Binocular Function in Subjects with Orthotropic Duane Retraction Syndrome

ABSTRACT

Introduction and Purpose: The aim of this study is to evaluate binocular vision parameters such as near point of accommodation (NPA), near point of convergence (NPC), fusional vergence ranges in subjects with orthotropic Duane retraction syndrome (DRS) and to compare with normal age-matched controls

Patients and Methods: A total of 24 subjects (14 Type 1, 2 Type 2, 8 Type 3 DRS) who were diagnosed to have DRS and 15 normals were included in the study. The following binocular vision parameters were assessed in all subjects: amount of the deviation (for near and distance in all gazes), NPC, NPA, positive and negative fusional vergence (PFV and NFV) reserve and stereopsis.

Results: Accommodative amplitude was normal in subject with DRS (median (95% confidence interval (CI):15D (11.9–18.1)) compared to age-matched controls. However, NPC was significantly receded (median [95% CI]:17 cm [14.4–19.6]). PFV reserve and NFV reserve were reduced in subjects with DRS. Subjects with Type 3 DRS have poor PFV reserve and NFV reserve for distance when compared to Type 1 DRS (p = 0.009 and 0.006 respectively). Stereopsis was poor in the subjects with DRS (p < 0.001).

Conclusion: Subjects with DRS have good accommodation, but have poor convergence and fusional vergence. Stereopsis was noted to be poor as well.

KEYWORDS:

• Duane retraction syndrome
• accommodation
• convergence
• fusional vergence

Acknowledgments

We acknowledge Mr Naresh Gattu for taking the clinical pictures of the patients.