The near point of convergence refers to the closest point at which the eyes can comfortably focus on an object. In phonetic terms, it is spelled as /nɪə pɔɪnt əv kənˈvɜːdʒəns/. The word "near" is pronounced with a short "i" sound followed by the vowel "uh". The word "point" is pronounced as /pɔɪnt/ with an open "o" sound followed by the consonant cluster "nt". The word "of" is pronounced as /əv/ with an unstressed vowel and the word "convergence" is pronounced as /kənˈvɜːdʒəns/ with the consonant cluster "nv" and the vowel "uh" followed by the stressed vowel "er".
The near point of convergence refers to the closest distance an individual can focus on an object or target positioned in front of them. It is a fundamental measurement used in optometry and ophthalmology to assess the coordination and flexibility of the eye muscles responsible for near vision focusing.
Typically, the near point of convergence is determined by instructing the person to fixate on an object, such as a pencil tip, held directly in front of them. As the object is gradually moved closer towards the person's nose, there comes a point where they can no longer maintain clear and single vision. At this point, the examiner measures the distance between the object and the person's eyes, which represents their near point of convergence.
The near point of convergence is an essential test for detecting certain visual disorders, particularly those related to eye muscle imbalances or weaknesses. Conditions such as convergence insufficiency, where the eyes have difficulty coming together to focus on near objects, may be determined using this measurement. Additionally, it helps in diagnosing other visual problems like strabismus (ocular misalignment) or accommodative infacility (difficulty with focusing).
In summary, the near point of convergence represents the closest distance a person can comfortably focus on a target or object while maintaining clear and single vision. This measurement plays a crucial role in the assessment of visual coordination and muscle strength, aiding in the diagnosis and treatment of various eye-related conditions.
The point to which the visual lines are directed when c. is at its maximum.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.