Clinical and Radiologic Findings in Patients With Morning Glory Disc Anomaly and Associated Optic Pathway Enlargement

Clinical Correspondence Clinical and Radiologic Findings in Patients With Morning Glory Disc Anomaly and Associated Optic Pathway Enlargement Abdelrahman M. Elhusseiny, MD, Alexander Kwok, MD, MPH, Alisa Kanfi, MD, Raghu H. Ramakrishnaiah, MD, Paul H. Phillips, MD M orning glory disc anomaly (MGDA) is a rare, sporadic, and, usually, unilateral condition characterized by a funnel-shaped conical excavation of the posterior part of the eye. It has been hypothesized to be due to abnormal development of the lamina cribrosa and posterior sclera during pregnancy.1 Magnetic resonance imaging (MRI) and angiography are indicated to exclude associated intracranial anomalies. Recently, ipsilateral enlargement of the optic nerve or chiasm has been reported with MGDA.2–4 We demonstrate the clinical and radiologic findings in MGDA patients with ipsilateral optic pathway enlargement (OPE). Institutional Review Board approval of the University of Arkansas for Medical Sciences was obtained. We conducted a retrospective chart review from January 2000 through September 2022 of patients diagnosed with MGDA and had OPE on the MRI. Clinical data collected include age, ethnicity, sex, laterality, presenting symptoms, bestcorrected visual acuity (BCVA), cycloplegic refraction, extraocular motility abnormalities, and coexisting ocular pathologies. Radiologic data collected include the surface area of the enlarged optic nerve pathway segment compared with the contralateral normal eye, associated skull anomalies, and intracranial structural or vascular anomalies. Signal intensity and homogenesity on both T1 and T2 MRI scans were also documented. We entered the data using Microsoft Excel 2018 and analyzed it using SPSS Inc, version 24. Clinical features: Six patients (7 eyes) were included. Five patients had unilateral MGDA. The right eye was involved in 4 of 6 patients. Five patients were nonDepartment of Ophthalmology (AME, A. Kwok, PHP), Harvey and Bernice Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas; Department of Radiology (A. Kanfi, RHR), Arkansas Children’s Hospital, University of Arkansas for Medical Sciences, Little Rock, Arkansas; and Department of Radiology (A. Kanfi), University of Cincinnati Medical Center, Cincinnati, Ohio. The authors report no conflicts of interest. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www. jneuro-ophthalmology.com). Address correspondence to Paul H. Phillips, MD, Jones Eye Institute, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72207; E-mail: [e-mail] e396 Hispanic White (83.3%). The median age at presentation was 1.32 years. The median follow-up time range was 5.93 years (see Supplemental Digital Content, Table S1, http://links.lww.com/WNO/A726). Ocular pain was the presenting symptom in one patient. Four patients were referred from an outside provider for strabismus evaluation and one patient for head tilt. On initial presentation, all patients had sensory strabismus (4 patients had esotropia, and 2 patients had exotropia). Two patients underwent strabismus surgery (one had medial rectus recession for esotropia and another had lateral rectus recession for exotropia). The median spherical equivalent at the last follow-up was 20.25 diopters (D) (range: 22.50 to +0.50 D). Other associated ocular findings include heterochromia (1 eye, 14.2%), epicanthal folds (2 eyes, 28.5%), and eyelid hemangioma (1 eye, 14.2%). None of our patients had a retinal detachment or persistent fetal vasculature. Radiologic features: In addition to the funnel-shaped excavation of the optic disc (7 eyes, 100%), associated OPE was seen in the following sections: intraorbital (7 eyes, 100%), intracanalicular (3 eyes, 42.8%), cisternal (6 eyes, 85.7%), chiasmatic (4 eyes, 57.1%), and retrochiasmatic (2 eyes, 28.5%). All cases showed homogeneous signals on T1WI and T2-WI. On T1-WI, the signal was isointense in 7 eyes (100%); however, on T2-WI, the signal was isointense in 4 eyes (57.1%), hypointense in 2 eyes (28.5%), and hyperintense in 1 eye (14.2%). Six eyes (85.7%) had some portion of T1-WI enhancement on postcontrast imaging involving the retrobulbar intraorbital segment (6 eyes, 85.7%) and cisternal segment (2 eyes, 28.5%) of the optic nerve. On diffusion-WI, there was a restriction in 6 eyes (85.7%). Follow-up MRI was performed in all cases, and none showed growth of the lesion on serial MRI (range of follow-up: 4.3–10.5 years). Additional MRI findings of the orbit included uveoscleral discontinuity (7 eyes, 100%) and abnormal tissue suggestive of a glial tuft (7 eyes, 100%). Associated intracranial abnormalities included vascular anomalies (4 cases, 66.6%), cerebellar hemisphere hypoplasia (1 case, 16.6%), and ectopic posterior pituitary (without clinicalhypopituitarism) (1 case, 16.6%) (see Supplemental Digital Content, Tables S2, S3, http://links.lww.com/WNO/A727, http://links.lww. com/WNO/A728) (Fig. 1). Associated intracranial vascular Elhusseiny et al: J Neuro-Ophthalmol 2024; 44: e396-e398 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 1. Axial balanced fast-field echo (BFFE) image (A) showing right-sided morning glory disc anomaly (arrows) with cupping of the optic disc and filling up of the perioptic cerebrospinal fluid space (glial tuft). Coronal T2-weighted image (B) showing ipsilateral enlargement of optic chiasm (arrow) and normal thickness of the optic chiasm on the left (curved arrow). (C) Sagittal fat-saturated T1-weighted image through the sella shows the ectopic posterior pituitary T1 bright spot (arrow). The three-dimensional time of flight MRA image (D) showing smooth narrowing of the right internal carotid artery (moyamoya disease). Notice the normal caliber of the left internal carotid artery (curved arrow). anomalies included one or more of the following: ectasia of the internal carotid artery (ICA), absence of posterior communicating artery, narrowing and irregularity of the ICA, and persistent trigeminal artery. Interpretation of the findings: A retrospective study by Poillon et al3 described similar findings on MRI; however, they did not report the ophthalmic features of their patients. They described 9 eyes with MGDA and OPE. Eight of 9 eyes had optic nerve enlargement, 6 eyes had chiasmal enlargement, and none had retrochiasmal enlargement. In our series, the intraorbital part of the optic nerve was enlarged in all 7 eyes, the optic chiasm was enlarged in 4 eyes, and the retrochiasmal portion was Elhusseiny et al: J Neuro-Ophthalmol 2024; 44: e396-e398 enlarged in 2 eyes, a finding that was not reported before. Poillon et al3 reported that none of their patients demonstrated postcontrast enhancement on T1-WI. Six eyes in our series had postcontrast enhancement involving a small portion of the intraorbital and/or cisternal parts of the optic nerve. None of the patients in our series had a retinal detachment or persistent fetal vasculature, in contrast to Pillion et al3 who reported 2 eyes with retinal detachment and 2 eyes with persistent fetal vasculature. Another series by Thoma et al2 described 3 eyes (3 patients) with MGDA and ipsilateral OPE. Two of their patients had esotropia in the MGDA-affected eye. In our series, all 6 patients had strabismus, 2 of whom e397 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence In conclusion, MGDA is a rare condition that may be associated with OPE with characteristic radiologic findings. The etiology of the OPE is unknown. The enlargement is not consistent with optic pathway glioma because sporadic optic nerve glioma is heterogenous on MRI and may grow over time. In our cohort, the OPE was homogenous in all 7 eyes and stable over a median follow-up of 5.93 years. Longer follow-up of those patients with serial MRI is necessary to evaluate the progression of the condition. STATEMENT OF AUTHORSHIP Conception and design: A. M. Elhusseiny, P. H. Phillips; Acquisition of data: A. M. Elhusseiny, A. Kwok, A. Kanfi, R. H. Ramakrishnaiah; Analysis and interpretation of data: A. M. Elhusseiny, R. H. Ramakrishnaiah, P. H. Phillips. Drafting the manuscript: A. M. Elhusseiny, A. Kwok; Revising the manuscript for intellectual content: P. H. Phillips. Final approval of the completed manuscript: A. M. Elhusseiny, P. H. Phillips. FIG. 2. Axial balanced fast-field echo (BFFE) image (A) showing bilateral morning glory disc anomaly (arrows) with cupping of the optic disc and filling up of the perioptic cerebrospinal fluid space (glial tuft). Postcontrast T1weighted image (B) showing enhancement of the glial tuft. had undergone strabismus surgery. We report the first case of bilateral MGDA (see Supplemental Digital Content, Figure S1, http://links.lww.com/WNO/A725) with bilateral OPE (Fig. 2). Although MGDA is usually unilateral disease, bilateral cases have been reported in the literature.5 e398 REFERENCES 1. Lee BJ, Traboulsi EI. Update on the morning glory disc anomaly. Ophthalmic Genet. 2008;29:47–52. 2. Thoma D, Nijs I, Demaerel P, Casteels I. Morning glory disc anomaly with an ipsilateral enlargement of the optic nerve pathway. Eur J Paediatr Neurol. 2017;21:787–791. 3. Poillon G, Henry A, Bergès O, et al. Optic pathways enlargement on magnetic resonance imaging in patients with morning glory disc anomaly. Ophthalmology. 2021;128:172–174. 4. Nguyen DT, Boddaert N, Bremond-Gignac D, Robert MP. Optic nerve abnormalities in morning glory disc anomaly: an MRI study. J Neuroophthalmol. 2022;42:199–202. 5. Kim MR, Park SE, Oh SY. Clinical feature Analysis of congenital optic nerve abnormalities. Jpn J Ophthalmol. 2006;50:250– 255. Elhusseiny et al: J Neuro-Ophthalmol 2024; 44: e396-e398 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.