Prism treatment of acute acquired concomitant esotropia precipitated by visual confusion

Clinical features and treatment of near-work-related acquired esotropia

AIM

To investigate the characteristics of near-work-related esotropia and the clinical efficacy of botulinum toxin type A (BTXA) injection therapy on it.

METHODS

A total of 107 patients aged 15-57y with near-work-related esotropia were taken as the BTXA-treated group, and 30 other peers without near-work-related esotropia were included in the control group. All participants were refractive corrected to analyse the clinical characteristics of near-work-related esotropia. All subjects were examined including Worth4 spot examination, stereoscopic vision, strabismus angle, accommodative convergence to accommodation ratio (AC/A), far and near positive and negative convergence, positive and negative fusion range, positive and negative relative accommodation. Clinical efficacy was evaluated at a period of 10mo follow-up.

RESULTS

The distant and near stereopsis were found in 84.9% and 77.5% of patients in the BTXA-treated group, respectively. In the control group, all patients had distant and near stereopsis. The incidence of taking off one's glasses to see close objects was significantly higher in the BTXA-treated group than in the control group (P<0.05). The BTXA-treated group showed a smaller range of in-fusion (9.84±5.72)° than the control group (22.04±8.71)° (P<0.05). The near esotropia angle of the BTXA-treated group (17.08±11.98)^Δ was significantly smaller than the distant esotropia angle (19.07±11.68)^Δ (P<0.05). Ten months after injection, the diplopia and esotropia of most patients underwent improvements after treatment (P<0.05).

CONCLUSION

This study reveals that the accommodation function and the habit of near work without wearing spectacles are associated with near-work-related esotropia, while the length of time for near work and the onset time are independent of near-work-related esotropia. Additionally, BTXA injection therapy plays a vital role in relieving diplopia and restoring eye position.

Prismatic treatment of acute acquired concomitant esotropia of 25 prism diopters or less

Background

This study aimed to assess the efficacy of prismatic treatment in a step-by-step manner to reduce prismatic strength in acute acquired concomitant esotropia (AACE) of 25 prism diopters (PD) or less.

Methods

In this retrospective comparative study, 36 patients with AACE with deviation angle ≤ 25 PD were treated with Fresnel prism in a step-by-step manner to reduce prismatic strength. The patients were divided into two groups according to whether they regained orthophoria and were weaned off the press-on prisms within 1 year: (1) the treatment-success group, which consisted of patients who had their esotropia eliminated and were weaned off the press-on prisms within 1 year after prism correction, and (2) the treatment-continuing group, which comprised patients who needed to continue wearing a Fresnel prism at 1 year after the beginning of prismatic correction because diplopia and esotropia still existed. Clinical characteristics and cooperation were analyzed and compared between groups.

Results

Fourteen of 36 patients (38.9%) were weaned off the prism and regained orthophoria and binocular single vision within 1 year after prismatic treatment. Compared with the treatment-continuing group, the treatment-success group showed smaller deviation at near and distant fixations (P = 0.024 and P = 0.006, respectively) measured at the beginning of prismatic correction, a shorter time from onset to prismatic treatment (P = 0.02), and a greater percentage of patients exhibiting good cooperation (P < 0.001).

Conclusions

Prismatic treatment in a step-by-step manner to reduce prismatic strength can lead to good outcomes of motor alignment and binocular function in patients with AACE of 25 PD or less. Patients showing good cooperation, smaller angle of esotropia, and shorter duration from onset to treatment tend to eliminate esotropia and be weaned off press-on prisms within 1 year after prismatic correction.

Clinical Classification of Acquired Concomitant Esotropia

BACKGROUND

Classification and management of acquired concomitant esotropia is controversial. We sought to establish a simple clinical classification in order to determine in which cases further investigations in search of underlying pathologies are necessary.

PATIENTS AND METHODS

Observational retrospective study of the files of 175 consecutive patients examined in our unit between 2009 and 2018 for acute convergent strabismus. One hundred and nine patients were selected, after exclusion of infantile, incomitant, or mechanical esotropias, residual esotropias, and patients examined on a single occasion. All patients received a complete orthoptic and ophthalmological examination. We grouped the patients according to their common characteristics.

RESULTS

We established the following categories: 1. Acute esotropia of large angle (20 to 45 prism diopters [PD]), accompanied by mild hyperopia (mean 1.2 D) in children (n = 16) and moderate myopia (mean 3.7 D) in adolescents and adults (n = 13). 2. Decompensated micro-esotropia, which is distinguished from the other categories by the presence of abnormal retinal correspondence (n = 33). 3. Decompensated esophoria, with intermittent deviations of 5 to 30 PD, esotropia being compensated part of the time (n = 25). 4. Esotropia present only at a distance in patients over 50 years of age (n = 20). 5. Small-angle esotropia (< 15 PD) greater at a distance, associated with oculomotor cerebellar syndrome (n = 2). Complementary examinations (MRI or CT scan) were performed on 21 patients, leading to the discovery of a posterior fossa astrocytoma in a 4-year-old boy.

CONCLUSIONS

The recognition of decompensated micro-esotropia and esophoria, as well as distance esotropia of the elderly, avoids unnecessary additional investigations, which are indicated in any type of acute comitant strabismus if associated with any neurological sign or symptom (e.g., headaches, nausea, vertigo, imbalance, poor coordination, nystagmus, or papilledema). In the absence of neurological findings, there is no consensus about the indication of neuroimaging in large-angle acquired concomitant esotropia, but long-term follow-up of patients that do not undergo neuroimaging is strongly recommended in order to identify later occurring intracranial diseases. This is of particular importance with children.

Benefits and side effects of prisms in the management of diplopia in adults: a prospective study

PURPOSE

To analyze the various factors affecting patient satisfaction with prism glasses in adults with diplopia.

METHODS

In this prospective case series, the benefits and side effects of prisms and factors affecting prism satisfaction were assessed by means of a questionnaire.

RESULTS

A total of 134 patients were included. Overall, 58% of patients were highly satisfied, 22% were somewhat satisfied, and 20% were either neutral, somewhat dissatisfied, or very dissatisfied with prism glasses. Prior history of prism use, amplitude of prisms, comitancy of deviation, and type of lenses worn, had no influence on satisfaction rates. The extent of resolution of diplopia was highly correlated with prism satisfaction (P < 0.001), improvement in depth perception (P < 0.001), driving (P < 0.001), and reading (P < 0.008). Up to 22% of the participants noted "bothersome" side effects, including headaches, dizziness, eye strain and pulling (22%), alteration of depth perception (16%), visual distortion (13%), halos (8%), and weight of the prisms (6%).

CONCLUSIONS

In this cohort of adults with diplopia, prisms were beneficial in treating diplopia of different etiologies, incomitance, and a wide range of deviations. The side effects experienced with prism glasses themselves accounted for patient dissatisfaction in our study.