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Early Clinical and Subclinical Visual Evoked Potential and Humphrey's Visual Field Defects in Cryptococcal Meningitis.

Moodley, A; Rae, W; Bhigjee, A; Connolly, C; Devparsad, N; Michowicz, A; Harrison, T; Loyse, A (2012) Early Clinical and Subclinical Visual Evoked Potential and Humphrey's Visual Field Defects in Cryptococcal Meningitis. PLOS ONE, 7 (12). e52895. ISSN 1932-6203 https://doi.org/10.1371/journal.pone.0052895
SGUL Authors: Harrison, Thomas Stephen Loyse, Angela

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Abstract

Cryptococcal induced visual loss is a devastating complication in survivors of cryptococcal meningitis (CM). Early detection is paramount in prevention and treatment. Subclinical optic nerve dysfunction in CM has not hitherto been investigated by electrophysiological means. We undertook a prospective study on 90 HIV sero-positive patients with culture confirmed CM. Seventy-four patients underwent visual evoked potential (VEP) testing and 47 patients underwent Humphrey's visual field (HVF) testing. Decreased best corrected visual acuity (BCVA) was detected in 46.5% of patients. VEP was abnormal in 51/74 (68.9%) right eyes and 50/74 (67.6%) left eyes. VEP P100 latency was the main abnormality with mean latency values of 118.9 (±16.5) ms and 119.8 (±15.7) ms for the right and left eyes respectively, mildly prolonged when compared to our laboratory references of 104 (±10) ms (p<0.001). Subclinical VEP abnormality was detected in 56.5% of normal eyes and constituted mostly latency abnormality. VEP amplitude was also significantly reduced in this cohort but minimally so in the visually unimpaired. HVF was abnormal in 36/47 (76.6%) right eyes and 32/45 (71.1%) left eyes. The predominant field defect was peripheral constriction with an enlarged blind spot suggesting the greater impact by raised intracranial pressure over that of optic neuritis. Whether this was due to papilloedema or a compartment syndrome is open to further investigation. Subclinical HVF abnormalities were minimal and therefore a poor screening test for early optic nerve dysfunction. However, early optic nerve dysfunction can be detected by testing of VEP P100 latency, which may precede the onset of visual loss in CM.

Item Type: Article
Additional Information: ©2012 Moodley et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Keywords: Adolescent, Adult, Asymptomatic Diseases, Cohort Studies, Early Diagnosis, Evoked Potentials, Visual, Female, Humans, Male, Meningitis, Cryptococcal, Middle Aged, Vision Disorders, Visual Field Tests, Visual Fields, Young Adult, Science & Technology, Multidisciplinary Sciences, Science & Technology - Other Topics, VAR GATTII MENINGITIS, AIDS PATIENTS, OPTIC-NERVE, SUDDEN BLINDNESS, SOUTH-AFRICA, INFECTION, PRESSURE, PATIENT
SGUL Research Institute / Research Centre: Academic Structure > Infection and Immunity Research Institute (INII)
Journal or Publication Title: PLOS ONE
ISSN: 1932-6203
Dates:
DateEvent
21 December 2012Published
Web of Science ID: WOS:000313158800107
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URI: https://openaccess.sgul.ac.uk/id/eprint/101593
Publisher's version: https://doi.org/10.1371/journal.pone.0052895

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