The artificial iris prosthesis revealed a good clinical outcome in terms of long-term stability, cosmetic appearance, visual function, and represents a good functional iris diaphragm for compartmentalisation. Complications such as glaucoma, darkening of iris tissue, and need for consecutive anterior segment surgery are clearly associated with implants with integrated fiber mesh, but not to those without. Hence, the use of full iris prostheses without embedded fiber mesh, even in cases with remnant iris, and the use of slightly smaller implants than officially recommended may be beneficial.
The aim of this study was to evaluate the pupil size of normal subjects at different illumination levels with a novel pupillometer. The pupil size of healthy study participants was measured with an infraredvideo PupilX pupillometer (MEye Tech GmbH, Alsdorf, Germany) at five different illumination levels (0, 0.5, 4, 32, and 250 lux). Measurements were performed by the same investigator. Ninety images were executed during a measurement period of 3 seconds. The absolute linear camera resolution was approximately 20 pixels per mm. This cross-sectional study analysed 490 eyes of 245 subjects (mean age: 51.9 ± 18.3 years, range: 6-87 years). On average, pupil diameter decreased with increasing light intensities for both eyes, with a mean pupil diameter of 5.39 ± 1.04 mm at 0 lux, 5.20 ± 1.00 mm at 0.5 lux, 4.70 ± 0.97 mm at 4 lux, 3.74 ± 0.78 mm at 32 lux, and 2.84 ± 0.50 mm at 250 lux illumination. Furthermore, it was found that anisocoria increased by 0.03 mm per life decade for all illumination levels (R 2 = 0.43). Anisocoria was higher under scotopic and mesopic conditions. This study provides additional information to the current knowledge concerning age-and light-related pupil size and anisocoria as a baseline for future patient studies. ARTICLE HISTORY
Background/Purpose: To demonstrate possible complications of a new intraocular lens for sutureless secondary scleral implantation and modifications of the surgical technique to optimize outcomes. Methods: A retrospective study of 16 eyes (16 patients) who underwent a secondary intraocular lens implantation using the Carlevale intraocular lens (Soleko, Italy) with two anchor haptics for intrascleral implantation (mean follow-up 2.2 months). Results: The visual acuity did not improve statistically significantly postoperatively (P = 0.601). Seven (44%) patients suffered from postoperative hypotonia (intraocular pressure <5 mmHg) during the first three postoperative days. Conclusion: Owing to the early postoperative hypotony, we decided to modify the surgical technique. We present several suggestions to optimize the technique and outcome such as positioning the sclerotomies at the 2 and 8 o'clock positions, using 27 G trocars alone and suturing the frown incisions using self-resorbing sutures.
Purpose To determine the viscoelasticity of human vitreous bodies and its changes with age in order to benefit the understanding and therapy of vitreoretinal diseases. Methods In a postmortem study, 190 human vitreous bodies were extracted from 33- to 92-year-old donors, analyzed with regard to their viscoelastic properties via dynamic mechanical analyses, and compared with bovine and porcine vitreous. Postmortem intervals and donor-related parameters were examined as potential parameters influencing vitreous viscoelasticity. Dynamic moduli of different hyaluronic acid (HA) solutions as well as human vitreous treated with HA injections were determined by frequency sweep tests. Results With age the viscoelasticity of human vitreous bodies decreased significantly and independently of postmortem intervals, diabetes, and the donor's sex. The storage modulus G′ and loss modulus G″ correlated strongly with the donor's age with r = −0.789 and r = −0.764, respectively. Bovine and porcine vitreous bodies exhibited dynamic moduli comparable only to the viscoelastic properties of aged human vitreous and are thus limited models for the simulation of the human vitreous. The viscoelasticity of aged human vitreous bodies was found to be increased after intravitreal injections of highly concentrated HA. Conclusions The present postmortem study is the first to show a significant age-related reduction in the viscoelasticity of entire human vitreous bodies. Highly concentrated HA injections may serve as a possible therapeutic approach for restoring the viscoelasticity of aged vitreous bodies. Translational Relevance These findings improve the understanding and therapy of the vitreous liquefaction with age and the associated vitreoretinal diseases.
Purpose
To study alginate- and hyaluronic acid–based hydrogels in vitro as vitreous substitutes.
Methods
Biopolymeric hydrogels based on high-molecular alginate (0.5% and 1.0%) and hyaluronic acid (1.0% and Healaflow) were compared with extracted human vitreous bodies and silicone oil (SIL-5000) regarding their optical properties (refractive index, transmission) and viscoelastic characteristics (storage modulus G′, loss modulus G″). The cytotoxic (metabolic activity, apoptosis) and antiproliferative profiles were determined using cultured human fibroblasts, ARPE-19, and photoreceptor cells. The hydrogel systems were applied to human fetal retinal pigment epithelial cells cultured for two months until maximum transepithelial electrical resistance (TEER) to investigate the effect of the gel matrices on tight junctions using TEER measurements and immunostainings against the tight junction protein ZO-1.
Results
Tested alginate- and hyaluronic acid–based hydrogels resembled the natural refractive index of human vitreous bodies (1.3356–1.3360) in contrast to SIL-5000 (1.4034) and showed high optical transparency (>90%) within the visible light region. The biopolymeric hydrogels exhibited viscoelastic properties similar to juvenile vitreous bodies with G′>G″ adjustable via different gelation times, contrary to SIL-5000 (G′
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