Prediction of the Refractive Error Based on Snellen chart and OPD-scan III Visual Acuity

Document Type : Original Article

Authors

1 Department of Optometry, Faculty of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran

2 Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran

3 Epidemiological Research Center for Eye Diseases, Noor Ophthalmology Hospital, Tehran, Iran

Abstract

Purpose:
To predict the spherical refractive error and astigmatism based on Snellen chart and OPD-scan III visual acuity in visually normal individuals.
Methods:
This study was performed on seventy five participants with an age range of 18 to 35 years. Visual acuity and refractive errors were evaluated using both subjective Snellen chart and OPD-scan III devices. The Pearson correlation test was used to evaluate the correlation between visual acuity and refractive errors. Moreover, to predict refraction based on the visual acuity, linear regression was performed.
Results:
The results of the Pearson correlation test showed a significant negative correlation between visual acuity and refractive error in the myopic group (p<0.0001, r=-0.859 for subjective visual acuity, r=-0.788 for objective visual acuity). In addition, there was a significant positive correlation in the hyperopic group (p<0.0001, r= 0.882 for objective visual acuity). However, there was no significant correlation between subjective visual acuity and spherical refractive errors. Also, no significant correlation was found between astigmatism and visual acuity of the eye (p>0.05).
Conclusion:
Considering the high correlation between visual acuity and spherical refractive errors in myopic groups, refraction may be estimated based on the visual acuity of the eye. While in hyperopic group, there is no possibility to predict the refraction based on subjective visual acuity. Considering the poor correlation between visual acuity and astigmatism, astigmatism cannot be estimated based on the visual acuity of the eye.

Keywords


  1.  Chen A-H, Norazman FNN, Buari NH. Comparison of visual acuity estimates using three different letter charts under two ambient room illuminations. Indian journal of ophthalmology. 2012; 60(2): 101-104.
  2. Raasch TW, Bailey IL, Bullimore MA. Repeatability of visual acuity measurement. Optometry & Vision Science 1998; 75(5): 342-348.
  3. Grosvenor T, Grosvenor TP. Primary care optometry: Elsevier Health Sciences; 2007: 8-12.
  4. Lim L, Frost N, Powell R, Hewson P. Comparison of the ETDRS logMAR,‘compact reduced logMar’and Snellen charts in routine clinical practice. Eye 2010; 24(4): 673-677.
  5. Kaiser PK. Prospective evaluation of visual acuity assessment: a comparison of snellen versus ETDRS charts in clinical practice (An AOS Thesis). Trans Am Ophthalmol Soc 2009; 107: 311-324.
  6. Falkenstein IA, Cochran DE, Azen SP, Dustin L, et al. Comparison of Visual Acuity in Macular Degeneration Patients Measured with Snellen and Early Treatment Diabetic Retinopathy Study Charts. Ophthalmology 2008; 115(2): 319-323.
  7. Amos JF, Bartlett JD. Clinical procedures in optometry: Lippincott Williams & Wilkins; 1991.
  8. Bennett JR, Stalboerger GM, Hodge DO, Schornack MM. Comparison of refractive assessment by wavefront aberrometry, autorefraction, and subjective refraction. Journal of optometry 2015; 8(2): 109-115.
  9. Choong Y-F, Chen A-H, Goh P-P. A comparison of autorefraction and subjective refraction with and without cycloplegia in primary school children. American journal of ophthalmology 2006; 142(1): 68-74.
  10. Jorge J, Queiros A, Almeida JB, Parafita MA. Retinoscopy/autorefraction: which is the best starting point for a noncycloplegic refraction? Optometry & Vision Science 2005; 82(1): 64-68.
  11. Kinge B, Midelfart A, Jacobsen G. Clinical evaluation of the Allergan Humphrey 500 autorefractor and the Nidek AR-1000 autorefractor. British journal of ophthalmology 1996; 80(1): 35-39.
  12. Pesudovs K, Weisinger HS. A comparison of autorefractor performance. Optometry & Vision Science 2004; 81(7): 554-558.
  13. Lebow KA, Campbell CE. A comparison of a traditional and wavefront autorefraction. Optometry & Vision Science 2014; 91(10): 1191-1198.
  14. Alio JL, Krueger RR, Wilson SE. Wavefront Analysis, Aberrometers & Corneal Topography: Highlights of Ophthalmology International City of Knowledge; 2003. 321.
  15. McGinnigle S, Naroo SA, Eperjesi F. Evaluation of the auto‐refraction function of the Nidek OPD‐Scan III. Clinical and experimental optometry 2014; 97(2): 160-163.
  16. Visser N, Berendschot TT, Verbakel F, Tan AN, et al. Evaluation of the comparability and repeatability of four wavefront aberrometers. Investigative ophthalmology & visual science 2011; 52(3): 1302-1311.
  17. eye and health care Nidek Co; LTD.Refractive Power/Corneal Analyser OPD-scanIII. japan; 2011: 194-196.
  18. Applegate RA, Marsack JD, Ramos R, Sarver EJ. Interaction between aberrations to improve or reduce visual performance. Journal of Cataract & Refractive Surgery 2003; 29(8): 1487-1495.
  19. Bradley A, Thomas T, Kalaher M, Hoerres M. Effects of spherical and astigmatic defocus on acuity and contrast sensitivity: a comparison of three clinical charts. Optometry & Vision Science. 1991; 68(6): 418-426.
  20. Elliott DB. Clinical procedures in primary eye care.bradford.UK: Elsevier Health Sciences; 2013.74-75.
  21. Yan, xin, Su Xiaogang.linear regression analysis: theory and comuting. world scientific; 2009: 9-10.
  22. Crawford J, Shagass C, Pashby T. Relationship between visual acuity and refractive error in myopia. American Journal of Ophthalmology 1945; 28(11): 1220-5.
  23. Peters HB. The relationship between refractive error and visual acuity at three age levels.Optometry & Vision Science 1961; 38(4): 194-198.
  24. Prince JH, Fry GA. The effect of errors of refraction on visual acuity. Optometry & Vision Science 1956; 33(7): 353-373.
  25. Ogle KN. On the problem of an international nomenclature for designating visual acuity. American journal of ophthalmology 1953; 36(7): 909-921.
  26. Smith G. Relation between spherical refractive error and visual acuity. Optometry and Vision Science 1991; 68(8): 591-598.
  27. Raasch TW. Spherocylindrical refractive errors and visual acuity. Optometry & Vision Science 1995; 72(4): 272-275.
  28. Moore, B. D., Augsburger, A. R., Ciner, E. B., Cockrell, D. A., & Fern, K.Optometric clinical practice guideline: care of the patient with hyperopia. American Optometric Association; 1997: 1-29.