Review: Eye Rubbing Techniques Raise Corneal Temperature in Healthy Young Adults

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medRxiv Published April 30, 2026 Medically reviewed April 30, 2026 Study authors: Karaatli, M.; Yalcin, M.; Eroglu, S.; Ozalp, O.; Atalay, E. DOI ↗ By Dr. Lars van Dijk, PhD · Surgical, Procedural & Diagnostic

Key Takeaway

Interpret eye rubbing as a cause of transient corneal temperature rise, but clinical relevance is unclear.

This cross-sectional experimental study investigated the effect of different eye rubbing techniques on corneal surface temperature in 93 healthy individuals aged 19-29 years with no ocular pathology, conducted at Eskisehir Osmangazi University. The interventions included fingertip, knuckle, and fingernail eye rubbing, with corneal temperature measured before and after rubbing.

All three techniques produced significant increases in corneal temperature: fingertip (1.02 ± 0.58°C, p<0.001), knuckle (1.03 ± 0.54°C, p<0.001), and fingernail (1.12 ± 0.52°C, p<0.001). However, no significant differences were found between the techniques (p>0.05). Age showed a negative correlation with temperature increase, significant only for fingertip after FDR correction (p<0.001). Corneal asymmetry (IHA) correlated positively with temperature increase for fingertip (p=0.003) and knuckle (p<0.001). Eye closure alone contributed approximately 0.6°C of every 1°C rise.

Limitations include the lack of reported adverse events, funding sources, and practice relevance. The study does not establish causality or clinical significance. As a cross-sectional experimental study, findings are preliminary and require confirmation in larger, more diverse populations.

Clinicians should note that eye rubbing transiently increases corneal temperature, but the clinical implications remain uncertain. The study does not address long-term effects or pathological conditions.

Study Details

EvidenceLevel 5

PublishedApr 2026

View Original Abstract ↓

Purpose: To characterize corneal surface temperature changes induced by different eye-rubbing techniques in healthy individuals and to investigate the factors influencing temperature change. Setting: Eskisehir Osmangazi University Design: Cross-sectional experimental study Methods: This study included 93 healthy volunteers aged 19-29 years with no ocular pathology. Participants performed three eye-rubbing techniques-fingertip, knuckle, and fingernail rubbing- while corneal temperatures were recorded with a high-resolution thermal camera (FLIR A8200sc, Teledyne FLIR Systems Inc., Boston MA, USA). Subjects rubbed their eyes for 20 seconds with their dominant hand. Linear mixed-effects models were used to compare corneal temperature before and after eye rubbing and to examine the effect of covariates. Results: All eye rubbing techniques significantly increased corneal temperature (fingertip: 1.02 +/- 0.58 degrees Celsius, knuckle: 1.03 +/- 0.54 degrees Celsius, fingernail: 1.12 +/- 0.52 degrees Celsius; all p<0.001), with no significant differences between techniques (p>0.05). Age showed a negative correlation with corneal temperature increase across all rubbing methods (all unadjusted p<0.05), remaining significant only for the fingertip technique after FDR correction (p<0.001). IHA correlated positively with temperature increase for fingertip and knuckle rubbing after FDR adjustment (p= 0.003 and <0.001, respectively). The subgroup analysis indicated that approximately 0.6 degrees Celsius of every 1 degrees Celsius rise in corneal temperature could be attributed to eye closure alone, while the remainder was likely due to mechanical effects of eye rubbing. Conclusion: Fingertip, knuckle, and fingernail rubbing each produced a transient but significant rise of approximately 1 degree Celsius in corneal temperature. Greater temperature elevation was associated with younger age and higher corneal asymmetry.