Neuro-Ophthalmic Literature Review

Neuro-Ophthalmic Literature Review David A. Bellows, John J. Chen, Hui-Chen Cheng, Michael S. Vaphiades, and Xiaojun Zhang The Medical Eye Center, Manchester, New Hampshire, USA; Departments of Ophthalmology and Neurology, Mayo Clinic, Rochester, Minnesota, USA; Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Ophthalmology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Departments of Ophthalmology, Neurology, and Neurosurgery, UAB Callahan Eye Hospital, Birmingham, AL, USA; Department of Neurology, Ohio State University Medical Center, Ohio, USA; Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, China Characteristics of 110 Patients with Functional Visual Loss Sverdlichenko I, Brossard-Barbosa N, Micieli JA, Margolin E. Characteristics of 110 patients with functional visual loss. Am J Ophthalmol. 2023;250 171–176. Five to 15% of patients who present to a neuroophthalmology practice with a complaint of vision loss are diagnosed with functional visual loss (FVL). To complicate matters, as many as 53% of these patients are also diagnosed with a coexistent organic cause for their loss of vision. To identify the characteristics of patients with FVL, the authors reviewed the records of 110 patients who were diagnosed with FVL at university-affiliated neuroophthalmology clinics. The majority (73.8%) of patients were women with a mean age of 37 ± 15 years. The most common complaints were decreased vision (71.8%) followed by visual field defects (21.8%). In more than half of the patients the complaint was bilateral. Visual acuity improved in 95.9% of patients when tested with fogging and/or a bottom-up technique. The most common visual field defects were generalised depression (42.5%) followed by concentric constriction/tunnel vision (12.5%). Many patients had concurrent mental illness including depression (23.6%) and anxiety (22.7%) as well as other mental health conditions. A history of preceding trauma was present in 35% of patients. These patients incur considerable costs to the health care system. They averaged 4.6 health care visits with 3.7 of these being to medical specialists. They also averaged 2.2 neuroimaging studies in addition to other testing. The authors point out the fact that there can be considerable savings in terms of cost and patient anxiety if these patients are referred promptly for neuro-ophthalmological consultation. David Bellows GLP-1 Receptor Agonists: The Miracle Pill for IIH? Mitchell JL, Lyons HS, Walker JK, Yiangou A, Grech O, Alimajstorovic Z, et al. The effect of GLP-1RA exenatide on idiopathic intracranial hypertension: A randomized clinical trial. Brain. 13 March 2023: awad003. doi: 10.1093/brain/awad003. Epub ahead of print. PMID: 36,907,221. Glucagon-like peptide-1 (GLP-1) receptor agonists are currently used as a treatment for diabetes and weight loss. The Birmingham, United Kingdom group previously showed that GLP-1 receptor agonists reduce cerebrospinal fluid secretion and intracranial pressure (ICP) in a rodent model, which led to their proposal of a randomised, double-blind, clinical trial of exenatide, a GLP-1 receptor agonist, for the treatment of idiopathic intracranial hypertension (IIH). In this trial 15 IIH patients were randomly assigned to either exenatide (n = 7) or placebo (n = 8) and followed with telemetric ICP monitoring for 12 weeks. At 2.5 hours, the exenatide group had a mean ICP reduction of −4.2 mmHg compared with placebo, which was sustained at 24 hours (−4.7 mmHg) and 12 weeks (−4.1 mmHg). Vision also significantly improved in the exenatide arm compared with placebo. There was a trend toward CONTACT John J. Chen Chen.john@mayo.edu Department of Ophthalmology, Mayo Clinic, 200 First Street, Rochester, Minnesota 55905, USA NEURO-OPHTHALMOLOGY 2023, VOL. 47, NO. 4, 232–236 https://doi.org/10.1080/01658107.2023.2216613 © 2023 Taylor & Francis Group, LLC improved headaches in the exenatide group. Surprisingly, despite the improvement in the ICP and visual acuity, there was no significant difference in the perimetric mean deviation or RNFL between the two arms. There was also no significant change in body mss index (BMI) at 12 weeks. Exenatide was fairly well tolerated other than being associated with nausea in many of the patients. This study suggests that GLP-1 receptor agonists have the ability to acutely reduce ICP in IIH, which is independent of their ability to cause weight loss because this effect was noted 2.5 hours after administration and there was no significant difference in BMI at 12 weeks. These data are very promising and support a larger randomised clinical trial for GLP-1 receptor agonists for the treatment of IIH. It will be interesting to see if a larger study demonstrates improvement in perimetric mean deviation and papilloedema. John Chen Onset Before the Age of 9-years-old May be a Better Prognostic Indicator in Childhoodonset Leber’s Hereditary Optic Neuropathy Barboni P, La Morgia C, Cascavilla ML, Hong EH, Battista M, Majander A, et al. Childhood-onset Leber hereditary optic neuropathy – clinical and prognostic insights. Am J Ophthalmol. 2023;249:99–107. The authors conducted a retrospective study to investigate the features of childhood-onset Leber’s hereditary optic neuropathy (LHON). They included two cohorts of LHON patients with onset of visual loss before the age of 12 years old from Italy and the United Kingdom. A total of 68 patients were enrolled in this study. Among them, 14 patients (20.6%) were < 3 years, 27 patients (39.7%) were between 3–9 years, and 27 patients (39.7%) were between 9–12 years. Most of them had subacute bilateral visual loss (66.7%), followed by insidious bilateral (17.3%), unilateral (11.1%) and subclinical bilateral visual loss (4.9%). Generally, patients between 3–9 years old had better visual acuity outcome, mean deviation on visual field testing and higher mean ganglion cell layer thickness on optical coherence tomography. In addition, the proportion of strabismus was higher in patients < 3 years old (21.4%), followed by patients between 3–9 years old (7.4%) and 9– 12 years old (7.4%). The author concluded that children who lose vision from LHON before 9-years-old may have a better visual prognosis than the older ones. LHON should be considered in children with unexplained subnormal vision with associated strabismus. Hui-Chen Cheng Retinal Plasticity May Exist in Early Childhood of Patients with Albinism Lee H, Purohit R, Sheth V, Maconachie G, Tu Z, Thomas MG, et al. Retinal development in infants and young children with albinism: Evidence for plasticity in early childhood. Am J Ophthalmol. 2023;245:202–211. Normal retinal development involves migration of the inner retinal layers (IRLs) away from the fovea, which is almost completed at birth, with elongation of the outer retinal layers (ORLs) over time. The authors conducted a prospective, comparative cohort optical coherence tomography (OCT) study to investigate the time course of foveal development after birth in infants with albinism. The authors enrolled 36 children with albinism, with a total of 181 OCT examinations in comparison to 297 control examinations. In patients with albinism a significant degree of IRL migration was taking place after birth in albinism, which resulted in a significantly thicker central macular thickness compared with controls. In addition, ongoing foveal ORL elongation was noted in albinism patients, although reduced in amplitude compared with controls. The authors concluded that the ongoing retinal development in young children with albinism, albeit at a reduced rate and magnitude compared with control subjects, indicated a period of retinal plasticity in early childhood and raised the possibility of improving visual function in these patients.