The relationship between the intraocular position of dexamethasone intravitreal implant and post-injection intraocular pressure elevation

Objective To investigate the relationship between the implantation position of dexamethasone intravitreal implant (DEX-I) and post-injection intraocular pressure (IOP) elevation. Methods This retrospective study included 324 patients (332 eyes) who received at least one DEX-I injection between June 2020 and June 2024, with a follow-up period of at least 3 months. Patient demographics, diagnoses, and DEX-I implantation positions were recorded. The correlation between implantation position and post-injection IOP elevation was analyzed. IOP elevation was defined as an IOP greater than 25 mmHg and/or an increase of 10 mmHg from baseline. DEX-I implantation positions were defined as follows: P1: implant located in the vitreous near the ciliary body, anterior to the ora serrata (with or without ciliary body contact); P2: implant located in the vitreous from the ora serrata to the pre-equatorial region; P3: implant located in the post-equatorial vitreous. The equator was defined by the vortex veins. Results During the follow-up period, 68 eyes (20.48%) experienced IOP elevation. Compared to P2 and P3, the P1 implantation position was significantly associated with a higher incidence of IOP elevation ( p < 0.001) and was positively correlated with early IOP elevation (within 15 days post-injection) ( r = 0.761; p < 0.001). Conclusion The P1 implantation is positively correlated with IOP elevation, particularly with early IOP elevation.