Assessment of the mechanical forces applied during eye rubbing

Farhad Hafezi; Nikki L Hafezi; Bojan Pajic; Francesca Gilardoni; J Bradley Randleman; Jose Alvaro P Gomes; Léonard Kollros; Mark Hillen; Emilio A Torres-Netto

doi:10.1186/s12886-020-01551-5

Assessment of the mechanical forces applied during eye rubbing

BMC Ophthalmol. 2020 Jul 22;20(1):301. doi: 10.1186/s12886-020-01551-5.

Authors

Farhad Hafezi^{1

2

3

4

5}, Nikki L Hafezi⁶, Bojan Pajic^{7

8

9

10}, Francesca Gilardoni^{11

6}, J Bradley Randleman¹², Jose Alvaro P Gomes¹³, Léonard Kollros⁶, Mark Hillen⁶, Emilio A Torres-Netto^{11

6

13}

Affiliations

¹ Laboratory for Ocular Cell Biology, Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland. farhad@hafezi.ch.
² ELZA Institute, Dietikon, Switzerland. farhad@hafezi.ch.
³ USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA. farhad@hafezi.ch.
⁴ Faculty of Medicine, University of Geneva, Geneva, Switzerland. farhad@hafezi.ch.
⁵ Department of Ophthalmology, University of Wenzhou, Wenzhou, China. farhad@hafezi.ch.
⁶ ELZA Institute, Dietikon, Switzerland.
⁷ Faculty of Medicine, University of Geneva, Geneva, Switzerland.
⁸ ORASIS Eye Clinic, Swiss Eye Research Foundation, Reinach, Switzerland.
⁹ Department of Physics, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia.
¹⁰ Faculty of Medicine of the Military Medical academy, University of Defense, Belgrade, Serbia.
¹¹ Laboratory for Ocular Cell Biology, Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland.
¹² The Cleveland Clinic, Clevelan, OH, USA.
¹³ Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil.

Abstract

Background: To determine the average amount of mechanical forces applied to the lids of keratoconus patients during eye rubbing.

Methods: Fifty-seven patients (41 male, 16 female, average age 34.8 years) with a clinically and topographically diagnosed keratoconus and a history of eye rubbing were prospectively asked to perform their individual eye rubbing movement on a high-precision balance. The type of eye-rubbing movement and the force applied, represented in newtons (N), were recorded and analyzed.

Results: We detected three different types of eye rubbing. Rubbing with the fingertip was most frequent (51%), followed by rubbing with the knuckle (44%) and rubbing with the fingernail (6%). Each type of eye rubbing showed different average forces, with knuckle type eye rubbing applying significantly more force (9.6 ± 6.3 N) on the lids than fingertip (4.3 ± 3.1 N) and fingernail (2.6 ± 3.3 N) types (p < 0,001 and p = 0,016, respectively).

Conclusions: There were major variations in the force exerted on the lids, depending on the type of eye rubbing employed. This data will help determine the forces that need to be applied in future experimental eye rubbing models.

Keywords: Corneal biomechanics; Eye rubbing; Keratoconus.

MeSH terms

Adult
Eye
Female
Humans
Keratoconus*
Male