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Management of patients with small-angle esotropia and subnormal stereopsis using Fresnel prism



Monofixation syndrome (MFS) is a specific subnormal binocular vision status, either with or without a small deviation. Patients with MFS have a tendency to maintain stable ocular alignment. Correction of refractive errors and occlusion are considered as treatment option for amblyopia, and the status of MFS could be changed with long-term follow-up. The purpose of this study is to evaluate whether a Fresnel prism affected the visual acuity, angle of deviation, and sensory status in small-angle esotropia with subnormal stereopsis presenting with MFS features.


Patients with small-angle esotropia within 8 prism diopters (PD) on the simultaneous prism and cover test from 2010 to 2019 were reviewed. Patients with subnormal stereopsis defined as more than 100 s of arc (arcsec) and with the central suppression with peripheral fusion were only included. A Fresnel prism was applied to the dominant eye, and the minimum follow-up period after Fresnel prism treatment was 24 months. We assessed patient clinical characteristics, course and response to therapy including visual acuity, angle of deviation, and stereopsis.


Twenty patients with a mean age of 5.5 ± 1.4 years were included. The mean duration of Fresnel prism treatment was 15.3 ± 10.3 months. After 50.7 ± 17.2 months of follow-up, VA of the non-dominant eye was changed from 0.26 ± 0.20 logMAR to 0.07 ± 0.17 logMAR (P < .001). The initial stereoacuities were 3.54 ± 0.27 log arcsec, ranged from 6000 to 400 arcsec. After the treatment with Fresnel prism, the final stereoacuities were 3.09 ± 0.58 log arcsec, ranged from 6000 to 100 arcsec (P = .001); nine patients (45%) improved stereoacuity more than two octaves. No changes in the angle of deviation or a change of fixation were observed.


After use of Fresnel prism, there was some improvement in visual acuity and stereopsis in patients with MFS features. Following occlusion and refractive correction, management using Fresnel prism could be attempted in small-angle esotropic patients with amblyopia or subnormal stereopsis.

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  1. Parks MM (1969) The monofixation syndrome. Trans Am Ophthalmol Soc 67:609–657

    PubMed  PubMed Central  CAS  Google Scholar 

  2. Eom Y, Kim SH, Kim SW, Cho YA (2013) Applicability of scanning laser ophthalmoscopy microperimetry on the fixation patterns of monofixation syndrome. Can J Ophthalmol 48:413–419.

    Article  PubMed  Google Scholar 

  3. Marie C, Charlotte AH, Robert MM, Gordon ND (1998) Recovery in microtropia implications for aetiology and neurophysiology. Br J Ophthalmol 82:225–231.

    Article  Google Scholar 

  4. Houston CA, Cleary M, Dutton GN, McFadzean RM (1998) Clinical characteristics of microtropia - is microtropia a fixed phenomenon? Br J Ophthalmol 82:219–224.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  5. Lee HJ, Kim SJ, Yu YS (2017) Stereopsis in patients with refractive accommodative esotropia. J AAPOS 21:190–195.

    Article  PubMed  Google Scholar 

  6. Holmes JM, Kraker RT, Beck RW, Birch EE, Cotter SA, Everett DF, Hertle RW, Quinn GE, Repka MX, Scheiman MM, Wallace DK (2003) A randomized trial of prescribed patching regimens for treatment of severe amblyopia in children. Ophthalmology 110:2075–2087.

    Article  PubMed  Google Scholar 

  7. Repka MX, Beck RW, Holmes JM, Birch EE, Chandler DL, Cotter SA, Hertle RW, Kraker RT, Moke PS, Quinn GE, Scheiman MM (2003) A randomized trial of patching regimens for treatment of moderate amblyopia in children. Arch Ophthalmol 121:603–611.

    Article  PubMed  Google Scholar 

  8. Wallace DK, Lazar EL, Holmes JM, Repka MX, Cotter SA, Chen AM, Kraker RT, Beck RW, Clarke MP, Lorenzana IJ, Petersen DB, Roberts JT, Suh DW (2013) A randomized trial of increasing patching for amblyopia. Ophthalmology 120:2270–2277.

    Article  PubMed  Google Scholar 

  9. Adams WE, Leske DA, Hatt SR, Holmes JM (2009) Defining real change in measures of stereoacuity. Ophthalmology 116:281–285.

    Article  PubMed  Google Scholar 

  10. Lang J (1983) Microtropia. Int Ophthalmol 6:33–36.

    Article  PubMed  CAS  Google Scholar 

  11. Arthur BW, Smith JT, Scott WE (1989) Long-term stability of alignment in the monofixation syndrome. J Pediatr Ophthalmol Strabismus 26:224–231

    Article  CAS  Google Scholar 

  12. Ing MR, Roberts KM, Lin A, Chen JJ (2014) The stability of the monofixation syndrome. Am J Ophthalmol 157:248-253.e241.

    Article  PubMed  Google Scholar 

  13. Siatkowski RM (2011) The decompensated monofixation syndrome (an American Ophthalmological Society thesis). Trans Am Ophthalmol Soc 109:232–250

    PubMed  PubMed Central  Google Scholar 

  14. Hunt MG, Keech RV (2005) Characteristics and course of patients with deteriorated monofixation syndrome. J AAPOS 9:533–536.

    Article  PubMed  Google Scholar 

  15. Houston CA, Cleary M, Dutton GN, McFadzean RM (1998) Clinical characteristics of microtropia–is microtropia a fixed phenomenon? Br J Ophthalmol 82:219–224.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  16. Wilson ME, Bluestein EC, Parks MM (1993) Binocularity in accommodative esotropia. J Pediatr Ophthalmol Strabismus 30:233–236

    Article  CAS  Google Scholar 

  17. Mulvihill A, MacCann A, Flitcroft I, O’Keefe M (2000) Outcome in refractive accommodative esotropia. Br J Ophthalmol 84:746–749

    Article  CAS  Google Scholar 

  18. Leske DA, Holmes JM (2004) Maximum angle of horizontal strabismus consistent with true stereopsis. J AAPOS 8:28–34.

    Article  PubMed  Google Scholar 

  19. Wong AM, Lueder GT, Burkhalter A, Tychsen L (2000) Anomalous retinal correspondence: neuroanatomic mechanism in strabismic monkeys and clinical findings in strabismic children. J AAPOS 4:168–174

    Article  CAS  Google Scholar 

  20. Birch EE, Gwiazda J, Held R (1982) Stereoacuity development for crossed and uncrossed disparities in human infants. Vision Res 22:507–513

    Article  CAS  Google Scholar 

  21. Birch EE, Morale SE, Jeffrey BG, O’Connor AR, Fawcett SL (2005) Measurement of stereoacuity outcomes at ages 1 to 24 months: Randot Stereocards. J AAPOS 9:31–36.

    Article  PubMed  Google Scholar 

  22. Birch EE (2003) Marshall Parks lecture. Binocular sensory outcomes in accommodative ET. J AAPOS 7:369–373.

    Article  PubMed  Google Scholar 

  23. Birch EE, Stager DR Sr, Berry P, Leffler J (2004) Stereopsis and long-term stability of alignment in esotropia. J AAPOS 8:146–150.

    Article  PubMed  Google Scholar 

  24. Savino G, Abed E, Rebecchi MT, Spreca M, Tredici C, Dickmann A (2016) Acute acquired concomitant esotropia and decompensated monofixation syndrome: a sensory-motor status assessment. Can J Ophthalmol 51:258–264.

    Article  PubMed  Google Scholar 

  25. Parks MM (1975) Monofixation syndrome: a frequent end stage of strabismus surgery. Trans Sect Ophthalmol Am Acad Ophthalmol Otolaryngol 79:733–735

    PubMed  CAS  Google Scholar 

  26. Hatt SR, Leske DA, Mohney BG, Brodsky MC, Holmes JM (2010) Classification and misclassification of sensory monofixation in intermittent exotropia. Am J Ophthalmol 150:16–22.

    Article  PubMed  PubMed Central  Google Scholar 

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This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MOE) (No. 2021R1G1A10009844), and by research funds for newly appointed professors of Jeonbuk National University in 2020. The sponsor or funding organization had no role in the design or conduct of this research.

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Correspondence to Seong-Joon Kim.

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For this type of study, formal consent is not required. The Institutional Review Board of Seoul National University Hospital in South Korea granted a waiver of consent for this retrospective chart review study.

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Lee, HJ., Kim, SJ. Management of patients with small-angle esotropia and subnormal stereopsis using Fresnel prism. Graefes Arch Clin Exp Ophthalmol 260, 345–352 (2022).

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  • Fresnel prism
  • Stereopsis
  • Esotropia
  • Amblyopia
  • Monofixation syndrome