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•The guarded filtering procedure (trabeculectomy) has been used to control the IOP in these eyes with poor results. The success rate is somewhat better if an adjunctive antimetabolite such as mitomycin C is used. The risk of filtration failure due to fibrosis is higher, presumably owing to the presence of angiogenic factors in the aqueous.

•Aqueous tube shunts have become the procedure of choice for many glaucoma surgeons, but still have success rates of only approximately 70%, owing to the often poor prognosis of the underlying pathologic process.

4.Laser cyclophotocoagulation. This may be a viable option in eyes with minimal visual potential, as an attempt to control IOP for long-term comfort and to prevent the need for enucleation for pain owing to high IOP. The diode laser is the preferred method of cyclophotocoagulation. Cyclophotocoagulation by cryotherapy is seldom used nowadays because of the risk of phthisis bulb and postoperative pain and inflammation.

MISCELLANEOUS

45.What are the various mechanisms of producing angle closure secondary to ocular inflammation?

•PAS formation from any etiology

•Complete pupillary block (secluded pupil) from posterior synechiae resulting in iris bombé

•Uveal effusion causing anterior rotation of the ciliary body (uncommon)

•Exudative retinal detachment pushing the lens–iris diaphragm forward (rare)

N.B. Intraocular inflammation leads to elevated IOP mostly through open-angle mechanisms: block-

age of the trabecular meshwork by debris or pigment and steroid-induced ocular hypertension.

46.Describe nanophthalmos.

Nanophthalmos is a bilateral condition in which the globes are significantly shorter than normal, with an axial length less than 20 mm (mean 18.8 mm), with a corresponding hyperopia. In addition, the corneal diameter is smaller (mean 10.5 mm versus 12 mm for a normal adult) and the sclera is much thicker (often at least twice as thick) than normal. The unusually thick sclera creates an impediment to uveoscleral outflow that predisposes to choroidal effusions, either spontaneously or after surgery, and angle closure. Angle-closure glaucoma can also occur as a result of anterior-segment crowding without uveal effusions.

47.List one systemic medication that can cause angle closure by producing ciliochoroidal effusions and the principles for management of this type of angle closure.

Topiramate, a sulfa-derived antiepileptic medication whose indications have expanded to include the treatment of migraine headaches and obesity, has been reported to cause idiosyncratic ciliochoroidal effusions with acute onset myopia and angle-closure glaucoma. Thus, a careful and thorough history can be crucial in making the diagnosis. These changes do gradually resolve with discontinuation of the medication. Pupillary block is usually not present and thus laser peripheral iridotomy is not helpful. Miotics will make the problem worse, as they cause anterior movement of the lens–iris diaphragm. The treatment includes topical and systemic aqueous suppressants, systemic hyperosmotics if necessary for IOP control, steroids, and cycloplegics to help pull the lens–iris diaphragm posteriorly.

WEBSITES

1.The Glaucoma Foundation: www.glaucomafoundation.org

{link accessed successfully by Maria on 9.18}

2.Glaucoma Research Foundation: www.glaucoma.org

{link accessed successfully by Maria on 9.18}

3.www.gonioscopy.org

{link accessed successfully by Maria on 9.18}

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1.A 72-year-old man presents for a routine exam. He states that vision in the left eye is getting bad. On exam, he has vision of 20/30 in the right and counts fingers at 3 feet in the left. The intraocular pressure in the right eye is 25 mmHg, in the left eye, 42 mmHg. The optic nerve appears somewhat cupped on the right, severely so on the left. Visual fields reveal a significant nasal step in the right eye and a temporal island on the left. He does not have pseudoexfoliation syndrome or a Krukenberg spindle in either eye. His angles are deep. What do you suspect?

A history of trauma. The patient had been a boxer, and he was often hit in his eyes. Angle-recession glaucoma can be asymptomatic until many years later when visual loss occurs. On gonioscopy, the angle recession is determined by torn iris processes and posteriorly recessed iris, revealing a widened ciliary body band. Comparison with the other eye may help to identify this condition. Any patient with traumatic iritis or hyphema needs to be warned of this complication, which may occur many years later. Treatment is the same as with open-angle glaucoma except that miotic agents are ineffective and may even increase the intraocular pressure. Argon laser trabeculoplasty (ALT) is rarely effective.

2.What should you look for to make a diagnosis of pseudoexfoliation glaucoma?

Fibrillar, “dandruff-like” material is deposited on the anterior lens capsule in a characteristic bull’s eye pattern, most easily seen after pupillary dilation. This material is also seen clinically in the angle and on the iris. Gonioscopy reveals a heavily pigmented trabecular meshwork and a Sampaolesi’s line, which is pigment deposited anterior to the Schwalbe’s line (Fig. 17-1).

Pseudoexfoliation syndrome is thought to be part of generalized basement membrane disorder, because it can be found histologically in other parts of the body. It may be unilateral or bilateral with

Figure 17-1.  The Sampaolesi’s line is a scalloped band of pigmentation anterior to the Schwalbe’s line. (From Alward WLM: Color Atlas of Gonioscopy. St. Louis, Mosby, 1994.)

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7.What does a Krukenberg spindle look like? What does it mean?

A Krukenberg spindle is a vertical pigment band on the corneal endothelium (Fig. 17-2). It is typically found in patients with pigmentary dispersion syndrome. The iris is often bowed posteriorly and rubs against the lens zonules. This process causes midperipheral spokelike iris transillumination defects. Gonioscopy reveals a densely pigmented trabecular meshwork for 360 degrees. The patient is often asymptomatic but may notice blurred vision, eye pain, and halos around lights after exercise or pupillary dilation. Pigmentary dispersion syndrome is more common in young adults and white, myopic males. It is usually bilateral.

8.How is pigmentary dispersion treated?

If no optic disc damage is noted and the visual fields are normal, the patient may be observed. Treatment for intraocular pressure over 28 mmHg is usually indicated, although this point is controversial. Once damage is noted, miotics may be the first line of therapy because they minimize contact between the zonules and the iris. However, miotics also cause myopic fluctuation and may not be practical in young patients, especially in myopes with lattice degeneration because of their increased risk of retinal detachment. Laser peripheral iridectomy has been recommended; it treats the posterior bowing of the iris and may theoretically cure the disorder. The pressures may still be elevated until the residual pigment in the trabecular meshwork is cleared. This treatment is controversial and seems to have fallen out of favor. Patients also respond well to ALT or SLT because of the increased pigment of the trabecular meshwork.

9.A 95-year-old woman presents with a markedly red, painful right eye of 2 days’ duration. Her vision is hand motions at 1 foot and 20/400 in the right and left eye, respectively. Exam of the right eye reveals a steamy cornea with a pressure of 60 mmHg and no view of the anterior chamber. The left eye has a brunescent cataract but appears to be deep and quiet with a pressure of 18 mmHg. With topical glycerin, the cornea clears in the right eye to reveal iridescent particles floating in the anterior chamber with a morgagnian cataract. Gonioscopy reveals bilateral open angles. No view is obtained of either posterior chamber. What do you do now?

The patient denies a history of uveitis. A B-scan of both eyes reveals only significant cataract without retinal detachment or intraocular tumor. The leakage of lens material through an intact lens capsule is obstructing the trabecular meshwork. If the diagnosis is in question, paracentesis may be done

to examine the anterior chamber reaction microscopically. Macrophages are filled with lens cortical material (phacolytic glaucoma). Typically, the lens is hypermature, as in this patient. The intraocular pressure must be reduced and the inflammation controlled before surgical therapy is attempted. A steroid such as prednisolone acetate 1% every hour, a cycloplegic such as scopolamine 0.25% three times/day, and antiglaucoma medications are started immediately. Cataract extraction is performed in the next day or two once the eye is less inflamed.

10.A 64-year-old woman who had cataract surgery in the left eye 1 week ago presents to the emergency department complaining that the eye is red and painful with decreasing vision. What is your concern?

First, you must think of endophthalmitis. Any patient presenting after surgery with a red, painful eye with decreased vision must be presumed to have endophthalmitis until it is ruled out. The exam

Figure 17-2.  A Krukenberg spindle (arrow) is made of pigment deposited on the endothelium in pigmentary dispersion syndrome. (From Alward WLM: Color Atlas of Gonioscopy. St. Louis, Mosby, 1994.)

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reveals vision of hand motions at 2 feet, a severely injected eye with corneal edema, 4+ cell and flare, and an intraocular pressure of 47 mmHg. The anterior chamber is filled with lens cortical material, and a rupture in the posterior capsule is seen. A large chunk of nuclear material is in the vitreous. The optic nerve is mildly cupped.

Because the lens material is seen in the anterior chamber, treatment with steroids and antiglaucoma medications is appropriate, along with close observation. The diagnosis is most likely lens-particle glaucoma. The patient is started on prednisolone acetate 1% every 2 hours, scopolamine 0.25% three times/day, latanoprost once daily, a β-blocker twice daily, apraclonidine twice daily,

and acetazolamide sequels twice daily. In addition, because her pressure is so high, mannitol is given. When the pressure improves to 25 mmHg, she is sent home. The next day, she counts fingers at 5 feet, her intraocular inflammation is subsiding, and the pressure is 23 mmHg. Once her eye is less inflamed and the pressure well controlled, she is scheduled for removal of the remaining lens material. If the retained lens material is minimal, patients sometimes can be maintained on medical therapy until the eye clears without surgery.

11.What other type of open-angle glaucoma can be caused by the lens?

Phacoanaphylactic glaucoma, which occurs after penetrating trauma or surgery. The patient is sensitized to the lens protein during a latent period and develops a granulomatous uveitis. This feature distinguishes it from lens-particle glaucoma. Patients are treated medically and may need surgery to remove the lens if they do not respond adequately.

12.What is Posner-Schlossman syndrome? Who gets it?

Patients are young to middle-aged. They notice unilateral attacks of mild pain, decreased vision, and halos around lights. Episodes tend to recur. Also known as glaucomatocyclitic crisis, this disorder is idiopathic. On exam, intraocular pressure is high, usually between 40 and 60 mmHg. The angle is open on gonioscopy without synechiae, and the eye is minimally injected. Anterior chamber reaction is minimal. The corneal epithelium may be edematous because of the acute rise in pressure. A few fine keratic precipitates may be present on the corneal endothelium, often inferiorly. Treatment includes steroids and antiglaucoma medications to reduce aqueous production. A cycloplegic agent is necessary only if the patient is symptomatic. The attacks usually resolve in a few hours to a few weeks. No therapy is needed between attacks. However, the risk of chronic open-angle glaucoma is increased in both eyes.

13.What is the classic triad of Fuchs’ heterochromic iridocyclitis?

This consists of heterochromia, cataract, and low-grade iritis. The iritis is mild and does not cause synechiae. Characteristic stellate, colorless keratic precipitates are seen over the inferior endothelium. Fine new vessels may be seen in the angle but do not cause closure. The glaucoma is difficult to control and often does not correspond to the degree of inflammation. Steroids are not often helpful.

14.A patient reports for postoperative check-up 1 day after cataract surgery. The pressure in the operated eye is 40 mmHg, and the patient complains of nausea. What is the most likely cause?

Retained viscoelastic from surgery. The pressure usually increases 6 or 7 hours after surgery and normalizes within 24 to 48 hours, depending on the type of viscoelastic. Most eyes tolerate short-term pressures up to 30 mmHg; of course, tolerance depends on preexisting optic nerve status. Medical treatment and paracentesis to remove the viscoelastic are indicated to decrease pressure quickly and relieve nausea. Paracentesis is somewhat controversial because of the small increased risk of endophthalmitis.

15.What else can cause postoperative glaucoma?

Hyphema, pigment dispersion, generalized inflammation, aphakic or pseudophakic pupillary block,

malignant glaucoma (aqueous misdirection syndrome), and steroid-response glaucoma. In patients who have undergone an intracapsular cataract extraction, α-chymotrypsin is injected into the anterior chamber to dissolve the zonules. The zonular debris may block the trabecular meshwork postoperatively. Epithelial ingrowth may occur many months to years after surgery or trauma and block outflow.

16.A patient had cataract surgery 1 year ago but continues to have episodes of anterior chamber cell and flare with increased intraocular pressure. Some of the cells are red blood cells. What is the diagnosis?

The diagnosis is uveitis–glaucoma–hyphema syndrome. The cells may layer out to produce a hyphema, usually as a result of irritation from an anterior chamber intraocular lens, although a

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posterior chamber lens may be involved. Gonioscopy may reveal where the irritation is occurring, such as from a lens in the sulcus or a haptic causing iris chafing. Treatment consists of atropine, topical steroids, and antiglaucoma medications until the pressure is reduced. Argon laser of the bleeding site, if it can be identified, may be curative. However, exchange or removal of the intraocular lens is often necessary.

17.How can raised episcleral venous pressure cause glaucoma?

Aqueous drains from the anterior chamber through the trabecular meshwork, Schlemm’s canal, and intrascleral channels to the episcleral and conjunctival veins. Normal drainage depends on an episcleral venous pressure that is lower than the pressure of the eye. Usually, it ranges from 8 to 12

mmHg. However, if it is higher than intraocular pressure, drainage does not occur. Blood will be seen in the Schlemm’s canal on gonioscopy. Drugs that reduce aqueous humor formation are obviously the most effective medical treatment.

KEY POINTS: CAUSES OF RAISED EPISCLERAL VENOUS PRESSURE

1. Thyroid ophthalmopathy.

2. Carotid and dural fistulas.

3. Superior vena cava syndrome.

4.Retrobulbar tumors.

5.Orbital varices.

6.Sturge-Weber syndrome.

18.A patient with long-standing diabetes has had recurrent vitreous hemorrhage. While you are observing him, waiting for the condition to clear, intraocular pressure increases to 35 mmHg. What should you suspect?

When intraocular hemorrhages clear, hemolytic or ghost-cell glaucoma may develop. Hemolytic glaucoma occurs because macrophages full of hemoglobin block the trabecular meshwork. Reddish cells can be seen in the anterior chamber. In ghost-cell glaucoma, degenerating red blood cells block the aqueous outflow. Khaki cells in the anterior chamber may layer out to form a pseudohypopyon. Both conditions can be treated medically until the hemorrhage clears. However, because the intraocular pressure may become markedly raised, washout of the anterior chamber and/or vitrectomy often becomes necessary. In addition, the patient may be developing neovascular glaucoma; thus it is important to check the angles for new vessels and angle narrowing.

19.What other conditions may cause open-angle glaucoma?

1.Intraocular tumor may cause secondary open-angle glaucoma by invasion of the chamber angle or blockage of the trabecular meshwork by tumor debris.

2.Siderosis or chalcosis from a retained metallic foreign body.

3.Chemical injuries from acid or alkali can shrink the scleral collagen or cause direct damage to the trabecular meshwork.

4.Posterior polymorphous dystrophy is a bilateral and autosomal dominant disease. Vesicles are seen at the Descemet’s membrane. Corneal edema occurs in severe cases. Iridocorneal adhesions may occur. Glaucoma is associated in 15% of cases.

5.Iridocorneal endothelial syndrome

20.What is iridocorneal endothelial syndrome?

It is a spectrum of three entities that overlap considerably:

•Essential iris atrophy: Iris thinning leads to iris holes and pupillary distortion

•Chandler’s syndrome: Mild iris thinning and distortion with hammered metal appearance of corneal endothelium

•Cogan-Reese syndrome: Pigmented nodules on the iris surface with variable iris atrophy.

Such patients are generally asymptomatic, middle-aged adults. Usually findings are unilateral with increased intraocular pressure and corneal edema. No treatment is necessary unless corneal edema and glaucoma are present.