Journal roundup: Scleral lenses
Hurray, a study about fogging!
What it really means for you and me, well, that’s another story, but at least they have heard THIS point loud and clear:
Midday fogging is a frequent complaint among scleral contact lens
…and are working on understanding it better so as (hopefully) to come up with better solutions. It seems those with fogging have lots and lots of leukocytes, which they collected by washing out lenses and eyes and counting them. They associated more leukocytes with a higher lens clearance. Seems to me I heard some debate about that at the GSLS conference recently. It was a fairly small study and hopefully there will be more. And I suspect we all know where they could find a lot of volunteers.
More: Identification of Leukocytes Associated With Midday Fogging in the Post-Lens Tear Film of Scleral Contact Lens Wearers. (Postnikoff et al, IOVS, January 2019.)
Household terms for all of us, I know….
No, this is not something you should know or will ever want to (me either, probably). It’s just an abstract (see link below) that tripped my thoughts.
I have biofilm on the brain a lot lately: That is, more or less invisible crud on scleral lenses… meaning lenses that look and feel reasonably clean but might be harboring bad stuff. It’s always tricky with anti-microbials, you want something that will super-lethal to the bad guys and super-gentle on your cornea if any ends up there. Now I don’t know if this particular study had implications for any solution that might be used on our kind of lenses at all (the study does not specify) - quite possibly they’re only looking at something they can add to a soft lens multipurpose solution right now.
But… some things in this study caught my eye that I believe are relevant to us:
The formation of bacterial biofilms on the surface of biomaterials is associated with increased antibiotic resistance.
I do NOT like the sound of that.
(C10)₂-KKKK-NH₂ exhibited stronger anti-biofilm properties… at relatively low concentrations…. Estimation of the eye irritation potential… suggests that the compound could be safely applied on the human eye. The results of performed experiments encourage further studies on… its potential application in the prophylaxis of contact lens-related eye infections.
Each type of contact lens has its uniquenesses, but sclerals are “more unique”, so to speak, than any of the others and may bear risks that we do not fully understand yet because we’re so early in the science of them that there just isn’t enough published data to know. So the more we can be doing to prevent infection - since these lenses are used primarily on diseased corneas - the better.
More: Antibacterial Activities of Lipopeptide (C10)₂-KKKK-NH₂ Applied Alone and in Combination with Lens Liquids to Fight Biofilms Formed on Polystyrene Surfaces and Contact Lenses. (Paduszynska et al, International Journal of Molecular Sciences, Jan 2019)
Pediatric use of PROSE in Stevens Johnson Syndrome
Here’s a good one for parents of kids with severely diseased corneas… It really just doesn’t get much worse than Stevens Johnson Syndrome, so to me, this study says that PROSE can do a lot for kids.Two thirds might not sound like overwhelming odds, but… that’s actually a lot of kids who had much better visual outcomes than they might have otherwise. Their mean follow-up period was more than five years, so the longer-term trajectory seems quite positive.
The study was a retrospective case series of 49 patients (!). I have to say it’s heartbreaking to know 19 of them got SJS from something as basic as an antibiotic. Yikes. And in 9 cases, the cause isn’t even known. What I’d really like to know, though, is for the 30% of kids that were not successful with PROSE, what was the reason?
More: Prosthetic Replacement of the Ocular Surface Ecosystem Treatment for Ocular Surface Disease in Pediatric Patients with Stevens-Johnson Syndrome. (Wang et al, American Journal of Ophthalmology, Jan 2019)