Comparing proximal convergence ratio in myopes.

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Myopia, a common refractive error, can influence binocular vision parameters.
• The proximal convergence to accommodation ratio (PC/A) and accommodative convergence to accommodation ratio (AC/A) are key metrics in assessing visual function.
• Understanding these ratios in different myopia severities is crucial for clinical management.

Purpose of the Study:

• To investigate potential differences in the PC/A ratio between two distinct groups of myopic patients.
• To compare PC/A in low-to-moderate myopia (Group A: -0.50D to -3.00D SE) versus high myopia (Group B: > -3.00D SE).

Main Methods:

• A prospective observational study involving 24 patients in Group A and 27 in Group B.
• Exclusion criteria included pathological myopia, strabismus, or heterophoria.
• PC/A was calculated using the difference between AC/A (derived from heterophoria and gradient methods) and a prism bar method.

Main Results:

• Group B (high myopia) exhibited a significantly higher average PC/A ratio (3.24∆/D) compared to Group A (low-to-moderate myopia) (2.6∆/D) (p < 0.05).
• The findings indicate a statistically significant difference in PC/A between the two myopia groups.

Conclusions:

• High myopia (>-3.00D SE) is associated with an elevated PC/A ratio.
• A high AC/A ratio appears to be the primary factor contributing to the increased PC/A observed in patients with high myopia.