Abstract
PurposeTo measure needle insertion force and change in intraocular pressure (IOP) in real-time during intravitreal injection (IVI). The effects of needle size, insertion speed, and injection rate to IOP change were investigated.MethodsNeedle insertion and fluid injection were performed on 90 porcine eyeballs using an automatic IVI device. The IVI conditions were divided according to needle sizes of 27-gauge (G), 30G, and 33G; insertion speeds of 1, 2, and 5 mm/s; and injection rates of 0.01, 0.02, and 0.05 mL/s. Insertion force and IOP were measured in real-time using a force sensor and a pressure transducer.ResultsThe peak IOP was observed when the needle penetrated the sclera; the average IOP elevation was 96.3, 67.1, and 59.4 mmHg for 27G, 30G, and 33G needles, respectively. An increase in insertion speed caused IOP elevation at the moment of penetration, but this effect was reduced as needle size decreased: 109.8–85.9 mmHg in 27G for 5–1 mm/s (p = 0.0149) and 61.8–60.7 mmHg in 33G for 5–1 mm/s (p = 0.8979). Injection speed was also related to IOP elevation during the stage of drug injection: 16.65 and 11.78 mmHg for injection rates of 0.05 and 0.01 mL/s (p < 0.001).ConclusionThe presented data offers an understanding of IOP changes during each step of IVI. Slow needle insertion can reduce IOP elevation when using a 27G needle. Further, the injection rate must be kept low to avoid IOP elevations during the injection stage.
Highlights
Intravitreal injections (IVIs) have been widely used for the direct delivery of anti-vascular endothelial growth factor (VEGF) or steroids into the eye
An increase in insertion speed caused intraocular pressure (IOP) elevation at the moment of penetration, but this effect was reduced as needle size decreased: 109.8–85.9 mmHg in 27G for 5–1 mm/s (p = 0.0149) and 61.8–60.7 mmHg in 33G for 5–1 mm/s (p = 0.8979)
Injection speed was related to IOP elevation during the stage of drug injection: 16.65 and 11.78 mmHg for injection rates of 0.05 and 0.01 mL/s (p < 0.001)
Summary
Intravitreal injections (IVIs) have been widely used for the direct delivery of anti-vascular endothelial growth factor (VEGF) or steroids into the eye. The IVI procedure involves the insertion of a small gauge needle (27-gauge [G] to 33G) and the injection of 0.05 mL of fluid. Needle insertion and drug injection can elevate the intraocular pressure (IOP) in both the short term and the long term; this constitutes the main complication of IVI. IOP peaks and IOP fluctuations can be especially harmful to patients who already have glaucoma or retinal diseases [1,2,3]. For this reason, several studies have measured IOP immediately after IVI (postIOP) to confirm the short-term IOP changes caused by needles of different sizes [4, 5]. Because penetration force and IOP elevation are related to pain, penetration force and pain scores have been measured for different needle sizes [6,7,8,9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
