Clinical Study
Eye advance online publication 26 June 2009; doi: 10.1038/eye.2009.162
The effects of hypoxia on the ERG in paediatric cerebral malaria
J Lochhead1, A Movaffaghy2, B Falsini3, S Harding4, C Riva2 and M Molyneux5
- 1Eye Department, St Mary's Hospital, Newport, Isle of Wight, UK
- 2Institute de Recherche en Ophlatmologie, Lausanne, Switzerland
- 3Istituto di Oftalmologia, Universita Cattolica del S. Cuore, Rome, Italy
- 4St Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK
- 5Malaria Project, Queen Elizabeth Hospital, Blantyre, Malawi
Correspondence: J Lochhead, Consultant Ophthalmologist, Eye Department, St Mary's Hospital, Parkhurst Road, Newport, Isle of Wight, PO305 TG, UK. Tel: +44 02380 795028; Fax: +44 01983 534415. E-mail: jonathan.lochhead@iow.nhs.uk
Received 19 March 2009; Revised 31 May 2009; Accepted 31 May 2009; Published online 26 June 2009.
Abstract
Background/aims
Cerebral malaria (CM) is a disease of high mortality worldwide. It can be associated with malarial retinopathy (MR) resulting from impaired perfusion within the retinal microvasculature. Areas of capillary non-perfusion (CNP) appear white (retinal whitening) on ophthalmoloscopy. In this study, electrophysiological investigations were performed to investigate the physiological consequences of these hypoxic and ischaemic changes.
Methods
Children admitted with CM were assessed for inclusion in the study. Those with MR underwent further detailed fundus assessment to quantify retinal whitening and were then designated a severity score. Electrophysiological recordings were performed using a miniganzfeldt stimulator with calibration to the International Society for Clinical Electrophysiology of Visual (ISCEV) standards. ERG data were then analysed with respect to presence of MR and also graded disease severity.
Results
Thirty-one children were recruited with a diagnosis of CM, 20 had MR (group 1), and 11 had absent MR (group 2). Statistical analyses of these two groups showed a significant relationship between reduced single flash cone b wave amplitude (CBWA) and increased severity of retinal whitening/CNP (P<0.05). Cone and maximal response b : a wave ratios remained >1 in all subjects.
Conclusion
Retinal whitening/CNP in MR is associated with significant changes in ERG cone b wave function. The relatively high b : a ratio is compatible with the high frequency of MR resolution without sequelae.
Keywords:
cerebral, malaria, retinopathy, electrophysiology, ERG
