Abstract
Purpose :
Hydrogels containing polyacrylic acid polymers have been increasingly used to maintain corneal clarity during ophthalmic surgical procedures. We recently reported a series of patients who developed necrotizing granulomatous inflammation associated with GenTeal gel use during vitreoretinal surgery. We suspect the cause of this inflammation is carbopol 980, a high molecular weight, crosslinked polyacrylic polymer used as a thickener, and our study seeks to further investigate this potential link.
Methods :
Eight adult wild-type Dutch belted rabbits (n = 16 eyes) were exposed to a single 0.25cc subconjunctival injection in each eye of one of the following: hydroxypropyl methylcellulose (HPMC) 0.3% with carbopol 980 (GenTeal gel, n = 4), HPMC 0.3% (GenTeal drops, n = 3), HPMC 2% (Improvue, n = 3), carbopol 980 powder in balanced salt solution (BSS) (n = 3), or BSS (negative control, n = 3). All eyes were photographed and graded for subconjunctival inflammation at month 1 and 2 post-exposure. A survival biopsy was performed on 4 eyes of 2 rabbits at one month, and another rabbit was sacrificed for histopathologic analysis at 2 months.
Results :
Subconjunctival inflammation with vascular injection was noted at month 1 in 100% of eyes exposed to HPMC 0.3% with carbopol 980 (4/4) and carbopol 980 in BSS (3/3). Subconjunctival yellow lesions were evident in each of these 7 eyes at month 2. There was no clinically evident inflammation or yellow lesions in the 9 eyes receiving injections lacking carbopol 980: HPMC 0.3% (0/3), HPMC 2% (0/3), or BSS (0/3), (p<0.0001, Fisher’s exact test). Histopathology of 4 biopsies performed at 1 month revealed 2 with submucosal collections of histiocytes (HPMC 0.3% + carbopol 980, carbopol 980 in BSS) and 2 without abnormalities (HPMC 2%, BSS). Two eyes biopsied at month 2 revealed one biopsy without abnormalities (HPMC 0.3%) and another with submucosal histiocytes (HPMC 0.3% + carbopol 980).
Conclusions :
Subconjunctival exposure to carbopol 980 is associated with the development of chronic inflammation characterized by histiocytic infiltration. Similarly-formulated agents lacking carbopol 980 do not elicit a clinical or histopathologic inflammatory reaction. Based on these results, subconjunctival exposure to carbopol 980 should be avoided, and caution should be exercised when considering surgical use of any agents containing polyacrylic acid polymers.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.