Pseudoexfoliation syndrome for the comprehensive ophthalmologist: Intraocular and systemic manifestationsHistorical image
Section snippets
Background
The history of PEX syndrome starts with the Finnish ophthalmologist Lindberg,3 who referred to observations of Fuchs, Meller, and Axenfeld, but it was Lindberg who defined the changes on the anterior lens capsule in precise drawings. Vogt1, 2 emphasized the association with glaucoma capsulare; Sampaolesi4 elaborated on melanin dispersion and changes of the blood-aqueous barrier; Tarkkanen5 focused on the involvement of the ciliary processes; Ringvold6 showed PEX material in the conjunctival
Intraocular involvement
As ophthalmic clinicians, we are mainly interested in the practical consequences of PEX syndrome. The clinical relevance of our observations is better understood if we look beyond the surfaces of biomicroscopy and perform basic, thorough, clinicohistopathologic correlations. Our didactic terminology is supposed to emphasize the participation of the various tissues in one underlying process (Table 3).
Intraocular complications
Many ophthalmologists routinely still associate PEX syndrome with open-angle glaucoma. It therefore needs to be emphasized that PEX is not only important in the various types of glaucoma (including angle-closure glaucoma) but also for the cataract surgeons in extracapsular surgery (e.g., lens luxation, zonular ruptures, posterior synechiae, incomplete mydriasis, pseudouveitis), for neuro-ophthalmologists (reduced and asymmetric pupillary action), for cornea specialists (corneal
Types of glaucoma
Glaucoma usually occurs in the presence of an open angle, but angle-closure glaucoma via pupillary block may be overlooked frequently.35, 36 Angle closure via ciliary block, without intraocular surgery, does occur but seems to be a relatively rare phenomenon.37, 38 The pathogenetic mechanisms of secondary open-angle glaucoma with PEX syndrome may involve several factors (Table 6). The PEX-associated glaucoma is well differentiated from primary open-angle glaucoma not only clinically but also
Cataract and lens
Lens involvement has several features:
- 1.
Cataract. Increased lens opacification is suggested to be associated with PEX by most studies. The predominant type of cataract in PEX syndrome has been reported to be nuclear sclerosis.39, 40
- 2.
Phakodonesis and spontaneous lens luxation. Weakening of the zonular support predisposes to phakodonesis41 and spontaneous lens dislocation.42, 43
- 3.
Extracapsular cataract extraction: zonular dialyses and vitreous loss. The switch from intracapsular to extracapsular
Corneal endotheliopathy
Corneal endotheliopathy results from a reduced density of the corneal endothelium and morphologic alterations, including the direct involvement of the endothelial cells in PEX syndrome, which increases the risk of early corneal endothelial decompensation, even with only moderate rises in intraocular pressure (e.g., after mydriasis [Table 6]). It differs from Fuchs’ corneal dystrophy in several features (Table 8).49 Puzzling and yet unexplained is the occurrence of PEX material in patients
Pseudoexfoliation-iridopathy
Pseudoexfoliation-iridopathy leads to blood-aqueous barrier leakage and symptoms that include pseudouveitis, melanin dispersion, poor pupillary motility, and reduced oxygen levels in the aqueous (Table 6). These changes as well as adhesive PEX accumulations on the surfaces of iris and lens induce posterior synechiae before and after surgery.
Retina and pseudoexfoliation syndrome
Both the increased rate of vitreous loss and the more frequent need of Nd:YAG capsulotomy for secondary cataract could be expected to enhance the risk of retinal detachment. The PEX syndrome might, therefore, be regarded as a risk factor for the development of retinal detachment (Table 6). Furthermore, central retinal vein occlusion appears to be more common in patients with PEX syndrome.51, 52
Principal complications
Chronic complications of PEX syndrome Table 6, Table 7 are known as ocular hypertension and secondary open-angle glaucoma since Lindberg3 and Vogt.1, 2 Other chronic alterations like pseudouveitis, melanin dispersion, poor pupillary motility, and posterior synechiae may deserve more attention than they generally get. In addition, acute complications may be part of the disease, such as spontaneous lens subluxation and luxation, vitreous loss during extracapsular surgery, and corneal endothelial
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