Investigating the Use of Pilocarpine, Timolol, and Prostaglandin Analogues in English Publications

Purpose: This study aimed to investigate the changes in the relative frequencies of the words "pilocarpine," "timolol," and "prostaglandin analogues (i.e., latanoprost, bimatoprost, travoprost, and tafluprost)" over a period of 1.5 centuries in a large corpus of English-language literature.Methods: A corpus of words from English language books published between 1860 and 2019 was searched using an online tool, the Google Ngram Viewer.The words "pilocarpine," "timolol," "latanoprost," "bimatoprost," "travoprost," and "tafluprost" were entered into the Google Ngram Viewer in case-insensitive mode, with the default smoothing value of three accepted.Results: Upon comparison of the frequencies of the six words over a period of 1.5 centuries, a notable pattern was revealed.From the early 1900s to the mid-1900s, the level of interest in "pilocarpine" declined, whereas from 1965, the interest in "Timolol" rapidly increased.However, with the emergence of words for prostaglandin analogues in the 1990s, the interest in both "pilocarpine" and "Timolol" began to decrease again.Conclusions: This dataset enables us to draw inferences regarding the changing interest in anti-glaucoma medications over the course of one and a half centuries, demonstrated by charting the relative frequency of words from Google Ngram database.