Brewster near: The ortho separation is which value?

Brewster near: The ortho separation is which value?

• A. 87 mm
• B. 68 mm
• C. 58 mm
• D. 63 mm

Answer: (D)

The main idea here is the distance between the two visual axes when looking at a near target, called the near interpupillary distance (near PD) or ortho separation. In someone with normal binocular alignment (orthophoria), the separation of the eyes’ lines of sight at near roughly matches their near PD. The Brewster near method is a practical way to estimate this separation by using corneal reflections as references while the patient fixates a near target. For adults, near PD typically falls in the low 60s of millimeters, around 63 mm. That makes 63 mm the best match for the ortho separation at near, since it aligns with the common near PD value. The other options are further from the usual range for near PD and are less likely to represent the normal ortho separation.

The main idea here is the distance between the two visual axes when looking at a near target, called the near interpupillary distance (near PD) or ortho separation. In someone with normal binocular alignment (orthophoria), the separation of the eyes’ lines of sight at near roughly matches their near PD. The Brewster near method is a practical way to estimate this separation by using corneal reflections as references while the patient fixates a near target.

For adults, near PD typically falls in the low 60s of millimeters, around 63 mm. That makes 63 mm the best match for the ortho separation at near, since it aligns with the common near PD value. The other options are further from the usual range for near PD and are less likely to represent the normal ortho separation.