Dynamics of outflow easiness coefficient after angular-suprachoroidal drainage in patients with primary glaucoma

Abstract

The problem of long-term intraocular pressure compensation achievement after surgical treatment of primary glaucoma, especially refractory forms, is one of the most topical modern ophthalmology problems. Despite the quite broad and diverse glaucoma interventions arsenal, universal operation, allowing to achieve sustained intraocular pressure reduction while minimizing operational risk and complication rates is still not developed. Most of the described surgical procedures, mainly directed to creating of the additional unnatural intraocular fluid ways that leads to excessive operations zone scarring, early filtering capacity decrease and, consequently, deterioration of intraocular fluid outflow with recurrent intraocular pressure increase in the remote period. To solve the problem, we have proposed a new modified glaucoma treatment method, comprising additional natural uveoscleral outflow pathway surgical activation by angular-suprachoroidal drainage, and examined the hypotensive action duration of this operation, analyzed the outflow easiness coefficient dynamics in the remote period.

The aim of the study: to explore the outflow easiness coefficient dynamics of intraocular fluid before and after angular-suprachoroidal drainage in patients with primary glaucoma.

Patients and methods: 51 primary glaucoma patient’s treatment results (54 eyes, 28-89 y. o., mean age – 67,5±13,4) were analyzed. Men was– 26 (52,0 %), women – 28 (48,0 %). All glaucoma patients were surgically treated by additional natural uveoscleral outflow pathway surgical activation with angular-suprachoroidal drainage after implantation of collagenous drain Xenoplast on our proposed method (patent of Ukraine № 46521 from 25.12.2009). In all patients primary open angle glaucoma is diagnosed in 50 (92,6%) eyes, narrow anterior chamber angle glaucoma in 4 (7,4%) eyes. Primary glaucoma patients had initial stage in 6 (11,1%) eyes, developed - in 9 (16,7%), advanced - in 16 (29,6%) and terminal - in 23 eyes (42,6 %). Moderately elevated intraocular pressure was diagnosed in 32 (59,3%) eyes, high – in 22 (40,7%) eyes. The diagnosis of glaucoma was confirmed on the basis of clinical and ophthalmological examinations. Ophthalmic examination included tonometry, tonography, visual acuity by the Golovin-Sivtsev table, gonioscopy, biomicroscopy, ophthalmoscopy, visual field study. Exams were made during 2 years: in the early postoperative period (1 month) and at 6, 12, 24 months after surgery. All results were compared with preoperative data.

Results. In the early and remote postoperative period (up to 24 months) all patients had statistically valid intraocular pressure decrease and outflow easiness coefficient increase. Before the surgery True intraocular pressure index (P₀) had averaged 31,1 ± 6,7 mm of mercury, Outflow easiness coefficient – 0,1 ± 0,04 mm³/min/mm of mercury in primary glaucoma patients. In 1 month after the surgery intraocular pressure (P₀) and Outflow easiness coefficient improved and averaged 17,7 ± 2,7 mm of mercury and 0,22 ± 0,03 mm³/min/mm of mercury respectively. In 6, 12 and 24 months these indexes remained almost unchanged and corresponded to the normal values. Correlation analysis between Outflow easiness coefficient 2 years after the operation and True intraocular pressure (P₀) before surgery revealed no statistical linear dependence. Linear statistical correlation absence between Outflow easiness coefficient 2 years after the surgery and the primary glaucoma stage in operated patients observed. Statistically significant linear correlation absence proves the failure of dependence between Outflow easiness coefficient after surgery (hence the intraocular liquid outflow state) and preoperative intraocular pressure with the primary glaucoma stage in operated patients. At the same time Outflow easiness coefficient indexes in patients with different primary glaucoma stages 2 years after surgery were not statistically different and not reduced to pathological level. Similar pattern in comparison of the remote period (2 years after surgery) Outflow easiness coefficient in patients with moderately elevated and high preoperative intraocular pressure was marked. This proves the possibility and sufficient efficiency of angular-suprachoroidal drainage with collagenous drain Xenoplast implantation by our proposed method in all patients with primary glaucoma, regardless of its stage and the level of intraocular pressure before surgery.

Thus, in all different primary glaucoma stages patients with non compensated intraocular pressure on the antihypertensive therapy before the surgery the application of the proposed surgical method succeeded in achieving good hypotensive effect without need of post-operative medical treatment in 35 eyes (64,8 %). Compensation of intraocular pressure after surgery was achieved by the additional antihypertensive droplets use in 19 eyes (35,2 %). Patients with decompensated intraocular pressure during 24 months after operation were not observed.

Сonclusion.

1. Surgical natural uveoscleral outflow activation method by angular-suprachoroidal drainage with collagenous drain Xenoplast implantation on the proposed technique allows to achieve stable Outflow easiness coefficient indexes improvement in the remote postoperative period in patients with primary glaucoma, regardless of its stage and the increase of preoperative intraocular pressure level.
2. Use of the proposed technique provides long hypotensive effect explained by persistent high effective intraocular fluid outflow and evidenced by the Outflow easiness coefficient dynamics.
3. Proposed operation of angular-suprachoroidal drainage with collagenous drain Xenoplast implantation enabled to achieve postoperative intraocular pressure compensation without the drug treatment use for 35 eyes (64,8%) and with the additional use of antihypertensive drops in 19 eyes (35,2%), which accounted for 100,0% of the operated primary glaucoma patients.
4. Our proposed surgical primary glaucoma treatment method experience emphasizes the need of active surgical tactics and allows to recommend the operation in the early stages of the glaucomatous process.