Bronwen Walters

Visual field loss in children with craniosynostosis

AimsTo identify visual field deficits in a group of children with syndromic craniosynostosis.MethodsKinetic visual field examination and visual evoked potentials (VEPs) were recorded in 16 children with syndromic craniosynostosis as part of their ophthalmic evaluation. VEPs were analyzed for inter-hemispheric asymmetries and component amplitude and latency, while visual fields were analyzed both qualitatively and quantitatively.ResultsAll children with craniosynostosis were found to have visual field deficits compared to controls. In the Crouzon group, deficits tended to involve the nasal field, while infero-nasal field deficits were the most consistent finding in children with Apert syndrome. Children with Pfeiffers demonstrated the greatest deficits, with severe constrictions affecting the whole visual field. VEPs were asymmetrical in four cases while the P100 component was subnormal in ten of the 16 patients for either amplitude and/or latency.ConclusionAlthough we may speculate about the mechanisms that cause visual field deficits, we currently are unable to explain the reason for the differing types and extent of visual field loss in the different syndromic groups. We can conclude that the visual field deficits do indicate previous or ongoing visual dysfunction that cannot be monitored employing central vision tests alone.

Perimetry in Children: Survey of Current Practices in the United Kingdom and Ireland

Purpose: Visual fields are key functional outcome measures in children with a variety of ophthalmologic disorders. However, reliably assessing fields in children is challenging. We report the findings of a survey of current practices of perimetry in children in the United Kingdom and Ireland. Methods: An electronic questionnaire was sent to Orthoptic Service Heads in July 2008. Respondents were asked for comments regarding visual field testing in children as well as details of the volume and type of perimetry performed in their units, over a 1-year period. Results: Of the 98 (62%) completed questionnaires, 16 departments reported not testing visual fields in children. In total 3675 subjects under 16 years of age were reported to have undergone perimetry in 1 year, most in units with a ≥ 50% pediatric caseload for orthoptics. A total of 42% of units used static perimetry alone, 11% kinetic, and 47% used a combination of both. Conclusion: High numbers of visual field tests are carried out in children in the UK and Ireland annually. Automated perimetry is used predominantly, despite the underlying algorithms having been developed for adult populations. Thus there is a clear need for more research, to ensure that evolving management practices are informed by understanding of the diagnostic accuracy and value of perimetry in children.

Comparison of Quality and Output of Different Optimal Perimetric Testing Approaches in Children With Glaucoma

Importance There is limited evidence to support the development of guidance for visual field testing in children with glaucoma. Objective To compare different static and combined static/kinetic perimetry approaches in children with glaucoma. Design, Setting, and Participants Cross-sectional, observational study recruiting children prospectively between May 2013 and June 2015 at 2 tertiary specialist pediatric ophthalmology centers in London, England (Moorfields Eye Hospital and Great Ormond Street Hospital). The study included 65 children aged 5 to 15 years with glaucoma (108 affected eyes). Main Outcomes and Measures A comparison of test quality and outcomes for static and combined static/kinetic techniques, with respect to ability to quantify glaucomatous loss. Children performed perimetric assessments using Humphrey static (Swedish Interactive Thresholding Algorithm 24-2 FAST) and Octopus combined static tendency-oriented perimetry/kinetic perimetry (isopter V4e, III4e, or I4e) in a single sitting, using standardized clinical protocols, administered by a single examiner. Information was collected about test duration, completion, and quality (using automated reliability indices and our qualitative Examiner-Based Assessment of Reliability score). Perimetry outputs were scored using the Aulhorn and Karmeyer classification. One affected eye in 19 participants was retested with Swedish Interactive Thresholding Algorithm 24-2 FAST and 24-2 standard algorithms. Results Sixty-five children (33 girls [50.8%]), with a median age of 12 years (interquartile range, 9-14 years), were tested. Test quality (Examiner-Based Assessment of Reliability score) improved with increasing age for both Humphrey and Octopus strategies and were equivalent in children older than 10 years (McNemar test, &khgr;2 = 0.33; P = .56), but better-quality tests with Humphrey perimetry were achieved in younger children (McNemar test, &khgr;2 = 4.0; P = .05). Octopus and Humphrey static MD values worse than or equal to −6 dB showed disagreement (Bland-Altman, mean difference, −0.70; limit of agreement, −7.74 to 6.35) but were comparable when greater than this threshold (mean difference, −0.03; limit of agreement, −2.33 to 2.27). Visual field classification scores for static perimetry tests showed substantial agreement (linearly weighted &kgr;, 0.79; 95% CI, 0.65-0.93), although 25 of 80 (31%) were graded with a more severe defect for Octopus static perimetry. Of the 7 severe cases of visual field loss (grade 5), 5 had lower kinetic than static classification scores. Conclusions and Relevance A simple static perimetry approach potentially yields high-quality results in children younger than 10 years. For children older than 10 years, without penalizing quality, the addition of kinetic perimetry enabled measurement of far-peripheral sensitivity, which is particularly useful in children with severe visual field restriction.

THE PHYSIOLOGY OF THE RETINAL PIGMENT EPITHELIUM IN DANON DISEASE.

Purpose: Danon disease is caused by mutations in the lysosome-associated membrane protein-2 gene (LAMP2). In the eye, LAMP2 is expressed only in the retinal pigment epithelium. This study aimed to investigate the previously unreported impact of LAMP2 mutations on the electrooculogram generated by the retinal pigment epithelium. Methods: Four members of a family with Danon disease were examined. All have mutations in c294G > A, of the LAMP2 gene on Xq24, by which no, or aberrant, protein will be formed. Electrooculograms to International Society for the Clinical Electrophysiology of Vision (ISCEV) standards were recorded with full-field electroretinography, Goldmann kinetic visual fields, and spectral optical coherence tomography with fundus autofluorescence imaging. Results: Electrooculogram amplitude ratios of light rise:dark trough, the Arden index, fell at low-normal limits (range: 1.68–3.94) but misrepresent retinal pigment epithelium health, because the absolute dark trough voltages were abnormally low (median: 140 &mgr;V, range: 72–192 &mgr;V) as were the light rise amplitudes (median: 297 &mgr;V, range: 198–366 &mgr;V), and full-field electroretinograms were normal. Hyperfundus autofluorescence and hypofundus autofluorescence changes became more confluent and florid with increasing age of female patients. Goldmann visual field testing showed constriction of the central field. Conclusion: Low electrooculogram voltages indicate that the retinal pigment epithelium is unable to maintain its tight junctions in Danon disease.

Study of Optimal Perimetric Testing in Children (OPTIC): evaluation of kinetic approaches in childhood neuro-ophthalmic disease

Aims We compared feasibility, quality and outcomes of visual field (VF) testing in children with neuro-ophthalmic disease between the discontinued ‘gold-standard’ Goldmann and Octopus perimeters. Methods Children with neuro-ophthalmic disease, attending Great Ormond Street Hospital, London, were assessed using standardised protocols by one examiner in a single sitting, using Goldmann and Octopus kinetic perimetry. Outputs were classified to compare severity of loss and defect type. Test quality was assessed using both qualitative and quantitative methods. Results Thirty children (40% female) aged 5–15 years participated. Goldmann perimetry was completed in full by 90.0% vs 72.4% for Octopus. Inability to plot the blind spot was the most common reason for not completing testing. Over 75% completed a test in ≤20 min. Duration was similar between perimeters (paired t-test, mean difference: 0.48min (−1.2, 2.2), p=0.559). The lowest quality tests were for Octopus perimetry in children <8 years, without significant differences between perimeters in older children (McNemar’s test, χ2=1.0, p=0.317). There was broad agreement between Goldmann and Octopus outputs (good quality, n=21, Bland-Altman, mean difference for isopters I4e (−514.3 deg2 (−817.4, –211.2), p=0.814), I2e (−575.5 deg2 (−900.1, –250.9), p=0.450) and blind spot (20.8 deg2 (5.7, 35.8), p=0.451)). However, VF severity grades and defect type matched in only 57% and 69% of tests, respectively. Octopus perimetry underestimated severe VF defects. Conclusions Informative perimetry is feasible in children ≥8 years with neuro-ophthalmic conditions, with either Goldmann or Octopus perimeters. However, meaningful differences exist between the two approaches with implications for consistency in longitudinal assessments.