Mays A. El-Dairi

Optical coherence tomography in the eyes of normal children.

OBJECTIVE To collect a normative database of macular thickness, retinal nerve fiber layer (RNFL) thicknesses, and optic nerve topography in the healthy eyes of children aged 3 to 17 years using optical coherence tomography (OCT) measurements. METHODS Scans were obtained for 286 healthy children (black, 114; white, 154; other, 18). Each child had a dilated eye examination, an axial length measurement using the IOL Master (Carl Zeiss Meditec, Dublin, California), and OCT measurements using the fast macular map, fast RNFL thickness, and fast optic disc protocols of the Stratus OCT (OCT-3; Carl Zeiss Meditec). RESULTS Black children had smaller macular volume and foveal thickness, larger RNFL thickness, and larger cup-disc area ratios compared with white children. Macular volume and average outer macular thickness correlated negatively with axial length in white children. Foveal thickness correlated positively with age in black children only. Average RNFL correlated negatively with axial length in white children only (P < .05 for all). Normative data for all variables were recorded and compared with reported adult values. CONCLUSIONS Stratus OCT-3 measurements of macular and RNFL thickness and optic nerve topography vary with race, axial length, and age in healthy children. Normative pediatric OCT data should facilitate the use of OCT in assessing childhood glaucoma and other diseases.

Optical coherence tomography in the evaluation of neurofibromatosis type-1 subjects with optic pathway gliomas.

PURPOSE Neurofibromatosis type 1 (NF1) is the most common neurocutaneous disorder, with an approximate incidence of 1 in 3,500. Optic pathway gliomas (OPGs) develop in 15% of individuals with NF1, commonly in childhood. OPGs are difficult to detect via a clinical inspection in children, often requiring magnetic resonance imaging (MRI). Given the significant visual risks associated with OPGs in NF1, there is a need for improved noninvasive techniques to diagnose OPGs in children; therefore, we studied optical coherence tomography (OCT) as a potential tool to assess optic nerve and retinal nerve fiber layer (RNFL) abnormalities. This prospective study was designed to evaluate OCT detection of RNFL loss from optic atrophy attributable to OPGs in a cohort of pediatric patients with NF1. METHODS With the use of Stratus OCT, directed testing with the Fast Macular Thickness and Fast RNFL Thickness protocol scans were performed on 9 subjects with NF1 and known OPGs, 6 subjects with NF1 without OPGs, and 15 controls. RESULTS NF1 subjects with OPGs had thinner RNFLs and macula when compared with age-matched controls and to NF1 subjects without OPGs. After applying the equivalence equation, the average RNFL thickness and macular volume in NF1 subjects without OPGs was equivalent to controls. CONCLUSIONS Our study suggests that OCT can be used to detect RNFL thinning secondary to OPGs in NF1 subjects. This objective tool shows promise as a useful adjunct to routine clinical ophthalmologic evaluation in children with NF1.

Reproducibility of spectral-domain optical coherence tomography measurements in adult and pediatric glaucoma

Purpose:To determine the reproducibility of spectral-domain optical coherence tomography (OCT) measurements of peripapillary retinal nerve fiber layer (RNFL) and macular retinal thickness of the central 20-degree area of the posterior pole in adult and pediatric glaucoma and normal subjects. Study Design:Prospective. Methods:Normal, glaucoma suspect and glaucoma eyes of adult and pediatric subjects were recruited. Spectralis OCT scans were obtained 3 times on the same day (intravisit) and 4 weeks later (intervisit). Six individual sectors, average RNFL, and macular retinal thickness using an 8×8 mm grid centered on the foveal pit were measured for all the eyes. The central 16 square areas centered on the foveal pit were called the central macular area and the surrounding 48 square areas were called the perimacular area. Intraclass correlation coefficient, coefficient of variation (COV), and test-retest variability were calculated. Results:Included were 51 adult eyes and 25 pediatric eyes. The intravisit and intervisit intraclass correlation coefficient for the central macular, perimacula, and average RNFL was very good (>0.8) for all adult and pediatric normal and glaucomatous eyes. The mean COVs of normal and glaucomatous eyes were higher for average RNFL (1.5±1.5% adults, 1.0±0.9% pediatric) compared to the central macula (0.56±0.54% adults, 0.68±0.64% pediatric) and perimacular thickness (0.64±0.51% adults, 0.57±0.42% pediatric) (1-way analysis of variance, P<0.05). No difference was noted in the intravisit and intervisit COVs between the adult and pediatric eyes of central macula, perimacula, and average RNFL thickness (unpaired t test, P>0.05). No intervisit reproducibility analysis was available for pediatric glaucoma eyes. Conclusion:The reproducibility of Spectralis spectral-domain-OCT were very good for both RNFL and macular thickness measurements in glaucoma/glaucoma suspect eyes of adult and pediatric subjects.

Correlation between Optical Coherence Tomography and glaucomatous optic nerve head damage in children

Aim: To compare analysis of macular and nerve fibre layer thickness by optical coherence tomography (OCT) with optic nerve head (ONH) morphology based on stereophotography. Design: Prospective observational case–control series. Methods: Normal and glaucomatous eyes of children (age 4–17 years) were scanned using Stratus OCT (Carl Zeiss Meditec, Dublin, California, USA). Fast macular and retinal nerve fibre layer (RNFL) thickness map were performed on 372 eyes of 222 children. ONH stereophotographs were taken and evaluated by two masked observers using a grading system of 0 to 5 based on both cupping ratio and morphology. OCT3 analyses were compared across ONH grades for different areas around the macula and the peripapillary RNFL. Results: Analysis included OCT values and ONH grading for 139 eyes of 139 children. There was a negative correlation between ONH grade and both macular thickness and RNFL thickness in all areas measured. There was a difference in the correlation identified for black versus white children. Conclusion: OCT measurements of RNFL and macular thickness declined with increasing grade of glaucomatous damage seen on stereophotographs in black and white children. Further study will help quantify the value of OCT in the diagnosis and management of paediatric glaucoma.

Evaluation of Optic Nerve Development in Preterm and Term Infants Using Handheld Spectral-Domain Optical Coherence Tomography

PURPOSE To evaluate effects of prematurity on early optic nerve (ON) development and the usefulness of ON parameters as indicators of central nervous system (CNS) development and pathology. DESIGN Prospective, cross-sectional, longitudinal study. PARTICIPANTS Forty-four preterm infants undergoing retinopathy of prematurity (ROP) screening and 52 term infants. METHODS We analyzed ON from portable handheld spectral-domain optical coherence tomography (SD-OCT) images (Bioptigen, Inc, Research Triangle Park, NC) of 44 preterm and 52 term infants. The highest-quality ON scan from either eye was selected for quantitative analysis. Longitudinal analysis was performed at 31-36 weeks and 37-42 weeks postmenstrual age (PMA). Preterm ON parameters also were assessed for correlation with indicators of cognitive, language, and motor development and CNS pathology. MAIN OUTCOME MEASURES Vertical cup diameter (vCD), vertical disc diameter (vDD), vertical cup-to-disc ratio (vCDR), cup depth, and indicators of neurocognitive development and CNS pathology. RESULTS At 37-42 weeks PMA, preterm infants had larger vCD and vCDR than term infants (908 vs. 700 μm [P<0.001] and 0.68 vs. 0.53 μm [P<0.001], respectively), whereas cup depth and vDD were not significantly different. Longitudinal changes (n = 26 preterm eyes; mean interval, 4.7 weeks) in vDD and in vCDR were an increase of 74 μm (P = 0.008) and decrease of 0.05 (P = 0.015), respectively. In preterm infants (n = 44), periventricular leukomalacia was associated with larger vCD (1084 vs. 828 μm; P = 0.005) and vCDR (0.85 vs. 0.63; P<0.001), posthemorrhagic hydrocephalus was associated with shallower cup (331 vs. 456 μm; P = 0.030), and clinical magnetic resonance imaging was associated with larger vCDR (0.73 vs. 0.64; P = 0.023). In 23 preterm infants with Bayley Scales of Infant Development scores, larger vCDR was associated with lower cognitive scores (P = 0.049). CONCLUSIONS This is the first analysis of ON parameters in premature infants using SD-OCT. It demonstrated that by age of term birth, vCD and vCDR are larger in preterm infants who were screened for ROP than in term infants. In this prospective pilot study, ON parameters in these preterm infants associate weakly with CNS pathology and future cognitive development. Future prospective studies with larger numbers are necessary before further conclusions can be made.

Correction of Ocular Shape in Retinal Optical Coherence Tomography and Effect on Current Clinical Measures

PURPOSE To address the misrepresentation of the eye in retinal optical coherence tomography (OCT) images and to examine the effect of this misrepresentation on retinal thickness measurements. DESIGN Prospective case series. METHODS Five subjects with recent orbital magnetic resonance imaging (MRI) scans and normal eye examinations were consented from the clinics of the Duke Eye Center. Each subject had both eyes imaged using a retinal spectral-domain OCT system and ocular biometry measured. Two types of individualized optical models of the subject eyes-numerical and analytical-were used to determine the spatial paths of the OCT A-scans. These paths were used to reorient the A-scans in the associated retinal OCT images and generate corrected images. Using curvature as a general measure of shape, the radii of curvature of the retinal pigment epithelium in the original and corrected OCT images were compared to the ocular radii of curvature in the MRI images. Differences between the retinal thickness maps derived from the original and corrected OCT images were then determined. RESULTS The retinal curvatures were substantially flatter in the original OCT than in the MRI images (mean paired difference: 52.8 ± 41.8 mm, P < .001). Correcting the OCT images decreased the paired differences between OCT and MRI (numerical: 1.6 ± 2.3 mm, P = .091; analytical: 1.9 ± 4.3 mm, P = .278). Retinal thickness measurements between the corrected and uncorrected images differed, with a root mean square difference of 5.61 μm over the entire 6-mm extent of the image; this difference was greater peripherally (6.02 μm) than centrally (2.54 μm). CONCLUSIONS Optically based algorithms can be used to correct the shape of the retina as represented in OCT; this correction makes OCT more consistent with other clinical imaging techniques. Resultant retinal thickness maps were minimally affected by the change in shape. Ocular shape correction should be considered in future development of posterior segment OCT-based morphologic measurements.

A Shot of Adrenaline

Acute macular neuroretinopathy is a rare disorder characterized by the sudden onset of unilateral or bilateral paracentral scotomas with relative sparing of the central vision that occurs mostly in young women. It is often characterized by wedge-like macular lesions. The cause of acute macular neuroretinopathy is unknown but viral, immunological, and vascular etiologies have been proposed. There is no current treatment and the visual prognosis is variable. We describe a young woman in whom this disorder was associated with the administration of epinephrine.

Pediatric optic neuritis.

In clinical practice, the term optic neuritis (ON) refers to an idiopathic, demyelinating inflammatory condition of the optic nerve. As is the case with so many other pediatric diseases, when compared with a similar disease process in adults, pediatric ON is a distinct clinical entity from its adult counterpart in terms of epidemiology, clinical manifestations, and future neurological implications. In this review article, we will outline the clinical manifestations of pediatric ON, highlight the differences between pediatric ON and adult ON, discuss our current understanding of the relationship between pediatric ON and multiple sclerosis (MS), and emphasize the need for a prospective pediatric ON treatment trial.

Anatomic and visual function outcomes in paediatric idiopathic intracranial hypertension

Background There is a paucity of literature describing risk factors for vision loss in paediatric idiopathic intracranial hypertension (IIH). We investigate the final visual function, spectral domain optical coherence tomography (SD-OCT) and enhanced depth imaging (EDI)-OCT findings in children with papilledema caused by IIH. Methods Medical records of 31 patients with paediatric IIH (age ≤17 years) were retrospectively reviewed. Optic disc photographs on presentation and automated perimetry, SD-OCT and EDI-OCT imaging on final follow-up visit were statistically analysed to identify patient characteristics and anatomic findings associated with irreversible vision loss. Results Permanent visual acuity or visual field loss developed in 19% of study eyes. Papilledema of modified Frisén grade ≥3 on presentation was highly predictive of permanent vision loss (p<0.001), while associations between pubertal status and visual function outcome failed to reach statistical significance. SD-OCT revealed optic atrophy in 13% and photoreceptor loss in 19% of eyes, with both findings highly associated with vision loss (p<0.0001). Optic disc drusen was noted in 48% of study eyes by EDI-OCT but was not found to be predictive of visual outcome. Conclusions Clinical observation of high papilledema grade on presentation is predictive of poor visual outcomes. Vision loss is associated not only with optic atrophy but also with photoreceptor damage. Interestingly, a high proportion of study eyes had optic disc drusen, which was not associated with vision loss, but can be a diagnostic challenge in distinguishing true papilledema from pseudopapilledema.

Differentiating Glaucomatous from Non-Glaucomatous Optic Nerve Cupping by Optical Coherence Tomography

Background: In clinical practice, the differentiation of glaucomatous from non-glaucomatous cupping can be difficult, even for experienced observers. The purpose of this study was to evaluate the role of optical coherence tomography (OCT) in differentiating glaucomatous from non-glaucomatous optic nerve cupping in a cross-sectional pilot study. Methods: Eleven consecutive patients presenting to the Duke Eye Center from September 2007 to July 2008 with non-glaucomatous optic nerve cupping and 12 patients with glaucomatous optic nerve cupping were identified. All patients underwent Stratus® OCT imaging: fast macular map, fast retinal nerve fiber layer (RNFL) 3.4 thickness, and fast optic disc protocols. Automated visual field perimetry was performed on the date of OCT scan in non-glaucomatous cupping patients, and from 0-9 months of scan date in glaucoma patients. Eyes were matched by optic nerve cup-to-disc area ratio; average and mean deviation were calculated for each variable. Results: For a similar average RNFL, patients with non-glaucomatous optic nerve cupping had lower nasal and temporal RNFL thickness, as well as lower macular thickness and volume compared to patients with glaucomatous optic nerve cupping. Conclusion: OCT appears to be a useful technology in differentiating glaucomatous from non-glaucomatous optic nerve cupping. The pattern of RNFL loss appears more diffuse in non-glaucomatous optic nerve cupping compared to glaucomatous optic nerve cupping. Future studies with larger sample size and specific neuro-ophthalmic causes of optic nerve cupping may further elucidate the role of OCT in this clinical setting.