**1. Introduction**

Malignant glaucoma was described for the first time and named so by Albrecht von Graefe in 1869 [1]. It is characterized by normal or increased IOP *(intraocular pressure)* associated with axial shallowing of the entire anterior chamber in the presence of a patent peripheral iridotomy [2,3]. The pathology is based on the existence of a block for normal flow of aque‐ ous humour, which results in the accumulation of aqueous at an improper location in the eyeball [4]. The proposed mechanism involves a misdirection of aqueous humour passing posteriorly into or behind the vitreous gel [5]. This is a dynamic process, and if untreated, causes loss of vision. Local hypotensive treatment does not cause normalization of IOP, and conventional glaucoma surgery proves to be ineffective [3].

#### **1.1. Classification**

Classification includes phakic, aphakic, and pseudophakic malignant glaucoma. Aphakic malignant glaucoma is the onset of symptoms after a cataract surgery or the persistence of symptoms after treatment of phakic malignant glaucoma through the cataract extraction [6]. "Non-phakic malignant glaucoma" is a general term used for both types: aphakic and pseu‐ dophakic malignant glaucoma [6]. The term *malignant-like glaucoma* was proposed for cases with a known cause of forward displacement of the lens along with the frontal surface of the vitreous body other than the "trapping" of humour inside of the vitreous body [7]. There also exists a classification of malignant glaucoma into that occurring after surgical interven‐ tion and without such intervention [8].

The not fully known etiology of the process creates difficulties in the standardization of no‐ menclature. Certain authors suggest that the malignant glaucoma group should exclude cas‐ es in which e.g. pupillary block or choroidal detachment has been stated [9]. Others believe that using this term to encompass a broader spectrum of eye diseases will create a better un‐

© 2013 Rękas and Krix-Jachym; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

derstanding of the pathophysiology and the relationship between pathologies with similar clinical pictures [4].

Choroid – the choroid has a lobular structure with a tendency for accumulation of blood and thickening when outflow is impaired. Secondary, ciliary body and iris rotate to the front in patients with malignant glaucoma [24], closing access to the filtration angle from the back. Vitreous body – Slit-lamp examination of the vitreous may reveal optically clear areas with‐ in the vitreous body – reservoirs of aqueous humour trapped in its gel structure [3], which may be confirmed on ultrasound [25]. In aphakic eyes, the anterior surface of the vitreous

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The anterior and posterior chambers and their relationship – total obliteration of the posteri‐ or chamber by the vitreous and a highly resistant hyaloid membrane may be observed in

The anatomic and functional differences of predisposed eyes seem to be a significant factor for determining the occurrence of malignant glaucoma. The following predisposing factors have been described, among others: axial hyperopia [27], nanophthalmos [28], disorders of

It is considered that malignant glaucoma is related to a special eye anatomy (small eye phenotype). Lynch et al. stated that it occurs more frequently in small eyes with an ana‐ tomically narrow iridocorneal angle [11]. Many nanophthalmic and RAM eyes have nar‐ row angles with crowded structures in the anterior chambers. Typically, the lens is of normal or increased thickness, leading to a high lens:eye ratio and this crowding results in a shallow anterior segment that predisposes to angle-closure glaucoma [21]. In micro‐ phthalmos, due to small eye size, the increase in the size of the lens with age is critical,

body may directly adhere to the ciliary processes [3].

anatomical proportions in the anterior chamber [18].

**Figure 1.** Normal eye, relative anterior microphthalmos and nanophthalmos.

aphakic and pseudophakic eyes [26].

**3. Predisposing factors**

#### **1.2. Occurrence**

According to literature, malignant glaucoma develops in 2% to 4% of patients with a his‐ tory of acute or chronic angle-closure glaucoma that have undergone filtration surgery [3]. In own material, consisting of a total of 1689 penetrating and non-penetrating opera‐ tions, performed as glaucoma surgery alone or combined with cataracts, malignant glau‐ coma occurred in 1.3% of all eyes after surgery. After penetrating surgery this complication was noted in 2.3% of eyes. It was also observed after laser iridotomy [10], phacoemulsification of cataract [11], posterior capsulotomy using a Nd-YAG laser *(Neody‐ mium-yttrium-aluminum-garnet laser)* [12], cyclophotocoagulation [13], after implantation of large-sized IOLs *(intraocular lens)* [14], after local application of miotics [15], after suturol‐ ysis [16], and even in eyes that did not undergo surgical procedures [17]. Cases of malig‐ nant glaucoma have also been described in eyes in which glaucoma had not been established earlier [11].

Malignant glaucoma occurs significantly more frequently after penetrating surgery than in the case of non-penetrating surgery, after just the glaucoma surgery than after treatment combined with phacoemulsification, as well as in eyes with narrow angle glaucoma. It was stated with greater frequency among women, which may be related to the lesser dimensions of the anterior segment of the eyeball in this group of patients [18]. This complication can take place at various times after the operation, sometimes immediately, and sometimes after one year has passed or even after a longer period of time [3].
