Article Date: 12/1/2003

contact lens case reports
Keeping the Eyes Straight With Contact Lenses
BY PATRICK J. CAROLINE, FAAO, & MARK P. ANDRÉ, FAAO

Accommodative esotropia is among the most common forms of acquired strabismus. An intermittent and variable angle of deviation in children who have no generalized neurologic abnormalities characterizes the condition.  It most commonly appears between the ages of 24 and 30 months, although onset before the age of one has occurred.

Despite the early age of onset, some degree of fusion capacity is usually present. Amblyopia develops only if the deviation becomes constant, especially in the presence of untreated anisometropic hyperopia. Traditional thinking viewed accommodative esotropia as a self-limiting condition that often subsided by age 10. However, recent reports have indicated that a high rate of persistence exists beyond that age.

Figure 1. Patient JN with uncorrected accommodative esotropia.

Keeping Things Straight

Your basic treatment objective is to maintain straight eyes by discouraging excessive accommodative convergence. Additionally, appropriate treatment can remove or compensate for coexisting misalignments (oblique muscle dysfunctions) that can act as obstacles to fusion despite adequate control of the esotropia. You can best accomplish these clinical objectives by using optical or pharmacologic intervention.

Generally, the condition is best treated with spectacles that provide the full hyperopic correction. But for ongoing management, you want to provide the least assistance that will keep the eyes straight in binocular viewing. This strategy will help to encourage and expand fusional divergence. Also, in select cases, you can prescribe bifocal lenses for residual esotropia at near.

Figure 2. Strabismus post-full hyperopic contact lens correction.

Putting Strategy into Practice

Patient JN, who is almost three years old, had been diagnosed with accommodative esotropia three months previously. At the time of the initial exam she presented with uncorrected VAs of 20/70 OU with 35 prism diopters of esotropia at distance and 50 at near. We initially prescribed the full cycloplegic refraction of +7.00D sphere OU.

Over the next month, the child wore the glasses only intermittently because of a variety of anatomical and emotional factors. JN's mother was a long-term soft lens wearer, so we suggested contact lenses as an option for JN.

We ultimately fit the patient with custom soft contact lenses from Innovations in Sight with parameters of 8.3mm base curve, +7.75D power and 14.2mm diameter OU (Figure 1). JN's mother quickly mastered the necessary application and removal skills, and JN successfully adapted to full-time contact lens wear.

At her last examination the patient was ortho at distance with 10 prism diopters esotropia at near (Figure 2). We will continue to monitor her residual deviation at near and assess her need for a possible bifocal correction at her next visit.

Patrick Caroline is an associate professor of optometry at Pacific University and is an assistant professor of ophthalmology at the Oregon Health Sciences University. Mark André is director of contact lens services at the Oregon Health Sciences University and serves as an adjunct assistant professor of optometry at Pacific University.

 


Contact Lens Spectrum, Issue: December 2003