Peripapillary Retinal Nerve Fiber Layer Thickness by Optical Coherence Tomography in Patients with Unilateral Amblyopia
Iraqi Postgraduate Medical Journal,
2021, Volume 20, Issue 1, Pages 91-98
Amblyopia is a common cause of unilateral visual defect, affecting patients with history of strabismus, refractive errors, and those who had visual deprivation in the critical period of visual development. Amblyopia may have an effect on various levels of the visual pathway. Cells atrophy in the lateral geniculate nucleus that receives information from the affected eye, and a shift in the dominance pattern in the visual cortex have been reported. Retinal involvement in amblyopia is controversial.
SUBJECTS AND METHODS:
This is a cross sectional study carried out in Al-Shaheed Ghazi al-Hareery Teaching Hospital in Medical City at Baghdad, Iraq .Forty-two patients with unilateral amblyopia were selected, 23 males and 19 females with age range of 12-40(mean age of 25.33 years) all of these patients had one amblyopic eye and the other eye normal. OCT scan was done for both eyes of each patient and the RNFLT measured after complete ophthalmological examination ( VA, refraction, slit lamp, and funduscopic examination
It has been noticed that the mean of NFLT in normal eyes was higher than that of amblyopic eyes (108.88 versus 105.05) but this difference was statistically not significant (P=0.074).
OCT is a sensitive way to estimate RNFLT, we concluded that there is no statistically significant difference in NFLT between the amblyopic, compared to the normal eyes. Also NFLT seems not affected by: type of amblyopia, age of patients and also the severity of amblyopia as all these factors didn’t reach statistical significant.
- Valentin Dragoi. Visual processing and cortical pathway (second editioin) 1997:24-33.
- Lee Ann Remington. Clinical anatomy and physiology of the visual system (third edition) 2012: 233-52.
- Moraes D, Gustavo C. Anatomy of visual pathways. Journal of glaucoma 2013 :S2-S7.
- Drs. Paul L. Kaufman, Albert Alm, Leonard A Levin, Siv F. E. Nilsson, James Ver Hoeve, and Samuel Wu. Adler’s physiology of the eye (11th edition) 2011; chapter 40 : 745-46.
- National Eye Institute [Online]. 2013 [Accessed 2017.
- 6. Available from: URL: https://nei.nih.gov/.
- health dictionary [online]. 2002 [accessed 2009 july 12].
- Available from: URL: http://health-acne-info.blogspot.com/2009/07/definition-of-amblyopia-nocturnal.html
- Prevalence of Amblyopia and Strabismus - Ophthalmology [Online]. [Accessed 2017 Sep3]. Available from: URL:http://www.aaojournal.org/article/S0161-6420(10)00700-1/fulltext.
10. Vision Screening for Amblyopia. American Academy of Ophthalmology [Online]. 2015 OCT 21. [Accessed 2017 Oct 21].Available from: URL: https://www.aao.org/disease-review/vision-screening-amblyopia.
11. Lempert P. Retinal area and optic disc rim area in amblyopic, fellow, and normal hyperopic eyes: a hypothesis for decreased acuity in amblyopia. Ophthalmology 2008 ;115:2259-61.
12. Referat ambliopia [Online]. [Accessed 2017 Oct 10].Available from: URL: https://emedicine.medscape.com/article/1214603-overview#a6.
14. Hubel DH. Wiesel TN. Receptive fields of cells in striate cortex of very young inexperienced kittens. J Neuropbysiol. 1993 Nov 1 26:994-1002.
15. Crawford ML, von Noorden GK. Optically induced concomitant strabismus in monkeys. Invest Ophthalmol Vis Sci. 2000; 19:1105-9.
16. Arden GB, Wooding SL. Pattern ERG in amblyopia . 1995 ; 26:88-96.
18. Ikeda H, Tremain KE. Amblyopia occurs in retinal ganglion cells in cats reared with convergent squint without alternating fixation. Exp Brain Res. 1999 ;35:559-82.
19. Cleland BG, Mitchell DE, Crewther SG, Crewther DP. Visual resolution of retinal ganglion cells in monocularly-deprivated cats. Brain Res 2005 ; 192:261-66.
20. Cleland BG, Crewther DP, Crewther SG, Mitchell DE. Normality of spatial resolution of retinal ganglion cells in cats with strabismic amblyopia. J Physiol. 1992 ;326:235-49.
21. Lempert P, Porter L. Dysversion of the optic disc and axial length measurements in a presumed amblyopic population. J AAPOS. 1998 ;4:207-13.
22. Lempert P. Optic nerve hypoplasia and small eyes in presumed amblyopia. J AAPOS. 2000 4:258-66.
23. Lempert P. Retinal area and optic disc rim area in amblyopic, fellow, and normal hyperopic eyes: a hypothesis for decreased acuity in amblyopia. Ophthalmology. 2008 ;115:2259-61.
24. American Academy of Ophthalmology. Basic and Clinical Science Coarse; section 6 Pediatric Ophthalmology & Strabismus 2009- 2010:67-75.
25. Cathy Williams. Amblyopia. BMJ Clinical evidence. 2009 ; 16: 0709.
26. Bagga H, Greenfield DS, Feuer W, Knighton RW. Scanning laser polarimetry with variable corneal compensation and optical coherence tomography in normal and glaucomatous eyes. Am J Ophthalmol. 2003 ;135:521–529.
27. Gürses-Ozden R, Liebmann JM, Schuffner D, Buxton DF, Soloway BD, Ritch R. Retinal nerve fiber layer thickness remains unchanged following laser-assisted in situ keratomileusis. Am J Ophthalmol. 2001 Oct 132:512–516.
29. Joshua Yuen, Brad Johnson. OCT scanning. Northern eye surgeons. [ Accessed 2013 Oct 4] available from URL: http://www.northerneyesurgeons.com.au/
30. Donald L. Budenz, Symmetry between the Right and Left Eyes of the Normal Retinal Nerve Fiber Layer Measured with Optical Coherence Tomography. Trans American Ophthalmol Soc. 2008; 106: 252–75.
31. Hess RF, Thompson B, Gole G, Mullen KT. Deficient responses from the lateral geniculate nucleus in humans with amblyopia. Eur J Neurosci. 2009;29:1064–70.
32. Pascual M, Huang J, Maguire MG, et al; Vision in Preschoolers (VIP) Study Group. Risk factors for amblyopia in the vision in preschooler’s study. Ophthalmology. 2014;121:622–29.e1.
33. Webber, A. L. and Wood, J. Amblyopia: prevalence, natural history, functional effects and treatment, Clin. Exper. Optomet. 2005; 88: 365–75.
34. Yoon SW, Park WH, Baek SH, et al. Thicknesses of macular retinal layer and peripapillary retinal nerve fiber layer in patients with hyperopic anisometropic amblyopia. Korean J Ophthalmol. 2005;19: 62-67.
35. Atakan M, Çulfa S, Çalli U, Penbe AD, Atakan TG, Özertürk Y. Evaluation of Retinal Nerve Fiber Layer and Macular Thickness in Amblyopia. J Clin Exp Ophthalmol. 2015;6:2.
36. Kasem MA, Badawi AE. Changes in macular parameters in different types of amblyopia: optical coherence tomography study. Clinical ophthalmology (Auckland, NZ). 2017; 11:1407.
37. Kee SY, Lee SY, Lee YC. Thicknesses of the fovea and retinal nerve fiber layer in amblyopic and normal eyes in children. Korean Journal of Ophthalmology. 2006 ;20:177-81.
38. Repka MX, Kraker RT, Tamkins SM, Suh DW, Sala NA, Beck RW. Retinal nerve fiber layer thickness in amblyopic eyes. American journal of ophthalmology. 2009;148:143-7.
39. Huynh SC, Samarawickrama C, Wang XY, Rochtchina E, Wong TY, Gole GA, et al. Macular and nerve fiber layer thickness in amblyopia: The Sydney Childhood Eye Study. Ophthalmology. 2009;116:16.
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