• Users Online: 5728
  • Home
  • Print this page
  • Email this page

   Table of Contents      
Year : 2013  |  Volume : 61  |  Issue : 2  |  Page : 82

Synergistic convergence and substituted convergence

1 Department of Ophthalmology, Selcuk University Selcuklu Medical Faculty, Konya, Turkey
2 Neuro-Ophthalmology Unit, Hacettepe University, Institute of Neurological Sciences, Ankara, Turkey

Date of Web Publication15-Feb-2013

Correspondence Address:
Berker Bakbak
Department of Ophthalmology, Selcuk University Selcuklu Faculty of Medicine, Konya
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0301-4738.107204

Rights and Permissions

How to cite this article:
Bakbak B, Kansu T. Synergistic convergence and substituted convergence. Indian J Ophthalmol 2013;61:82

How to cite this URL:
Bakbak B, Kansu T. Synergistic convergence and substituted convergence. Indian J Ophthalmol [serial online] 2013 [cited 2023 Dec 9];61:82. Available from: https://journals.lww.com/ijo/pages/default.aspx/text.asp?2013/61/2/82/107204

Dear Editor,

Jain et al. [1] described two intriguing cases with horizontal gaze palsy and progressive scoliosis. In the article, bilateral adduction on attempted lateral gaze was referred to by the term 'synergistic convergence'.

Bilateral deficit of abduction associated with simultaneous bilateral adduction on attempted lateral gaze has been previously referred to in different terms, including 'synergistic convergence' and 'substituted convergence'. [2],[3],[4] Synergistic convergence, the term used when miosis is not present during convergence on attempted lateral gaze, has been related to peripheral causes, such as, congenital fibrosis of extraocular muscles, ocular misinnervation, or rarely, central causes like horizontal gaze palsy with progressive scoliosis, and brain stem dysplasia. [2] The term 'substituted convergence' has been used in earlier case reports for a convergence movement accompanied by miosis on attempted lateral gaze, in patients with pontine, cerebellar or posterior fossa lesions, and brain stem maldevelopments. [3]

Presence of miosis during lateral gaze, in patients with simultaneous bilateral adduction on an attempted lateral gaze, is important for distinguishing the mechanism of this abnormal ocular movement. In the report of Jain NR et al., [1] pupillary response to the lateral gaze in case 2 should have been pointed out, in order to understand the mechanism and to use the term 'synergistic convergence'.

The mechanism of synergistic convergence is controversial. Khan et al. [2] found normal convergence with appropriate miosis in their patient, whereas, miosis did not accompany convergence during attempted horizontal gaze; therefore, he pointed out discrete neuroanatomic localization of the three components of near triad (convergence, miosis, and accommodation). The significance of synergistic convergence was the rare glimpse of vergence dissociated from miosis, which suggested a more peripheral localization, selectively affecting vergence without pupillary involvement compared to substitution convergence.

The mechanism of substituted convergence is also controversial. Leigh and Zee [4] offered a mechanism for this abnormal ocular movement in the setting of horizontal gaze, suggesting synchronized coexistance of the vergence and version system in conjugate eye movement. Lesioning of the version system can result in overactivity of the convergence system. The mechanism of convergence substitution in cases with horizontal gaze palsy with progressive scoliois (HGPPS) may be different from cases with acute pontine lesions, as presumably there is no acute disruption or injury to the underlying circuitry that is intact in convergence, but aberrant in conjugate horizontal gaze in HGPPS. The presence of miosis during lateral gaze suggests the use of the full vergence system in the absence of the version system to assist the limited gaze (adaptive phenomenon). Also, checking the amount of accommodation (myopic refractive error shifts) during substituted convergence movements should also have been determined, to confirm the use of convergence in these cases.

In conclusion, the terms 'synergistic' or 'substituted' convergence should be used separately and further observations are needed to clarify the pathomechanism of those paradoxical eye movements in patients with HGPPS.

  References Top

Jain NR, Jethani J, Narendran K, Kanth L. Synergistic convergence and split pons in horizontal gaze palsy and progressive scoliosis in two sisters. Indian J Ophthalmol 2011;59:162-5.  Back to cited text no. 1
[PUBMED]  Medknow Journal  
Khan AO, Oystreck DT, Al-Tassan N, Al-Sharif L, Bosley TM. Bilateral synergistic convergence associated with homozygous ROB03 mutation (p. Pro 771 Leu). Ophthalmology 2008;115:2262-5.  Back to cited text no. 2
Bosley TM, Salih MA, Jen JC, Lin DD, Oystreck D, Abu-Amero KK, et al. Neurologic features of horizontal gaze palsy and progressive scoliosis with mutations in ROBO3. Neurology 2005;64:1196-203.  Back to cited text no. 3
Leigh RJ, Zee DS. Vergence system. In: Leigh RJ, Zee DS, editors. In The Neurology of Eye Movements. Oxford: University Press; 2006. p. 356-7.  Back to cited text no. 4

This article has been cited by
1 Regional Differences and Convergence of Urban-Rural Integration Development from the Perspective of Factor Flow
Li Qian, Ke Zhang, Jun-Xiu Song, Wei-Yi Tang, Hanliang Fu
Journal of Environmental and Public Health. 2022; 2022: 1
[Pubmed] | [DOI]
2 Variant types of Duane retraction syndrome: synergistic divergences and convergences
Tao Shen, Ying Kang, Daming Deng, Zhonghao Wang, Xuan Qiu, Jianhua Yan
Journal of American Association for Pediatric Ophthalmology and Strabismus. 2021; 25(1): 14.e1
[Pubmed] | [DOI]
3 Near Reflex Substitution for Horizontal Gaze Palsy in a Patient With Facial Colliculus Syndrome
Mohadaseh Feizi, Abbas Bagheri, Zahra Latifi, Mehdi Tavakoli
Journal of Pediatric Ophthalmology & Strabismus. 2020; 57(6)
[Pubmed] | [DOI]
4 Changing paradigms of anti-VEGF in the Indian scenario
Shanmugam, P.M.
Indian Journal of Ophthalmology. 2014; 62(1): 88-92
5 Infantile esotropia with cross-fixation, inability to abduct, and underlying horizontal gaze palsy with progressive scoliosis
Berker Bakbak,Tulay Kansu
Journal of American Association for Pediatric Ophthalmology and Strabismus. 2014;
[Pubmed] | [DOI]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article

 Article Access Statistics
    PDF Downloaded189    
    Comments [Add]    
    Cited by others 5    

Recommend this journal