In addition to the well-known association between drinking alcohol and various systemic problems, it turns out that ocular issues such as dry eye are a consequence too, as noted in the DEWS II report. Delving further into this relationship, new research published in Eye & Contact Lens suggests the depressant can also cause complications in the tear film and ocular surface within hours of consumption.
The study enrolled 44 eyes of 22 non-smoking, healthy subjects who were approximately 35 years old. Participants were divided into two groups: the first consisted of 17 males and five females who drank 200mL of 25% Japanese vodka (shochu), and the control group included 22 age- and sex-matched participants who consumed water. Subjects were asked to refrain from drinking alcohol the previous day and eating food six hours before testing. Each participant in the study group ate the same dinner and drank the same amount of alcohol over the same time period. Researchers evaluated different metrics prior to testing and again at two and 12 hours after drinking alcohol or water.
As expected, the breath alcohol level was significantly higher in the study group compared with controls after both follow-ups. After 12 hours, the tear evaporation rate increased significantly, while tear breakup time shortened dramatically from about 15 to five seconds in the study group. Lipid layer interferometry showed signs of tear film thinning after 12 hours in each participant consuming alcohol but in no one drinking water. The blink rates increased significantly from 11 blinks per minute to 14 blinks per minute after two hours and 15 blinks per minute at the 12-hour follow-up in the study group. Also in the study group, Schirmer’s scores showed a marked decrease after 12 hours. Of note, the visual analog scale score for dryness significantly increased from baseline to 12 hours in this group. Investigators reported no significant time-wise changes in tear function in controls.
“It is our belief that alcohol intake induces increased tear evaporation due to dehydration, causing an increase in tear osmolarity,” the researchers wrote in their paper. “Although the tear osmolarity has not been assessed in this study, a possible increase in osmolarity is expected to cause dry eye symptomatology.”
The study was supported by a research grant from Johnson & Johnson. The authors had no conflicts of interest to disclose.
Simsek C, Kojim T, Dogru M, et al. The early effects of alcohol consumption on functional visual acuity, tear functions, and the ocular surface. Eye Contact Lens. July 20, 2020. [Epub ahead of print].