LAUSR

© BMJ Publishing Group Limited 2022. No commercial reuse. See rights and permissions. Published by BMJ. CASE DESCRIPTION A man in his 30s presented with painless progressive diminution of vision in his right eye for 6 months. On examination, visual acuity was 0.32 (20/63) and 1 (20/20), and intraocular pressures were 12 mm Hg and 14 mm Hg in the right and left eyes, respectively. On slitlamp examination, both eyes revealed abnormally thickened structures typically arising within the limbal area and extending superficially towards the central cornea. They were in continuity as well as dichotomously branching (figure 1A,B). His right eye had inferotemporal stromal groundglass haze (figure 1C,D). Corneal sensations were decreased in both eyes. Fundus examination of both eyes revealed normal morphology. Anterior segment optical coherence tomography (Optovue, Fremont, California, USA) showed these structures as hyperreflective foci in corneal stroma with underlying shadowing (figure 2A). Confocal microscopy showed beaded corneal nerves at depths of subepithelium and stroma with wraparound deposits (figure 2B). A diagnosis of bilateral prominent corneal nerves was made, and investigations to know the underlying aetiology were performed (online supplemental table 1). Additional ocular examinations that were done included electroretinogram and Herpes Simplex Virus (HSV) tear film PCR. Systemically, blood pressure was checked and a peripheral neurological examination was done to look for any peripheral nerve thickening or sensation loss. Thereafter, ECG and blood investigations for complete blood count, liver and renal function tests, thyroid and parathyroid hormone profile were performed. ECG suggested arterioventricular block and atrial arrhythmia. These changes have been described in literature to be associated with cardiac amyloidosis for which he was advised consultation in the Department of Cardiology. All other tests were within normal limits, thus ruling out multiple endocrine neoplasia, Refsum’s disease, leprosy, neurofibromatosis, RileyDay syndrome, lipoid proteinosis and ichthyosis. Considering the corneal perineural substance deposition and ECG changes, corneal neural amyloidosis was assumed to be the primary pathology. The patient did not give consent for biopsy in view of satisfactory visual acuity. He was managed conservatively with lubricants, given refractive correction and counselled for the need of corneal transplantation in future. The corneas are specialised tissue innervated by long ciliary nerves, subbranch of the trigeminal nerve with neural plexuses at various levels. They typically have a diameter of 0.2–2 μ. They are unmyelinated Ctype sensory fibres visible only in the periphery where they are thicker and posterior. If the corneal nerve diameter is greater than the normal, it may appear prominent. Thickened or prominent corneal nerves are early hallmarks of important systemic diseases. Observing them and investigating the aetiology may be lifesaving in certain conditions. Lattice corneal dystrophy (LCD) type IV may present with absent or polymorphic amyloidosis. Age and mutation determine the phenotypic appearance. In some cases, there might not be any lattice lines or only a subepithelial groundglass haze on the central or inferior cornea. Some may also present as prominent corneal nerves with amyloid wrapped around them. Zhu et al have described Figure 1 (A,B) Retroillumination image of right and left eyes with thickened corneal nerves arising from limbal cornea and dichotomously branching towards the central cornea. (C) The inferotemporal area of the right cornea with groundglass haze and prominent corneal nerves. (D) Slitlamp biomicroscopic image of the right eye highlighting the corneal nerves from their limbal origin towards the central cornea with dichotomous branching and inferotemporal haze.