Accuracy of accommodation in heterophoric patients: testing an interaction model in a large clinical sample

• Published in: Ophthalmic & physiological optics 2005-11, Vol.25 (6), p.582-591
• Main Authors: Hasebe, Satoshi, Nonaka, Fumitaka, Ohtsuki, Hiroshi
• Format: Article
• Language: English
• Subjects: accommodation; Accommodation, Ocular; accommodation-vergence interaction; accommodative lag; Adolescent; Adult; Biological and medical sciences; Case-Control Studies; Child; Convergence, Ocular; Esotropia - physiopathology; Esotropia - surgery; Exotropia - physiopathology; Exotropia - surgery; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; heterophoria; Humans; Medical sciences; Oculomotor disorders; Ophthalmology; Refractive Errors; Regression Analysis; Vertebrates: nervous system and sense organs
• ISSN: 0275-5408; 1475-1313
• DOI: 10.1111/j.1475-1313.2005.00331.x

A model of the cross‐link interactions between accommodation and convergence predicted that heterophoria can induce large accommodation errors (Schor, Ophthalmic Physiol. Opt. 1999;19:134–150). In 99 consecutive patients with intermittent tropia or decompensated phoria, we tested these interactions by comparing their accommodative responses to a 2.50‐D target under binocular fused conditions (BFC) and monocular occluded conditions (MOC). The accommodative response in BFC frequently differed from that in MOC. The magnitude of the accommodative errors in BFC, ranging from an accommodative lag of 1.80 D (in an esophoric patient) to an accommodative lead of 1.56 D (in an exophoric patient), was correlated with distance heterophoria and uncorrected refractive errors. These results indicate that heterophoria affects the accuracy of accommodation to various degrees, as the model predicted, and that an accommodative error larger than the depth of focus of the eye occurs in exchange for binocular single vision in some heterophoric patients.