Glaucoma surgery by the natural mimicking method or deep sclerectomy is one technique that uses the principle of draining fluid from the eye and creates a fluid reservoir on the surface of the eyeball similar to the standard method (trabeculectomy). There are two main differences: glaucoma surgery by the natural mimicking method does not create a perforation or connection between the inside and outside of the eye (nonpenetrating filtering procedure), and it creates an additional fluid reservoir in the scleral layer (scleral lake). This reservoir lies beneath the scleral tissue similar to that found in trabeculectomy. Since the fluid reservoir must remain as a channel at all times, special devices or materials to support the space (space maintainer) are always used in conjunction with deep sclerectomy.
Indications for glaucoma surgery by the natural mimicking method (deep sclerectomy) include
- Open-angle glaucoma, both primary and secondary (primary and secondary open angle glaucomas)
- Glaucoma caused by inflammation inside the eye (uveitic glaucoma), where deep sclerectomy causes less inflammation
- Glaucoma in high myopes, who have a high risk of choroidal detachment when operated on by the standard method (trabeculectomy)
Groups that can undergo the procedure but require caution and may have unpredictable outcomes
- Congenital glaucoma
- Narrow-angle glaucoma
- Glaucoma caused by angle trauma (post traumatic angle recession) or previous laser treatment at the angle
Contraindications for glaucoma surgery by the natural mimicking method (deep sclerectomy) include
- Angle-closure glaucoma, both primary and secondary (primary and secondary angle-closure glaucomas)
- Glaucoma caused by abnormal blood vessel growth in the eye (neovascular glaucoma)
- Glaucoma caused by abnormalities of the iris, cornea, and the innermost corneal cells (Iridocorneal endothelial syndrome, ICE)
ESNOPER CLIP or ESNOPER CLIP uveoscleral implant (AJL OPHTHALMIC, S.A., Vitoria-Gasteiz, Araba, Spain) is a special device used for glaucoma surgery by the natural mimicking method (deep sclerectomy) in patients with open-angle glaucoma. It is made from a nonionic polymer of 2-hydroxyethyl methacrylate (HEMA) to prevent protein adhesion on the surface. It is insoluble, thin, transparent, trapezoid-shaped, and flexible (Image A), measuring 5.50 x 1.30 x 2.20 millimeters and 0.2 millimeters thick. It has three built-in drainage holes that help increase the outflow of aqueous humor from the anterior chamber of the eye to the outside through all pathways, including the normal mechanisms, which are intrascleral and the supraciliary space, as well as the accessory uveoscleral outflow pathway by permeating various tissues.
When folded in half, the lower part of the ESNOPER CLIP has a side notch (notched plate) and is inserted at the suprachoroidal space. The notch helps prevent the ESNOPER CLIP from moving, so there is no need to suture the device to attach it to the eye tissue. The upper part rests at the base of the fluid reservoir in the scleral layer (scleral lake) to maintain the reservoir as a channel and assist in fluid drainage.
ESNOPER CLIP is packaged in a sterile glass vial (Image B) with tweezers and immersed in highly purified water to maintain moisture. It has a shelf life of 3 years from the manufacturing date and carries the CE 2797 mark certifying safety, health, and environmental protection standards according to European Union (EU) regulations in Europe.
Dr. Natamon Srisamran
Glaucoma Specialist Ophthalmologist
Eye and Laser Center, Phyathai 1 Hospital
