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PubMedDate not supplied

Reversal of myopic anisometropic amblyopia with phakic intraocular lens implantation.

PURPOSE: To report a case of reversal of myopic anisometropic amblyopia with phakic intraocular lens implantation. METHODS: A 6-year-old boy with anisometropic amblyopia with spherical equivalent refraction of right eye: -14.00 -3.00 x 100 degrees, left eye: -0.50 -3.25 x 90 degrees, was treated for 2 years with occlusion to the left eye, with poor results. Refractive surgery was planned because of contact lens intolerance at age 8 years. A -15.00-D iris claw Artisan intraocular lens (IOL) was implanted. RESULTS: Following surgery, treatment of the amblyopia and spectacle correction of -4.00 D cylinder at 85 degrees in the right eye and -3.50 D cylinder at 90 degrees in the left eye was necessary. Visual acuity 6 months after surgery was 20/25 in the right eye and 20/20 in the left eye, and has remained stable 18 months after surgery. CONCLUSION: Myopic anisometropic amblyopia in an 8-year-old boy was treated successfully with implantation of an Artisan iris claw phakic anterior chamber IOL, combined with occlusion therapy, and resulted in reversal of amblyopia.

Amblyopia↗
PubMed1994

Pathophysiology of binocular vision and amblyopia.

This article focuses on three important issues that have received much attention during the past year. The first is sensitive periods for amblyopia. Recent physiological studies suggest a surprising degree of neural plasticity in the adult visual cortex. A review of the literature suggests that at least some human amblyopes retain cortical plasticity into adulthood. The second issue is new methods of treatment for amblyopia. Certain neurotransmitters have been implicated in neuronal plasticity. Based on this finding, a potentially promising new method for treating amblyopia, levodopa, is being tested in adults and children with amblyopia. Unfortunately the early results provide more questions than answers. The third topic is neural mechanisms of amblyopia. In primates and humans, the weight of evidence suggests that the neural effects of strabismus and anisometropia are expressed primarily in the cortex. These cortical effects are expressed in a loss of cortical neurons and in alterations in the contrast sensitivity and range of preferred spatial frequencies of the neurons dominated by the amblyopic eye. The relationship between these physiological effects and psychophysical performance is reviewed.

Amblyopia↗
PubMed2000

Listing's law in strabismus and amblyopia: a preliminary report.

We investigated whether Listing's law applies in patients with diminished or no stereopsis due to strabismus or amblyopia. Eye movements of normal subjects and patients with strabismus and/or amblyopia were recorded during monocular and binocular fixation; from these data the shape and relative orientation of displacement planes were calculated. In normal subjects, monocular or binocular fixation did not influence the thickness and relative orientation of displacement planes. No differences were found between normals and the patient with amblyopia due to anisometropia. In one patient with strabismus but without amblyopia, the orientation of displacement planes depended on the fixation conditions; a coupling between horizontal vergence effort and plane orientation was observed. Patients with amblyopia and strabismus showed abnormally shaped and/or abnormally orientated displacement planes, which depended on the fixation conditions. Differences between both eyes in the shape of the planes were also observed. These results show that normal Listing behavior can be present in subjects with diminished stereopsis. They also show that normal stereopsis does not necessarily mean normal Listing behavior, suggesting that Listing's law is mainly a result of motor strategy.

Adult↗
PubMed2000

Prevalence of amblyopia and associated refractive errors in an adult population in Victoria, Australia.

The study aimed to describe the prevalence of amblyopia and associated refractive errors among an adult Australian population. The Visual Impairment Project (VIP) is a population-based study of age-related eye disease in the state of Victoria, Australia. Data were collected through standardised interviews and orthoptic and ophthalmic dilated examinations. Amblyopia was defined as best-corrected visual acuity of 6/9 or worse in the absence of any pathological cause. The participants were 3,265 urban residents and 1,456 rural residents of the VIP ranging in age from 40-92 years (mean = 59 years; 53% female). The prevalence of unilateral amblyopia was 3.06% (95% C.I. 2.59, 3.53). Amblyopia was not found to be statistically different by age group (p=0.096), gender (p=0.675), or place of birth (p=0.14). Anisometropia was statistically more common (p<0.001) in amblyopic cases (51.1%) compared to the normal population (9.7%), and 54% of amblyopic eyes had visual acuity of worse than 6/12. Amblyopia is a significant cause of unilateral reduced visual acuity in a population aged 40 years and older. Anisometropia was more prevalent and the degree of anisometropia was greater in the amblyopic group compared with the normal population. Oblique astigmatism was more prevalent in the amblyopic group compared with the normal population.

Adult↗
PubMed2002

Bilateral ametropic functional amblyopia in genetic ectopia lentis: its relation to the amount of subluxation, an indicator for early surgical management.

To determine the visual results of conservative (non- surgical) therapy, we reviewed all our patients with genetic ectopia lentis, with and without Marfan's Syndrome. Of these patients, 50% had significant permanent (or potentially so) ametropic functional amblyopia (visual acuity 20/50 to 20/200) in spite of good conservative management. This was especially true (100%) if the amount of lens dislocation was such that the lens edge was approaching the center of the pupil (vision still primarily phakic). The worst amblyopia was noted when the lens was still covering the visual axis and the lens edge was 1.3 mm from the center of the pupil (range of 0.3 to 2.3 mm). With regard to the most serious complication of ectopia lentis and its treatment, retinal detachment, when it occurred in our patients it was more strongly related to axial high myopia than surgery, per se. Since the axial high myopia which characteristically develops in ectopia lentis is probably the result of the amblyopia or the amblyopiagenic optics of ectopia lentis, lentectomy may be indicated early in this condition, before the axial high myopia develops, to prevent both axial high myopia and the attendant risks of retinal detachment as well as functional amblyopia. If the refractive error cannot be corrected well and the resultant ametropic amblyopia does not respond to conservative management, early surgery should be considered. If the lens is subluxated so that the edge of the lens approaches to within 0.3 to 2.3 mm of the center of the pupil (with best correctable vision still phakic), this is highly probable.

Adolescent↗
PubMed2002

[Unilateral myelinated nerve fibers associated with myopia or amblyopia].

There are described a number of 9 clinical cases with unilateral myelinated nerve fibers, associated with myopia or amblyopia. Four cases developed extended myelinated areas, anisometropia with increased values, accentuated amblyopia and macular changes. Patients underwent treatment for amblyopia through correction with spectacles lenses and the occlusion of the congenerous eye. The obtained functional results differentiated the casemix in two groups: with therapeutic failure, 4 cases, characterized by extended myelination, anisometropia with an average of over -10 diopters and macular changes. with therapeutic success, 5 cases, characterized by reduced myelination, anisometropia with an average of over -4 diopters and normal maculae. It has been found a significantly statistical difference between the two groups as regarding the value of the anisometropia. However, the macular aspect has been an important factor in order the therapeutic effect to succeed. This clinical syndrome is differentiated from the unilateral simple myopia with amblyopia and from the myelinated nerve fibers without myopia or amblyopia.

Amblyopia↗
PubMed1992

[Measuring the threshold of stereopsis for 111 children with amblyopia].

The threshold of stereopsis was measured by static stereopter for 111 children with amblyopia aged from 4 to 13 years. They were divided into three groups: 38 cases ranging in age from 4 to 5 years, 43 cases 6 to 7 and 30 cases 8 to 13. Fifty six cases were unilateral and 55 bilateral amblyopia. The average threshold of stereopsis was 149.64 second angle for the 4-5 group, 66.69 for the 6-7 and 48.48 for the 8-13. The average threshold for unilateral amblyopia was 65.3, in which mild type was 38.6 and under moderate type was 88.84, whereas the average threshold for bilateral cases was 115.81, in which mild type was 44.09 and under moderate type was 175.44. The distribution of stereopsis for different age groups, the threshold of stereopsis influenced by different types of amblyopia and the comparison of amblyopia between bilateral and unilateral are also discussed.

Adolescent↗
PubMedDate not supplied

[Principles of background stimulation in the treatment of amblyopia].

Described in the paper are the results of a comparative evaluation of treatment of amblyopia by computer techniques based on the modern understanding of the mechanisms of impaired visual functions, as observed in amblyopia, comprising stimulation of different canals of the visual system, which were affected or not. Better clinical-and-functional results were fixed in patients with high amblyopia by using the "Ambcar" soft stimulating the magnocellular system by sinusoidal grates with the eyes being fixed on moving objects as well as in patients with moderate amblyopia by using the "eYe" and "Krestiki" soft tools affecting different canals of the visual system and different levels of the parvocellular system. Amblyopia should be treated with respect to individual differences between affected functions of the visual system in each patient, and a therapy method should be chosen in proportion to a disease severity.

Acoustic Stimulation↗
PubMed2005

[Functional state of visual system in amblyopia].

Amblyopia is a reduction of sight (with optimal optical correction) that is not associated with organic changes of the eye or a visual pathway. Being complex in its pathophysiological mechanisms, amblyopia still remains not completely explored. The purpose of our research was to reveal the symptoms of functional disturbances of visual system at various kinds of a high degree amblyopia. Clinical studies were based on the analysis of results of 72 patients with strabismic and anisometropic amblyopias at the age from 5 to 17 with visual acuity from 0,05 up to 0,2 on the amblyopic eye, and also 10 healthy children. Along with the routine ophthalmological methods of investigation, the psychophysical methods were used in order to study spatial contrast sensitivity (SCS) and color contrast sensitivity ("ON-OFF"). Functional anomalies in amblyopic eyes are characterized by a decrease in spatial contrast, color and contrast sensitivity in a greater degree in paracentral zone (5-10 degrees ), that probably testifies to the localization of the greatest functional changes in this area at the level of retina and does not exclude the possibility of derangement of interreceptor relations at the level of external and internal layers of the retina, as well as afferent inhibitory influence of the central areas of the visual system. Changes in various channels of visual system and topography of these changes help to understand the mechanisms of disturbances of visual functions in amblyopia, can shed light on the localization of functional changes at this pathology and make possible to seek the ways for adequate influence on the visual system.

Adolescent↗
PubMed2005

[Progress in research of strabismus and amblyopia in China in the new century].

In the last 5 years, we witnessed the progress in the basic and clinical research of strabismus and amblyopia in China, which should be attributed to the effective leadership of the Chinese Ophthalmological Society and the efforts of all members of the professional team. We are glad to see the work of our researchers and clinical scientists in the studies on the molecular and neuronal mechanisms of amblyopia, visual developmental plasticity and functional brain imaging of amblyopia, in the studies on the extraocular muscle's pulley and in the studies on the diagnoses and therapies of strabismus and amblyopia, and furthermore, in epidemiological studies of strabismus and amblyopia. We expect more fruits and creative findings in this field in China in the next decade.

Amblyopia↗
PubMedDate not supplied

[Optical coherent tomography in the diagnosis of amblyopia].

The central retinal area was studied in children with different types of amblyopia, by using optical coherent tomography. The results of the latter performed in 113 (208 eyes) children with different types of amblyopia were analyzed. Amblyopia was found to be characterized by structural changes in the central retinal area, which were more pronounced in its dysbinocular form. In obscurant amblyopia, these changes depended on the remoteness of deprivation. The preliminary results given suggest that the similar studies are promising in choosing an algorithm of treatment for such a severe abnormality as amblyopia.

Adolescent↗
PubMed1990

[The prevalence of refractive, anisometropic amblyopia in adults without strabismus and with contact lens correction].

The paper presents results after examination of 1260 adults (2547 eyes), aged from 18 to 55 years, for the period from 1982 to 1988. The examination was carried out in order to reveal the incidence of refractive, anisometropic amblyopia without strabismus in persons using glasses (a control group) and contact lenses as well as to determine a degree of spheric, astigmatic refraction in development of amblyopia on the background of contact lenses. It was found that amblyopia on the background of contact correction, as compared with glass correction, develops rarer making up 22.03% of them low degree of amblyopia is recorded in 51,16%, moderate--in 35,65% high--in 13,19% to the total number of amblyopic eyes examined. Direct relationship between the number of amblyopic eyes and degree of astigmatism and anisometropia is revealed. Detection of amblyopia in adults without strabismus with subsequent contact correction and treatment is considered to be necessary for medical and labour rehabilitation of such patients.

Adolescent↗
PubMed1990

[Case finding of amblyopia in young children using the TNO-depth-vision-test].

To evaluate the policy in amblyopia detection by pre-school health care workers we studied the prevalence of amblyopia that had not previously been detected among 1975 children at the ages of 4 years 6 months to 5 years 10 months. Seventy-eight (3.9%) of the children had insufficient stereo-acuity, though no form of ocular abnormality had been noted in the past. Twenty-one (1%) of the children had a previously undetected amblyopia. After 1 1/2 years 74% of the children with amblyopia had a visual acuity of 0.9 or more, while most of the children--at the time of referral--were 4 1/2 years or older. Amblyopia can be identified earlier by (a) a proper transfer of information from pre-school health care workers to the school doctor; (b) taking into consideration low vision if assessment of vision was not successful in the first examination, and (c) performing at least the TNO-stereotest when in doubt.

Amblyopia↗
PubMed1979

Is amblyopia a peripheral defect?

A class of retinal ganglion cells, the 'sustained' or 'X' cells in the area centralis of the retina, provides the physiological basis of high visual acuity. Our hypothesis, that amblyopia is a functional loss of X-cells due to inappropriate stimulation of the fovea by habitually blurred images during the critical period of development, has been supported by experiments on kittens reared with various types of surgically produced squint or with penalization. Amblyopia was associated with a loss of visual acuity of X-cells in the area centralis of the squinting eyes which had lost the ability to fix or of the penalized eyes, i.e. amblyopia occurred in the eyes which received habitually blurred images during the critical period of development. Thus amblyopia has a peripheral (retinal) cause. Regardless of whether or not the eye was amblyopic, a loss of binocularly driven cells in the visual cortex was a common feature in all uniocularly treated cases. When one eye was amblyopic the cortical cells tended to favour the non-amblyopic eye and the number of cells driven by the amblyopic eye was reduced. These central effects may play a role in suppressing unwanted images from the amblyopic eye while the fixing eye is in use. But the central effects do not cause amblyopia.

Amblyopia↗
PubMed1995

[Measurement of the visual acuity to networks with the Teller's cards: efficient detection of amblyopia in infants and young children?].

The reliability of measurement of visual acuity by Teller's card was studied in young children under 18 months (3 to 42.5 months) to detect amblyopia. Repeated tests with Teller's cards were performed in children (two exams at least) divided into several pathologies. Visual acuity changed over time (in 2000 exams). Results were compared with those given by drawing tests (Pigassou) at two years and a half. Middle amblyopia occurred in 44%, low amblyopia in 40% and high amblyopia in 16%, as the results by Teller's cards were considered as normal. These results were found in 54% among the 2000 Teller's studied. Teller's test was thus shown to be unreliable to detect middle or low amblyopia. Objective réfraction is required.

Amblyopia↗
PubMedDate not supplied

[The combined treatment of amblyopia by the methods of acupuncture reflexotherapy and traditional pleoptics].

Fifty-two children (75 eyes with amblyopia) were treated by acupuncture and traditional pleoptics. This complex of treatment was found more effective as against traditional pleoptics alone (70 children, 118 eyes with amblyopia) on the whole and in the treatment of high amblyopia. The best results were attained in children previously treated by pleoptic methods with special equipment (older children). Of the 17 eyes with amblyopia resistant to common treatment multiple-modality treatment resulted in improvement in 10 (58.8%). The effect of treatment persisted for 3 months. The first course of such treatment proved to be the most effective in the treatment of high amblyopia; starting from the second course the condition grew resistant to such treatment, this resistance gradually augmenting.

Acupuncture Points↗
PubMed1996

Results of occlusion therapy in anisomyopic amblyopia with myelinated nerve fibers.

The combination of anisomyopia and myelinated nerve fibers in the highly myopic eye is often correlated with severe and therapy-resistant amblyopia. There are very few reports on successful amblyopia therapy in patients with this constellation of symptoms. We report on six patients aged 6, 7, 9 (two cases), and 28 years (two cases) who presented with anisomyopia, myelinated nerve fibers, and severe amblyopia in the highly myopic eye. The four younger patients took part in a therapeutic trial with contact lens correction and occlusion. The six patients suffered from varying degrees of anisomyopia, which ranged between -3.5 and -18.5 D. Four patients underwent strict occlusion therapy. The best visual improvement was from 1/25 to 0.2 (factor of 5) and the best final visual acuity was 0.4. Two patients had microstrabismus, three displayed exotropia, and one patient showed no strabismus. The combination of unilateral high-grade myopia and myelinated nerve fibers represents a special conjunction that is usually correlated with severe amblyopia. The amblyopia is practically resistant to therapy, even under strict treatment regimen with contact lenses and forced occlusion. The goal must be to diagnose this constellation in the first 2 years of life. As case reports show in the literature, consistent therapy at this age can lead to good visual acuity.

Adult↗
PubMed1998

[Relation of anisometropia and the extent of amblyopia].

The author deals with the problem of impaired binocular vision in children and the problem of the relationship of amblyopia and different refractions of the two eyes. Controversial views in the literature ar corrected by the author's evaluation of her own material, i.e. refraction of 939 children aged 3-6 years subjected to sciascopy during cyclopegia. The author concludes that in isometropia and low grade anisometropia various grades of amblyopia are found in monocular strabism. When the refractory difference is higher than 1 dioptre there is already a direct relationship between the level of anisometropia and the depth of amblyopia which is particularly marked when the difference is higher than 2 diopters. In amblyopia without strabism the relationship between amblyopia and anisometropia is unequivocal.

Amblyopia↗