Comparison of electroretinogram between healthy preterm and term infants

Abstract

To investigate the retinal development in healthy preterm infants through standard ganzfeld electroretinograms (ERG) and compare the difference of ERG between the healthy preterm and term infants. Forty-nine 49 healthy infants were recruited to this study, including 20 preterm and 29 term infants. All the infants were grouped as follows: term 40 W group (ERG recorded at birth), term 44 W group (ERG recorded at 4 weeks after birth), preterm 35 W group (ERG recorded at birth) and preterm 40 W group (ERG recorded at due date). Standard ganzfeld flash ERG was performed according to the ISCEV standard for the clinical electroretinogram (2008). The ERG amplitudes in the term 44 W group were notably larger than those of the term 40 W group, but there was no significant difference between the two groups for combined-b and cone-b responses. The implicit time of cone-b, combined-a and 30 Hz in term 44 W group was significantly shorter than that in term 40 W group, and there was no significant difference in other ERG responses between the two groups. Amplitude of ERG waves in preterm 35 W group was only 48.7-78.0% of that in term 40 W group, and the difference of all ERG waves between the two groups was statistically significant, but there was no significant difference between the two groups for implicit time of all responses except rod-b. There was no significant difference between the amplitude of ERG waves in term 40 W and preterm 40 W groups; however, implicit time of cone-a and cone-b in term 40 W is significantly longer than that in preterm 40 W group. The ERG amplitudes in the preterm 35 W group were notably smaller than those of the preterm 40 W group, and except cone-a response, the difference between the two groups was statistically significant, while the difference of the implicit time between the two groups was not significant. OPs could not be recorded in some infants. OPs were seen significantly less frequently in the preterm 35 W group than in either the term 40 W group (Fisher exact test, P = 0.006) or the term 44 W group (Fisher exact test, P = 0.02). No other significant inter-group frequency differences were found. The mean amplitude ratio b/a was not significantly different between the four groups (P > 0.05) (analysis of variance). The retina is not fully developed at birth in healthy preterm infants. The preterm ISCEV ERG matures rapidly after birth and by term reaches the degree of maturation found in term born neonates.

Photoreceptor Function in School-Aged Children is Affected by Preterm Birth

“…Healthy fullterm infants have a more immature fullfield electroretinogram (ffERG) response from rods than from cones when measured at birth indicating that cones mature earlier than rods. [3][4][5] A rapid development of the ERG response of both rods and cones takes place during the first 4 months of life, and continues slowly until early school age. 6 The ERG response in prematurely born children is very immature when recorded at 30 weeks of gestational age (GA) with low amplitudes and long implicit times for both rod and cone responses.…”

“…7,8 The ERG matures continuously and in healthy preterm children tested at 40 weeks of gestation the amplitudes reach the level of fullterms tested just after birth. 4 ERG in former preterm schoolchildren has only been performed to a limited extent and mainly in children with previous retinopathy of prematurity (ROP). 9 Prematurely born children have various visual dysfunctions when tested at school age, such as decreased visual acuity (VA), affected visual fields, reduced contrast vision, and increased prevalence of refractive errors and strabismus.…”

Claimed Effects, Outcome Variables and Methods of Measurement for Health Claims on Foods Related to Vision Proposed Under Regulation (EC) 1924/2006

“…It has also been shown that ERG reflects retinal development. In fact, changes in the ERG response during an infant’s growth reflect different developmental stages in photoreceptors, middle retinal layers and more proximal retina [ 47 ].…”

Einfluss der Makulareifung auf Ganzfeld- und multifokales ERG bei ehemaligen Extremfrühgeborenen mit und ohne akute Frühgeborenenretinopathie

“…Bei ansonsten gesunden Frühchen gleichen sich die Antworten zur 40. Woche denen der gesund geborenen Kinder an [12]. Es gibt jedoch Anzeichen, dass sich die ffERG-Antworten bei Frühchen im weiteren Verlauf nicht im gleichen Ausmaß entwickeln wie bei gesunden termingeborenen Kindern und in unterschiedlichen Studien in einem bestimmten Ausmaß entweder in der Photorezeptorfunktion oder auf der Postrezeptorebene reduziert sind [13,14].…”