Open-capsule intraocular lens to prevent posterior capsule opacification.

PURPOSE: To develop a single-piece open-capsule intraocular lens (IOL) that can be inserted through a small incision and that prevents posterior capsule opacification (PCO) by expanding the capsule and circulating aqueous humor into the capsular bag. SETTING: Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan. DESIGN: Experimental study. METHOD: Using the same hydrophobic acrylic material as the NY-60 IOL, a prototype open-capsule IOL was constructed. The IOL has a single optic and 2 haptics, with a 2.8 mm high spacer and holes through which aqueous humor circulates into the capsular bag by separating the anterior capsule from the posterior capsule and expanding the capsule. The open-capsule IOL or NY-60 (as a control group) was inserted in rabbit eyes. Posterior capsule opacification development was evaluated by measuring the thickness of the cell layer at the center of the posterior capsule on histopathologic specimens and statistically comparing the thickness between the open-capsule IOL group and control group. RESULTS: The open-capsule IOL could be inserted through a 3.2 mm corneal incision using a D cartridge. The mean thickness of the cell layer at the center of the posterior capsule was 4.78 µm ± 2.61 (SD) in the open-capsule IOL group and 101.14 ± 25.19 µm in the control group and was significantly smaller in the open-capsule IOL group. CONCLUSION: The prototype single-piece IOL could be implanted through a small incision and prevented PCO by expanding the lens capsule and circulating aqueous humor into the capsular bag.

The occhiolino (occ) mutant Zebrafish, a model for development of the optical function in the biological lens.

BACKGROUND: Zebrafish visual function depends on quality optics. An F3 screen for developmental mutations in the Zebrafish nervous system was conducted in wild-type (wt) AB Zebrafish exposed to 3 mM of N-ethyl-N-nitrosourea (ENU). RESULTS: Mutant offspring, identified in an F3 screen, were characterized by a small pupil, resulting from retinal hypertrophy or hyperplasia and a small lens. Deficits in visual function made feeding difficult after hatching at approximately 5-6 days postfertilization (dpf). Special feeding conditions were necessary for survival of the occhiolino (occ) mutants after 6 dpf. Optokinetic response (OKR) tests measured defects in visual function in the occ mutant, although electroretinograms (ERGs) were normal in the mutant and wt. Consistent with the ERGs, histology found normal retinal structure in the occ mutant and wt Zebrafish. However, lens development was abnormal. Multiphoton imaging of the developmental stages of live embryos confirmed the formation of a secondary mass of lens cells in the developing eye of the mutant Zebrafish at 3-4 dpf, and laminin immunohistochemistry indicated the lens capsule was thin and disorganized in the mutant Zebrafish. CONCLUSIONS: The occ Zebrafish is a novel disease model for visual defects associated with abnormal lens development. Developmental Dynamics 246:915-924, 2017. © 2017 Wiley Periodicals, Inc.

Influence of intraocular lens implantation on anterior capsule contraction and posterior capsule opacification.

PURPOSE: To evaluate whether and how intraocular lens (IOL) implantation influences the development of anterior capsule contraction and posterior capsule opacification (PCO). SETTING: Department of Ophthalmology, Dokkyo Medical University, Mibu, Tochigi, Japan. DESIGN: Experimental study. METHODS: Phacoemulsification was performed in 8-week-old white rabbits. A hydrophobic acrylate IOL (12.5 mm) (YA-60BBR) was implanted in 1 eye and no IOL was implanted in the fellow eye. Slitlamp microscopy and anterior segment analysis were performed to evaluate anterior capsule contraction after the surgery. Four weeks postoperatively, sections of the eyes were made, and the thickness of the proliferated lens epithelial cell (LEC) layer at the posterior capsule was measured to assess the PCO. In addition, LECs from white rabbits were cultured in medium containing 50% aqueous humor or in medium containing 50% saline to determine the influence of the aqueous humor on LECs and to compare the degree of LEC proliferation. RESULTS: Starting 2 weeks after surgery, anterior capsule contraction progressed more significantly in the IOL group than in the group without IOLs. Four weeks postoperatively, LEC thickness at the posterior capsule was significantly less in the group without IOLs than in the IOL group. In the culture study, LEC proliferation was more inhibited in the aqueous humor group than in the saline group. CONCLUSIONS: Progression of anterior capsule contraction and PCO is less likely in aphakic eyes than in IOL-implanted eyes. The mechanism of prevention may involve aqueous humor-induced inhibition of LEC proliferation.

Cell fate and differentiation of the developing ocular lens.

PURPOSE: Even though zebrafish development does not include the formation of a lens vesicle, the authors' hypothesis is that the processes of cell differentiation are similar in zebrafish and mammals and determine cell fates in the lens. METHODS: Two-photon live embryo imaging was used to follow individual fluorescently labeled cells in real-time from the placode stage at 16 hours postfertilization (hpf) until obvious morphologic differentiation into epithelium or fiber cells had occurred at approximately 28 hpf. Immunohistochemistry was used to label proliferating, differentiating, and apoptotic cells. RESULTS: Similar to the mammal, cells in the teleost peripheral lens placode migrated to the anterior lens mass and differentiated into an anterior epithelium. Cells in the central lens placode migrated to the posterior lens mass and differentiated into primary fiber cells. Anterior and posterior polarization in the zebrafish lens mass was similar to mammalian lens vesicle polarization. Primary fiber cell differentiation was apparent at approximately 21 hpf, before separation of the lens from the surface ectoderm, as evidenced by cell elongation, exit from the cell cycle, and expression of Zl-1, a marker for fiber differentiation. TUNEL labeling demonstrated that apoptosis was not a primary mechanism for lens separation from the surface ectoderm. CONCLUSIONS: Despite the absence of a lens vesicle in the zebrafish embryo, lens organogenesis appears to be well conserved among vertebrates. Results using three-dimensional live embryo imaging of zebrafish development showed minimal differences and strong similarities in the fate of cells in the zebrafish and mammalian lens placode.

Efficacy of ophthalmic nonsteroidal antiinflammatory drugs in suppressing anterior capsule contraction and secondary posterior capsule opacification.

PURPOSE: To evaluate the efficacy of ophthalmic nonsteroidal and steroidal antiinflammatory drugs in preventing anterior capsule contraction and secondary posterior capsule opacification (PCO) using an experimental cataract model. SETTING: Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan. METHODS: Eight-week-old albino rabbits weighing about 2 kg each had phacoemulsification and intraocular lens implantation. After surgery, the rabbits were divided into 3 treatment groups: diclofenac sodium ophthalmic solution, bromfenac sodium ophthalmic solution, and betamethasone ophthalmic solution. In each group, the ophthalmic solution was applied to the left eye of each rabbit twice daily; the right eye served as an untreated control. To evaluate anterior capsule contraction, the percentage of incised anterior capsule opening area was calculated on diaphanoscopic images obtained with an EAS-1000 anterior segment analyzer. For evaluation of PCO, a tissue section was stained with hematoxylin-eosin and observed under a light microscope. The PCO was quantified on the basis of the thickness of the lens epithelial cell layer on the central subcapsular area and compared among groups. RESULTS: Fifteen albino rabbits were used in the study. Treatment with diclofenac sodium and bromfenac sodium ophthalmic solution prevented progression of anterior capsule contraction and PCO. Treatment with bromfenac ophthalmic solution did not prevent either complication. CONCLUSION: Postoperative treatment with ophthalmic nonsteroidal antiinflammatory drug solutions prevented anterior capsule contraction and PCO in rabbit eyes.