[Do prism corrections according to H.-J. Haase affect ocular prevalence?]

Area of Science:

• Ophthalmology and Optometry
• Binocular Vision and Visual Perception
• Neuroscience of Vision

Context:

• Associated phoria, a vergence error, is often corrected using prism lenses.
• Hans-Joachim Haase developed the prevalence test to assess and correct associated phoria.
• The prevalence test involves stereoscopic targets to evaluate binocular vision and eye alignment.

Purpose:

• To investigate the efficacy of spherical and prismatic corrections in reducing ocular prevalence.
• To compare subjective (oral description) and objective (drawing, computer-controlled alignment) methods for assessing visual perception.
• To evaluate the clinical utility of Haase's prevalence test for associated phoria correction.

Summary:

• A study on 19 subjects found that spherical and prismatic corrections did not consistently reduce ocular prevalence across group means.
• Objective methods (drawing, computer alignment) showed prevalence reduction in only two individuals, who also received refractive error correction.
• Subjective oral reports of equivalence often contradicted objective findings, suggesting potential biases in self-reporting.

Impact:

• The findings question the reliability of the prevalence test for correcting associated phoria.
• Discrepancies between subjective and objective assessments highlight the need for robust diagnostic tools in vision science.
• Results suggest that ocular prevalence is a common aspect of normal binocular vision, not always reducible by prisms.