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Comparison of clinical features between two different types of exotropia before 12 months of age based on stereopsis
Yong-Min Choi1, Seung-Hyun Kim
1Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.
Insights
Early-onset exotropia before 12 months of age shows similar motor outcomes and reoperation rates, regardless of stereopsis. However, primary infantile exotropia (PIE) patients exhibited more dissociative vertical deviation (DVD), inferior oblique overaction (IOOA), and distant suppression.
Area of Science:
- Ophthalmology
- Pediatric Ophthalmology
- Strabismus Research
Background:
- Early-onset exotropia, diagnosed before 12 months of age, presents diagnostic and therapeutic challenges.
- Understanding the long-term clinical characteristics based on stereopsis is crucial for effective management.
Purpose of the Study:
- To compare clinical outcomes and characteristics of two early-onset exotropia types based on stereopsis.
- Differentiate between presumable early-onset intermittent exotropia (EIE) and primary infantile exotropia (PIE).
Main Methods:
- Retrospective case series of 24 patients with early-onset exotropia (onset < 12 months).
- Patients categorized into EIE (excellent stereopsis ≥60 arc seconds) and PIE (stereopsis ≤100 arc seconds) groups.
- Comparison of preoperative and postoperative clinical features including deviation angles, suppression, and associated deviations.
Main Results:
- No significant differences in preoperative or postoperative exodeviation, or reoperation rates between EIE and PIE groups.
- Dissociative vertical deviation (DVD) and inferior oblique overaction (IOOA) were significantly more prevalent in the PIE group.
- Distant suppression was also exclusively observed in the PIE group.
Conclusions:
- While motor outcomes and reoperation rates are comparable, PIE is associated with specific sensory and motor anomalies like DVD, IOOA, and distant suppression.
- Only 25% of patients with early-onset exotropia achieve excellent stereopsis, highlighting the sensory challenges.
Purpose:
To compare the clinical outcomes and characteristics of 2 different types of early-onset exotropia on the basis of stereopsis outcome.
Design:
Retrospective case series.
Participants:
A total of 24 patients with newly diagnosed exotropia before 12 months of age and at least 1 year of follow-up after surgery.
Methods:
The clinical records of all patients were reviewed. Patients were divided into 2 groups according to stereopsis. The presumable early-onset intermittent exotropia (EIE) group was composed of 6 patients (25%) who showed excellent stereopsis of ≥60 arc seconds. The primary infantile exotropia (PIE) group was composed of 18 patients (75%) who showed stereopsis of ≤100 arc seconds. We compared the preoperative and postoperative clinical features of the 2 groups.
Main Outcome Measures:
The age at onset and visit, age at surgery, constancy before surgery, preoperative and postoperative angles of deviation, distant suppression, reoperation rate, and presence of dissociative vertical deviation (DVD) and inferior oblique overaction (IOOA).
Results:
The age at the stereopsis test was 6.8 years in the EIE group and 6.4 years in the PIE group (P=0.41). There was no statistical difference in the mean preoperative exodeviation (32.8 prism diopters [PD] in the EIE group vs. 34.7 PD in the PIE group, P=0.58) and postoperative deviation at the stereopsis test (1.0 PD in the EIE group vs. 2.0 PD in the PIE group, P=0.97). The reoperation rate was 33% in the EIE group and 27% in the PIE group (P=1.00). There was no statistical difference in constancy between the EIE and PIE groups (33% vs. 56%, respectively, P=0.64). However, DVD (61%) and IOOA (56%) were noted only in the PIE group (P=0.016, P=0.024, respectively), and distant suppression was noted only in the PIE group (61%, P=0.016).
Conclusions:
The results indicate that excellent sensory outcome was observed in only 25% of patients with exotropia before 12 months of age, but motor outcome and reoperation rate were not different between the 2 types of exotropia. We observed DVD, IOOA, and distant suppression only in the PIE group.
Financial Disclosure(S):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
