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Exophoria is a type of heterophoria characterized by a tendency for outward deviation of the eyes from the standard visual axis. In the majority of cases, it arises due to convergence insufficiency or inability to maintain proper eye alignment at near vision and the cause is unknown.


Apart from visual observation of the tendency of the eyes to drift outward, symptoms are frequently absent [1], but when it is a constitutive feature of convergence insufficiency (CI), defined as inability to preserve normal eye alignment at near, it can present with symptoms such as eye fatigue, headaches, and double vision when attempting to perform activities that require near sight, for e.g. reading [2] [3]. CI, apart from exophoria, can be accompanied by a remote near point of convergence or decreased positive fusional vergence [3] [4]. Other symptoms that are reported in patients suffering from exophoria are the frequent loss of place when reading, print moving on the page, difficulty concentrating and a short attention span [2]. In some cases, hyperphoria - a permanent upward deviation of the visual axis of the eye, was described as well [5]. Some authors consider that severe exophoria progressively leads to intermittent exophoria, a type of strabismus and that it may develop as early as infancy [1].

  • H50.61 Brown's sheath syndrome H50.69 Other mechanical strabismus H50.8 Other specified strabismus Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.[icd10data.com]
  • This form of strabismus is easily detected through an eye examination, and we pediatric ophthalmologists actively screen for it in our patients. For some people this strabismus is merely an incidental eye finding, and there are no symptoms.[hutchdoc.com]
  • 15th Jun 2009, 20:14 Thread Starter Join Date: Jun 2009 Location: United Kingdom Age: 39 Posts: 23 Exophoria and Exotropia and Strabismus- Aren't they the same?! Hello to you all!, Hope you are all well... Exophoria and Exotropia and Strabismus.[pprune.org]
Retinal Damage
  • However, even a mild phoria can create significant problems with fusion when you add mild retinal damage (making the images in each eye slightly different in size/shape) and differences in refractive error between the eyes (creating a difference in image[medhelp.org]
Scintillating Scotoma
  • scotoma Pupil Anisocoria Argyll Robertson pupil Marcus Gunn pupil Adie syndrome Miosis Mydriasis Cycloplegia Parinaud's syndrome Other Nystagmus Childhood blindness Infections Trachoma Onchocerciasis Index of the eye Description Phenomena Disease Treatment[worldlibrary.org]
Ectopia Lentis
  • lentis Retina Retinitis Chorioretinitis Cytomegalovirus retinitis Retinal detachment Retinoschisis Ocular ischemic syndrome / Central retinal vein occlusion Central retinal artery occlusion Retinopathy diabetic hypertensive Purtscher's of prematurity[worldlibrary.org]
Red Eye
  • eye Keratomycosis Phthisis bulbi Persistent fetal vasculature / Persistent hyperplastic primary vitreous Persistent tunica vasculosa lentis Familial exudative vitreoretinopathy Pathways Optic nerve Optic disc Optic neuritis optic papillitis Papilledema[worldlibrary.org]


Physicians can make a preliminary diagnosis just by close inspection of the eyes during the physical examination, while patient history can reveal signs and symptoms that indicate problems with near vision. Some tests, however, may be employed to confirm exophoria as the cause of symptoms. Firstly, simple cover testing and evaluation of accommodation can be performed, which will provoke the outward movement of the eye in virtually all cases. The Snellen chart should not be used as a sole diagnostic method, since it may reveal completely normal findings in patients suffering from exophoria. The severity of prism diopter (PD) deviation should be examined by skilled ophthalmologists, in order to evaluate the need for correction [3].


  • Treatment of Convergence Insufficiency Treatments for CI can be categorized as active or passive: Active treatment : A multi-site randomized clinical trial funded by the National Eye Insitute has proven that the best treatment for convergence insufficiency[convergenceinsufficiency.org]
  • Treatment of exophoria is primarily nonsurgical. Treatment is primarily treatment of fusion. If fusion can be strengthened, or demands on it lessened, the patient can be helped.[healio.com]
  • In the case of reoccurrence, treatments will again correct the condition.[healthline.com]


  • The conclusions drawn from his data are: A high AC/A is an indicator of a poor surgical prognosis and most of these patients have a consecutive esotropia at near. Tenacious proximal fusion is an indicator of a good surgical prognosis.[eyerounds.org]
  • Tenacious proximal fusion is an indicator of a good surgical prognosis.[eyewiki.aao.org]


  • Keywords: accommodation • vergence • strabismus: etiology 2011, The Association for Research in Vision and Ophthalmology, Inc., all rights reserved.[iovs.arvojournals.org]
  • […] myopia as the sole cause of exophoria Baum [8] also reported that myopia cannot be held responsible for exophoria Pascal [9] was of the view that exophoria is almost always secondary to myopia Recently Burian [10] stated that the role of myopia in the etiology[ijo.in]
  • Genetics and Risk factors Although heredity appears to play a role in exodeviations, the etiology of this disorder is probably multifactorial. A positive family history is often noticed (18).[eyerounds.org]
  • Clinical Characteristics Genetics and Risk factors Although heredity appears to play a role in exodeviations, the etiology of this disorder is thought to be multifactorial.[eyewiki.aao.org]
  • When patients report diplopia, particularly if recent in onset, you must first rule out potentially life-threatening etiologies.[reviewofoptometry.com]


  • Secondary Form The epidemiology of primary and secondary form appears similar, with highest incidence among adults, but pediatric cases are reported sporadically as well.[reviewofophthalmology.com]
  • EPIDEMIOLOGY Variable incidence Affects 2.25-8.3% of population Bimodal peak incidence at High school or college age, when there is an increased demand for near work Early middle age, secondary to initiation of bifocal use and decreased accommodative[webeye.ophth.uiowa.edu]
Sex distribution
Age distribution


  • Pathophysiology of exodeviation. In: symposium on horizontal ocular deviation. St. Louis, Ed. Manley DR. 1971 Mosby-Year Book, Inc., pg 119 Costenbader FD. The physiology and management of divergent strabismus.[eyerounds.org]
  • Pathophysiology of exodeviation. In: symposium on horizontal ocular deviation. St. Louis, Ed. Manley DR. 1971 Mosby-Year Book, Inc., pg 119 9.0 9.1 Costenbader FD. The physiology and management of divergent strabismus.[eyewiki.aao.org]


  • Neuro-ophthalmological examination at an earlier stage could have prevented unnecessary neuroimaging and botulin injections.[bjo.bmj.com]
  • AME is still directed not to withhold the medical certificate as outlined below: Guide for Aviation Medical Examiners Referencing the FARs, the applicable section is Part 67.103(f): (f) Bifoveal fixation and vergence-phoria relationship sufficient to prevent[forums.jetcareers.com]
  • The symptoms I have obviously bother me, and I would consider this option to rid myself of them if therapy/prevention did not work.[medhelp.org]
  • Preventive treatment of "phorias" in the young requires attention to refraction and prism needs as well as attention to medical or psychological problems. 5.[healio.com]



  1. Jung JW, Lee SY. A Comparison of the Clinical Characteristics of Intermittent Exotropia in Children and Adults. Korean J Ophthalmol. 2010;24(2):96–100.
  2. Saunte JP, Holmes JM. Sustained improvement of reading symptoms following botulinum toxin A injection for convergence insufficiency. Strabismus. 2014;22(3):95-99.
  3. Bade A, Boas M, Gallaway M, et al. Relationship between Clinical Signs and Symptoms of Convergence Insufficiency. Optom Vis Sci. 2013;90(9):988-995.
  4. Scheiman M, Gwiazda J, Li T. Non-surgical interventions for convergence insufficiency. Cochrane Database Syst Rev. 2011;(3):CD006768.
  5. Gupta NC, Narang RK, Khurana AK, Parmar IP, Ahluwalia BK. Exophoria and refractive errors-evaluation of 250 cases. Indian J Ophthalmol. 1987;35(4):204-206.

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Last updated: 2019-07-11 22:39