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

Publikationsverlauf

Eingereicht: 14. Juni 2021

Angenommen: 24. August 2021

Artikel online veröffentlicht:
08. November 2021

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