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Jocelyn G Lam, Ian Luttrell, Kasra Rezaei, Jennifer R Chao, Yewlin Chee, Leona Ding, Joanne C Wen; Measurement of ocular rigidity in patients undergoing intravitreal anti-VEGF injections. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3137.
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Studies have suggested that ocular rigidity (OR) may play a role in the biomechanics and pathogenesis of glaucoma. However, the effect of ocular rigidity is not well understood and its utility remains limited in current clinical practice. Anti-VEGF injections are known to cause a transient elevation in intraocular pressure (IOP) due to the limited compliance of the eye. Whether these repeated IOP elevations lead to changes in OR is unknown. We measured OR in patients undergoing anti-VEGF injections and other variables to determine whether any correlated with an increased post-injection IOP elevation.
We conducted a pilot study of patients who underwent intravitreal anti-VEGF injection. Patients with a history of glaucoma, ocular hypertension, current use of IOP lowering medications, and ocular surgery other than cataract extraction were excluded. Patients undergoing bilateral injections were also excluded. Baseline characteristics, axial length, pachymetry, and corneal hysteresis values were recorded. The coefficients of ocular rigidity values were obtained in injected and fellow non-injected eyes via Schiøtz tonometry and use of a standard conversion table.
Nineteen eligible subjects were included in the analysis. Mean age was 64.1 ± 13.8 years, 47% (9/19) were female, 53% (10/19) had a diagnosis of diabetic macular edema and 74% of injected medication (14/19) was aflibercept. Range of total injections was 1-46 (mean = 11). Post-injection IOP was significantly increased compared to baseline IOP following injection of anti-VEGF (mean change in IOP = 29.0 ± 9.5 mmHg; p<0.001). No correlation was found between the total number of injections and the coefficient of OR (r = -0.284; p=0.25). Increasing corneal hysteresis significantly correlated with a larger change in IOP following intravitreal injection (r = 0.62, p = 0.04), while coefficient of OR, axial length and corneal thickness did not.
Intravitreal injection of anti-VEGF compound leads to a significant transient rise in IOP following injection. The coefficient of OR was not significantly correlated with total number of anti-VEGF injections. However, increasing corneal hysteresis was correlated with increased change in post-injection IOP.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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