Ординатура / Офтальмология / Английские материалы / Clinical Pathways in Glaucoma_Zimmerman, Kooner_2001

540 Management of Blind, Painful Eye from Glaucoma

pain is secondary to a surface disease, then frequent corneal lubrication should be the treatment of choice. If a band keratopathy is present, one may consider chelation, although more aggressive surgical treatment may be appropriate.

Does Cyclocryotherapy Work?

Freezing of the ciliary body as a treatment of increased IOP has been well studied and extensively reported in the literature.22–23 It can be used in refractory cases. The preferred approach is to treat 180 degrees of the ciliary body at a time. Most surgeons prefer a double freeze-thaw technique. The usual parameters are 80°C for 1 minute. The treatment consists of applying the cryoprobe 2 to 3 mm posterior to the limbus so as to create an iceball that just overlies the limbus. The aim is to cause the least amount of damage to functional trabecular meshwork. It is important to avoid the 3 and 9 o’clock positions, so that the two long posterior ciliary arteries are not damaged. About four or five partially overlapping cryoburns are usually sufficient. Cyclocryotherapy is highly efficacious and may be repeated if the result is unsatisfactory. Complications include persistent hypotony with extensive atrophy of the ciliary body, and the eye may end up as phthisis bulbi. Cyclocryotherapy may also prolong or induce intraocular inflammation. There have been a few cases reported in the literature of sympathetic ophthalmia, which could be devastating to the fellow eye, and hence, the patient should be warned of this potential complication.24,25

Does Laser Cyclodestruction Work?

Neodymium:yttrium-alumninum-garnet (Nd:YAG) laser has been reported as a treatment of high IOP, both in seeing and nonseeing eyes.26–28 Al-Ghamdi et al29 treated 47 patients with Nd:YAG laser, with the mean IOP dropping from 40.5 to 15.6 mm Hg. The treatment was performed after retrobulbar anesthesia, by applying laser burns 2 to 3 mm posterior to the limbus. A mean of 28 burns were applied with an average energy of 6 joules. Complications included intraocular inflammation, hypopyon, hyphema, hypotony, choroidal detachment, and flat anterior chamber.

When Should Retrobulbar Neurolytic Agents Be Used?

For a long time retrobulbar alcohol injection was the treatment of choice in blind painful eyes because of the simplicity of its delivery and apparent effectiveness.30 Over the years, more and more potential severe complications were described, which made the procedure less popular. Complications include ptosis and external ophthalmoplegia. Recurrence of the pain is very common, necessitating repeated alcohol injections. Its effect on the orbital tissues is also of concern. Newer neurolytic agents commonly used in pain management have not been tried in the retrobulbar area.

What Is the Surgical Treatment of Blind, Painful Eye from Glaucoma?

In the absence of visual potential, intraocular glaucoma surgery is contraindicated, because of the risk of sympathetic ophthalmia.31 It should also be

542 Management of Blind, Painful Eye from Glaucoma

ophthalmia and are safer in cases of occult or missed intraocular tumors. They also provide better specimens for pathologic examination, which in some cases may reveal important information concerning the pathogenesis of the visual loss in a variety of ocular disorders. Both procedures are generally performed under general anesthesia, but both could be performed under retrobulbar anesthesia, although it is more challenging with enucleations.

What Is the Surgical Technique in Evisceration?

After retrobulbar or general anesthesia, a 360-degree peritomy is performed and dissection in the sub-Tenon’s space is carried out for 3 to 4 mm posterior to the limbus. With a no. 11 blade, a stab incision just posterior to the limbus is made. The cornea with a small rim of sclera is then resected with scissors. An evisceration spoon is then introduced between the uveal tissue and the sclera, and pushed gently posteriorly in the suprachoroidal space. Blunt dissection with the spoon is then carried over 360 degrees, releasing any adhesions between the choroid and the sclera. At this point, the intraocular contents usually present as an intact mass and are carefully evacuated. The specimen is then sent for pathologic examination. Any bleeding can be controlled with simple pressure. The inside of the sclera is then inspected for any residual uveal tissue. It is advisable to strip any remaining uvea from the sclera to minimize any stimulus for sympathetic ophthalmia. Once the sclera is void of uveal tissues, many surgeons introduce cotton wedges soaked with absolute alcohol and gently but thoroughly scrub the inside of the sclera. This may further decrease the possibility of sympathetic ophthalmia, by destroying any uveal tissues that may still remain in the scleral emissura. Care should be taken to prevent any contact of the alcohol with the conjunctiva because of the possibility of significant postoperative chemosis.

An appropriately sized sphere can then be inserted into the scleral pouch and the sclera sutured with multiple interrupted permanent sutures. The size of such a sphere in eviscerations is usually smaller than desired for optimal orbital volume replacement, hence necessitating a larger prosthesis. To be able to put a larger orbital implant, relaxing incisions in the sclera can be made in a vertical fashion starting from anterior to the equator and going all the way posteriorly to just before the optic nerve area.33,35 A circular incision around the optic nerve can be made connecting these vertical incisions. This will cause the scleral pouch to significantly enlarge. A spherical implant of a larger size can then be inserted. Newer implants, such hydroxyapatite or Medpor, have the advantage of allowing vascularization. Hence, they become a living part of the orbit and decrease the potential long-term complications, especially migration of the implant. Tenon’s capsule is then sutured with multiple interrupted 5-0 polypropylene sutures and the conjunctiva closed with a running 6-0 polypropylene suture. A conformer is then placed and a pressure dressing applied. The dressing should not be disturbed for 48 hours. Five weeks following evisceration, a prosthesis may be fitted.

What Is the Surgical Technique for Enucleation?

Enucleations are usually performed under general anesthesia, although retrobulbar anesthesia can be tried in certain patients.41 After a 360-degree

peritomy, dissection is carried out in all of the four cardinal quadrants.42–44 Each rectus muscle is then carefully isolated and disinserted from the globe, after securing a 5-0 polypropylene suture close to the insertion. The superior oblique muscle can be identified and cut. Similarly, the inferior oblique muscle can be isolated, cut, and cauterized. The stump of medial rectus muscle is then secured with a clamp, and the enucleation scissors introduced medial to the globe, directing posteriorly between the medial rectus muscle and the sclera, until the optic nerve is felt and engaged. The tips of the scissors should be directed posteriorly, and while applying pressure anteriorly on the medial rectus stump, the optic nerve is excised. This usually causes immediate protrusion of the globe. Any remaining adhesions between the globe and the orbital tissues are then carefully dissected. Immediate pressure is then applied to the orbit, using a sterile test tube wrapped in gauze. The risk of bleeding can be significantly decreased by first clamping the optic nerve before it is cut. In most cases, bleeding is controlled using a combination of pressure, cautery, and Gelfoam soaked with thrombin. An orbital implant, wrapped in donor sclera, is then introduced into the orbit, and each of the four rectus muscles is sutured to the sclera corresponding to its anatomic position. The rectus muscles can also be sutured directly to the orbital implant without a sclera wrap. A hydroxyapatite or a Medpor implant is preferred because of their ability to promote vascularization and thus decreasing the risk of migration. Tenon’s capsule and conjunctiva are then closed in a manner similar to eviscerations. Similarly, a conformer and a pressure dressing are applied.

What Are the Complications of Evisceration and Enucleation?

The most dreaded intraoperative complication is removal of the wrong eye. This can be prevented by identifying and marking the eye to be operated on preoperatively. The mark should be applied above the correct eye and should be visible in the operative field. Hemorrhage is more common following enucleations, and may be profuse. It is best controlled by applying gauze packing and careful firm pressure following the removal of the globe. Cauterization and thrombin application may also be used appropriately. Injury to the medial orbital wall may be prevented by introducing the enucleation scissors medial to the globe rather than temporal. Similarly, perforation of the globe may be avoided by directing the enucleation scissors posteriorly into the orbit and applying anterior pressure on the media rectus stump. If perforation does occur, every attempt should be made to identify the remaining part of the globe and resecting meticulously. Postoperatively, complications include wound dehiscence with extrusion of the orbital implant. This can be avoided by careful closure of the Tenon’s capsule and conjunctiva in separate layers. Implant migration may be minimized by using hydroxyapatite or Medpor implants. Other complications include ptosis, enophthalmos, shallowing of the fornices, superior sulcus deformity, and orbital cysts.45

What Are the Considerations in Children?

The growth of the orbit in children is dependent on the presence of an enlarging globe. A marked increase in the size of the globe from congenital glaucoma

Index

Page numbers followed by f indicate figures. Page numbers followed by t indicate tables.

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