Abstract
Purpose :
The fluocinolone acetonide intravitreal implant has important benefits over systemic corticosteroids and immunosuppression for the treatment of non-infectious uveitis. Its benefits and risks have been well-documented, but recent clinical encounters have potentially revealed a new adverse effect of the implant: surgically induced corneal astigmatism. The purpose of this research is to identify and quantify the degree of corneal astigmatism induced by fluocinolone acetonide intravitreal implantation.
Methods :
This was a small retrospective cohort study of 7 patients (8 eyes) that underwent surgical implantation of the fluocinolone acetonide device in the last 10 years. Pre- and post-operative corneal astigmatism values were compared using corneal topographic or keratometric studies that were obtained as part of routine care. For mathematical and statistical comparison, astigmatic magnitudes and axes were converted into power vectors representing both with-the-rule/against-the-rule (WTR/ATR) and oblique components (J0 and J45, respectively). A third power vector, JFA, calculated the component of corneal steepening in the axis of the implant, assuming standard inferotemporal placement (225°/45° in the right eye and 315°/135° in the left eye).
Results :
The mean pre-operative right eye corneal astigmatism was 0.81 D at 51°, while the mean post-operative astigmatism was 1.3 D at 45°. The mean pre-operative left eye corneal astigmatism was 2.9 D at 96°, while the mean post-operative astigmatism was 4.6 D at 103°. JFA, the component of corneal steepening in the axis of the implant, increased perioperatively by an average magnitude across all eyes of 0.60 (P = 0.21). Secondary analysis revealed a non-statistically significant decrease in corneal power (0.8 D, P = 0.06) and increase in astigmatic magnitude (1.7 D, P = 0.08). Of note, there were two outliers in the group that had perioperative cylinder changes of 6.3 D and 4.0 D.
Conclusions :
While this study was limited statistically by small sample size, the results still showed notable perioperative corneal changes. It remains to be seen if the eyes with more drastic changes were simply outliers, or if expansion of the sample size will eventually reveal real, statistically significant effects of the surgery on corneal astigmatism. The conclusion of this research may ultimately describe a previously uncharacterized adverse effect of the fluocinolone acetonide implant.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.