Visual Acuity alterations in Congenital Zika Syndrome (CZS) children from Rio de Janeiro.

Abstract

Purpose : To evaluate visual acuity (VA) in CZS children with and without microcephaly in the city of Rio de Janeiro, RJ, Brazil.

Methods : 45 children with Congenital Zika Syndrome, from Rio de Janeiro, RJ, Brazil, were examined using the Teller Acuity Cards. VA was compared with prior norms and with another cohort from Jundiaí, SP, evaluated by our research team. They had Zika virus-infection confirmed by maternal Real Time Quantitative PCR, serology assay or clinical evaluation. This research was approved by the Ethics Committees for Human Research of the University of São Paulo’s Institute of Psychology (67031216.0.0000.5561) and of the Instituto Fernandes Figueira (IFF) – Fiocruz (526756616000005269) and is in accordance with the Declaration of Helsinki

Results : Most children (41/45 – 91%) had abnormal VA for their age. Out of the total sample of 45 children we had 3 within the normal limits, another 5 within the range of measurement error and 13 between that limit and the legal blindness level (VA 20/200), or a total of 21/45 (47%) with some degree of vision. The remaining children (12/45, 27%) had VA below that value. The only child that did not present microcephaly, had fundoscopic abnormalities. Among the children with microcephaly, 35/44 (78 %) presented visual fundus alterations. A logarithmic regression between VA (LogMAR) and age, calculated to quantify the VA developmental time course showed absence of correlation (R2 = 0.0076; p= 0.087).

Conclusions : There is a strong link between the Congenital Zika Syndrome and VA losses. However, it is difficult to establish if the VA impairment was due to retinal damage, central nervous system damage or a combination of both. It is very relevant to note that about half the sample showed some degree of vision, from normal to the legal blindness limit, while the other half were below that range. This finding reinforces the importance of evaluating VA in CZS children and might have an impact in the management of these children.

This is a 2020 ARVO Annual Meeting abstract.

 

Figure 1 - Visual acuity as a function of age in children with CZS from the Rio de Janeiro cohort. Dots correspond to individual VAs from each of the 45 children examined. The light grey area is delimited by the higher and lower tolerance limits. The darker range corresponds to possible measurement error (0.5 octave). The dotted line corresponds to 20/200 VA.