Sensory strabismus--eso or exo?

PURPOSE: The type of horizontal strabismus from loss or impairment of vision is thought to depend on patient age at the time of vision loss. Association between the age at onset of vision loss and development of esotropia vs exotropia will be determined. METHODS: Patients with a diagnosis of sensory strabismus and visual acuity of 20/40 or poorer were reviewed as well as patients with diagnoses consistent with the development of sensory strabismus. Parameters considered were age at onset of vision loss and type of strabismus. Patients were excluded if the age at onset was not clear. RESULTS: Of 123 patients with sensory strabismus reviewed: 82 (67%) had unilateral vision loss; 41 (33%) had bilateral vision loss; 75 (61%) had congenital vision loss; 50 (67%) developed esotropia; 25 (33%) developed exotropia; 48 (39%) had acquired vision loss; 5 (10%) developed esotropia; and 43 (90%) developed exotropia. A significant difference was noted between age at onset and type of horizontal strabismus (X2= 37.44; P <.0001). CONCLUSION: Of patients with congenital vision loss, 67% developed sensory esotropia and 33% developed sensory exotropia. Of those with acquired vision loss, 10% developed sensory esotropia and 90% developed sensory exotropia. Patients with congenital vision loss are significantly more likely to develop esotropia, P <.005, and those with acquired vision loss are significantly more likely to develop exotropia, P <.001.

Visual rehabilitation in a child with diffuse choroidal hemangioma by using aggressive amblyopia therapy with low-dose external beam irradiation.

Diffuse choroidal hemangioma is a congenital vascular hamartoma often associated with hemangiomatous lesions of the brain, orbit, and periocular skin (nevus flammeus) in the Sturge-Weber syndrome. Visual loss from diffuse choroidal hemangioma may result from chronic serous retinal detachments causing retinal pigment epithelial, photoreceptor or cystoid degeneration, and glaucomatous optic atrophy. Low-dose external beam irradiation has successfully resolved exudative retinal detachment and caused shrinkage of the choroidal hemangioma.(1-3) Visual loss in Sturge-Weber syndrome with diffuse choroidal hemangioma often begins during amblyogenic years. Visual rehabilitation may thus require not only therapeutic intervention to address organic disease but also amblyopia therapy. Though many of the previously reported cases address treatment of the diffuse choroidal hemangioma with laser or radiotherapy, none advocate or emphasize treatment of nonorganic amblyopia associated with this condition. We report the case of a child with Sturge-Weber syndrome and unilateral diffuse submacular choroidal hemangioma who developed an exudative retinal detachment that responded to the combination of low-dose external beam irradiation and aggressive amblyopia therapy.

Comparison of methods for determining the AC/A ratio in accommodative esotropia.

PURPOSE: The two most commonly used clinical methods of determining a high AC/A ratio are: 1) the gradient method, and 2) the distance/near disparity method. Significant differences can be found not only between these two methods, but also in the different techniques for the gradient method alone. The purpose of our study is to compare the gradient method using +3.00 lenses for near and -3.00 lenses for distance, and the distance/near disparity method. METHODS: Patients examined over a 2-year period (1995-1997) with a high AC/A ratio esotropia according to the distance/near disparity were grouped according to level of high AC/A ratio, then prospectively measured by the gradient method (using plus lenses for near and minus lenses for distance). All measurements were performed with full spectacle correction in place according to cycloplegic refraction, and with fixation on an accommodative target. RESULTS: Forty-five patients were included. Using both plus and minus lenses, a high AC/A ratio by the gradient method was found in 16 (36%) patients, (2 [12%] with a grade 1; 7 [44%] with a grade 2; and 7 [44%] with a grade 3, by the distance/near disparity method), a normal ratio was found in 6 (13%), and no patient had a low ratio. Twenty-three patients fell into a different category of AC/A ratio using plus lenses for near compared with minus lenses for distance. CONCLUSIONS: The distance/near disparity method appears to diagnose a high AC/A ratio much more frequently than the gradient method. There was some variability in the AC/A ratio with plus versus minus lenses when the gradient method was used. Further study using the gradient method in patients without a significant distance/near disparity is required.

Early-onset accommodative esotropia.

PURPOSE: To determine the frequency of accommodative esotropia with onset by 6 months of age; to determine if the presence or absence of characteristics usually associated with infantile esotropia can help in the diagnosis; and to determine if antiaccommodative therapy is adequate treatment for the esotropia. METHODS: The charts of 100 patients with infantile esotropia, seen over a 2-year period (September 1995 to September 1997), were reviewed. We identified those with at least 2.25 diopters (D) of hyperopia and determined the presence of large angle esotropia (> 30 to 40 prism diopters [delta]), amblyopia, inferior oblique overaction, dissociated vertical deviation, latent nystagmus, and cross-fixation. The success of antiaccommodative therapy, if attempted, was also evaluated. RESULTS: Of 100 patients with infantile esotropia, 15 (15%) were found to have at least +2.25 D. This represented 8% of all patients with accommodative esotropia seen over the same time period. The average age at initial examination was 21 months, although the reported age of onset in all cases was 6 months or less. Two had surgery before presenting to our institute. Eleven of 13 (84%) had 40 delta or less. Six (40%) of the 15 had amblyopia, 5 (33%) had inferior oblique overaction, 3 (20%) had dissociated vertical deviation, 1 (7%) had latent nystagmus, and 4 (27%) had cross-fixation. Of the 13, 7 were given glasses initially, with 3 being fully corrected. Six were not given glasses, all had surgery, and all were given glasses postoperatively for a residual esotropia. CONCLUSION: Fifteen percent of infantile esotropia patients and 8% of accommodative esotropia patients have infantile accommodative esotropia. Other characteristics of infantile esotropia may be present, but are less frequent, and at least 40% are fully corrected with spectacles indicating that when the hyperopia is 2.25 D or greater, antiaccommodative therapy should be instituted before surgery.

Abnormal head posture associated with high hyperopia.

BACKGROUND: An abnormal head posture may be adopted for ocular or nonocular reasons. The most common ocular reasons are to maintain binocularity and to obtain the best possible visual acuity. Patients with undercorrected or overcorrected refractive errors have been reported to adopt a variety of head positions, thought to be an attempt to obtain the best possible visual acuity. METHODS: Five patients with symmetric high hyperopia (at least + 5.00 D) and an abnormal head posture are presented. RESULTS: All five patients demonstrated an abnormal head posture of chin down for fixation without the spectacle correction in place. This abnormal head posture was eliminated by occlusion of either eye and also by wearing of the refractive correction. No patient demonstrated significant strabismus. CONCLUSION: An abnormal head posture when not wearing spectacle correction can occur in children who have high hyperopia and insignificant strabismus. This may be a mechanism by which the best visual acuity is obtained (indicated by the disappearance of the abnormal head posture on wearing of the glasses) and also to maintain binocularity (indicated by the disappearance of the abnormal head posture under monocular testing conditions). The presence of a chin-down abnormal head posture should alert the examiner to the possible presence of high hyperopia and therefore the necessity for a cycloplegic refraction.