Improving the safety profile of the technique using a guide
The intravitreal device can also help to standardise this procedure, which should lead to a reduction in complications, such as traumatic lens injury. The standard method requires the needle to be inserted perpendicularly through the sclera with the tip of the needle pointing towards the centre of the globe to avoid injury to the posterior lens.4
The injection site is marked using sterile ophthalmic callipers – usually 3.5 mm posterior to the limbus for an aphakic or pseudophakic eye or 4 mm posterior to the limbus for a phakic eye.5
The instrument is specifically designed to overcome these challenges through the addition of an arrow on the apex of the base plate to show the correct positioning at the limbus. A cylindrical chamber eliminates the possibility of over inserting the needle and subsequently causing retinal injury by only allowing 7-mm of a 13-mm/30-gauge needle to enter into the eye.
Meanwhile, with the base plate of the guide firmly in position, the guide allows the injection to be delivered at the correct distance from the limbus, 4mm, and at the correct perpendicular angle to the sclera (Figure 2).