Convergence Insufficiency Clinical Presentation
- Author: Michael J Bartiss, OD, MD; Chief Editor: Hampton Roy, Sr, MD more...
Patients typically present as teenagers or in early adulthood, complaining of gradually worsening eyestrain, periocular headache, blurred vision after brief periods of reading, and, sometimes, crossed diplopia with near work. It is not unusual for the patient to squint one eye while reading to relieve blurring or diplopia. Few, if any, symptoms are present at distance fixation. Symptoms are aggravated by illness, lack of sleep, anxiety, and prolonged near work. Left untreated, the exophoria at near may break down to a poorly controlled intermittent exotropia. Fortunately, in most cases, convergence insufficiency is very amenable to orthoptics and vision therapy.
The symptoms of convergence insufficiency are directly associated with reading or other close work visual demands. Many patients with objectively measured convergence insufficiency may not complain of symptoms. This usually occurs because of suppression of the nonfixating eye or avoidance of near vision tasks. The clinician should inquire about any such avoidance behavior in patients who are not experiencing any symptoms but who have clinical objective findings consistent with convergence insufficiency. The most common symptoms associated with convergence insufficiency include asthenopia (eyestrain) and headache, diplopia, blurred vision, and perceived moving of print when reading.
Asthenopia (eyestrain) and headache
These symptoms were clearly described by von Graefe as early as 1855. Classically, such symptoms occur after short periods of reading or other close work. This most frequently occurs due to the sustained increased effort required to increase fusional convergence.
Accommodative insufficiency is often associated with convergence insufficiency and symptoms of asthenopia and headache. This occurs as the patient tries to eliminate near vision diplopia by increasing accommodative effort. The increased accommodative effort results in increased convergence, which may be more than what is required for the near vision task, thereby resulting in an esophoria (as mentioned above). This also explains the frequent accompaniment of blurry vision and diplopia that occur with asthenopia and headache symptoms.
The diplopia that manifests in some patients with convergence insufficiency may subjectively present as two distinct images or just an overlap of two images (a "ghost" image.) This distinction may be difficult for the patient to decipher. Many patients describe their symptoms as "blurry" vision rather than "double" vision. Proper testing can distinguish the two entities fairly easily by testing for "blurry" vision during monocular visual acuity testing.
Patients with uncorrected hyperopia in excess of +5.00 diopters (D) may generate little or no accommodative effort at near.
Patients with mild-to-moderate myopia do not need to stimulate accommodation to see clearly at the near working distance in their uncorrected state. This lack of accommodative effort results in decreased accommodative convergence.
Patients with early treated presbyopia frequently demonstrate convergence insufficiency. The relief provided by plus lenses at near is thought to translate to an inappropriate abandonment of appropriate accommodative effort. This results in decreased accommodative convergence and the manifestation of an exophoria that previously was partially compensated by using accommodative convergence.
Some patients with convergence insufficiency do not have symptoms of diplopia despite an obvious exodeviation at near. This probably occurs because of suppression of the nonfixating eye.
Patients with uncorrected hyperopia in excess of +5.00 D may produce little or no accommodative effort at near. This lack of accommodative effort results in blurry near images.
Efforts to increase convergence through stimulation of accommodative convergence to eliminate diplopia can sometimes cause blurry vision by simultaneously producing blurred near vision via over-accommodation.
Moving of print
This occurs because of unstable binocular alignment relative to the near vision convergence demand. This usually occurs when the patient tries to engage and maintain sufficient fusional convergence to establish and maintain binocular vision.
The physical diagnosis of convergence insufficiency is based on the findings of a reduced convergence near-point along with decreased positive fusional convergence amplitudes at near.
Remote near point of convergence: Patients should be able to maintain binocular fixation on a fusional target as it is brought up to at least 5 inches from the tip of the nose.
Significant exophoria or intermittent exotropia at near: Rarely, patients are orthophoric or even exhibit a small degree of esophoria at near, but all have a remote near point of convergence.
Patients may demonstrate small-to-nonexistent exophoria at distance.
Patients may demonstrate reduced stereoacuity at near.
Normal near point of accommodation may be present in many patients.
The underlying cause(s) of convergence insufficiency are not clearly established. A significant exophoria at near with inadequate fusional convergence appears to be the primary underlying problem. Von Graefe, who first described the condition in 1855, believed that this condition was myogenic in etiology, but subsequent electromyographic work has failed to demonstrate support for this theory. A connection has been made between accommodative insufficiency and convergence insufficiency. Closed head trauma and lesions in the pretectal area of the brain have been associated with acquired convergence insufficiency. Lesions in the midbrain dorsal to the third cranial nerve nuclei may also cause convergence insufficiency with normal third nerve function.
Von Noorden GK. Binocular Vision & Ocular Motility: Theory & Management of Strabismus. 5th ed. Mosby-Year Book; 1995. 468-476.
Khawam E, Abiad B, Boughannam A, Saade J, Alameddine R. Convergence Insufficiency/Divergence Insufficiency Convergence Excess/Divergence Excess: Some Facts and Fictions. Case Rep Ophthalmol Med. 2015. 2015:680474. [Medline].
Danchaivijitr C, Kennard C. Diplopia and eye movement disorders. J Neurol Neurosurg Psychiatry. 2004 Dec. 75 Suppl 4:iv24-31. [Medline].
Harrison RL. Loss of fusional vergence with partial loss of accommodative convergence and accommodation following head injury. Binoc Vis. 1987. 2:93.
Brown B. The convergence insufficiency masquerade. Am Orthoptic J. 1990. 40:94-7.
Clark TY, Clark RA. Convergence Insufficiency Symptom Survey Scores for Reading Versus Other Near Visual Activities in School-Age Children. Am J Ophthalmol. 2015 Aug 12. [Medline].
Master CL, Scheiman M, Gallaway M, Goodman A, Robinson RL, Master SR, et al. Vision Diagnoses Are Common After Concussion in Adolescents. Clin Pediatr (Phila). 2015 Jul 7. [Medline].
Sreenivasan V, Bobier WR. Increased onset of vergence adaptation reduces excessive accommodation during the orthoptic treatment of convergence insufficiency. Vision Res. 2015 Jun. 111 (Pt A):105-13. [Medline].
Scheiman M, Rouse M, Kulp MT, Cotter S, Hertle R, Mitchell GL. Treatment of convergence insufficiency in childhood: a current perspective. Optom Vis Sci. 2009 May. 86(5):420-8. [Medline]. [Full Text].
Pediatric Eye Disease Investigator Group. Effectiveness of Home-Based Therapy for Symptomatic Convergence Insufficiency. pedig.jaeb.org. Available at http://pedig.jaeb.org/Studies.aspx?RecID=205. Accessed: April 18, 2013.
Hermann JS. Surgical therapy of convergence insufficiency. J Pediatr Ophthalmol Strabismus. 1981 Jan-Feb. 18(1):28-31. [Medline].
Nemet P, Stolovitch C. Biased Resection of the Medial Recti: A New Surgical Approach to Convergence Insufficiency. 1990. Vol 5: 213.
Alvarez TL. A pilot study of disparity vergence and near dissociated phoria in convergence insufficiency patients before vs. after vergence therapy. Front Hum Neurosci. 2015. 9:419. [Medline].
Wallace DK. Treatment options for symptomatic convergence insufficiency. Arch Ophthalmol. 2008 Oct. 126(10):1455-6. [Medline].
Borsting EJ, Rouse MW, Mitchell GL, Scheiman M, Cotter SA, Cooper J, et al. Validity and reliability of the revised convergence insufficiency symptom survey in children aged 9 to 18 years. Optom Vis Sci. 2003 Dec. 80(12):832-8. [Medline].