To determine the frequency and manifestations of different ocular causes of abnormal head posture (AHP). This prospective, consecutive case series study was performed on 149 patients with ocular AHP at Farabi hospital, Iran, from February 2020 to June 2021. All patients underwent routine ophthalmic examinations. The manifestation of AHP was determined by direct observation from three viewing angles, while the patient read the smallest line on the vision chart that they could see. In front, above, and lateral gazes, observations were performed to find head tilt, head turn, and chin abnormal position, respectively. A picture with habitual AHP was taken from all patients. The amount of head tilt was measured by calculating the angle between the line that connects the lips center to the center of the eyebrows and the vertical line using the Corel Draw X7 computer software. The mean age of 149 patients with ocular AHP [101 (67.8%) males and 48 (32.2%) females] was 16.2 ± 12.2 (range, 2-57) years. The most common ocular sources of AHP were found to be superior oblique palsy (SOP) in 66 (44.3%) patients, 54 (36.2%) cases with Duane's retraction syndrome (DRS), and 12 (8.1%) patients with nystagmus. Other frequent causes of ocular AHP were dissociated vertical deviation (DVD) in 5 (3.4%), A and V pattern strabismus in 3 (2.0%), and 2 cases (1.3%) in each of Brown syndrome, inferior rectus (IR) palsy, and congenital fibrosis of the extraocular muscles (CFEOM). The most common manifestations of AHP in all cases were "pure head turn" (48.3%), followed by "pure head tilt" (24.8%), "simultaneous head tilt and head turn" (20.8%), and "chin up" (6.0%). The mean head tilt among all patients with head tilt was 10.4° ± 8.9° (range, 5.0°-31.7°). The most frequent ocular sources of AHP were SOP, DRS, and nystagmus, followed by DVD, A and V pattern strabismus, IR palsy, CFEOM, and Brown syndrome. In addition, pure head turn and pure head tilt were the most common manifestations of ocular AHP but were not always seen in the same direction or combination as previously reported with these etiologies.
To review the diagnostic protocols of non-strabismic binocular vision anomalies. We carried out a literature search on published articles of non-strabismic accommodative and vergence anomalies in different international optometry and ophthalmology journals found in the Pubmed, ResearchGate, Google Scholar, and MEDLINE databases. The diagnostic criteria and normative data from the nine articles selected show discrepancies and variability in methodologies and techniques in the overall assessment of Non-Strabismic Binocular Vision Anomalies (NSBVA). Near point of convergence measurement is the most common assessment, whereas the vergence facility is the least commonly used assessment in terms of evaluating convergence insufficiency. Near point of convergence > 10 cm alone is the most sensitive sign to detect convergence insufficiency in a community set-up but high positive relative accommodation (>3.50D) is the most sensitive sign to diagnose accommodative excess. On the other hand, monocular accommodative facility < 7 CPM has the highest sensitivity to confirm the diagnosis of accommodative infacility. This review also indicates that the more clinical signs that are included in a set of diagnostic criteria, the lower the prevalence rate for that diagnosis. There is no standardized and diagnostically validated protocol for the assessment of NSBVAs. Variable cutoff values obtained using different methods and the selection of diagnostic criteria by various researchers have led to discrepancies that highlight the need for diagnostic validity of available protocols (combination of tests) for each anomaly. Clinical signs such as positive relative accommodation (PRA) for accommodative excess, near point of convergence (NPC) for convergence insufficiency and monocular accommodative facility (MAF) for accommodative infacility were found to be useful diagnostic signs of these anomalies. Studies should be carried out for accommodative and vergence dysfunctions using proper designs and methods to validate diagnostic criteria for all age groups. Standardization of assessment protocol and cutoff criteria will also aid in calculating prevalence for non-strabismic binocular vision anomalies.
To study the clinical profile and surgical outcomes of patients with bilateral Duane syndrome with exotropia. The records of all consecutive patients diagnosed with bilateral Duane syndrome with exotropia in primary gaze (2010-2024) were reviewed. Patient demography, age at presentation, and type of Duane syndrome were studied in the clinical profile. The pre-operative and post-operative details of angle of deviation, abnormal head posture, horizontal ocular ductions, grade of globe retraction, and overshoot were evaluated for the surgical outcomes. Forty-five patients (male, 51%) were diagnosed with bilateral Duane syndrome with exotropia, of which 38% underwent surgical correction. The mean age at presentation was 18.06 ± 12.08 years. Of the total, 37% were emmetropic and 29% amblyopic. Bilateral type 3 Duane syndrome (49%) was the most common presentation. The mean pre-operative deviation for distance and near was 29.84 ± 17.73Δ and 32.49 ± 18.44Δ, respectively. The mean change in angle of deviation post-operatively for distance and near was 23 ± 5Δ and 26 ± 5Δ, respectively. The average angle of deviation at the final follow-up for distance was 8 ± 12Δ and near 12 ± 12Δ. Surgical success for primary position deviation, abnormal head posture, globe retractions, and overshoots was achieved in 59%, 86%, 57%, and 50% patients, respectively. Bilateral type 3 is the most common bilateral Duane syndrome with exotropia. Individualized surgical management (algorithm) ensures optimal alignment and head posture correction.
Prematurely born children are at risk of numerous complications that affect the visual system. Retinopathy of prematurity (ROP) and cerebral visual impairment (CVI) are among two major causes of childhood blindness and visual impairment in industrialized nations, and large countries with emerging economies are seeing increasing childhood blindness from ROP alone, adding to the burden of disease worldwide. The purpose of this paper is to review the long-term impacts of prematurity, ROP and CVI on vision in children who were born preterm. The topics in this review of the literature include the burden of vision loss in prematurely born children world-wide, a description of ROP and CVI, effects on visual acuity, refractive errors, strabismus and binocularity, visual fields and contrast sensitivity, and risk factors for visual complications. Children who are most at risk of visual complications are those with the smallest gestational age at birth and birth weight in general. Although ROP severity and the presence of neurological impairments including CVI play a large role in the development of poor visual outcomes, premature birth alone without CVI or severe ROP increases the risk of future visual complications. Awareness of signs and symptoms of CVI are important in the management of affected children. Children born preterm are at increased risk of reduced visual acuity, refractive errors, strabismus and amblyopia, complications of ROP, CVI, visual field abnormalities and reduced contrast sensitivity. Awareness of risk factors warranting close monitoring and signs and symptoms of CVI are critical to optimize the visual outcomes and overall development.
Uncorrected refractive error is a key cause of childhood visual impairment in the United States. As pediatric vision issues are often asymptomatic, vision screenings are essential to identify children's eye problems. Despite the importance of vision for children's health, well-being, and academic achievement, challenges remain in ensuring that children have equitable access to vision screenings and follow-up eye care. Children of racial and ethnic minorities experience a greater burden of myopia, while longstanding disparities in eye care access have been observed across both race and socioeconomic status. Collaborations with schools and community organizations may represent effective strategies to increase children's access to eye care in underserved communities. By providing services directly at schools, school-based vision programs have demonstrated success in addressing children's refractive error and need for eyeglasses. Future work for community-based programs may engage schools, eye care professionals, and other community stakeholders in collaborations to address children's unmet eye care needs.
The psychometric properties of the Convergence Insufficiency Symptom Survey (CISS) have been previously determined across the younger adult population. This study investigated the psychometric properties of the CISS in presbyopic adults via classical and Rasch analysis. A total of 100 presbyopic individuals (40-60 years) were selected with far and near acuity of 20/20 with their habitual spectacles; 50 had convergence insufficiency and 50 had normal binocular vision. Refraction, cover test, near point of convergence, and positive fusional ranges were examined. The Persian translated CISS was administered twice, once in the first session and 7 to 14 days later. Classical and Rasch analyses were conducted. The mean ages and gender ratios in the CI group and normal group were 49.70 ± 5.96 and 49.82 ± 5.64 years with a 50% female distribution among individuals. The mean CISS scores for presbyopes with CI and normal groups were 19.24 ± 5.33 and 13.26 ± 3.53 respectively (p < 0.001). Effective discrimination was achieved with a score greater than 15, yielding a sensitivity of 72%, a specificity of 69%, and an Area Under the Curve (AUC) of 0.813. For internal consistency, Cronbach's α coefficient was 0.82. For test-retest reliability in CISS scores, ICC was 0.91 (confidence interval 0.88-0.93) with the 95% limits of agreement in CI group being - 3.91 to 2.59. The Rasch analysis demonstrated a satisfactory model fit, as all items had infit and outfit mean square values ranging between 0.6 and 1.4. The measurement precision was good, with a person separation value of 2.30. Additionally, the first contrast eigenvalue of 2.34 and a raw variance of less than 50% indicated multidimensionality. The CI group reported headaches (item 3) more frequently than the normal binocular vision group did. However, eye discomfort scores (item 10) were similar for both groups. The CISS is a valid and reliable tool for assessing the symptoms in presbyopic adults. However, due to this survey's multidimensionality, we recommend additional objective examinations in presbyopic adults with CI.
Cataracts are the leading cause of reversible blindness in the world. Their prevalence is expected to dramatically increase with the anticipated global population growth by 2050, consequently increasing the need for cataract surgery. As cataract surgery evolves, novel types of intraocular lenses (IOLs) are also emerging. Extended depth of focus (EDOF) lenses are a recently introduced lens technology that was approved for commercial use in 2016. The lens optics create a focal zone with an overlap for near and far images, enabling an enhanced depth of focus for intermediate vision with little impact on distance vision. Reports of sensorimotor decompensation, such as ocular misalignment and diplopia, following cataract surgery have been described in the literature, particularly in patients with a history of strabismus or diplopia. However, there is very limited literature to determine if newer multifocal IOLs, such as EDOF lenses, carry the same risk of sensorimotor decompensation. The purpose of this report is to describe two cases with sensorimotor disturbances after uncomplicated bilateral EDOF IOL implantation, the first being decompensation of stereopsis in a patient with previously well-controlled accommodative esotropia, and the second involving the development of vertical diplopia post-operatively.
Homonymous and heteronymous hemianopias associated with strabismus are a therapeutic challenge because surgery may result in diplopia, decrease the visual field (VF), and/or lead to recurrence of the deviation. We present four cases: two homonymous hemianopias and two heteronymous hemianopias. Of the four patients, three had exotropia and one had esotropia. The origin of hemianopias was neoplastic in two cases and traumatic in two cases. Strabismus surgery was performed in three cases, but only one case had a good result; recurrence of the deviation and diplopia occurred in the other two cases. In conclusion, exotropia may develop as a compensatory mechanism in a patient with congenital or early-onset homonymous hemianopia and realigning the eyes could reduce the binocular VF and cause diplopia. In heteronymous hemianopias, there is little risk of the surgery causing diplopia, but the strabismus is unstable because of the absence of binocular vision and vergence reflexes if VF loss includes the macula. Further, strabismus, in association with hemianopia, may be caused by coexistent cranial nerve and/or gaze palsy. The prognosis, objective, and results of the strabismus operation should be clearly discussed with the patients or their guardians before it is performed if hemianopias are present.
Convergence insufficiency (CI) is a common condition that can impair visual performance and comfort during close visual work. This observational study evaluated the effectiveness of interventions on clinical outcomes and health-related quality-of-life using the Adult Strabismus-20 (AS20) questionnaire in patients with CI. Data was extracted from a database collected at first consultation from 2015 to 2022. Demographics, interventions and outcomes of 75 patients with CI (mean age 47.2 ± 24.7 years) were analysed. Orthoptic exercises were prescribed to 58% of patients, 28% received prisms and 9% received no treatment. At the latest follow-up review, 24% were recommended to continue exercises, 24% had prisms, 1 underwent bimedial resection and 1 had treatment with Botulinum Toxin A (BTXA). The median follow-up was 5.0 (0-55) months, 100% were discharged with 25% following failure-to-attend and 11% died. At the latest follow-up, the attendance failure rate was higher for exercises (36%) than for prisms (10%). Both near-prism cover test and near-point of convergence improved from a median of 12 (95% CI 10-14) prism dioptres (PD) to 8.5 (95% CI 6-12) PD, and 17.5 (95%CI 15-20) cm to 10.0 (95%CI 8.3-12.0) cm respectively (p < 0.05). Near-prism fusion range also improved from 10(95%CI 8-14) PD to 16(95% CI 12-20) PD (p < 0.05). The median AS20 score at presentation were 100/100 (30-100) and 47.5/100 (0-100), and post-intervention were 100/100 (75-100) and 70/100 (12.5-97.5) for psychosocial and functional components, respectively. This cohort offers valuable insights into the real-life clinical management of CI in a tertiary adult strabismus centre. However, the study also found that long-term compliance with treatment is intrinsically challenging, emphasising the importance of disease education.
There is sparse literature on radiological findings in cases of monocular elevation deficit (MED). We conducted this study to report magnetic resonance imaging (MRI) characteristics of extra-ocular muscles and oculomotor nerves in patients with congenital MED and to investigate its patho-mechanisms. We included patients with congenital MED without prior strabismus surgery. The cross-sectional area (CSA) of the extra-ocular muscles in quasi-sagittal and quasi-coronal scans was measured manually on 2-mm-thick T2-weighted MRI images using Osirix MD software. Oculomotor nerves were imaged with balanced steady state free precession (bFFE) sequence. Clinical findings of Bell's phenomenon and forced duction test (FDT) for inferior rectus (IR) muscle were recorded. Eleven patients were included. The median CSA of superior rectus (SR) muscle at mid-orbit section was significantly lesser in the affected eye (8.83 mm2, Inter-quartile range (IQR): 5.39-11.36 mm2) than in the normal eye (13.63 mm2, IQR: 10.99-16.92 mm2), p = .02. From 11 patients, 10 had a thinner SR muscle on the affected side. Bell's phenomenon was intact in six patients. Forced duction test was positive for IR muscle in five cases. Oculomotor nerve was thinner on the affected side in two patients. Majority patients with congenital MED have a hypotrophic SR muscle, due to dysinnervation or primary muscle pathology. Bell's phenomenon may or may not be present in these conditions, and its presence does not warrant a supra-nuclear cause.
To evaluate the effect of unilateral medial rectus (MR) recession for the correction of 20 to 30 ∆ of esotropia. Pediatric patients with esotropia (ET) with a surgical target of 20 to 30 prism diopters (∆) were included in a prospective study to determine the effect of unilateral MR recession. The surgical target angle was calculated as the average of the distant angle with glasses and near without glasses, or the average of distant and near angles without glasses (if non-significant refractive error), or the average of near angles with and without glasses (if ET was measured using the modified Krimsky test). The study endpoint was the last follow-up visit, conducted at least 3 months postoperatively. A successful motor outcome was defined as orthotropia or a horizontal tropia of 10∆ or less at distance and near. The study included 21 patients, 1 to 12 years of age. Patients were followed up for 3 to 43 (mean+/-SD 12.5+/-10.6) months. A successful outcome was achieved in 85.7%, with no correlation to the surgical target angle or the amount of recession (p > .05). The 14.3% failure rate was attributed to undercorrections. Persistent lateral incomitance was observed in 10.5% of cases and was not correlated with the surgical target angle or the amount of recession (p > .05). Persistent limited ductions were mild (-1). This prospective study of pediatric patients showed that unilateral MR recession is a reasonable surgical approach for treating esotropia of 20-30 ∆, with small rates of undercorrection and duction limitation, and no overcorrection.
Accommodative spasm (AS) is an involuntary condition characterized by excessive contraction of the ciliary muscle, leading to exaggerated accommodative response and fluctuating refractive error. The reported prevalence of accommodative spasm ranges from 2.6% in an Indian clinic cohort to 37.19% in Chinese school children. Since the COVID-19 pandemic, accommodative spasm has been reported in 20% of symptomatic patients associated with increased near work and digital screen exposure. It often presents with headache, photophobia, blurred distance vision, and eye strain. This case report describes bilateral accommodative spasm in a 14-year-old female who presented with blurred distance vision in left eye and headaches. Best-corrected visual acuity was 20/20 in the right eye and 20/400 in the left eye; near acuity was N6 in both eyes. Objective refraction using an open-field autorefractor (WAM-5500) showed fluctuating myopia. Retinoscopy revealed a vacillating reflex, and a lead of accommodation on dynamic retinoscopy suggesting accommodative instability, which was further confirmed by excessive accommodative responses measured using open-field autorefractor. Baseline ocular biometry revealed axial length within the normal range, increased lens thickness, and reduced anterior chamber depth. The patient was treated with 1% atropine sulfate eye ointment, administered twice daily for three days. Cycloplegic refraction on day four showed resolution of the spasm with a stable retinoscopic reflex. After a 21-day atropine washout, repeat retinoscopy confirmed the absence of accommodative instability. Post-mydriatic ocular biometry showed no change in axial length but significant improvements in lens thickness and anterior chamber depth. This case highlights the potential role of objective ocular biometry as an adjunctive tool in accommodative spasm, providing additional structural insights that may aid clinical diagnosis and treatment monitoring.
Unilateral or asymmetric astigmatism is considered a principal refractive error leading to amblyopia and regular eye examinations should be carried out during childhood to prevent visual impairment. The aim of this study was to evaluate the prevalence of astigmatism and spectacle wear among Polish schoolchildren. A cross sectional study was carried out in children aged 6 to 14 years old from 50 schools in Poland. The presence of astigmatism was assessed by non-cycloplegic autorefraction, and defined as a cylinder equal or greater than 0.75 D. Children were classified as living in urban or rural areas according to the school location. Spectacle wear was defined as having spectacles at school. The study included 1041 children and 52.3% were girls (n = 544). The mean age was 8.62 ± 2.04 years. The prevalence of astigmatism was 7.3% (95% confidence interval [CI]: 5.8-9.1%). Only 21.7% of children with astigmatism wore spectacles at school. Astigmatism was diagnosed in 8.2% of boys (95% CI: 6.0-11.0%) and 6.4% of girls (95% CI: 4.5-8.8%; p = .13); cylindrical anisometropia was present in 19/76 (25.0%) of children with astigmatism (95% CI: 15.8%-36.3%). Against-the-rule astigmatism was the most common; it was observed in 48.7% of children with astigmatism, followed by with-the-rule astigmatism (44.7%) and oblique astigmatism (6.6%). The prevalence of astigmatism was not linearly correlated with age (r = 0.24; p = .53). Gender, age and place of living were not significantly associated with the presence of astigmatism. This study reports a low prevalence of astigmatism in Polish school children. However, the majority of children with astigmatism were uncorrected. Further longitudinal studies are warranted.
To investigate changes in eye alignment before and after ICL implantation in patients with myopia having corrected distance visual acuity (CDVA) of ≥0.0 logMAR. The medical records of 1012 patients without eye movement limitation who underwent bilateral ICL implantation were retrospectively reviewed a at the Eye Center of Sanno Hospital in Japan. Preoperatively, of 1012 patients, 30 (3.0%), 211 (20.8%), 771 (76.2%), and 126 (12.5%) demonstrated constant strabismus, intermittent strabismus, phoria, and binocular diplopia, respectively. Regarding horizontal strabismus without a vertical component, of 30 patients, 9 (30.0%) demonstrated exotropia and 2 (6.7%) exhibited esotropia. Vertical strabismus without a horizontal component was not observed. A combination of horizontal and vertical strabismus was observed in 19 (63.3%) patients. The rate of eye alignment classification agreement preoperatively and postoperatively was 98.7%, including 100%, 93.8%, and 100% in the constant strabismus, intermittent strabismus, and phoria groups, respectively. Of 1012 patients, 1.3% converted from intermittent strabismus to phoria (6.2% in the intermittent strabismus group). Uncomplicated ICL implantation under topical anesthesia was not associated with eye alignment in 98.7% of patients with myopia, and 0% transitioned to constant strabismus after ICL implantation.
To characterize the clinical profile, surgical outcomes, and prognostic factors of acute acquired V-pattern esotropia (AAVE), a rare, understudied subtype of strabismus, and compare its features to classic V-pattern esotropia (VE). In this retrospective cohort study, 37 AAVE and 39 VE patients underwent standardized surgical correction. Outcomes included alignment, stereoacuity, and refractive status. Compared to VE, AAVE patients were significantly older at onset (8.5 vs. 3.0 years, p < .0001), exhibited milder hyperopia (+0.68D vs. +2.90D, p < .0001), and presented with larger preoperative esodeviations (44.1 vs. 36.8 PD, p = .0109). After 1-year follow-up, stereoacuity recovery was superior in AAVE patients (80.8% achieving good stereoacuity vs. 37.9% in VE; p = .0127), though surgical success rates did not differ significantly (73.0% vs. 64.1%, p = .4057). AAVE represents a distinct diagnostic entity marked by acute onset, older age, and superior postoperative sensory recovery. Its unique refractive profile and association with modern near-work stressors raises consideration of modern visual stressors in pattern strabismus, supporting consideration of early surgical intervention to maximize binocular potential. These findings suggest that AAVE represents an important subtype in pediatric ophthalmology, supporting the need for updated clinical guidelines.
Myopia has been included as one of the five serious ocular conditions leading to blindness. Prevalence of myopia (between -0.50D and -5.75D) is only of concern because it tends to progress. The incidence of high myopia and pathologic myopia are directly correlated to the prevalence of myopia. Recent studies have concluded that the mean age of onset of myopia is decreasing, the progression interval and the rate of progression is increasing, and the prevalence of high myopia is increasing in older age groups. These epidemiological changes have been associated with global urbanization. High myopia and older age are two primary risk factors for potentially blinding pathologic myopia. The prevalence of myopia by the year 2050 has been estimated to be 50%. Twenty-percent of those myopic individuals are projected to have high myopia. However, these calculations were made in 2016, prior to the COVID-19 quarantine and the increase in extreme climate events. Recent global events have resulted in permanent shifts in lifestyle that may accelerate the development and progression of myopia.
Unilateral congenital cataracts present multiple barriers in the development of vision and stereoacuity despite the improved visual optics that early surgery, contact lenses and intraocular lenses (IOL) have provided. With better understanding of the latent period (the timeframe in which the abnormal event has no long-term effect on visual development in the deprived eye) and the critical periods (the age range during which developing brains can be altered in a profound and permanent way by abnormal experience) for stereoacuity and amblyopia we can focus our treatment methods to not only improve vision but also develop binocularity. Fifty years ago, it was believed that it was almost impossible for an eye with a unilateral congenital cataract to achieve good visual acuity. Twenty-five years ago, we believed that it was almost impossible for an eye with a unilateral cataract to achieve stereoacuity. It is time to expand our belief that the best that we can do with the eye in unilateral congenital cataract is to create a spare.
Introduction: This study aims to describe an objective and simple method to estimate the alignment of eyes under general anesthesia (GA) in strabismus subjects, which may vary from the angle measured preoperatively.Materials and Methods: Through the operating microscope, pictures of the eye position of 94 subjects with horizontal strabismus were captured under GA. A curved caliper was placed parallel to the horizontal meridian, and the distance between the center of cornea and the corneal reflex spot of the microscope was measured. The eye position was estimated with a quantified Hirschberg method for each eye, and the values were added to reflect the global binocular angle of deviation. To validate this method, four strabismus surgeons blindly evaluated the strabismus angle based on these pictures, and the results were compared. Agreement between the four measurements was estimated using the ICC (Intraclass Correlation Coefficient) index.Results: ICC coefficients and their 95% confidence interval were 0.93 (0.88-0.95) for the overall angle, 0.91 (0.89-0.94) for the right eye and 0.86 (0.77-0.91) for the left eye, indicating good to excellent reliability of these measurements.Conclusion: Evaluating the evolution of the strabismus under GA may be of clinical interest and have potential therapeutical consequences. The described technique is fast, convenient, and reliable and provides a tool to encourage surgeons to take into account this parameter of strabismus.
Intermittent exotropia is a common form of pediatric strabismus characterized by intermittent misalignment of the eyes. This study investigated the clinical effectiveness of alternating occlusion therapy as a non-surgical alternative for children aged 3-10 with intermittent exotropia. A comprehensive review of recent research, including randomized controlled trials and case series, was conducted. These studies utilized standardized control scores to assess the impact of alternating occlusion therapy on both distance and near control of alignment. The findings indicated a significant improvement in exotropia control, particularly at distance fixation, among children undergoing alternating occlusion therapy. While some variability in outcomes exists, all articles demonstrate positive responses to this noninvasive approach. Notably, the patients with poor initial control tended to benefit the most. The potential advantages of alternating occlusion therapy are its cost-effectiveness and noninvasive nature. However, it is essential to manage patient and parental expectations and address potential drawbacks, including social stress, irritation associated with occlusion therapy and the possibility that strabismus surgery may still be needed in the future because of decompensation. Alternating occlusion therapy is a promising option to improve exotropia control in children with intermittent exotropia. It offers a viable non-surgical strategy to delay or potentially avoid strabismus surgery, although approximately 45% of the patients might eventually still require strabismus surgery. Healthcare providers should carefully weigh the benefits and limitations of this intervention to make informed decisions through shared decision-making with the patients and their families. This review offers diverse insights into the clinical management of intermittent exotropia and provides an evidence-based alternative to surgical interventions.
Our study aims to investigate the effect of decreasing distance from the patient to the fixation target on the measurement of strabismus with a known distance-near disparity. Strabismus measurements were taken by one pediatric ophthalmologist at our standard distance of 18 feet and compared to those taken at 16, 14, 12, and 10 feet from the fixation target. A clinically meaningful difference was defined as >2.5 prism diopters (PD), since a difference of that magnitude may alter surgical planning. Thirty-nine subjects, including 22 exotropes and 17 esotropes, were included in this study. Mean prism diopter difference (PDD) in the exotrope group at lengths of 16, 14, 12, and 10 feet compared to 18 feet were 1.3 (SD 1.9, range 0-6), 1.3 (SD 2.2, range 0-8), 1.7 (SD 3.2, range 0-14), and 2.8 (SD 4.4, range 0-14), respectively. Among esotropes, the mean PDD at the same distances were 1.1 (SD 1.9, range 0-7), 2.1 (SD 2.6, range 0-7), 3.9 (SD 4.9, range 0-19), and 4.3 (SD 5.1, range 0-19). The percentages of exotropes with a PDD of >2.5 at 16, 14, 12, and 10 feet compared to 18 feet were 13.6% (n = 3), 13.6% (n = 3), 18.2% (n = 4), and 27.3% (n = 6), respectively. In the esotrope group, 11.8% (n = 2), 35.3% (n = 6), 47.1% (n = 8), and 47.1% (n = 8) had a PDD of >2.5 at the same distances, respectively. This pilot study is the first to investigate the change in measured angle of strabismus at various non-mirrored distances from the patient to the fixation target. Our methodology defines a framework that could be used in a higher-powered study to further our understanding of the effect of room length on strabismus evaluation.