Characteristics and course of patients with deteriorated monofixation syndrome

Opinions on Amblyopia Treatment in Microtropia - A Questionnaire Study of Orthoptists in Scandinavia

Background

Microtropia is a small angle strabismus of less than or equal to ten prism diopters. It often co-exists with anisometropia, and patients may require amblyopia treatment. Diplopia following amblyopia treatment is considered rare, but older literature can advise caution when treating amblyopia in microtropia. This study aimed to explore orthoptists' opinions on amblyopia treatment in microtropia.

Methods

Orthoptists working in Scandinavia were invited to complete an online questionnaire regarding their views on amblyopia treatment. They were presented with three different clinical scenarios: 1) patient with anisometropia; 2) patient with anisometropia and microtropia with identity; and 3) patient with anisometropia and microtropia without identity.

Results

The questionnaire received responses from 30 orthoptists, which were analysed. The results showed a significantly higher concern for diplopia in patients with microtropia undergoing amblyopia treatment than in patients with anisometropia. They responded that to prevent diplopia, it is more important to stop amblyopia treatment before equal visual acuity (VA) is reached in microtropia compared to anisometropia. Thus, amblyopia treatment was stopped more often in microtropia, even if VA was improving and diplopia was absent. Equal VA was perceived to be more difficult to achieve in microtropia, both with and without identity, compared to anisometropia.

Conclusion

Despite more recent evidence that diplopia following amblyopia treatment is extremely rare, orthoptists working in Scandinavia reported more concerns about diplopia when treating amblyopia in microtropia than in anisometropia. Stopping amblyopia treatment in microtropia before equal VA was achieved was considered somewhat important to prevent diplopia. Orthoptists also reported that equal VA was difficult to achieve in patients with microtropia, both with and without identity. Further research would help improve the evidence and inform clinical decisions about microtropia and amblyopia treatment in microtropia.

Management of patients with small-angle esotropia and subnormal stereopsis using Fresnel prism

PURPOSE

Monofixation syndrome (MFS) is a specific subnormal binocular vision status, either with or without a small deviation. Patients with MFS have a tendency to maintain stable ocular alignment. Correction of refractive errors and occlusion are considered as treatment option for amblyopia, and the status of MFS could be changed with long-term follow-up. The purpose of this study is to evaluate whether a Fresnel prism affected the visual acuity, angle of deviation, and sensory status in small-angle esotropia with subnormal stereopsis presenting with MFS features.

METHODS

Patients with small-angle esotropia within 8 prism diopters (PD) on the simultaneous prism and cover test from 2010 to 2019 were reviewed. Patients with subnormal stereopsis defined as more than 100 s of arc (arcsec) and with the central suppression with peripheral fusion were only included. A Fresnel prism was applied to the dominant eye, and the minimum follow-up period after Fresnel prism treatment was 24 months. We assessed patient clinical characteristics, course and response to therapy including visual acuity, angle of deviation, and stereopsis.

RESULTS

Twenty patients with a mean age of 5.5 ± 1.4 years were included. The mean duration of Fresnel prism treatment was 15.3 ± 10.3 months. After 50.7 ± 17.2 months of follow-up, VA of the non-dominant eye was changed from 0.26 ± 0.20 logMAR to 0.07 ± 0.17 logMAR (P < .001). The initial stereoacuities were 3.54 ± 0.27 log arcsec, ranged from 6000 to 400 arcsec. After the treatment with Fresnel prism, the final stereoacuities were 3.09 ± 0.58 log arcsec, ranged from 6000 to 100 arcsec (P = .001); nine patients (45%) improved stereoacuity more than two octaves. No changes in the angle of deviation or a change of fixation were observed.

CONCLUSIONS

After use of Fresnel prism, there was some improvement in visual acuity and stereopsis in patients with MFS features. Following occlusion and refractive correction, management using Fresnel prism could be attempted in small-angle esotropic patients with amblyopia or subnormal stereopsis.

Persistent binocular diplopia in childhood following successful treatment for esotropia: a case series

INTRODUCTION

Diplopia is rare in children with nonpathological esotropia because facultative suppression develops prior to visual maturation. Our aim is to present five cases of children with binocular diplopia following treatment of childhood esotropia, exploring possible mechanisms for the development of diplopia based upon the patient's history and findings, and discussing treatment for diplopia in this setting.

METHODS

A retrospective chart review of five sequential patients presenting with binocular diplopia following treatment of esotropia was performed. Treatment of esotropia included correction of hyperopic error, correction of anisometropic amblyopia to 20/30 or better, and strabismus surgery as indicated.

RESULTS

Diplopia developed in two children with accommodative esotropia, one child with infantile esotropia and partially accommodative esotropia, and two children with a history of infantile esotropia and consecutive exotropia following surgical correction. Diplopia onset occurred between ages 7 and 11. Four of the five children experienced resolution of diplopia with prism glasses.

CONCLUSION

Children with esotropia before visual maturation may develop persistent diplopia. Clinical features of the children with diplopia in our case series include poor fusion, poor stereopsis, consecutive exotropia, refractive changes, onset of diplopia after 7 years of age, and occlusion therapy for amblyopia. Prisms may be beneficial in controlling the diplopia.

The stability of the monofixation syndrome

PURPOSE

To determine etiology, characteristics, and stability of the monofixation syndrome (MFS) in a chart review of 63 consecutive patients in a private practice of pediatric ophthalmology.

DESIGN

Retrospective, consecutive chart review.

METHODS

The charts of 63 consecutive patients with MFS, encountered from 2007-2012 followed for a minimum of 3 years were included. Best visual acuity, motor angle deviation at near, fusion, and stereoacuity as recorded on the most recent visit during the follow-up period were examined. Stability of the MFS was determined by comparing the dates of diagnosis with the last examination for those patients who remained stable. Decompensated patients were also studied for characteristics and results of secondary surgery.

RESULTS

The etiology of the MFS was esotropia in 58 (92.1%), anisometropia in 2 (3.2%), and exotropia in 3 patients (4.8%). The majority of patients, 57 of 63 (92%), had stable MFS for a mean of 13.9 years. Six esotropic patients decompensated after a mean of 6 years; 5 of these patients were restored to MFS by secondary surgery and 1 spontaneously recovered. Five patients were found to have improved stereoacuity to 60 arc seconds or better by the end of the study.

CONCLUSIONS

The MFS is a relatively stable binocular status during the first 2 decades of follow-up. A small percentage of patients decompensated, requiring secondary surgery to restore the MFS binocular status. A similar small percentage of MFS patients developed a higher grade of stereoacuity when followed for a sufficient interval of time.