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

This is the mother of the 3-year-old child in clinical case no. 2. Given the dominant nature of the hereditary pattern, in these cases we also examined the mother, with the following findings:

As for genetic background, the patient only knows that there is a blind maternal uncle and also a blind maternal grandmother.

The patient’s IOP was regulated with medical therapy.

A 5-year-old male was diagnosed with Rieger mesodermal dysgenesis (degree III) that progressed in a fashion similar to essential atrophy of the iris.

This patient was referred to us by our colleague Rodolfo Laje Weskamp Irigoyen Jr., who has given permission for this case report. Upon routine examination, this ophthalmologist found an IOP of 50 mmHg in both eyes, accommodative esotropia with hyperfunction of the oblique major muscle and facial asymmetry (see Fig. 21.7a, b and compare them with the appearance of the child in Fig. 21.6a, b).

Though ocular hypertension typically appears late in Rieger syndrome, in this child it must have appeared early, since, as shown by echometry in Fig. 21.7c, d, the axial length was abnormal.

Gonioscopy shows goniodysgenesis with persistence of mesodermal pathologic tissue up to the Schwalbe line in both eyes. The morphology of this chamber angle evolved to such an extent that synechiae appeared on the posterior corneal surface (Fig. 21.7e) and finally led to polycoria identical to that seen in essential atrophy of the iris (Fig. 21.7f).

There is iris hyperplasia with absence of the frill of the iris in both eyes, thereby leaving the avascular and vascular pillars uncovered.

I have seen this type of progression of a case of Rieger dysgenesis as if it were an essential atrophy only once, and I have found reports by Kwitko [14] and Alkemade [6].

There are no tears either in the Descemet membrane or the endothelium.

This child was started on therapy with beta blockers 0.5% and Pilocarpine 0.5% from May 1982. The IOP went down to 12 mmHg in the right eye and 22 mmHg in the left eye. Since in December 1982 the IOP of the left eye rose to 34 mmHg, he underwent combined surgery (trabeculotomy + trabeculectomy). The IOP was regulated at 12 mmHg in that eye and the visual

acuity improved to 20/20. The diurnal pressure curve remained regulated in both eyes.

One year later, in December 1983, the IOP of the left eye remained normal while in the right eye it had risen to 20, 22 and 26 mmHg. This situation continued until September 1984, when the IOP of the right eye rose to 36 mmHg. With combined surgery, the IOP was regulated but only for 1 month. Then, in the left eye, operated on previously and with its IOP regulated, there ap-

peared six triangular goniosynechiae, iris resorption, and a new peripheral pupil at 6 o’ clock nasally, a picture identical to that of essential atrophy of the iris.

Figure 21.7 g, h, show the visual field examinations of the left eye performed with Program G1 and Bebie curve, which evidence great impairment. The optic nerve had a cup/disc ratio of 4/6 in the right eye and 5/6 in the left eye.

Fig. 21.7a–h (continued) e, f Gonioscopies showing progression toward the development of goniosynechiae on the posterior corneal surface, which finally led to a polycoria identical

to that present in essential atrophy of the iris. g, h Gray-scale visual field of the left eye and program G1; the Bebie curve shows a severely impaired retinal sensitivity

Clinical History No. 6

This 18-year-old female consulted for refraction adjustment in December 1980. Her mother had noticed a white thread on the left pupil, and though she had mentioned this to other ophthalmologists consulted previously, they had stated it was not a matter of concern (Fig. 21.8).

The visual field examination performed at the time was the Goldman perimetry, which revealed degree 3

damage in both eyes, with a loss in the upper hemifield and concentric isopter narrowing.

The cornea in both eyes had no edema or tears in the endothelium or Descemet membrane.

The patient was started on acetazolamide, four 250mg pills daily, pilocarpine 1% q.i.d. and levoepinephrine 2% b.i.d. Since the IOP could not be reduced below 40 mmHg in the right eye or below 30 mmHg in the left eye, she underwent bilateral combined surgery, which regulated the IOP as shown by single-spot checks yielding 16 and 18 mmHg, respectively. The diurnal pressure curve was also regulated. The visual acuity remained unchanged and the visual field stopped its progression. There was a follow-up over 8 years starting in 1980.

The diagnosis was Rieger mesodermal dysgenesis (degree 3). This argues in favor of the vital importance of gonioscopic examination of the chamber angle and the interpretation of its results for diagnosis.

Clinical History No. 7

The 44-year-old female patient came for consultation because she had had far vision difficulties for 3 years. In a previous visit with another ophthalmologist, bilateral ocular hypertension was detected and she was referred to us. She had had hearing problems since she was a child, her nose was normal, the interpupillary distance was 62 mm, and the distance between the inner canthi was 35 mm (Fig. 21.9).

The IOP of the right eye was regulated with miotic agents while in the left eye a trabeculectomy was performed.

Posterior embryotoxon, mesodermal dysgenesis and partial coloboma of the iris were discovered. In some cases of posterior embryotoxon, sometimes associated with mesodermal dysgenesis, in the nasal or temporal area, at the horizontal meridian, there is a small trans-

parent crescent-shaped area in the sclera, with its concavity coincident with that of the limbus.

Normally, at the limbus, the sclera comes closer to the cornea at the superficial part than at the deep part and thus covers the structures of the chamber angle. In contrast, in this anomaly, the situation is the opposite. At the crescent, the structures of the chamber angle can be seen through it (Fig. 21.10).

Kraupa [15] was the first to describe this malformation in the nasal and temporal areas. Kayser [16] described the same when he studied a case of posterior embryotoxon with pupillary membrane remnants, and he stated that he could see the chamber angle directly from outside. Ascher [17] coined the name “partial coloboma of the limbus” for this anomaly and said he was able to see the Schlemm canal directly, due to the lack of scleral tissue in that place.

20/30 with sph –9 × 90°

26 mmHg

II

Gonioscopy revealed the appearance of Rieger mesodermal dysgenesis. At 6 o’ clock the whole structure of the chamber angle was abnormal and at the inferonasal area there was a pigment ectropion covering the pupillary area of the iris. All this area, from 11 o’ clock to 6, and

at 9 o’ clock was covered with a transparent nonhyaline membrane, revealing a paler hazel color of the iris. In another area of the chamber angle, there was persistence of pathologic mesodermal tissue up to the Schwalbe line

Fig. 21.10 Posterior embryotoxon, mesodermal dysgenesis and partial coloboma of the limbus. In the left nasal area, greater magnification reveals the coloboma and the characteristic cord

of the posterior corneal surface at the level of the Schwalbe line. The iris hypoplasia is very marked in the peripheral part, and it uncovers the pupil constrictor muscle at the central part

Clinical History No. 8

This clinical history reports a 49-year-old woman who was referred to me by Dr. Nicoli and Dr. Travi. She was diagnosed with bilateral late congenital glaucoma with retinitis pigmentosa.

As shown by Fig. 21.10, this is a case of posterior embryotoxon with atrophy of the peripheral quarter of the iris, similar to mesodermal dysgenesis but with no pupil deformities. Goniosynechiae up to the Schwalbe line, pronounced iris peripheral atrophy make the pigmentary layer visible and the major arterial circle at some sectors.

Medical therapy regulated IOP in the right eye. In the left eye, filtering iridectomy successfully regulated IOP.

The genealogic tree shows that the patient’s parents were first cousins, the maternal grandfather had retinitis pigmentosa and two of the patient’s three brothers have retinitis pigmentosa.

Peters Anomaly

This is a congenitally defective formation of the Descemet and endothelium membranes, which, at the center of the cornea, give rise to a ring-shaped iris synechia and consequently to a central leukoma and secondary glaucoma due to athalamia. Diameters of

13–14 mm and corneal central disciform opacity are apparent. The IOP ranges from 25 to 35 mmHg.

This syndrome was described by Peters [18] as a glaucoma secondary to peripheral athalamia caused by an anterior ring-shaped iris synechia at the margins of a congenital formation defect of the Descemet membrane. In his book on glaucoma (1930) [19], in the chapter on hydrophthalmus, Peters quotes his 1906 description as a congenital corneal opacity, the consequence of a formation defect of the Descemet membrane.

In 1899, Von Hippel [20] described it as an internal inflammatory corneal ulcer. These opacities can be very large, as in the case reported by Buck [21], and lead to an enlargement of the eyeball, as observed in a series of cases accompanied by chamber angle and iris disorders.

Meisner [22] found a corneal opacity in a case of hydrophthalmus with defective formation of the Descemet membrane with an absence of crystalline lens. He attributed this to defective closure of the lens vesicle leading to its absence. The absence of normal chamber angle structures has been described by Appelmans et al. [23].

Waring et al. [13] described the different steps that may be involved in this anomaly: posterior keratoconus, corneal tissue defect and leukoma, iris adhesions at the margin of the leukoma, and lens apposition to the leukoma. As regards pathogenesis, the papers by Townsend et al. [24–26] are highly recommended.

Diagnosis

Diagnosis is generally easy, but differential diagnosis with other congenital corneal opacities should be con-

-sidered, for example:

- Hydrophthalmus with hazy cornea; - Parenchymatous keratitis;

Inflammatory leukoma with staphyloma secondary - to gonococcal conjunctivitis;

- Epidermoid (corneal mesodermal metaplasia); Congenital corneal staphyloma or leukomatous keratectasia.

Demaske and Müller, at the Meeting of the German Society of Ophthalmology, reported the following case [27] (kindly provided by the authors).

Clinical History No. 9

This 18-month-old girl weighed 2.960 kg after a fullterm, normal pregnancy and measured 50 cm in length. her mother had a cleft palate. She had a 2.5-year-old healthy brother.

In her right eye, there was spherical congenital corneal staphyloma, with a corneal diameter of 10 mm, absent Descemet membrane (Fig. 21.11a), and anterior iris synechia. In her left eye, there was Peters anomaly, ring-shaped central opacification with an almost circular iris synechia; the iris stroma was visible; corneal diameter was 10 mm.

Ultrasonography in both eyes showed that the vitreous body was free. The left eye had a greater length than normal (5 mm above normal values).

In the right eye, the staphyloma was reduced with cryotherapy and a penetrating keratoplasty 8.5 mm in diameter was performed 15 days later (Fig. 21.11b, c).

At the beginning, the graft was smooth and remained transparent for a few weeks.

Three months later, there were folds on the posterior graft surface and mild parenchymal opacity from the margin.

Four months later, a small staphyloma appeared at the lower part of the graft.

After 9 months, the opacity of the staphyloma was the same size as before surgery.

At month 11 postoperatively, the eye was enucleated due to chronic blepharoconjunctivitis and a very pronounced oculodigital phenomenon. Histology revealed a corneal epithelium of varying thickness with vascular growth in the basal cell layer and Bowman membrane tears. Behind this there was conjunctival tissue that was filled with collagen and vascularized, which included part of the iris and loose pigmentary cells. The Descemet membrane was absent and it was homogeneously PAS-positive.

Clinical History No. 10

This 5-day-old boy was full-term, the child of healthy parents: a 23-year-old father and 22-year-old mother. He had a buphthalmic right eye with a disciform central leukoma.

The corneal diameter of the right eye was 14 mm. There was a white disciform leukoma 9 mm in diameter. At the center of the leukoma, and concentric to it, there was a yellowish 3-mm-diameter disc with a darker center (Fig. 21.12). Slit-lamp examination revealed a bullous keratopathy in its early stages. Outside the leukoma, in the 2.5 mm left on each sides, the cornea was transparent and the peripheral part of the iris with its typical dark triangles can be seen, as well as the area of iris tissue between them and the root insertion, though the latter was larger than usual. The dark tri-

angles form, distally, a festooned line. The whole iris is visible, extending from the periphery of the leukoma to the limbus, and it was attached to the posterior corneal surface. This means that there was peripheral athalamia.

The IOP was 25 mmHg, while in the fellow eye, which was apparently normal, it was 6 mmHg, with a corneal diameter of 10 mm and an incomplete posterior embryotoxon. The chamber angle, with arrested development, showed dark areas continued by a short iris root. There were pathological mesodermal remnants inserted at the Schlemm canal. The iris tissue was not developed, while both the Henle layer and the superficial mesodermal layer were developing. This leaves the whole vascular tree of the iris completely visible: part of the greater arterial circle of the iris, radial vessels and the complete lesser arterial circle of the iris.

Fig. 21.12 a Cornea of a case of Peters anomaly, b in a view from its anterior and posterior surfaces. Anatomic piece from the cornea of the patient described in clinical history no. 10. On the anterior surface there is a leukoma. The iris (dark) becomes transparent at the pericentral part, and in the central

area there is a dehiscent zone. On the posterior surface the iris can be seen, tightly attached to the posterior corneal surface. c Diagram of Peters anomaly, posterior corneal ulcer with or without cataract

Therapy

After 2 days, a perforating corneal graft 10 mm in diameter was performed (when the infant was 9 days old). The surgical protocol is the following:

1.A 10-mm trephine is used to cup the superficial corneal layers.

2.The anterior chamber is opened.

3.The section is completed through the full corneal thickness with Troutman scissors.

4.The cornea is attached to the iris around its whole circumference, at the external third, and is verified. A 2-mm surface in the inner corneal wall is left free.

5.A loop is created in the iris with Vannas scissors, close to its insertion in the cornea; a circular section is made by introducing one blade of the scissors through it at this same level.

6.A transparent crystalline lens becomes visible through the wound, with a very small anterior polar cataract. The ocular fundus is illuminated in red. Figure 21.12 shows the piece removed in a view through its anterior and posterior surfaces.

7.The donor cornea is implanted with 4 silk sutures at 3, 6, 9, and 12 o’ clock, completed with a nylon continuous suture.

8.Upon completion of surgery, the chamber is fully formed.

Follow-up examinations took place after 5 days.

The graft was transparent, the anterior chamber was formed and the fundus was illuminated in red.

The IOP was 6 mmHg in both eyes. This demonstrates that it was a secondary glaucoma to peripheral athalamia.

Follow-Up Examination After 10 Days

The IOP was 7 mmHg in both eyes. At the inferonasal part of the recipient cornea, there were two small staphylomas. A small incision was placed in them and the margins were attached with virgin silk sutures.

Pathologic Anatomy

The cornea shown in Fig. 21.12 was embedded in paraffin and stained with hematoxylin-eosin, PAS, and trichrome stain. The microphotographs were obtained with phase contrast. Later the following findings were made:

Epithelium

The basal layer was edematous (Fig. 21.13). At the central area of the leukoma, there was a yellowish disc with a dark center (Fig. 21.12). Histology revealed that the basal cells and the basement membrane were destroyed, and there was a serious anomaly in the underlying Bowman membrane (Fig. 21.14).

Follow-Up Examination After 20 Days

The graft was transparent, the staphyloma described above was closed. The IOP was 6 mmHg in both eyes.

Follow-Up Examinations After 4 Months

Fig. 21.13a,b Peters anomaly, corneal epithelium (original preparation). a Epithelium with preserved basement membrane, absence of Bowman membrane. There is a small aqueous infiltration into basal cells. b Another area where the epithelium has lost the basement membrane. The aqueous infiltration (edema) is much more pronounced