with IN, eye movements were analyzed during the smooth pursuit test, saccadic eye movement test, OKN test and vestibulo-ocular reflex (VOR) test. Their gaze fixation, horizontal smooth pursuit, OKN and the last half of the slow phase of VOR were impaired. The lines obtained by connection of the end eye positions of fast phase of nystagmus coincided with the trajectories of targets. The findings indicate that patients followed the target by the fast but not the slow phase of nystagmus, which supports our hypothesis. By setting the direction of slow phase of nystagmus opposite to the direction of the OKN stimulation, enough angle can be effectively made between the gaze and target for the induction of saccade. This is the mechanism of reversed OKN response. In darkness and when eyes are closed, IN weakens because there is no visual target and neither the saccade for catching up the target or slow phase for induction of the saccade is needed.

Correction to: Light localization with low-contrast targets in a patient implanted with a suprachoroidal-transretinal stimulation retinal prosthesis.

The original publication of this paper contain an error because of an incorrect captured corresponding author.

Light localization with low-contrast targets in a patient implanted with a suprachoroidal-transretinal stimulation retinal prosthesis.

PURPOSE: To evaluate the improvement in targeted reaching movements toward targets of various contrasts in a patient implanted with a suprachoroidal-transretinal stimulation (STS) retinal prosthesis. METHODS: An STS retinal prosthesis was implanted in the right eye of a 42-year-old man with advanced Stargardt disease (visual acuity: right eye, light perception; left eye, hand motion). In localization tests during the 1-year follow-up period, the patient attempted to touch the center of a white square target (visual angle, 10°; contrast, 96, 85, or 74%) displayed at a random position on a monitor. The distance between the touched point and the center of the target (the absolute deviation) was averaged over 20 trials with the STS system on or off. RESULTS: With the left eye occluded, the absolute deviation was not consistently lower with the system on than off for high-contrast (96%) targets, but was consistently lower with the system on for low-contrast (74%) targets. With both eyes open, the absolute deviation was consistently lower with the system on than off for 85%-contrast targets. With the system on and 96%-contrast targets, we detected a shorter response time while covering the right eye, which was being implanted with the STS, compared to covering the left eye (2.41 ± 2.52 vs 8.45 ± 3.78 s, p < 0.01). CONCLUSIONS: Performance of a reaching movement improved in a patient with an STS retinal prosthesis implanted in an eye with residual natural vision. Patients with a retinal prosthesis may be able to improve their visual performance by using both artificial vision and their residual natural vision. CLINICAL TRIAL REGISTRATION: Beginning date of the trial: Feb. 20, 2014 Date of registration: Jan. 4, 2014 Trial registration number: UMIN000012754 Registration site: UMIN Clinical Trials Registry (UMIN-CTR) http://www.umin.ac.jp/ctr/index.htm.