Ординатура / Офтальмология / Английские материалы / Ocular Pathology_6th edition_Yanoff, Sassani_2009

c.Endothelialization of the anterior-chamber angle, often extending over the anterior surface of the iris, and formation of new Descemet’s membrane are characteristic components.

Iris nodules may appear late in the course of the disease. At first they appear small and yellow, but then increase in number and become dark brown.

D.Essential iris atrophy (Fig. 16.14)

1.Essential iris atrophy is usually unilateral, is found most often in women, and is of unknown cause.

2.The onset is usually in the third decade.

3.Corneal edema often develops when IOP is slightly elevated or even normal.

The corneal endothelium shows a fine, hammeredsilver appearance, similar to cornea guttata but less coarse.

4.The initial event is the formation of a peripheral anterior synechia distorting the pupil to that side.

a.The pupil becomes more distorted, sometimes with the development of an ectropion uveae.

b.Through-and-through holes develop in the iris, usually opposite to the distorted pupil.

The holes seem to be caused by mechanical traction, related to sector corneal endothelial iris overgrowth.

5.Peripheral anterior synechiae increase circumferentially, and an intractable glaucoma develops.

Corneal endothelial overgrowth is a feature common to all three variants included in the ICE syndrome.

VI. Iridoschisis (Fig. 16.15)

A.The condition starts mainly in the seventh decade of life and is usually bilateral; the sexes are equally a ected.

B.The pupil is not displaced and remains reactive.

C.The anterior iris stromal layers separate widely from the deeper layers, resembling spaghetti.

1.The lower half of the iris is most frequently involved.

2.Initially,the loosened stromal fibers remain attached centrally and peripherally so that the delicate middle part of the fibers bows forward into the anterior chamber. Ultimately, the fibers break, and the free ends float in the aqueous.

D.Glaucoma develops in approximately 50% of a ected eyes; it begins as peripheral anterior synechiae develop.

E.Cause

1.Most cases seem to be a peculiar type of aging change.

2.It may follow trauma.

3.Rarely, it may occur with POAG.

VII. Anterior uveitis (see Figs 3.11 and 3.12)—Anterior uveitis from any cause [e.g., trauma, infection, “allergy,” sympathetic uveitis (phacoanaphylactic endophthalmitis)] may result in posterior synechiae, iris bombé, and, finally, peripheral anterior synechiae.

VIII. Retinopathy of prematurity

A.The retrolental mass of neovascular tissue pushes the lens forward and causes “crowding” of the anteriorchamber angle.

B. Closed-angle glaucoma may result, sometimes years after the initial damage.

IX. Spherophakia (Weill–Marchesani syndrome; see p. 387 in

Chapter 10)

X.Persistent hyperplastic primary vitreous (see p. 747 in

Chapter 18)

A.Repeated hemorrhages result in organization and iridocorneal synechiae.

B.Less often, swelling of the lens or iris bombé can produce a closed angle.

XI. Epithelialization of anterior-chamber angle (see p. 119 in Chapter 5)

XII. Endothelialization of anterior-chamber angle (see Fig. 5.34).

A.Endothelialization of the anterior-chamber angle (or pseudoangle in the presence of peripheral anterior synechiae) is seen histologically in 20% of enucleated eyes.

B.Most of the eyes with endothelialization have peripheral anterior synechiae; a little less than half of the eyes are associated with neovascularization of iris.

C.Histologically, the endothelial cells possess junctional complexes, apical villi, prominent basement membranes, and myoblastic di erentiation.

XIII. Neovascularization of anterior surface of the iris (clinically termed rubeosis iridis; see Figs 9.13, 9.14, and 15.5)

The many causes include diabetes mellitus, central retinal vein or artery occlusion, branch retinal artery occlusion, diffuse retinal vascular disease, carotid artery ischemia, retinoblastoma, malignant melanoma of uvea (Table 16.2), long-standing retinal detachment, any chronic retinal disease, penetrating or contusive ocular injuries, metastatic tumors to the retina and vitreous including cutaneous melanoma, and Fuchs’ heterochromic iridocyclitis (see p. 65 in Chapter 3).

XIV. Cysts of iris and anterior ciliary body (see Figs 9.9 and

9.10)

A.Multiple cysts of the iris and ciliary epithelium can cause both secondary acute and chronic closed-angle glaucoma.

1.Congenital cysts of the iris are extremely rare but may cause secondary glaucoma when they enlarge, and can even be confused with iris melanoma.

2.Primary angle closure glaucoma is uncommon in younger individuals, such as teenagers. Therefore, such individuals who present with angle closure should be evaluated to exclude secondary causes of angle closure such as ciliary body cysts.

The cysts may be idiopathic or may be associated with late syphilitic interstitial keratitis. Another cause of glaucoma in late syphilitic interstitial keratitis is secondary chronic angle closure due to peripheral anterior synechiae.

B. Histologically, a proliferation of the posterior layer of the iris pigment epithelium or of the inner layer of ciliary epithelium lines the cyst (see pp. 339–341 in

Chapter 9).

XV. Juvenile xanthogranuloma (see p. 343 in Chapter 9)

XVI. Secondary to uveal malignant melanoma (Figs 16.16 to

16.18)

A.Posterior synechiae and iris bombé (see Fig. 16.16)

1.A large posterior malignant melanoma and a total neural retinal detachment may combine to displace the iris lens diaphragm anteriorly, resulting in posterior synechiae and iris bombé followed by secondary peripheral anterior synechiae.

2.Similar changes may occur with a large posterior metastatic neoplasm.

B.Neovascularization of iris (see Fig. 16.17)

1.Neovascularization of the iris may occur with a large posterior choroidal malignant melanoma.

2.The neovascularization causes peripheral anterior synechiae.

3.Similar changes may occur with a large posterior metastatic neoplasm.

C.Di use iris malignant melanoma (see Fig. 16.18)

1.A di use iris malignant melanoma, or even a di use iris nevus, may induce peripheral anterior synechiae,

although di use melanomas do not usually present with such changes.

2.The condition may simulate the ICE syndrome.

Rarely, an aggressive iris nevus can involve the angle, cause synechiae, and result in secondary angle closure glaucoma.

XVII.Immune recovery resulting from highly active antiretroviral therapy (HAART) has been associated with severe vitritis resulting in acute angle closure secondary to posterior synechias in a patient with inactive AIDS and inactive cytomegalovirus retinitis.

XVIII. Dense vitreous hemorrhage can result in angle closure, presumably from anterior displacement of the iris lens diaphragm.

XIX. Snake bite is an unusual cause of bilateral angle-closure glaucoma.

B

Fig. 16.15 Iridoschisis. A, The iris is in disarray, with long rolled strips from the 3 o’clock to the 6 o’clock position. B, The gross specimen from another eye shows separation and breakage of the collagenous columns of the iris stroma. C, Histologic section of the eye shown in

B demonstrates epithelial blebs (bullous corneal edema) and separation of the iris stroma into elongated lamellae. (A, Courtesy of Prof. GOH Naumann.)

XX.Autosomal vitreoretinochoroidopathy can be associated with angle closure secondary to microcornea and shallow anterior chamber without microphthalmia.

Secondary Open-Angle Glaucoma

I.Secondary to cells or debris in angle

A.Hyphema (see p. 135 in Chapter 5)

B.Uveitis

1.Cyclitis (or iridocyclitis) may lead to excessive cellular production that obstructs the open angle.

Anterior uveitis usually causes a decrease in aqueous inflow so that glaucoma rarely ensues. Glaucoma is also less likely if the cyclitis is segmental rather than circumferential. Glaucoma is most unlikely with a posterior cyclitis or pars planitis. Intractable glaucoma may complicate herpes simplex ocular infection even in the absence of obvious keratitis. Such infection can be confirmed by polymerase chain reaction analysis of aqueous humor.

2.Glaucomatocyclitic crisis (Posner–Schlossman syndrome)

a.The condition mainly occurs as a unilateral acute rise in IOP in people in their third through fifth decades; it may recur.

Although the cause is unknown, an abnormal instability of the ciliary vascular system may be related to the development of the acute glaucoma.

b.Epithelial edema and one or more keratic precipitates (tiny and fine at first, but may become mutton-fat) are seen clinically.

Indirect evidence suggests that the herpes simplex virus may play a role in the origin of Posner–Schloss- man syndrome.

c.Little or no reaction occurs in the aqueous humor, and the angle usually appears normal.

d.The disease is self-limited and subsides in 1 to

3 weeks.

e.The histology is unknown.

Glaucomatocyclitic crisis appears to have a predilection for patients who have POAG or in whom it will develop.

3.In oculodermal melanocytosis, in the involved eye, glaucoma may result from a low-grade chronic anterior uveitis of unknown cause.

C.Phacolytic glaucoma (see p. 384 in Chapter 10)

D.Nondenatured lens material-induced glaucoma usually follows a very recent traumatic rupture of the lens.

1.If glaucoma develops after needling of a soft cataract, it occurs within the first week.

2.After penetrating ocular injury

3.The glaucoma is caused by occlusion of the open anterior-chamber angle by the swollen lens material, and is not related to phagocytic action.

The ruptured lens may not release its material, but may swell and result in pupillary block and a secondary acute or chronic closed-angle glaucoma.

E.Hemolytic (ghost-cell) glaucoma (Figs 16.19 and 16.20)

1.Hemolytic (ghost cell) glaucoma presents as an acute open-angle glaucoma.

2.The glaucoma results as a complication of longstanding vitreous or, rarely, anterior-chamber hemorrhage from any cause.

Glaucoma may be caused by macrophages and red blood cell (RBC) debris, especially hemoglobin aggregates, or by hemolyzed RBCs (ghost cells). Both RBC debris and ghost cells result from hemolysis; therefore, hemolytic glaucoma is a more accurate term than ghost cell glaucoma. Neither fresh RBCs nor ghost cells seem able to pass from the vitreous compartment through an intact anterior hyaloid face into the aqueous compartment; a rent or passageway is necessary.

3.Histologically, the anterior-chamber angle is obstructed by debris, hemoglobin, ghost cells, and macrophages filled mainly with hemoglobin but also containing some hemosiderin.

F.Pigment dispersion syndrome (pigmentary “glaucoma”;

Figs 16.21 and 16.22)

1.The pigment dispersion syndrome is found most often in young, myopic, adult white men.

a.Pigment dispersion may result from iris chafing secondary on foreign material such as an intraocular lens.

A

B

Fig. 16.19 Hemolytic (ghost-cell) glaucoma. A, Macroscopic appearance of fresh blood in subvitreal area (dark red) and old blood in vitreous (yellow-red). B, Histologic section shows intact erythrocytes (toward lower left). Hemolysis of the erythrocytes releases the hemoglobin particles and leaves empty shells (“ghost cells”) behind.

The insertion of the iris into the ciliary body is more posterior in pigment dispersion syndrome than in control eyes. A low prevalence of pigment dispersion syndrome and pigmentary glaucoma occurs in blacks, Hispanics, and Asians. In black patients, pigmentary glaucoma tends to develop in an older age group (average, 73 years), mainly in hyperopes and women, shows no iris transillumination, and occurs in irises that have a relatively flat connection to the anterior face of the ciliary body.

2.Depigmentation of the iris epithelium, especially peripherally, results in circumferential foci of

increased iris transillumination where the peripheral third of the iris meets the middle third.

The eye on the side of greatest increased iris transillumination may contain a larger pupil than the other eye (anisocoria). By slit-lamp biomicroscopy, a band of increased granular iris pigmentation can be seen overlying the ring of increased retroillumination (best seen in blue irises but also seen fairly easily in brown). The band is presumably caused by the many pigment-filled macrophages in this region of stroma. In predisposed eyes, because of a basic abnormality of the iris pigment epithelium, an important factor in the loss of posterior iris pigment may be the rubbing between anterior packets of zonules and peripheral iris.

3.Iridodonesis may be present.

4.Krukenberg’s spindle consists of a vertical band of melanin pigment phagocytosed by the central and inferior corneal endothelium, most often bilateral.

Pigment may be released into the aqueous compartment after pupillary dilatation or after physical exercise. When a Krukenberg’s spindle is present unilaterally, ocular trauma may be the cause.

5.The pigment is deposited on the iris surface, lens, zonules, and in the trabecular meshwork.

The disease seems to ameliorate with increasing age in some patients. In these patients, the corneal and trabecular meshwork pigmentation decreases. The picture resembles that of pseudoexfoliation of the lens. Rarely, the pigment dispersion syndrome can coexist with the pseudoexfoliation syndrome.

6.Incidence of neural retinal detachments is increased in patients who have pigment dispersion syndrome, and there is an increased incidence of retinal lattice degeneration.

Glaucoma seems to be present in approximately 10% of cases. Perhaps the relationship of the iris pigment epithelial defect to the glaucoma is a matter of two independent gene loci that are very close together on the same chromosome and tend to be inherited together, but not necessarily so. Furthermore, patients with pigment dispersion syndrome and glaucoma are the same age (approximately 49 years) as patients with the syndrome but without glaucoma. If glaucoma resulted from the dispersion of pigment, patients with glaucoma should have a higher average age than patients without glaucoma. The number of aqueous melanin granules (measured with the laser-flare cell meter) correlates with increased IOP.

7.Compared with normal eyes, pigment dispersion syndrome eyes have a larger iris, a mid peripheral posterior iris concavity that increases with accommodation, a more posterior iris insertion, increased

E

iridolenticular contact that is reversed by inhibition of blinking, possibly an inherent weakness of iris pigment epithelium.

a.The most likely cause of the aforementioned constellation of findings is a gene a ecting some aspect of the development of the middle third of the eye.

8.Histologically, the posterior layer of iris pigment epithelium, mainly at the junction of middle and peripheral thirds of the iris, atrophies in foci that

correspond to the clinically observed peripheral foci of increased iris transillumination.

a.The dilator muscle may be dysplastic, present in excessive amounts, atrophic, or absent.

b.The adjacent iris stroma contains pigment-filled macrophages.

c.Neuroepithelial melanin granules are widely distributed in the endothelium of both the posterior cornea (Krukenberg’s spindle) and the trabecular meshwork.

9.Mutations in the genes encoding for melanosomal proteins can cause pigmentary glaucoma and iris stromal atrophy in a DBA/2J mouse model. These findings suggest that pigment production and mutant melanosomal protein genes may contribute to human pigmentary glaucoma.

10.Familial occurrence of pigment dispersion syndrome has been reported.

11.The cause is uncertain, but the pigmentary changes may be coincidental to the glaucoma instead of its cause.

G.Pseudoexfoliation syndrome (see pp. 368–373 in Chapter 10)

H.Secondary to uveal malignant melanomas (Figs 16.23 to 16.25; see Table 16.2)

1.Seeded malignant melanoma cells (see Fig. 16.23) may block the anterior-chamber angle.

Similar seeding can occur with metastatic neoplastic cells or juvenile xanthogranuloma cells. Rarely, an aggressive

nevus can infiltrate an open angle, resulting in secondary open-angle glaucoma.

2.A ring malignant melanoma (see Fig. 16.24) may directly invade the anterior-chamber angle structures and block the open angle.Therefore, glaucoma my be the presenting finding.

A ring melanoma arises from the root of the iris and anterior ciliary body for 360° and should not be confused with a segmental iris or ciliary body melanoma that may seed the anterior-chamber angle for 360°.

3.Melanomalytic glaucoma (see Fig. 16.25)

a.Necrosis (partial or complete) of a malignant melanoma (or a melanocytoma), usually of the ciliary body, causes the liberation of melanin pigment.