Organic Amblyopia Research Articles

Le dépistage visuel chez l’enfant : les recommandations de l’Association Francophone de Strabologie et d’Ophtalmologie Pédiatrique (AFSOP)

In light of the international literature, a workgroup of experts from the AFSOP met in February 2019 to formulate updated recommendations for visual screening in children. An ophthalmologic examination during the first month of life is recommended for children at risk of developing infantile organic amblyopia. An ophthalmologic examination including cycloplegic refraction between 12 and 15 months of age is recommended for children at risk of developing functional amblyopia. At any age, a prompt ophthalmologic examination is recommended for a child suspected of functional or organic ocular pathology. In children without risk factors or warning signs, a systematic orthoptic screening examination is recommended during the third year of life, including a monocular visual acuity test, a cover-test and a refraction by photoscreener. The child is referred to the ophthalmologist only in the case of an abnormal screening result, according to the following criteria: visual acuity <5/10, or >1 difference between eyes, abnormal cover test, photodetection refraction values <-3D or>+2.5D for the sphere,>1.5D for astigmatism and>1D for anisometropia. Finally, we review normal childhood refractive errors as a function of age as well as the correct use of photo screening devices.

Decompression retinopathy following nonpenetrating deep sclerectomy for primary congenital glaucoma

BackgroundTo describe a unique case of decompression retinopathy manifesting as pre-macular subhyaloid hemorrhage that occurs in a nine-day old child after undergoing a non-penetrating deep sclerectomy for primary congenital glaucoma.Case presentationWe report a single case of a 9-day-old boy who was referred to our department of ophthalmology for bilateral buphtalmia and corneal edema. He presented marked elevation of the intraocular pressure in both eyes (22 mmHg and 26 mmHg, in the right eye and left eye respectively) associated with significant optic nerve cupping.Non-penetrating deep sclerectomy was performed for each eye, with effective reduction of the intraocular pressure during the first week postoperatively (11 mmHg and 7 mmHg in the right eye and left eye respectively). The right eye presented an isolated subhyaloid hemorrhage located in the pre-macular area, persisting 3 weeks after the initial surgery and requiring pars-plana vitrectomy to clear the visual axis. This uncommon complication was identified as decompression retinopathy.The intraocular pressure remained controlled in the normal range three years after initial surgery in both eyes, with reversal of optic disc cupping.ConclusionsDecompression retinopathy is a potential complication after non-penetrating deep sclerectomy in primary congenital glaucoma, requiring prompt treatment strategy to prevent potential organic amblyopia.

Observations on the relationship between anisometropia, amblyopia and strabismus

We investigated the potential causal relationships between anisometropia, amblyopia and strabismus, specifically to determine whether either amblyopia or strabismus interfered with emmetropization. We analyzed data from non-human primates that were relevant to the co-existence of anisometropia, amblyopia and strabismus in children. We relied on interocular comparisons of spatial vision and refractive development in animals reared with 1) monocular form deprivation; 2) anisometropia optically imposed by either contact lenses or spectacle lenses; 3) organic amblyopia produced by laser ablation of the fovea; and 4) strabismus that was either optically imposed with prisms or produced by either surgical or pharmacological manipulation of the extraocular muscles. Hyperopic anisometropia imposed early in life produced amblyopia in a dose-dependent manner. However, when potential methodological confounds were taken into account, there was no support for the hypothesis that the presence of amblyopia interferes with emmetropization or promotes hyperopia or that the degree of image degradation determines the direction of eye growth. To the contrary, there was strong evidence that amblyopic eyes were able to detect the presence of a refractive error and alter ocular growth to eliminate the ametropia. On the other hand, early onset strabismus, both optically and surgically imposed, disrupted the emmetropization process producing anisometropia. In surgical strabismus, the deviating eyes were typically more hyperopic than their fellow fixating eyes. The results show that early hyperopic anisometropia is a significant risk factor for amblyopia. Early esotropia can trigger the onset of both anisometropia and amblyopia. However, amblyopia, in isolation, does not pose a significant risk for the development of hyperopia or anisometropia.

Study of Changes in the B-Wave of Electroretinogram in Early Detection of Organic Amblyopia in Children

Background: Amblyopia or Lazy eye is a common problem among children and indicating the existence of underlying diseases such as strabismus or refractive error, and therefore its diagnosis and treatment is needed, to prevent complications in the visual system and therefore, identifying and treating these children is an important task. One of the methods proposed is the use of electrophysiological tests mainly Electroretinography (ERG), ERG deals with retina of visual system. The aim of present research is an attempt to survey the retina of these patients and look for possible changes in b wave of ERG pattern.Methods: 50 children with organic amblyopia were enrolled in this study, the demographic information of the patients was recorded in a list prepared for this purpose. The ERG, mainly the b wave was measured in the patient population. The results obtained were analyzed by software SPSS19.Results: The mean voltage of b wave in case and control group was. 34.88 and 90.96 μv respectively. The difference between the two groups is statistically significant (P<0.05),however, the latency in patients and healthy population was 86.56 and 43.6 msec respectively, which is statistically significant (P<0.05)too.Conclusion: In general we can conclude that ERG test; provide useful information about retina of the children suffering from amblyopia which will be discussed in the manuscript in detail.Keywords: Amblyopia, children, ERG b-wave

Pattern VEP in Adult Amblyopic Patients Requested From Military Service

Purpose: To evaluate the pattern VEP in adult amblyopic patients seen in consultation for ophthalmic evaluation as a past of physical examinations for conscription. Methods: We retrospectively analyzed, 67 men, 20-year-old or older, who had pattern VEP done for the diagnosis of amblyopia from January 2004 to May 2009. P100 latency and P100 amplitude were analyzed. Results: Thirteen patients were non-amblyopic, and 54 patients had amblyopia. Binocular amblyopia and monocular amblyopia were found in 23 and 31 patients, respectively. In the binocular amblyopic patients, four patients were hyperopic, seven patients were myopic, and 12 patients were astigmatic amblyopia. In the monocular amblyopic patients, 15 patients were anisometropic, 12 patients were strabismic, and four patients had organic amblyopia. The value of P100 latency and P100 amplitude were statistically significantly different between non-amblyopic and amblyopic eyes, with check size of 3232. However, the types of amblyopia among the patients were not different at a statistically significant level. Visual acuity and P100 amplitude were significantly positively correlated. Conclusions: VEP might be a useful tool for diagnosis of adult amblyopia, especially using a 3232 check size. This tool may impart the ability to decide relationship between amblyopia and visual acuity by analyzing P100 latency and amplitude values.

Visual Outcome in Children With Congenital Glaucoma

Purpose: To evaluate the prognosis of vision and the development of amblyopia in primary congenital glaucoma patients. Methods: The author reviewed 38 eyes of 22 primary congenital glaucoma patients and evaluated variables such as age at time of surgery and at the last visit, preoperative IOP, Cup-to-disc(CD) ratio, corneal diameter, refractive error, axial lengths and IOP, CD ratio and visual acuity at the last visit. According to visual acuity, the patients were divided into 3 groups, good (＞0.5), fair (0.10.5), and poor (＜0.1). The amblyopia was defined when BCVA was below 0.8 and no evidence of progression of glaucoma. There were 4 types of amblyopia: deprivation, anisometropic, strabismic and organic. The author compared the 3 groups and evaluated factors affecting the vision as well as the prevalence of amblyopia. Results: There were 17 eyes in the good group, 4 eyes in the fair group and 17 eyes in the poor group (p＜0.05). Amblyopia developed in 17 eyes with 7 eyes showing deprivation amblyopia. Anisometropic and organic amblyopia were each found in 4 eyes, and strabismic amblyopia was found in 2 eyes. The postoperative IOP and CD ratio and preoperative CD ratio were significantly lower in the good group than the other groups (p＜0.05). Conclusions: Final VA was poor in 45% of eyes with primary congenital glaucoma, and amblyopia developed in 45% of these eyes. The prognosis for vision may be related to the treatment of glaucoma and amblyopia.

Manifestaciones oftalmológicas en tumores cerebrales pediátricos: 58 casos

To describe the visual manifestations of brain neoplasms, and to analyze the effect of tumor control on these. This is a descriptive retrospective study, which includes patients under 14 years of age, suffering from different brain neoplasms in our hospital between 1996 and 2005 inclusive. In the group of patients with low visual acuity, 44% had organic amblyopias. In 28% of cases, the amblyopia was secondary to the strabismus/nystagmus produced by the developing tumor. Corrective treatment was successful in some cases of partial or total organic amblyopia. Ophthalmologic evaluation (including perimetry and fundoscopy) enabled detection of 3 tumor relapses. Visual analysis (visual acuity, perimetry, fundoscopy) should be an essential component of assessment during brain neoplasm treatment and follow-up. Corrective treatment is sometimes successful in organic amblyopias

Management of strabismus and amblyopia. A practical guide

John Pratt-Johnson and Geraldine Tillson Management of strabismus and amblyopia. A practical guide. Second edition. 308 pages Thieme Medical Publishers, New York, 2001 ISBN: 0-86577-992-9 Price: US$ 89 In 1994, the first edition of this textbook on strabismus and amblyopia by John Pratt-Johnson and Geraldine Tillson from Vancouver appeared. Both authors were well-known and significant contributors to clinical strabismology through many publications. Now this book is available in a second edition. The first edition of this book has already been appreciated by many strabismologists working in clinical practice. Like this edition, the second edition is well written, with clear sections, reflecting the vast experience of a life-long devotion to strabismus. After the two first chapters on physiology and pathology of binocular vision, there is a pearl of a practical chapter about the first visit. Then follows sections on sensory and motor evaluation of strabismus, before the different kinds of strabismus are outlined in succeeding chapters. Towards the end of the book the authors deal with some specific problems: strabismus in adults, general aspect of extraocular muscle surgery, surgical complications, head tilt, double vision, nystagmus and common mistakes in the management of strabismus. The last chapter is devoted to the issue of preventing amblyopia in the developing countries. Som points of discussion may be mentioned. The term “organic amblyopia” (p. 77) is to me a contradiction, and should better be avoided. Dealing with weakening surgical procedures on the oblique muscles (examples on p.96 and 144–146), myectomy (inferior oblique) and tenotomy (superior oblique) are almost exclusively taken into account. According to most European authors, controlled recession procedures should be preferred. In my opinion, the authors of this book should have presented both these options. Likewise, in the section about sixth nerve palsy (p. 177), only Jensen’s procedure is presented as a possible surgical method. Many strabismus surgeons would perhaps prefer Hummelsheim’s or O’Connor’s procedure, and in a strabismus textbook I think all these three methods should have been presented and discussed. The difference between the first and the second edition is minor. Most of the chapters are virtually unchanged, but some references have been added. As far as I have seen, no additional illustrations appear in the new addition. The main difference is two additional chapters, one about common mistakes in the management of strabismus (which indeed is a clinically important and well-written chapter) and one about strabismus and amblyopia in developing countries. One piece of information that I miss in the new edition is about the fibrous tissue apparatus in the orbit making up the so-called pulleys. A number of publications the last 5–6 years have shown that these structures probably serve as functional origins of the extraocular muscles. In addition, it has also been shown that displacement of these pulleys may mimic A- or V-patterns. Thus, they may clearly have clinical and practical implications. This book is not a comprehensive volume in the field of strabismus and binocular vision, but a short, practical and clinical textbook, which hereby is recommended.

The Fate of the “Sound” Eye in Unilateral Congenital Cataract

Should emergency surgery be performed in the case of a unilateral congenital cataract in order to preserve the functional future of the anatomically intact eye? The answer may be found in congenital “Monophtalme” syndrome which appears during the first months of life with severe unilateral congenital organic amblyopia. The vision of the “sound” eye does not develop normally because there is no symmetrical binocular stimuli during these first few months of life. The fixation thus remains immature with an attraction of the fixation-pursuit system towards adduction. The clinical complications that result are: (a) a preference towards adduction which induces a torticollis; (b) a manifest/latent nystagmus (Drift/Adduction) of variable intensity with impaired vision in the Primary Position (PP). The more severe the organic defect, the more pronounced the visual functional defect of the viewing eye. Very early cataract extraction seems to attenuate the symptoms, probably because it allows more symmetrical (light?) retinal stimuli during the development of monocular fixation.

Grating and Recognition Acuities of Pediatric Patients

Acuities for gratings obtained by preferential looking (PL) that differed from expectations based upon the ophthalmologic examination prompted this study. Older pediatric patients (124 patients; mean age, 6.5 years) were tested by the PL grating test and a test of recognition acuity (pictures or letters). On the average, grating acuity was better than recognition acuity. In patients with dense amblyopia or foveal abnormalities, very large discrepancies between grating and recognition acuities were found. In nonamblyopic patients, acuities were no more discrepant than for children with normal eyes. Amblyopia was less dense by grating acuities than by recognition acuities; grating acuities were sensitive, however, to refractive and organic amblyopia but not to strabismic amblyopia. Possible explanations include the heterogeneity of patients' eye disorders, single vs. linear acuity, stimulus size and relative complexity of stimuli. These results can aid in evaluating PL grating acuities of preverbal patients, and suggest modifications of stimuli to investigate amblyogenesis.

Differences in the neural basis of human amblyopias: The effect of mean luminance

The effect of reducing background luminance on contrast thresholds for different forms of amblyopia was investigated. As expected from previous acuity studies strabismic and organic amblyopia exhibit dramatically different behaviour; for a particular spatial frequency the degree of strabismic amblyopia reduces with reducing luminance whereas organic amblyopia does not. Unexpectedly, there is a similar difference in the behaviour of strabismic and anisometropic amblyopia. This difference suggests that these two forms of “functional” amblyopia do not have identical neural bases. An hypothesis concerning the extent of the abnormality within the visual field is advanced to explain these luminance dependent results.

Monocular Performance of Functional Amblyopes

The traditional scotoma hypothesis for functional amblyopia is modified to state: whereas the central visual field of a normal visual system and that of an organic amblyope become increasingly scotomatous as light level is decreased from high to low photopic levels, the reverse is true for the central field of a functionally amblyopic visual system. An attempt is made to show how this hypothesis provides a unifying explanation for several seemingly different visual performances observed in functional amblyopes. The paper deals with (1) field inhomogeneities and threshold measures, and (2) threshold changes with light adaptation level. Implications of the modified scotoma hypothesis are discussed for (1) the neutral-density-filter test to distinguish functional from organic amblyopia, (2) the reduced CFF threshold for amblyopic eyes, (3) expectations of stereopsis for amblyopes, and (4) possible mechanisms for amblyopia.

Visual functions after perinatal macular haemorrhage.

Perinatal macular haemorrhage has been suggested as being a cause of amblyopia and strabismus. 39 of 48 children with macular haemorrhage after birth were examined at the age of 5 years. The study comprised visual acuity with E-test types and cycloplegic refraction. Binocular function was evaluated by cover test, and 4d-prism test. Fixation was studied by an ophthalmoscope with a central dark star. Sensory function was estimated by Schober test and Worth 4-dot-test. The observations gave no support to the existence of organic amblyopia or strabismus following perinatal macular haemmorrhage.

Factors involved in the production of amblyopia.

If amblyopia is defined as reduced visual acuity in an eye which appears normal on examination, then it is necessary to distinguish between several related, similar, or different conditions that fit this definition. Six years ago I proposed a classification of amblyopia in which the various factors leading to its development were enumerated in the light of our clinical knowledge at that time (von Noorden, I967). Meanwhile, with the advent of modern neurophysiological techniques, amblyopia has become a favourite research subject of neurophysiologists and neuroanatomists, and the effect of abnormal visual experience early in life on visual functions of the adult organism is currently being explored on a large scale in lower animals and in monkeys. Some of this information has direct bearing on our concept of amblyopia as it occurs in human patients. The purpose of this paper is to discuss the extent to which our conventional concept of the various factors that cause amblyopia in humans may have to be modified in light of this new information. This discussion will be limited to amblyopia in association with strabismus, anisometropia, and form vision deprivation; organic amblyopia and that associated with nystagmus, achromatopsia, or nutritional deficiencies will not be considered. Let us briefly review the factors that have been held responsible for the production of each type of amblyopia.

Retinal hemorrhage in newborns and organic amblyopia.

It has been suggested that retinal hemorrhages at birth may be the cause of organic amblyopia and strabismus later in life. Of 1,000 newborns examined within the first 24 hours of life, we found 245 cases with retinal hemorrhages; the macula was involved in 18 patients. Five children who had macular hemorrhages at birth were available for reexamination; visual acuity and ocular motility were normal. On the basis of this study we conclude that macular hemorrhages at birth do not play a significant role in the cause of amblyopia or strabismus.

Visual Rehabilitation in Cases of Svere Organic Amblyopia

Visual Rehabilitation in Cases of Svere Organic Amblyopia

Macular disease and amblyopia. The visual-evoked response.

The amplitude of the visual-evoked cortical response (VER) elicited by stimulating one eye was compared with that elicited by stimulation of the fellow eye in one normal subject on 30 occasions and in 30 normal subjects on single occasions. The extent to which these responses varied was then used as a basis in evaluating the VER differences seen in patients with unilateral macular disease, refractive amblyopia and strabismic amblyopia. Significant VER differences were found in those patients with unilateral macular disease and in one patient with probable organic amblyopia. No significant VER differences were found in patients with refractive or strabismic amblyopia.