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.

Clinical evaluation of the transparency of hydrophobic acrylic intraocular lens optics.

PURPOSE: To clinically evaluate postoperative changes in the transparency of hydrophobic acrylic intraocular lenses (IOLs). SETTING: Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan. DESIGN: Case-control study. METHODS: Eyes having phacoemulsification were randomly assigned to have implantation of 1 of 3 hydrophobic acrylic IOL models. The IOLs were photographed at 0 degree and 90 degrees 1 week, 6 months, and 1 year after implantation using a Nidek EAS-1000 anterior chamber analyzer in slit mode. The images were used to determine the intensity of light scattering in the surface and middle regions of the IOL optic. RESULTS: The study comprised 65 eyes of 57 patients with a mean age of 72.5 years. The rate of increase in light-scattering intensity was similar in the middle and surface regions of the Tecnis ZA9003 aspheric IOL. The increase in light-scattering intensity in both regions of the AF-1 VA-60BB spherical IOL was greater than that in the aspheric IOL at all the measurement points. The intensity of light scattering was highest and tended to increase over time in both regions of the AcrySof SA60AT spherical IOL; the rate of increase in intensity was higher in the surface region than in the middle region, and the difference was significantly greater at 6 months and 1 year than at 1 week. CONCLUSION: Our results suggest that AcrySof SA60AT and AF-1 VA-60BB IOLs are likely to develop glistenings over time and that the former may develop whitening.

Comparison of anterior capsule contraction between 5 foldable intraocular lens models.

PURPOSE: To compare anterior capsule contraction in cataract patients having implantation of 1 of 5 foldable intraocular lens (IOL) models and evaluate lens epithelial cell (LEC) adhesion to each model. SETTING: Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan. METHODS: This study comprised 115 patients (126 eyes) without systemic or ocular complications who had phacoemulsification with IOL implantation. The eyes were randomly assigned to receive 1 of the following IOLs: acrylic MA60BM (Alcon), SA60AT (Alcon), AR40e (Advanced Medical Optics), or YA-60BBR (Hoya) or a silicone AQ310NV (Canon). Two weeks and 1, 3, and 6 months postoperatively, the anterior capsule opening area was measured using an anterior segment analysis system (EAS-1000, Nidek) and the percentage of anterior capsule contraction was compared for each postoperative period and IOL. Cell adhesion to each IOL type was evaluated using LECs from albino rabbits. RESULTS: The mean age of the patients was 73.6 years +/- 5.6 (SD). Eyes with the AQ310NV and AR40e IOLs had statistically significantly greater anterior capsule contraction. The rabbit study showed statistically significantly less LEC adhesion on these 2 IOL models. CONCLUSIONS: Anterior capsule contraction was significantly greater with the AQ310NV and AR40e IOLs than with the other IOLs. Results indicate that cell adhesion to the IOL is an important factor in preventing anterior capsule contraction.

[Protective effect on the corneal endothelium and remaining effect at the anterior chamber for three different kinds of viscoelastic devices].

PURPOSE: The present study was performed to evaluate the corneal endothelium protection and anterior chamber stagnation abilities of three different types of viscoelastic substances (Healon, Viscoat, HealonV). METHODS: Viscoelastic substances were selected at random for 120 eyes with cataracts, and the postoperative reduction rates of the corneal endothelium cells were compared. The residual viscoelastic substances after filling of the anterior chamber of pig eyes and aspiration with a handpiece were measured by an anterior eye segment image analysis system. The same procedures were performed in rabbit eyes and the residual levels of viscoelastic substances on the corneal endothelium were photographed histologically. RESULTS: The reduction rate of endothelium corneal cells tended to decrease with Viscoat three months after surgery. The results obtained with the anterior eye segment image analysis system showed that the residual level in the anterior chamber was higher with Healon. Histological analyses demonstrated residual Viscoat at the center of the corneal endothelium after perfusion. CONCLUSION: HealonV was superior in terms of spatial retention and Viscoat had corneal endothelium protection potential.