Intravitreal administration

[1] Intravitreal injections were proposed over a century ago however the number performed remained relatively low until the mid 2000s.

[1] The most common reason intravitreal injections are used is to administer anti-vascular endothelial growth factor (anti-VEGF) therapies to treat wet age related macular degeneration (AMD) and diabetic retinopathy.

Bevacizumab has not been FDA approved to treat wet AMD however in the US it is the first line anti-VEGF therapy for over half of ophthalmologists due to its efficacy and drastically lower cost.

All three of these therapies have vastly improved outcomes for sufferers who had limited treatment options prior to their invention but must be administered via intravitreal injection.

[5] Endophthalmitis, or a bacterial infection within the eye causing inflammation of the sclera, is one of the most severe complications due to intravitreal injections.

One clinical trial of ranibizumab for age-related macular degeneration administered intravitreally reported intraocular inflammation rates between 1.4% and 2.9%.

[6] Rhegmatogenous retinal detachment, when the retina breaks allowing vitreous fluid to leak into the subretinal space, resulting from intravitreal injection is rare, occurring at most in 0.67% of people.

[6] This fluid can cause sensory tissues to detach from the retina, thus losing their source of nutrition, and slowly killing the cells.

For example, anti-VEGF therapies must be injected monthly or bi-monthly for the rest of their lives in order to treat wet age related macular degeneration.

[10] Studies have shown an increased risk of sustained elevated intraocular pressure due to repeated intravitreal injections.

[11] Mount Sinai researchers have developed a method to measure retina damage from long term intravitreal injection using optimal coherence tomography angiography (OCTA).

The strong 2004 consensus that the pupil should be routinely dilated to examine the posterior segment of the eye post injection was dropped.

The new guidelines include hand washing and glove use consistent with the modern-day medical practice of universal precautions.

Since then new evidence has come to light showing that streptococcal species cause a disproportionate number of post intravitreal injection endophthalmitis cases compared to other forms of ocular surgery.

[20] The 2014 guidelines were updated to address these findings recommending both clinicians and patients wear face masks during the procedure.

This recommendation stemmed from new evidence showing that routine intravitreal administration of anti-VEGF therapies may increase intraocular pressure for a sustained time period.