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

Figure 13.2a illustrates type I (Fig. 13.2b type II), with white lines delineating the various elements. Depending on the chamber angle, either trabeculotomy or combined surgery (trabeculotomy + trabeculectomy) is performed.

Figure 13.3 provides a summary of the two types. Figure 13.3a–c corresponds to type I congenital glaucoma: Fig. 13.3b, the goniophotograph, Fig. 13.3a, a schematic drawing of this goniophotograph, Fig. 13.3c, the pathologic anatomy of this condition. Figure 13.3d–f illustrates the diagram and pathologic anatomy of re-

fractory, type II congenital glaucoma. This gonioscopic differentiation in congenital glaucoma is necessary and knowledge of this will make for success or failure in surgery.

In our early experience, when we did only trabeculotomy, 30% of the children returned for consultation between 1 and 3 years later, the operation having failed, with an increase in IOP and greater axial length of the eye. Looking at the angle, we realized that all of them belonged to type II (apparently high insertion of the iris). This is why it is crucial for the surgical indication

to diagnose type I and type II based on the angle, since in type I trabeculotomy should be indicated and in type II a combined operation (trabeculotomy + trabeculectomy in the same session of surgery; see Chap. 16). I proposed this surgery for the first time in 1988 [1, 2].

Ten years later it was proposed by Mandal [3, 4] and in 2000 and 2001 by Meyer et al. and Kiefer et al. [5, 6]. Table 13.1 summarizes this, indicating the principal characteristics, to which are added the axial length and the corneal diameter.

The Use of SL-OCT in Diagnosis

and Follow-Up of Congenital Glaucomas

The recent appearance in the market of a new technology applied to the anterior segment has opened the way to the coherent light tomography. The SL-OCT (slit lamp optical coherence tomography) is coherent light tomography adapted to a conventional slit lamp, produced by Heidelberg Engineering. The Visante is another version of this instrument manufactured by Zeiss, which we have not used.

One of the advantages of the SL-OCT over the Visante is that it is adapted to a slit lamp and is not an additional instrument. The ophthalmologist, used to using the lamp, knows that the slit indicates the section that is seen over the monitor to the right. The lightbeam is located over the structure to be studied, and the ocular section can be seen at that point. In addition, in contrast to the Visante, the SL-OCT makes it possible to perform the Budenz maneuver of indentation gonioscopy, which is fundamental for deciding whether the blockages are functional or organic. Figure 13.4 shows the SL-OCT and Fig. 13.5 the au-

thors studying a child with congenital glaucoma under sedation with Sevorane and monitoring with the same instrument.

Since the SL-OCT can be used in nontransparent media, it is very useful for observing the chamber angle, even in cases where there is a significant corneal edema. Figure 13.6 shows a 2-month-old girl who consulted for pure type II congenital glaucoma (apparent high insertion of the iris) with ocular pressure at 38 mmHg and corneal edema. The gonioscopy can be seen in the genioscopy, with poor resolution due to the edema, while the SL-OCT shows the apparent high insertion of the iris, with peripheral atrophy of the iris, in the same eye at the same time.

The SL-OCT gives a clear idea of the pathogenesis of congenital glaucoma both in the pure congenital glaucomas and in secondary glaucomas or those associated with ocular malformations. Figure 13.7 illustrates type I congenital glaucoma (from pathological mesodermal remnants) with excellent clarity in the tomograph. Pure type II congenital glaucoma (from apparent high insertion of the iris) can be seen in Fig. 13.8, clearly showing the difference between the two phenotypes.

Corneal alterations can also be seen with high definition, even though they are microscopic or when there is significant opacity in the media. In the case of Haab striae, when a cross-section is made, the limit of the Descemet membrane can be seen at both sides of the striae, which is visible tomographically as an intracorneal slit or canal (Fig. 13.9).

On the other hand, when the media are not clear, as for example in the leukomas that can accompany congenital aniridia, there are cases in which in anterior segment biomicroscopy, the leukoma prevents a view of the anterior chamber, as shown in the example. Nonetheless, the SL-OCT not only shows its structures, but also the tube of the Ahmed valve that the patient has implanted, with no contact with either the cornea or the crystalline lens (Fig. 13.10).

The same case of secondary congenital glaucoma or associated with aniridia and leukoma can be seen in Fig. 13.11, after performing a penetrating keratoplasty. The biomicroscopy shows how the leukoma has been removed with the transplant and the SL-OCT shows the donor button sutured to the receptor bed, with the tube in the anterior chamber that has no contact with the donor button.

In aniridia, it is also possible to see the detention of the Descemet membrane where the central leukoma begins (Fig. 13.12) and the colobomatous lens, or pearshaped lens, which is incorrectly mentioned in several texts as superior lens subluxation (Fig. 13.13).

In the angles of normal newborns, there is peripheral thinning of the iris, because at the time of birth the mesodermal layer of the iris is not fully developed. This can be seen in Fig. 13.14. Figure 13.15 shows a different picture, corresponding to a case of peripheral atrophy of the iris in pure type II congenital glaucoma.

In Peters syndrome, congenital glaucoma secondary to or associated with ocular malformations, it is possible in its forme fruste to see the dyscoria, with the pupil drawn toward 12 o’ clock behind a partial leukoma, in the biomicroscopy of the anterior segment (Fig. 13.16). The SL-OCT shows the asymmetry in the iris and the posterior ulcer of the cornea described in this syndrome (Fig. 13.17).

In cases in which Peters syndrome is not fruste, a much larger central leukoma is commonly seen (Fig. 13.18) as well as synechiae or adherences between the pupil edge of the iris and the rear face of the cornea, as in Fig. 13.19.

Fig. 13.14 Peripheral thinning of the iris, because at the time of birth the mesodermal layer of the iris is not fully developed

Fig. 13.16 Fruste Peters Syndrome, with central leucoma and dyscoria

Fig. 13.15 Peripheral atrophy of the iris in pure type II congenital glaucoma

Fig. 13.17 Posterior ulcer of the cornea as described in Peters Syndrome

Fig. 13.18 Large leukoma is commonly seen in not fruste Peters Syndrome

Fig. 13.19 Synechiae or adherences between the pupil edge of the iris and the rear face of the cornea

In late congenital glaucomas, pigmentary glaucomas are found that are characterized by having a trapezoidal anterior chamber and positive peripheral transillumination of the iris. In Fig. 13.20, the anterior chamber can be seen with this aspect, while in Fig. 13.20 the lack of substance in the peripheral iris can be observed, which probably originates the positive peripheral transillumination in these glaucomas.

Among the postsurgical complications are hypothalamia or athalamia, generally seen when atropine was not used during surgery or when there is a positive Seidel phenomenon from poor conjunctival closing. It is important to check both aspects in the surgery with these children, since each reintervention requires general anesthetic.

A case of athalamia can be seen in Fig. 13.21, where the iris was in contact on both sides with the rear face of the cornea, and there is only aqueous humor between the lens and the corneal endothelium. Figure 13.22 shows hypothalamia with hyphema, and the iris can be observed starting to separate from the rear

face of the cornea. On the right edge (lower in the eye), a hyphema has accumulated, leaving the visual axis free (blood in red and yellow).

Another frequent complication is when the tube of the Ahmed valve slips out of the anterior chamber. This usually happens when the tube is not left in long enough so that it does not slip out either with the accelerated growth of the ocular globe in decompensated congenital glaucoma or with the normal growth that occurs in the ocular globe of a child. Figure 13.23 shows that the Ahmed tube escapes from the anterior chamber toward the intrascleral portion.

To sum up, this new technology, because it has the qualities of a rapid examination method, high resolution, no need for clear media, and above all, it does not come in contact with the eye, is a very useful tool for evaluating congenital glaucomas in their diagnosis, follow-up, and postsurgical assessment. We believe that it is also superior to ultrasonic ultrabiomicroscopy (UBM) applications, especially in the pediatric glaucoma population.

Fig. 13.21 A case of athalamia where the iris was in contact on both sides with the rear face of the cornea

Fig. 13.23 Ahmed tube escapes from the anterior chamber towards the intrascleral portion

References

1.Sampaolesi R (1991) Glaucoma, 2nd edn. Editorial Medica Panamericana, Buenos Aires, Argentina

2.Sampaolesi R (1988) Congenital glaucoma. Long-term results after surgery. Fortschr Ophthalmol 85:626–631

3.Mandal AK (1996) Surgical results of combined trabecu- lotomy-trabeculectomy for developmental glaucoma. Primary combined trabeculotomy and trabeculectomy in a single session. Ophthalmology 105:974–983

4.Mandal AK (2003) Outcome of surgery on infants younger than 1 month with congenital glaucoma. Ophthalmology 110:1909–1915

Fig. 13.22 Hipothalamia and hyphema, the iris starts to separate from the cornea on the right side

5.Meyer G, Schwenn O, Grehn F (2000) Trabekulotomie beim Kongenitalem Glaukom. Ein Vergleich zur Goniotomie. Ophthalmologe 97:623–628

6.Kiefer G, Schwenn O, Grehn F (2001) Correlation of postoperative axial length growth and intraocular pressure in congenital glaucoma. A retrospective study in trabeculotomy and goniotomy. Graefes Arch Clin Exp Ophthalmol 239:893–899

7.Kozlov VI, Bagrov SN, Anisimova SY et al (1990) Nonpenetrating deep sclerotomy with collagen. IRTC Eye microsurgery. RSFSR Ministry of Public Health, Moscow 4:62–66