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At least 685 records · Page 38Linked to original sources
PubMed2004

Can misalignments in typical infants be used as a model for infantile esotropia?

PURPOSE: To investigate the nature of early ocular misalignments in human infants to determine whether they can provide insight into the etiology of esotropia and, in particular, to examine the correlates of misalignments. METHODS: A remote haploscopic photorefraction system was used to measure accommodation and vergence in 146 infants between 0 and 12 months of age. Infants underwent photorefraction immediately after watching a target moving between two of five viewing distances (25, 33, 50, 100, and 200 cm). In some instances, infants were tested in two conditions: both eyes open and one eye occluded. The resultant data were screened for instances of large misalignments. Data were assessed to determine whether accommodative, retinal disparity, or other cues were associated with the occurrence of misalignments. RESULTS: The results showed that there was no correlation between accommodative behavior and misalignments. Infants were more likely to show misalignments when retinal disparity cues were removed through occlusion. They were also more likely to show misalignments immediately after the target moved from a near to a far position in comparison to far-to-near target movement. DISCUSSION: The data suggest that the prevalence of misalignments in infants of 2 to 3 months of age is decreased by the addition of retinal disparity cues to the stimulus. In addition, target movement away from the infant increases the prevalence of misalignments. These data are compatible with the notion that misalignment are caused by poor sensitivity to targets moving away from the infant and support the theory that some forms of strabismus could be related to failure in a system that is sensitive to the direction of motion.

Accommodation, Ocular↗
PubMed1975

Ocular findings in patients with arteriovenous malformations of the head and neck.

The hospital charts of 71 patients with congenital arteriovenous malformation of the head or neck, excluding carotid-cavernous sinus fistulas, yiedled 25 patients, referred to the ophthalmology service for examination. Of these, 22 patients had ocular findings; additionally, 12 patients with visual complaints or ocular findings were not referred for ocular examination. Forty-seven percent of all patients had ocular signs and symptoms including subjective visual complaints, visual field loss, ophthalmic artery pressure changes, nystagmus and motility findings, orbital and ocular vascular abnormalities, and fundus changes including optic atrophy, hypoxic retinopathy, and papilledema. Every patient with known or suspected arteriovenous malformation of the head or neck should have a thorough ocular examination. The findings can generally be correlated with the anatomic location and size of the lesion.

Accommodation, Ocular↗
PubMed1985

Convergent strabismic amblyopia in cats.

Experiments were carried out to determine the effects of different types of experimental strabismus on the acuities of retinal ganglion cells. Six kittens were raised from twenty-one days of age with an esotropia surgically induced by myectomy of the lateral rectus muscle and a large portion of the superior oblique muscle. The results are compared with those, previously reported, from five other cats also made esotropic, but by tenotomy of the lateral rectus. All animals tested behaviourally were amblyopic in the strabismic eye. For square wave gratings, the visual acuities were 1.0 to 2.5 cyc/deg through the strabismic eye compared with 6.0 to 7.5 cyc/deg through the non-deviating eye. The cut-off spatial frequencies were determined for 132 brisk sustained cells from five of the myectomized strabismic cats. There was a loss of approximately 20% in cut-off spatial frequency when compared with both normal and tenotomized cats. A correlate of the physiologically observed difference between the tenotomized cats and the myectomized cats was also found in the morphology of cells in the lateral geniculate nucleus. The tenotomized cats showed no evidence of cell shrinkage in laminae receiving a projection from the amblyopic eye whereas in the myectomized cats large differences were observed in cell cross-sectional areas between laminae receiving input from the amblyopic eye and those receiving input from the non-deviating eye. Together, these findings indicate that the presence of a neural deficit in the retina of strabismic cats is associated with the actual removal of extra-ocular muscle and probably has little to do with the optical quality of images arriving at the retina.

Accommodation, Ocular↗
PubMed2000

Ocular components before and after acquired, nonaccommodative esotropia.

BACKGROUND: Acquired nonaccommodative esotropia describes the sudden onset of a constant, comitant strabismus of idiopathic origin in children >6 months of age. CASE REPORT: We present a case of acquired nonaccommodative esotropia at 20 months of age in a subject participating in the Berkeley Infant Biometry Study, a longitudinal study of emmetropization and ocular component development in infants between 3 months and 3 years of age. Ocular components for this child were normal before the onset of strabismus (within 2 SD's of the mean for orthotropic study participants) for refractive error, corneal power, lens radii, lens power, and ocular axial dimensions. Refractive error postsurgically was significantly more hyperopic and crystalline lens power lower than average at +2.38 D and 37.2 D, respectively. CONCLUSIONS: The lack of abnormal ocular parameters is consistent with the idiopathic etiology of acute onset esotropia. This case suggests that ocular component values may not be useful for assessing the risk of acquired nonaccommodative esotropia.

Accommodation, Ocular↗
PubMed1995

The role of the ocular lens in the regulation of intraocular pressure.

The relationship between lenticular colloid osmotic (oncotic) pressure and intraocular pressure is discussed, with particular reference to a postulated buffering reservoir action of the lens in protecting against acute changes in intraocular pressure. A hypothesis is developed regarding acute lenticular volume changes in those species manifesting change in lens shape during accommodation. The unusually high colloid osmotic pressure of fish lenses is discussed and related to their unique means of accommodation and their susceptibility to cataract formation.

Accommodation, Ocular↗
PubMed1975

Strabismus and pseudostrabismus with retrolental fibroplasia.

Three patients with temporal displacement of the macular secondary to retrolental fibroplasia had true strabismus in associations with amblyopia and pseudostrabismus related to a large, positive angle kappa. In one case, a headturn associated with the neutral point of nystagmus was also a presenting problem. Ocular deviation was measured by the light reflex test and the prism cover test, with particular attention paid to adequate cosmetic alignment. Large amounts of prism placed before the fixating eye resulted in loss of visual acuity, while eyes placed in a parallel position by surgical means may not appear to be straight. Thus, surgery can result in parallel ocular alignment while prismatic therapy may be required to center the pupillary light reflex and to provide satisfactory cosmetic appearance.

Accommodation, Ocular↗
PubMed1977

Ocular accomodative changes in humans induced by positional changes with respect to gravity.

Ocular accomodation was measured in human subjects while they were rotated at 1 degree/sec about their naso-occipital axes. Sixteen normal subjects were tested with 45 complete and 27 partial revolutions. Naso-occipital rotations ipsilateral to the eye being observed caused accommodative, lens-thickening changes. This effect begin at about 14 degrees from head upright position, tended to reach a maximum by 45 degrees and usually stayed at this level until about 90 degrees. The values tended to return to control level by 180 degrees. With naso-occipital roll in the direction opposite to the eye being observed, there was little change until about 135 degrees at which point further roll was typically clear accomodation. This continued to a maximum at about 270 degrees rotation, and at about 350 degrees returned to control values. Arguments are presented relating this response to the utricles, which are approximately parallel to earth horizontal. The threshold of this response, between 3.7 and 77 cm/sec2, is similar to the threshold of linear acceleration when measured by other means.

Accommodation, Ocular↗
PubMed1985

Diplopia.

Diplopia may be a presenting symptom of a wide variety of ocular and neurological conditions. Careful questioning and examination will reveal the cause in many cases and may save the patient much unnecessary and expensive investigation.

Accommodation, Ocular↗
PubMed1995

Effects of exercise on aspects of visual function.

Strenuous exercise has been reported to affect various aspects of visual and ocular function. In the first of two experiments, the effects of cycling, jogging and stair running on a range of visual functions were examined. None of these forms of exercise was found to have any significant effect on visual acuity, refractive error, dark focus, amplitude of accommodation or pupil size. Contrast sensitivity (CS), measured by an ascending method of limits (AML), was found to improve significantly after cycling and jogging but not after stair running. To investigate if the apparent improvement in CS was related to a change in 'sensitivity' or a change in decision criteria, CS was re-measured before and after cycling using both the AML and a 'criterion-free' method of constant stimuli (MOCS) procedure. Results obtained using the AML, confirmed the findings of the first experiment. However, results obtained using the MOCS procedure showed no significant change with exercise. This suggests that the improvement in CS found using the AML was due to a shift in subjects' decision criteria rather than a physiological change in 'sensitivity'. It is argued that this change in decision criteria may be related to the positive mood changes which have been found to occur after exercise. This study demonstrates the importance of differentiating between changes in 'sensitivity' and changes in decision criteria especially where mood or motivation (and hence decision criteria) may be confounded with the independent variable. This is particularly important when evaluating the effects of exercise on visual function or evaluating the efficacy of vision training.

Accommodation, Ocular↗
PubMed1984

The cynomolgus monkey as a model for orbital research. III. Effects on ocular physiology of lateral orbitotomy and isolation of the ciliary ganglion.

Five cynomolgus monkeys underwent unilateral lateral orbitotomy and isolation but not removal of the ciliary ganglion. Orbitotomized eyes were compared with untouched contralateral eyes with respect to intraocular pressure, aqueous humor formation rate, pupillary diameter and light reflex, corneal reflex, entry of intravenously administered fluorescein into the anterior chamber, anterior chamber volume, pharmacologically (pilocarpine, carbachol, echothiophate) induced accommodation, electroretinogram (ERG), visually evoked cortical response (VER), and clinical biomicroscopy, ophthalmoscopy, and fluorescein fundus angiography. Orbitotomized eyes accommodated significantly less than contralateral normal eyes in response to topical echothiophate one to two weeks after surgery. This difference was no longer present 15 to 20 weeks after orbitotomy. The implicit time on the light adapted ERG in the orbitotomized eyes was slightly but significantly shorter than in the normal eyes two to six weeks after orbitotomy; all the other ERG and VER parameters were the same in both eyes. Long-term ERG data were not obtained. There were no significant differences between normal and orbitotomized eyes with respect to any of the other parameters.

Accommodation, Ocular↗
PubMed1989

Calculation of crystalline lens radii without resort to phakometry.

A computing scheme was developed in 1988 to determine the equivalent powers of the eye and its crystalline lens without resort to phakometry. An adaptation to this scheme is described which allows calculation of the crystalline lens radii using an assumed average value for Q. The values obtained for lens radii using this method compare well with phakometric measurements made on 36 eyes (ocular refraction range -9.37 D to + 3.14 D) which suggests that the variations in Q for a large proportion of the population are small.

Accommodation, Ocular↗
PubMed2026

Repeated low-level red-light therapy for improving asthenopic symptoms and accommodation in presbyopia.

BACKGROUND: To assess the short-term effectiveness of repeated low-level red light (RLRL) therapy in relieving asthenopia and enhancing accommodation in presbyopia. METHODS: This randomized, parallel-group, double-masked clinical trial enrolled adults with presbyopia and self-reported asthenopia. Participants were allocated using computer-generated randomization and randomly assigned at a 1:1 ratio to RLRL or sham groups. Blinding included participants, examiners, assessors, and statisticians. The primary outcome was the change from baseline in the Computer Vision Syndrome Questionnaire (CVS-Q) score at day 31. Secondary outcomes were the change in accommodative amplitude (AA), Near Activity Visual Questionnaire (NAVQ) score, habitual near visual acuity, near-addition power, accommodative facility, positive and negative relative accommodation, binocular cross-cylinder response, and accommodative convergence-to-accommodation ratio. Continuous outcomes were analyzed using linear mixed-effects models. RESULTS: Sixty-four of 66 randomized participants (aged 41-62 years) completed the 1-month trial. At day 31, RLRL showed greater improvement than sham in CVS-Q score (adjusted mean difference, -1.75 points; 95% CI, -3.10 to -0.39), binocular AA (1.09 D; 95% CI, 0.37 to 1.82), and NAVQ score (-8.07 points; 95% CI, -14.17 to -1.97). The effect on AA was most pronounced in a subgroup of eyes with baseline amplitude >2.0 D (adjusted mean difference 1.33 D; 95% CI 0.32-2.34). Other measures did not differ between groups at each visit. No treatment-related adverse events were reported. Adherence was similar between groups (mean compliance: 98.2% vs 97.5%). CONCLUSIONS: Short-term treatment with RLRL significantly reduced asthenopic symptoms and improved accommodative amplitude in individuals with presbyopia.Trial registration: NCT06745661 (registered December 8, 2024).

Humans↗
PubMed1980

Safety and toleration of oxymetazoline ophthalmic solution.

Two studies were carried out in volunteers without any abnormal ocular conditions to assess the effects and safety of an ophthalmic preparation of oxymetazoline (0.025%). In the first study in which oxymetazoline was compared with placebo and phenylephrine, the results of infra-red electronic pupillography showed that oxymetazoline in therapeutic doses had no effect on pupil size or near point recession. The second study, which was a double-blind forced choice comparison of two different formulations against placebo and 1% naphazoline, showed from assessments of the degree of ocular discomfort and hyperaemia that oxymetazoline was well tolerated and the subjects preferred oxymetazoline in a boric acid rather than in a phosphate solution.

Accommodation, Ocular↗
PubMed2005

[Whiplash injury and visual function impairment].

Neuro-ophthalmologic manifestations of whiplash injury may be evident or quite inapparent. Presentation is made of a young woman sustaining whiplash injury, who developed visual field impairment and reduced amplitude of accommodation with pronounced asthenopic discomforts. The potential visual system lesions secondary to whiplash injury, generally manifesting as impaired accommodation and convergence, ocular motility disorders, lesions of the posterior ocular segment and visual field impairments, are systematically described.

Accommodation, Ocular↗
PubMed1987

Neurovisual adaptations to subnormal vision in children.

Neurovisual adaptations to subnormal vision in children are of practical importance and need to be remembered in the management of children with low vision. The physiological adaptations discussed include shortening the focal distance, abnormal head positions, compensatory head movements, and ocular motor search strategies. In addition the concept of neural plasticity, particularly in respect to the ability of the extrageniculate striaete system to assume primary visual function in cortically damaged children is discussed.

Accommodation, Ocular↗