In vivo retinal development using hand held ultra-high resolution spectral domain optical coherence tomography in premature and full term infants

Abstract

Purpose: To describe in vivo retinal changes during development in premature infants and normal aged matched controls using hand-held spectral domain optical coherence tomography (HH-SDOCT).

Methods: Cross sectional and longitudinal images HH-SDOCT were collected from 33 premature infants ranging in age from 31 - 42 weeks gestational age. Participants were recruited from the neonatal unit while also undergoing ophthalmic screening for retinopathy of prematurity (ROP). Control infants ranged in age from 37 weeks to 41 weeks gestation and were recruited from the maternity unit. Premature infants were examined at 1-2 weekly intervals until up to 42 weeks. Normal controls were examined within 1 week of birth. No premature infants had received treatment for ROP at time of scanning. HH-SDOCT (Bioptigen, 2.6μm axial resolution) scans were performed without sedation and after dilatation of pupils. Customised Image J manual segmentation of retinal images including thickness and angle of each layer centrally and at 1000μm nasally and temporally was performed and quantified. Statistical analysis was completed using SPSS v20.

Results: The central retina in the premature group progressively thinned by 1.74μm/week in contrast to 5μm/week thickening of the nasal and temporal retina located at 1000μm from the foveal centre. Changes in central retina were due to a combination of inner layer migration (reduction of approximately 4.4μm/week) in conjunction with increased thickening of the outer retinal layers. Changes in temporal and nasal retina consisted of thickening of both inner layers and photoreceptor layers. Increase in thickness was primarily seen in nuclear layers (GCL and INL) whereas plexiform layers did not show any significant changes. The premature group demonstrated thicker central retina in comparison to age-matched controls because of disrupted inner layer migration. Outer retinal photoreceptive elements were easier to define in the normal group compared to the premature group.

Conclusions: Premature infants maintain thicker inner retina centrally with decreased inner retinal migration compared to age-matched normal infants. Outer retinal layers were thinner in the premature group suggesting slower development of these layers.

Keywords: 698 retinal development • 550 imaging/image analysis: clinical