47 EyeWorld Asia-Pacific | December 2024 ASIA-PACIFIC PERSPECTIVES Hisaharu Suzuki, MD Zengyo Suzuki Eye Clinic, 1-22-11 Zengyo, Fujisawa City, Kanagawa, Japan s5054@nms.ac.jp As Dr. Price has stated, the most important aspect of cataract surgery in cases involving corneal endothelial cell depletion is the use of viscoelastic materials, with dispersive viscoelastic agents being essential. Dispersive viscoelastics are applied first, followed by viscoadaptive viscoelastics. However, it is important to create a working space after discharging a certain amount of viscoadaptive viscoelastics with BSS during hydrodissection. This is because vigorous hydrodissection, without allowing any pressure to escape, may cause rupture of the posterior capsule. Viscoelastics should be maintained in the anterior chamber while the nucleus is being processed. Therefore, the direction of irrigation must be carefully considered. By directing the irrigation toward the lens capsule, it is possible to prevent the flow of irrigation toward the corneal endothelium, allowing the viscoelastic material to remain on the endothelial side. The dispersive coating on the corneal endothelium protects it from free radicals and other invasive factors. Moreover, the underlying viscoadaptive viscoelastics prevent physical invasion, as the nucleus is carried by perfusion and impinges on the corneal endothelium. In addition, postoperative corneal endothelial invasion can be assessed by observing the density of corneal endothelial cells using specular microscopy. It is recommended to evaluate the endothelial cell density in various parts across the cornea (up, down, left, and right), as the corneal endothelium can be relocated. Furthermore, corneal volume reflects a wider range of corneal endothelial functions than corneal thickness. This volume can be measured across a diameter of 3 or 10 mm.1 The central optical area should be evaluated at 3 mm, and 10 mm if edema is present around the incision wound. It can be measured using the Pentacam or anterior-segment optical coherence tomography. Previously, we proposed the Volume Stress Index (VSI), which evaluates corneal endothelial function by combining corneal volume and corneal endothelial cell count.2 VSI is a useful index for evaluating corneal endothelial function, as it represents the amount of work corneal endothelial cells must do to improve corneal edema over time. CORNEA Editors’ note: Dr. Hisaharu Suzuki disclosed no relevant financial interests. Reference: 1. Suzuki H, et al. Phacoemulsification associated corneal damage evaluated by corneal volume. Am J Ophthalmol. 2006 Sep;142(3):525-8. 2. Suzuki H, et al. Functional evaluation of corneal endothelium by combined measurement of corneal volume alteration and cell density after phacoemulsification. J Cataract Refract Surg. 2007 Dec;33(12):2077-82.
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