Aim. To assess the effectiveness of combined non-penetrating surgery: non-penetrating deep sclerectomy and ab externo trabeculectomy in patients with primary open-angle glaucoma depending on type of aqueous humor retention. Methods. Results of surgeries on 72 patients (83 eyes) with primary open-angle glaucoma were analyzed. Patients were divided into 2 groups. Standard ophthalmic examination was added by fluorescein lymphography of the anterior eye to determine the surgery type as well as for hypotensive effect long-term prognosis. Non-penetrating deep sclerectomy and ab externo trabeculectomy were conducted in the first group (67 eyes). In the control group (16 eyes) standard non-penetrating deep sclerectomy was performed. A cytostatic was used as a subconjunctival injections in the post-surgical period. Results. Intraocular pressure was fully compensated in 52 eyes out of 67 (77.6%) in the long-term period after non-penetrating deep sclerectomy and ab externo trabeculectomy in the first group. In 15 eyes (22.4%) topical hypotensive drugs were required for complete compensation of intraocular pressure. Complete compensation of intraocular pressure was registered in patients with moderate aqueous humor flow reduction (trabecular and mixed with prevalence of trabecular forms). Topical hypotensive drugs were required in severe aqueous humor flow reduction (mixed form with prevalence of intrascleral). In the second group, compensation of intraocular pressure was achieved only in early post-surgical period in 12 eyes (75%) with further decrease of hypotensive effect after 4-6 months. There was no complete compensation of intraocular pressure at late post-surgical period. To normalize the intraocular pressure, topical hypotensive drugs were required in 15 eyes (93.8%), surgery was repeated in 1 (6.2%) case. Conclusion. Combined surgery (non-penetrating deep sclerectomy and ab externo trabeculectomy) is more effective compared to non-penetrating deep sclerectomy and is indicated in patients with open-angle glaucoma and moderate aqueous humor flow reduction.