Binocular Status Research Articles

Clinical features and refractive profile of Brown syndrome

ABSTRACT Clinical Significance Understanding the refractive profile, amblyopia prevalence, binocular status, and head position in patients with Brown syndrome help clinicians become more familiar with this syndrome. Background Brown syndrome is identified as an active and passive restricted elevation of the eye in adduction. There is little information on clinical features, including refractive status, amblyopia, abnormal head posture (AHP), and types of deviation in these patients. Methods This study retrospectively evaluated records of 100 Brown syndrome patients from 2015 to 2022 at Farabi Eye Hospital, Iran. Results The mean age was 6.99 ± 6.33 years, including 48 (48%) males. A congenital source was found in 74 (74%) and 96 (96%) patients had unilateral involvement. The mean CDVA for the affected and non-affected eyes were 0.05 ± 0.11 and 0.03 ± 0.06 logMAR, respectively (P = 0.31). In unilateral cases, hyperopia, myopia, and emmetropia were observed in 55 (57.29%), 2 (2.08%), and 39 (40.63%) affected eyes, respectively. The most common type of deviation was pure hypotropia, which was found in 53 (53%) cases, followed by ‘combined exotropia and hypotropia’ observed in 26 (26%) patients. The mean angle of hypotropia and horizontal deviation in the primary position at distance was 12.10 ± 8.50 and 8 ± 13.20 prism dioptre, respectively. A V-pattern was found in 76 (76%) patients. Amblyopia was observed in 13 (21.67%) of 60 cooperative patients, and AHP was noticed in 66 (66%) patients, in which “combined chin up and contralateral face turn” was the most common type. Conclusion About 75% of cases were congenital, 50% had pure hypotropia, 75% showed V-pattern, 20% had amblyopia, and AHP was observed in 67% of patients. The remarkable prevalence of amblyopia alongside the high occurrence of AHP should alert clinicians to carefully assess patients with Brown syndrome for sensory fusion and amblyopia.

Does Surgical Resection of Horizontal Extraocular Muscles Disrupt Ocular Proprioceptors?

It has been promoted that disturbance of ocular proprioception may play a role in the pathogenesis of concomitant strabismus and other types of oculomotor anomalies. The aim of the study was to obtain knowledge about how surgical foreshortening of the myotendinous region potentially affects the proprioceptors that resides in this area of the muscles and to test the hypothesis that avoiding disruption of ocular proprioceptors result in a more favorable long term postoperative result. The distal end of the lateral and medial rectus muscles from patients with manifest concomitant strabismus with a deviation of ≥15 prism diopters (PD) were collected during strabismus surgery and processed for light microscopy by standard histochemical techniques. Histological analysis served to differentiate between the tissue samples containing pure tendon, versus samples containing the myotendinous junction. Criteria for successful outcome was defined as a residual angle of deviation less than 10 PD. The binocular status of the patient was measured pre- and post-operatively at 6-months of follow-up. Tissue samples from 43 patients (median age 19 years old, range 3-58 years) were collected during surgery. Twenty-six of the samples contained pure tendon, while 17 contained muscle fibres. The evolution of the post-operative result revealed a moderate reduction in the residual angle of deviation in patient-samples containing pure tendon. In contrast, the residual angle of deviation clearly increased in patient-samples containing muscle fibres. The difference between the two groups reached statistical significance after 6 months. Successful outcome was found to be more than three times more likely in cases where surgery was performed in pure tendon, compared to muscle fibres. The current study supports the hypothesis that avoiding disruption of ocular proprioceptors, located in the distal myotendinous region, results in a more favorable postoperative result.

A new method of amblyopia treatment in children with unstable central and eccentric fixation using biofeedback

Purpose. To develop a new method of amblyopia treatment in children with unstable central and eccentric fixation by centralizing visual fixation and increasing retinal photosensitivity in the macular region using biofeedback. Material and methods. The study included 27 patients (27 eyes) with amblyopia of various origins, aged 5 to 17 (averagely 9.15 ± 3.19 years), who were able to perform training sessions on the MP-3 Nidek microperimeter (Japan). In addition to standard examination, all patients underwent binocular status assessment using a four-point test, macular electroretinography, microperimetry, optical coherence tomography (OCT). The treatment, carried out on the microperimeter using visual (flickering checkerboard pattern) and sound signal biofeedback, consisted of 10—15 sessions, 10—12 minutes each. All patients were examined before treatment cycle, immediately upon the end of the cycle, and also 1 and 3 months after it. Results. Preliminary results showed an increase in best corrected visual acuity (BCVA) from 0.41 ± 0.24 to 0.68 ± 0.27 (33.9 %), the photosensitivity of the retina in the fovea increased from 27.07 ± 3.90 to 29.8 ± 3.3 dB (10 %), fixation density in the central region from 59.80 ± 31.08 to 72.05 ± 34.5 %(20.4 %) with its amplitude decreased by more than two times. After treatment, unstable central fixation changed to stable central fixation in all cases. With eccentric fixation, the fixation point shifted closer to the central region, and fixation characteristics improved in 75 % of cases. The obtained results retained throughout the observation period which lasted up to 3 months. Conclusion. The proposed new treatment method of amblyopia with impaired fixation of various degrees proved to be effective and safe and can be recommended for use in pediatric patients.

Preoperative binocular vision characteristics in the age-related cataract population

BackgroundThis study is the first part of the “Binocular Vision Anomalies after Cataract Surgery” study that aimed to investigate the impact of cataract surgery on binocular vision status in adults with age-related cataract. This study aimed to investigate the preoperative binocular vision status of participants with age-related cataract.MethodsPatients who elected to undergo bilateral cataract surgery (≥50 years of age) were recruited. Clinical measures of binocular vision including stereopsis, ocular alignment, fusional vergence, vergence facility, convergence amplitude and a symptom survey related to binocular vision anomalies were administered. A detailed classification protocol was established to identify the presence of binocular vision anomalies. The frequency of specific binocular vision anomalies and normative data of binocular vision measures were reported.ResultsA total of 73 subjects were evaluated. No strabismus was detected in the cohort. Non-strabismic binocular vision anomalies were detected in 24 subjects (32.9%), of whom 18 (24.7%) had convergence insufficiency, 3 (4.1%) had basic exophoria, 2 (2.7%) had convergence excess, and 1 (1.4%) had fusional vergence dysfunction. Decreased vergence facility and convergence amplitude were more common compared to the pre-presbyopes (P < 0.01).ConclusionBinocular vision problems, especially convergence insufficiency, are common in the adults with age-related cataract. The study results demonstrate that the lack of normative binocular vision data for the presbyopic population is a significant gap in the literature and suggest the need for a study of normative data for this population.Trial registrationThe study was registered at ClinicalTrials.gov (NCT03592615, USA).

Binocular visual deficits at mid to high spatial frequency in treated amblyopes

SummaryAmblyopia (lazy eye) is a neurodevelopmental disorder of vision with no ocular pathology. The loss of vision in the amblyopic eye is assumed to be the main deficit in amblyopia, which has resulted in visual acuity (VA) being the primary outcome measure for treatment. Here we used a binocular orientation combination task to quantitatively assess the binocular status by measuring the binocular balance. We set out to determine whether amblyopes who reach the acuity-based end point have a residual binocular imbalance. Our results suggest that even amblyopes who have regained normal acuity have residual binocular deficits over a wide range of spatial frequencies. A further control study suggests that these binocular deficits could not be explained by any residual contrast sensitivity deficits of the amblyopic eye. Consequently, amblyopia is not the primary problem and VA is not the appropriate end point measure.

Is the Current Treatment of Lazy Eye Based on a False Premise?

Amblyopia (lazy eye) is a neurodevelopmental disorder of vision with no ocular pathology. The loss of vision in the amblyopic eye is assumed to be the main deficit in amblyopia, which has resulted in visual acuity being the primary outcome measure for treatment. Here we used a binocular orientation combination task to quantitatively assess the binocular status, at a stage before stereopsis, by measuring the binocular balance. We set out to determine whether amblyopes who reach the acuity-based endpoint have a residual binocular imbalance. Our results suggest that even amblyopes who have regained normal acuity have residual binocular deficits over a wide range of spatial frequencies. A further control study suggests that these binocular deficits could not be explained by any residual contrast sensitivity deficits of the amblyopic eye. Consequently, amblyopia is not the primary problem and visual acuity is not the appropriate endpoint measure.

Unexpectedly high prevalence of asthenopia in Australian school children identified by the CISS survey tool

BackgroundTo date there have been few systematic attempts to establish the general prevalence of asthenopia in unselected populations of school-aged children. Thus, the aim of this study was to determine whether the incorporation of Borsting et al’s 2003 Revised Convergence-Insufficiency Symptom Survey (CISS) into a general school vision screening could aid in the identification of children with visual discomfort and indicate the need for further investigation.MethodsVision screening of an unselected middle school population investigated and analysed the incidence of self-reported nearwork-related visual discomfort via the CISS along with distance and near visual acuities plus non-cycloplegic autorefraction using a Shin-Nippon NVision-K 5001.ResultsOf the 384 unselected students approached in Grades 6–9, 353 participated (92.2%, mean 13.2 ± 1.4 years). The mean CISS score for the population without amblyopia and/or strabismus (96.0% of all students) was 16.8 ± 0.6, i.e., 45% of students in this cohort had CISS scores greater than one standard deviation above the mean found by Borsting et al. in 2003 during their validation study of the CISS on 9 to 18 year old children without binocular anomalies. Regression analyses indicated significantly higher (p < 0.001) mean CISS scores for the 3.2% who were hyperopes ≥ + 2.00D by non-cycloplegic autorefraction (27.7 ± 14.7) and for those who were amblyopic (24.3 ± 6.6) or strabismic (34.0 ± 9.8). The mean CISS score of 31.6 ± 9.0 for non-amblyopic/strabismic students having near vision poorer than 0.1 LogMAR was significantly higher (p < 0.001) than for those with good acuity.ConclusionThe most important finding of this study was the high incidence of asthenopia in an unselected population and that refractive status per se was not a major contributor to CISS scores. The results highlight the usefulness of the CISS questionnaire for assessment of visual discomfort in school vision screenings and the need for future exploration of near binocular vision status as a potential driver of asthenopia in school students, especially given current trends for frequent daily use of computers and handheld devices and necessarily prolonged accommodative-convergence effort at near, both at school and at home.

Effect of Pupil Size and Binocular Viewing on Accommodative Gain in Emmetropia and Myopia

ABSTRACT Purpose To evaluate the differences in accommodative gain in response to different accommodative stimuli and determine the effects of pupil size, binocular viewing, and inherent eye refraction on accommodative gain. Methods This study enrolled 47 healthy young adults (emmetropia: 21 eyes, myopia: 26 eyes). Refractive value and pupil size during accommodative stimulus were measured using an open-viewing type auto-refractor (Grand Seiko WAM-5500). The subject was continuously presented with six stimuli (0D, 1D, 2D, 3D, 4D, and 5D) in front of the eye. Measurements were performed under three conditions. Condition 1: Monocular status with complete occlusion of the non-viewing eye; Condition 2: Monocular status with occlusion of the non-viewing eye by translucent occluder; Condition 3: Binocular status. Results In the emmetropia group, there was no significant difference in accommodative gain between conditions 1 and 2 (p > .05), but conditions 2 and 3 were significantly different (p < .05). In the myopia group, accommodative gain was significantly different between conditions 1 and 2 with stimuli 3D, 4D, and 5D (p < .05), but conditions 2 and 3 were not significantly different (p > .05). Conclusions The effects of pupil size and binocular viewing on accommodative gain differed between emmetropia and myopia.

Comparison of conventional and Hang-back methods of inferior oblique recession in V-pattern strabismus with inferior oblique overaction.

To compare outcomes of conventional and Hang-back methods of inferior oblique (IO) recession in V-pattern strabismus with inferior oblique overaction (IOOA). Comparative randomized study was conducted consisting of 50 patients, age 6 to 35y having V-pattern strabismus [>15 prism diopter (PD)] with IOOA. They were divided equally in two groups and underwent IO recession, group A by conventional method and group B by Hang-back method. Parameters evaluated were reduction in V-pattern and IOOA, shift in torsion, improvement in binocular status. Success was a residual V-pattern of less than 10 PD at 1y of follow up. The mean V-pattern preoperatively and postoperatively at 1y was 24±5.4 PD and 4.2±3.51 PD in group A and 23.44±6.44 PD and 5.76±3.8 PD in group B respectively. The mean reduction in V-pattern was 20±6.78 PD in group A and 18.2±5.48 PD in group B. The mean correction of IOOA was 18.48±3.13 PD in group A and 16±2.93 PD in group B. Mean shift in extorsion was 3.08±1.8 degree in group A and 3.72±2.14 degree in group B. Both the procedures achieve a significant and comparable reduction in V-pattern and IOOA. Hang-back recession being a landmark free surgery eliminates the need for intrascleral suturing thereby reducing the risk of scleral perforation with possible postoperative adjustment of muscle. It may be considered as a good alternative for IO recession in patients of V-pattern strabismus with mild to moderate amount of IOOA.

Study of correlation between stereopsis and retinal nerve fiber layer thickness in cases of glaucoma

BackgroundGlaucoma is an important and common optic neuropathy characterized by progressive loss of retinal ganglion cells and associated morphological changes to the optic nerve and retinal nerve fiber layer (RNFL). The most common assessment of visual function in glaucoma uses perimetric measurements of visual sensitivity. Only few studies have evaluated the binocular function in patients with glaucoma. This study was taken up to establish the correlation of RNFL thickness, in glaucoma, with near and distance stereopsis. MethodsThis pilot, cross-sectional observational study included 100 diagnosed cases of glaucoma and 100 normal participants as controls, studied over a period of one year. The records of all the participants were checked, and only established cases of glaucoma after fulfilling the inclusion and exclusion criteria were included. Analysis of the RNFL using spectral-domain optical coherence tomography was carried out. All the participants were thereafter evaluated for stereoacuity by near (at 40 inches) and distance (at 3 meter) Randot stereoacuity charts. ResultsThere was a negative correlation between the RNFL thickness and the absolute value of streoacuity (-0.303 for distance versus -0.101 for near in cases and -0.308 for distance and -0.416 for near in control group), decreasing the actual functional stereoacuity, therefore the cases with lower RNFL thickness had lower stereoacuity both for distance and near, however it was statistically significant only for distance (p=0.002). ConclusionFunctional aspects, such as stereoacuity, may also be affected in the glaucoma because of decrease in RNFL thickness. Therefore, binocular status should also be evaluated in cases of glaucoma.

Awareness among medical students regarding the binocularity level in the course of future specialty choice.

Vision standards exist in many occupations with particular reference to medical science. The presence of a sufficient level of binocular vision is especially important in surgical specialty to perform visually demanding procedures. The purpose of this study was to reveal the level of awareness of one's binocular status among medical students, and the significance of having binocular vision in terms of specialty choice. self-constructed questionnaire was given to all subjects enrolled in the study. The first group comprised 53 students from the second and third year of the Medical University of Lodz, who then underwent an ophthalmological examination with binocularity assessment. The second group included 57 students of the last years of the Medical Faculty, who did the same survey and outlined how the ophthalmology course improved their knowledge of stereoacuity and vision requirements for the chosen specialty. Statistical analysis was performed using Person's χ2 test. Overall, 32% (N = 17) of the students from the first group and 84% (N = 48) from the second group stated to be familiar with the term "binocularity" and its importance in performing surgical procedures. The awareness of the existing occupational contraindications related to low visual acuity and binocularity was declared by 16% (N = 9) and 54% (N = 31) of the subjects included in each group, respectively. University lectures were indicated as the main source of knowledge by 28% (N = 15) of the individuals from the first group and by 59% (N = 39) from the second group. The ophthalmology course was considered to be sufficiently covering the basics needed for the future doctor by 34 resident physicians (60%). The medical students' awareness of their own binocular status appears low. There is a strong need for implementing at least some quality standards for visual assessment to decide if a given student has an adequate eye function to participate in surgical procedures. Med Pr. 2020;71(1):9-16.

Binocular vision 5: Comitant heterotropia and its adaptations

Dr Fergal Ennis continues our series on the assessment of binocular status with a detailed look at comitant heterotropia, a tropia that is not dependent on position of gaze.

Ocular effects of virtual reality headset wear in young adults

Virtual Reality (VR) headsets create immersion by displaying images on screens placed very close to the eyes, which are viewed through high powered lenses. Here we investigate whether this viewing arrangement alters the binocular status of the eyes, and whether it is likely to provide a stimulus for myopia development. We compared binocular status after 40-minute trials in indoor and outdoor environments, in both real and virtual worlds. We also measured the change in thickness of the ocular choroid, to assess the likely presence of signals for ocular growth and myopia development. We found that changes in binocular posture at distance and near, gaze stability, amplitude of accommodation and stereopsis were not different after exposure to each of the 4 environments. Thus, we found no evidence that the VR optical arrangement had an adverse effect on the binocular status of the eyes in the short term. Choroidal thickness did not change after either real world trial, but there was a significant thickening (≈10 microns) after each VR trial (p < 0.001). The choroidal thickening which we observed suggest that a VR headset may not be a myopiagenic stimulus, despite the very close viewing distances involved.

Visual and binocular status in elementary school children with a reading problem

PurposeThis descriptive study provides a summary of the binocular anomalies seen in elementary school children identified with reading problems. MethodsA retrospective chart review of all children identified with reading problems and seen by the University of Waterloo, Optometry Clinic, from September 2012 to June 2013. ResultsFiles of 121 children (mean age 8.6 years, range 6–14 years) were reviewed. No significant refractive error was found in 81% of children. Five and 8 children were identified as strabismic at distance and near respectively. Phoria test revealed 90% and 65% of patients had normal distance and near phoria. Near point of convergencia (NPC) was <5cm in 68% of children, and 77% had stereoacuity of ≤40seconds of arc. More than 50% of the children had normal fusional vergence ranges except for near positive fusional vergencce (base out) break (46%). Tests for accommodation showed 91% of children were normal for binocular facility, and approximately 70% of children had an expected accuracy of accommodation. ConclusionFindings indicate that some children with an identified reading problem also present with abnormal binocular test results compared to published normal values. Further investigation should be performed to investigate the relationship between binocular vision function and reading performance.

On the Maintenance of Normal Ocular Dominance and a Possible Mechanism Underlying Refractive Adaptation.

Do humans with uncorrected anisometropia who have not developed anisometropic amblyopia exhibit a shift in ocular dominance nonetheless, reflecting a more subtle form of deprivation? Also, is such a change in dominance, if it occurs, permanent or could it be rectified by an extended period of optical correction? A total of 25 normal controls (27.5 ± 2.1 years; mean ± SD); 28 anisometropes (20.7 ± 5.6 years) who were fully corrected for more than 16 weeks prior to this investigation; and 24 anisometropes who had never been corrected (21.2 ± 9.8 years) participated in this study. Sensory eye dominance of observers was measured using the binocular phase combination paradigm to find an interocular contrast ratio at which the contributions of each eye to the binocularly fused percept were equal (i.e., the balance point measure of ocular dominance). Controls exhibited a balance point close to unity (0.91 ± 0.05), while the two groups of anisometropes exhibited a clear binocular imbalance (uncorrected anisometropes, 0.51 ± 0.28; corrected anisometropes, 0.70 ± 0.19); both were significantly different from controls (P < 0.001). The imbalance was less severe in corrected anisometropes compared with uncorrected anisometropes (P = 0.004). We find that anisometropia is associated with an ocular imbalance even in the absence of amblyopia. This abnormality is weaker in anisometropes who have worn an optical correction for some time, suggestive that a better optical status leads to a better binocular status.

The influence of a prolonged interoperative period on binocular vision after bilateral cataract extractions.

To evaluate the influence of the extent of the interoperative period on binocular vision function in patients after consecutive bilateral cataract extractions and intraocular lens implantation. The study included patients operated due to bilateral cataract. Presence of asthenopic symptoms, distance and near squint angle, fusional amplitudes, stereopsis, and convergence were evaluated. Preoperative, interoperative, and postoperative differences in best-corrected visual acuity between eyes were also noted. Multivariate analysis was conducted in order to establish the relation between the interoperative period and binocular status. The study included 104 patients (74 female, 30 male, mean age 69.9 years, range 32-88). Mean interoperative period was 20.3 ± 12.9 months, range 1.5-47.7. Prolongation of the interoperative interval had a significant negative impact on stereopsis measured by TNO (R2 = 0.215, p = 0.001) and Randot (R2 = 0.179, p = 0.001) stereotests, as well as for near point of convergence (R2 = 0.09, p = 0.002). It was also related, but not independently, to reduction in fusional amplitudes, mainly for distance (R2 = 0.18, p = 0.001 for divergence and R2 = 0.12, p = 0.001 for convergence). Asthenopic symptoms were reported by 17 (16.3%) patients. The incidence of exophoria was significantly (p = 0.002) higher in patients with an interoperative interval longer than 24 months. The length of the interoperative period influences the status of binocular vision in patients after bilateral cataract extraction. It is also connected with an increased number of patients with asthenopic symptoms and exophoria.

Long-Term Postoperative Development of Stereopsis in Infantile Exotropia.

The purpose of this study was to investigate serial changes in stereopsis in patients with infantile exotropia during follow-up testing. This was a retrospective case series. Twenty-one patients diagnosed with exotropia before age 1 who underwent surgery and examination for stereopsis at least 3 times after surgery were included in this study. Clinical records of the patients were retrospectively reviewed. Patients with binocular sensory test results exceeding 8 prism diopters (PD) of exodeviation or 5 PD of esodeviation were excluded from the study. The change in binocular status and associated clinical features were assessed in all patients. The patients were followed up for a mean of 54 months. The average ages at the initial and final stereopsis tests were 4.7 years and 7.1 years, respectively. The mean angle of deviation at the final stereopsis test was 1.33 ± 2.48 PD at distant and 0.86 ± 2.24 PD at near. Initial stereopsis ranged from 3000 (including no stereopsis) to 60 arc seconds. Three patients had excellent stereopsis of 60 arc seconds in the initial test. Five of the other 18 patients initially showed gross stereopsis but developed excellent stereopsis of 60 arc seconds by the final test. Even if patients do not show excellent stereopsis of 60 arc seconds in an initial diagnostic test, they should receive regular screenings as they age to assess the development of stereopsis in infantile exotropia.

Disorders of Accommodative Convergation and Accommodation (AC/A) Relations at Traumatic Brain Injury.

Dear Editor, We read with interest the article by Serdarevic (1) regarding the disorders of accommodative-convergence/accommodation (AC/A) relation in patients with traumatic brain injury (TBI). Similar to the results of previous studies, the author found that the individuals with TBI may have various degrees of convergence insufficiency (CI) (2, 3). Traumatic brain injury (TBI) is defined as an alteration in brain function, or other evidence of brain pathology, caused by an external force. It can affect multiple aspects of vision, where mild TBI frequently leads to different disruptions in visual functioning, while moderate or severe TBI often cause structural lesions (4). There are two basic mechanisms of TBI: blast-related (BR TBI) which is caused by the blast wave itself or by direct head trauma caused by events surrounding the blast and non-blast-related (NBR TBI) which are caused by direct head trauma (5). The recent reports show that majority of patients with mild TBI can have different visual abnormalities, including oculomotor dysfunction (up to 90%) (2, 3), binocular vision (up to 29%) (2, 3) and visual field deficits (up to 39%) (2). Convergence insufficiency is an eye coordination and alignment problem that can be observed in 43 to 46% patients with mild TBI (2, 3). Moderate and severe TBI might additionally lead to ocular motor palsies, optic neuropathies, and orbital pathologies (4) However, CI without simultaneous visual or vestibular dysfunctions can be observed in only 9% of the visually symptomatic TBI patients (3). The mechanism of TBI injury can also be a prognostic factor, where light sensitivity is reported more often in BR TBI patients (67%) than in NBR TBI patients (33%). However, saccadic dysfunction is measured more often in NBR TBI patients (85%) than in BR TBI patients (58%) (5). Patients with TBI can suffer from various physical and mental disorders, therefore the treatment of patients with TBI with presenting signs of vision impairment can be extremely complicated. The new concept for treatment of these patients focuses on 4 main problems that need to be addressed: 1. Basic optometric vision examination (includes: assessment of refractive status, binocular status and ocular health status); 2. Oculomotor-based vision problems (refers to more comprehensive investigation and testing related to the specific oculomotor-based vision problems–accommodative vergence and the AC/A ratio, fusional vergence ranges at distance and near, phorias at distance and near, vergence flexibility at near, and the near point of convergence); 3. non-oculomotor-based vision problems (photo sensitivity, motion sensitivity, vestibular problems, visual field defects and various a range of deficits in visual information processing and perception) and 4. non-vision-based problems (refers to depression, fatigue, cognitive impairment, behavioral problems, postural problems, attentional problems and neurological problems). These problems tend to confound and complicate the vision examination procedures and can lead to inadequate treatment and result interpretation (6). For these reasons, we would kindly ask the authors to perform the correlations for Glasgow Coma Scale (GCS) scores, severity and mechanism of TBI, time between the injury and symptoms onset, refractive status and visual acuity, type of visual field deficits, presence of reading disorders, light sensitivity, presence of non-oculomotor-based vision problems and non-vision-based problems, type and length of visual rehabilitation with AC/C ratio. Without these information’s it would be difficult to hypothesize AC/C ratio changes as isolated consequence of CI as a result of TBI. These findings will significantly contribute to the papers scientific value and contribution. Overall we agree with Serdarevic that CI presents important visual deficit in patients with TBI. Other systemic and ophthalmic factors such as severity of brain injury, visual acuity and visual field deficits, together with presence of non-oculomotor-based vision problems and non-vision-based problems should be carefully monitored too.

To evaluate stereoacuity in patients with acquired esotropia and to determine factors associated with favourable outcomes.

Aim:To evaluate stereoacuity in patients with acquired esotropia and determine the factors associated with favorable outcomes.Materials and Methods:A total of 68 subjects aged 6 years and above were included in the study. Thorough clinical evaluation including binocular status examination using the Bagolini-striated glass test, The Netherland Organization (TNO), and Randot stereo test were done. The subjects were divided into two groups 1 and 2, based on the amount of deviation. Statistical analysis of the result was performed.Result:The duration of misalignment in the group with deviation less than or equal to 8 prism diopters (PD) was 1.49 ± 0.86 years, whereas in the group with deviation more than or equal to 10 PD was 4.64 ± 2.99 years (P = 0.000). Among the subjects in group 1, 89.5% achieved fusion and 52.6% had stereoacuity on both TNO and Randot, whereas in group 2 40% achieved fusion and 3.3% stereopsis on both TNO and Randot (one case with only coarse stereopsis). A subanalysis within group 1 revealed a statistically significant difference for the duration of misalignment (P = 0.02), but a marginal difference for the amount of deviation (P = 0.3).Conclusion:A horizontal deviation up to 8 PD was compatible with stereopsis. Also, the duration of constant misalignment affects the attainment of stereopsis despite successful realignment.

The Stability of the Monofixation Syndrome

To determine etiology, characteristics, and stability of the monofixation syndrome (MFS) in a chart review of 63 consecutive patients in a private practice of pediatric ophthalmology. Retrospective, consecutive chart review. The charts of 63 consecutive patients with MFS, encountered from 2007-2012 followed for a minimum of 3 years were included. Best visual acuity, motor angle deviation at near, fusion, and stereoacuity as recorded on the most recent visit during the follow-up period were examined. Stability of the MFS was determined by comparing the dates of diagnosis with the last examination for those patients who remained stable. Decompensated patients were also studied for characteristics and results of secondary surgery. The etiology of the MFS was esotropia in 58 (92.1%), anisometropia in 2 (3.2%), and exotropia in 3 patients (4.8%). The majority of patients, 57 of 63 (92%), had stable MFS for a mean of 13.9 years. Six esotropic patients decompensated after a mean of 6 years; 5 of these patients were restored to MFS by secondary surgery and 1 spontaneously recovered. Five patients were found to have improved stereoacuity to 60 arc seconds or better by the end of the study. The MFS is a relatively stable binocular status during the first 2 decades of follow-up. A small percentage of patients decompensated, requiring secondary surgery to restore the MFS binocular status. A similar small percentage of MFS patients developed a higher grade of stereoacuity when followed for a sufficient interval of time.