Digit Preference in Goldmann Applanation Tonometry: The Hedgehog Effect

Purpoe Digit preference i a ubconciou bia toward number that end in certain digit. We conducted a tudy to ae for digit preference in intraocular preure meaurement uing the Goldmann applanation tonometer. Deign Propective tudy with maked and unmaked phae. Method The tudy wa conducted in general ophthalmic clinic in a Ditrict General Hopital in Blackpool, United Kingdom, by 6 clinical ophthalmologit. Conecutive right eye intraocular preure meaurement were collected for a 2-month period for the maked phae and were repeated for the unmaked phae. The proportion of even number wa the main outcome meaure. Reult ix ophthalmologit completed both phae: 555 of 917 reading were even in the maked phae (P = .075), and 679 of 1056 reading were even in the unmaked phae (P = .022). Concluion Our reult ugget that digit preference influence meaurement from the Goldmann applanation tonometer and that thi perit when oberver are aware of digit preference. Thi bia may influence both clinical deciion-making and trial reult.