Journal of Binocular Vision and Ocular Motility最新文献

Purpose: To elucidate the induced effects of horizontal strabismus on the Bielschowsky Head Tilt Test (BHTT).

Design: Prospective clinical study.

Methods: Prospective analysis of BHTT testing in 85 patients with exotropia and 71 patients with esotropia who were examined in a strabismus clinic.

Results: Eighty-four of 85 patients with exotropia (98.82%) showed a positive BHTT with an induced hyperdeviation on the side of the tilt (to both sides in 67% and to one side in 32%). Fifty-seven of 71 patients with esotropia (80.2%) showed a positive BHTT with an induced hypodeviation on the side of the tilt (to both sides in 57.7% and to one side in 22.5%). These induced vertical deviations were greater in patients with larger horizontal deviations and in those with constant rather than intermittent deviations; however, they were not influenced by the presence or absence of associated primary oblique muscle overaction.

Conclusions: Exotropia and esotropia produce hyperdeviations during BHTT testing, with a hyperdeviation on the side of the tilt observed in patients with exotropia, and hypotropia on the side of the tilt observed in patients with esotropia. These diametrical results are not attributable to any preexistent alteration of neurologic output inherent to these two forms of horizontal strabismus or to associated torsion. Rather, they arise directly from the altered anatomical positions of the two eyes, which cause the eyes to approximate their visual axes more closely to the vertical rectus muscles (in exotropia) and the oblique muscles (in esotropia), enabling the vertical actions of specific cyclovertical muscles to predominate in response to altered utricular output generated by the BHTT.

Purpose: 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.

Methods: 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.

Results: 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.

Conclusion: 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.

Post-stroke visual impairment (PSVI) affects more than 60% of the people who have a stroke but visual function is not routinely assessed in most stroke units. Recent high-quality research in this field has produced evidence-based assessment and management practices for PSVI. Orthoptists have integrated into the stroke care team in the United Kingdom (UK) to provide this valuable service. This paper outlines the development and implementation of the first known orthoptic PSVI service in North America. A pilot program was developed between the Ophthalmology, Neurology, and Physical Medicine and Rehabilitation Departments in Saskatoon, Saskatchewan, Canada. A new referral pathway was established to refer stroke patients with PSVI directly to an orthoptist with specialization in PSVI. Clinical findings from the first year of operation are reported. One hundred and seven visual deficits were suspected by the referring service. Visual field deficits were the most commonly reported PSVI. Diplopia was the most commonly reported oculomotor deficit in this cohort, and visual neglect/inattention was the most common visual perceptual deficit reported. Reading issues were the most commonly reported functional issues. Following assessment by an orthoptist, 45 additional visual deficits were identified and addressed. Stroke patients require assessment and treatment for PSVI. Orthoptists are perfectly suited to PSVI assessment and management. There is an opportunity to increase orthoptists' scope of practice in North America to ensure stroke patients receive specialized vision assessment and treatment.

Purpose: To determine the frequency and manifestations of different ocular causes of abnormal head posture (AHP).

Method: 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.

Results: 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°).

Conclusion: 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.

Purpose: 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.

Method: 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.

Results: 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.

Conclusion: 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.

Persistent unilateral or bilateral visual deprivation at any age, particularly in children, can compromise sensory fusion and result in a type of strabismus known as sensory or secondary strabismus. There are several pathologies that can induce visual impairment, such as severe anisometropia, congenital unilateral cataract, corneal opacity, retinal diseases, and optic nerve anomalies. Sensory strabismus may be horizontal or vertical or a combination of them; however, most reports indicate the development of horizontal deviation as sensory strabismus. Regardless of the direction of the sensory strabismus, early diagnosis and management of the underlying pathology are important before strabismus treatment. The primary treatment approach for patients with sensory strabismus is surgery to correct ocular misalignment and straighten the eyes. This can help to improve the patients' symptoms and diminish the negative psychosocial impacts. In this article, we review the underlying etiologies and background pathologies associated with sensory strabismus. In addition, we investigate the determinant factors of the direction of sensory strabismus and its management strategies.

Convergence excess esotropia is a condition characterized by an esotropia which is greater for near fixation than for distance fixation after full hypermetropic correction with a single focus lens. Convergence excess esotropia may be classified according to the AC/A ratio into two subtypes: accommodative type and non-accommodative type. Bifocal glasses are a suitable option for the management of patients with a high AC/A ratio and for the hypoaccommodative type. However, the overall success rate with bifocals is still low even in selected patients. Surgery is often eventually needed for most patients with convergence excess esotropia. Surgical options that do not directly address the variability of the angle of deviation entail medial rectus recession with the target angle based on the distance deviation, the near deviation, an augmented formula based on an intermediate angle, or on a prism adaptation test. Surgical options that directly address the variability of the angle include partial myotomy, medial rectus muscle posterior scleral fixation with or without recession, pulley fixation, slanting recession, Y-splitting, or combined recession-resection of the medial rectus muscle. The review article summarizes the surgical outcome of these strategies and suggests an algorithm for the management of patients with convergence excess esotropia.