Measurement of paracentral stereopsis using a new method with the binocular open perimeter imovifa® in normal adults.

PURPOSE: No method to quantitatively evaluate stereopsis within the 15º visual field has been clinically established. We developed a program to measure paracentral stereopsis and evaluated its feasibility in visually normal participants. STUDY DESIGN: Experimental investigation METHODS: Ten visually normal volunteers with stereopsis of 60 arcseconds or better were included. The Stereo Eccentricity Analysis (SEA) program for stereopsis measurement across the visual field was integrated into the binocular visual field analyzer imovifa®. Subjects with established binocular stereopsis detected a stereoscopic circular target presented with crossed disparity on random dots at the fovea, 3°, 5°, 10°, and 15° on the 45°, 135°, 225°, and 315° meridians. The subjects performed two tasks for measurement in the periphery: a detection task by pressing the response button when the circular target was perceived and a localization task by tilting a joystick to indicate in which quadrant the circular target was perceived. The duration of the target presentation was 500 ms. RESULTS: The stereo thresholds at 0º and 3° did not significantly differ. The thresholds at 10º and 15º were significantly higher than at 0° (P < 0.01). While no inter-individual threshold difference was observed at the fovea, the difference was large at 15°. The stereo thresholds for the detection and localization tasks also did not differ significantly. CONCLUSION: With the SEA program, paracentral stereopsis can be measured and the stereo threshold increases with eccentricity. The SEA program appears to be a feasible clinical method to evaluate paracentral stereopsis.

Factors affecting the total occlusion time in eyes with hyperopic anisometropic amblyopia.

BACKGROUND: Amblyopia treatment by occluding the healthy eye is known to be effective during a sensitive critical period. This study aims to clarify the factors for the total occlusion time (TOT) required for the amblyopic eye to achieve a normal visual acuity (VA) level of 1.0 (0.0 logMAR equivalent). This could contribute to an efficient treatment plan for eyes with hyperopic anisometropic amblyopia. METHODS: Subjects were 58 patients (26 boys and 32 girls; age range, 3.6-9.2, average, 5.8 ± 1.3 years) with hyperopic anisometropic amblyopia. All the subjects had initially visited and completed occlusion therapy with improved VA of 1.0 or better in the amblyopic eye at Kindai University Hospital between January 2007 and March 2017. Using the subjects' medical records, we retrospectively investigated five factors for the TOT: the age at treatment, the initial VA of the amblyopic eye, refraction of the amblyopic eye, anisometropic disparity, and the presence of microstrabismus. Patient's VA improvement at one month after treatment was also evaluated to confirm the effect of the occlusion therapy. RESULTS: The initial VA of the amblyopic eye ranged from 0.1 to 0.9 (median, 0.4). The TOT ranged from 140 to 1795 (median, 598) hours with an average daily occlusion time of 7 hours. The initial VA of the amblyopic eye and presence of microstrabismus were the significant factors for the TOT (p < 0.01). To achieve VA of 1.0 or better, patients with an initial VA of ≤ 0.3 in the amblyopic eye required a longer TOT. Moreover, patients with concomitant microstrabismus required a 1.7-fold longer TOT compared to those without microstrabismus. CONCLUSION: Longer daily occlusion hours and early start of the treatment will be necessary for patients with poor initial VA or microstrabismus to complete occlusion therapy within the sensitive critical period.

The Association Between Improvement of Stereoacuity and Suppression in the Treatment of Anisometropic Amblyopia.

Purpose: To investigate the association between stereoacuity and suppression during occlusion therapy for patients with anisometropic amblyopia. Design: Retrospective study. Patients and Methods: This study included 19 patients with hyperopic anisometropic amblyopia who underwent occlusion therapy. The mean age of the patients was 5.5 ± 1.4 years. The participants were evaluated for improvement in stereoacuity and suppression before beginning occlusion therapy, when the highest amblyopic visual acuity (VA) was achieved, during tapering, at the end of occlusion therapy, and at the final visit. Stereoacuity was evaluated using the TNO test or JACO stereo test. The presence of suppression was evaluated using circle No. 1 of the Stereo Fly Test or JACO results as the optotype. Results: Of the 19 patients, 13 (68.4%) had suppression before occlusion, eight (42.1%) when the highest VA was achieved, five (26.3%) during tapering, and none at the final visit. Of the 13 patients with suppression before occlusion, 10 (76.9%) showed further improvement in stereoacuity when suppression disappeared, and nine had foveal stereopsis of 60 arcseconds. A significant association was confirmed between foveal stereopsis and suppression when the highest VA was achieved and during the tapering period (P<0.05, Fisher's exact test). Conclusion: Suppression was observed even when the VA in amblyopic eyes reached the highest score. By gradually decreasing the duration of occlusion, suppression was eliminated, leading to the acquisition of foveal stereopsis.

National survey of amblyopia treatment in Japan: comparison with amblyopia treatment study results of the pediatric eye disease investigator group.

PURPOSE: To investigate the treatment policy for amblyopia in Japan as of 2017 through a survey of multiple facilities and to compare the findings with those obtained by the Amblyopia Treatment Study (ATS) of the Pediatric Eye Disease Investigator Group. STUDY DESIGN: Questionnaire survey study. SUBJECTS AND METHODS: A questionnaire was sent to 181 facilities where patients with amblyopia are being treated. The outcomes of the present survey were compared with the results of the ATS study, and the coincidence rates were evaluated. RESULTS: The questionnaire response rate was 68.0%. The treatment plan that showed the highest agreement between the outcomes of the ATS study and the present study was whether or not treatment was to be given to patients aged 10-15 years who had received no previous treatment; 90% of the facilities answered that they would provide treatment to such patients as well. The next highest agreement was the future treatment of amblyopia with stable visual acuity in the affected eye; 82.6% of the facilities responded that they would reduce the occlusion time. On the other hand, the lowest agreement rate was the follow-up period of the refractive correction for moderate anisometropic amblyopia. The ATS showed "4 months," whereas most of the facilities in the present survey replied "3 months." The agreement rate was 10.8%. CONCLUSION: The amblyopia treatment in Japan survey did not always agree with the research results of the ATS. Japanese ophthalmologists tend to make treatment plans for amblyopia according to their clinical experience.

Effects of orthoptic training for residual diplopia after surgical repair of blowout fractures.

PURPOSE: To investigate the effects of orthoptic training for residual diplopia after blowout fracture (BOF) surgery. METHODS: We retrospectively reviewed the medical records of 14 (average age, 22.9 ± 13.1 years) patients with residual diplopia, who had undergone orthoptic training after BOF surgery at the Department of Ophthalmology, Kindai University Hospital, between August 2013 and September 2019. The orthoptic training included exercises for eye movement, convergence, and fusional area expansion. We assessed the training effects by scoring patients' Hess screen (Hess) test results and fields of binocular single vision (BSV). The scores obtained before/after surgery and after training were compared. We also investigated the factors that influenced patients' BSV scores after training. p < 0.05 was considered statistically significant. RESULTS: The respective pre- and postoperative and after-training average scores were 7.0 ± 5.3, 5.4 ± 4.3, and 2.5 ± 3.2 points for Hess and 50.0 ± 41.3, 48.2 ± 35.9, and 89.4 ± 14.0 points for BSV. Neither Hess nor BSV score showed a significant difference before and after surgery (p > 0.05, the Steel-Dwass test). Compared to the postoperative (i.e., before training) scores, both Hess and BSV scores significantly improved after training (p < 0.05 for Hess, p < 0.01 for BSV; the Steel-Dwass test). CONCLUSION: Orthoptic training appeared effective in resolving residual diplopia after BOF surgery by improving patients' ocular motility and expanding the BSV field.

Efficacies of preoperative prism adaptation test and monocular occlusion for detecting the maximum angle of deviation in intermittent exotropia.

BACKGROUND: The efficacies of prism adaptation test (PAT) and monocular occlusion (MO) and their optimal test durations to detect the maximum angles of deviation at near and distance in eyes with intermittent exotropia (IXT) were assessed and compared. METHODS: We retrospectively reviewed the medical records of 72 patients with IXT. All the patients had undergone the initial strabismus surgery between April 2015 and October 2018 and had been preoperatively tested by both PAT and MO performed on different days for 30 and 60 min. Near and distance deviations after 30 and 60 min of PAT and MO were compared to their baseline measurements obtained immediately after prism wear and before occlusion by alternate prism cover test. The near/distance measurements and required test duration to reveal the maximum deviation angle were also compared between PAT and MO. RESULTS: Compared with the baseline, the near deviation by PAT significantly increased after 30 (P < 0.05) and 60 (P < 0.01) minutes but not the distance deviation. However, the increase after 30 min was not significant. By MO, neither near nor distance deviation showed a significant difference from the baseline after 30 and 60 min. PAT showed a significantly larger near deviation than MO at 30 and 60 min, but a larger distance deviation by PAT was only observed at 30 min. CONCLUSIONS: In patients with basic and convergence insufficiency types of IXT, a 30-minute PAT appears to be more effective than MO in revealing the maximum angle of deviation before strabismus surgery.

Effect of Sensitivity Disparity Between the Two Eyes on Pointwise Monocular Sensitivity Under Binocular Viewing in Patients With Glaucoma.

PRCIS: A difference between monocular sensitivities measured with and without occlusion was observed in glaucoma. Monocular sensitivity without occlusion could have been affected differently by binocular interaction due to the sensitivity disparity between both eyes. PURPOSE: To investigate the influence of sensitivity disparity between both eyes on visual field results under binocular viewing in glaucoma. MATERIALS AND METHODS: Thirteen glaucoma patients tested by Humphrey Field Analyzer (HFA) and imo were reviewed retrospectively. On the basis of their HFA results, we defined the eye with a better HFA-MD as "the better eye" and the fellow eye with a worse HFA-MD as "the worse eye." Depending on the pointwise pattern deviation (PD) of both eyes, all evaluated test points were classified into 4 groups: normal PD in both eyes (N/N), normal PD in the better eye but abnormal in the worse eye (N/A), abnormal PD in the better eye but normal in the worse eye (A/N), and abnormal PD in both eyes (A/A). Using imo, which can measure sensitivity with and without occluding the nontested eye, the better eye's sensitivities with and without occlusion were compared in each group using weighted data. The weight was derived by applying the inverse probability weighting. RESULTS: Monocular sensitivity without occlusion was higher than that with occlusion in N/N (P<0.01) and the opposite was observed in A/A (P<0.05). No significant sensitivity difference between both conditions was seen in N/A or A/N. In N/A, the points showing a higher sensitivity without occlusion decreased as the sensitivity difference between both eyes increased. CONCLUSIONS: A difference between sensitivities measured with and without occlusion was observed in glaucoma. Owing to the sensitivity disparity between both eyes, monocular sensitivity without occlusion could have been affected differently by binocular interaction.

Comparison of monocular sensitivities measured with and without occlusion using the head-mounted perimeter imo.

PURPOSE: Using a head-mounted perimeter imo that can measure monocular sensitivity with both eyes open, we investigated the difference between monocular sensitivities measured with and without occlusion of the fellow eye and if the difference was influenced by eccentricity. METHODS: Using the perimeter imo, monocular sensitivities with/without occlusion and binocular sensitivity were measured and compared. Three test conditions for monocular sensitivity without occlusion were: with/without a fusional fixation target, and a binocular random single eye test in which the target was randomly presented to either eye and the examinee was not aware of the tested eye. Within the central 25° visual field (VF), 29 points located at the fovea and on the 45°, 135°, 225°, and 315° meridians with 3° intervals were tested. Differences among the four monocular sensitivities with/without occlusion were further evaluated at the fovea, within and beyond the central 5° VF. RESULTS: Sixteen visually normal volunteers (mean age, 28.6 ± 4.6 years) were included in this study. Except at the fovea, monocular sensitivities measured without occlusion were significantly higher than those with occlusion (P < 0.01). No significant difference was seen among the three monocular sensitivities without occlusion (P = 0.82). CONCLUSIONS: Except at the fovea, monocular sensitivities measured with and without occlusion significantly differed. This indicates that without occlusion, binocular interaction is activated and affects not only binocular sensitivity but also monocular sensitivity.

Incidence of side effects of topical atropine sulfate and cyclopentolate hydrochloride for cycloplegia in Japanese children: a multicenter study.

PURPOSE: To investigate the incidence rate and side effects of topical atropine sulfate and cyclopentolate hydrochloride for cycloplegia in children aged 15 years or under. METHODS: This prospective study had been conducted at 9 institutions between April 1, 2016 and March 31, 2017 in patients 15 years old or younger who received either atropine or cyclopentolate for refraction assessment. The investigation included patient's age, symptoms, and whether patients with side effects had any systemic diseases. RESULTS: A total of 811 patients (mean age ± SD, 4.6 ± 2.2 years) received atropine and 71 (8.8%) patients had side effects. Except in patients under two years old, 1% eye drops showed higher incidence rate of side effects than 0.5% and 0.25% eye drops. Side effects most frequently occurred following the initiation of the instillation on the first day. The symptoms included flush (29/71, 40.8%), fever (21/71, 30.0%), and both (11/71, 15.5%). A total of 2238 patients (5.7 ± 3.0 years) used cyclopentolate and 27 (1.2%) (4.0 ± 2.2 years) patients had side effects. The symptoms included drowsiness (10/27, 37.0%), red eye (4/27, 14.8%), fever (3/27, 11.1%), and flush (3/27, 11.1%). CONCLUSIONS: Atropine has a side effect incidence rate 7 times higher than the incidence rate of cyclopentolate. Flush and fever are the most common side effects of atropine and drowsiness is the main side effect of cyclopentolate. These findings should be noted when examining cycloplegic refraction to manage amblyopia and strabismus in children.

Role of fusional convergence amplitude in postoperative phoria maintenance in children with intermittent exotropia.

PURPOSE: To examine the role of fusional convergence amplitude in postoperative phoria maintenance in childhood intermittent exotropia [X(T)]. METHODS: The medical records of 29 children aged 15 years or younger (mean age, 10.8 ± 2.4 years) and treated with monocular recession-resection for X(T) were reviewed retrospectively. The patients' fusional convergence amplitude (break point/total amplitudes), physiologic diplopia, and phoria maintenance (presence/absence of phoria maintenance and ability to maintain phoria) were assessed. The presence of phoria maintenance was confirmed by a cover test, and the ability to maintain phoria was quantified using the Bagolini red filter bar. Correlations of the amplitude size with the presence and ability of phoria maintenance were investigated. RESULTS: A significant correlation was seen between fusional amplitude (break point/total) and ability to maintain phoria at near and at far (break point: P < .05 at near/P < .01 at far; total: P < .05 at near/far). Neither the break point amplitude nor the total amplitude significantly differed between the patients with phoria maintenance and those without it (break point: P = .71 at near, P = .29 at far; total: P = .98 at near, P = .85 at far). Phoria maintenance correlated with the suppression of physiologic diplopia during phoria (P < .01). The deviation angle did not significantly correlate with fusional amplitude either at near (P = .58) or at far (P = .27). CONCLUSIONS: In childhood X(T), fusional amplitude plays a role in enforcing the patient's ability to maintain phoria. However, sufficient fusional amplitude does not guarantee fully functioning fusion if suppression is present during phoria.

Influence of Test Distance on Stereoacuity in Intermittent Exotropia.

AIMS: To investigate influence of test distance on stereoacuity in intermittent exotropia (X[T]) using the same test conditions for both near and far distances. METHODS: Subjects were 38 consecutive patients with X(T). All the patients were between ages 6 and 15 years and had decimal visual acuity of 1.0 or better. Another inclusion criterion was presence of phoric condition at near and far distances. Stereoacuity was measured at a near distance of 40 cm and at a far distance of 5 m. The following test conditions were used for both test distances: separation of the two eyes using polarized glasses, and a target with a random dot pattern. All the stereograms had the same subtended angle of 2.5º, and binocular disparity of 480, 240, 120, and 60 arcsec. We used two stereogram types with crossed and uncrossed disparities. RESULTS: Far stereoacuity of 38 subjects measured with the crossed disparity was significantly worse than near stereoacuity (P<0.05, Wilcoxon signed-ranks test), although 30 (78.9%) of the 38 subjects showed no differences in stereopsis between the near and far distances. Far stereoacuity of 38 cases measured with the uncrossed disparity was significantly worse than at near (P<0.05, Wilcoxon signed-ranks test), although 20 (52.6%) of the 38 subjects showed no differences between stereoacuity at near and far. In comparison of stereoacuity with crossed disparity and uncrossed disparity, stereoacuity with crossed disparity was significantly better than that with uncrossed disparity both at near and far (P<0.05, Wilcoxon signed-ranks test). CONCLUSIONS: Stereoacuity in X(T) was different according to test distance when measured controlling subtended angle of stereogram at both distances. Far stereoacuity was significantly worse than near stereoacuity when measured using test targets with both crossed and uncrossed disparities. Additionally, stereoacuity measured with crossed disparity was better than that with uncrossed disparity at both distances.

Effect of suppression during tropia and phoria on phoria maintenance in intermittent exotropia.

BACKGROUND: Treatment for intermittent exotropia X(T) aims to keep the eye in a phoric position and to maintain the phoria. However, maintenance of phoria is difficult even after treatment, and the cause is unclear. The aim of this study was to investigate the presence of suppression during tropia and/or phoria in X(T), and to determine how the suppression affected patient's ability to maintain phoria. METHODS: Medical records of 89 children with X(T) (mean age, 9.8 ± 2.7 years) were reviewed retrospectively. According to their previous treatment for X(T), the patients were divided into four groups and compared: untreated and under observation only (28 patients), surgical treatment (32 patients), orthoptic training (eight patients) and a combined treatment of surgery and orthoptic training (21 patients). Suppression during phoria was evaluated by a physiologic diplopia test, and suppression during tropia was evaluated by a convergence test or a cover test when fusion broke. Phoria maintenance was achieved if a phoric condition was maintained even when the fusion broke at both near and far. Furthermore, the Bagolini's red filter bar was used to quantitatively assess patient's ability to maintain phoria at near and far distances. RESULTS: No subject only suppressed during phoria. Patients who suppressed under both conditions could not maintain phoria. Suppression under both conditions significantly correlated with phoria maintenance and the ability to maintain phoria (P < 0.01, Fisher's exact probability test). All the patients with a strong ability to maintain phoria did not suppress under either condition. As compared to the surgical treatment group, the combined treatment group had a higher percentage of patients who did not suppress under either condition and could maintain the phoria. Suppression under both conditions also significantly correlated the treatment methods (P < 0.01, Chi-square for the independence test). CONCLUSIONS: Suppression under both tropic and phoric conditions significantly relates to the outcome of patients' phoria maintenance and their ability to maintain a phoric position. Suppression under both conditions is an important indication of whether X(T) shifts to constant exotropia.

[Viewing 3D stereoscopic images in children and adults with and without strabismus: multicenter study in Japan].

PURPOSE: To investigate the ability of patients with strabismus and/or amblyopia to see 3D images. METHODS: A questionnaire survey conducted for children aged 6 to 19 years and adults aged 20 to 39 years on their experience of viewing 3D images (movies, motion attractions, television, games), asking whether they could see stereoscopically, with or without adverse effects. A retrospective investigation of ophthalmological examinations was followed. RESULTS: Of 507 cases, 342 had had the experience of veiwing 3D images. In 212 (62%) cases of strabismus and/or amblyopia, stereopsis was lacking in 17 to 18% of the subjects for movies, in 6 to 7% for attractions, in 32% in children and 50% in adults for television and 23% in children and 17% in adults for games. Adults complained of a higher rate of adverse effects, 65% for movies and 75% for games, as compared with 34% for movies and 26% for games in children(p < 0.01). The lack of stereopsis for games and movies was higher in the subgroup of Fly (-) and convergence insufficiency (p < 0.05). CONCLUSIONS: Since many patients with strabismus and/or amblyopia found some difficulty in stereoscopic viewing, precise examinations for stereopsis and convergence are needed to assess individual aptitude for 3D viewing.

Influence of background complexity on visual sensitivity and binocular summation using patterns with and without noise.

PURPOSE: To investigate how background complexity influences visual sensitivity and binocular summation. METHODS: Using two noise backgrounds (noise-sparse and noise-dense) and two corresponding noise-free backgrounds with the same luminance for each noise background, monocular and binocular thresholds were measured in six visually normal subjects (average age, 27.3 ± 1.1 years). The noise-sparse and noise-dense backgrounds respectively had 312 and 936 white-light dots projected on them-the same size white-light dots (0.431° of visual angle) as those that were used for the white-spot target in the threshold measurement. The target was tested at the fovea and at 3° intervals on the 45°, 135°, 225°, and 315° meridians. A total of 25 locations were tested. RESULTS: The monocular threshold for the noise-dense background was higher than that for its corresponding noise-free background, with significant differences seen at 15° and 18° (P < 0.01). No significant differences in the binocular threshold were seen, either between the noise-dense and its corresponding backgrounds or between the noise-sparse and its corresponding backgrounds. The binocular summation ratios for both noise backgrounds were significantly higher than the ratios for the noise-free backgrounds, and the difference increased with eccentricity, with significances seen at 15° and 18° (P < 0.01). CONCLUSIONS: Only the monocular threshold increases with background complexity. The binocular summation increases with background complexity in the periphery. When the background becomes more complex and the monocular visual processing reaches its limit, binocular interaction functions efficiently.

Influence of target size and eccentricity on binocular summation of reaction time in kinetic perimetry.

To assess how target size and eccentricity affect binocular summation (BS) of reaction time (RT) at suprathreshold level, we measured RT using targets of 0.108° and 0.216° at four eccentricities (0°, 5°, 15°, 25°) in six normal volunteers. The difference between the monocular/binocular RT differentials for both sizes significantly increased in the periphery (P<0.05). The smaller target required significantly longer monocular RT at 25° (P<0.01) and generated greater neural summation than the larger target (P<0.01). This suggests that when monocular function has reached its limit in visual processing in the periphery, BS increases, facilitates visual processing, and shortens binocular RT.

Binocular summation of detection and resolution thresholds in the central visual field using parallel-line targets.

PURPOSE: To investigate the effect of thresholds on binocular summation for detection and resolution of parallel-line targets of different widths. METHODS: The automatic perimeter Octopus 201 (Haag-Streit International, Köniz, Switzerland) combined with a modified haploscope device and targets consisting of parallel lines that were 10' (10' target), 2.5' (2.5' target), or 1.43' (1.43' target) of visual angle in width and apart were used to measure the thresholds for monocular-binocular detection and resolution of the targets under the same binocular fusion stimulation conditions in seven young adults with normal vision. The custom program in the automatic perimeter was used to test 27 points. Seventeen of the 27 points were located in the central 6 degrees of visual field and 10 on the horizontal meridian subtending visual angles of 8 degrees , 10 degrees , 12 degrees , 16 degrees , and 20 degrees . RESULTS: The resolution threshold was significantly higher than the detection threshold for the 2.5' and 1.43' targets (P < 0.01 by Bonferroni/Dunn test). Furthermore, as the target width decreased to 2.5' or 1.43', the binocular summation ratio for the resolution threshold increased significantly over that for the detection threshold, with increasing distance from the fovea (P < 0.01 by Wilcoxon signed ranks test). CONCLUSIONS: Binocular summation for detection and resolution thresholds varies as a function of the width of a parallel-line target. The difference between binocular summation ratios for detection and resolution thresholds increases with decrease in target width and increase in eccentricity from the fovea. Binocular interaction plays an important role in the task of recognizing a high-resolution target in the parafoveal area.

Properties of receptive field on binocular fusion stimulation in the central visual field.

BACKGROUND: Visual information projected onto corresponding points on the right and left retinas converges on the binocular cells in the visual cortex. The aim of this study is to investigative the characteristics of the receptive field for binocular stimulation in the central visual field of normal-sighted human subjects. METHODS: We investigated the receptive field for binocular stimulation under fusion conditions by combining the Octopus 201 with the space synoptophore. We measured binocular and monocular sensitivities while the fusion patterns were projected onto the Octopus 201 cupola, using the space synoptophore. We designed a new program to test 37 points in the central 6 degrees visual field. Six target sizes were tested: the white-spot targets of 0.054 degrees, 0.108 degrees, 0.216 degrees, 0.431 degrees, 0.862 degrees and 1.724 degrees projected diameters. RESULTS: The threshold energy necessary for binocular stimulation was lower than that for the monocular stimulation in all subjects. This difference was more obvious on the test points that were more distant from the fovea when target sizes of 0.054 degrees and 0.108 degrees were used. The amount of binocular summation ratio was highest for target size 0.054 degrees in each stimulus area in the central 6 degrees of the visual field. When we measured binocular summation using target sizes larger than 0.108 degrees, the result was the constant summation. CONCLUSIONS: The size of the receptive field for binocular stimulation is smaller than monocular stimulation under the same fusion condition. The amount of binocular summation varies as a function of target size.