Abstract
Abstract: :
Purpose: Uveitis seldom permits an etiologic diagnosis. Systemic studies are generally uninformative and uveitis classifications are mainly based on clinical or histopathologic appearances. Therapy is largely nonspecific and despite major advances in immunodiagnosis, uveitis still lacks access to effective laboratory analysis. Unlike most confined inflammations, there has been a general reluctance to analyze the aqueous humor that directly bathes inflamed and infected uveal tissues. The use of advanced immunologic, cytologic or PCR microassays has been constrained, and the full range of diagnostic information that an aqueous sample may contain remains unknown. Methods:Concerns about paracentesis have long centered on its trauma and the risk of inducing endophthalmitis. While the latter is preventable by careful asepsis, its trauma–inducing aspects are seldom addressed. Therefore, we analyzed conventional syringe–needle techniques to identify potential trauma sources; e.g. syringe size, plunger motion, dead space, needle length, puncture resistance, forceps fixation. A bulb pipet prototype minimizing these features was then compared during rabbit eye paracentesis (n=12). Total protein (TP) assays estimated aqueous barrier leakage. Tissue plasminogen activator (t–PA) release from sympathetic axons was also assayed. Pipet function was further evaluated during 15 human cataract extractions. Results: Rabbit eye syringe–needle TP levels were two–fold greater and had a six–fold wider SD than in pipet samples recovered from opposite eyes: (0.631 +/– 0.322 vs 0.325 +/– 0.050 mg/ml). Corresponding t–PA levels were 0.0049 +/– 0.032 vs 0.031 +/– 0.007. Syringe–needle taps required 45–60 seconds versus less than ten seconds for pipet use. Limbal puncture resistance was minimal with the one–handed pipet aspiration in both species. Conclusions: We conclude that paracentesis trauma effects and duration can be minimized by eliminating unneeded elements of current methods.
Keywords: uveitis–clinical/animal model • aqueous • trauma