Influence of Elevated Intraocular Pressure on the Posterior Chamber–Anterior Hyaloid Membrane Barrier During Cataract Operations

Abstract

To investigate the influence of elevated intraocular pressure on the posterior chamber-anterior hyaloid membrane (PC-AHM) barrier during cataract operations in ex vivo porcine eyes. Methods: A pressure transducer was connected to porcine eye anterior chambers (ACs). In experiment 1, ACs were perfused for 20 seconds with balanced salt solution containing 1.0-µm fluorescein beads (10 eyes per bottle height: 45, 85, 145, and 285 cm). In experiment 2, 5 ophthalmic viscosurgical devices with different molecular weights and sodium hyaluronate concentrations were infused into the ACs (20 eyes per ophthalmic viscosurgical device). After continuous curvilinear capsulorrhexis, hydrodissection was performed. After both experiments, PC-AHM barrier staining was evaluated through the Miyake-Apple view. Results: Types of fluorescein staining patterns were classified as AC, zonule of Zinn, AHM, AHM tear, and ruptured capsule. In experiment 1, plateau intraocular pressure and staining type were positively correlated (Spearman rank correlation; r=0.703, P Ͻ.001). In experiment 2, mean peak intraocular pressure was significantly greater in the ruptured capsule-type eyes than in the AC-, zonule of Zinn-, AHM (P Ͻ .001), or AHMtear-(P=.02) type eyes, as well as in the AHM-and AHMtear-type eyes compared with the AC and zonule of Zinn type eyes (P Ͻ .001). Intraocular pressure was significantly higher in eyes infused with ophthalmic viscosurgical devices with a higher molecular weight or sodium hyaluronate concentration (P Ͻ.05). Conclusions: Stress on the PC-AHM barrier increases as intraocular pressure increases. Ophthalmic viscosurgical devices with a higher molecular weight or sodium hyaluronate concentration might induce increased IOP during cataract operations. Clinical Relevance: To maintain normal PC-AHM barrier function, excessive intraocular pressure should be avoided during cataract operations.

New side-view imaging technique for observing posterior chamber structures during cataract surgery in porcine eyes

“…This method is particularly useful for tracing the flow of irrigation fluids during surgical procedures. We have demonstrated that as the IOP increases, the posterior chamber-anterior hyaloid membrane barrier will undergo an elevation of pressure [5]. We confirmed that the fluorescein beads could be trapped by the dense network of zonular fibers during standard PEA (Additional file 2, Normal), indicating that the zonular fibers may act as an important barrier for the invasion of bacteria from entering the vitreous cavity.…”

“…This was possible because the BSS irrigation fluid contained 1.0-μm fluorescein beads as described [5]. As shown in the first part of this video file, the fluorescein beads can be seen to be trapped in the zonular fibers (Additional file 2, Normal).…”

“…We have reported on the benefits of using fluorescein beads in the irrigation solution during surgery [5]. The size of fluorescein beads is 1.0-μm in diameter, which is similar to that of bacteria.…”

“…The IOP of the operated eye was monitored continuously as described in detail [5]. In brief, a 2.4-mm corneal incision was made 1.5 mm central to the limbus at the 9-o’clock position.…”

Fluid dynamics and intraocular pressure using venturi phacoemulsification machine in dogs ex vivo

“…Phacodynamics has been reported as one of the important contributing factors to postoperative complications following phacoemulsification . To improve the success rate of phacoemulsification, the surgeon must understand the parameters of bottle height (BH), ultrasound energy, vacuum, and flow.…”