Improvement of visual acuity and visual evoked patterned potentials done at different spatial frequencies after rehabilitation in 45 subjects affected by Cerebral Visual Impairment.

Abstract

Purpose To analyze improvement of visual acuity(VA) and visual evoked patterned potentials (pVEP) in children diagnosed by MR as cerebral visual impaired (CVI) after rehabilitation (refractive correction and occlusion terapy). Methods In 45 CVI infants(mean age 5.6)we analysed VA and pVEPs improvement after 1 year of follow up. Teller Acuity Cards and/or optotype were used for decimal visual acuity. P‐VEPs were recorded at Oz,O1,O2, referenced to Fz. At least two spatial frequencies (among 300’,120’,60’,30’,15’).Statistical analysis were made between VA and pVEP improvement. Results VEP and VA percentage of success was 100% and 89% respectively at the beginning; after 1 year VA percentage of success rised 100%. Mean VA before treatment was 2,29/10(0.2‐10); after treatment was 3,61/10(0.1‐10). VA improvement was statistically significant(z=0,00) VA improvement occurred in 68,89%, while 31,11% were unimproved. Improved VEP were 80% and unimproved 20%. We considered improved VEP when children were able to detect lower spatial frequencies or when, in the same spatial frequency, we found higher amplitudes and reduced latencies. Differences between VEP amplitude and latency were not statistically significant in all frequencies but in L60’ (T‐test L60':0.02). There was an association between VA improvement and therapy,(Pr = 0.02) There wasn’t association (Pr = 0.76) between VEP improvement and therapy. There wasn’t correlation between VA and VEP improvement. Conclusion We found an improvement both in VA and VEP.VEP improvement is independent of therapy,VA improvement is correlated with therapy.