OBJECTIVES:
To determine the effects of intraocular pressure (IOP) and needle diameter on the amount of reflux after intravitreous bevacizumab injection.
METHODS:
Prospective randomized interventional study.
Twelve New Zealand white rabbits weighing approximately 2.5 to 3.5 kg each were randomized 1:1 to group 1 or group 2. Bevacizumab stained with trypan blue was used for intravitreous injection.
To lower the IOP, eyes in group 2 underwent anterior chamber paracentesis before intravitreous injection.
Two eyes in each group were injected using 27-, 30-, or 32-gauge needles.
If a subconjunctival bleb formed after intravitreous injection, its diameter was measured using a caliper.
RESULTS:
The median IOP in group 1 was 17.5 mm Hg. Eyes injected using 27-gauge and 30-gauge needles showed stained subconjunctival blebs with median sizes of 3 mm and 1.7 mm, respectively; eyes injected using 32-gauge needles showed no subconjunctival bleb formation.
The median IOP in group 2 was 10.3 mm Hg. Eyes injected using 27-gauge needles showed stained subconjunctival blebs with a median size of 0.7 mm, and eyes injected using 30-gauge and 32-gauge needles showed no subconjunctival bleb formation.
CONCLUSION:
Decreasing the IOP before intravitreous injection and using a smaller-gauge needle reduce the risk of drug reflux after intravitreous bevacizumab injection. CLINICAL
RELEVANCE:
Intravitreous injection is an increasingly common route of drug delivery to treat ocular diseases.
Techniques that maximize bioavailability are examined in this study.
2010-07-13
Eng.
Centro de Cirugía Oftalmológica, Universidad Central de Venezuela, Caracas, Venezuela.
Arch Ophthalmol. 2010 Jul;128(7):884-7
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