RUDN University doctors have proposed an alternative method of surgical management of glaucoma. The main risk factor of glaucoma is increased pressure in the eye. To reduce it doctors proposed to remove excess fluid from the eye in a new way. The first clinical trials show the success of the technique. The results are published in Vision.
Aqueous humor is a fluid between the cornea of the human eye and the lens. It is needed to nourish and protect the eye, and also affects the refraction of light. Aqueous humor is constantly secreted from certain epithelial cells balanced by the drainage. If the outflow is disturbed, it causes the excessive intraocular pressure, which leads to the development of glaucoma. Increased intraocular pressure is normalized with the help of medications or surgery. However, most methods of treatment are aimed at only one way of outflow of aqueous humor - through the so-called trabecular meshwork. RUDN doctors drew attention to the fact that it is possible to relieve excess pressure by taking a different pathway, and offered the first clinical results of a new surgical technique.
"Both pathways – trabecular and non-trabecular – play an equivalent role in the outflow of aqueous humor, though there is evidence of the non-trabecular pathway carrying up to 60% of the aqueous humor outflow in young people. Known surgical methods in management of glaucoma are focused at creating an artificial pathway for the aqueous humor outflow At the same time, the non-trabecular pathway is the least studied. We have modified the existing surgical technique to improve the outflow by the non-trabecular pathway -; Vinod Kumar, Doctor of Medical Sciences, Professor of the Department of Eye Diseases of RUDN University.
Doctors have proposed a modified version of non-penetrating deep sclerectomy technique. During the operation, the integrity of the eyeball is not violated - in order to facilitate the outflow of fluid, the surgeon does not perforate the eyeball, but only creates an additional reservoir in the outer layer of the eyeball (sclera). The collagen drainage is then implanted there with one end inserted in the suprachoroidal space. If pressure is increased post-op, the surgeon performs YAG laser trabeculotomy, thereby ensuring an unimpeded outflow of intraocular fluid from the anterior chamber into the suprachoroidal space and activates the outflow along the non-trabecular pathway. Unlike the standard technique, when the trabecular outflow pathway is affected, the new approach avoids fibrosis, the most common complication.
The clinical trial involved 50 patients - 17 men and 33 women aged 69 to 84 years. The day after the operation, the intraocular pressure in patients fell on an average more than twice (from 30 mm Hg to 12 mm Hg with a range from 9 to 23 mm Hg) and did not increase significantly in the next six months. The need to take hypotensive medications practically disappeared - the number of medications taken on an average decreased from 2.9 to 0.7.
All surgical steps of this technique are performed without perforation of the eyeball; therefore, all complications associated with a sudden decrease in intraocular pressure are either minimized or completely excluded. Thanks to this technique, no antimetabolites are needed to counteract fibrosis. So far, the study has been conducted on a small series of cases with short-term follow-up. To confirm the efficacy and safety of this method, randomized, controlled and comparative studies with a longer observation period and large groups are needed."
Mikhail Frolov, Doctor of Medical Sciences, Head of the Department of Eye Diseases, RUDN University
Kumar, V., et al. (2022) Bleb-Independent Glaucoma Surgery to Activate the Uveolymphatic Route of Non-Trabecular Aqueous Humor Outflow: Short-Term Clinical and OCT Results. Vision. doi.org/10.3390/vision6010004.