Abstract
Purpose:
The effect of strabismus on retinal development has been explored in young children and adults with conflicting results. Recent reports suggest delayed development of the retina in strabismic and anisometropic amblyopes when layers in the retina are reviewed individually. Hand-Held optical coherence tomography (HH-OCT) now provides assessment of the retinal structure in infants and young children. We report the first findings of retinal layers in strabismic infants under the age of 5yrs using the HH-OCT.
Methods:
32 strabismic infants (range 3-54mos), and 41 controls (range 3-53mos), were recruited to the study. Each patient underwent an orthoptic assessment and HH-OCT scans of both eyes. A foveal scan was analysed for both eyes of the strabismic infants and one eye of the control subjects. During analysis scans were randomised and the examiner masked to the condition. ImageJ was used to identify each retinal layer at the fovea and 1000µm nasally and temporally. Age-adjusted comparisons were made between the non-fixing and fixing eye and between the normal and the non-fixing/fixing eye, comparing interactions between age and group.
Results:
Comparisons between the non-fixing and fixing eye revealed no significant difference in any of the layers. Retinal thickness and RNFL were found not to be significantly different between controls and the fixing and non-fixing eye of strabismic infants. A highly significant difference in the rate of RPE development at the fovea and 1000µm nasally and temporally was observed between the controls and the non-fixing eye (interaction between age and group: p=0.0001, p=0.001, p=0.002, respectively) and the fixing eyes of strabismic infants (p=0.008, p=0.006, p=0.066, respectively). A small but significant delay in maturation was found in the nasal and temporal sides of the non-fixing and nasal side of the fixing eye in the strabismic infants when the combined photoreceptor layers (ONL to RPE; increased with age) and combined processing layers (RNFL to OPL; decreased with age) were compared to the controls.
Conclusions:
The main difference between strabismic infants and controls was the rate of RPE development and significant findings in the nasal and temporal side of the processing and photoreceptor layers of the non-fixing eye. Further investigation of retinal development in strabismic and amblyopic infants may be key to understanding the development of strabismus.
Keywords: 724 strabismus: etiology •
550 imaging/image analysis: clinical