Vision impairment occurs when an eye condition affects the visual system and one or more of its vision functions. According to the World Health Organization (WHO), the global prevalence of vision impairment is at least 2.2 billion people. In our previous studies, supplementation of Cordyceps cicadae mycelium (CCM), with N6-(2-hydroxyethyl) adenosine (HEA) as its bioactive component, has shown to exert eye protective effects including that of lowered intraocular pressure, amelioration of dry eye symptoms and prevention of UVB-induced cataract formation. However, the correlation between CCM and vision acuity improvement still remains unknown. In this clinical study, a total of 60 individuals (20 males, 40 females; 20-25 years old) were recruited, receiving 500 mg/day of CCM for a period of 28 days. Measurements on visual acuity, axial length, and corneal astigmatism changes were taken at different timepoints. Ocular surface disease index (OSDI) and computer vision syndrome (CVS) questionnaires were also performed. Results showed that visual acuity was improved by -0.05 logMAR at 1h after CCM intake and -0.1 logMAR at day 28 when compared to baseline (n = 60). From the OSDI and CVS questionnaires, average eye fatigue score was significantly reduced from 22.05 to 18.16. These findings suggest that CCM is effective in relieving eye fatigue and thereby improving visual acuity. This gives an insight for the novel application of CCM on pseudomyopia or other related ocular diseases.