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Query: UMLS:C0038379 (strabismus)
 9,317 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Physiological experiments, involving recording from the visual cortex in young kittens and monkeys, have given new insight into human developmental disorders. In the visual cortex of normal cats and monkeys most neurones are selectively sensitive to the orientation of moving edges and they receive very similar signals from both eyes. Even in very young kittens without visual experience, most neurones are binocularly driven and a small proportion of them are genuinely orientation selective. There is no passive maturation of the system in the absence of visual experience, but even very brief exposure to patterned images produces rapid emergence of the adult organization. These results are compared to observations on humans who have "recovered" from early blindness. Covering one eye in a kitten or a monkey, during a sensitive period early in life, produces a virtually complete loss of input from that eye in the cortex. These results can be correlated with the production of "stimulus deprivation amblyopia" in infants who have had one eye patched. Induction of a strabismus causes a loss of binocularity in the visual cortex, and in humans it leads to a loss of stereoscopic vision and binocular fusion. Exposing kittens to lines of one orientation modifies the preferred orientations of cortical cells and there is an analogous "meridional amblyopia" in astigmatic humans. The existence of a sensitive period in human vision is discussed, as well as the possibility of designing remedial and preventive treatments for human developmental disorders.
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PMID:Modification of visual function by early visual experience. 82 72

Amblyopia is a preventable cause of visual loss in children that may be permanent unless it is detected and treated early. It may be caused by strabismus, refractive errors, or cataracts. Primary strabismus may lead to loss of vision from amblyopia and the loss of binocularity. Secondary strabismus may be a sign of primary visual loss in one or both eyes. The most serious disorder that may present as secondary strabismus is retinoblastoma. It is imperative to detect retinoblastoma early because of its morbidity and mortality. Amblyopia is detected by assessing the visual acuity of each eye. Strabismus is detected by using the corneal light reflex test and the cover test. Focusing problems are detected by assessing the visual acuity and the red reflex. Cataracts and retinoblastoma may be detected by examining the red reflex of the eye. Treatment of amblyopia consists of correcting the amblyogenic factor with appropriate glasses and surgery. The preferred eye is patched with an adhesive patch to stimulate visual development in the amblyopic eye. The pediatrician plays a crucial role in the early detection of amblyopia, strabismus, and cataracts. The key to successful visual outcome is early recognition by the pediatrician, referral to the pediatric ophthalmologist, and prompt treatment.
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PMID:Amblyopia: etiology, detection, and treatment. 173 42

Visual success in the treatment of monocular congenital cataracts requires early surgery, and aggressive, long-term amblyopia management and optical correction. These children will have their only normally seeing eye patched for a significant percentage of their early childhood years. We have been concerned about the possibility of an adverse psychological impact of this form of treatment. This study utilized two standardized testing instruments to evaluate the incidence of developmental delay and behavioral problems in children treated for monocular congenital cataracts. A total of 22 children were evaluated with one or both of these instruments and compared to a control group of 18 normal siblings. There was no statistically significant evidence of developmental delay or increased behavioral problems in the treatment group.
J Pediatr Ophthalmol Strabismus
PMID:Monocular congenital cataracts: psychological effects of treatment. 195 57

Two children developed profound visual loss in the eye being patched full time because of strabismic amblyopia in the fellow eye. The first had been patched for 13 days at age 18 months. Complete resolution was noted on the 40th day of reverse occlusion. The second had been patched for 1 month at age 9 months. After 3 months without treatment, reverse occlusion was instituted and was continued for 3 years. Mild amblyopia persists in both eyes of the second child. Although rare, occlusion amblyopia can occur in young children being patched full time. We usually avoid full-time occlusion and monitor patients at intervals at least as frequent as 1 week per year of age.
J Pediatr Ophthalmol Strabismus
PMID:Severe visual loss resulting from occlusion therapy for amblyopia. 368 11

We implanted nine intraocular lenses for the aphakic correction of congenital monocular cataracts in eight children (eight eyes). During follow-up periods ranging from 18 to 50 months in six children, there were no major complications connected to the surgery. Parental cooperation with treatment for amblyopia was satisfactory in all cases. The degree of strabismus, the fixation pattern, and the optokinetic nystagmus responses improved postoperatively in all six. Three children old enough to cooperate during visual testing had visual acuities better than 20/200 and two of these had visual acuities of 20/40. In all six children the sound eye is still patched for three to six hours a day. All six attend regular kindergartens and participate in their normal activities without difficulty.
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PMID:Congenital cataract and intraocular lenses. 661 10

Evoked potential measurements of visual acuity were made on four children aged from 5 months to 8 years. They were deprived of normal visual stimulation by various disorders: unilateral aphakia from a congenital cataract, vitreous hemorrhage, polar cataract, and esotropia. In the two younger children, aged 5 and 15 months, respectively, the visual acuity improved when the eye had good optical imagery and declined with poor or no imagery. Reversal of the imagery to the contralateral eyes again brought large changes in opposite directions. In the two older children, aged 4 and 8 years, respectively, there were marked decreases in acuity in the patched eye, but little or no change in the unpatched eye. It is not know whether these differences are due to age or to the original kind of visual disorder, such as deprivation, occlusion, or strabismus, or are merely individual differences. It is clear, however, that some children exhibit large changes in acuity in response to visual deprivation or patching, or to its removal, in a readily reversible manner. Also, we have demonstrated that visually evoked potential acuities may be obtained from pediatric, clinical patients without regard to age, which may be useful in management of the conditions.
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PMID:Effect of natural deprivation and unilateral eye patching on visual acuity of infants and children. Evoked potential measurements. 725 17

A retrospective study of fifty 5-year-old children whose eyes were patched bilaterally to treat neonatal jaundice was compared with a study of a similar group of fifty 5-year-old children who were treated in the intensive care nursery but whose eyes were not patched. No difference in the incidence of strabismus or loss of stereoacuity was established in these two groups. Despite the experimental evidence documenting changes in the visual cortex and interocular alignment in animals binocularly deprived of visual stimulation near birth, the clinical practice of binocularly patching the eyes of neonates with jaundice does not seem to increase the incidence of subsequent strabismus or loss of stereoacuity.
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PMID:The long-term visual effects of short-term binocular occlusion of at-risk neonates. 743 27

Fourteen nonstrabismic volunteers were monocularly patched for 2 and 24 hours in separate experiments. Horizontal and vertical phorias were measured at 6 m and 30 cm, at 30-second intervals, for at least 30 minutes, following removal of the patch. After 24 hours of monocular occlusion, the initial change from baseline at 6 m ranged from 9.5 prism diopters exo to 7 delta eso and 6.5 delta hyper to 3 delta hypo. At 30 cm, the initial change ranged from 7.5 delta exo to 4 delta eso and 1 delta hyper to 1 delta hypo. In all but three subjects, phorias returned to within 2 delta of baseline by 3 minutes, and in all subjects by 25 minutes. After 2 hours of monocular occlusion, the range of initial change from baseline was similar to 24 hours of occlusion, but all phorias returned to within 2 delta of baseline by 2.5 minutes. Therefore, we suggest that ocular alignment should not be routinely measured within 3 minutes of removing a patch. If patched for 24 hours, a few individuals will require up to 25 minutes for stabilization of their deviation. Further studies might address these effects in patients with subnormal fusion and stereopsis.
J Pediatr Ophthalmol Strabismus
PMID:Recovery of phorias following monocular occlusion. 801 83

We developed a coinsized occlusion dose monitor (ODM) to measure compliance with patch-wearing during the treatment of amblyopia objectively. It measures the temperature difference between the front and back of the ODM every 2-5 minutes by means of two thermistors. The data is stored in EEPROM memory and read out after recording for a week by connecting it to a PC. The ODM measures 35x23x4 mm and weighs 6 g. The back of the ODM is glued to the front of the amblyopia patch with double-sided Scotch tape. When the patch with the ODM is on the eye, the temperature at the back of the ODM is higher than at the front. Compliance is being studied in children taking part in a large amblyopia cohort study. The parents were instructed during home visits every three months to put the ODM on the patch. After a week, the ODM was collected and read out. Although the parents knew that a recording was being made, compliance was mediocre in many cases. Children were patched infrequently, for 5 minutes only, for long periods on the last days of the recording, at night, etc. Diaries detailing patch time were unreliable.
Strabismus 1999 Jun
PMID:Electronic monitoring of treatment compliance in patching for amblyopia. 1042 Feb 16

Recent studies suggest that children with amblyopia associated with anisometropia, strabismus, or both should be treated initially with best refractive correction until visual acuity is stable. This may take several months, and a proportion of children will achieve equal visual acuity with glasses alone. For residual anisometropic and strabismic amblyopia, the initial choice of patching or atropine should involve the parent and the child. The dose of prescribed patching or atropine may initially be quite modest, such as 2 hours of patching a day or twice weekly atropine. Treatment should be offered to children until at least 12 years of age and possibly to teenagers. Ongoing studies are addressing the role of undertaking near activities while patched and the role of atropine for severe amblyopia and for older amblyopic children. Future studies are needed to investigate the best treatment strategies for residual amblyopia, whether weaning treatment is needed at the end of a course, and how compliance can be enhanced.
Strabismus 2006 Mar
PMID:The treatment of amblyopia. 1651 68


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