EPOS
European Paediatric Ophthalmological Society
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41 Objective perimetry in a paediatric population
Grigg, J.1, Mahmood, S.1, Lloyd, C.1,
Spencer, F.1, Parry, N.1, Henson, D.2
Manchester Royal Eye Hospital, University of Manchester
Purpose: To report the ability of the multi-focal pattern visual evoked potential (MFVEP) to measure visual fields in a paediatric population. The technique has been shown to be effective in adult populations (1).
Method: 9 normals and 8 patients with congenital glaucoma were tested. The MFVEP was recorded (8 mins/eye) using cortically scaled multi-focal pattern stimuli with the ObjectiVisionä system up to 27° eccentricity. An array of four bipolar occipital electrodes was used.
Results: Results are divided into 2 groups for anaylysis 1) Comparison of the MFVEP with Humphrey perimetry results and 2) Those unable to perform subjective perimetry comparison was made with other clinical peramaters such as optic disc morphology. Results for the first group show good topographic correlation between the two techniques. In those unable to perform subjective perimetry the results corresponded with optic disc morphology. In 1 case where subjective perimetry suggested a false positive scotoma the MFVEP was able to demonstrate a normal field. Recordings showed good reproducibility within individuals.
Conclusion:s: The multi-focal multi-channel VEP can objectively detect glaucomatous visual field defects. Asymmetry analysis and EEG scaling reduce variability and have the potential to detect early defects. This technique permits the clinical application of objective perimetry to a paediatric group.
1. Klistorner A, Graham S, Grigg J, Billson F. Multi-focal topographic VEP: improving objective detection of local visual field defects. Investigative Ophthalmology.