Afectación ocular como primera y única manifestación del síndrome de Bardet-Biedl: presentación de un caso / Ocular impairment as the first and only manifestation of Bardet–Biedl syndrome: A case report

El síndrome de Bardet-Biedl (SBB) es una ciliopatía que se asocia principalmente a distrofia retiniana, disfunción renal, polidactilia posaxial, obesidad, déficit cognitivo e hipogonadismo. Los síntomas vinculados a la distrofia retiniana no suelen aparecer hasta la primera década de vida, por lo que la detección tiende a retrasarse. La afectación ocular puede ser la forma inicial de manifestación de este síndrome, incluso puede ser la única, por lo que se debería tener en cuenta en el diagnóstico diferencial de una ambliopía en un niño que no mejora a pesar del correcto cumplimiento del tratamiento. Se presenta un caso de baja agudeza visual (AV) en una paciente pediátrica como manifestación inicial que lleva al diagnóstico del SBB y que es, además, el único síntoma que exhibe hasta la fecha, a pesar de tratarse de una enfermedad multisistémica.(AU)

Bardet–Biedl syndrome is a ciliopathy mainly associated with retinal dystrophy, renal dysfunction, post-axial polydactyly, obesity, cognitive deficit and hypogonadism. The symptoms associated with retinal dystrophy do not usually appear until the first decade of life, so the diagnosis is usually delayed. Ocular involvement may be the initial form of manifestation of this syndrome, it may even be the only one, so it should be taken into account in the differential diagnosis of amblyopia in a child who does not improve despite correct compliance with treatment. A case of low visual acuity in a pediatric patient is presented as an initial manifestation that leads to the diagnosis of Bardet–Biedl syndrome, and which is also the only symptom that the patient presents to date, despite being a multisystem disease.(AU)

Effects of acupuncture on vision and visual function in children with anisometropic amblyopia. / é’ˆåˆºå¯¹å±ˆå ‰å‚å·®æ€§å¼±è§†æ‚£å„¿è§†åŠ›å’Œè§†åŠŸèƒ½çš„å½±å“.

OBJECTIVES: To observe the clinical efficacy of Tiaoqi Tongjing Mingmu acupuncture (acupuncture for regulating qi, unblocking meridians and brightening eyes) combined with conventional treatment for anisometropic amblyopia children. METHODS: A total of 76 children with monocular anisometropic amblyopia were randomized into an observation group (38 cases, 2 cases dropped out) and a control group (38 cases). The lens covering therapy was adopted in both groups. The conventional treatment i.e. red flash, grating and visual stimulation was given in the control group, 5 min for one item each time; on the basis of the treatment in the control group, acupuncture was applied at bilateral Jingming (BL 1), Cuanzhu (BL 2), Fengchi (GB 20) and Guangming (GB 37) in the observation group. Both groups were treated once every other day, 3 times a week for 4 weeks. Before and after treatment, the best corrected visual acuity, the latency and amplitude of P100 wave of pattern visual evoked potential (P-VEP), the diopter (spherical equivalent [SE]) were observed, the stereoacuity was measured by Titmus stereoscopic examination, and the clinical efficacy was evaluated in both groups. RESULTS: Compared with those before treatment, the best corrected visual acuity improved (P<0.05), the latency of P-VEP P100 wave was shortened and the amplitude of P-VEP P100 wave was increased (P<0.05), and the SE and Titmus values were decreased (P<0.05) after treatment in both groups. After treatment, in the observation group, the best corrected visual acuity was higher (P<0.05), the latency of P-VEP P100 wave was shorter and the amplitude of P-VEP P100 wave was higher (P<0.05), SE and Titmus values were lower (P<0.05) than those in the control group. The total effective rate was 86.1% (31/36) in the observation group, which was superior to 65.8% (25/38) in the control group (P<0.05). CONCLUSIONS: During the visual plasticity period, Tiaoqi Tongjing Mingmu acupuncture combined with conventional treatment can effectively improve the best corrected vision, diopter and stereoacuity in children with anisometropic amblyopia, and enhance the nerve conduction function from retina to visual cortex. Its effect is superior to that of simple conventional treatment.

Psychological intervention for a person living with amblyopia: a case study from home-based integrated care.

Amblyopia is a common developmental disability resulting in reduced visual acuity and gaze stability; it occurs in approximately 5% of the general population. Here, we present the case of an 18-year-old girl diagnosed with amblyopia. Subsequent to her diagnosis of amblyopia, she developed a depressive episode with co-morbid anxiety symptoms. She was treated with low intensity psychological intervention, Problem Management Plus, as home-based intervention. This intervention was associated both subjectively and objectively utilising psychometric measures (i.e. psychiatric interview, depression, anxiety and stress scale, general health questionnaire) with a significant amelioration of her mental state. This case provides preliminary evidence for the effectiveness of Problem Management Plus intervention and suggests that this intervention should be considered for other individuals with similar clinical presentations.

Severe Adverse Events of Periocular Acupuncture: A Review of Cases.

Acupuncture is recognized as a component of alternative medicine and is increasingly used worldwide. Many studies have shown the various effects of acupuncture around the eyes for ophthalmologic or nonophthalmologic conditions. For ophthalmologic conditions, the effect of acupuncture on dry eye syndrome, glaucoma, myopia, amblyopia, ophthalmoplegia, allergic rhinoconjunctivitis, blepharospasm, and blepharoptosis has been reported. Recently, several studies on dry eye syndrome have been reported and are in the spotlight. However, given the variety of study designs and reported outcomes of periocular acupuncture, research is still inconclusive, and further studies are required. In addition, although a systematic and reliable safety assessment is required, to the best of our knowledge, there have been no reports of a literature review of ocular complications resulting from periocular acupuncture. This review collected cases of ocular injury as severe adverse events from previously published case reports of periocular acupuncture. A total of 14 case reports (15 eyes of 14 patients) of adverse events published between 1982 and 2020 were identified. This review article provides a summary of the reported cases and suggestions for the prevention and management of better visual function prognosis.

Effectiveness of binocular therapy as a complementary treatment of part-time patching in older amblyopic children: a randomized clinical trial.

PURPOSE: To assess the effectiveness of combined use of stereoscopic 3D video movies and part-time patching in treating older amblyopic children with poor response or compliance to traditional patching treatments and comparing this combined treatment with patching alone. METHODS: Thirty-two children aged 5-12 years with amblyopia associated with anisometropia, strabismus, or both were recruited in a randomized clinical trial. Eligible participants were assigned randomly to the combined and patching groups. Here, binocular treatment refers to using the Bangerter filter to blur the fellow eye and subsequently watching a close-up 3D movie with large parallax. The primary outcome was amblyopic eye (AE) best-corrected visual acuity (BCVA) improvement at six weeks. In addition, secondary outcomes included BCVA of AE improvement at three weeks and change of stereoacuity. RESULTS: Of 32 participants, mean (SD) age was 6.63 (1.46) years, and 19 (59%) were female. At 6 weeks, mean (SD) amblyopic eye VA improved by 0.17 ± 0.08 logMAR (2-sided 95% CI, 0.13 to 0.22; F = 57.2, p < 0.01) and 0.05 ± 0.04 logMAR (2-sided 95% CI, 0.05 to 0.09; F = 8.73, p = 0.01) in the combined and patching groups, respectively. The difference was statistically significant (mean difference, 0.13 logMAR [1.3 line]; 95% CI, 0.08-0.17 logMAR [0.8-1.7 lines]; t25 = 5.65, p < 0 .01). After treatment, only the combined group had significantly improved stereoacuity, such as binocular function score (median [interquartile range], 2.30 [2.23 to 2.68] vs. 1.69 [1.60 to 2.30] log arcsec; paired, z = -3.53, p < 0.01), and mean stereoacuity gain was 0.47 log arcsec (± 0.22). Changes in other types of stereoacuity were similar. CONCLUSION: Our laboratory-based binocular treatment strategy engaged a high level of compliance that led to a substantial gain in visual function after a short period of treatment for older amblyopic children having poor response or compliance to traditional patching treatments. Notably, the improving stereoacuity showed a greater advantage.

Comparison of compliance among patients with pediatric amblyopia undergoing virtual reality-based and traditional patching method training.

Introduction: This study aimed to compare compliance between pediatric patients with amblyopia undergoing a smartphone virtual reality-based training method (EYEBIT) and those receiving traditional patching method training. Methods: A crossover design was adopted in this study. The enrolled children (n = 76) were randomized into the traditional patching and EYEBIT training method groups. The patients received training methods once a day for 2 h and 1 h in the patching and EYEBIT groups, respectively. Follow-up assessments involved interviews with parents regarding children's compliance and questionnaire-based interviews with children; compliance rating was compared between the methods. Results: All children completed the training and follow-up assessments. There were significant differences in parent and children compliance-related behavior and attitudes between the two training methods (p < 0.05). The EYEBIT method was associated with better compliance than the traditional patching method. Significant correlations were observed among compliance components in both methods. In the correlation analysis between the two groups, the research results showed that in the EYEBIT group, the correlation between children's compliance behaviors and children's compliance attitudes, the correlation between children's compliance behaviors and parents' compliance behaviors, and the correlations between children's compliance attitudes and parents' compliance attitudes were all negatively correlated, and in the traditional patching group, the above three correlation analysis results were all positive. Conclusion: The use of the EYEBIT method may improve compliance in children with amblyopia; this method appears acceptable to the parents of children with amblyopia.

Unilateral advanced glaucoma in isolated congenital ectropion uveae with ipsilateral ptosis: A pictorial description of five children.

Aim: To report the cases of five children with unilateral advanced glaucoma in isolated congenital ectropion uveae (CEU) with ipsilateral ptosis and myopia. Methods: This is an ambispective observational case series. After diagnosing one patient with CEU and glaucoma, consecutive patients presenting with unilateral ptosis, congenital iris anomaly, and glaucoma between 2014 to 2020, and had completed a minimum one-year postoperative follow-up, were analyzed. Results: Of the 1421 newly registered pediatric glaucoma patients in the period under review, five children were diagnosed with CEU. All patients presented with gradual painless diminution of vision in the left eye in early adolescence. The left eye of all patients had peculiar clinical features: mild congenital ptosis, high iris insertion, crypt-less smooth iris surface, congenital ectropion uveae, pigments over anterior lens capsule, high myopia, advanced glaucomatous optic disc cupping, and very high intraocular pressure (IOP), which was > 45 mmHg in all cases. The right eye showed signs of angle dysgenesis with mild anterior iris insertion and numerous fine iris processes. Antiglaucoma medications and angle surgery failed to control the IOP, and all children required glaucoma filtration surgery, resulting in reasonable IOP control. Despite the older age, postoperative strict amblyopia treatment resulted in significant improvement in vision. Conclusions: Although ectropion uveae and ptosis have been present since birth, unilaterality, and the asymptomatic nature of the disease led to the late presentation with irreversible damage. Early surgical management and amblyopia therapy are the cornerstones of management. Abbreviations: CEU = Congenital ectropion uvea, CIES = Congenital Iris Ectropion Syndrome, ASD = Anterior segment dysgenesis syndrome, BCVA = Best-corrected visual acuity, IOP = Intraocular pressure.

Binocular treatment for amblyopia: A meta-analysis of randomized clinical trials.

BACKGROUND: To date, there is still no consensus regarding the effect of binocular treatment for amblyopia. The purpose of this systematic review and meta-analysis was to summarize the available evidence to determine whether binocular treatment is more effective than patching in children with amblyopia. METHODS: Four electronic databases (PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials) were searched for studies that compared binocular treatment and patching in children with amblyopia. The outcome measures were visual acuity and stereopsis. Pooled effects sizes were calculated with a random-effect model. The standardized difference in means (SDM) with 95% confidence intervals (CI) was calculated. Sensitivity analysis and assessment of publication bias were performed. RESULTS: Five randomized clinical trials were included. No significant difference in visual acuity between patients treated with binocular treatment and patching was observed (SDM = -0.12; 95% CI: -0.45-0.20; P = 0.464). No significant difference in stereopsis between patients treated with binocular treatment and patching was observed (SDM = -0.07; 95% CI: -0.61-0.48; P = 0.809). For both variables, the between-study heterogeneity was high (respectively, I2 = 61% and I2 = 57%). CONCLUSIONS: This meta-analysis found no convincing evidence supporting the efficacy of binocular treatment as an alternative to conventional patching. Therefore, the binocular treatment cannot fully replace traditional treatment but, to date, it can be considered a valid complementary therapy in peculiar cases. Further studies are required to determine whether more engaging therapies and new treatment protocols are more effective.

Effectiveness of citicoline in pediatric patients with refractive amblyopia in Surabaya, East Java, Indonesia.

OBJECTIVES: Amblyopia is a decrease of visual acuity that cannot be attributed to any structural abnormality of the eye or visual system, causing a partial or complete loss of vision due to inadequate stimulation in early life. Citicoline has been reported to improve visual acuity in amblyopic eyes as adjuvant treatment. This study was aimed to determine the effectiveness of citicoline in pediatric patients with refractive amblyopia in ophthalmology daily practices. METHODS: This was a retrospective-descriptive study with a time limited sampling method. This study was conducted at Surabaya Eye Clinic, East Java, Indonesia, by reviewing medical records for the period of January 2018 to December 2019. RESULTS: A total of 34 eyes were included in the study with the majority aged five years (41.2%) and six years (35.3%). The severity of amblyopia varied among patients, 21 eyes (61.76%) had mild amblyopia, seven eyes (20.59%) had moderate amblyopia, and two eyes (5.88%) had severe amblyopia. The duration of given therapy also varied, 18 eyes (52.94%) were given 3 months therapy, two eyes were given 4 months therapy, 12 eyes were given 6 months therapy, and two eyes were given 8 months therapy. Citicoline was found effective in mild and moderate amblyopia and for the duration of 3 and 6 months (p<0.05). In others group who did not showed statistically significant improvement was due to inadequate samples but clinically significant improvement was noted. CONCLUSIONS: Citicoline therapy resulted in a clinically and statistically improvement in refractive amblyopia patients.

[Observation of acupoint thread-embedding on refractive amblyopia in children].

OBJECTIVE: To observe the effect of acupoint thread-embedding on visual acuity and morphology of retina in children with refractive amblyopia. METHODS: A total of 60 children with refractive amblyopia were randomized into an observation group (30 cases, 2 cases dropped off) and a control group (30 cases, 1 case dropped off). In the control group, comprehensive therapy of eye covering of intact side and family refined performance was adopted. On the basis of the treatment in the control group, acupoint thread-embedding was applied at Ganshu (BL 18), Pishu (BL 20), Shenshu (BL 23), Zusanli (ST 36), Guangming (GB 37) in the observation group, once every 2 weeks. The treatment for 2 months was required in the both groups. The corrected vision and the variations of macular thickness of retina and average thickness of retinal nerve fiber layer (RNFL) before and after treatment were observed, and the therapeutic efficacy was evaluated in the both groups. RESULTS: After treatment, the corrected vision was increased compared before treatment in the both groups (P<0.05), and the improvement of corrected vision in the observation group was superior to that in the control group (P<0.05); the macular thickness of retina and the average thickness of RNFL were thinner compared before treatment in the both groups (P<0.05), and the macular thickness of retina and the average thickness of RNFL in the observation group were thinner than those in the control group (P<0.05). The total effective rate was 92.9% (26/28) in the observation group, which was superior to 79.3% (23/29) in the control group (P<0.05). CONCLUSION: Acupoint thread-embedding can effectively increase the corrected vision in children with refractive amblyopia, and has improvement in retina morphological damage to a certain extent.

Fixation stability after surgical treatment of strabismus and biofeedback fixation training in amblyopic eyes.

BACKGROUND: Visual fixation may be affected in amblyopic patients and, moreover, its stability may be associated with the effects of amblyopic treatments on visual performance in patients with strabismus. Therefore, fixation stability is a relevant biomarker that might predict the recurrence of amblyopia after a therapeutic intervention. Microperimetric biofeedback fixation training (BFT) can stabilize visual fixation in adult patients with central vision loss. It was the purpose of the present study to evaluate the effects of BFT on fixation stability in adult amblyopic patients after surgical intervention to treat strabismus. METHODS: Participants were 12 patients with strabismus (mean age = 29.6 ± 8.5 years; 6 females) and 12 healthy volunteers (mean age = 23.8 ± 1.5 years; 9 females). The protocol included ophthalmological and microperimetric follow-ups to measure fixation stability and macular sensitivity. BFT was applied monocularly to four amblyopic eyes either on the spontaneous preferential retinal locus or to a fixation area closer to the anatomical fovea after surgical treatment of strabismus. RESULTS: Baseline measurements showed significantly altered microperimetric average threshold in amblyopic eyes compared to fellow eyes (p = 0.024) and compared to control eyes (p < 0.001). Fixation was unstable in amblyopic eyes compared to control eyes (p < 0.001). Fixation stability did not significantly change after surgical alignment of strabismus (p = 0.805). BFT applied to operated eyes resulted in a more stable fixation with improvements of about 50% after three months of training. CONCLUSIONS: Fixation stability improvements following BFT highlight its potential use in adult amblyopic eyes after the surgical alignment of the strabismus. Future investigations may also consider applying this method in combination with standard treatments to improve vision in amblyopic patients.

Role of Acupuncture in Amblyopia Treatment.

CONTEXT: Amblyopia is an ophthalmological developmental disorder that occurs during early childhood due to disrupted binocular vision. It leads to reduced best-corrected visual acuity in one eye (seldom in both eyes) in which the visual acuity of one eye is 2 rows weaker than the other eye on a Snellen vision testing chart. Many studies have reported the outcomes of acupuncture in the treatment of amblyopia. Evidence suggests that acupuncture improves outcomes in children with amblyopia, but these studies are associated with several limitations which may affect the evaluation of the efficacy and reproducibility of studies on acupuncture. One important limitation is the lack of sham acupuncture as a control which has not been used in any clinical trial. The use of nonacupoint acupuncture is suggested as a placebo to improve the quality of evidence and comparability?

Observation of acupoint thread-embedding on refractive amblyopia in children / 中国针灸

OBJECTIVE@#To observe the effect of acupoint thread@*METHODS@#A total of 60 children with refractive amblyopia were randomized into an observation group (30 cases, 2 cases dropped off) and a control group (30 cases, 1 case dropped off). In the control group, comprehensive therapy of eye covering of intact side and family refined performance was adopted. On the basis of the treatment in the control group, acupoint thread@*RESULTS@#After treatment, the corrected vision was increased compared before treatment in the both groups (@*CONCLUSION@#Acupoint thread

Insomnia in Relation to Academic Performance, Self-Reported Health, Physical Activity, and Substance Use Among Adolescents.

PURPOSE: Insomnia affects up to one in four adolescents and has been shown to have a negative impact on their mental and physical health. This study aimed to investigate the association between insomnia, academic performance, self-reported health, physical activity, school start time, and substance use among adolescents. METHODS: A survey with a cross-sectional design was completed by adolescents (15-17 years old; n = 1504) in southern Sweden. The Minimal Insomnia Symptoms Scale (MISS) was used to operationalize insomnia. A multiple logistic regression analysis was used to analyze the relationship between insomnia and self-reported health, failed school courses, substance use, school start time, family financial situation, screen time, and gender. RESULTS: Insomnia (MISS ≥ 6) was associated with poor self-reported health (OR: 4.35), failed school courses (OR: 1.47), and use of alcohol and/or cigarettes (OR: 1.43). When the combined effect of self-reported health and physical activity were investigated, a combination of low physical activity (≤1 time/week) and poor self-reported health was strongly associated with insomnia (OR: 18.87). CONCLUSIONS: Insomnia was associated with other problems that in themselves are risk factors for poor health. This highlights the need for a holistic health-promoting approach to prevent insomnia, such as efforts to promote physical activity, school success, and the reduction of alcohol/cigarette use.

Vision training with VEP biofeedback in amblyopia after the critical period.

PURPOSE: The purpose of this study was to investigate the benefits of vision training with visual evoked potentials (VEP) biofeedback in amblyopia after the critical period in 8 to 17-year (11.5 ± 3.1) old children. METHODS: Ten participants with monocular amblyopia after the critical period underwent a 10-week, 20-session vision training program with the Retimax Vision Trainer device. During each session, the participants were instructed to be as focused as possible onto the fixation point in the middle of the screen. The size of the fixation point and the pitch of the background sound were changing according to VEP parameters and thus provided the participants real-time feedback of their visual performance. RESULTS: The mean BCVA improvement across our group was 0.12 LogMAR (p < 0.01). There was also a significant increase in contrast sensitivity to the FACT chart across all spatial frequencies (all p < 0.05). Electrophysiologic data revealed higher steady-state visual evoked potentials (SS-VEP) amplitudes and correspondingly lower fixation point values in the last 2 weeks of training compared to the first 2 weeks (both p < 0.01). Due to unexplainably low VEP amplitude levels in later trainings compared to those in the beginning in two participants, we have not found a significant correlation between the increase in BCVA and the increase in SS-VEP amplitude (p = 0.88). At the follow-up at 2 and 12 months following the end of training, both BCVA and contrast sensitivity remained within the levels achieved at the end of training. In some participants, however, no improvement of BCVA was observed. CONCLUSIONS: The tested vision training approach demonstrates modest but stable improvement of psychophysical parameters as well as objective characteristics in amblyopia after the critical period. Real-time SS-VEP can be used as an objective parameter to monitor participants' attention during vision training stimulation.

Long-term Monocular Deprivation during Juvenile Critical Period Disrupts Binocular Integration in Mouse Visual Thalamus.

Study of the neural deficits caused by mismatched binocular vision in early childhood has predominantly focused on circuits in the primary visual cortex (V1). Recent evidence has revealed that neurons in mouse dorsolateral geniculate nucleus (dLGN) can undergo rapid ocular dominance plasticity following monocular deprivation (MD). It remains unclear, however, whether the long-lasting deficits attributed to MD during the critical period originate in the thalamus. Using in vivo two-photon Ca2+ imaging of dLGN afferents in superficial layers of V1 in female and male mice, we demonstrate that 14 d MD during the critical period leads to a chronic loss of binocular dLGN inputs while sparing response strength and spatial acuity. Importantly, MD leads to profoundly mismatched visual tuning properties in remaining binocular dLGN afferents. Furthermore, MD impairs binocular modulation, reducing facilitation of responses of both binocular and monocular dLGN inputs during binocular viewing. As predicted by our findings in thalamic inputs, Ca2+ imaging from V1 neurons revealed spared spatial acuity but impaired binocularity in L4 neurons. V1 L2/3 neurons in contrast displayed deficits in both binocularity and spatial acuity. Our data demonstrate that critical-period MD produces long-lasting disruptions in binocular integration beginning in early binocular circuits in dLGN, whereas spatial acuity deficits first arise from circuits further downstream in V1. Our findings indicate that the development of normal binocular vision and spatial acuity depend upon experience-dependent refinement of distinct stages in the mammalian visual system.SIGNIFICANCE STATEMENT Abnormal binocular vision and reduced acuity are hallmarks of amblyopia, a disorder that affects 2%-5% of the population. It is widely thought that the neural deficits underlying amblyopia begin in the circuits of primary visual cortex. Using in vivo two-photon calcium imaging of thalamocortical axons in mice, we show that depriving one eye of input during a critical period in development chronically impairs binocular integration in thalamic inputs to primary visual cortex. In contrast, visual acuity is spared in thalamic inputs. These findings shed new light on the role for developmental mechanisms in the thalamus in establishing binocular vision and may have critical implications for amblyopia.

17α Estradiol promotes plasticity of spared inputs in the adult amblyopic visual cortex.

The promotion of structural and functional plasticity by estrogens is a promising approach to enhance central nervous system function in the aged. However, how the sensitivity to estrogens is regulated across brain regions, age and experience is poorly understood. To ask if estradiol treatment impacts structural and functional plasticity in sensory cortices, we examined the acute effect of 17α-Estradiol in adult Long Evans rats following chronic monocular deprivation, a manipulation that reduces the strength and selectivity of deprived eye vision. Chronic monocular deprivation decreased thalamic input from the deprived eye to the binocular visual cortex and accelerated short-term depression of the deprived eye pathway, but did not change the density of excitatory synapses in primary visual cortex. Importantly, we found that the classical estrogen receptors ERα and ERß were robustly expressed in the adult visual cortex, and that a single dose of 17α-Estradiol reduced the expression of the calcium-binding protein parvalbumin, decreased the integrity of the extracellular matrix and increased the size of excitatory postsynaptic densities. Furthermore, 17α-Estradiol enhanced experience-dependent plasticity in the amblyopic visual cortex, by promoting response potentiation of the pathway served by the non-deprived eye. The promotion of plasticity at synapses serving the non-deprived eye may reflect selectivity for synapses with an initially low probability of neurotransmitter release, and may inform strategies to remap spared inputs around a scotoma or a cortical infarct.

Simplified updates on the pathophysiology and recent developments in the treatment of amblyopia: A review.

Amblyopia is the most common cause of monocular visual impairment affecting 2-5% of the general population. Amblyopia is a developmental cortical disorder of the visual pathway essentially due to abnormal visual stimulus, reaching the binocular cortical cells, which may be multivariate. Ganglion cells are of two types: parvocellular (P cells) and magnocellular (M cells); they are the first step where the light energy is converted in to neural impulse. P cells are involved in fine visual acuity, fine stereopsis, and color vision and M cells are involved in gross stereopsis and movement recognition. Strabismus, refractive error, cataract, and ptosis, occurring during critical period are highly amblyogenic. The critical period extends from birth to 7--8 years. The earlier the clinically significant refractive error and strabismus are detected and treated, the greater the likelihood of preventing amblyopia. Treatment for amblyopia in children includes: optical correction of significant refractive errors, patching, pharmacological treatment, and alternative therapies which include: vision therapy, binocular therapy, and liquid crystal display eyeglasses are newer treatment modalities for amblyopia. Age of starting the treatment is not predictive of outcome, instituting treatment on detection and early detection plays a role in achieving better outcomes. This review aims to give a simplified update on amblyopia, which will be of use to a clinician, in understanding the pathophysiology of the complex condition. We also share the cortical aspects of amblyopia and give recent developments in the treatment of amblyopia.

Amblyopia Affects the ON Visual Pathway More than the OFF.

Visual information reaches the cerebral cortex through parallel ON and OFF pathways that signal the presence of light and dark stimuli in visual scenes. We have previously demonstrated that optical blur reduces visual salience more for light than dark stimuli because it removes the high spatial frequencies from the stimulus, and low spatial frequencies drive weaker ON than OFF cortical responses. Therefore, we hypothesized that sustained optical blur during brain development should weaken ON cortical pathways more than OFF, increasing the dominance of darks in visual perception. Here we provide support for this hypothesis in humans with anisometropic amblyopia who suffered sustained optical blur early after birth in one of the eyes. In addition, we show that the dark dominance in visual perception also increases in strabismic amblyopes that have their vision to high spatial frequencies reduced by mechanisms not associated with optical blur. Together, we show that amblyopia increases visual dark dominance by 3-10 times and that the increase in dark dominance is strongly correlated with amblyopia severity. These results can be replicated with a computational model that uses greater luminance/response saturation in ON than OFF pathways and, as a consequence, reduces more ON than OFF cortical responses to stimuli with low spatial frequencies. We conclude that amblyopia affects the ON cortical pathway more than the OFF, a finding that could have implications for future amblyopia treatments.SIGNIFICANCE STATEMENT Amblyopia is a loss of vision that affects 2-5% of children across the world and originates from a deficit in visual cortical circuitry. Current models assume that amblyopia affects similarly ON and OFF visual pathways, which signal light and dark features in visual scenes. Against this current belief, here we demonstrate that amblyopia affects the ON visual pathway more than the OFF, a finding that could have implications for new amblyopia treatments targeted at strengthening a weak ON visual pathway.

Impaired Spatial Hearing in Amblyopia: Evidence for Calibration of Auditory Maps by Retinocollicular Input in Humans.

Purpose: Evidence from animals and blind humans suggests that early visual experience influences the developmental calibration of auditory localization. Hypothesizing that unilateral amblyopia may involve cross-modal deficits in spatial hearing, we measured the precision and accuracy of sound localization in humans with amblyopia. Methods: All participants passed a standard hearing test. Experiment 1 measured sound localization precision for click stimuli in 10 adults with amblyopia and 10 controls using a minimum audible angle (MAA) task. Experiment 2 measured sound localization error (i.e., accuracy) for click train stimuli in 14 adults with amblyopia and 16 controls using an absolute sound localization task. Results: In Experiment 1, the MAA (mean ± SEM) was significantly greater in the amblyopia group compared with controls (2.75 ± 0.30° vs. 1.69 ± 0.09°, P = 0.006). In Experiment 2, the overall sound localization error was significantly greater in the amblyopia group compared with controls (P = 0.047). The amblyopia group also showed significantly greater sound localization error in the auditory hemispace ipsilateral to the amblyopic eye (P = 0.036). At a location within this auditory hemispace, the magnitude of sound localization error correlated significantly with deficits in stereo acuity (P = 0.036). Conclusions: The precision and accuracy of sound localization are impaired in unilateral amblyopia. The asymmetric pattern of sound localization error suggests that amblyopic vision may interfere with the development of spatial hearing via the retinocollicular pathway.