People with convergence insufficiency might have otherwise normal vision, so it's important to mention reading or learning concerns to your eye care provider. To diagnose convergence insufficiency, your eye doctor might:
- Take a medical history. This might include questions about problems you have with focusing, blurred or double vision, headaches, and symptoms.
- Measure the near point of convergence (NPC). This test measures the distance from your eyes to where both eyes can focus without double vision. The examiner holds a small target, such as a printed card or penlight, in front of you and slowly moves it closer to you until either you have double vision or the examiner sees an eye drift outward.
- Assess positive fusional vergence (PFV). During this test, you're asked to read letters on an eye chart while looking through prism lenses. The examiner will note when you begin to have double vision.
- Perform a routine eye exam. If you have any other vision problems, such as nearsightedness, your eye doctor might conduct tests to assess the degree of the problem.