Accommodative esotropia is an inward deviation related to very high amount of hyperopia or farsightedness. Parents or pediatrician would usually take note of an intermittent deviation when the child is fatigued or ill. If the appropriate optical correction is not given at this insipient stage, the deviation may become constant. Amblyopia could set in once this happens. The sooner the child is treated during the intermittent stage, the better the sensory outcome is. A good sensory outcome implies good binocular vision or high-grade stereopsis.
Accommodative esotropia is a hereditary condition. Most accommodative esotropes have a history of either farsightedness or squint among first or second degree relatives. These kids exhibit significant hyperopia on refraction. Family history and high hyperopia are considered as risk factors for developing accommodative esotropia. Although farsightedness can be corrected with glasses, these should not be given unless they can improve vision and unless there is a history of intermittent or manifest inward deviation. Giving glasses on a prophylactic basis is not recommended.
The aims of prompt treatment of accommodative esotropia include: maintenance of normal binocular visual acuity, restoration of ocular alignment, maintenance of high-grade binocularity, and probably the most difficult, successful weaning from optical correction.
The aims of treatment are more or less achieved provided that optical correction is done at a time that the deviation is still in the intermittent stage. Children with risk factors should be followed up on a regular basis for a cycloplegic refraction to unveil more hyperopia. Parents should inform the family’s pediatric ophthalmologist once any deviation is noticed. A non-accommodative component and amblyopia could set in if treatment is not initiated at the proper time.
The usual initial intervention done is optical correction. This could be in the form of single vision lenses or contact lenses, depending on the age of the child and the motivation of the child and the parents. Bifocals are given to those with high accommodative convergence/accommodation ratio, who exhibit a much larger inward deviation at near. Surgery is usually recommended for those with residual deviation while wearing their full correction. The surgery is done to correct the non-accommodative component. It should be explained to parents that the child will still have to wear the full correction after surgery, in order to correct the accommodative component of the condition.
The average onset of accommodative esotropia is three years of age. However, it may occur much earlier than this. The ideal time to wear glasses for young hyperopes like them is when an intermittent inward eye deviation is noted. Most of the time, the parents or the pediatrician notices this. Wearing the full correction will control the eye deviation.
A regular cycloplegic refraction is recommended because the degree of farsightedness may actually increase by the age of six or seven. It then gradually decreases after this age, so the child may be weaned off the glasses slowly. Children with significantly high hyperopia, however, would most likely be on spectacles or contact lenses until adulthood.
Children with accommodative esotropia are not a homogenous group of patients. The ones who benefit from bifocals are those with high accommodative convergence/accommodation ratio. This subset of patients exerts excessive convergence when focusing on objects at near. The bifocals help straighten their eyes by decreasing the degree of accommodation at near. The power of the bifocal adds are gradually tapered after 7 years of age.
Topical atropine may help in this situation. Atropine will relax accommodation and this could encourage the child to wear the glasses. This is usually employed for the first couple of months of wearing corrective glasses then discontinued.
Unlike normal children, patients with accommodative esotropia exhibit an increase in the amount of hyperopia or farsightedness up to 6 or 7 years of age. After this age, the amount of hyperopia slowly decreases. This is the time that weaning from corrective glasses is usually initiated. This is probably the most challenging part of the treatment because the prescription for correction is gradually decreased by small amounts every 6 months. Tapering of prescription in a gradual fashion is recommended in order to prevent recurrence of the deviation or any deterioration in vision. Children with low degree of hyperopia could be free from glasses during their mid-teens. However, those with moderate to high degrees of hyperopia tend to need to wear their correction until adulthood.
Optical correction is usually the first line of treatment. Most cases are successfully treated with glasses provided that the timing is correct. Giving the glasses during the intermittent stage certainly saves a considerable number of patients from having strabismus surgery for the eye deviation.
Sometimes, a non-accommodative esotropia is superimposed on an accommodative type. This usually happens when there was a delay in optical treatment. Surgery can be done for this deviation. However, this does not mean that your child can be free from glasses after the surgery. She will still need to wear her full correction after the surgery in order to correct the accommodative esotropia due to her high refractive error.
Refractive surgery in young children is still experimental at this stage.