Optical Coherence Tomography in Normal and Glaucomatous Pediatric Eyes: Nerve Fiber Layer and Macular Analysis versus Optic Disc Morphology

Journal of AAPOS Volume 10 Number 1 February 2006 Preservation of Extraocular Muscles (EOMs) and Motor Nerves in Horizontal Gaze Palsy and Progressive Scoliosis (HGPPS) Joseph L. Demer, Elizabeth C. Engle; Jules Stein Eye Institute, UCLA, Los Angeles, CA Introduction: In HGPPS, hindbrain axon tracts fail to decussate due to mutation of the pathfinding gene ROBO3. HGPPS is manifested by horizontal ophthalmoplegia and progressive scoliosis. Methods: We performed complete ophthalmic examinations of six members of a consanguineous family with HGPPS, three of whom were affected. Three members underwent surface coil magnetic resonance imaging of EOMs and their motor nerves in the orbit, and the brainstem in two family members. Six unrelated control subjects were imaged. Results: All affected subjects had progressive scoliosis. Mean corrected visual acuity in affected eyes was 0.22 ⫾ 0.18 logMAR (20/32), significantly lower than for unaffected eyes at ⫺0.07 ⫾ 0.05 logMAR (20/16, P ⬍ 0.004). All subjects had normal vertical versions, but affected subjects’ horizontal versions were absent even to the vestibulo-ocular reflex. Convergence was spared. Globe retraction was absent. All affected but no unaffected subjects exhibited nystagmus, including pendular horizontal, seesaw, and downbeat. Affected EOMs had normal size and peripheral innervation, but one affected subject had unilateral extorsion of rectus pulleys and bilateral optic nerve hypoplasia. The affected medulla and pons were hypoplastic and fissured, suggesting absence of white matter decussation. The hindbrain was normal in an unaffected family member. Conclusion: HGPPS is a developmental disorder of central conjugate horizontal gaze that spares the EOMs and their motor nerves, as well as convergence, but may affect the optic nerve. The finding of horizontal nystagmus does not exclude diagnosis of HGPPS. Clinicians should seek evidence of scoliosis in patients presenting with horizontal gaze palsy. Reference: Jen JC, et al. Mutations in a human Robo gene disrupt hindbrain axon pathway crossing and morphogenesis. Science 2004;304:1509-13. High-Resolution Magnetic Resonance Imaging (MRI) Demonstrates Abnormalities of Orbits and Extraocular Muscles (EOMs) in a Novel Moebius-Like Cranial Neuropathy Sean Dumars, Joseph Demer; Jules Stein Eye Institute, David Geffen Medical School at University of California, Los Angeles, CA Introduction: Moebius syndrome typically presents as congenital facial palsy with abduction impairment. We used MRI to examine a family with features of Moebius syndrome. Methods: We examined three related family members with complete opthalmoplegia, blepharoptosis, and facial diplegia. Orbits were imaged with T1-weighting in quasi-coronal and sagittal planes using surface coils. Intraorbital resolution was 234 to 312 microns within 1.5- to 2.0-mm-thick planes. Cranial nerves (CNs) were imaged at the brainstem using head coils and T2-weighting, yielding resolution of 195 microns in planes 1.0 mm thick. Results: The posterior orbits were small with marked hypoplasia of all EOMs. It was not possible to identify motor nerves in the orbits. In the anterior orbit, the EOMs were less hypoplastic while showing an unusually curved path to insert on the globe. The optic nerve was straightened in sagittal views. Brainstems and contiguous CNs III, VI, VII, and VIII were normal bilaterally. Discussion: Familial cases of Moebius syndrome are rare, and our familial cases had the atypical finding of total ophthalmoplegia. Previous MRI studies demonstrated brainstem hypoplasia and absence of cranial nerves in Moebius syndrome. Our patients demonstrated normal brainstem imaging while showing marked posterior hypoplasia of EOMs and deep orbit, yet intraorbital innervation to EOMs was hypoplastic. These clinical and MRI findings are atypical for Moebius syndrome and other described congenital cranial nerve dysinnervation disorders (CCDDs). Conclusion: The clinical and MRI features for this rare family are atypical for Mobieus Syndrome and may represent a unique disorder or Mobieuslike variant in the spectrum of CCDDs. Reference: Verzijl HT, et al. Radiologic evidence for absence of the facial nerve in Moebius syndrome. Neurology 2005 Mar 8;64(5):849-55.

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Role of Optical Coherence Tomography in the Evaluation of Foveal Hypoplasia in Pediatric Nystagmus Charles V. Duss, Dawn N. Maxwell, Suqin Guo, Patrick DeRespinis, Rudolf Wagner; New Jersey Medical School, Newark, NJ Introduction: The underlying cause of poor visual acuity in pediatric patients with nystagmus is not always clear from a clinical exam; specifically, the diagnosis of foveal abnormalities can be challenging. We evaluate the role of Optical Coherence Tomography (OCT) in assessing foveal anatomy in pediatric patients with nystagmus. Methods: Potential patients were identified by chart review from pediatric ophthalmology clinics. Five suitable patients underwent a complete eye exam with dilated fundus exam as well as OCT imaging. Each OCT image was evaluated for abnormalities compared to normal controls and patients with known foveal hypoplasia. Results: Abnormalities of foveal anatomy were documented in two of the five study patients. Abnormalities included complete absence of the fovea and abnormal foveal anatomy. Discussion: The clinical exam is often difficult or inconclusive in pediatric patients with foveal abnormalities occurring with nystagmus. Foveal hypoplasia has been documented in cases of nystagmus occurring with diseases such as ocular albinism and aniridia; however, it may occur outside of these syndromes. OCT plays an important role in assessing foveal abnormalities and may have the additional benefit of predicting visual prognosis by analysis of anatomic characteristics. Conclusions: Optical Coherence Tomography is a useful tool in the assessment of poor visual acuity in pediatric patients with nystagmus. It is particularly useful in diagnosing foveal hypoplasia or foveal abnormalities that may be difficult or impossible to diagnose using only a clinical exam. Based on our early results, we recommend the use of OCT in establishing or confirming a diagnosis of foveal abnormalities in pediatric patients with nystagmus. Optical Coherence Tomography in Normal and Glaucomatous Pediatric Eyes: Nerve Fiber Layer and Macular Analysis versus Optic Disc Morphology Mays A. El-Dairi MD, Sandra I. Holgado CO, MD, Sanjay G. Asrani MD, Laura B. Enyedi MD, Sandra S. Stinnett DrPh, Sharon F. Freedman MD; Duke University Eye Center, Durham, NC Introduction: Optic nerve head (ONH) stereophotography is integral to the evaluation of adults with glaucoma. Optical coherence tomography (OCT) analysis of the peripapillary nerve fiber layer (NFL) and macular thickness in adults has recently also proven valuable. Comparing OCT analysis of NFL and macula in children, Hess et al. (Am J Ophthalmol 2005;139:509-17) found a significant difference between normal and glaucomatous eyes of children. We further propose a correlation between glaucomatous ONH damage and macular and NFL analysis by OCT. Purpose: To compare analysis of macular and nerve fiber layer thickness by OCT3, to ONH morphology based upon stereophotography. Methods: Normal and glaucomatous eyes of children aged 4 to 17 years were included. OCT 3 (Carl Zeiss Meditec, Dublin, CA) was used to obtain a fast macular and NFL thickness map for each eye. ONH stereophotographs were taken and evaluated by two masked observers, using a grading system of 0 to 6 based on both cupping ratio and morphology. OCT3 analyses were compared across OHN grades for the superior, inferior, and temporal macula, as well as for the NFL at several locations around the ONH (Hess et al. AJO 2005;139:50917). Results: Analysis included OCT values and ONH grading for 159 eyes (99 children). Spearman correlation revealed a moderate relationship between ONH grade and both macular thickness, as well as NFL thickness in all areas measured; for example, for the macular volume the correlation coefficient was 0.47 (P ⬍ 0.0001) with a slope of ⫺7.95 (P ⬍ 0.0001). Conclusion: We report that OCT measured NFL and macular thickness decline with increasing glaucomatous damage to the ONH in children. Further study will help quantify the value of OCT in the diagnosis and management of pediatric glaucoma.