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Frontiers in Neuroscience 2024Cell signaling based on homeoprotein transfer is a pathway with developmental and physiological functions. For a few transcription factors of this family, primarily... (Review)
Review
Cell signaling based on homeoprotein transfer is a pathway with developmental and physiological functions. For a few transcription factors of this family, primarily ENGRAILED1, ENGRAILED2 and OTX2, their physiological functions have led to therapeutic strategies in animal models of human diseases, including Parkinson's disease, amyotrophic lateral sclerosis, amblyopia and anxiety-related disorders. In mesencephalic dopaminergic neurons which degenerate in Parkinson's disease, ENGRAILED1/2 have cell autonomous activities, but their transducing properties enables their use as therapeutic proteins. In contrast, in spinal alpha-motoneurons, which are lost in amyotrophic lateral sclerosis, ENGRAILED1 is supplied by V1 interneurons. Thus, its use as a therapeutic protein to protect alpha-motoneurons against degeneration mimics its normal non-cell autonomous neurotrophic activity. OTX2, synthesized and secreted by the choroid plexus, is transferred to parvalbumin interneurons and exerts regulatory functions controlling cerebral cortex plasticity. Understanding the latter OTX2 function has led to strategies for manipulating visual acuity and anxiety-like behavior in adult mice. In this review, we describe these cases and what is known about the involved molecular mechanisms. Because the transduction sequences are conserved in most of the few hundred homeoproteins, we argue how this family of molecules constitutes an important reservoir of physiological knowledge, with potential consequences in the search for new therapeutic strategies.
PubMed: 38550565
DOI: 10.3389/fnins.2024.1359523 -
Journal of Clinical Medicine Mar 2024The ability to merge the two retinal images to perceive depth (stereopsis) plays an important role in human vision. Its proper development requires binocular alignment...
The ability to merge the two retinal images to perceive depth (stereopsis) plays an important role in human vision. Its proper development requires binocular alignment and good visual acuity in both eyes during childhood. Because treatments are more effective when applied early, early diagnosis is important. Unfortunately, assessing stereo deficiencies in infants and young children remains challenging. Recently, it has been shown that ocular-following responses (OFRs; reflexive, short-latency eye movements induced by the sudden motion of a large textured pattern) are sensitive to changes in interocular correlation, making them potentially useful for stereo deficiency assessments. To test this hypothesis, we measured OFRs elicited by dichoptic stimulation in children with normal and compromised stereopsis (due to amblyopia). Two groups of six children (age- and sex-matched: 3M/3F aged 7-12 yo), one with compromised stereopsis and one with normal stereopsis, were included. OFRs were recorded using a custom high-resolution video eye-tracking system. The relative differences between eye displacement induced by correlated stimuli (up-correlated-down-correlated) and anticorrelated (up-anticorrelated-down-anticorrelated) were compared. We found significant differences between OFRs induced by two dichoptic conditions (correlated and anticorrelated stimuli) in most children with normal stereopsis, whereas no differences were observed in children with compromised stereopsis, indicating a lack of disparity detectors. OFRs might thus be exploited as a diagnostic tool for the objective identification of stereo deficiencies in children. This might lead to improved early diagnosis and treatment outcomes for conditions like amblyopia and strabismus.
PubMed: 38541822
DOI: 10.3390/jcm13061596 -
Therapeutic Advances in Ophthalmology 2024Pediatric corneal transplant is a highly demanding and technically challenging procedure for the cornea surgeon in today's era. These cases pose unique challenges in... (Review)
Review
Pediatric corneal transplant is a highly demanding and technically challenging procedure for the cornea surgeon in today's era. These cases pose unique challenges in clinical and surgical management. The indications of pediatric corneal transplant can be therapeutic, tectonic, optical, and cosmetic. Pediatric patients undergoing corneal transplants are at a high risk of graft infection, failure, rejection, dehiscence, and amblyopia due to young age, robust immune system, increased incidence of trauma, and compliance issues. The other factors contributing to graft failure can be allograft rejection, secondary glaucoma, corneal vascularization, multiple surgeries, vitreous prolapse, and lack of treatment compliance. A successful corneal transplant in children depends on meticulous preoperative evaluation, uneventful surgery, the expertise of a corneal surgeon, and regular and timely postoperative follow-up. Therapeutic and optical penetrating keratoplasty are the most commonly performed transplants in children. However, with the advancements in surgical technique and management protocol, the current focus has shifted toward lamellar keratoplasty. Lamellar keratoplasty offers early visual recovery and potentially fewer complications. Visual rehabilitation through corneal transplant in otherwise blind eyes can be a boon for the children. Recently, keratoprostheses have been promising in children with multiple graft failures. The current review gives insights into epidemiology, etiology, indications, clinical characteristics, investigations, management options, recent advances, and the future of pediatric corneal transplants. As surgical techniques continue to grow and comprehension of pediatric corneal transplants is improving, we can safeguard these eyes with the best possible anatomical and functional outcomes.
PubMed: 38533487
DOI: 10.1177/25158414241237906 -
Investigative Ophthalmology & Visual... Mar 2024This study aimed to evaluate the effects of monocular flicker stimulation on binocular imbalance in both amblyopic and nonamblyopic adults.
PURPOSE
This study aimed to evaluate the effects of monocular flicker stimulation on binocular imbalance in both amblyopic and nonamblyopic adults.
METHODS
Seven amblyopic patients (28.3 ± 3.3 years; four females) and seven normally sighted participants (27.3 ± 4.1 years; five females) participated in the study. We used liquid crystal spectacles to create externally-generated monocular flicker (4, 7, 10, 15, or 20 Hz) and used the metric of log balance point (logBP) to determine whether imposed flicker could change the eyes' equilibrium interocular contrast ratio. Flicker was applied to either the fellow eye vs. the amblyopic eye or dominant eye (DE) vs. non-DE (non-DE) of amblyopic and nonamblyopic participants, respectively. We defined a logBP of 0 to indicate complete binocular balance and an increase in logBP relative to baseline to indicate a relative strengthening of the non-DE or amblyopic eye.
RESULTS
Monocular flicker applied to the DE or fellow eye increased logBP, whereas when applied to the non-DE or amblyopic eye, reduced the logBP. These effects were more pronounced at low temporal frequencies than that at high temporal frequencies. The interaction between eye and temporal frequency was significant in both normals, F(4, 24) = 58.082, P < 0.001, η2 = 0.906, and amblyopes, F(1.923, 11.538) = 60.555, P < 0.001, η2 = 0.91.
CONCLUSIONS
Monocular flicker diminishes the contribution of the flickered eye in binocular combination, resulting in a relative dominance of the nonflickered eye in interocular interactions. Furthermore, a more pronounced temporally modulated effect was observed at lower temporal frequencies.
Topics: Adult; Female; Animals; Humans; Amblyopia; Birds
PubMed: 38530301
DOI: 10.1167/iovs.65.3.33 -
Journal of Pediatric Ophthalmology and... 2024
Topics: Child; Humans; Amblyopia
PubMed: 38529748
DOI: 10.3928/01913913-20240124-01 -
Oman Journal of Ophthalmology 2024
PubMed: 38524343
DOI: 10.4103/ojo.ojo_28_24 -
Oman Journal of Ophthalmology 2024Purpose was to determine the prevalence of amblyopia and its related risk factors in children aged 3-6 years in Bojnurd, north-eastern Iran.
BACKGROUND
Purpose was to determine the prevalence of amblyopia and its related risk factors in children aged 3-6 years in Bojnurd, north-eastern Iran.
MATERIALS AND METHODS
In this cross-sectional study, from 12,331 children aged 3-6 in Bojnurd, 6600 children participated in annual amblyopic screening program and among them, around 1100 suspected cases were referred for full ophthalmic examinations. Measurement of visual acuity, cycloplegic refraction, subjective refraction, and cover test were performed for all participants. Amblyopia was defined as CDVA of 0.2 LogMar or less in each eye or 2-line difference or more in best-corrected visual acuity between two eyes.
RESULTS
The prevalence of amblyopia was estimated 0.95% (95% confidence interval [CI]: 0.73%-1.2%). There was no relationship between amblyopia with age and genders. Most amblyopic children were hyperopic (61.9%; 95% CI: 48.7-73.8). Strabismus was found in 17.4% of amblyopic patients (95% CI: 9.05%-29.09%). Approximately half of the amblyopic children were anisometropic (55.5%; 95% CI: 42.40%-68.08%). The most common type of amblyopia was anisohyperopic (55.56%; 95% CI: 42.5%-67.5%). The prevalence of bilateral amblyopia was more than unilateral amblyopia. The assessment of data showed that hyperopia, astigmatism, and anisometropia were the most common causes of amblyopia in this study.
CONCLUSIONS
The prevalence of amblyopia was estimated about 1% in north-eastern Iran. Our study indicated a valuable information around the effect of refractive error and anisometropia on amblyopia which could be helpful in designing a comprehensive vision screening program for preschool children.
PubMed: 38524325
DOI: 10.4103/ojo.ojo_295_22 -
Beyoglu Eye Journal 2024The objective of the study is to evaluate the examination findings, treatment methods, and follow-up results of children diagnosed with infantile esotropia (IE) and to...
OBJECTIVES
The objective of the study is to evaluate the examination findings, treatment methods, and follow-up results of children diagnosed with infantile esotropia (IE) and to compare botulinum toxin A (BTA) and bilateral medial rectus (MR) recession surgery.
METHODS
We retrospectively reviewed the medical records of patients who were diagnosed with IE. The age of the patient and the angle of deviation were taken into account to determine the treatment. Patients who underwent bilateral MR recession surgery and BTA injection were analyzed and the BTA and surgical groups were compared. Successful correction was defined as orthotropia and a deviation of up to 10 prism diopters (PD) after one surgical procedure or 1-3 botulinum injections.
RESULTS
Two hundred and forty-six patients with esotropia were included in the study. Twelve were followed up with refractive correction only. BTA injection was administered to 110 patients, while 124 patients underwent bilateral MR recession. The age of the patients ranged from three to 39 months. Patients were followed for at least 6 months, with a mean follow-up of 24.3 months in the BTA group and 21.7 months in the surgical group (p=0.23). The mean pre-treatment angle deviation was 38.9 PD in the BTA group and 40.1 PD in the surgical group (p=0.62). The success rate for patients with more than 30 PD of deviation was 72% in the surgical group compared to 36% in the BTA group (p<0.001). No statistically significant difference in success rate was observed in patients with deviations <30 PD (surgery 62%, BTA 55%, p=0.26).
CONCLUSION
Surgical treatment of IE was more successful than BTA injection in patients with large angle deviations (>30 PD). BTA injection can be considered as an alternative to surgery in cases of small to moderate angle deviations (<30 PD).
PubMed: 38504960
DOI: 10.14744/bej.2024.90958 -
Clinical Optometry 2024To be successful, amblyopia therapeutic techniques must respond when ingenious (shrewd) amblyopic children sabotage treatment effect by discovering ways(1) to alter...
BACKGROUND
To be successful, amblyopia therapeutic techniques must respond when ingenious (shrewd) amblyopic children sabotage treatment effect by discovering ways(1) to alter those therapy aspects they find frustrating.
METHODS
Her guardian consented to IRB-approved study outside typical FDA enrollment guidelines for CureSight dichoptic therapy. Acuity (EVA) and stereopsis was by PEDIG protocols.
RESULTS
A 6-year-old rural Alaska native girl in foster care had previously been diagnosed with anisometropic amblyopia and treated with spectacles and patching but had poor compliance with BCVA 0.9-1.0 logMAR. She demonstrated exceptional creativity and hyperactivity but had no other medical issues. Atropine was prescribed in addition to her spectacles +5.50+1.00x90 and +0.50+1.00x90, but the patient discovered the rare "Spectacle Flip" method that sabotaged therapeutic impact. She had EVA enrollment acuities of logMAR 0.9 right and -0.1 left with stereo 400 seconds of arc. After just one month dichoptic therapy 1.5 hours 6 days per week, acuity improved to logMAR 0.7 and -0.1 with stereo up to 140 second of arc. Four months later acuity was 0.6 right and -0.2 left. Stereoacuity improved from 400 to 200 arc seconds.
CONCLUSION
Even when conventional compliance methods fail, dichoptic therapy with eye-tracking has the novel and unique potential to improve amblyopia treatment compliance with real-time monitored fixation compliance and confirmation of correct spectacle wear.
CLINICAL TRIAL REGISTRATION
NCT06165705.
PubMed: 38476961
DOI: 10.2147/OPTO.S454342 -
Investigative Ophthalmology & Visual... Mar 2024Amblyopic and strabismus subjects experience inter-ocular suppression, impaired stereoacuity, and increased fixation instability. The purpose of the study was to...
PURPOSE
Amblyopic and strabismus subjects experience inter-ocular suppression, impaired stereoacuity, and increased fixation instability. The purpose of the study was to investigate factors affecting suppression and stereoacuity and examine their relationship to fixation eye movement (FEM) abnormalities.
METHODS
We recruited 14 controls and 46 amblyopic subjects (anisometropic = 18, strabismic = 14, and mixed = 14) and 11 subjects with strabismus without amblyopia. We utilized the dichoptic motion coherence test to quantify suppression, and stereoacuity was assessed using the Titmus Fly test. We recorded FEMs using high-resolution video-oculography and classified subjects that did not have nystagmus (n = 27) versus those with nystagmus (n = 32; fusion maldevelopment nystagmus [FMN], n = 10) and nystagmus that did not meet the criteria of FMN (n = 20). We also recorded FEMs under dichoptic viewing (DcV) at varied fellow eye (FE) contrasts and computed the amplitude and velocity of the fast and slow FEMs and vergence instability.
RESULTS
Inter-ocular suppression and stereoacuity deficits were closely correlated with an amblyopic eye (AE), visual acuity, and strabismus angle. Subjects with nystagmus displayed more pronounced stereoacuity deficits than those without nystagmus. Strabismic subjects with and without amblyopia, who demonstrated a fixation switch at 100% FE contrast, had lower inter-ocular suppression than subjects lacking a fixation switch under DcV. Amplitude of fast FEMs and velocity of slow FEMs, and vergence instability were increased as the FE contrast was lowered in both amblyopic and strabismic subjects.
CONCLUSIONS
The current study highlights the intricate relationships between AE visual acuity, eye deviation, and FEM abnormalities on suppression and stereoacuity deficits and underscores the need to evaluate FEM abnormalities while assessing dichoptic treatment outcomes.
Topics: Humans; Amblyopia; Eye Movements; Eye; Strabismus; Visual Acuity
PubMed: 38470326
DOI: 10.1167/iovs.65.3.19