Abstract

Introduction: Visual Evoked Potentials are summated electrical signals generated by occipital regions of cortex in response to visual stimuli and recorded from human scalp. Visual evoked potential measures the conduction time of neuronal activity from retina to occipital cortex, the measure of integrity and function of visual pathway. The amplitude and latency of visual evoked potential are affected by variety of physiological factors like refractive errors, age, gender, eye movement and also the techniques like check size, color, distance to pattern etc. To find out the effect of myopia on visual evoked potential, this study was conducted on males and females.

Method: 50 controls [25 males, 25 females] and 50 myopic [25males, 25 females] aged between 18-30 years with refractive error in range of -0.5D to -5.00 D were participated with cylindrical component less than -1.00 D with no significant difference in spherical equivalent between the eyes. VEP was measured using full field pattern reversal checkerboard pattern as stimuli and refractive error as measured both objectively and subjectively.

Results: Statistical analysis showed significant prolongation of P100 latency in myopic subjects along with significant reduction in P100 amplitude. When compared according to gender P100 latency significantly increased and the amplitude decrease was also found significant. When Spherical equivalent was co related with VEP latency and amplitude in the whole group, VEP latency showed negative correlation and weak positive correlation for VEP amplitude which was insignificant. When co-relating in males, we found negative correlation for latency and insignificant amplitude whereas in females, latency showed negative correlation with significant amplitude.

Conclusion: As significant changes in VEP was seen in case of myopia in both genders, refractive errors should also be kept in mind while performing VEP for optic pathway evaluations in order to minimize false positive results.

Keywords: VEP - Pattern Reversal; Amplitude; Latency; Myopia; BMI

References

1. Carter JL. “Visual Evoked Potential”. In: Clinical Neurophysiology. ed. Daube JR (2) and Rubin DI. 3rd ed.311-22. Oxford University Press (2009).
2. Kothari Ruchi., et al. “Influence of Refractory error on the Pattern Reversal VEPs of Myopes and Hypermetropes”. International Journal of Physiology 1 (2013): 57-61.
3. Collins DW., et al. “Effect of Refractive error on visual evoked response”. British Medical Journal 1 (1979): 231-232.
4. Lee SM., et al. “The change of VEPs in patient with myopia in correction of refraction”. Korean Academy of Rehabilitation Medicine 26 (2002): 734-738.
5. Celesia GG. “Evoked potential techniques in the evaluation of visual function”. Journal of Clinical Neurophysiology1 (1984): 55-76.
6. Stockard JJ., et al. “Visually Evoked Potential to Electronic Pattern reversal: Latency variations with gender, age and technical factors”. American Journal of Engineering and Technology Management 19 (1979): 171.
7. Sangeeta Gupta and Gaurav Gupta VK Deshpande. “Visual Evoked Potentials: Impact of age, gender, head size and BMI”. 7.1 (2016) :022-026.
8. Michael J AMINOFF. Electro diagnosis in clinical Neurology 5th ed. (2005): 45.
9. J Varnon Odom., et al. “ISCEV Standard for Clinical Visual Evoked Potential”. Documenta Ophthalmologica 120 (2010): 111-119.
10. Clinical Refraction, Irvin m. Borish’s (2nd edition).
11. Sashank Prasad and Steven L Galatte. “Anatomy and Physiology of Afferent Visual System”. Handbook of Clinical Neurology 102 (3rd Series).
12. Anatomy and Physiology of Eye AK Khurana (2nd edition , Visual Pathway and Physiology of Vision).
13. Thomas Wright, Signal Identification for Visual Electrophysiology.
14. Facts about refractive error (NEI) (2010).
15. Vinodha R and ShanugapriyaC. “Effect of Refractive Error on VEP in Myopic Boys and Girls” (2005).
16. “Visual Evoked Potential (VEP): Basic Concepts And Clinical applications”. Journal of the American Optometric Association 34 (1979): 154-170.
17. Ludlam WN and Maeyrs RR. “The use of Visual Evoked Responses in Objective Refraction”. Transactions of the New York Academy of Sciences 34 (1973): 154-170.
18. La Marche JA., et al. “Amplitude of Visually Evoked Potentias to Patterned Stimuli; age and sex comparison”. Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section 65 (1986): 81-85.
19. Emmerson –Hanover R., et al. “Pattern reversal evoked potential: Gender differences and age related changes in amplitude and latency”. Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section 92 (1994): 93-101.
20. Fenwick PB., et al. “The visual evoked response to pattern reversal in normal 6-11 year old children”. Electroencephalography and Clinical Neurophysiology 51 (1981): 49-56.
21. Gregori B., et al. “Vep latency: sex and head size”. Clinical Neurophysiology 117 (2006): 1154-1157.
22. Kaneda Y., et al. “Sex differences in VEP and electroencephalogram of healthy adults”. Tokushima Journal of Experimental Medicine 43 (1996): 143-157.
23. Celesia GG., et al. “Simultaneous recording of pattern electroretinography and visual evoked potentials”. Electroencephalography and Clinical Neurophysiology.
24. The impact of myopia and high myopia: report of the joint world health organization- Brien Holden Vision Institute Global Scientific Meeting on Myopia, University of New South Wales, Sydney, Australia, (2015).
25. https://www.cdc.gov>bmiforpractitioners
26. Anand A., et al. “Short duration transient evoked potential for objective measurement of refractive errors”. Documenta Ophthalmologica 123 (2011): 141-147.
27. Ruby Sharma., et al. “Visual evoked potentials: n normative values and gender differences”. Journal of Clinical and Diagnostic Research 7 (2015): CC12-CC1512.

Citation

Citation: Chanda Kumari Gupta., et al. “Effect of Refractive Error on Visual Evoked Potential in Myopic Males and Females".Acta Scientific Ophthalmology 4.1 (2021): 22-26.

Copyright

Copyright: © 2021 Chanda Kumari Gupta., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.