:: Volume 8, Issue 2 (5-2019) ::
Int J Med Invest 2019, 8(2): 12-22 Back to browse issues page
Prevalence of Keratoconus in Patients with Astigmatism more than Two Diopters: A Cross-Sectional Study
Abas Nazar Shakir *, Eman Hussein Alwan
M.B.Ch.B, Erbil Teaching Hospital, General Directorate of Erbil Health, Ministry of Health, the Kurdistan Region, Iraq.
Abstract:   (1571 Views)
Background and aim: Keratoconus is defined as a non-inflammatory disorder which is prevalent among younger generations and leads to ocular morbidity and decreased quality of life. The present study was aimed at investigating the prevalence of keratoconus among patients with astigmatism of over 2 diopters and the association between its prevalence and some ocular parameters.
Methods: In a cross-sectional study, 50 patients (100 eyes) with astigmatism >2D who referred to the outpatient clinic of Ophthalmology Department in Hawler and Rizgary Teaching Hospital in Erbil in 2017-2018 were recruited. All of the patients underwent a complete ophthalmic examination including refraction, visual acuity measurement, slit lamp biomicroscopy, and corneal topography with Galilei. The collected data were analyzed through thickness and elevation maps of Galilei and Statistical Package for the Social Sciences version 20.0.
Results: The mean age of the patients was 25.27 years. The mean magnitude of astigmatism was found to be 4.015±1.83051D. Of the 100 studied eyes, 21% were found to have keratoconus. According to the results of corneal biomicroscopy, thinning of stroma was observed in 21 eye, followed by Vogt’s striae and Fleischer ring in 8 and 6 eyes, respectively. The most frequent corneal patterns were symmetric bowtie (49%), asymmetric bowtie inferior steeping (15%), and asymmetric bowtie with skewed steepest radial axis (12%). No significant relationship was found between age and keratoconus occurrence. Also, keratoconus development was not significantly associated with right/left eye. However, corneal topography patterns and corneal biomicroscopy findings were significantly correlated with keratoconus occurrence.
Conclusion: Keratoconus is relatively high among patients aged 15-40 years with astigmatism >2D, which can reliably be predicted through thinning of stroma and symmetric bowtie pattern.
Keywords: keratoconus, subclinical keratoconus, astigmatism, corneal topography, corneal tomography
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Type of Study: Research | Subject: General
1. 1. Krachmer JH, Feder RS, Belin MW. Keratoconus and related noninflammatory corneal thinning disorders. Surv Ophthalmol. 1984;28:293–322. 2. Rabinowitz YS. Keratoconus. Surv Ophthalmol. 1998;42:297–319. 3. Gatinel D, Saad A. The challenges of the detection of subclinical keratoconus at its earliest stage. Int J Keratoco Ectatic Corneal Dis. 2012; 1(1): 36-43. 4. Galvis V, Sherwin T, Tello A, Merayo J, Barrera R, Acera A. Keratoconus: an inflammatory disorder?. Eye (Lond). 2015;29(7):843–859. doi:10.1038/eye.2015.63 5. Georgiou T, Funnell CL, Cassels-Brown A, O'Conor R. Influence of ethnic origin on the incidence of keratoconus and associated atopic disease in Asians and white patients. Eye (lond) 2004; 18: 379–383. 6. Bechara SJ, Waring GO, Insler MS. Keratoconus in two pairs of identical twins.Cornea.1996; 15:90–3. 7. Qasim KF and Shahad A. Prevalence of Refractive Errors in Patients with Keratoconus among Sample of Iraqi Population. J Ophthalmol 2017, 2(4): 000134. 8. Gorskova E. N., Sevost’ianov E. N. Epidemiology of keratoconus in the Urals. Vestnik Oftalmologii. 1998;114:38–40. in Russian. 9. Kennedy R. H., Bourne W. M., Dyer J. A. A 48-year clinical and epidemiologic study of keratoconus. American Journal of Ophthalmology. 1986;101:267–273. doi: 10.1016/0002-9394(86)90817-2. 10. Jonas J. B., Nangia V., Matin A., et al. Prevalence and associations of keratoconus in rural Maharashtra in central India: the central India eye and medical study. American Journal of Ophthalmology. 2009;148:760–765. doi: 10.1016/j.ajo.2009.06.024. 11. Hashemi H, Khabazkhoob M, Yazdani N, Ostadimoghaddam H, Norouzirad R, Amanzadeh K et al. The prevalence of keratoconus in a young population in Mashhad, Iran. Ophthalmic Physiol Opt 2014; 34: 519–527. 12. Galvis V, Tello A, Jaramillo JA, Gutierrez AJ, Rodriguez L, Quintero MP. Prevalence of keratoconus patients who consulted with a desire refractive surgery in ophthalmology center reference Bucaramanga, Colombia. Rev Soc Colomb Oftal 2011; 44: 129–134. 13. Dutta N. K., Dutta L. C. Modern Ophthalmology. 3rd. New Delhi, India: Jaypee Brothers; 2005. Applied and functional anatomy of the cornea; p. p. 131. 14. Gordon-Shaag A., Millodot A., Shneor E., Liu Y. The genetic and environmental factors for keratoconus. BioMed Research International. 2015;2015:p. 19. doi: 10.1155/2015/795738.795738 15. M. Millodot, E. Shneor, S. Albou, E. Atlani, and A. Gordon-Shaag, “Prevalence and associated factors of keratoconus in jerusalem: a cross-sectional study,” Ophthalmic Epidemiology, vol. 18, no. 2, pp. 91–97, 2011. 16. Vazirani J, Basu S. Keratoconus: current perspectives. Clin Ophthalmol. 2013;7:2019–2030. doi:10.2147/OPTH.S50119 17. Kanski J, Bowling B, Nischal K and Pearson A.Clinical ophthalmology. 7th ed. Edinburgh: Elsevier/Saunders; 2011 p.210-212. 18. McMahon TT, Edrington TB, Szczotka-Flynn L, Olafsson HE, Davis LJ, Schechtman KB. Longitudinal changes in corneal curvature in keratoconus. Cornea. 2006;25:296–305. 19. Li X, Rabinowitz YS, Rasheed K, Yang H. Longitudinal study of the normal eyes in unilateral keratoconus subjects. Ophthalmology 2004;111:440-446 20. Belin MW, Villavicencio OF, Ambrosio R Jr. Tomographic parameters for the detection of keratoconus: suggestions for screening and treatment parameters. Eye Contact Lens. 2014; 40:326–330. 21. Feizi S, Yaseri M, Kheiri B. Predictive Ability of Galilei to Distinguish Subclinical Keratoconus and Keratoconus from Normal Corneas. J Ophthalmic Vis Res. 2016;11(1):8–16. doi:10.4103/2008-322X.180707 22. H. Hashemi, S. Heydarian, A. Yekta et al., “High prevalence and familial aggregation of keratoconus in an Iranian rural population: a population-based study,” Ophthalmic and Physiological Optics, vol. 38, pp. 447–455, 2018. 23. Kymes SM, Walline JJ, Zadnik K, Sterling J, Gordon MO. Changes in the quality-of-life of people with keratoconus. Am J Ophthalmol. 2008;145 (4:611–617. 24. Davis LJ, Schechtman KB, Wilson BS, Rosenstiel CE, Riley CH, Libassi DP, et al. Longitudinal changes in visual acuity in keratoconus. Invest Ophthalmol Vis Sci. 2006;47 (2:489–500. 25. Serdarogullari H, Tetikoglu M, Karahan H, Altin F, Elcioglu M. Prevalence of keratoconus and subclinical keratoconus in subjects with astigmatism using pentacam derived parameters. J Ophthalmic Vis Res. 2013;8(3):213–219. 26. Shehadeh MM, Diakonis VF, Jalil SA, Younis R, Qadoumi J, Al-Labadi L. Prevalence of Keratoconus Among a Palestinian Tertiary Student Population. Open Ophthalmol J. 2015;9:172–176. Published 2015 Dec 31. doi:10.2174/1874364101509010172 27. ala El Rami, Elias Chelala, Ali Dirani, et al., “An Update on the Safety and Efficacy of Corneal Collagen Cross-Linking in Pediatric Keratoconus,” BioMed Research International, vol. 2015, Article ID 257927, 7 pages, 2015. 28. Shajari M, Friderich S, Pour Sadeghian M, Schmack I, Kohnen T. Characteristics of Corneal Astigmatism of Anterior and Posterior Surface in a Normal Control Group and Patients With Keratoconus. Cornea. 2017;36:457–462. 29. Feizi S, Delfazayebaher S, Javadi MA, Karimian F, Ownagh V, Sadeghpour F. Mean Posterior Corneal Power and Astigmatism in Normal Versus Keratoconic Eyes. J Ophthalmic Vis Res. 2018;13(2):93–100. doi:10.4103/jovr.jovr_19_17 30. Reinstein DZ, Gobbe M, Archer TJ, Silverman RH, Coleman DJ. Epithelial, stromal, and total corneal thickness in keratoconus: three-dimensional display with artemis very-high frequency digital ultrasound. J Refract Surg. 2010;26(4):259–271. doi:10.3928/1081597X-20100218-01 31. Zhou W, Stojanovic A. Comparison of corneal epithelial and stromal thickness distributions between eyes with keratoconus and healthy eyes with corneal astigmatism ≥ 2.0 D. PLoS One. 2014;9(1):e85994. Published 2014 Jan 28. doi:10.1371/journal.pone.0085994 32. Grieve K, Ghoubay D, Georgeon C, Latour G, Nahas A, Plamann K, Crotti C, Bocheux R, Borderie M, Nguyen TM, Andreiuolo F, Schanne-Klein MC, Borderie V. Stromal striae: a new insight into corneal physiology and mechanics. Sci Rep. 2017 Oct 19;7(1):13584. 33. Shi Y. Strategies for improving the early diagnosis of keratoconus. Clin Optom (Auckl). 2016;8:13–21. Published 2016 Feb 24. doi:10.2147/OPTO.S63486 34. Munsamy AJ, Moodley VR, Naidoo P, Mangwarara TR, Abdullah R, Govender D, et al. A frequency analysis of cone characteristics for the different stages of keratoconus. Afr Vision Eye Health. 2015;74(1) 35. Cavas-Martínez F, De la Cruz Sánchez E, Nieto Martínez J, Fernández Cañavate FJ, Fernández-Pacheco DG. Corneal topography in keratoconus: state of the art. Eye Vis (Lond). 2016;3:5. Published 2016 Feb 22. doi:10.1186/s40662-016-0036-8 36. Matalia H, Swarup R. Imaging modalities in keratoconus. Indian J Ophthalmol. 2013;61(8):394–400. doi:10.4103/0301-4738.116058 37. Patrao LF, Canedo AL, Azevedo JL, Correa R, Ambrosio R, Jr. Differentiation of mild keratoconus from corneal warpage according to topographic inferior steepening based on corneal tomography data. Arq Bras Oftalmol. 2016;79:264-7. 38. M. Abdu, K.H. Binnawi, A.E.M. Elmadina, R. Hassan Clinical profile of keratoconus patients in Sudan Sudan J Ophthalmol, 8 (1) (2016), pp. 20-25 39. Panahi-Bazaz MR, Sharifipour F, Moghaddasi A. Bilateral Keratoconus and Corneal Hydrops Associated with Eye Rubbing in a 7-year-old Girl. J Ophthalmic Vis Res. 2014;9(1):101–105. 40. Dienes L, Kranitz K, Juh asz E, Gyenes A, Tak acs A, Mil altz K, Nagy ZZ, Kovacs I. Evaluation of intereye corneal asymmetry in patients with keratoconus. A Scheimpflug imaging study. PLoS One 2014; 9:e108882. 41. Güngör IU, Beden U, Sönmez B. Bilateral horizontal Vogt's striae in keratoconus. Clin Ophthalmol. 2008;2(3):653–655. 42. Song P, Wang S, Zhang P, et al. The Superficial Stromal Scar Formation Mechanism in Keratoconus: A Study Using Laser Scanning In Vivo Confocal Microscopy. Biomed Res Int. 2016;2016:7092938. doi:10.1155/2016/7092938 43. Khaled ML, Helwa I, Drewry M, Seremwe M, Estes A, Liu Y. Molecular and Histopathological Changes Associated with Keratoconus. Biomed Res Int. 2017;2017:7803029. doi:10.1155/2017/7803029

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Volume 8, Issue 2 (5-2019) Back to browse issues page