Background: Reducing intraocular pressure (IOP) was only established method to limit rate at which damage progresses in glaucoma, a chronic, multifactorial optic neuropathy. Objectives: This study aimed to determine how transscleral subthreshold diode laser treatment [photobiomodulation (PBM)] affects individuals with primary open angle glaucoma. Subjects and methods: Ophthalmology departments, Clinics at Bab El-Shariyia University Hospital, El-Zahraa University Hospital in Cairo, Egypt, respectively, served as study's locations. Thirty eyes from nineteen individuals with primary open angle glaucoma, and a visual field impairment were included in this study. Result: There was statistically significant improvement in the studied group regarding best-corrected visual acuity (BCVA) before and after intervention. There was highly statistically significance decrease in the intraocular pressure of patients before and after intervention in the studied group and significant improvement of visual field before and after intervention. Conclusion: Micro pulse diode laser was a safe, efficient treatment for glaucoma, according to results of our study. BCVA and a highly statistically significant drop in intraocular pressure were outcomes of intervention. Visual field improved statistically significantly, as seen by decreases in mean deviation (MD), pattern standard deviation (PSD) prior to, and following intervention.