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1.
JAMA Ophthalmol ; 142(1): 39-47, 2024 Jan 01.
Article in English | MEDLINE | ID: mdl-38127333

ABSTRACT

Importance: Pediatric blepharokeratoconjunctivitis (PBKC) is a chronic, sight-threatening inflammatory ocular surface disease. Due to the lack of unified terminology and diagnostic criteria, nonspecific symptoms and signs, and the challenge of differentiation from similar ocular surface disorders, PBKC may be frequently unrecognized or diagnosed late. Objective: To establish a consensus on the nomenclature, definition, and diagnostic criteria of PBKC. Design, Setting, and Participants: This quality improvement study used expert panel and agreement applying the non-RAND modified Delphi method and open discussions to identify unified nomenclature, definition, and definitive diagnostic criteria for PBKC. The study was conducted between September 1, 2021, and August 14, 2022. Consensus activities were carried out through electronic surveys via email and online virtual meetings. Results: Of 16 expert international panelists (pediatric ophthalmologists or cornea and external diseases specialists) chosen by specific inclusion criteria, including their contribution to scientific leadership and research in PBKC, 14 (87.5%) participated in the consensus. The name proposed was "pediatric blepharokeratoconjunctivitis," and the agreed-on definition was "Pediatric blepharokeratoconjunctivitis is a frequently underdiagnosed, sight-threatening, chronic, and recurrent inflammatory eyelid margin disease associated with ocular surface involvement affecting children and adolescents. Its clinical spectrum includes chronic blepharitis, meibomitis, conjunctivitis, and corneal involvement ranging from superficial punctate keratitis to corneal infiltrates with vascularization and scarring." The diagnostic criteria included 1 or more suggestive symptoms accompanied by clinical signs from 3 anatomical regions: the eyelid margin, conjunctiva, and cornea. For PBKC suspect, the same criteria were included except for corneal involvement. Conclusions and Relevance: The agreements on the name, definition, and proposed diagnostic criteria of PBKC may help ophthalmologists avoid diagnostic confusion and recognize the disease early to establish adequate therapy and avoid sight-threatening complications. The diagnostic criteria rely on published evidence, analysis of simulated clinical cases, and the expert panel's clinical experience, requiring further validation with real patient data analysis.


Subject(s)
Blepharitis , Keratoconjunctivitis , Adolescent , Child , Humans , Keratoconjunctivitis/diagnosis , Keratoconjunctivitis/complications , Keratoconjunctivitis/drug therapy , Blepharitis/diagnosis , Blepharitis/drug therapy , Eyelids , Conjunctiva , Cornea , Chronic Disease
2.
Acta Ophthalmol ; 101(2): e197-e204, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36151755

ABSTRACT

PURPOSE: To explore the effects of cyclosporine A (CsA) in the management of atopic keratoconjunctivitis (AKC). METHODS: Open single-group interventional consecutive cohort study (case series) at a single eye care facility in the UK. We reviewed the electronic patient records of 99 children and young people (CYP) aged 3.4-18 years with AKC treated with topical CsA 1 mg/ml. Main outcome measures were number of prescriptions and hospital clinic visits over 12 months before and after the start of CsA and the proportion of CYP affected by adverse effects. RESULTS: The median number of inflammatory episodes requiring treatment with topical corticosteroids (tCS) fell from 3 (interquartile range IQR 1-4) during the 12 months prior to CsA to 1 (IQR 0-3) during the 12 months after, excluding tCS prescriptions with the first CsA prescription (Wilcoxon signed ranks test, 2 tailed, p < 0.01). In the 12-month period following initiation of CsA 1 mg/ml with concomitant prescription of tCS (n = 66), daily dosage of steroids was reduced in 62 CYP (93.9%), and they were discontinued in 43 (65.2%). The median number of hospital visits fell from 4 (IQR 3-6) to 3 (IQR 2-5; Wilcoxon p < 0.01). Adverse events leading to discontinuation of CsA were stinging (instillation site pain; 9/99, 9%) and a transient skin rash (1/99, 1%). CONCLUSIONS: Off-label use of commercial preparations of CsA 1 mg/ml significantly reduces the need for concomitant topical corticosteroids and hospital clinic visits in CYP with AKC. Stinging and skin rash can lead to discontinuation.


Subject(s)
Conjunctivitis, Allergic , Exanthema , Keratoconjunctivitis , Humans , Child , Adolescent , Cyclosporine , Immunosuppressive Agents/therapeutic use , Cohort Studies , Administration, Topical , Keratoconjunctivitis/diagnosis , Keratoconjunctivitis/drug therapy , Conjunctivitis, Allergic/diagnosis , Conjunctivitis, Allergic/drug therapy , Glucocorticoids , Ophthalmic Solutions/therapeutic use , Exanthema/chemically induced , Exanthema/drug therapy , Treatment Outcome
3.
J Vis ; 22(6): 3, 2022 05 03.
Article in English | MEDLINE | ID: mdl-35506917

ABSTRACT

Visual crowding is the disruptive effect of clutter on object recognition. Although most prominent in adult peripheral vision, crowding also disrupts foveal vision in typically developing children and those with strabismic amblyopia. Do these crowding effects share the same mechanism? Here we exploit observations that crowded errors in peripheral vision are not random: Target objects appear either averaged with the flankers (assimilation) or replaced by them (substitution). If amblyopic and developmental crowding share the same mechanism, then their errors should be similarly systematic. We tested foveal vision in children aged 3 to 8 years with typical vision or strabismic amblyopia and peripheral vision in typical adults. The perceptual effects of crowding were measured by requiring observers to adjust a reference stimulus to match the perceived orientation of a target "Vac-Man" element. When the target was surrounded by flankers that differed by ± 30°, all three groups (adults and children with typical or amblyopic vision) reported orientations between the target and flankers (assimilation). Errors were reduced with ± 90° differences but primarily matched the flanker orientation (substitution) when they did occur. A population pooling model of crowding successfully simulated this pattern of errors in all three groups. We conclude that the perceptual effects of amblyopic and developing crowding are systematic and resemble the near periphery in adults, suggesting a common underlying mechanism.


Subject(s)
Amblyopia , Adult , Child , Crowding , Fovea Centralis , Humans , Pattern Recognition, Visual , Vision, Ocular , Visual Perception
5.
J Vis ; 21(13): 9, 2021 12 01.
Article in English | MEDLINE | ID: mdl-34935877

ABSTRACT

Idiopathic infantile nystagmus syndrome is a disorder characterised by involuntary eye movements, which leads to decreased acuity and visual function. One such function is visual crowding - a process whereby objects that are easily recognised in isolation become impaired by nearby flankers. Crowding typically occurs in the peripheral visual field, although elevations in foveal vision have been reported in congenital nystagmus, similar to those found with amblyopia. Here, we examine whether elevated foveal crowding with nystagmus is driven by similar mechanisms to those of amblyopia - long-term neural changes associated with a sensory deficit - or by the momentary displacement of the stimulus through nystagmus eye movements. A Landolt-C orientation identification task was used to measure threshold gap sizes with and without either horizontally or vertically placed Landolt-C flankers. We assume that a sensory deficit should give equivalent crowding in these two dimensions, whereas an origin in eye movements should give stronger crowding with horizontal flankers given the predominantly horizontal eye movements of nystagmus. We observe elevations in nystagmic crowding that are above crowding in typical vision but below that of amblyopia. Consistent with an origin in eye movements, elevations were stronger with horizontal than vertical flankers in nystagmus, but not in typical or amblyopic vision. We further demonstrate the same horizontal elongation in typical vision with stimulus movement that simulates nystagmus. Consequently, we propose that the origin of nystagmic crowding lies in the eye movements, either through image smear of the target and flanker elements or through relocation of the stimulus into the peripheral retina.


Subject(s)
Nystagmus, Congenital , Crowding , Eye Movements , Genetic Diseases, X-Linked , Humans , Visual Fields
7.
Eur J Pediatr ; 179(10): 1603-1607, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32367329

ABSTRACT

The aim of this study is to evaluate current anaesthetic practice for retinopathy of prematurity (ROP) interventions in the UK. We collected the data from the 12-month prospective British Ophthalmic Surveillance Unit study carried out in 2013/2014 that were analysed with regard to type of anaesthesia used for primary ROP procedures and the hospital department in which treatment took place. A total of 327 cases of treated ROP from 55 different UK units were reported in the study. Type of anaesthesia used during treatment was available for 324 (99.1%) cases and the treatment location in 316 (96.6%). Overall, 266 (89.3%) laser treatments and 13 (50.0%) of primary intravitreal injections were performed with the neonate intubated, using intravenous sedation (IVS) in 158 (59.4%) and the remainder, under general anaesthesia (GA). Two hundred thirteen (67.4%) of all ROP procedures took place in the neonatal unit. GA was used in 98 (95.1%) of theatre cases compared with 19 (8.9%) of cases treated in the neonatal unit. Three (0.9%) neonates suffered significant respiratory distress during or immediately after laser treatment.Conclusion: This survey suggests that the preference in UK units is to undertake ROP laser treatment in the neonatal unit with the neonate intubated and sedated intravenously. Those babies treated in the operating theatre are more likely to receive GA. In the surveyed year, half of the neonates receiving intravitreal injections as sole primary therapy was intubated; the reason for this could not be elucidated from the responses. Adverse respiratory reactions during or after laser treatment affected fewer than 1% of the neonates in this study. What is Known: • Prior to the introduction of intravitreal anti-VEGF, almost all ROP treatments in the UK were performed under general anaesthetic (GA). • The technique of intravitreal injection is described using topical anaesthesia and was thought to be changing anaesthesia preferences for ROP treatment. What is New: • Half of the neonates receiving primary anti-VEGF injection in the UK were treated under intravenous sedation or GA. • The increasing use of primary anti-VEGF treatment has not influenced trends in anaesthetic practice in the UK since the last review 10 years ago.


Subject(s)
Anesthetics , Retinopathy of Prematurity , Anesthesia, Local , Gestational Age , Humans , Infant , Infant, Newborn , Prospective Studies , Retinopathy of Prematurity/epidemiology , Retinopathy of Prematurity/therapy , United Kingdom/epidemiology
8.
Eur J Ophthalmol ; 30(5): 856-866, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31668084

ABSTRACT

Topical steroids may induce a rise in intraocular pressure. The risk may increase with prolonged use, high frequency of administration, young age, higher ocular penetrance and higher anti-inflammatory potency. We aimed to study this relationship by comparing published rates of intraocular pressure elevation following administration of topical steroids and compared the risk of higher versus lower dosage regimes, high- versus low-potency/penetration steroids and adults versus children. Data sources used were Ovid Embase, Ovid Medline, the Cochrane Central Register of Controlled Trials, Web of Science, Scopus, CINHAL Plus and LILACS. Eligible studies were randomised controlled trials of topical steroids versus any other topical steroid, nonsteroidal anti-inflammatory drugs, placebo or vehicle, or a different mode of administration administered for 7 days or longer that reported intraocular pressure elevation from baseline as >10, 6-15 or >15 mm Hg in adults or children. Risks of bias were reviewed using the GRADE quality approach. Data were extracted into the software package, RevMan, Version 5 (Cochrane Collaboration). In total, 43 studies were included. Meta-analysis was not possible. Topical steroids of lower anti-inflammatory potency, and with reduced intraocular penetration, are associated with reduced incidence of intraocular pressure elevation. A comparison of data in children and adults is limited by the use of different reporting systems. The principal obstacle to meta-analysis is the different reporting systems used to categorise intraocular pressure elevation. We recommend future studies should report intraocular pressure elevation >10 mm Hg from baseline to allow meta-analysis of data.


Subject(s)
Glaucoma/drug therapy , Glucocorticoids/adverse effects , Intraocular Pressure/drug effects , Ocular Hypertension/chemically induced , Administration, Ophthalmic , Adolescent , Adult , Child , Child, Preschool , Glucocorticoids/administration & dosage , Humans , Infant , Infant, Newborn , Ophthalmic Solutions , Risk Factors
9.
Invest Ophthalmol Vis Sci ; 60(13): 4388-4396, 2019 10 01.
Article in English | MEDLINE | ID: mdl-31634396

ABSTRACT

Purpose: To explore the impact of childhood lensectomy on posterior segment development. Methods: Cross-sectional observational study at children's eye clinics at a tertiary referral center in London, UK. We included 45 children age 4 to 16 years with healthy eyes and 38 who had undergone lensectomy. We acquired posterior segment optical coherence tomography scans of both eyes. We used parametric and nonparametric tests in SPSS24 for the comparison of parameters between groups and within individuals; a P value less than 0.05 was considered significant. The main outcome measures were foveal pit depth and subfoveal choroidal thickness (CT). Secondary outcomes were inner and outer ring CT and photoreceptor layer parameters, macular and peripapillary retinal nerve fiber layer thickness. Results: Foveal pit depth and subfoveal CT are significantly reduced in eyes that have undergone lensectomy compared with nonoperated eyes. Inner ring CT and outer ring CT are reduced. Foveal inner retinal layer thickness is increased. Mean inner retinal and outer nuclear layer thickness are not affected. Conclusions: Childhood lensectomy is associated with a reduction in developmental foveal pit deepening and lack of developmental thickening of the posterior choroid. Mechanical and optical disruption of foveal and subfoveal choroidal development may affect structural foveal development after childhood lensectomy.


Subject(s)
Cataract Extraction , Cataract/congenital , Choroid/growth & development , Fovea Centralis/growth & development , Posterior Eye Segment/growth & development , Adolescent , Child , Child, Preschool , Choroid/diagnostic imaging , Choroid/pathology , Cross-Sectional Studies , Female , Fovea Centralis/diagnostic imaging , Fovea Centralis/pathology , Humans , Male , Nerve Fibers/pathology , Photoreceptor Cells, Vertebrate/pathology , Posterior Eye Segment/diagnostic imaging , Retinal Ganglion Cells/pathology , Tomography, Optical Coherence/methods , Visual Acuity/physiology
10.
Ophthalmology ; 126(2): 233-241, 2019 02.
Article in English | MEDLINE | ID: mdl-30172708

ABSTRACT

PURPOSE: To compare Schlemm canal (SC) and trabecular meshwork (TM) in children with healthy eyes and those with and without glaucoma after lensectomy. DESIGN: Cross-sectional observational study. PARTICIPANTS: Fifty children 4 to 16 years of age with healthy eyes and 48 children who underwent lensectomy (124 healthy and 72 postlensectomy eyes). METHODS: Anterior segment (AS) OCT (Tomey SS-1000 CASIA; Tomey, Nagoya, Japan) of the nasal iridocorneal angle at 2 levels of accommodative effort (2.5 diopters [D] and 15 D). For each parameter and state of accommodation, a random effects model was fitted to estimate differences between healthy eyes and eyes with history of lensectomy. MAIN OUTCOME MEASURES: Dimensions of SC and TM and conventional AS OCT iridocorneal angle measurements. RESULTS: The horizontal diameter of SC and its cross-sectional area (CSA) are significantly smaller in eyes that have undergone lensectomy versus healthy eyes. Accommodative effort increases SC size in healthy eyes, but not in eyes that have undergone lensectomy. CONCLUSIONS: Lensectomy is associated with a reduction in SC size and a loss of physiologic SC dilatation during accommodative effort, which may reflect a reduction in outflow facility and may contribute to the development of glaucoma after lensectomy.


Subject(s)
Cataract Extraction/adverse effects , Glaucoma/etiology , Limbus Corneae/physiopathology , Trabecular Meshwork/physiopathology , Accommodation, Ocular/physiology , Adolescent , Anterior Eye Segment/diagnostic imaging , Biomechanical Phenomena , Child , Child, Preschool , Cross-Sectional Studies , Female , Glaucoma/physiopathology , Humans , Lens Implantation, Intraocular , Male , Pseudophakia/physiopathology , Tomography, Optical Coherence/methods
11.
Eur J Ophthalmol ; 29(5): 499-503, 2019 Sep.
Article in English | MEDLINE | ID: mdl-30270661

ABSTRACT

PURPOSE: Trauma is an important cause of visual loss in children and may affect their quality of life. Prevention and legislation can reduce the incidence of trauma, and appropriate and timely treatment can improve prognosis. We aimed to describe incidence of eye injuries in children and the adherence to national and local management guidelines. METHODS: Retrospective service evaluation at a tertiary hospital (Moorfields Eye Hospital, London, UK) which operates a dedicated children's eye casualty. The electronic patient administration system and electronic patient record system (Openeyes) were used to identify children who presented with eye injuries between January 2015 and December 2015. RESULTS: Of 2397 first-time attendances to our children's casualty, 508 were for injuries (estimated incidence 21.1%, 95% confidence interval: 19.5%-22.7%). Mean age at presentation was 7.51 (standard deviation: 7.97) years; boys were more commonly affected than girls (69%). The most common injury was corneal abrasion, followed by blunt and chemical injury; severe injuries such as penetrating trauma were rare. Injuries were sustained mostly during play or sports. Two children sustained permanent loss of vision in the affected eye. CONCLUSION: Our findings are comparable to other published reports. Adherence to management guidelines is high, but documentation of advice given to families can be improved. Regular training of staff and collaboration with organisations outside the hospital can increase awareness of eye injuries in children.


Subject(s)
Eye Injuries/epidemiology , Adolescent , Child , Child, Preschool , Emergency Service, Hospital , Eye Injuries/physiopathology , Eye Injuries/therapy , Female , Humans , Incidence , Infant , Male , Prognosis , Quality of Life , Retrospective Studies , Treatment Outcome , Vision Disorders/physiopathology , Visual Acuity/physiology
12.
Eye (Lond) ; 32(11): 1752-1759, 2018 11.
Article in English | MEDLINE | ID: mdl-30013158

ABSTRACT

AIMS: To evaluate retreatment rates, visual and anatomical outcomes at 1-year postnatal age in infants treated for retinopathy of prematurity (ROP) METHODS: Longitudinal national surveillance study of infants treated for ROP in the United Kingdom between December 2013 and December 2014, supported by the British Ophthalmic Surveillance Unit. Here we report retreatment rates, anatomical, visual and refractive outcomes at 1-year follow-up. RESULTS: One-year follow-up forms were completed for 168 children of the original cohort of 327 (51.4%). Twenty-two had at least one retreatment: 17/153 right eyes (REs, 11.1%) after initial diode laser, and 5/14 REs (35.7%) after initial injection of anti-vascular endothelial growth factor (VEGF) antibody. Median (interquartile range) RE best-corrected visual acuity was 0.6 (0.4-1.0) (n = 46 REs), and median acuity both eyes open 0.4 (0.3-0.7) logMAR (n = 89). Median spherical equivalent (RE) was 0.44 (-1.3 to 1.3) dioptre (D) (n = 116). Median astigmatism (RE) was 0.5 (0-1.0) D (n = 111), and median anisometropia 0.125 (0-0.75) D (n = 116). Twenty-four children (20.5%) had been prescribed glasses. Sight impairment certification eligibility information was available for 131 children: 11 (8.4%) were eligible to be certified as sight impaired, and 5 (3.8%) as severely sight impaired. CONCLUSIONS: Retreatment rates are in line with previous reports, and appear higher after initial anti-VEGF antibody than after initial diode laser. Refractive outcomes are in line with previous studies, with a trend towards early emmetropia and myopia following diode laser, particularly in more severe ROP.


Subject(s)
Retinopathy of Prematurity/therapy , Retreatment/statistics & numerical data , Angiogenesis Inhibitors/therapeutic use , Astigmatism/physiopathology , Female , Follow-Up Studies , Humans , Infant , Infant, Newborn , Laser Coagulation , Male , Refraction, Ocular/physiology , Retina/pathology , Retinopathy of Prematurity/pathology , Retinopathy of Prematurity/physiopathology , United Kingdom , Visual Acuity/physiology
13.
BMJ Open ; 7(3): e013366, 2017 03 21.
Article in English | MEDLINE | ID: mdl-28325857

ABSTRACT

OBJECTIVES: To estimate the incidence of severe retinopathy of prematurity (ROP) requiring treatment and describe current treatment patterns in the UK. DESIGN: Nationwide population-based case ascertainment study via the British Ophthalmic Surveillance Unit and a national collaborative ROP special interest group. Practitioners completed a standardised case report form (CRF). SETTING: All paediatric ophthalmologists providing screening and/or treatment for retinopathy in the UK were invited to take part. PARTICIPANTS: Any baby with ROP treated or referred for treatment between 1 December 2013 and 30 November 2014, treated with laser, cryotherapy, vascular endothelial growth factor (VEGF) inhibitor or vitrectomy/scleral buckling, or a combination. MAIN OUTCOME MEASURE: Incidence of ROP requiring treatment. RESULTS: We received 370 CRFs; 327 were included. Denominator from epidemiological data: 8112 infants with birth weight of <1500 g. The incidence of ROP requiring treatment was 4% (327/8112, 95% CI 3.6% to 4.5%). Median gestational age was 25 weeks (IQR 24.3-26.1), and median birth weight 706 g (IQR 620-821). Median age at first treatment was 80 days (IQR 71-96). 204 right eyes (62.39%) had type 1 ROP, and 27 (8.26%) had aggressive posterior ROP. Infants were also treated for milder disease: 9 (2.75%) right eyes were treated for type 2 ROP, and 74 (22.63%) for disease milder than type 1 with plus or preplus, which we defined here as 'type 2 plus' disease. First-line treatment was diode laser photoablation of the avascular retina in 90.5% and injection of VEGF inhibitor in 8%. CONCLUSIONS: ROP treatment incidence in the UK is 2.5 times higher than previously estimated. 8% of treated infants receive intravitreal VEGF inhibitor, currently unlicensed. Research is needed urgently to establish safety and efficacy of this approach. Earlier treatment and increasing numbers of surviving premature infants require an increase in appropriate eye care facilities and staff. TRIAL REGISTRATION NUMBER: NCT02484989.


Subject(s)
Infant, Premature , Patient Selection , Practice Patterns, Physicians' , Retina/pathology , Retinopathy of Prematurity/therapy , Severity of Illness Index , Ablation Techniques , Birth Weight , Female , Gestational Age , Humans , Incidence , Infant , Infant, Newborn , Intravitreal Injections , Lasers , Male , Ophthalmology , United Kingdom , Vascular Endothelial Growth Factor A/antagonists & inhibitors
14.
J Pediatr Ophthalmol Strabismus ; 54(2): 90-96, 2017 Mar 01.
Article in English | MEDLINE | ID: mdl-28092398

ABSTRACT

PURPOSE: To increase the detection rate of strabismus on digital photographs, with the ultimate aim of developing a new automated strabismus detection algorithm. METHODS: In this prospective case series, the authors acquired digital face photographs of 409 children with manifest or latent strabismus, using a 14-million-pixel camera with CCD image sensor. Of the last 52 enrolled, 34 image sets were selected for this study: 29 with manifest and 5 with latent strabismus. Images were taken at a distance of 40 to 70 cm in primary position, with the camera lens as the fixation target and in slight off-center fixation, and using a novel target of small light-emitting diodes mounted onto the camera case. The location of the corneal light reflection was manually calculated in relation to the center of the pupil in both eyes and ocular deviation as the difference in corneal light reflection location between the two eyes. In orthotropia, the expected deviation is zero. RESULTS: In children with phorias, the mean corneal light reflection location difference between the eyes was -0.10 ± 0.14 mm in primary position and -2.02 ± 0.39 mm in off-center fixation. Using a threshold of ±0.5 mm on either side of zero for central and of 2 mm for off-center fixation, sensitivity to detect strabismus increased from 65.6% in central to 79.3% in off-center fixation, respectively. The calculation of specificity will require inclusion of a population of individuals without strabismus. CONCLUSIONS: Off-center fixation onto a near target ensures that participants are actively looking at the target and may increase accommodative effort, thereby increasing the detection rate of strabismus. [J Pediatr Ophthalmol Strabismus. 2017;54(2):90-96.].


Subject(s)
Photography/instrumentation , Pupil , Strabismus/diagnosis , Child , Female , Fixation, Ocular , Humans , Male , Prospective Studies , Reproducibility of Results
15.
Curr Opin Neurol ; 30(1): 74-83, 2017 02.
Article in English | MEDLINE | ID: mdl-28002122

ABSTRACT

PURPOSE OF REVIEW: New insights into triggers and brakes of plasticity in the visual system are being translated into new treatment approaches which may improve outcomes not only in children, but also in adults. RECENT FINDINGS: Visual experience-driven plasticity is greatest in early childhood, triggered by maturation of inhibitory interneurons which facilitate strengthening of synchronous synaptic connections, and inactivation of others. Normal binocular development leads to progressive refinement of monocular visual acuity, stereoacuity and fusion of images from both eyes. At the end of the 'critical period', structural and functional brakes such as dampening of acetylcholine receptor signalling and formation of perineuronal nets limit further synaptic remodelling. Imbalanced visual input from the two eyes can lead to imbalanced neural processing and permanent visual deficits, the commonest of which is amblyopia. SUMMARY: The efficacy of new behavioural, physical and pharmacological interventions aiming to balance visual input and visual processing have been described in humans, and some are currently under evaluation in randomised controlled trials. Outcomes may change amblyopia treatment for children and adults, but the safety of new approaches will need careful monitoring, as permanent adverse events may occur when plasticity is re-induced after the end of the critical period.Video abstracthttp://links.lww.com/CONR/A42.


Subject(s)
Amblyopia/physiopathology , Neuronal Plasticity/physiology , Vision, Binocular/physiology , Visual Perception/physiology , Animals , Disease Models, Animal , Humans , Visual Acuity/physiology
16.
Arch Ophthalmol ; 129(5): 619-27, 2011 May.
Article in English | MEDLINE | ID: mdl-21555616

ABSTRACT

OBJECTIVES: To develop and validate a novel ex vivo model of conjunctival contraction. METHODS: Ex vivo segments of conjunctiva were maintained in culture for 4 weeks in permeable support plates. Digital images were obtained twice a week to monitor contraction using tissue area changes and weekly weight measurements. Investigated were the effects of known contraction stimulators (fetal bovine serum and transforming growth factor ß(2)) and of the matrix metalloproteinase inhibitor GM6001. Microscopic contraction, tissue organization, and cell viability (using the cell vital dye carboxyfluorescein diacetate) were monitored by confocal reflection and 2-photon microscopy, revealing detailed real-time kinetics of tissue remodeling. RESULTS: Fetal bovine serum and transforming growth factor ß(2) induced significant tissue contraction in conjunctiva segments, with no changes in cell viability. This correlated with dramatic and specific degradation of the collagen component in the tissue. Contraction and collagen degradation were reduced in the presence of GM6001. CONCLUSIONS: Ex vivo segments of conjunctiva can be used as an integral model system to provide a higher level of understanding about the efficacy of antiscarring therapies and can help bridge the current gap between in vitro and in vivo models. CLINICAL RELEVANCE: Scarring leads to the failure of several ocular surgical procedures. This novel ex vivo model recapitulates tissue contraction (with kinetics close to that of in vivo scarring) and allows for a more physiological analysis of conjunctival scarring, which could better evaluate potential therapeutic targets.


Subject(s)
Cicatrix/prevention & control , Conjunctival Diseases/prevention & control , Models, Biological , Animals , Cattle , Cell Survival , Cells, Cultured , Collagen/metabolism , Conjunctival Diseases/enzymology , Contracture/drug therapy , Dipeptides/pharmacology , Fibroblasts/pathology , Humans , Matrix Metalloproteinase Inhibitors , Microscopy, Fluorescence, Multiphoton , Protease Inhibitors/pharmacology , Rabbits , Serum/physiology , Swine , Tenon Capsule/cytology , Tissue Scaffolds , Transforming Growth Factor beta2/pharmacology
17.
Eur J Cell Biol ; 90(1): 26-36, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21040999

ABSTRACT

Although fibroblasts play an essential part during the wound healing response, the mechanisms by which they mediate tissue remodelling and contraction are still unclear. Using live cell and matrix imaging within 3D free-floating fibroblast-populated collagen lattices as a model for tissue contraction, we compared the behaviour of a range of fibroblasts with low and high contraction abilities and analysed the effect of the broad spectrum MMP-inhibitor GM6001 on cell behaviour and matrix contraction. We identified two mechanisms underlying matrix contraction, one via direct cell-mediated contractile activity, the second through matrix degradation. These appear to be linked to cell morphology and regulated by the collagen concentration within the matrix. Cells with a rounded morphology proliferated in the matrix but did not remodel it efficiently, resulting in a poor ability to contract matrices. Cells with an elongated morphology showed higher levels of protrusive activity, leading to efficient matrix remodelling and contraction. GM6001 inhibited week-long matrix contraction to various extents with the different cell lines. However, quantitative analysis of the cell protrusive activity showed that GM6001 consistently decreased cell dynamics in 3D by about 20%, and this was correlated with a significant reduction in early matrix contraction. Overall our results suggest that although fibroblast-mediated matrix contraction depends on both cell dynamics and MMP-mediated matrix degradation, the efficiency of GM6001 treatment in preventing contraction might be linked to a direct effect on cell dynamics.


Subject(s)
Cell Movement/physiology , Cell Shape/physiology , Collagen/metabolism , Dipeptides/pharmacology , Extracellular Matrix/metabolism , Fibroblasts/drug effects , Fibroblasts/physiology , Animals , Cell Line , Fibroblasts/metabolism , Humans , Matrix Metalloproteinase Inhibitors , Matrix Metalloproteinases/metabolism , Mice , Microscopy, Confocal , Staining and Labeling , Wound Healing/physiology
18.
J AAPOS ; 13(2): 123-6, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19393510

ABSTRACT

INTRODUCTION: Conjunctival and episcleral bleeding can interfere with visualization of anatomic structures during strabismus surgery. In the United Kingdom, dilute adrenaline (epinephrine) is routinely used to induce vasoconstriction at the beginning of strabismus surgery. Because it causes mydriasis and mildly inhibits accommodation, it is relatively contraindicated if early postoperative suture adjustment is planned. PURPOSE: To test whether topical alpha(2)-adrenergic agonists (brimonidine 0.2% and apraclonidine 1%) are useful alternatives to topical adrenaline (epinephrine) in adjustable suture strabismus surgery. METHODS: Prospective observational pilot study. Brimonidine 0.2% or apraclonidine 1% was applied to the medial or lateral conjunctiva of 10 consecutive adult patients undergoing strabismus surgery with adjustable sutures under general anesthesia. Video images were taken before and up to 20 minutes after instillation. The surface area of ocular surface blood vessels on the acquired images was quantified at selected intervals using imaging software. RESULTS: Both agents induced potent transient vasoconstriction of ocular surface vessels. Within 5 minutes of application, brimonidine reduces blood vessel surface area by 69.2% (95% CI, 50.4-88); this effect persists for 20 minutes. Apraclonidine reduces vessel area by 64.6% (95% CI, 57.2%-72%) within 10 minutes and begins to wear off over the following 10 minutes. CONCLUSIONS: Both brimonidine and apraclonidine may be useful alternatives to topical adrenaline (epinephrine) in adjustable suture strabismus surgery.


Subject(s)
Adrenergic alpha-Agonists/administration & dosage , Clonidine/analogs & derivatives , Quinoxalines/administration & dosage , Strabismus/drug therapy , Strabismus/surgery , Vasoconstrictor Agents/administration & dosage , Adult , Blood Loss, Surgical/prevention & control , Brimonidine Tartrate , Clonidine/administration & dosage , Combined Modality Therapy , Conjunctiva/blood supply , Conjunctiva/drug effects , Humans , Middle Aged , Pilot Projects , Prospective Studies , Vasoconstriction/drug effects
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