Correlation between Cup Disk Escavation Analysed via Hrt Ii and Visual Evoked Potentials in Children Affected by Cvi

Abstract

Abstract: : Aim: to compare anatomical and functional correlations in children affected by CVI by F-VEPs and HRT II. Matherial and methods: we examined with FVEP, under general anaesthesia (O2/air 50%, enriched 3% sevofluorine), five children (age 3-10 years) affected by CVI and showing neuroradiological signs of cerebral damage. HRT II images were taken after eyes dilatation (1% thropicamide administered three times) with a laser digital system λ 679 nm. Tridimensional image is done from 16 to 64 bidimensional images consecutives and equidistants (1/16 mm. each image 384*384 pixel). For the FVEP we used a Lace electronic system with three dish electrodes, the active electrode at inion, the reference at Fz and the ground at the mastoid. FVEP were administered with a strobe flash head presented at a rate of once every 1 sec (xenon linear flash placed about 20 cm above the infant eye, analysis time 300, 500 or 1000ms, 1 joule energy, 54 responses per eye were averaged). We considered all the parameters tested with HRT II as well as the FVEP delays, and the amplitude of the pIV wave. We correlated the results using Pearson's correlation coefficient (r). Results: a good correlation, for the right eye, has been found among the following parameters: delay of pIV and disc area (r:-0.75), rim area (r:-0.52), rim volume (r:-0.46), mean RNFL thickness (r: -0.53); pIV amplitude and disc area (r:0.41), rim area (r:0.50), mean RNFL thickness (r: 0.80); for the left eye there was a good correlation between: delay of pIV and cup volume (r:-0.56), mean cup depth (r:-0.51), max cup depth (r:-0.67); pIV amplitude and rim volume (r:0.57), max cup depth (r:0.61), cup shape measure (r: -0.63). Conclusions: in our sample the morphological parameters (tested using HRT II) well correlated to the functional ones (tested with FVEP): in particular the most affected eye gave the worst results in both examinations.

Keywords: visual development: infancy and childhood • optic disc • visual impairment: neuro-ophthalmological dise