Ab-externo glaucoma surgery with 308 nm excimer laser (experimental and clinical study)

Session Details

Session Title: Glaucoma II

Session Date/Time: Monday 15/09/2014 | 08:00-10:30

Paper Time: 08:37

Venue: Boulevard F (Level 1)

First Author: : I.Iskakov RUSSIA

Co Author(s): :    V. Chernykh   O. Ermakova   A. Razev   D. Churkin   E. Kargapoltcev  

Abstract Details

Purpose:

To develop safe, clinically effective and easy-to-use in clinical practice technology of glaucoma surgery with 308 nm excimer laser.

Setting:

Multidisciplinary Science and Technology Complex Eye Microsurgery named after Academician S. N. Fyodorov, Federal State Institution, Novosibirsk Branch, Russia

Methods:

Experimental part was carried out with scleral tissue of isolated human eye using 3 wavelengths: 248, 308 and 353 nm generated by three specially designed excimer laser (EL) systems. Ablation threshold and speed for studied wavelengths were introduced. Ultraviolet-rays penetration spectrum of sclera, distilled water and balanced solution, the effect of 248, 308 and 353 nm waves to morphological structure of sclera was also studied. To deliver 308 nm to the surgical field, flexible fiber light guide with easy-to-use handle was used. 16 eyes of 16 patients with open angle glaucoma were operated. Steps of surgery included: conjunctival incision; outline forming of surface and deep scleral flap with knife; 308 nm EL flaps separation, ablation of deep flap of sclera and outer trabecular tissue; gradual thinning of trabecular tissue to get a sufficient filtration of intraocular fluid. Follow up term is 3-12 months. Visual acuity, visual field, intraocular pressure, ultrasound biomicroscopy were examined.

Results:

Waves with less than 300 nm length are significantly absorbed by superficial sclera layers. Penetration capacity gradually increases with wave lengthening. 308 nm EL has intermediate ablation speed. Absorption by balanced solution of UV (190-400 nm) is substantially decreases and penetration spectrum – increases. Intraocular fluid does not block ablation of sclera under exposure of 308 nm EL. The exposures of studied EL wavelengths to morphological structure of sclera have no any coagulate damage and other pathological changes. After surgery all patients reached stable decrease of intraocular pressure. Outflow tract is completely functioning which results in stable visual functions in all treated eyes.

Conclusions:

The optimal EL wavelength for performing ab-externo glaucoma surgery is 308 nm. The developed ab-externo method of glaucoma surgery combines minimal invasion, safety and clinical efficacy.

Financial Interest:

NONE