To start with, full disclosure : this is a controversial topic. The majority of eye surgeons are still convinced that there is a genetic predisposition to keratoconus, and that eye rubbing is an optional trigger. Other (a growing number) think that this is the sole responsible of keratoconus.

My mentor is the main proponent of the eye rubbing theory. I was a skeptic, and became convinced by learning with him how to properly interview patients on this subject, how to prevent eye rubbing, and by seeing the absence of progression after full awareness of the patients (without cross-linking. We don't do any CXL in my department, ever. KC screening and care is one of our main activity: not doing CXL is a financial loss). My mentor's website : https://www.gatinel.com/recherche-formation/keratocone-2/no-... (No conflict of interest except loyalty).

The main difficulty is that it is almost impossible to design an experiment to prove the theory (if someone has a genius idea, please don't hesitate). Usually other surgeons or students become convinced after visiting the department and spread the good practices back home : still a long way to go.

The harmful eye rubbing is made with the hard parts of the hand (knuckles). It is frequently nocturnal and almost everytime ignored. Awareness comes when the patient has been informed and told to look for this habit. At the second consultation, the eye rubbing is reported in the vast majority of cases. I count the keratoconus patients that deny eye rubbing after 2-3 consultations on one hand. We prescribe a transparent eye shell to sleep with when the patient denies eye rubbing : it allows them to realize that they rub during the night. We prescribe eye drops to ease the eye irritation which triggers rubbing, and instruct to rub the inner part of the eyelid, against the nose (no eye deformation) if necessary. Sleep position is frequently pathological too (eye vs hand or arm contact. In those cases the KC is very asymetrical).

Doctors in our team can predict the eye rubbing habit frequency and intensity by looking at a corneal topography. It is incredible that the role of this habit was ignored so long. I suppose that we doctors don't talk enough with our patients. The financial incentive of performing CXL and surgeries is so clearly detrimental the the adoption of those practices.