If you’ve done your research on fillers, you’ve probably come across rare but serious side effects like skin necrosis, scarring, and even more devastating, blindness. Yes, the odds of them happening are low (about 50 cases a year worldwide), but the risk still lies. In a recent literature review on the implications of filler injections, out of 98 cases of visual impairment, 65 had unilateral vision loss and only 2 cases were reversible.
This indeed sounds very frightening. Don’t worry, I’m not here to scare you against getting fillers; in fact it’s the opposite of what I’m trying to do. In this article, I will explain the mechanics of how fillers can cause blindness and how to reduce your risk.
In today’s age, patients get to choose from a plethora of dermal fillers for facial aesthetic correction. These fillers range from hyaluronic acid, calcium hydroxylapatite, polycaprolactone to autologous fat. Of these, hyaluronic acid is the most widely used due to its enviable water-attracting properties and longevity. At my clinic, I use brands like Juvederm, Restylane and Radiesse. I rarely see autologous fat injections offered in most aesthetic clinics in Singapore; but if you’re curious, fat injections basically use fat harvested from the patient’s own body to enhance facial fullness or fill creases. Autologous fat filler procedures are more extensive than ready-made soft-tissue fillers as fat must first be drafted off.
We have very small blood vessels or arteries surrounding our forehead and eye area. These blood vessels supply blood to the area. When fillers are not injected properly, this can lead to a blockage of a blood vessel that supplies blood to the eye, resulting in blindness. This condition is also known as central retinal artery occlusion.
It’s thought that there are a few factors that contribute to blindness.
Site of injection
Researchers have found that injection sites that hold the highest risk are the glabellar (38.8%), nasal region (25.5%), nasolabial fold (13.3%) and the forehead (12.2%). The glabellar region has the highest risk because any deep injection on the periosteum stand a chance of entering the supratrochlear artery and supraorbital artery, whereas the nasal dorsum and nasolabial folds are nearer the facial artery and angular artery.
Type of filler
So far, about 47% of cases of filler-induced blindness are attributed to autologous fat injections. The rest of the cases go to different soft-tissue fillers. This is thought to be because of the variation in the size of the fat globules, which can differ in size. Variation in size affects the blockage of small, medium and large-sized arteries. Since regular soft-tissue fillers have smaller particles that are more constant in size, they will therefore potentially only block certain smaller-sized arteries. Even if these arteries are blocked, they may still be able to deliver blood with oxygen to the eye and so the prognosis may not be as bad.
Speed and pressure of injection
To any doctor, his most important body part is probably his hands because the hands are what holds and controls the instrument. When it comes to injecting a filler, it’s been deduced in the literature that the speed and pressure of the injection has influence on the flow of the filler within the vessel. In many cases of retinal necrosis, it was found that the filler was injected with too much pressure.
1. Avoid the arteries
This may seem obvious, but all clinicians providing filler injections should possess an in-depth and working knowledge of facial and vascular anatomy. Do extensive research on the doctor you’re considering — do they have the necessary board qualifications? Do they have an excellent track record of clinical practice?
2. Inject to the correct depth and plane
If a mole that wasn’t once raised is now raised, you should have it checked out by a doctor. The same goes for moles that shrink, change colour, itch or bleed. Essentially, moles that change in appearance over time are usually warning signs.
3. Have a crisis strategy in place
No procedure is completely immune to error. Blindness from fillers is very rare, but should central retinal artery occlusion take place, patients only have a retinal survival time of 60-90 minutes. During this limited window, you must be referred immediately to an ophthalmologist to reverse the effect.
With all that’s said, I hope you understand that every procedure comes with its risks; but they can be reduced with a responsible and competent doctor. Ultimately, it’s the doctor’s responsibility to ensure that every procedure goes smoothly.