Six steps to more comfortable intravitreal injections

A patient information leaflet on intravitreal injections is available here.

Many patients are apprehensive about having intravitreal injections. There is no doubt about the benefits of these injections. Previously blinding conditions are no longer vision-threatening with injection therapy. However, having a needle in the eye is something other than what one would look forward to. Some people find these injections so unpleasant that they will risk losing their vision by having further injections.

However, injections to the eye do not have to be painful, and here I will discuss six simple modifications to more comfortable intravitreal injections.

Consider an alternative to iodine antiseptic in intravitreal injections

In many patients, the injection is tolerable, but they find their eyes very painful 24 to 48 hours afterwards. This is commonly due to corneal disturbance, and iodine antiseptic is a common cause. However, iodine is generally considered the best regarding anti-microbial activity, and not all patients are sensitive to iodine.

So in patients with sensitive cornea, switching from iodine to chlorhexidine antiseptic is the way to avoid post-injection pain.

Look after the cornea after intravitreal injections

No matter how good your technique is, there will always be some compromise in the corneal epithelium after intravitreal injection. One can easily see this by examining a patient immediately after intravitreal injection, and there will be at least some punctate epithelium erosion. The patient needs to use frequent topical lubricants at least once every hour for the first 24 hours after injection. In more sensitive patients, an eye pad to keep the injected eye shut for 24 hours can be beneficial (although it is impossible to do this in bilateral injections!).

Some physicians advocate using topical steroids +/- antibiotics post-injection, treating corneal epitheliopathy as a mild chemical injury. I have yet to try this but will consider steroid therapy in sensitive patients.

Use plenty of anaesthetics

This may seem like a no-brainer, but the eye needs to be adequately numbed before performing the procedure. The nerve fibres on the conjunctiva and cornea are susceptible to topical anaesthetics, and that is why cataract surgery through a clear corneal incision can be performed with a few drops of tetracaine. Regarding intravitreal injections, the needle will transverse through the conjunctiva, the episclera and the sclera, and the pain fibres below the conjunctiva are more challenging to block.

I placed a cotton bud soaked in topical tetracaine on the injection site for at least 60 seconds to numb the area before the injection completely. This is usually adequate to make the procedure painless. With this technique, one common issue I see is that, as there is no surface marking on the eye showing the numbed area when performing the intravitreal injection, the needle can be mistakenly placed in an area of the eye which has not been numbed, resulting in significant pain. All it takes to solve this is to have a clear mental note of the numbed area (using conjunctival vessels as landmarks) and be careful when placing the intravitreal injection.

Some patients cannot be numbed adequately with topical anaesthetics. I have a low threshold in administering subconjunctival 1% xylocaine, which effectively achieves a complete blockade of the pain fibres. Almost all patients receiving intravitreal injections under subconjunctival anaesthetics report no pain or discomfort during the procedure.

Move the injection site for repeated intravitreal injections

Usually, intravitreal injections are performed in the superotemporal quadrant of the eye. With repeated injections, there can be localised fibrosis of the sclera, making the intravitreal injection more complicated (as the needle will have trouble perforating the fibrosed tissue). In some patients, recalcitrant pain fibres can be in that region, making the injection painful despite subconjunctival anaesthetics. In these cases, simply moving the injection site to superior or superonasal will dramatically reduce the amount of pain during the intravitreal injection.

Avoid subconjunctival haemorrhage at the time of an intravitreal injection

Although subconjunctival haemorrhages are harmless, this will no doubt add to anxiety with the injections and make the eye more uncomfortable. Most subconjunctival haemorrhages occur not when the needle enters the eye but as the needle withdraws from the eye, causing the conjunctiva to be tented up. When removing the needle, this can be easily avoided by using the eye marker to hold the conjunctiva down.

Manage the anxiety associated with intravitreal injections

Patient psychology significantly affects the amount of pain they experience during intravitreal injections. One interesting observation is that most patients do not have a lot of pain during their first intravitreal injection, as they do not know what to expect, and the injection is over before they realise it. However, by their second intravitreal injection, they are hyper-vigilant for pain and much more likely to have a less than pleasant experience.

Pain is much more common and severe if a patient expects the intravitreal injection procedure to be painful. The first 1-2 intravitreal injections are crucial in setting the expectation - you want to make sure these are as comfortable as possible, and this will make the subsequent injections much easier. Otherwise, you can help to calm the patient by listening and explaining before and during the procedure for a smoother outcome. I always have an assistant with me to hold the patient's hand to give reassurance during the injection.

So, here are my six steps to a more comfortable intravitreal injection

I hope you find this article useful, and let me know if you have other techniques to make intravitreal injections more pleasant. These injections are vital to help maintain and improve vision, and most patients will need repeated injections. Making these injections as comfortable as possible is key to improving adherence to the treatment schedule and, ultimately, visual outcomes.

About Dr Leo Sheck

Dr Sheck is a RANZCO-qualified, internationally trained ophthalmologist. He combined his initial training in New Zealand with a two-year advanced fellowship in Moorfield Eye Hospital, London. He also holds a Doctorate in Ocular Genetics from the University of Auckland and a Master of Business Administration from the University of Cambridge. He specialises in medical retina diseases (injection therapy), cataract surgery, ocular genetics, uveitis and electrodiagnostics.