Sampling Aqueous Humor: Anterior Segment Anatomy, Anesthetic and Surgical Technique, and Rates of Yield

Abstract

Purpose: To evaluate anterior segment anatomy and anesthetic and surgical techniques with respect to the amount of aqueous humor (AH) that can be sampled out of the anterior chamber (AC) at the beginning of standard cataract removal procedures (phacoemulsification). Methods: In a prospective survey, volumes of sampled AH from 123 eyes (110 patients) were analyzed in regard to AC anatomy (anterior chamber depth, ACD) and different anesthetic techniques (local and general anesthesia). Results: 107 eyes (87%) were included into our analysis, and 16 eyes (13%) had to be excluded due to failure of AH collection. We found a significant positive association between ACD and obtained AH volume (p = 0.007). In general anesthesia, a strong trend to acquire more AH in comparison to local anesthesia was apparent, but statistical significance failed (p = 0.167). Different anesthetic techniques seem to have no significant influence on ACD (p = 0.169). No training curve for the individual surgeon was obtained. No complications were observed. Conclusion: When AH sampling is performed in eyes with a deep AC and when the procedure is performed under general anesthesia, more AH can be aspirated.

Intravitreal Functional Plasminogen Is Elevated in Central Retinal Vein Occlusion

“…No adverse events or serious side effects occurred and sampling vitreous fluids with either technique was revealed to be a safe procedure. Previous studies confirm those observations [12,13,14] although serious complications may occur and sampling aqueous humor was declared as a safer way to collect intraocular specimens [15,16]. Nevertheless, we decided to analyze vitreous samples instead of aqueous humor samples because intraocular plasminogen activity within the eye is low [17] and there is a substantial dilution effect between the anterior and posterior segments of the eye [11,18,19].…”

Fibrinolysis in normal vitreous liquid

“…No adverse events or serious side effects occurred and sampling vitreous fluid at the start of a standard 23-gauge three-port pars plana vitrectomy revealed to be a well tolerated procedure. Previous studies confirm these observations [5,[12][13][14], although serious complications may occur and sampling aqueous humour was declared as a more well tolerated way to collect intraocular specimen [8,15]. Nevertheless, we decided to analyse vitreous samples instead of aqueous humour samples (AHS) because intraocular fibrinolysis in healthy eyes is assumed to be low [16] and there is a substantial dilution effect between the anterior and posterior segment of the eye [17][18][19].…”

Use of Ella ® to Facilitate drug Quantification and Antidrug Antibody Detection in Preclinical Studies

“…In contrast, an increased dynamic range would be beneficial because samples would not require high dilutions to be in the assay range. In addition, lower sample consumption of the Ella platform (2.5 vs 25 μl in ELISA) would reduce the difference in sensitivity for samples with limited availability such as mouse samples or rare sample matrices like eye, synovial or cerebrospinal fluids [1][2][3][4]. For example, if only 2.5 μl is available, the sensitivity of the Ella assay would be still 15 ng/ml, whereas the sensitivity of ELISA would be decreased to 19 ng/ml.…”