Contributor: Gordon K. Klintworth
Secondary angle closure glaucoma (secondary closed angle glaucoma) is divided into secondary angle closure glaucoma with pupillary block, secondary angle closure glaucoma with ciliary block and secondary angle closure glaucoma without pupillary block.
Secondary angle closure glaucoma with pupillary block. Several disorders of the eye (iritis, traumatic lens displacement, uveal effusion, retinal detachment, persistent primary hyperplastic vitreous, retinopathy of prematurity) can obstruct the flow of aqueous from the posterior chamber to the anterior chamber. Posterior synechiae may develop between the iris and lens, or the vitreous (in the aphakic eye) during episodes of iritis. Especially if secluseo pupillae develops iris bombé follows and the intraocular pressure becomes elevated. Sometimes occluseo pupillae follows intense or recurrent episodes of iritis and iris bombé occurs without central posterior synechiae. In such acses posterior synechiae are usually present together with annular adhesions between the iris and lens (secluseo pupillae) and the the presence of a connective tissue menbrane across the pupil (occluseo pupillae). An episode of acute primary angle closure glaucoma [glaucoma - primary narrow angle] may be followed by iritis and this needs to distinguished clinically from glaucoma secondary to iritis with pupillary block. In glaucoma secondary to iritis with pupillary block miosis is present and the fellow eye has a normal anterior chamber. In acute primary angle closure glaucoma mydriasis is present and the opposite eye the anterior chamber is shallow.
Lens-related glaucoma. In an advanced stage of many cataracts (senile or infantile cataracts) the lens becomes swollen and can lead to glaucoma. Even in eyes with a deep anterior chamber, but particularly in those predisposed to angle closure glaucoma, a swollen lens displaces the iris forward leading to a shallow anterior chamber and a blockage of the pupil. The pupil can also become occluded by a traumatic or spontaneous displacement of the lens (ectopia lentis) or pseudophakos in eyes with aphakia. A traumatically dislocated lens can become displaced into the anterior chamber. The crystalline lens becomes spontaneous displaced in several diseases (Marfan syndrome, homocystinuria, Weill-Marchesani syndrome, ectopia lentis et pupillae) in which the zonules are abnormal. Even a lens with microphakia and spherophakia can cause intermittent or chronic secondary glaucoma by obstructing the pupil in a "ball valve" manner and interfering with the flow of aqueous into the anterior chamber. When the lens is displaced posteriorly or laterally vitreous is frequently also displaced into the pupil and either or both of these structures interfer with aqueous flow through the pupil. Sometimes the vitreous face ruptures and l anteriorly displaced vitreous fills the pupil and a major portion of the anterior chamber obstructing the flow of aqueous into the angle. Glaucoma frequently accomanies a traumatic lens dislocation not only because of the effect of the displaced lens, but also beacuse a direct injury to the trabecular meshwork and angle recession .
Secondary angle closure glaucoma with ciliary block.
Eyes with shallow anterior chambers and angle-closure glaucoma may be made worse by medical or surgical therapy, especially filtering surgery [glaucoma - ciliary block]. Such eyes can be softened by aspiration of pockets of fluid within and behind the detached vitreous. The hyaloid seems to become compressed against the ciliary body at the vitreous base and this prevents an anterior flow of aqueous, which then seems to be directed backward through the vitreous or through a break in the anterior hyaloid near its attachment to the ciliary body.
Secondary angle closure glaucoma without pupillary block.
Without blocking the pupil the iris may adhere to the trabecular meshwork and adhesions may form where the iris makes contact with the trabecular meshwork giving rise to glaucoma. This may occur if the anterior chamber becomes flattened following an accidental or surgical perforating wound through the cornea or corneoscleral limbus. It also occurs rarely when a tumor or cyst in the ciliary body displaces the iris anteriorly.
An unusual type of angle closure glaucoma occurs when the anterior chamber is narrow at the periphery (the plateau iris). When the pupil dilates the iris crowds the angle, leading to its obstruction.
In closed-angle glaucoma, contact between the peripheral iris and the inner surface of the trabecular meshwork prevents the outflow of aqueous in the region of attachment. Iris bombe or anterior bowing of the iris is seen when the pressure in the posterior chamber is much higher than in the anterior chamber. The pressure difference is a consequence of pupillary block or restriction of aqueous flow through the pupil.
Peripheral anterior syncechiae occur if acute angle closure glaucoma is not relieved within hours. Also, intermittent subclinical attacks can lead to gradual development of synechiae resulting in a type of chronic angle-closure glaucoma referred to as "creeping" angle-closure glaucoma.