purpose: to determine stereopsis with local (titmus) and global (tno) tests in symptomatic and asymptomatic subjects according to induced disparity (crossed or uncrossed). methods: in this cross sectional study, 80 students of zahedan university of medical sciences who fulfilled the inclusion criteria were randomly selected. at first, refractive error was determined by retinoscopy and then base...

In heterophoria there is a relative deviation of the visual axes held in check by the fusion mechanism, whereas in heterotropia there is a manifest deviation of the visual axes. The relative position of the visual axes is determined by the equilibrium or disequilibrium of forces that keep the eyes properly aligned and of forces that disrupt this alignment. Clearly, the fusion mechanism and its ...

Fixation disparity is a minute ocular misalignment under conditions of binocular single vision and is typically detected in primary eye care practices in the UK using the Mallett Unit Fixation Disparity Test. This instrument creates natural viewing conditions, when the patient's binocular system is fused using both central and peripheral fusion locks. This allows the examiner to determine the m...

AIMS To establish the prevalence of heterophoria and its association with refractive error and ethnicity in a population-based study of Australian schoolchildren. METHODS The Sydney Myopia Study is a stratified, random cluster (school-based) sample of 4093 students (examined: 2003-2005). Two samples aged 6 (n=1692) and 12 years (n=2289) without heterotropia were included. Prevalent heterophoria...