**7. Laser treatment**

#### **7.1. Laser iridotomy**

Laser iridotomy is indicated for all cases of secondary papillary block glaucoma, chronic an‐ gle closure glaucoma and prophylactically when progressive anterior synechiae are being formed. [38] It is performed either to allow aqueous humour access into the anterior cham‐ ber in papillary block glaucoma or increase in the depth of the anterior chamber in chronic angle closure glaucoma. In some cases of papillary block glaucoma, the glaucoma may not resolve because the entrapment of aqueous in several compartments behind the iris. In such cases, more than one iridotomy is required.

The first treatment modality, which is usually the simplest, if the cornea is clear, is peripher‐ al laser iridotomy. It is usually performed with Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG) laser. Topical glycerin may be placed over the cornea before the procedure if it is edematous. After instillation of topical pilocarpine 2% or 4% and topical analgesic (e.g., oxy‐ buprocaine HCl 0.4% or proparacaine HCl 0.5%) eye drop, a spot of 10mJ is placed over the peripheral iris. Two pulses may be used simultaneously. The size of the spot is constant de‐ pending on the instrument (50-70µm). The spot is placed at the periphery of the iris in the superior half to avoid glare, and over a thin part of the iris (usually a crypt) avoiding blood vessels. If bleeding occurs, the cornea is pressed by a contact lens until bleeding ceases. The procedure may be performed with contact lens such as Abraham (+66D), Wise (+103D), CGIor without it. The advantages of a contact lens are additional magnification, focusing the beam, absorbing part of the heat, stabilizing the eye and keeping the eyelids open. Topical apraclonidine (Iopidine®) 0.5%-1.0% or other alpha 2 agonist (e.g., brimonidine tartrate) is administered following the procedure to decrease IOP spikes and corticosteroids such as prednisolone acetate 1% qid are prescribed for a week to decrease intraocular inflammation and risk of synechiae formation. Additional anti-glaucoma medications may be added. This procedure facilitates aqueous flow from the posterior into the anterior chamber and may re‐ sult in deepening of the anterior chamber and lowering the IOP. The major complication is acceleration of cataract. If Nd:YAG laser is unavailable, Argon laser iridotomy may be per‐ formed. The parameters for this procedure depend on the iris pigmentation. For brighter iris, the power is lower than for darker ones. The preparatory stretch burns are of 200-600mW, 0.2-0.6 sec, 200-500 µ m. The penetration burns are of 800-1000mW, 0.2 sec, 50µm. The iridotomy size should be increased to 150-500µm. The position of the Argon iri‐ dotomy in this case is preferably supero-nasal to prevent injury to the macula. Argon laser may increase the intraocular inflammation because it releases pigment due to a different mechanism of action (plasma creation by ionizing in cases of ND:YAG versus coagulation in Argon). The treatment before and after the procedure is identical to Nd:YAG laser iridoto‐ my. Perforation of the iris is confirmed when aqueous mixed with pigment is flowing from the posterior to the anterior chamber through the iridotomy. The lens should be visible through the iridotomy, since positive transillumination is not reliable. When laser iridotomy is not feasible or is impossible to perform, surgical peripheral iridectomy should be per‐ formed. Complications include visual disturbances such as halo and glare, development and progression of cataract, transient corneal burns, temporary increase in IOP, intraocular in‐ flammation and rarely retinal injury, CME and malignant glaucoma.

Argon laser trabeculoplasty has no role in uveitic open-angle glaucoma because of its low success rate. It may increase the intraocular inflammation and alter the angle structure. Some authors found selective (ND:YAG) laser trabeculoplasty to be effective in 20% of the patients, [39] but the follow-up was limited and the effectiveness is expected to decline. Therefore, it is not an ideal solution. The reason is that both procedures do not prevent the obstruction of the open angle by inflammatory products.

#### **7.2. Surgical treatment**

inflammatory (NSAID) such as nepafenac 0.1% (Nevanac®), ketorolac tromethamine 0.5% (Acular® or Tradol®), diclofenac sodium (Voltaren® (0.1%), Solaraze® (3%)) or indometha‐ cin 1% (Indoptic®) may be used. Topical immunosuppressive agent such as cyclosporine A 0.5-2% and systemic immunosuppressive drugs may be alternatives for corticosteroids and NSAID. The dosage of corticosteroids depends on the severity of inflammation and is titrat‐ ed according to the response to treatment. The corticosteroids are gradually tapered accord‐ ing to the response since abrupt discontinuation may cause flare-up. Topical cycloplegic agents such as cyclopentholate HCl 1% (in neonates 0.5%) tid are added to control pain that

originates from the ciliary body and to prevent the formation of posterior synechiae.

new drugs such as Rho kinase inhibitors may replace existing medications.

**7. Laser treatment**

368 Glaucoma - Basic and Clinical Aspects

**7.1. Laser iridotomy**

cases, more than one iridotomy is required.

The preferred anti-glaucoma medications include topical alpha agonists, carbonic anhydrase inhibitors and beta-blockers. Prostaglandins may be added in a quiet eye but should be avoided in an inflamed eye and herpetic keratouveitis because they may exacerbate the in‐ traocular inflammation and cause CME. [33]- [35] Oral or intravenous carbonic anhydrase inhibitors (acetazolamide 500mg) and hyperosmotic agents (oral glycerol 50% or IV manni‐ tol 20% 1gr/kg) should be added if the reduction in IOP is not to the normal range. The effi‐ cacy of prostaglandins and alpha adrenergic agonists may decrease with concurrent use of topical or systemic NSAID. [36], [37] The glaucoma is controlled by medical treatment in 26% of the children and 24% of the adults. [6] In near future, ocular implants containing slow release IOP sparing corticosteroids may improve the visual outcome of patients with macular edema secondary to uveitis without inducing steroid-induced glaucoma. In future,

Laser iridotomy is indicated for all cases of secondary papillary block glaucoma, chronic an‐ gle closure glaucoma and prophylactically when progressive anterior synechiae are being formed. [38] It is performed either to allow aqueous humour access into the anterior cham‐ ber in papillary block glaucoma or increase in the depth of the anterior chamber in chronic angle closure glaucoma. In some cases of papillary block glaucoma, the glaucoma may not resolve because the entrapment of aqueous in several compartments behind the iris. In such

The first treatment modality, which is usually the simplest, if the cornea is clear, is peripher‐ al laser iridotomy. It is usually performed with Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG) laser. Topical glycerin may be placed over the cornea before the procedure if it is edematous. After instillation of topical pilocarpine 2% or 4% and topical analgesic (e.g., oxy‐ buprocaine HCl 0.4% or proparacaine HCl 0.5%) eye drop, a spot of 10mJ is placed over the peripheral iris. Two pulses may be used simultaneously. The size of the spot is constant de‐ pending on the instrument (50-70µm). The spot is placed at the periphery of the iris in the superior half to avoid glare, and over a thin part of the iris (usually a crypt) avoiding blood vessels. If bleeding occurs, the cornea is pressed by a contact lens until bleeding ceases. The

Surgical procedures are reserved for patients who fail to respond to medical treatment. Sur‐ gical intervention is required in 56% of the children and in 35% of the adults with uveitic glaucoma. [6] Any intraocular intervention should be performed on a quiet eye for at least 3 months. Topical corticosteroids or other medications as indicated above should be adminis‐ trated two weeks preoperatively and postoperatively to control the uveitis. Systemic cortico‐ steroids may be added. Any intervention on an inflamed eye may result in exacerbation of the uveitis, failure of the procedure and complications. When increased postoperative intra‐ ocular inflammation is anticipated, enoxaparin (Clexan®) (40mg/500 balanced salt solution (BSS)), a low-weight molecular heparin decreases the intensity of such inflammation in sur‐ gery for uveitic eyes as it does in congenital cataract surgery. [40] Glaucoma surgery may be combined with cataract extraction. The data on the newer procedures in uveitic glaucoma are limited. Detailed description of the newer devices can be found in chapter 19 in this book, chapter 20 in Rumelt S. Ed. Glaucoma – basic and clinical concepts. Rijeka, Croatia: Intech 2011 and chapter 17 in Rumelt S. Ed. Advances in ophthalmology. Rijeka, Croatia: In‐ tech 2012.

it as the procedure of choice in uveitic glaucoma. [52], [53] Two types of drainage implants exist. The first type is with control of the flow (with a "valve" or flow resistance) and in‐ cludes Ahmed (New World Medical, Rancho Cucamonga, CA) and Krupin-Denver (Hood Laboratories, Pembroke, MA) drainage implants. The second type is without pressure con‐ trol (no valve) and includes Molteno single or double plate (IOP, Inc., Costa Mesa, CA, USA, and Molteno OpLimited, Dunedin, New Zealand), Baerveldt (Advanced Medical Optics, Santa Ana, California, USA), Shocket (self-assembled) and Eagle Vision (Eagle Vision, Inc. Memphis, TN, USA) implants. The later require blocking the aqueous flow for a few days externally by temporary suture or internally passing a suture through the lumen of the tube or injecting viscoelastic agent. The implantation may also be performed as a two-stage im‐ plantation, to decrease the risk for postoperative hypotony. Ahmed and Krupin implants should be preferred over the implants without a valve, because the risk for postoperative overflow and hypotony that may result in endothelial-iris and lens touch. This is more prev‐ alent in patients with uveitis than without it because the aqueous production is usually low. Ahmed valve has convenient plate of variable sizes including for pediatric population.

Uveitic Glaucoma

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http://dx.doi.org/10.5772/55708

The success rate of Ahmed implant in uveitic glaucoma at one year is 77-94% and at 4 years 50%. [54]- [56] The success rate of Baeveldt implant at 1 year is 92%. [47] A decrease in cor‐ neal endothelial cell count has been observed with glaucoma drainage devices (Ahmed) in comparison with non-valved implanted eyes. The decrease in endothelium is related to the age of the patient, duration of the uveitis and presence of the implant and corneal-valve

It is expected that this device will have the advantages of trabeculectomy (guarded filtra‐ tion) and other glaucoma drainage device (uniform internal opening) as long as it will not be blocked by inflammatory products. We have found that it is beneficial in secondary glau‐ comas including uveitic glaucoma (in publication). The only exceptions are neovascular glaucoma and iridocorneal endothelial syndrome where it usually fails. No other data are

IStent is a titanium device that is placed into the Schlemm's canal through the anterior chamber. This device may be effective in secondary glaucoma and may decrease the require‐ ment for postoperative hypotensive medications. It has not been proven yet to be effective in

Trabectome is a micro-electrical device that removes the trabecular meshwork and unroof the Schlemm's canal under gonioscopy to decrease the resistance to aqueous outflow. No re‐ sults of this device in uveitic glaucoma are available. It is expected that it will have only a

available on the outcome of ExPress implantation in uveitic glaucoma.

touch. [57]

**9.2. IStent**

uveitic glaucoma.

**9.3. Trabectome**

**9.1. ExPress shunt**

#### **7.3. Trabeculectomy**

As for all secondary glaucomas, uveitic glaucoma that does not respond to medical treat‐ ment should be treated with trabeculectomy and mitomycin C (MMC) or other shunting procedure. [41]-[46] Without MMC, trabeculectomy may fail. Trabeculectomy with MMC is indicated for open and closed angle glaucomas. MMC decreases the risk of scarring of the filtering bleb, which is higher in uveitic glaucoma than in primary glaucomas, because of the increased postoperative inflammation. MMC 0.04% may be applied for 3 min under the scleral flap (or the conjunctiva) avoiding the conjunctival margins. Copious BSS irrigation is performed to remove the free MMC.

The cumulative probability for success of trabeculectomy with MMC or 5-fluorouracil at 1 and 2 years was 78 and 68% respectively. [4] Risk factors for failure include male gender and young age. [47] The use of spacers such as collagen matrix (Ologen®) or other biodegrada‐ ble material may prove to be beneficial as well as injection of subconjunctival bevacizumab 2.5mg/0.1ml.These should be evaluated for uveitic glaucoma.
