Accommodative Convergence Research Articles

Intermittent exotropia: a novel surgical algorithm based on a postocclusion distance-near relationship

For the preoperative evaluation of patients with intermittent exotropia, prior studies have revealed that prism alternate cover testing at distance and at near should be performed after a period of monocular occlusion, and that the use of a reading add at near helps to exclude accommodative convergence. Using these evaluation techniques, a performance improvement project was undertaken to evaluate a dosage-modification algorithm created to improve outcomes with bilateral lateral rectus recession surgery.

Forty-five Years of Studying Intermittent Exotropia — What Have I Learned? The WSPOS Keynote Strabismus Lecture, October 3, 2020

ABSTRACT There are three keys to understanding how the new way of classifying and treating intermittent exotropia (IXT) differs from Burian’s classic classification. First, the assumption that lateral rectus surgery selectively affects the distance deviation, recess/resect procedures affect the distance and near equally, and that medial rectus surgery selectively affects the near deviation, are false assumptions. Second, AC/A ratios in IXT can be calculated in all the usual manners, provided that any near measurement used in the calculation be made after prolonged monocular occlusion to eliminate the contaminating effect of the Scobee phenomenon. Third, the use of +3 diopter (D) lenses at near and prolonged monocular occlusion are not interchangeable and work on different mechanisms, the former on accommodative convergence and the latter on fusional convergence. All patients with IXT should have a measurement taken after prolonged monocular occlusion, as well as while fixating on a far distant outdoor target prior to surgery, which should target the largest angle measured.

Changes to Visual Parameters Following Virtual Reality Gameplay.

Introduction:Virtual reality (VR) gameplay is popular with a range of games and educational resources available. However, it puts high demands on the visual system. Current evidence shows conflicting impacts on visual parameters. Therefore, this study explores the changes to vision following VR gameplay.Methods:The study was conducted at the School of Health Sciences, University of Liverpool. All participants had binocular vision with good visual acuity and no manifest strabismus. Participants were assessed before and after playing 15 minutes of the VR game Beat Saber, which incorporated convergence and divergence movements. Clinical assessments including near point of convergence (NPC) and near point of accommodation (NPA) using the RAF rule; accommodative convergence to accommodation (AC/A) ratio; motor fusion using the prism fusion range (at 33cm), accommodation facility using +2.00/–2.00DS flipper lenses, and stereoacuity using the Frisby stereo test were assessed before and after playing.Results:Seventy-eight participants (19–25 years old) were included in the study, with 16 males and 41 females respectively. The breakpoint of convergence reduced by 0.5 cm (p = 0.001). The binocular accommodative facility improved by 2 cycles per minute (cpm); p = 0.004. The mean, near horizontal prism fusion range (PFR) base break and recovery points both worsened by of 5.0 dioptres (p = 0.003), whereas the mean near horizontal PFR base in recovery point improved by of 4.0 dioptres (p = 0.003).Discussion:The study validated previous findings as VR gameplay over-exercised and fatigued convergence muscles, but to a small degree. The VR experience improved the participants’ ability to change focus quickly and improve accommodation, as well as the divergence function of the eye. However, as the participants were retested directly after the VR gameplay, the findings were limited to short term effects on vision.

Binocular vision parameters in chronic heavy alcoholics: Short-term outcomes of alcohol detoxification

Background: Alcohol consumption is rising in developing countries such as India, and alcohol addiction has systemic and ocular impacts. This study aimed to investigate the binocular functions of chronic heavy alcoholics before and after alcohol detoxification.
 Methods: A prospective before–after study was designed and conducted at Treda De-Addiction Centre, Bengaluru, India. Males in the age range of 30–40 years who had been alcohol addicts for more than six years and met the inclusion criteria were recruited. We performed a routine optometric examination followed by detailed binocular vision assessment, including accommodative, vergence, and oculomotor tests on the first day of rehabilitation and one month after initiation of rehabilitation.
 Results: Twenty-five males with of the age (mean ± standard deviation [SD]) 36.24 ± 4.33 years were evaluated. The pre- and post-detoxification mean ± SD of the monocular (right eye: 5.98 ± 3.50, 6.60 ± 3.49; left eye: 6.18 ± 3.69, 7.10 ± 3.78) and binocular accommodative facility (7.10 ± 3.93, 7.40 ± 4.51) did not change significantly (all P > 0.05). Eighteen (72%) of the participants had non-strabismic binocular vision anomalies (NSBVA), among whom the accommodative infacility and convergence insufficiency were higher in frequency and remained constant after alcohol detoxification. Furthermore, the binocular vision parameters showed no statistically significant difference between the pre- and post-detoxification values (all P > 0.05).
 Conclusions: The binocular vision parameters did not change significantly after one month of alcohol detoxification in the chronic heavy drinkers. Most long-term alcoholics had NSBVA with no change after rehabilitation, indicating that short-term alcohol detoxification may not aid in the recovery of binocular parameters. However, further validation is required. Assessing the impact of vision therapy in addition to a longer period of abstinence can confirm or refute the persistence of observed effects of chronic alcohol consumption on binocular functions and NSBVA in this population.

Treatment of partially accommodative esotropia in children using a medial rectus muscle fenestration technique

To report the results of bilateral fenestration of the medial rectus muscle in cases of partially accommodative esotropia in pediatric patients. In this fenestration technique, two splitting incisions are made by blunt dissection parallel to the muscle fibers on the superior and inferior borders of the medial rectus muscle, leaving a thin strip of muscle fibers on each edge. The wide, central part of the muscle is excised from its insertion to a point 5-8 mm from the insertion, depending on the angle of the esotropia. Sutures are not used in this procedure. Children with partially accommodative esotropia and no high ratio of accommodative convergence to accommodation who underwent surgery from February 2018 to August 2019 were prospectively enrolled. The success rate was defined as alignment within 8 prism diopters of orthotropia at the last follow up. A total of 61 children were included. The procedure was well tolerated by patients and reduced the angle of esotropia for distance from 22.20Δ ± 4.22Δ to 2.72Δ ± 4.71Δ (P<0.001) and caused no incomitance or distance-near disparity. Satisfactory horizontal alignment defined as alignment within 8Δ of orthotropia at distance was achieved in 88% of the cases at 3-6 months' follow-up. There were no overcorrections. In our study cohort, the fenestration technique reduced the angle of deviation in cases of partially accommodative esotropia.

Comparing proximal convergence ratio in myopes.

Aim: To determine if there is a difference at all in proximal convergence to accommodation ratio (PC/ A) between 2 myopic groups. Group A: -0.50D < SE < 3.00D, SE: spherical equivalent, D: Diopter) and Group B (-3.00D SE and above). Patients and methods: In this prospective observational study, 24 consecutive patients with myopia between -0.50D < SE < 3.00D were included in group A and 27 consecutive patients with myopia > -3.00 D SE were included in group B. Patients with pathological myopia, strabismus or heterophoria anomalies were excluded. The PC/ A ratio for both the groups were calculated by measuring the difference between value of accommodative convergence to accommodation ratio (AC/ A) derived from heterophoria and gradient method using a prism bar method. Statistical analysis was performed by analyzing descriptive statistics and the independent sample t-test using SPSS ver. 22.0 software.Results: The average calculated PC/ A ratio was 3.24∆/ D (SD = +0.68/ D) in group B (n=27) and 2.6∆/ D (SD = 0.86/ D) in group A (n=24) (p value <0.05).Conclusion: An evident high AC/ A ratio in group B patients with myopia more than -3.00 D was the predominant cause for high PC/ A ratio in group B patients.

Accommodative and binocular vision dysfunctions in a Portuguese clinical population

BackgroundSeveral studies have suggested that accommodative and non-strabismic binocular dysfunctions are commonly encountered in optometric practice. This study aims to verify whether these findings apply to a Portuguese clinical population. MethodsThis study included consecutive nonpresbyopic subjects that came to two Portuguese optometric clinics over a period of six months. A complete visual exam was conducted and included the measurement of visual acuity (VA), refraction, near point of convergence (NPC), distance and near phoria, near and distance fusional vergences, amplitude of accommodation (AA), monocular accommodative facility (MAF), relative accommodation and lag of accommodation. Results156 subjects with a mean age of 24.9 ± 5.3 years (from 18 to 35 years old) participated in the study. Of all subjects, 32 % presented binocular vision and/or accommodative disorders accompanied or not by refractive errors. Moreover, 21.1 % had accommodative disorders, and 10.9 % had a binocular vision dysfunction. Accommodative insufficiency (11.5 %) was the most prevalent disorder, followed by convergence insufficiency (7.1 %) and accommodative infacility (5. 8 %). ConclusionsClinicians should be aware that about one third of the optometric clinical population could have accommodative and/or non-strabismic binocular disorders. Accommodative insufficiency was the most prevalent dysfunction presented in the studied population, followed by accommodative infacility and convergence insufficiency.

Examination of Near Point of Convergence Scores in High-School Athletes: Implications for Identifying Binocular Vision Dysfunction After Concussion Injury.

To identify normative near point of convergence (NPC) data for healthy high-school-aged athletes (13-19 years old) and determine the percentage of individuals with NPC scores that fall outside the currently accepted clinical cutoff value of 5 cm. Another objective was to determine the relationship between sex, concussion history, and attention deficit disorder/attention deficit hyperactivity disorder (ADD/ADHD) with NPC scores, if any. Case series. High-school sports medicine clinic. Near point of convergence was assessed in 718 high-school student athletes (141 females and 577 males) with an average age of 15.96 ± 1.16 years. None. An accommodation convergence ruler was used to measure NPC. Near point of convergence scores were repeated a total of 3 times and the mean used for all statistical analyses. The NPC scores for all participants averaged 3.58 cm, and the intraclass correlation coefficient for the 3 repeated measurements was 0.956. Approximately 20% of mean NPC scores were above the accepted upper limit of 5 cm. Although a statistically significant effect for sex was identified, the difference between them was considered clinically insignificant. No relationship between NPC and history of concussion or ADD/ADHD was identified. Results indicate that in high-school-aged subjects, approximately 20% of individuals may have NPC values that fall outside the current critical cutoff value and may lead to incorrect diagnosis of ocular dysfunction. In addition, NPC does not seem to be affected by the history of concussion or a diagnosis of ADD/ADHD.

Does coexisting accommodative dysfunction impact clinical convergence measures, symptoms and treatment success for symptomatic convergence insufficiency in children?

To determine whether coexisting accommodative dysfunction in children with symptomatic convergence insufficiency (CI) impacts presenting clinical convergence measures, symptoms and treatment success for CI. Secondary data analyses of monocular accommodative amplitude (AA; push-up method), monocular accommodative facility (AF; ±2.00D lens flippers) and symptoms (CI Symptom Survey [CISS]) in children with symptomatic CI from the Convergence Insufficiency Treatment Trial (N=218) and CITT-Attention and Reading Trial (N=302) were conducted. Decreased AA was defined as more than 2D below the minimum expected amplitude for age (15 - ¼ age); those with AA<5D were excluded. Decreased AF was defined as <6 cycles per minute. Mean near point of convergence (NPC), near positive fusional vergence (PFV) and symptoms (CISS) were compared between those with and without accommodative dysfunction using analysis of variance and independent samples t-testing. Logistic regression was used to compare the effect of baseline accommodative function on treatment success [defined using a composite of improvements in: (1) clinical convergence measures and symptoms (NPC, PFV and CISS scores) or (2) solely convergence measures (NPC and PFV)]. Accommodative dysfunction was common in children with symptomatic CI (55% had decreased AA; 34% had decreased AF). NPC was significantly worse in those with decreased AA (mean difference=6.1cm; p<0.001). Mean baseline CISS scores were slightly worse in children with coexisting accommodative dysfunction (decreased AA or AF) (30.2 points) than those with normal accommodation (26.9 points) (mean difference=3.3 points; p<0.001). Neither baseline accommodative function (p≥0.12 for all) nor interaction of baseline accommodative function and treatment (p≥0.50) were related to treatment success based on the two composite outcomes. A coexisting accommodative dysfunction in children with symptomatic CI is associated with worse NPC, but it does not impact the severity of symptoms in a clinically meaningful way. Concurrent accommodative dysfunction does not impact treatment response for CI.

Refractive changes with post-rotatory nystagmus in healthy individuals.

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. A total of 34 healthy volunteers (mean age ± standard deviation, 20.9 ± 0.6years) 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 30Hz 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. 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. 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.

Non-strabismic binocular vision anomalies among students of a Malaysian private university uses visual display unit

AIM: To determine the status of non-strabismic binocular vision anomalies (NSBVA) among students of a Malaysian private university uses visual display units (VDU). METHODS: A cross-sectional study was conducted among university students who use VDU 3h or more from January 2019 to May 2019. A convenient sampling method was utilized. All subjects had gone through primary eye-examinations to satisfy the inclusion criteria. Those who satisfy the inclusion criteria, further gone through the NSBVA assessment. The descriptive analysis was done to rule out the percentage of NSBVA and Chi-square test of independence was carried out to observe the association of NSBVA with age, gender and hours of VDU usage. RESULTS: A total of 140 students including 88 females (62.9%) and 52 males (37.1%) participated in this study. The mean age of the participants was 22.54±1.48 years and the mean VDU usage hours were 5.76±2.49h. The percentage of NSBVA is 40% among the students those who use VDU. The occurrence of accommodative and vergence anomalies among the VDU users is 17.86% and 22.14% respectively. There was a moderate association between gender and NSBVA (P=0.010). However, there was no significant association observed for age (P=0.334) and hours of VDU usage (P=0.835) with NSBVA. CONCLUSION: NSBVA is 40% among the students of a Malaysian private university uses VDU. Accommodation insufficiency (15%) and convergence insufficiency (10%) is more common among all NSBVA for VDU users.

Normative Data for Nonstrabismic Binocular Vision Parameters in African Schoolchildren.

With reported population differences in parameters of nonstrabismic binocular vision, the present study investigated and reports normative data among a sample of African children. This study aimed to determine expected binocular visual function data among schoolchildren in the Central Region of Ghana. The study used a prospective cross-sectional design and used a multistage cluster sampling approach. Eligible normal participants selected through the administration of Convergence Insufficiency Symptom Survey questionnaire (score <16) and preliminary vision screening underwent comprehensive binocular vision testing. Only data for participants who expressed no difficulty with the specific procedures were analyzed. A total of 1261 normal participants (11 to 17 years [mean, 14.75 ± 1.530 years]) were selected for comprehensive binocular vision testing in the normative data study. The means with ±1 standard deviation for normative data for the nonstrabismic binocular vision parameters include the following: accommodative target near point of convergence (NPC) break (6.10 ± 1.67 cm), NPC recovery (8.17 ± 1.67 cm), fixation light with red-green anaglyph (RG NPC) break (8.51 ± 2.43 cm), RG NPC recovery (10.95 ± 2.60 cm), cover test distance phoria (0.12 ± 0.79 exophoria), cover test near phoria (2.1 ± 2.3 exophoria), modified Thorington test near phoria (1.9 ± 2.5 exophoria), negative relative accommodation (+2.54 ± 0.75 D), positive relative accommodation (-2.58 ± 0.81 D), and the accommodative convergence over accommodation ratio (2.80 ± 1.07:1). Age (in years)-predicted normal linear regression equations for NPC break (5.13 + 0.07 × age), RG NPC break (10.00 - 0.10 × age), RG NPC recovery (12.83 - 0.13 × age), positive relative accommodation (2.05 + 0.04 × age), and the gradient accommodative convergence over accommodation ratio (3.97 - 0.08 × age) serve as a guide. The study provides expected data that optometrists may use with similar aged Black African populations.

High Accommodative Convergence/Accommodation Ratio Consecutive Esotropia Following Surgery for Intermittent Exotropia: Clinical Feature, Diagnosis, and Treatment.

Consecutive esotropia is a common and stereopsis-threatening consequence of surgery for intermittent exotropia. However, too little attention has been paid to the accommodative convergence per accommodation (AC/A) ratio in this condition. We aimed to describe the clinical features of patients who developed consecutive esotropia with a high AC/A following surgery for intermittent exotropia, compared to those with normal AC/A. In this retrospective cohort study, we identified 54 patients with consecutive esotropia who remained esotropic at one month after surgery. Patients were divided into two groups: normal AC/A and high AC/A groups. Clinical features and outcomes were compared between the two groups. Fourteen (25.9%) of the 54 were classified as high AC/A consecutive esotropia. Good preoperative control at near was the only significant preoperative factor associated with the development of high AC/A consecutive esotropia. Bifocal glasses were prescribed for all patients with high AC/A consecutive esotropia, and 11 (78.6%) of them achieved satisfactory alignment at distance and near fixations using bifocals. Patients with high AC/A consecutive esotropia had a significantly more successful alignment (0.9 vs. 13.0 prism diopters, p < 0.001) and better stereopsis (67.9 vs. 670.0 arc seconds, p = 0.04) than the normal AC/A counterparts at the final follow-up. We suggest that high AC/A consecutive esotropia could be successfully managed by wearing bifocals in most cases. A high AC/A ratio in patients with consecutive esotropia may be considered as a clinical marker heralding a better prognosis.

Binocular dynamics of accommodation, convergence, and pupil size in myopes.

The purpose of this work is to study the dynamics of the accommodative response as a function of the subject's refractive error, as a first step in determining whether an anomalous accommodative function could affect emmetropization or trigger myopia progression. A secondary goal was to establish potential relationships between the speed of accommodation and other parameters in the accommodation process. Parameters related to the speed and amplitude of accommodation, convergence, miosis, and change in high-order aberrations were measured during the accommodative process for 2.8 D demand in 18 young healthy subjects (mean age 25.0 ± 4.7 years) with a range of refractive errors between 0 and -7.5 D (spherical equivalent). Measurements were performed in real time (25 Hz) with an open-view binocular Hartmann-Shack (HS) sensor using a GPU-based processing unit. Correlation coefficients were calculated between refractive error and each computed variable. Additionally, the speed of accommodation was correlated with all the other parameters in the study. Correlation coefficients with refractive error had non-zero values for several parameters of the accommodative response but p-values were higher than 0.05 except in two cases: with pupil miosis speed (R = -0.49, p = 0.041) and with lag of accommodation (R = -0.57, p = 0.014). Additionally, correlation values with p-value < 0.05 were found between accommodation speed and convergence duration (R = 0.57, p = 0.014), convergence speed (R = 0.48, p = 0.044), and pupil miosis amplitude (R = 0.47, p = 0.049). We did not find strong evidence of a link between myopia and altered dynamics of the accommodation process. Only miosis speed was found to be correlated to refractive error with p < 0.05, being slower for myopes. On the other hand, increased lag of accommodation tends to be associated to larger refractive errors. Additionally, our data suggests that the faster the accommodation, the faster and longer the convergence and the larger the pupil miosis.

Refractive correction regulated gradient AC/A ratio with low-to-moderate myopia in children and adolescents.

Abnormal accommodative convergence per diopter of accommodative response (AC/A ratio) ratio is an important factor leading to myopia. This study aimed to examine the effect of refractive correction on the gradient of AC/A ratio with low-to-moderate myopia in children and adolescents. Children and adolescents aged 8-18years, with low and moderate myopia, were divided into groups of myopia with no refractive correction and myopic continuous refractive correction of more than half a year. Then, in accordance with the myopia gradient, they were further divided into 0.00 to - 1.50, - 1.75 to - 3.00, - 3.25 to - 4.50, and - 4.75 to - 6.00 groups. Results showed that the AC/A ratio of the myopic group without refractive correction history was significantly higher than that with refractive correction history for more than half a year. The AC/A ratio increased with the deepening of myopia in the group without refractive history of myopia. However, it decreased significantly in the group with refractive history of myopia for more than half a year. Therefore, the AC/A ratio is related to the degree of uncorrected myopia, and it increases with the degree of uncorrected myopia.

Співвідношення акомодативної конвергенції до акомодації і фузіонна здатність у хворих з постійною і періодичною розбіжною косоокістю

Співвідношення акомодативної конвергенції до акомодації і фузіонна здатність у хворих з постійною і періодичною розбіжною косоокістю

Comparison of AC/A Ratio in True and Simulated Divergence Excess Exotropia

Purpose: To compare the accommodation convergence per accommodation ratio (AC/A) in true and simulated divergence excess exotropia.&#x0D; Study Design: Comparative cross sectional study.&#x0D; Place and Duration of Study: Department of ophthalmology, Punjab Rangers teaching hospital, Lahore, from July 2019 to December 2019.&#x0D; Methods: The study included 20 patients each of intermittent exotropia (XT) true and simulated divergence excess exotropia (XT).All the subjects underwent complete orthoptic assessmentthat included AC/A ratio calculation through heterophoria method after monocular occlusion.&#x0D; Results: The Results showed that patients with true divergence excess exotropia have a high AC/A ratio as compared to patients with simulated divergence excess exotropia who have a normal AC/A ratio. 57% patients showed true divergence excess exotropia with high AC/A ratio while 43% had divergence excess with normal AC/A ratio.&#x0D; Conclusion: The response of AC/A was found to be higher in patients with true divergence excess exotropia after monocular occlusion.&#x0D; Key Words: Intermittent exotropia, True simulated divergence excess exotropia, simulated divergence excess exotropia.

The visual impact of augmented reality during an assembly task

Many studies have shown the benefits of augmented reality (AR) to improve manufacturing and control processes in industry. However, the presentation of AR content through optical see-through head-mounted displays may induce unnatural viewing conditions, which consequences on the user’s visual system have not been investigated yet. This study aimed at assessing whether using AR instructions to guide a manual task, i.e., conditions where the user is forced to repeatedly look at and accommodate in different planes to extract information from both real and virtual environments, could potentially impact the visual system of operators. A before/after design study was carried out, asking 26 participants to perform Lego assemblies for 30 min with either paper or AR instructions. The effects of using AR compared to paper instructions were evaluated both on binocular vision, with classical optometric measurements, and on visual fatigue, with the Virtual Reality Symptoms Questionnaire. No clinically significant differences in optometric measurements (far/near visual acuity, stereoacuity, phoria, convergence, fusional amplitude, accommodation amplitude, accommodative convergence) have been found between AR and paper instructions, and only negligible fatigue symptoms have been seen specifically for AR. Results from both objective and subjective measurements suggest that there is no impact of AR on the oculomotor system and that, in this specific case of use, AR can be safely used for production operators.

Factors Affecting Binocular Sensorial Function in Accommodative Esotropia.

Objectives:This study was an assessment of factors related to the development and maintenance of binocular sensory function after successful alignment of accommodative esotropia (AE).Methods:A total of 107 patients aged <12 years with ≥6 months follow-up were included in the study. The variables of age at onset of deviation, duration of deviation before treatment, the amount of uncorrected distance and near deviation, hyperopia, anisometropia, and accommodative convergence to accommodation ratio (AC/A) were evaluated.Results:The study patients had a mean age of 4.9±2.5 years and a mean length of follow-up of 34.3±28 months. Anisometropia was identified in 26.1% of the participants. Anisometropic patients had a greater degree of hyperopia (mean: 5.02±2.07 D) than the patients without (p>0.05). Amblyopia was seen in 25% of the patients with anisometropia, and in 19% of those without (p<0.05). The binocular visual function of the 2 groups was not significantly different (p>0.05). The age at onset of deviation and the duration of deviation did not affect the final outcome (p>0.05 for all). The degree of initial uncorrected distance deviation had a significant effect on the development of amblyopia, fusion, and contoured stereopsis (p<0.05 for all), while the degree of near deviation without correction had a significant effect only on contoured stereopsis.Conclusion:The degree of uncorrected distance and near deviation had a negative impact on binocular vision and stereopsis in AE. The presence of anisometropia, age at onset of deviation, duration of deviation before treatment, high hyperopia, and high AC/A did not pose a significant risk for impaired binocular function.

Spontaneous consecutive sensory esotropia: a case series

We present the first case series of patients with no systemic neurologic disease who experienced a spontaneous conversion from an initial exotropia to a sensory esotropia in the absence of strabismus surgery or chemodenervation. The patients in this series all were exotropic in the first 2years of life, with the strabismic eye having decreased vision due to unilateral ocular pathology. All patients demonstrated spontaneous conversion to esotropia between 4 and 8years of age and thereafter clinically demonstrated a high ratio of accommodative convergence to accommodation. There was no discernible relationship between refractive error and the pattern of spontaneous esotropia. The existence of this rare entity may support delayed surgical correction of strabismus in patients with sensory exotropia.