Accuracy and precision of intraocular injection volume.
OBJECTIVE
To assess the accuracy and precision of methods in clinical use for intraocular drug injection.


METHODS
Experimental laboratory investigation.


METHODS
A total of 800 injections were performed using 20 different 1-ml syringes at intended volumes of 0.10 ml and 0.05 ml. The volume of each injection was calculated from mass of water delivered onto an analytic balance.


RESULTS
The mean measured volume delivered was less than the intended volume for every syringe (P <.001 for each syringe at each volume). A total of 7% and 22% of injections differed by 20% or more from the intended volumes of 0.10 ml and 0.05 ml, respectively. Overdelivery of volume was uncommon.


CONCLUSIONS
Clinically relevant materials and methods used for intraocular injection of drugs systematically underdelivered the intended volume.
Raju
Jhansi R
JR
Department of Ophthalmology, Northwestern University Medical School, Chicago, Illinois 60611, USA.
Weinberg
David V
DV
D007267:Injections / Q000592:standards*; D009885:Ophthalmology / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results; D013594:Syringes / Q000592:standards*; D014894:Weights and Measures / Q000592:standards*