Early Findings of Keratoconus, Clinical Management, and the Challenge in Stopping its Progression

ORIGINAL ARTICLE
Mimoza Ismaili

 
For citation: Ismaili M. Early Findings of Keratoconus, Clinical Management, and the Challenge in Stopping its Progression. International Journal of Biomedicine. 2024;14(3):428-434. doi:10.21103/Article14(3)_OA6
 
Originally published September 6, 2024

Abstract: 

Background: Keratoconus (KCN) is considered a bilateral corneal ectatic disorder characterized by cone-like steepening of the cornea and irregular stromal thinning, which can lead to decreased visual acuity. This study aimed to assess the prevalence and risk factors for the KCN development in Kosovo.
Methods and Results: This retrospective study was conducted in the Department of Ophthalmology at the University Clinical Center of Kosovo. The study included 131 respondents, with a total of 262 eyes. Keratometry basis parameters, such as flat keratometry (K1), and steep keratometry (K2), and maximal corneal curvature (Kmax) were determined. Corneal pachymetry was applied to measure the thickness of the cornea. Staging of KCN was done according to the adapted Amsler-Krumeich staging classification system (AK) for anterior data and corneal thickness (CT). Of 262 examined eyes, 240 (91.6%) were KCN eyes, 2(0.8%) were suspect for KCN, and 20(7.6%) were normal. KCN Stage 1 on the AK classification was predominant (P<0.001). We did not find a statistically significant difference between the mean age of patients and the KCN stage (P=0.235). KCN Stage 1 on the AK classification was predominant (52.9%) (P<0.001). We did not find a statistically significant difference between the mean age of patients and the KCN stage (P=0.235). The level of K1 was significantly lower in the non-KCN group (41.4±0.5 D) compared to KCN, and with increasing KCN stage, the K1 value significantly increased, reaching a maximum level in Stage 4 (53.3±4.3 D) (P=0.0000). A similar trend was typical for K2 and Kmax: from 44.7±5.1 D and 44.5±3.1 D, respectively, in the non-KCN group to 55.6±4.9 D and 65.3±8.3 D, respectively, in KCN Stage 4 (P=0.0000). Regarding the CT, the highest values ​​were in the non-KCN group (504.0 ± 27.6 µm), gradually decreasing from KCN Stage 1 to Stage 4 (466.2 ± 36.0 µm vs. 378.6 ± 95.0 µm, P=0.0000).
Conclusion: Screening programs that detect KCN at its earliest grade are the key to enabling early management, halting progression, and preserving the quality of visual acuity.

Keywords: 
keratoconus • keratometry • corneal thickness • corneal topography
References: 
  1. Espandar L, Meyer J. Keratoconus: overview and update on treatment. Middle East Afr J Ophthalmol. 2010 Jan;17(1):15-20. doi: 10.4103/0974-9233.61212. PMID: 20543932; PMCID: PMC2880369.
  2. Najmi H, Mobarki Y, Mania K, Altowairqi B, Basehi M, Mahfouz MS, Elmahdy M. The correlation between keratoconus and eye rubbing: a review. Int J Ophthalmol. 2019 Nov 18;12(11):1775-1781. doi: 10.18240/ijo.2019.11.17. PMID: 31741868; PMCID: PMC6848869.
  3. McMonnies CW. Eye rubbing type and prevalence including contact lens 'removal-relief' rubbing. Clin Exp Optom. 2016 Jul;99(4):366-72. doi: 10.1111/cxo.12343. Epub 2016 Jun 16. PMID: 27306478.
  4. Gordon-Shaag A, Millodot M, Essa M, Garth J, Ghara M, Shneor E. Is consanguinity a risk factor for keratoconus? Optom Vis Sci. 2013 May;90(5):448-54. doi: 10.1097/OPX.0b013e31828da95c. PMID: 23584486.
  5. Gordon-Shaag A, Millodot M, Shneor E. The epidemiology and etiology of keratoconus. Int J Keratoco Ectatic Corneal Dis. 2012;1(1):7–15.
  6. Orucoglu F. Incidence and tomographic evaluation of unilateral keratoconus/Unilateralkeratokonuslarda insidans ve tomografik degerlendirme. Turkish Journal of Ophthalmology. 2013;43(2):83–87.
  7. Gordon-Shaag A, Millodot M, Kaiserman I, Sela T, Barnett Itzhaki G, Zerbib Y, Matityahu E, Shkedi S, Miroshnichenko S, Shneor E. Risk factors for keratoconus in Israel: a case-control study. Ophthalmic Physiol Opt. 2015 Nov;35(6):673-81. doi: 10.1111/opo.12237. Epub 2015 Aug 18. PMID: 26286678.
  8. Ambrósio R Jr, Belin MW. Imaging of the cornea: topography vs tomography. J Refract Surg. 2010 Nov;26(11):847-9. doi: 10.3928/1081597X-20101006-01. PMID: 21053870.
  9. Winkler von Mohrenfels C, Salgado JP, Khoramnia R. Keratektasie nach refraktiver Chirurgie [Keratectasia after refractive surgery]. Klin Monbl Augenheilkd. 2011 Aug;228(8):704-11. German. doi: 10.1055/s-0029-1245754. Epub 2010 Nov 24. PMID: 21108164.
  10. Santodomingo-Rubido J, Carracedo G, Suzaki A, Villa-Collar C, Vincent SJ, Wolffsohn JS. Keratoconus: An updated review. Cont Lens Anterior Eye. 2022 Jun;45(3):101559. doi: 10.1016/j.clae.2021.101559. Epub 2022 Jan 4. PMID: 34991971.
  11. Rabinowitz YS. Keratoconus. Surv Ophthalmol. 1998 Jan-Feb;42(4):297-319. doi: 10.1016/s0039-6257(97)00119-7. PMID: 9493273.
  12. Godefrooij DA, de Wit GA, Uiterwaal CS, Imhof SM, Wisse RP. Age-specific Incidence and Prevalence of Keratoconus: A Nationwide Registration Study. Am J Ophthalmol. 2017 Mar;175:169-172. doi: 10.1016/j.ajo.2016.12.015. Epub 2016 Dec 28. PMID: 28039037.
  13. Ziaei H, Jafarinasab MR, Javadi MA, Karimian F, Poorsalman H, Mahdavi M, Shoja MR, Katibeh M. Epidemiology of keratoconus in an Iranian population. Cornea. 2012 Sep;31(9):1044-7. doi: 10.1097/ICO.0b013e31823f8d3c. PMID: 22710491.
  14. Hashemi H, Heydarian S, Yekta A, Ostadimoghaddam H, Aghamirsalim M, Derakhshan A, Khabazkhoob M. High prevalence and familial aggregation of keratoconus in an Iranian rural population: a population-based study. Ophthalmic Physiol Opt. 2018 Jul;38(4):447-455. doi: 10.1111/opo.12448. Epub 2018 Mar 24. PMID: 29572900.
  15. AMSLER M. [The "forme fruste" of keratoconus]. Wien Klin Wochenschr. 1961 Dec 8;73:842-3. German. PMID: 13861052.
  16. Ertan A, Muftuoglu O. Keratoconus clinical findings according to different age and gender groups. Cornea. 2008 Dec;27(10):1109-13. doi: 10.1097/ICO.0b013e31817f815a. PMID: 19034122.
  17. Lapeyre G, Fournie P, Vernet R, Roseng S, Malecaze F, Bouzigon E, Touboul D. Keratoconus Prevalence in Families: A French Study. Cornea. 2020 Dec;39(12):1473-1479. doi: 10.1097/ICO.0000000000002546. PMID: 32969859.
  18. Laqua H. Hereditäre Erkrankungen beim Keratokonus [Hereditary diseases in keratoconus]. Klin Monbl Augenheilkd. 1971 Nov;159(5):609-18. German. PMID: 4257613.
  19. Hashemi H, Khabazkhoob M, Fotouhi A. Topographic Keratoconus is not Rare in an Iranian population: the Tehran Eye Study. Ophthalmic Epidemiol. 2013 Dec;20(6):385-91. doi: 10.3109/09286586.2013.848458. Epub 2013 Oct 29. PMID: 24168025.
  20. Mohaghegh S, Kangari H, Masoumi SJ, Bamdad S, Rahmani S, Abdi S, Fazil N, Shahbazi S. Prevalence and risk factors of keratoconus (including oxidative stress biomarkers) in a cohort study of Shiraz university of medical science employees in Iran. BMC Ophthalmol. 2023 Apr 28;23(1):188. doi: 10.1186/s12886-023-02934-0. PMID: 37106365; PMCID: PMC10142163.
  21. Rabinowitz YS. The genetics of keratoconus. Ophthalmol Clin North Am. 2003 Dec;16(4):607-20, vii. doi: 10.1016/s0896-1549(03)00099-3. PMID: 14741001.
  22. Balasubramanian SA, Pye DC, Willcox MD. Effects of eye rubbing on the levels of protease, protease activity and cytokines in tears: relevance in keratoconus. Clin Exp Optom. 2013 Mar;96(2):214-8. doi: 10.1111/cxo.12038. Epub 2013 Feb 18. PMID: 23496656.
  23. Shetty R, Sureka S, Kusumgar P, Sethu S, Sainani K. Allergen-specific exposure associated with high immunoglobulin E and eye rubbing predisposes to progression of keratoconus. Indian J Ophthalmol. 2017 May;65(5):399-402. doi: 10.4103/ijo.IJO_217_17. Erratum in: Indian J Ophthalmol. 2017 Jul;65(7):642-643. doi: 10.4103/0301-4738.211110. PMID: 28573997; PMCID: PMC5565884.
  24. Shneor E, Millodot M, Blumberg S, Ortenberg I, Behrman S, Gordon-Shaag A. Characteristics of 244 patients with keratoconus seen in an optometric contact lens practice. Clin Exp Optom. 2013 Mar;96(2):219-24. doi: 10.1111/cxo.12005. Epub 2012 Dec 20. PMID: 23278637.       
  25. McGhee CN, Kim BZ, Wilson PJ. Contemporary Treatment Paradigms in Keratoconus. Cornea. 2015 Oct;34 Suppl 10:S16-23. doi: 10.1097/ICO.0000000000000504. PMID: 26114829.
  26. Naderan M, Shoar S, Rezagholizadeh F, Zolfaghari M, Naderan M. Characteristics and associations of keratoconus patients. Cont Lens Anterior Eye. 2015 Jun;38(3):199-205. doi: 10.1016/j.clae.2015.01.008. Epub 2015 Feb 21. PMID: 25707930.
  27. AlShammari Z, AlShammari R, AlOrf S, AlShammari R, AlShammari W, ALShammari W. Prevalence, clinical features and associated factors of keratoconus patients attending Ophthalmology Department, King Khalid Hospital, Hail City, Saudi Arabia. EC Ophthalmology. 2016;3(5):388–400.
  28. Jafri B, Lichter H, Stulting RD. Asymmetric keratoconus attributed to eye rubbing. Cornea. 2004 Aug;23(6):560-4. doi: 10.1097/01.ico.0000121711.58571.8d. PMID: 15256993.
  29. Hawkes E, Nanavaty MA. Eye rubbing and keratoconus: a literature review. Int J Keratoco Ectatic Corneal Dis. 2014;3(3):118–121.
  30. Owens H, Gamble G. A profile of keratoconus in New Zealand. Cornea. 2003 Mar;22(2):122-5. doi: 10.1097/00003226-200303000-00008. PMID: 12605045.
  31. Millodot M, Shneor E, Albou S, Atlani E, Gordon-Shaag A. Prevalence and associated factors of keratoconus in Jerusalem: a cross-sectional study. Ophthalmic Epidemiol. 2011 Apr;18(2):91-7. doi: 10.3109/09286586.2011.560747. PMID: 21401417.
  32. Baiocchi S, Mazzotta C, Cerretani D, Caporossi T, Caporossi A. Corneal crosslinking: riboflavin concentration in corneal stroma exposed with and without epithelium. J Cataract Refract Surg. 2009 May;35(5):893-9. doi: 10.1016/j.jcrs.2009.01.009. PMID: 19393890.
  33. Mazzotta C, Balestrazzi A, Traversi C, Baiocchi S, Caporossi T, Tommasi C, Caporossi A. Treatment of progressive keratoconus by riboflavin-UVA-induced cross-linking of corneal collagen: ultrastructural analysis by Heidelberg Retinal Tomograph II in vivo confocal microscopy in humans. Cornea. 2007 May;26(4):390-7. doi: 10.1097/ICO.0b013e318030df5a. PMID: 17457184.
  34. Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003 May;135(5):620-7. doi: 10.1016/s0002-9394(02)02220-1. PMID: 12719068.
  35. Mastropasqua L. Collagen cross-linking: when and how? A review of the state of the art of the technique and new perspectives. Eye Vis (Lond). 2015 Nov 29;2:19. doi: 10.1186/s40662-015-0030-6. PMID: 26665102; PMCID: PMC4675057.
  36. Şengör T, Aydın Kurna S. Update on Contact Lens Treatment of Keratoconus. Turk J Ophthalmol. 2020 Aug 26;50(4):234-244. doi: 10.4274/tjo.galenos.2020.70481. PMID: 32854468; PMCID: PMC7469902.
  37. Spoerl E, Mrochen M, Sliney D, Trokel S, Seiler T. Safety of UVA-riboflavin cross-linking of the cornea. Cornea. 2007 May;26(4):385-9. doi: 10.1097/ICO.0b013e3180334f78. PMID: 17457183.
  38. Larkin DFP, Chowdhury K, Burr JM, Raynor M, Edwards M, Tuft SJ, Bunce C, Caverly E, Doré C; KERALINK Trial Study Group. Effect of Corneal Cross-linking versus Standard Care on Keratoconus Progression in Young Patients: The KERALINK Randomized Controlled Trial. Ophthalmology. 2021 Nov;128(11):1516-1526. doi: 10.1016/j.ophtha.2021.04.019. Epub 2021 Apr 21. PMID: 33892046.
  39. Gustafsson I, Vicente A, Bergström A, Stenevi U, Ivarsen A, Hjortdal JØ. Current clinical practice in corneal crosslinking for treatment of progressive keratoconus in four Nordic countries. Acta Ophthalmol. 2023 Feb;101(1):109-116. doi: 10.1111/aos.15213. Epub 2022 Jul 10. PMID: 35811357; PMCID: PMC10084360.
  40. Galvis V, Tello A, Ortiz AI, Escaf LC. Patient selection for corneal collagen cross-linking: an updated review. Clin Ophthalmol. 2017 Apr 7;11:657-668. doi: 10.2147/OPTH.S101386. PMID: 28435217; PMCID: PMC5391157.
  41. Cifariello F, Minicucci M, Di Renzo F, Di Taranto D, Coclite G, Zaccaria S, De Turris S, Costagliola C. Epi-Off versus Epi-On Corneal Collagen Cross-Linking in Keratoconus Patients: A Comparative Study through 2-Year Follow-Up. J Ophthalmol. 2018 Jul 29;2018:4947983. doi: 10.1155/2018/4947983. PMID: 30151277; PMCID: PMC6087595.
  42. Belin MW, Kundu G, Shetty N, Gupta K, Mullick R, Thakur P. ABCD: A new classification for keratoconus. Indian J Ophthalmol. 2020 Dec;68(12):2831-2834. doi: 10.4103/ijo.IJO_2078_20. PMID: 33229658; PMCID: PMC7856970.
  43. Hashemi H, Beiranvand A, Yekta A, Maleki A, Yazdani N, Khabazkhoob M. Pentacam top indices for diagnosing subclinical and definite keratoconus. J Curr Ophthalmol. 2016 Mar 29;28(1):21-6. doi: 10.1016/j.joco.2016.01.009. PMID: 27239598; PMCID: PMC4881219.
  44. Ghassembaglou N, Djalilian AR. Keratoconus; a True Corneal Disease. J Ophthalmic Vis Res. 2016 Jan-Mar;11(1):1-2. doi: 10.4103/2008-322X.180701. PMID: 27195077; PMCID: PMC4860973.
  45. Rubinfeld RS, Littner R, Trattler WB, Rocha K, Talamo J, Lindstrom RL. Pentacam HR criteria for curvature change in keratoconus and postoperative LASIK ectasia. J Refract Surg. 2013 Oct;29(10):666. doi: 10.3928/1081597X-20130919-02. PMID: 24094309.
  46. Mahmoud AM, Nuñez MX, Blanco C, Koch DD, Wang L, Weikert MP, Frueh BE, Tappeiner C, Twa MD, Roberts CJ. Expanding the cone location and magnitude index to include corneal thickness and posterior surface information for the detection of keratoconus. Am J Ophthalmol. 2013 Dec;156(6):1102-11. doi: 10.1016/j.ajo.2013.07.018. Epub 2013 Sep 25. PMID: 24075426.
  47. Guber I, McAlinden C, Majo F, Bergin C. Identifying more reliable parameters for the detection of change during the follow-up of mild to moderate keratoconus patients. Eye Vis (Lond). 2017 Oct 25;4:24. doi: 10.1186/s40662-017-0089-3. PMID: 29124079; PMCID: PMC5655968.
  48. Choi JA, Kim MS. Progression of keratoconus by longitudinal assessment with corneal topography. Invest Ophthalmol Vis Sci. 2012 Feb 23;53(2):927-35. doi: 10.1167/iovs.11-8118. PMID: 22247476.
  49. Du XL, Chen M, Xie LX. Correlation of basic indicators with stages of keratoconus assessed by Pentacam tomography. Int J Ophthalmol. 2015 Dec 18;8(6):1136-40. doi: 10.3980/j.issn.2222-3959.2015.06.10. PMID: 26682161; PMCID: PMC4651877.
  50. Atalay E, Özalp O, Yıldırım N. Advances in the diagnosis and treatment of keratoconus. Ther Adv Ophthalmol. 2021 Jun 24;13:25158414211012796. doi: 10.1177/25158414211012796. PMID: 34263132; PMCID: PMC8246497.
  51. Koch DD, Ali SF, Weikert MP, Shirayama M, Jenkins R, Wang L. Contribution of posterior corneal astigmatism to total corneal astigmatism. J Cataract Refract Surg. 2012 Dec;38(12):2080-7. doi: 10.1016/j.jcrs.2012.08.036. Epub 2012 Oct 12. PMID: 23069271.
  52. Fam HB, Lim KL. Corneal elevation indices in normal and keratoconic eyes. J Cataract Refract Surg. 2006 Aug;32(8):1281-7. doi: 10.1016/j.jcrs.2006.02.060. PMID: 16863962.

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Received June 17, 2024.
Accepted August 26, 2024.
©2024 International Medical Research and Development Corporation.