Abstract
Purpose :
Infants born prematurely are at higher risk of reduced visual function in later life, however the growth of important retinal structures during the critical early years has not been clearly defined. Using hand-held ultra-high resolution spectral domain OCT (HH SD-OCT) we compared optic nerve head (ONH) development from 37 weeks to 6 years postmenstrual age (PMA) between premature infants previously screened for retinopathy of prematurity (ROP) and full term infants.
Methods :
133 premature infants (≤32 weeks gestational age at birth or ≤1500g birth weight) and 198 full term infants (37-42 weeks gestational age at birth) were recruited to the study. Premature infants were grouped according to previous history of ROP; none, regressed without treatment, or treated. Ophthalmic examination and HH SD-OCT scan (Bioptigen, 2.6µm axial resolution) were performed between 37 weeks and 6 years PMA without sedation in the outpatient clinical setting. ONH images were analysed using a customised macro in ImageJ. Diametric and peri-papillary parameters quantified as distance and visual angle measurements were compared between groups.
Results :
Diametric optic nerve head parameters (disc and cup diameters, cup-to-disc ratio) recorded between 37 weeks and 6 years PMA were statistically similar for infants born prematurely and infants born at full term. In both groups, the mean disc and cup diameter increased with age by 30% and 40%, respectively when described as a fixed distance but remained constant when described as a visual angle. Premature infants treated for ROP did not demonstrate the early reduction in temporal RNFL thickness in the first year as seen in full term and other premature infants. The resulting temporal RNFL was significantly thicker between PMA of 1 and 6 years when compared to all other groups (p<0.001).
Conclusions :
We demonstrate premature infants without a previous history of treated ROP have a similar time course of ONH development after reaching 37 weeks PMA compared to infants born at full term, suggesting abnormalities of visual function in this group are not primarily due to the structure of the optic nerve head. In contrast, premature infants treated for ROP show a significantly thicker temporal RNFL throughout early childhood highlighting the impact of severe ROP on retinal development later in life.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.