Visual outcome in 879 children
treated for strabismus: insufficient accommodation and vision deprivation,
deficient emmetropisation and anisometropia.
(Résultats visuels de 879 enfants pris en charge pour un strabisme :
insuffisance accommodative, amblyopie, emmétropisation déficeinte et
anisométropie)
Ingram RM, Lambert TW, Gill
LE.
Kettering General Hospital, Northants, United Kingdom.
robertingram@tiscali.co.uk
PURPOSE: To
identify the effect of infant hypermetropia on residual amblyopia in children
remaining after treatment.
MATERIALS AND METHODS: 879 strabismic children had cycloplegic
retinoscopy at the age of 6 months and later when strabismus was diagnosed. A
total of 26 hypermetropes consistently wore glasses from the age of 6 months,
and 305 other hypermetropes had their accommodation periodically assessed by
dynamic retinoscopy before strabismus was diagnosed. The relation between the
last known visual acuity after treatment and all other clinical findings was
analysed using t-tests and regression analysis.
RESULTS: Vision less than 6/12 in nonfixing eyes was associated with
infantile hypermetropia > +5.0D, and in rare instances in excess of -3.0D of
myopia. In hypermetropes only, anisometropia was associated with worse amblyopia.
Astigmatism was associated with myopia and low levels of hypermetropia but not
with worse vision. The vision of fixing eyes that were hypermetropic was
significantly worse than that of emmetropic or myopic eyes. Wearing spectacles
from the age of 6 months was associated with better vision in the nonfixing eye.
Vision in the nonfixing eye of 19 hypermetropic heterotropes who started wearing
glasses between 6 and 18 months of age also was better than that of those who
started wearing glasses after 18 months of age. Insufficiency of accommodation
was related to the degree of infantile hypermetropia, to worse vision and to
failure to emmetropise. Difference in amplitude of accommodation between the
eyes was largest in hypermetropes with anisometropia > +1.50 D and was
marginally associated with worse vision in microtropes who became anisometropic
after infancy. Hypermetropia decreased more in fixing eyes than in nonfixing
eyes, thereby causing anisohypermetropia to increase after infancy. This change
was most pronounced in hypermetropic microtropes. Conversely, failure of fixing
eyes to emmetropise was associated with an increase in their inability to
accommodate and heterotropia.
CONCLUSIONS: On the basis of these findings, severe residual amblyopia in children remaining after treatment could be explained by additional vision deprivation. It can be reduced by starting spectacle correction of hypermetropia before the age of 18 months. Anisometropia seemed the result of deficient emmetropisation.
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