Ординатура / Офтальмология / Английские материалы / The Glaucomas Volume 1 Pediatric Glaucomas_Sampaolesi, Zarate_2009

The lower part represents the iris and pupil and the affected part is marked. In the upper part, a schema of the malformation of the chamber angle from the Schwalbe line backward (Fig. 20.14).

In the scleral wall of the chamber angle remnants of dark pigment can be seen (Fig. 20.15) or a tissue that is different from the iris tissue, which fills the chamber angle, or ramified pathological mesodermal remnants (Fig. 20.16), or a prominent Schwalbe line, etc.,

but these variations are always limited to the lower nasal zone. This anomaly often appears together with a change in the iris pigmentation in that area, which sometimes reaches the pupil (Fig. 20.17). There are also eccentricities in the frill of the iris.

One feature of this anomaly is the presence of mesodermal pathological remnants (mesodermal tissue) in the lateral parts of the iris depression (Figs. 20.18, 20.19).

Fig. 20.15 Schema showing the lower nasal anomaly of the chamber angle with remnants of dark pigment at the level of Schwalbe’s line

Fig. 20.16 In the zone of the lower nasal anomaly, ramified iris processes and greatly thickened Schwalbe line

Fig. 20.17 Inferior nasal coloboma of the iris shaped like a white triangle

Clinical history No. 6 is a 42-year-old man diagnosed with late congenital glaucoma, with lower nasal malformation and coloboma of the iris mesenchymal layers at 6 o’ clock. He had been treated for the previous 2 years since the hypertension had been discovered accidentally during a routine check-up for refraction. The results were as follows:

Apparently, this malformation is new in the literature. However, Busacca called our attention to work published by Arnold (1911) [11] and Streiff (1915) [12], which are closely related to our findings. Arnold’s paper shows iris pigmentation anomalies at 6 o’ clock and partial coloboma of the anterior mesodermal layer

of the iris in the same way as these were described by Fuchs. Arnold says that these alterations in the iris surface run in families and are hereditary. They occur with alterations to the pigmentation and show varying degrees of insufficient development that may lead to a real anomaly.

In Fig. 20.21 in Streiff ’s paper shows the lower nasal positioning, the eccentricity of the collarette, and the greater depth of the anterior chamber at this point.

In Fig. 15.50 of his book, Vogt [13] also describes a case of hypoplasia of the superficial mesodermal layer of the iris in the lower nasal quadrant and relates it to an optic vesicle fissure closure defect. At the end of his description of this figure, he says that the patient suffered from simple glaucoma and had optic disc excavation. This last remark in the clinical history is highly suggestive.

It should be remembered that in all these cases of late congenital glaucoma, heredity is highly dominant and it is necessary to examine all the members of the family.

Clinical history No. 7 involves a 17-year-old female whom we followed up from 2002 to 2008, diagnosing late congenital glaucoma, goniodysgenesis 360° (Figs. 20.22, 20.23, 20.24, 20.25).

This case shows that at 17 years of age glaucoma with high intraocular pressures, which is not regulated to normal target values with maximum medical treatment, the visual field defects are stage II and the optic nerve phase III in both eyes: surgery had to be done. The decision was not easy to make, but 6 years later, with no medical treatment, the patient’s visual field improved, the optic nerve defect had not progressed, and the visual acuity was exactly the same as at the beginning.

Pigmentary Glaucoma

In the first edition of Glaucoma, Sampaolesi 1974, we presented statistics of 27 cases of pigmentary glaucoma. In the second edition (Sampaolesi 1994) there were 107, and now in this book the number of patients has reached 180, with 5–36 years of follow-up. In most of the cases, we found anomalies of the chamber angle (goniodysgenesis).

The first clinical description of this condition was published in 1949 by Sugar and Barbour [14], and the association between pigmentary glaucoma and congenital glaucoma was described for the first time in 1957 by Malbrán [15]. Etienne [16], Etienne and Pommier [17], Weekers and Watillon [18], Di Tizio and Lepri [19], Nordmann [20], Jerndal et al. [4], Heinzen and Lueder [21] and Shaffer and Weiss [22] share this opinion.

Literature Review

We believe it is very useful to carefully review the literature relating to pigmentary glaucoma and its clinical manifestations.

Mauksch (1925) [23] refers to an observation made in 21-year-old twin brothers: “both have Krukenberg’s spindle and an extraordinary disintegration of the pigment of the iris epithelial layer. The pigment is also deposited on the posterior face of the lens, at the bottom of the bag between the hyaloid membrane and the crystalloids. The irregular borders seen in this ring are probably produced by the insertion of the more posterior zonular fibres.”

In a paper on the study of the Krukenberg’s spindle, Cavara [24] describes several cases in which there is great pigment dispersion originated by the atrophy of the iris. He says that this, like Koby’s work, supports the idea of the pigment line of the periphery of the lens as being acquired and relates it with the hemorrhages of the posterior chamber that are in the same place as the pigment.

Koby [25] describes the case of a 46-year-old woman and her daughter, 22, who have a pigment ring in the posterior face of the lens and also pigment at the arciform boundary. Toward the edge of the lens, the granulations separate from its posterior face to occupy the surface of a transparent substrate in the vitreous body. He describes the following kinds of pigment dispersion in the posterior face of the lens: disseminated, in bands, perihyaloid, inferior, and circular.

Focosy [26], in a paper titled “On the pigment deposits in the posterior crystalloid,” describes the intense pigment dispersion that occurs in these cases and

remembers that in the exfoliative syndrome, as Baumgart described it, there is also great pigment dispersion, and mentions Streiff ’s observation on similar cases, with great aplasia of the iris pigment layer, and Collebati’s case with subluxation of the lens and coloboma of the iris. To my knowledge, this is the first reference to pigment dispersion occurring in exfoliative syndrome, made describing the pigment deposits in the posterior capsule of the lens that are seen in pigmentary glaucoma. As we know, Sugar associated this ring in the posterior capsule of the lens with the condition of pigmentary glaucoma after its discovery. Since then, numerous authors have made the mistake of associating pigmentary glaucoma with exfoliative syndrome but these are actually two completely different disorders, clearly distinct, with their own characteristics, even though they may coincide in the same patient.

Focosy concludes, “Even though the cases of Koby (mother and daughter) and of Mauksch (twins) might suggest that it is a congenital lesion, in fact, my cases, like those of Cavara and Bietti, show that it is an acquired alteration, for two reasons: (1) Because of the great atrophy that is always seen in the pigment layer, (2) because in the cases which I have been able to follow up for a long time, the pigmentation steadily increases.”

Bietti (1934) [27] gives us the most accurate description of this sign: “The pigment accumulates in the capsulohyaloid angle, i.e., in the place where the anterior surface of the vitreous body joins the posterior capsule of the lens. At this point a triangular shaped blind bottom forms. This ring is almost always bilateral, although at times it may be unilateral as in Koby’s case and in one of mine. There are granules of pigment that can sometimes also be present in the vitreous body. This ring is due to the disintegration of the pigment layer of the iris and the pigment collects at the height of Wieger’s capsulohyaloid ligament in the capsulohyaloid angle. This pigment is carried by the flow of the aqueous humor through the zonular fibres to the retrolental space that Reslob described. This ring is an acquired manifestation.”

In her book on congenital defects of the eye, Mann [28] says, “In the 100 mm embryo, the vertex of the ciliary processes is found in contact with the periphery of the lens; in some animals this continues throughout life, and in birds the ciliary processes depress the lens. This contact of the ciliary processes with the lens would leave pigmentation on the posterior face.”

Zentmayer (1938) [29] was the first writer in the United States to describe the association of the Krukenberg spindle with the pigment ring in the posterior face of the lens. He presents two drawings which illustrate zonular fibers with pigment in the lower part, and

he thinks that this arrives there carried by the circulation of the aqueous humor.

Evans et al. [30] describe 202 cases of Krukenberg spindle in the United States, of which 14 present the pigment ring in the posterior face of the lens. They deduce from their study that it is an acquired malformation.

Cameron (1941) [31] states that the transillumination of the iris shows a well-advanced atrophy and that the ring of the posterior face of the lens is formed by rectangular masses of pigment.

Bellows [32] considers that the ring is formed as a consequence of depigmentation, resulting from degenerative changes in the iris and mentions Mann’s study.

As for genetic differences, Becker et al. [33] conclude that pigmentary glaucoma in general is differentiated from open-angle glaucoma by a study with the antigen HLA-7, HLAB13, and HLAB12.

In examining the behavior of the pupil, Kaiser-Kup- fer [34] divide the pigmentary syndromes into three groups: (1) pigmentary syndrome without glaucoma,

(2) pigmentary syndrome with ocular hypertension, and (3) pigmentary syndrome with ocular hypertension and defects of the visual field. This author studied age, sex, iris, gonioscopy, tonography, color of the iris, transillumination, refraction, and pupilography, based on the pathological anatomy of the iris that showed hypertrophy of the dilator muscle. Using the pupilography with infrared rays, he studied the behavior of the pupil and found alterations correlating with the pathological anatomy.

In pigmentary syndrome and pigmentary glaucoma, Farrar et al. [35] analyzed 93 patients with pigmentary glaucoma and 18 with pigmentary syndrome, 75% of whom were men. The pigmentary glaucomas had greater myopia and a higher incidence of Krukenberg spindle. Fundamentally, the authors studied the risk factors that transform a pigmentary syndrome into a pigmentary glaucoma, such as myopia, family history, etc. More than half the patients with pigmentary syndrome developed pigmentary glaucoma over time. Of 111 patients, 61 (55%) developed pigmentary glaucoma.

Campbell [36] thought that the rubbing of the iris against the zonular fibers due to the trapezoidal shape of the anterior chamber is the factor responsible for the peripheral atrophy of the iris pigment layer.

Calixto [37] and Calixto and Cronemberg [38] conducted detailed studies of pigmentary glaucoma. The latter study refers to retinal detachment in pigmentary syndrome and they quote Cardozo’s 1986 study in the bibliography, but make no mention of the first documented study that we know of, by Brachet and Cher-

met (1974) [39], or of our study published in Archivos de Oftalmología de Buenos Aires (1975) [40].

Richter et al. [41] share our opinion that it is a progressive glaucoma that worsens without treatment.

Richardson [42] divides the progress of pigmentary glaucoma into two stages, a first stage that he calls pigmentary dispersion, which is reversible if treated, and a second stage that is not reversible. In the first stage, there are transitory peaks of ocular pressure. The author advances a hypothesis about its pathogenesis based on the pathological anatomy: the endothelial cell is altered by phagocytosis of the pigment and separates from the connective tissue of the trabecula, leaving it bare.

All these bibliographical references (except Mann’s study) show that the pigmentation on the posterior face of the lens is an acquired phenomenon.

Mauksch’s observation in a set of twins and Koby’s in the mother and daughter point to something hereditary and congenital; this is in accordance with the anomalies presenting in the chamber angle that we described earlier. Pigmentation is a phenomenon that develops gradually, accompanying the congenital component in the chamber angle and ocular hypertension. We suggest reading Rosen’s papers [43], which are most useful for the biomicroscopy interpretation of this pigmentation that we have just described.

Epidemiology

Pigmentary glaucoma has a frequency of 1%–1.5% among the glaucomas, according to Scheie et al. [44] and Mapstone [45], cited by Campbell in the book by Ritch et al. [46]. In reality, this percentage cannot be so precise, because gonioscopy is not always performed, and this is the only method that enables a correct diagnosis of pigmentary glaucoma, as there can be Krukenberg spindle without pigmentary glaucoma. This is also true of the frequencies found in the literature on the amount of pigment dispersion (which is not pigmentary glaucoma) and pigmentary glaucoma; we have seen many patients classified as pigmentary dispersion, because the ophthalmologist took a single spot-check IOP during the day and did not carry out a DPC: daily pressure curve. This disorder affects young adult men between 20 and 45 years of age, with a deep anterior chamber and myopia. In women, it generally appears 10 years later.

Clinical Features: Diagnosis

We will examine the clinical manifestations of pigmentary glaucoma in the following order:

1.Intraocular pressure;

2.Anterior chamber;

3.Pigmentary syndrome;

4.Congenital anomalies of the chamber angle;

5.Refraction;

6.Heredity;

7.Possible associations with other ocular problems;

8.Pathological anatomy;

9.Pathogenesis;

10.Differential diagnosis.

Pigmentary glaucoma is a bilateral disease that occurs particularly in young men and women, generally under 50 years of age, at an average age of 48.3 (average age in men, 49; in women, 47.6). Of our 107 cases studied, 86 (80.4%) were men, and 21 (19.6%) were women.

The diagnosis of glaucoma is made as follows.

Intraocular Pressure

a.As in simple glaucoma, by accident, when measuring ocular pressure during a routine check-up.

b.Sometimes, because of a brusque increase in ocular pressure following medical dilatation of the pupil, due to a papillary block.

c.From symptoms of the congestive glaucoma type (the rarest ones). The patients have blurred vision, see colored rings around lights, etc.

d.It should be remembered that seeing colored rings is often not accompanied with hypertension in these patients and it is probably due, as Sugar says [48, 49], to the presence of a Krukenberg spindle in the cornea. Pressure varies between 21 and 50 mmHg; in rare cases it reaches 80 mmHg.

Since in all cases the initial ocular pressure gave pathological values, the daily pressure curve was taken not for diagnostic purposes, but only to check the effectiveness of medical or surgical therapy. In some borderline cases, it is necessary for the diagnosis of hypertension.

Anterior Chamber

The anterior chamber is characteristically deep and the iris assumes a concave configuration, most prominent in the mid-periphery. The shape of the anterior chamber is trapezoidal. This configuration results in rubbing the pigment epithelium against the zonular bundles, dislodging pigment granules [36].

Pigmentary Syndrome in the Anterior

Segment and Chamber Angle

1.Atrophy of the pigment epithelial layer of the iris [50];

2.Krukenberg spindle [51];

3.Pigmentation on the surface of the lens, in the peripheral part of its posterior face, irregular in shape, half-ring, whole ring, or double ring;

4.Chamber angle: a dark pigment ring in the scleral trabecular meshwork at the height of the Schlemm canal and goniodysgenesis;

5.Pigment dispersion in the anterior face of the iris.

Atrophy of the Pigment Epithelial Layer of the Iris

This is visible only by means of transillumination. This is very easy if the retroillumination of the iris is made during the examination with the slit lamp, using the lens of the eye as a diffusing medium for the light. To do this, a slit 3 mm high and 2 mm wide is focused on the pupil zone, so that the beam does not touch the iris tissue (retroillumination in the red field).

The direction of the beam of light must be normal to the eye and coincide with the axis of the observation microscope, as occurs with an ophthalmoscope; in this way, the red image of the pupil and the red image corresponding to the atrophic region of the iris will be obtained. If pigmentary glaucoma is already well developed, irregular but rounded zones of atrophy will be seen, sometimes isolated, with others running together in the periphery of the iris (atrophy in rings) (Fig. 20.26).

If pigmentary glaucoma is of recent onset and has developed little, the atrophy always starts in the inferior nasal region of both eyes and this is where it should be looked for. When we discuss the congenital component later, we will present this topographical location of the atrophy of the iris pigment layer in pigmentary glaucoma at onset (Fig. 20.27).