Title: To Study the Prevalence of Convergence Insufficiency: A Hospital Based Study
Authors: Dr Sakshi Sahni, Dr Abhishek Sachdeva, Dr Nalini Birpuri
DOI: https://dx.doi.org/10.18535/jmscr/v9i12.39
Abstract
Introduction
Convergence insufficiency (CI) is a binocular vision disorder characterized by difficulty in maintaining fusion while looking at a near target due to a tendency of the eyes to drift outwards. Exophoria that is greater at near than at distance, a remote near point of convergence(NPC), or decreased insufficiency is a common non-strabismic binocular vision disorder and is associated with symptoms such as headache, watering from eyes, visual fatigue and blurring of vision especially on near work. Earlier convergence insufficiency was defined as receding near point of convergence (NPC). Convergence insufficiency may be said to exist when the near point of convergence : more than 11 cm from the inter-ocular base line or 9.5 cm from the apex of cornea or when there is difficulty in attaining 30° convergence.(Duke-Elder 1973). convergence insufficiency (Scheiman, Wick 2002 ) is a condition in which there is -
- Exophoria at near;
- Orthophoria or low exophoria at distance;
- Receded near point of convergence;
- Reduced positive fusional vergence (PFV);
- Low AC/A ratio.
References
- Borsting E, Rouse MN, De Land, PN, Convergence Insufficiency and Reading Studies”(CIRS) group: prospective of convergence insufficiency and normal binocular children on CIRS symptom survey.Optom Vis Sci 1999;70:221-8.
- Borsting E, Rouse MN, Scheiman M et al Conveergence Insufficiency and treatment trial group: Validity and Reliability of revised convergence insufficiency symptom survey in children aged 9 to 18 years. Optom Vis Sci 2003;80:832-838.
- Brinkley JR Jr, Walonker F: convergence amplitude insufficiency. Ann Opthalmol1983;15:826-8,830-1.
- Duke –Elder S, Wybar K: System of Ophthalmology. 1970;Vol 6 :169-70, 562-70.
- Granet DG: Quoted in meeting of American Academy of paediatric Ophthalmology,San Diego.2004.
- Kanski JJ: Clinical Ophthalmology- A Systematic approach, 5th 2003: 520.
- Porcar E, Martinez - Palomera A: Prevalence of general binocular dysfunction in a population of university students.Optom Vis sci 1997;74:111-3.
- Scheiman M, Gallaway M et al: prevalence of vision and ocular conditions in a clinical paediatric population. J Am Optom Assoc 1996;67:193-202.
- Von Noorden GK, Campos EC: Binocular vision and ocular motility-Theory and management of strabismus.2002;6th ed:85-99,502-505.
- Wick B, Bedell H: Magnitude and velocity of proximal convergence. Invest Ophthalmol Vis Sci 1989;30: 755.