Posterior Segment Complications of Cataract Surgery by Unknown

Author:Unknown
Language: eng
Format: epub
ISBN: 9789811510199
Publisher: Springer Singapore

7.5 Pathogenesis

The risk of developing endophthalmitis depends upon factors such as the patient’s immune response, virulence of the causative organism, and the use of perioperative antibiotics. Once infective organisms gain access inside the eye, damage to the ocular tissues results from the direct effect of bacterial replication and release of inflammatory mediators. Bacterial endotoxins stimulate cytokine release resulting in a breakdown of the blood-aqueous and blood-vitreous barriers. This is followed by invasion of leucocytes inside the eye causing a diffuse liquefactive necrosis. A polymorphonuclear cell infiltrate is predominant in bacterial infections and Gram’s stain may reveal numerous bacteria in the vicinity of necrotic debris. In contrast, fungal infections are characterized by slow progression, granulomatous inflammation, and predominant mononuclear cell infiltration. Special stains such as Gomori’s Methenamine Silver (GMS) or Periodic Acid Schiff (PAS) can be used to demonstrate fungal elements.

Inflammatory exudates lead to vitreous opacification, posterior vitreous detachment, and abscess formation. Inflammation may extend to structures such as the iris, ciliary body, and retina. Proliferation of the ciliary epithelium and extension of the fibrovascular membranes along the scaffold provided by the anterior hyaloid eventually forms cyclitic membranes. These membranes contract causing traction on the ciliary body. This results in ciliary and choroidal detachment leading to hypotony. Eventually, vitreous organization, shrinkage and traction on the retina and choroid can result in retinal and/or choroidal detachment. These changes if untreated eventually lead to phthisis bulbi.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.