Long-Term Implications of Untreated Demodex Blepharitis
Dr Starr addresses long-term consequences associated with nontreatment of Demodex blepharitis.
Christopher Starr, M.D., FACS: Demodex blepharitis can lead to a lot of long-term ocular health issues and, in very rare cases, potential blindness. (That) is one of those extreme headline-grabbing words — blindness. You can make the argument that that it’s rare, but a potentially real risk. Blepharitis is a term that gets thrown around very liberally among eye care providers. All blepharitis really means is Latin for inflammation of the eyelids, which is very nonspecific. Anterior blepharitis, posterior blepharitis are two ways that we split it, and Demodex blepharitis is probably the most common cause of anterior blepharitis. And there are studies that actually show that. That’s usually due to Demodex folliculorum. Then there’s posterior blepharitis, which is often what we would call meibomian gland dysfunction (MGD). There’s a form of Demodex that’s also related to that, and that’s Demodex brevis. Both of these forms of blepharitis can lead to long-term ocular health issues. We talked about chalazion and hordeolum, evaporative dry eye from MGD, loss of eyelashes and all of the ramifications of losing eyelashes and what that does to the ocular surface as well as the vulnerability of the ocular surface when you lose your eyelashes. In rare cases, that can all lead to preseptal or orbital cellulitis, where the eyelids get very infected, and that infection can spread to the back of the eye.
When there is blepharitis from Demodex — really, any form of blepharitis, but in this case Demodex, and the chronic inflammation that is associated with inflammation of the eyelids — well, that can also lead to ocular surface issues like pterygium or pinguecula. I’ve seen punctal stenosis in patients with excessive epiphora or tearing from that punctal stenosis from the inflammation of the ocular surface, and then other things like (staphylococcal) marginal keratitis, which we often associate with bacterial blepharitis, but when there’s Demodex there’s usually bacteria, too, and these things go hand in hand. So you get this vicious cycle and circle of inflammation of the ocular surface, which then leads to these other things. We talked about blindness, and I would make the argument that the risk of blindness can be very real. I would say that’s mostly in the area of intraocular surgery…. I’ve worked very hard on a publication with the ASCRS (American Society of Cataract and Refractive Surgery) cornea clinical committee that we published a few years ago, where we looked at the effect of the ocular surface on cataract surgery and the risks involved with ocular surface disease, including blepharitis and Demodex blepharitis, and the implications with cataract surgery in particular. But all forms of ocular surgery pertain.
We know that when there’s Demodex blepharitis, there is often bacterial overload as well. And that bacteria generally tends to be the (staphylococcal) and (streptococcal) gram-positive bacteria. Those are the same bacteria that lead to one of the most horrific complications of cataract surgery, which is endophthalmitis. If you see Demodex blepharitis, anterior blepharitis or collarettes prior to surgery, you have a pretty good idea that there’s an extra load of bacteria on those lids. And it behooves you as the surgeon to reverse that, to treat it aggressively prior to not only finalizing your ocular surgery measurements, but certainly before making any incisions and doing the surgery itself. God forbid endophthalmitis occurs after surgery from bacteria, and usually it’s not Demodex but rather it’s the bacteria that go hand in hand with Demodex that causes the infection. But yes, in a lot of those cases, probably the majority of (patients in those) cases do end up legally blind. We have to do everything we can to prevent that from happening.
