Methods of Determining the Amount of Prism Prescription in Heterophoria

Ejike; Thaddaeus Chukwudi; Ubani; Udo Ahanna; Onyekwere; Ike Francis; Dania; Afe Victor

doi:10.56201/ijmepr.v9.no6.2025.pg27.36

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Methods of Determining the Amount of Prism Prescription in Heterophoria

Ejike, Thaddaeus Chukwudi, Ubani, Udo Ahanna, Onyekwere, Ike Francis, and, Dania, Afe Victor

Abstract

Heterophoria, a latent ocular misalignment, can lead to significant visual discomfort when it decompensates, often manifesting as eyestrain, headaches, diplopia, and reading difficulties. Prism prescription remains a central approach to managing symptomatic heterophoria by alleviating fusional vergence stress. However, the amount of prism to prescribe remains a subject of clinical debate, with several methods available—each differing in theoretical basis, application, and effectiveness. This systematic review aims to identify, describe, and compare the various clinical methods for determining the appropriate amount of prism in heterophoria management, and to evaluate their accuracy, clinical utility, and impact on patient outcomes. A comprehensive literature search was conducted across PubMed, Scopus, Web of Science, CINAHL, and PsycINFO for studies published between 1980 and 2025. Inclusion criteria targeted peer-reviewed studies involving prism prescribing strategies for heterophoria. Studies were screened, selected, and assessed for quality using PRISMA guidelines and appropriate bias assessment tools. Key methods reviewed include Sheard’s criterion, Percival’s criterion, associated phoria tests (e.g., Mallett unit), fixation disparity assessments, and other subjective and objective approaches. The review highlights that while objective criteria like Sheard’s and Percival’s offer structured calculations, they may not always align with patient symptomatology. Subjective approaches such as associated phoria and fixation disparity testing are more reflective of individual visual comfort and are often preferred in practice. Each method has distinct strengths and limitations concerning reliability, patient satisfaction, and long-term success. There is no universally superior method for prescribing prism in heterophoria. Clinical decisions should be individualized, integrating both objective findings and subjective responses. Fut

Keywords

strategiesusing Boolean operators (ANDOR). The following search string was adapted for each

References

1. Rouse MW, Hyman L, Hussein M, Solan H, Reinstein L, Wold R. Frequency of convergence insufficiency among fifth and sixth graders. Optometry and Vision Science. 1998;75(8):517–522. https://doi.org/10.1097/00006324-199808000-00002 Pickwell LD, Jenkins TCA, Yekta AA. The effect on fixation disparity and associated heterophoria of reading at an intermediate distance. Ophthalmic and Physiological Optics. 1987;7(4):345–349. https://doi.org/10.1111/j.1475-1313.1987.tb00865.x Evans BJW. Pickwell’s binocular vision anomalies: Investigation and treatment. 4th ed. Oxford: Butterworth-Heinemann; 2002. Cooper J, Jamal N. Assessing fixation disparity and associated phoria: A clinical approach. Optometry and Vision Development. 2012;43(2):64–72. Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Medicine. 2009;6(7):e1000097. https://doi.org/10.1371/journal.pmed.1000097 Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, Shamseer L, Tetzlaff JM, Akl EA, Brennan SE, Chou R, Glanville J, Grimshaw JM, Hróbjartsson A, Lalu MM, Li T, Loder EW, Mayo-Wilson E, McDonald S, Moher D. The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. https://doi.org/10.1136/bmj.n71 Wells GA, Shea B, O’Connell D, Peterson J, Welch V, Losos M, Tugwell P. The Newcastle- Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses. Ottawa Hospital Research Institute. http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp Sheard C. Zones of ocular comfort. American Journal of Optometry and Archives of American Academy of Optometry. 1930;7(1):9–25. Wick B. Vergence disorders. In: Benjamin WJ, editor. Borish’s clinical refraction. 2nd ed. Oxford: Elsevier; 2006. p.1047–1120. Percival AH. The prescribing of spectacles. 4th ed. Bristol: John Wright & Sons Ltd; 1928. Evans BJW. Pickwell’s binocular vision anomalies. 5th ed. Oxford: Elsevier; 2007. Karania R, Evans BJW. The Mallett fixation disparity test: Influence of test instructions and relationship with symptoms. Ophthalmic and Physiological Optics. 2006;26(5):507–522. https://doi.org/10.1111/j.1475-1313.2006.00387.x Ogle KN. Researches in binocular vision. Philadelphia: W.B. Saunders; 1950. Hrynchak PK, Herriot C. The use of fixation disparity measures in clinical practice. Optometry and Vision Science. 1994;71(5):332–338. O’Leary CI, Evans BJW. Criteria for prescribing optometric interventions: Literature review and practitioner survey. Optometry and Vision Science. 2003;80(11):740–749. https://doi.org/10.1097/00006324-200311000-00011 Grisham JD. Visual therapy results for convergence insufficiency: A literature review. American Journal of Optometry and Physiological Optics. 1996;73(7):512–520. https://doi.org/10.1097/00006324-199607000-00007 Evans BJW. Pickwell’s binocular vision anomalies. 5th ed. Oxford: Butterworth-Heinemann; Joosse MV, Simonsz HJ, de Jong PTVM. Repeatability of fixation disparity measurements. Graefe's Archive for Clinical and Experimental Ophthalmology. 2000;238(2):104–110. https://doi.org/10.1007/s004170050017 North RV, Henson DB, Bremner MH. The use of the prism adaptation test in the investigation of patients with decompensated heterophoria. Ophthalmic and Physiological Optics. 1993;13(3):223–226. https://doi.org/10.1111/j.1475-1313.1993.tb00471.x Wick B. Clinical management of binocular vision: Heterophoric, accommodative, and eye movement disorders. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2006.

Methods of Determining the Amount of Prism Prescription in Heterophoria

Abstract

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