As a relatively acellular and completely avascular structure, the vitreous is generally not a primary site for the initiation of inflammatory disorders. It does become involved secondarily in inflammatory conditions of adjacent tissues, however. The term vitritis is used to denote the presence of benign or malignant white blood cells in the vitreous.
Vitreous inflammation associated with infectious agents, particularly bacteria and fungi, is clinically referred to as infectious endophthalmitis. Bacterial endophthalmitis and fungal endophthalmitis (Fig 10-4) are characterized by neutrophilic infiltration of the vitreous that leads to liquefaction of the vitreous, with subsequent posterior vitreous detachment. Fungal endophthalmitis may have a granulomatous component. Severe inflammation may be accompanied by formation of fibrocellular membranes, typically in the retrolental space; these may exert traction on the peripheral retina.
The vitreous infiltrate in noninfectious uveitis is typically composed of chronic inflammatory cells, including T and B lymphocytes and histiocytes (Fig 10-5). See also BCSC Section 9, Uveitis and Ocular Inflammation.
Figure 10-4 Endophthalmitis. A, Gross photograph showing opacification and infiltration of the vitreous by inflammatory cells as a result of fungal endophthalmitis. B, Photomicrograph showing fungal organisms and cellular infiltration of the vitreous in endophthalmitis.
(Courtesy of Steffen Heegaard, MD.)
Figure 10-5 Noninfectious uveitis. Aggregates of epithelioid histiocytes (arrows) and scattered lymphocytes (arrowheads) in the vitreous base overlying the pigmented and nonpigmented ciliary epithelium (asterisks).
(Courtesy of Tatyana Milman, MD.)
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.