Publications by authors named "Arvind Chandna"

24 Publications

  • Page 1 of 1

Differential Experience-Dependent Plasticity of Form and Motion Mechanisms in Anisometropic Amblyopia.

Invest Ophthalmol Vis Sci 2019 10;60(13):4109-4119

Department of Psychology, Stanford University, California, United States.

Purpose: We measure neural responses associated with form and motion processing in children with anisometropia before and after treatment with spectacles and occlusion.

Methods: In this prospective, case-control treatment study, 10 children with anisometropia and amblyopia and 16 age-matched visually normal children participated. Steady-state visual evoked potentials (VEP) were recorded from electrodes over the occipital cortex. The visual stimulus comprised a horizontal bar grating into which Vernier offsets were introduced and withdrawn periodically at 3.75 Hz. The VEP amplitude at 3.75 Hz (first harmonic [1F]) and 7.5 Hz (second harmonic [2F]) were recorded to index the sensitivity of form/position-sensitive versus motion/transient-sensitive neural populations, respectively. Response amplitude at 1F and 2F were recorded over a series of 10 logarithmically spaced offset sizes before and after treatment. Main outcome measures are VEP amplitude versus displacement functions, interocular response amplitude differences.

Results: After relaxing into spectacles (minimally-treated state), form/position-sensitive responses in the dominant/less ametropic eye of the children with anisometropia were larger and responses in the more ametropic eye were smaller than those of controls. Motion-transient responses were equal to those of controls in the less ametropic eye, but were smaller than controls in the more ametropic eye. After treatment, responses did not differ from those of controls.

Conclusions: Form and motion responses are differentially susceptible to neural deprivation via optical blur. Form responses are more plastic than motion responses in minimally-treated children with anisometropic amblyopia. Most treatment effects occurred above threshold range, suggesting some treatment effects are not detected clinically.
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http://dx.doi.org/10.1167/iovs.19-27005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6779065PMC
October 2019

Calibration of the PlusOptix PowerRef 3 with change in viewing distance, adult age and refractive error.

Ophthalmic Physiol Opt 2019 07;39(4):253-259

The Smith-Kettlewell Eye Research Institute, San Francisco, USA.

Purpose: The PowerRef 3 is frequently used in studying the near triad of accommodation, vergence and pupil responses in normal and clinical populations. Within a range, the defocus measurement of the PowerRef 3 is linearly related to the eye's defocus. While the default factory-calibrated slope of this relation (calibration factor) is 1, it has been shown that the slope can vary across individuals. Here, we addressed the impact of changes in viewing distance, age and defocus of the eye on the calibration factor.

Methods: We manipulated viewing distance (40 cm, 1 m and 6 m) and recruited participants with a range of accommodative capabilities: participants in their 20s, 40s and over 60 years old. To test whether any effect was larger than the range of measurement reliability of the instrument, we collected data for each condition four times: two in the same session, another on the same day, and one on a different day.

Results: The results demonstrated that viewing distance did not affect the calibration factor over the linear range, regardless of age or uncorrected refractive error. The largest proportion of the variance was explained by between-subject differences.

Conclusions: Calibration data for the PowerRef 3 were not sensitive to changes in viewing distance. Nevertheless, our results re-emphasise the relevance of calibration for studies of individual participants.
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http://dx.doi.org/10.1111/opo.12631DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6852400PMC
July 2019

Multifocal choroiditis with panuveitis in an 8-year-old boy with long-standing idiopathic acute anterior uveitis.

Eur J Ophthalmol 2016 Aug 4;26(5):e114-7. Epub 2016 Aug 4.

Department of Pediatric Ophthalmology, Alder Hey Children's NHS Foundation Trust, Liverpool - UK.

Purpose: To report successful treatment of a rare case of sight-threatening pediatric multifocal choroiditis with panuveitis (MFCPU) and the use of electrophysiology to confirm return of macular function.

Methods: Case report.

Results: An 8-year-old boy with a history of bilateral recurrent non-juvenile idiopathic arthritis acute anterior uveitis (AAU) presented with new-onset blurry vision and floaters in both eyes. Visual acuity had deteriorated to 20/200 right eye and 20/100 left eye. Cells were observed in the anterior chamber and vitreous of both eyes. Ophthalmoscopy showed multiple active small cream-colored chorioretinal lesions and cystoid macular edema (CME) in both eyes in the absence of systemic disease, suggestive of idiopathic MFCPU. Successful rapid visual recovery and resolution of CME confirmed by spectral-domain optical coherence tomography (SD-OCT) was achieved with prompt intensive systemic steroid therapy followed by early introduction of methotrexate. After 9 months, his visual acuities improved to 20/32, and pattern reversal visual evoked potentials and 19 hexagon multifocal electroretinography posttreatment were normal, showing recovery of macular function.

Conclusions: Multifocal choroiditis with panuveitis is rare in children and has not been documented in the presence of previous longstanding recurrent AAU. Onset of floaters in children should alert the clinician to early stages of posterior pole involvement and progression to reduction in vision due to CME requires prompt aggressive steroid therapy monitored by clinical examination, SD-OCT, and electrophysiology, followed by early introduction of immunosuppressive drugs for long-term stability and to avoid steroid-induced adverse effects in children.
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http://dx.doi.org/10.5301/ejo.5000772DOI Listing
August 2016

Comments on infant aphakia treatment study 4.5-year results.

JAMA Ophthalmol 2014 Dec;132(12):1491-2

Department of Ophthalmology, Alder Hey Children's NHS Foundation Trust, Liverpool, England.

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http://dx.doi.org/10.1001/jamaophthalmol.2014.3532DOI Listing
December 2014

Propranolol and periocular capillary hemangiomas: assessment of refractive effect.

J Pediatr Ophthalmol Strabismus 2014 May-Jun;51(3):165-70

Purpose: To assess the effects of systemic propranolol on refractive error in infants with periocular capillary hemangiomas.

Methods: A single-center study of consecutive patients with capillary hemangiomas treated with systemic propranolol. Refractive data were analyzed using Long's matrix formalism and the methods of Harris and Kaye.

Results: Seventeen patients were included. At 6 months postoperatively, hemangioma size reduced from 3,214 to 1,806 mm(3) (standard deviation: 4,122 to 2,441). Mean refractive error in the affected eye significantly reduced: -1.25/0.38 × 36 (95% confidence intervals: -5.08/1.20 × 90 to 1.64/1.43 × 180, P = .048) with a smaller change (P = .06) in the unaffected eye of -1.01/+0.31 × 3.16 (95% confidence intervals: -4.02/+1.12 × 180 to +1.49/+0.51 × 90).

Conclusions: Propranolol produced a clinically significant reduction in the infants' refractive error and anisometropia. The reduction in the total refractive error and anisometropia has not been evident in previous analyses, which have concentrated on the change in the "cylinder" as the principal outcome measure.
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http://dx.doi.org/10.3928/01913913-20140507-03DOI Listing
December 2014

Etanercept in methotrexate-resistant JIA-related uveitis.

Semin Ophthalmol 2014 Jan 31;29(1):1-3. Epub 2013 Oct 31.

Ophthalmology Department, Alder Hey Children's Hospital, Alder Hey Children's NHS Foundation Trust .

Unlabelled: We report our results with systemic Etanercept in patients with juvenile idiopathic arthritis in a joint ophthalmology-rheumatology clinic at a tertiary hospital.

Methods: Patients with JIA on Etanercept were identified from a dedicated uveitis database. A retrospective review of electronic and paper-based patient records was performed.

Results: Nine patients with JIA and current or previous treatment with Etanercept were identified, including six females and three males. Five patients with previous or current uveitis were noted. A further four were under observation for uveitis and required Etanercept for their joint disease. All nine patients had previously been taking Methotrexate, which had a suboptimal response in controlling arthritis or uveitis. Six out of nine patients did not show any uveitis activity at their last follow-up. Eyes of three patients still show signs of active inflammation in the anterior chamber (two on Etanercept and one off Etanercept). Severely impaired visual acuity (PL) was recorded in both eyes of one patient with long-standing persistent uveitis. Moderate visual loss in one eye of one patient was seen. The remaining seven patients did not show any significant loss of vision. Intraocular inflammation was not induced in any patient started on Etanercept.

Conclusion: Etanercept may be useful in controlling JIA-related uveitis or arthritis in a pediatric patient when Methotrexate has had a suboptimal response in controlling the inflammatory activity.
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http://dx.doi.org/10.3109/08820538.2013.839802DOI Listing
January 2014

Presentation of suspected pediatric uveitis.

Semin Ophthalmol 2014 Jan 16;29(1):4-7. Epub 2013 Aug 16.

Ophthalmology Department, Royal Liverpool Children's Hospital , Liverpool , UK .

Unlabelled: Presentation of suspected pediatric uveitis: Pediatric uveitis is usually managed in specialized ophthalmic centers in the UK. Meaningful data acquisition in these clinics may be helpful in clinical governance, and healthcare planning in a specialty that is gradually changing due to changes in treatment choices.

Methods: Retrospective analysis of prospectively acquired data in the Liverpool pediatric uveitis database was performed.

Results: Analysis of our data, based on 147 patients, with a mean age of 10 years, indicated a female to male ratio of 2:1. 99% of patients were Caucasian. Our data indicates 86% of all patients attending the uveitis clinic were diagnosed with juvenile idiopathic arthritis, followed by intermediate uveitis 5% and idiopathic uveitis 4%. 46% of patients required treatment. Systemic treatment included methotrexate (34%), prednisolone (14%), etanercept (6%), ciclosporin (6%), mycophenolate (3%), and infliximab (1%). Severe visual loss (defined by counting fingers or below vision) was seen in 10 eyes despite appropriately treated chronic uveitis.

Conclusion: Our data shows uveitis-related ocular morbidity in a predominantly pediatric Caucasian population. Patients with severe and chronic uveitis may experience significant uveitis-related complications and subsequent visual loss despite aggressive treatment.
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http://dx.doi.org/10.3109/08820538.2013.810288DOI Listing
January 2014

Early diagnosis of Stargardt disease with multifocal electroretinogram in children.

Int Ophthalmol 2014 Jun 13;34(3):613-21. Epub 2013 Jun 13.

Department of Paediatric Ophthalmology, Alder Hey Children's NHS Foundation Trust, Eaton Road, Liverpool, L12 2AP, UK,

To present two pediatric cases where multifocal electroretinogram (mfERG) was able to establish an earlier diagnosis compared to full field electroretinogram (ERG) Case 1: an 11-year-old boy with reduced visual acuity, pale discs, macular pigmentation with white dots bilaterally. Case 2: a 12-year-old girl with reduced vision in her right eye, slight pallor of the right optic disc, intense pigmentation at both maculae and scattered punctate lesions throughout the peripheral fundi. Both had been investigated with electrodiagnostic tests according to the International Society of Clinical Electrophysiology for Vision protocol. Full-field ERGs for both children showed normal responses. Case 1: mfERG revealed a severe reduction in function in the inner 20°. Case 2: mfERG showed attenuated responses in each eye. Clinical examination and mfERG were consistent with Stargardt disease. mfERG is applicable to children and is a sensitive tool for early diagnosis of retinal dystrophies.
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http://dx.doi.org/10.1007/s10792-013-9812-9DOI Listing
June 2014

Corneal endothelial dysfunction in Pearson syndrome.

Ophthalmic Genet 2013 Mar-Jun;34(1-2):55-7. Epub 2011 Sep 21.

Department of Ophthalmology, Southport and Ormskirk Hospital NHS Trust, Southport, UK.

Mitochondrial disorders are associated with well recognized ocular manifestations. Pearson syndrome is an often fatal, multisystem, mitochondrial disorder that causes variable bone marrow, hepatic, renal and pancreatic exocrine dysfunction. Phenotypic progression of ocular disease in a 12-year-old male with Pearson syndrome is described. This case illustrates phenotypic drift from Pearson syndrome to Kearns-Sayre syndrome given the patient's longevity. Persistent corneal endothelial failure was noted in addition to ptosis, chronic external ophthalmoplegia and mid-peripheral pigmentary retinopathy. We propose that corneal edema resulting from corneal endothelial metabolic pump failure occurs within a spectrum of mitochondrial disorders.
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http://dx.doi.org/10.3109/13816810.2011.610862DOI Listing
August 2013

Horner's syndrome and sixth nerve paresis secondary to a petrous internal carotid artery aneurysm.

Semin Ophthalmol 2011 Jan;26(1):23-4

Alder Hey Hospital, Liverpool, UK.

We describe a report of a child with a horner's syndrome and sixth nerve paresis secondary to a petrous internal carotid artery (ICA) aneurysm. Management of this condition involved coiling of the aneurysm and the use of botulinum toxin to manage his strabismus and associated symptoms.
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http://dx.doi.org/10.3109/08820538.2010.541321DOI Listing
January 2011

Abatacept: a potential therapy in refractory cases of juvenile idiopathic arthritis-associated uveitis.

Graefes Arch Clin Exp Ophthalmol 2011 Feb 5;249(2):297-300. Epub 2010 Oct 5.

St Paul's Eye Unit, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP, UK.

Background: Juvenile idiopathic arthritis (JIA) is the most common of all systemic conditions associated with childhood uveitis. Visual impairment has been shown to be as high as 40% of which 10% being blind (6/60 or worse). Due to the lack of well-designed randomized control trials for paediatric uveitis and arthritis there are limited comparative data regarding the efficacy of single or combination treatments. Recently, abatacept was shown to control ocular inflammation in a case of psoriatic arthritis- associated uveitis, seven cases of JIA- associated uveitis and in JIA. We present two cases with JIA-associated uveitis who have responded dramatically to abatacept therapy following unsuccessful therapy with other immunosuppressants. Control of arthritis still represents a challenge with this treatment.

Methods: Prospective review of two patients with refractory JIA- associated uveitis not responding to maximum conventional treatment. Patients were regularly reviewed in the ophthalmology and rheumatology clinics. Assessment of their ocular condition was characterized according to the Standardization of Uveitis Nomenclature (SUN) group.

Results: In case 1, ocular inflammation was brought under control after repeated abatacept infusions. Case 2 showed complete resolution of cystoids macular edema CME and improvement of 5 Snellen's lines in best corrected visual acuity. After 9 months, the ocular condition of both patients remains in remission with steroid sparing. Joint disease was brought to clinical remission in case 2, but not in case 1.

Conclusions: Abatacept is a promising alternative treatment in refractory cases of JIA uveitis but may not be as successful in controlling joint disease. Larger series with long term follow up of biological therapies in paediatric uveitis are essential to assess the efficacy and cost effectiveness.
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http://dx.doi.org/10.1007/s00417-010-1523-6DOI Listing
February 2011

When your eye patient is a child.

Community Eye Health 2010 Mar;23(72):1-3

Consultant Paediatric Ophthalmologist and Chair: Vision for Children, Alder Hey Children's Hospital. Liverpool, UK.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873665PMC
March 2010

Using apraclonidine in diagnosing Horner syndrome in children.

Am J Ophthalmol 2010 May;149(5):869; author reply 870

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http://dx.doi.org/10.1016/j.ajo.2010.01.023DOI Listing
May 2010

Pattern recognition of vertical strabismus using an artificial neural network (StrabNet).

Strabismus 2009 Oct-Dec;17(4):131-8

Department of Paediatric Ophthalmology, Royal Liverpool Children's Hospital, Eaton Road, Liverpool, L12 2AP.

Background: Our goal is to develop an accessible expert system (StrabNet) that will assist in the clinical diagnosis of vertical strabismus, form the basis of a teaching/learning tool, and contribute to the audit process. Potentially, this model can be extended to other strabismus deviations.

Methods: Vertical deviations were separated into eight classifications (diagnoses). An expert system based on architecture of artificial neural networks learned the patterns for each class of deviation based on 10 prism cover-test measurements (9 cardinal positions and near fixation). The expert system was tested with previously unseen and real-patient data. This system was extended to a reduced model requiring only six measurements (primary position, right, left, up, down gaze, and near fixation), and evaluated with real patient data. A freely available Web implementation is available on the Internet at www.StrabNet.com .

Results: The expert system was found to be highly accurate at diagnosing vertical strabismus (100% and approximately 96% for ten and six measurement models, respectively) from one of the eight classes.

Conclusion: StrabNet is of demonstrable value in diagnosing commonly presenting vertical deviations from prism cover test (PCT) measurements. Its potential role in teaching and in audit is identified.
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http://dx.doi.org/10.3109/09273970903234032DOI Listing
March 2010

Spontaneous consecutive exotropia in childhood.

Strabismus 2009 Jan-Mar;17(1):33-6

Department of Paediatric Ophthalmology, Alder Hey Children's NHS Foundation Trust, Liverpoo, UK.

Purpose: Consecutive exotropia is commonly the result of a surgical correction of a primary esotropia but may develop spontaneously. This study examines the clinical characteristics of patients who have developed a spontaneous consecutive exotropia and relates the key features to previously reported findings.

Methods: Patients were identified by routine clinical practice from May 2000 to December 2003 by retrospective case note analysis. Patients that presented with an esotropia that became an exotropia (without surgery or botulinum toxin A) were included.

Results: This study consisted of 14 patients who presented with an esotropia from early weeks of life to almost 4 years. No patients were undergoing occlusion treatment at the onset of the exotropia and no subject had dense amblyopia. The most common characteristics included (1) age of onset of esotropia of 24 months or less; (2) hypermetropic refractive error of +5 DS mean spherical equivalent; (3) lack of binocular single vision.

Conclusion: The results highlight the variability of the condition with no single consistent finding, with the lack of binocular single vision, early onset esotropia, and high hypermetropia being common findings. Amblyopia was not found to be an important characteristic.
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http://dx.doi.org/10.1080/09273970802678818DOI Listing
May 2009

The differential diagnosis of vertical strabismus from prism cover test data using an artificially intelligent expert system.

Med Biol Eng Comput 2007 Jul 5;45(7):689-93. Epub 2007 Jul 5.

Department of Clinical Engineering, Royal Liverpool University Hospital, Liverpool L7 8XP, UK.

An expert system is described for the differential diagnosis of vertical deviation strabismus (squint) from measurements taken in the standard prism cover test. The deviations are represented as optical powers in prism dioptres using the graphic representation of strabismus (after Jampolsky). The expert is implemented in MatLab (Mathworks Ltd., Cambridge, UK) both as a stand-alone program on a PC and as a web application available over the Internet (see http://www.strabnet.com ). In trial and clinical datasets a diagnostic accuracy of 100% was achieved.
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http://dx.doi.org/10.1007/s11517-007-0212-zDOI Listing
July 2007

Vision impairment with an interstitial deletion of the short arm of chromosome 8.

Ophthalmic Genet 2007 Jun;28(2):101-4

Department of Paediatric Ophthalmology, Royal Liverpool Children's Hospital - Alder Hey, Liverpool, United Kingdom.

We describe the phenotype of a male infant with an interstitial deletion of the short arm of chromosome 8 (p. 11.2-p. 21). Visual impairment is a major feature in this case. The clinical, radiographic and electrodiagnostic findings are presented. Only four other cases have been reported in which visual problems are associated with a deletion of 8 p.
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http://dx.doi.org/10.1080/13816810701209610DOI Listing
June 2007

Unsuspected periventricular leukomalacia in children with strabismus: a case series.

Acta Ophthalmol Scand 2007 Sep 22;85(6):677-80. Epub 2007 Mar 22.

Department of Paediatric Ophthalmology, Royal Liverpool Children's Hospital (Alder Hey), Liverpool, UK.

Purpose: We report a case series of seven patients who presented with strabismus and no apparent known neurological deficit.

Methods: A retrospective review of notes was performed on all patients presenting at the Royal Liverpool Children's Hospital (Alder Hey) with strabismus, in whom subsequent investigation revealed the presence of periventricular leukomalacia (PVL).

Results: All seven patients presented with esotropia. One patient also had dissociated vertical deviation. A history of premature birth was elicited in six cases; however, one patient had been born at 42 weeks. Apparently uncomplicated routine surgery produced unexpectedly poor results.

Conclusions: Patients with undiagnosed PVL may present to the ophthalmologist with strabismus and no other apparent neurological abnormality. Where it is suspected that the patient may have suffered a significant hypoxic-ischaemic event, the ophthalmologist should have a low threshold for investigating with magnetic resonance imaging, particularly if the patient shows unexpected outcomes following appropriate treatment. Patients and parents should be counselled on possible suboptimal results prior to the offer of surgical correction of strabismus.
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http://dx.doi.org/10.1111/j.1600-0420.2007.00906.xDOI Listing
September 2007

The repeatability of best corrected acuity in normal and amblyopic children 4 to 12 years of age.

Invest Ophthalmol Vis Sci 2006 Feb;47(2):614-9

Vision Assessment Unit, Department of Ophthalmology, Royal Liverpool Children's Hospital, Liverpool, United Kingdom.

Purpose: The main purpose of this work was to measure repeatability of line-by-line logMAR (logarithm of the minimum angle of resolution) acuity in normal and amblyopic children, while adequately controlling for optical defocus.

Methods: The Lea Symbols Chart is a constant-crowding, equal-logMAR increment chart similar in design to the Early Treatment Diabetes Retinopathy Study [ETDRS] chart. LogMAR visual acuity was tested twice in each eye of 32 amblyopic and 11 normal children. Each test commenced with screening in which one of the three central symbols was chosen for identification starting with the 1.0- or 0.9-logMAR line, progressing to every second line until incorrect identification occurred. Symbol-by-symbol presentation then commenced at the logMAR line containing the last correctly identified symbol. The threshold was recorded as the last logMAR line where four of four or four of five correct responses occurred (i.e., line-by-line scoring). Retesting by the same examiner was identical and occurred within the same session.

Results: There was no significant difference in repeatability among normal, fellow, or amblyopic eyes. The difference between test and retest thresholds lay between +/-0.10 logMAR in 93% of eyes. The 95% limits of agreement for the difference was +/-0.18 logMAR. Repeatability in eyes tested first did not differ from that in those tested second in either the normal or amblyopic groups.

Conclusions: In the age-group tested, the line-by-line method of threshold scoring compares favorably with previous reports of both line-by-line and interpolated threshold scoring. There was no clinically meaningful difference in repeatability between the normal and amblyopic children tested.
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http://dx.doi.org/10.1167/iovs.05-0610DOI Listing
February 2006

Description of a new syndrome: auricular abnormalities and cleft lip in two sibs, in association with cleft palate and unusual opthalmological findings.

Clin Dysmorphol 2006 Jan;15(1):33-5

Merseyside and Cheshire Medical Genetics Service, Department of Clinical Genetics, Alder Hey Children's Hospital, Liverpool, UK.

We describe the association of auricular abnormalities and cleft lip with or without cleft palate in two siblings. One sibling has postauricular pits, profound myopia, nystagmus and retinal pigment abnormalities. The second sibling was a fetus of 23 weeks gestation with severe cleft lip, cleft palate and external ear abnormalities. As this constellation of features has not been described together before, we believe this is a new syndrome.
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http://dx.doi.org/10.1097/01.mcd.0000184968.84280.a8DOI Listing
January 2006

Measurement of position acuity in strabismus and amblyopia: specificity of the vernier VEP paradigm.

Invest Ophthalmol Vis Sci 2005 Dec;46(12):4563-70

Smith-Kettlewell Eye Research Institute, San Francisco, California, USA.

Purpose: An objective measure of positional acuity is desirable in the nonverbal clinical population. This study was conducted to investigate the specificity of the vernier VEP as a measure of positional acuity, evaluating the potential confound of asymmetric motion responses that may be present in some groups of patients. These motion responses could masquerade as position-specific responses, since they occur at the same response frequency as the vernier-related response.

Methods: Twelve observers with early-onset esotropia (EOE), 30 children with untreated amblyopia, and 15 control children underwent swept vernier VEP acuity testing accompanied by a swept motion control stimulus. The control condition was used to detect the presence of artifactual responses not related to position sensitivity. The patients with EOE were selected for high levels of motion asymmetry as documented with oscillating gratings presented monocularly. As a measure of motion confound (penetration), the proportion of first-harmonic responses recorded in the control condition was determined.

Results: The penetration rate in the vernier condition in each study group (EOE: 0.93%; amblyopes: 4.26%; normal subjects: 2.40%) and the entire group (2.85%) was acceptably low. The level of penetration was not significantly influenced by the presence of amblyopia.

Conclusions: The vernier VEP paradigm, when applied in the manner described, can be interpreted as a measure of position sensitivity. The presence of motion asymmetry or untreated amblyopia does not affect the validity of vernier measurements made.
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http://dx.doi.org/10.1167/iovs.05-0792DOI Listing
December 2005

CRYBB1 mutation associated with congenital cataract and microcornea.

Mol Vis 2005 Aug 8;11:587-93. Epub 2005 Aug 8.

Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.

Purpose: The molecular characterization of a UK family with an autosomal dominant congenital cataract associated with microcornea is reported.

Methods: Family history and clinical data were recorded. This phenotype was linked to a 7.6 cM region of chromosome 22q11.2-q12.2, spanning the beta-crystallin gene cluster (ZMax of 3.91 for marker D22S1114 at theta=0). Candidate genes were PCR amplified and screened for mutations on both strands using direct sequencing.

Results: Sequencing of the coding regions and flanking intronic sequences of CRYBB2 and CRYBB1 showed the presence of a novel, heterozygous X253R change in exon 6 of CRYBB1. SSCP analysis confirmed that this sequence change segregated with the disease phenotype in all available family members and was not found in 109 ethnically matched controls.

Conclusions: X253R is predicted to elongate the COOH-terminal extension of the protein and would be expected to disrupt beta-crystallin interactions. This is the first documented involvement of CRYBB1 in ocular development beyond cataractogenesis.
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August 2005

Recovery of contour integration in relation to LogMAR visual acuity during treatment of amblyopia in children.

Invest Ophthalmol Vis Sci 2004 Nov;45(11):4016-22

Vision Assessment Unit, Department of Paediatric Ophthalmology, Alder Hey Childrens Hospital, Eaton Road, Liverpool, United Kingdom.

Purpose: In several studies, researchers have found that integration of orientation information along contours defined by Gabor patches is abnormal in patients with strabismus and in untreated patients with anisometropic amblyopia. In this study, the rate and degree of recovery of contour-integration deficits were compared with the recovery of logMAR (logarithm of the minimum angle of resolution) visual acuity deficits in patients newly diagnosed with amblyopia secondary to anisometropia, strabismus, or both.

Method: Contour-detection thresholds and optotype acuity were measured in 17 newly diagnosed anisometropic amblyopes, in 6 patients with strabismic amblyopia, and in 4 patients with combined anisometropic and strabismic amblyopia. Contour-detection thresholds were measured with a card-based procedure. Treatment comprised full refractive correction and full-time total occlusion therapy, when necessary. Visual function was measured at monthly visits during the course of treatment, with an average follow-up period of 16 weeks (12-24 weeks) for the entire group. Complete data were obtained from 23 patients through 8 weeks of follow-up.

Results: Significant interocular differences in contour-detection thresholds were present in 16 of the 27 patients at the first visit after initial refractive correction. Interocular differences in contour-detection thresholds declined to normal levels in most of the patients within 8 weeks of the initiation of treatment. Interocular acuity differences remained significant in many of the patients (19/23) at 8 weeks of follow-up and continued to decline, but did not fully normalize, over the remainder of the follow-up period.

Conclusions: Refractive correction alone or in combination with occlusion therapy produces a normalization of contour-integration thresholds in amblyopia that is more rapid and complete than that achieved for visual acuity.
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http://dx.doi.org/10.1167/iovs.03-0795DOI Listing
November 2004

Diathermy for posterior capsule opacification.

J Cataract Refract Surg 2003 Mar;29(3):420; author reply 420

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http://dx.doi.org/10.1016/s0886-3350(03)00106-8DOI Listing
March 2003