Impact of Hypothyroidism on Tomography and Biomechanics in Keratoconus – Cross-Sectional and Longitudinal Assessment within the Homburg Keratoconus Center at the Time of Inclusion and after 1 Year

Abstract

Background and Purpose The etiology of keratoconus (KC) is probably multifactorial but remains essentially unknown. Previous scientific observations have suggested that hypothyroidism might play a role in the development and progression of KC. The purpose of this study was to analyze the tomographic and biomechanical parameters in KC patients with or without hypothyroidism.

Methods Twenty-eight patients with KC and hypothyroidism (HT group) and fifty-six KC patients without thyroid dysfunction (WHT group) with matching gender and age were analyzed. Mean age was 40.3 years (range 14 – 57) in the HT group and 40.3 years (range 14 – 57) in the WHT group. Routine ophthalmic examinations consisted of corneal tomography and biomechanical parameters. We extracted the following KC parameters from the Pentacam (Pentacam HR, Oculus, Wetzlar, Germany): Keratoconus Index (KI), maximum keratometry (K_max), astigmatism, and thinnest pachymetry (TP). From the ocular response analyzer (ORA, Reichert Ophthalmic Instruments, Depew, NY, USA), we extracted corneal hysteresis (CH), corneal resistance factor (CRF), and KC match index (KMI).

Results The comparison of the tomographic and biomechanical values from cross-sectional and longitudinal analyses showed no significant differences between the HT and WHT groups.

Conclusion The severity of KC based on tomographical and biomechanical parameters does not seem to depend on the presence of hypothyroidism.

Zusammenfassung

Hintergrund und Zweck Die Ätiologie des Keratokonus (KK) ist multifaktoriell, letztendlich aber bislang unklar. Einige frühere klinische Beobachtungen legen nahe, dass die Hypothyreose eine Rolle bei der Entstehung und Ausprägung des KK spielt. Das Ziel unserer Studie war es, die tomografischen und biomechanischen Parameter zwischen KK-Patienten mit und ohne Hypothyreose zu vergleichen.

Methoden 28 Patienten mit KK und Hypothyreose (Gruppe HT) und 56 KK-Patienten ohne Schilddrüsenfunktionsstörung (Gruppe WHT), die geschlechts- und altersmäßig übereinstimmten, wurden analysiert. Das Durchschnittsalter betrug 40,3 Jahre (von 14 bis 57) in der Gruppe HT und 40,3 Jahre (von 14 bis 57) in der Gruppe WHT. Die ophthalmologischen Routineuntersuchungen bestanden aus Hornhauttomografie und biomechanischen Parametern. Wir analysierten die folgenden KK-Parameter aus der Pentacam (Pentacam HR, Oculus, Wetzlar, Deutschland): Keratokonusindex (KI), steilster Krümmungsradius (K_max), Astigmatismus und minimale Hornhautdicke sowie aus dem Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments, Depew, NY, USA) die korneale Hysterese (CH), den kornealen Resistance-Faktor (CRF) sowie den Keratokonus-Match-Index (KMI).

Ergebnisse Die Ergebnisse der tomografischen und biomechanischen Werte zeigten sowohl in der Querschnitts- als auch in der Längsschnittanalyse keine signifikanten Unterschiede zwischen der HT- und WHT-Gruppe.

Schlussfolgerung Die Schwere des KK scheint, basierend auf biomechanischen und tomografischen Parametern, nicht von der Hypothyreose beeinflusst zu sein.

Key words

cornea - hypothyroidism - keratoconus - thyroid dysfunction - keratoconus severity

Schlüsselwörter

Kornea - Keratokonus - Hypothyreose - Schilddrüsenunterfunktion - Schweregrad des Keratokonus

Publication History

Received: 14 June 2021

Accepted: 24 August 2021

Article published online:
08 November 2021

• References

• 1 Nottingham J. Practical observations on conical cornea: and on the short sight, and other defects of vision connected with it. London, UK: Churchill; 1854
• 2 Rabinowitz YS. Keratoconus. Surv Ophthalmol 1998; 42: 297-319
• 3 Appelbaum A. Keratoconus. Arch Ophthalmol 1936; 15: 900-921
• 4 King EF. Keratoconus following thyroidectomy. Trans Ophthalmol Soc U K 1953; 73: 31-39
• 5 Lee R, Hafezi F, Randleman JB. Bilateral keratoconus induced by secondary hypothyroidism after radioactive iodine therapy. J Refract Surg 2018; 34: 351-353 DOI: 10.3928/1081597X-20171031-02.
• 6 Fisher DA, Sack J, Oddie TH. et al. Serum T4, TBG, T3 uptake, T3, reverse T3, and TSH concentrations in children 1 to 15 years of age. J Clin Endocrinol Metab 1977; 45: 191-198 DOI: 10.1210/jcem-45-2-191.
• 7 Gatzioufas Z, Thanos S. Acute keratoconus induced by hypothyroxinemia during pregnancy. J Endocrinol Invest 2008; 31: 262-266 DOI: 10.1007/BF03345600.
• 8 Hoogewoud F, Gatzioufas Z, Hafezi F. Transitory topographical variations in keratoconus during pregnancy. J Refract Surg 2013; 29: 144-146 DOI: 10.3928/1081597X-20130117-11.
• 9 Soeters N, Tahzib NG, Bakker L. et al. Two cases of keratoconus diagnosed after pregnancy. Optom Vis Sci 2012; 89: 112-116 DOI: 10.1097/OPX.0b013e318238c3f2.
• 10 Stock RA, Thumé T, Bonamigo EL. Acute corneal hydrops during pregnancy with spontaneous resolution after corneal cross-linking for keratoconus: a case report. J Med Case Rep 2017; 11: 53 DOI: 10.1186/s13256-017-1201-y.
• 11 Gatzioufas Z, Panos GD, Gkaragkani E. et al. Recurrence of keratoconus after deep anterior lamellar keratoplasty following pregnancy. Int J Ophthalmol 2017; 10: 1011-1013 DOI: 10.18240/ijo.2017.06.28.
• 12 Bilgihan K, Hondur A, Sul S. et al. Pregnancy-induced progression of keratoconus. Cornea 2011; 30: 991-994 DOI: 10.1097/ICO.0b013e3182068adc.
• 13 Padmanabhan P, Radhakrishnan A, Natarajan R. Pregnancy-triggered iatrogenic (post-laser in situ keratomileusis) corneal ectasia: a case report. Cornea 2010; 29: 569-572 DOI: 10.1097/ICO.0b013e3181bd9f2d.
• 14 Lang GE, Naumann GO. Keratoconus in Alagille syndrome. Klin Monbl Augenheilkd 1991; 198: 555-557 DOI: 10.1055/s-2008-1046031.
• 15 Stoiber J, Muss W, Ruckhofer J. et al. Acute keratoconus with perforation in a patient with Downʼs syndrome. Br J Ophthalmol 2003; 87: 120
• 16 Conrad AH, Zhang Y, Walker AR. et al. Thyroxine affects expression of KSPG-related genes, the carbonic anhydrase II gene, and KS sulfation in the embryonic chicken cornea. Invest Ophthalmol Vis Sci 2006; 47: 120 DOI: 10.1167/iovs.05-0806.
• 17 Coulombre AJ, Coulombre JL. Corneal development. I. Corneal transparency. J Cell Comp Physiol 1958; 51: 1-11 DOI: 10.1002/jcp.1030510102.
• 18 Coulombre AJ, Coulombre JL. Corneal development. III. The role of the thyroid in dehydration and the development of transparency. Exp Eye Res 1964; 3: 105-114 DOI: 10.1016/S0014-4835(64)80024-5.
• 19 Masterson E, Edelhauser HF, Van Horn DL. The role of thyroid hormone in the development of the chick corneal endothelium and epithelium. Invest Ophthalmol Vis Sci 1977; 16: 105-115
• 20 Dias AC, Módulo CM, Jorge AG. et al. Influence of thyroid hormone on thyroid hormone receptor β-1 expression and lacrimal gland and ocular surface morphology. Invest Ophthalmol Vis Sci 2007; 48: 3038-3042 DOI: 10.1167/iovs.06-1309.
• 21 Thanos S, Oellers P, Meyer Zu Hörste M. et al. Role of thyroxine in the development of keratoconus. Cornea 2016; 35: 1338-1346 DOI: 10.1097/ICO.0000000000000988.
• 22 Kahán IL, Varsányi-Nagy M, Tóth M. et al. The possible role of tear fluid thyroxine in keratoconus development. Exp Eye Res 1990; 50: 339-343 DOI: 10.1016/0014-4835(90)90134-g.
• 23 Stachon T, Stachon A, Hartmann U. et al. Urea, Uric Acid, Prolactin and fT4 Concentrations in Aqueous Humor of Keratoconus Patients. Curr Eye Res 2017; 42: 842-846 DOI: 10.1080/02713683.2016.1256413.
• 24 Goebels S, Seitz B, Langenbucher A. Diagnostik und stadiengerechte Therapie des Keratokonus: Eine Einführung in das Homburger Keratokonuscenter (HKC). Ophthalmologe 2013; 110: 808-809 DOI: 10.1007/s00347-013-2917-8.
• 25 Goldich Y, Barkana Y, Gerber Y. et al. Effect of diabetes mellitus on biomechanical parameters of the cornea. J Cataract Refract Surg 2009; 35: 715-719 DOI: 10.1016/j.jcrs.2008.12.013.
• 26 Universitätsklinikum des Saarlandes UKS in Homburg/Saar. Zentrallabor, Referenzwerte. 2016 Accessed January 15, 2021 at: http://www.uniklinikum-saarland.de/de/einrichtungen/kliniken-institute/zentrallabor/analysenspektrum_und_referenzwerte/
• 27 Eppig T, Spira-Eppig C, Goebels S. et al. Asymmetry between left and right eyes in keratoconus patients increases with the severity of the worse eye. Curr Eye Res 2018; 43: 848-855 DOI: 10.1080/02713683.2018.1451545.
• 28 Flaskó Z, Zemova E, Eppig T. et al. Hypothyroidism is not associated with keratoconus disease: analysis of 626 subjects. J Ophthalmol 2019; 2019: 3268595 DOI: 10.1155/2019/3268595.
• 29 Alhawari HH, Khader YS, Alhawari HH. et al. Autoimmune Thyroid Disease and Keratoconus: Is There an Association?. Int J Endocrinol 2018; 2018: 7907512 DOI: 10.1155/2018/7907512.
• 30 El-Massry A, Doheim MF, Iqbal M. et al. Association Between Keratoconus and Thyroid Gland Dysfunction: A Cross-Sectional Case-Control Study. J Refract Surg 2020; 36: 253-257 DOI: 10.3928/1081597X-20200226-03.
• 31 Garmendia Madariaga A, Santos Palacios S, Guillén-Grima F. et al. The incidence and prevalence of thyroid dysfunction in Europe: a meta-analysis. J Clin Endocrinol Metab 2014; 99: 923-931 DOI: 10.1210/jc.2013-2409.
• 32 Gatzioufas Z, Panos GD, Brugnolli E. et al. Corneal topographical and biomechanical variations associated with hypothyroidism. J Refract Surg 2014; 30: 78-79 DOI: 10.3928/1081597X-20140120-01.