Abstract
Purpose: :
Performing an intravitreal Lucentis injection (IVL) increases the intraocular volume by 0.05ml. Most eyes can tolerate this change in volume, however certain eyes may be predisposed to significant post-IVL intraocular pressure (IOP) spike which may potentially cause an adverse consequence in certain susceptible eyes. The aim of the following study is to investigate the influence of IVL on the magnitude of IOP immediately post-injection and its relationship to axial length.
Methods: :
IOP measurements were taken pre-IVL, immediately after and at 30 minutes post-IVL on 36 consecutive eyes who presented to our department. Axial length (AL) measurements were taken on all eyes prior to IVL of the standard volume of 0.05ml. All three IOP measurements were taken with a Tonopen, and axial lengths were measured using IOLmaster. Eyes were separated into two groups: short vs. normal-long axial length (AL<23mm vs. AL>23mm). Difference between two group means was tested for statistical significance using student t-test.
Results: :
Immediately after IVL, measured IOP was elevated by a mean of 26.2±8.33 mmHg compared with pre-IVL IOP (p<0.001). AL measurements ranged from 20.75 to 31.37mm. Eyes with shorter AL (AL<23mm) had significantly higher IOP immediately after IVL and at 30 minutes (p<0.05) when compared to other groups (AL>23mm). 12 of the shorter axial length eyes developed post-IVL IOP spikes of greater than 30mmHg.
Conclusions: :
Although significant spikes in IOP following IVL are uncommon, the clinician may want to avoid this adverse event in certain eyes where recurring IOP spikes may be damaging to the optic nerve, such as patients with advanced glaucoma, and eyes with compromised ocular blood flow. Our results show that IOP spikes were found immediately after injection in all eyes, with greatest magnitude found in those eyes of short axial length. The use of ocular decompressive devices (e.g. Honan Balloon) or pharmacolgical agents (e.g. Guttae. Iopidine 1%) to lower IOP pre-IVL might be prudent in order not to impair perfusion in those eyes and further enhance the safety of this procedure of drug delivery.
Keywords: intraocular pressure • injection