Too much or too little: neonatal ocular misalignment frequency can predict later abnormality
- Correspondence to: Anna Horwood, Orthoptic Department, Royal Berkshire Hospital, London Road, Reading, Berkshire, RG1 5AN, UK; a.m.horwood{at}reading.ac.uk
- Accepted 16 February 2003
Abstract
Background: 214 orthoptists’ infants have been followed for up to 15 years, relating neonatal misalignment (NMs) and first convergence onset to later childhood ocular abnormalities. NMs are shown in a companion paper to reflect the onset of first convergence, but if frequent or absent may predict a higher risk of refractive error and esodeviation.
Methods: In a prospective postal survey, orthoptist mothers observed their own infants during the first months of life and regularly reported ocular behaviour and alignment, visual development, and any subsequent ocular abnormalities.
Results: Later strabismus and refractive error were less common in infants who showed NMs occasionally compared with those who never or frequently did. There was a significant linear trend for fewer ocular abnormalities to be found in children with more frequent NMs (p<0.001). Hypermetropes were later to show first convergence than emmetropes or myopes (p = 0.006)
Conclusions: NMs usually reflect an emerging and normally developing vergence system. This study suggests that delayed onset of convergence (and lack of NMs) is associated with later defects, especially hyperopia. Possible causal relations are discussed.
Footnotes
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↵* Angle lambda is the angle between the pupillary axis and the line of sight formed at the centre of the pupil. A positive angle lambda causes the corneal reflection to be nasal to the pupil centre. The terms angle alpha or angle kappa are often used synonymously and are almost identical.
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↵† “Squinting” and “NMs” denote ocular misalignment that may be unilateral or bilateral and may or may not be pathological. At this age it is not possible to differentiate those infants who will progress to show pathological strabismus from those who will subsequently develop normal binocular vision.
