ABSTRACT
[Purpose]Acupuncture stimulation is known to improve visual acuity. Since this improvement was frequently disassociated with refractive change, we determined the mechanism by examining the patients without lens accommodation. <BR>[Methods]Patients (n = 30) receiving cataract surgery in 2005 at Meiji University of Oriental Medicine Hospital were examined (mean age: 73.0). Bilateral LI4, Taiyang and shang-jingming points were stimulated by acupuncture needles for 10 min (acupoints stimulation). On a different day, the same patients received sham points stimulation at 1 cm above or lateral from the above-mentioned acupoints. Both uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) was measured with a logMAR scale at pre-and post-acupuncture stimulations. Furthermore, the patients with improved UCVA and BCVA typically (n = 4) received topical tropicamide eyedrops for suppression of pupil diameter change. UCVA and BCVA were measured at pre-and post-acupuncture stimulation.<BR>[Results]Acupoints stimulation significantly improved both UCVA (0.39 to 0.30, p < 0.0006) and BCVA (0.15 to 0.08, p < 0.0001). Although sham points stimulation also significantly improved both UCVA (0.38 to 0.32, p < 0.02) and BCVA (0.14 to 0.09, p < 0.0001), there was no significant difference in comparison with acupoints stimulation controls. Under mydriasis after tropicamide eyedrops, acupuncture stimulation did not improved UCVA, and the variation of BCVA was significantly different from control (p < 0.013).<BR>[Discussion]Acupuncture stimulation improved UCVA and BCVA even in elderly patients that lack accommodation. Our results imply that as pupil diameter changes, a subsequent pinhole effect may be a critical mechanism for UCVA and BCVA improvement by acupuncture stimulation. In addition, the phenomena are not specific effects of acupoints and imply a response via sensory nerves.