Anterior segment optical coherence tomography in early detection of subtle Kayser-Fleischer rings

A 37-year-old female was referred from the neurology clinic to the ophthalmology OPD to screen for a Kayser-Fleischer (KF) ring. She had complaints of bilateral hand tremors since 3 years and head tremors since 6 months. On ocular examination, a faint golden-brown pigmented band encircling the periphery of only the superior cornea was noted, which was suggestive of an early KF ring [Fig. 1a and b]. Cobalt blue filter was used; however, it did not seem to enhance the visibility of KF ring. Gonioscopy was attempted but could not be completed due to the patient’s head tremors. Therefore, AS-OCT was performed to confirm the diagnosis. It showed hyperreflectivity on the endothelium side at the level of Descemet’s membrane (DM), corresponding to the location of the KF band/ring [Fig. 1c and d] only in the superior angle, and similar hyperreflectivity was absent in the opposite inferior angle.Figure 1: (a and b) Clinical picture of the right eye showing a golden-brown pigmented band in the superior peripheral cornea suggestive of a KF ring. (c and d) AS-OCT of the right eye showing the hyperreflectivity of Descemet’s membrane corresponding to the KF ring in the superior peripheral cornea (white arrow in blue circle); similar hyperreflectivity was absent in the opposite inferior angleDiscussion Wilson’s disease is a rare autosomal recessive disorder caused by mutations in the ATP7B gene, resulting in impaired copper transport, which primarily accumulates in the liver, brain, and ocular tissue, leading to neuropsychiatric, hepatic, and ocular manifestations.[1] The diagnostic investigations for Wilson’s disease include 24-hour urine copper measurement, ophthalmological slit-lamp examination for KF rings, blood ceruloplasmin levels, serum copper, and liver biopsy with measurement of quantitative copper.[2] In the eye, copper deposits on DM of the corneal periphery lead to the formation of a KF ring, a golden to greenish-brown band in the peripheral cornea. Approximately 78%–85% of Wilson’s disease with neurologic signs manifest a KF ring compared to around 36%–62% of those with hepatic presentations.[3] However, early detection of subtle KF rings on slit-lamp examination can be challenging,[4] especially in patients with head tremors and for a less experienced ophthalmologist. Moreover, in early presentation, like in our case, deposition is only seen superiorly instead of a complete ring as classically described, which adds to the diagnostic dilemma. Therefore, AS-OCT aids in confirming the diagnosis as it demonstrates hyperreflectivity on the endothelial side/DM layer, corresponding to the location of the KF ring.[5] Our case was an early presentation in the course of the disease, and therefore, the KF band was noted clinically only in the superior cornea instead of the complete ring. AS-OCT showed hyperreflectivity on the endothelium side at the level of DM, corresponding to the location of the KF band/ring [Fig. 1c and d] only in the superior angle, and hyperreflectivity was absent in the opposite inferior angle. Fig. 2 shows a photo essay of a full blown case of Wilson’s disease with a complete KF ring and AS-OCT showing hyperreflectivity on the endothelial side in both angles. Fig. 3 is a photo essay of a refractive error patient without any KF ring, and AS-OCT shows no hyperreflectivity on the endothelial side of either angles.Figure 2: (a) Clinical picture of the right eye showing a golden brown band along the limbus. (b–d) AS-OCT of the right eye showing hyperreflectivity of Descemet’s membrane corresponding to the KF ring (red arrow) in both nasal and temporal angles (c) B – High-resolution spectralis ASOCT highlighting the hyperreflectivity of the descemet's membrane (red arrow) in the nasal angle. (d) AS-OCT of the nasal angle showing hyperreflectivity of the descemet's membrane (red arrow)Figure 3: (a) Clinical picture of the right eye of the normal subject (without a KF ring). (b and c) AS-OCT of the right eye of the normal subject showing no hyperreflectivity of Descemet’s membraneTo conclude, AS-OCT enables the precise measurement and localization of copper deposits, aiding in early diagnosis and monitoring disease progression as well as the treatment response. AS-OCT can be used as an adjunctive imaging test to confirm the presence of KF rings, especially in subtle KF bands (incomplete ring), patients not cooperative for gonioscopy examination, or less experienced ophthalmologists, especially in residency training. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.