Purpose:
Environmental influences play a notable role in the development of the most prevalent refractive error, myopia. Recent investigations highlight the impact of nearwork and stressful lifestyle as important determinants in the incidence of this condition. The present investigation examined whether acute psychosocial stress (induced by a graded oral presentation) contributes to the myopic shift previously observed to occur over the course of a 3-year degree.
Methods:
Part 1). The relationship between demographic characteristics, visual acuity and refractive state (Shin-Nippon Auto Refkeratometer) of first year (Mean Age = 19.20) and senior year (Mean Age = 21.74) Australian University students was first examined (n = 164). Part 2). Changes in sympathetic nervous system activation (indicated by heart rate, salivary cortisol, systolic and diastolic blood pressure (BP)), intraocular pressure (IOP) (Applanation Tonometer) and refractive state was measured in first year students at baseline and following acute stress in the form of an assessed oral presentation two weeks later (n = 44).
Results:
Part 1). The refractive state of the senior cohort was significantly more myopic in comparison to first years, and was associated with greater amounts of near work but not outdoor activity. No difference between the degree of myopia for participants with and without a family history of myopia was observed. Part 2). Levels of myopia significantly increased following acute stress (p < 0.05), in conjunction with elevated cortisol levels and an increase in IOP. A significant correlation between BP and subjective stress rating, between cortisol and heart rate, and between cortisol and IOP was found (p < 0.05).
Conclusions:
A psychosocially stressful event contributed to an acute myopic shift in refraction in young adults undertaking tertiary study. These results suggest that acute psychological stress may play a role in driving environmentally derived refractive errors. Whether these shifts in response to acute stress are transient or permanent remains to be tested.
Keywords: refractive error development • stress response • clinical (human) or epidemiologic studies: prevalence/incidence