Hypoxic Processes Induce Complement Activation via Classical Pathway in Porcine Neuroretinas.

Considering the fact that many retinal diseases are yet to be cured, the pathomechanisms of these multifactorial diseases need to be investigated in more detail. Among others, oxidative stress and hypoxia are pathomechanisms that take place in retinal diseases, such as glaucoma, age-related macular degeneration, or diabetic retinopathy. In consideration of these diseases, it is also evidenced that the immune system, including the complement system and its activation, plays an important role. Suitable models to investigate neuroretinal diseases are organ cultures of porcine retina. Based on an established model, the role of the complement system was studied after the induction of oxidative stress or hypoxia. Both stressors led to a loss of retinal ganglion cells (RGCs) accompanied by apoptosis. Hypoxia activated the complement system as noted by higher C3+ and MAC+ cell numbers. In this model, activation of the complement cascade occurred via the classical pathway and the number of C1q+ microglia was increased. In oxidative stressed retinas, the complement system had no consideration, but strong inflammation took place, with elevated TNF, IL6, and IL8 mRNA expression levels. Together, this study shows that hypoxia and oxidative stress induce different mechanisms in the porcine retina inducing either the immune response or an inflammation. Our findings support the thesis that the immune system is involved in the development of retinal diseases. Furthermore, this study is evidence that both approaches seem suitable models to investigate undergoing pathomechanisms of several neuroretinal diseases.

Stability and Visual Outcomes of the Capsulotomy-Fixated FEMTIS-IOL After Automated Femtosecond Laser-Assisted Anterior Capsulotomy.

PURPOSE: To evaluate stability and performance of a new monofocal anterior capsulotomy-fixated intraocular lens (IOL) (FEMTIS; Teleon Surgical B.V., Spankeren, Netherlands) after femtosecond laser-assisted cataract surgery (FLACS). DESIGN: Prospective, multicenter, interventional, noncomparative case series. METHODS: FLACS with FEMTIS IOL was performed in 336 eyes of 183 cataract patients with fixation of the IOL to the anterior capsulotomy followed up for 12 months. Examination included uncorrected distance visual acuity (UDVA), best-corrected visual acuity (CDVA), subjective refraction, IOL centration, posterior capsule opacification (PCO), and investigators' satisfaction questionnaire. RESULTS: At 12 months, mean IOL rotation was 1.50 ± 1.76 degrees and decentration 0.14 ± 0.14 mm from baseline (day of surgery). Mean horizontal IOL tilt was 0.70 ± 0.60 degrees and vertical 1.15 ± 1.06 degrees relative to the baseline (crystalline lens). Mean distance between IOL and iris was 0.32 mm to 0.36 mm for all measured meridians. Mean UDVA was 0.12 ± 0.14 logMAR (range -0.20 to 0.54 logMAR), mean CDVA -0.01 ± 0.09 logMAR (range -0.30 to 0.20 logMAR). Mean spherical equivalent was 0.35 ± 0.53 diopter (D) and 98% of eyes (n = 235) were within ±1.0 D. Median PCO score was 1 with an Nd:YAG laser rate of 3.1% after 12 months. Most surgeons were very satisfied (median score: 1) with surgery and implanted IOL. CONCLUSIONS: Implantation of FEMTIS IOL provided excellent visual and stable refractive outcomes. IOL decentration was very low compared to other published studies and showed an exceptional high in-the-bag stability over a 12-month period. This lens benefits from femtosecond laser capsulotomies. It can be positioned very predictably and offers an optimal platform for toric and multifocal IOL optics.

Cortex removal after laser cataract surgery and standard phacoemulsification: a critical analysis of 800 consecutive cases.

PURPOSE: To evaluate the ease of anterior cortex removal and hydrodissection of the lens in femtosecond laser-assisted cataract surgery compared with standard phacoemulsification. METHODS: In the femtosecond laser-assisted cataract surgery group (400 eyes), a femtosecond laser was used for capsulotomy and followed by lens fragmentation. In the standard group, the capsulorhexis was performed manually. In both groups, a normal hydrodissection was set, the nucleus was aspirated with or without ultrasound phacoemulsification energy, and residual cortex removal and posterior capsule polishing were performed using bimanual irrigation/aspiration. The primary end point was the time (in seconds) required for the removal of the cortex from instrument insertion in the eye until aspiration tip removal. Secondary end points were the effective phacoemulsification time, quality of the anterior capsule, and anterior or posterior capsule ruptures. RESULTS: Cortex removal time measured 30 ± 13 seconds (range: 10 to 76 seconds) for the standard group and 27 ± 10 seconds (range: 9 to 72 seconds) for the femtosecond laser-assisted cataract surgery group (P < .005). After laser-assisted capsulotomy, one capsule was still adherent following removal by forceps. No anterior or posterior capsular tears were observed in either group. CONCLUSIONS: In femtosecond laser-assisted cataract surgery, the biaxial cortex removal time was comparable with the time in standard phacoemulsification.

Inflammatory response after phacoemulsification treated with 0.5% prednisolone acetate or vehicle.

PURPOSE: To compare the inflammatory response after phacoemulsification and intraocular lens implantation, using postoperative treatment with 0.5% prednisolone acetate eye drops or vehicle. DESIGN: A multi-center randomized double-masked vehicle-controlled, parallel group phase IV study. METHODS: Sixty-two eyes of 62 patients undergoing phacoemulsification were examined at five German university eye hospitals (Mainz, Heidelberg, Bonn, Erlangen, Frankfurt/Main). Patients received either 0.5% prednisolone acetate eye drops (group 1) or vehicle eye drop solution (group 2) four times a day until day 2, then open-label treatment with 0.5% prednisolone acetate eye drops four times a day continued until day 14 for all patients. Postoperative inflammation was evaluated by using laser flare photometry. Secondary efficacy variables included visual acuity, intraocular pressure, corneal edema, bulbar conjunctival hyperemia and ocular discomfort. RESULTS: In group 1, median flare rose from 7.4 photon counts/ms preoperatively to 31.0 photon counts/ms at day 1. In group 2, the flare increased from 8.6 photon counts/ms preoperatively to 30.5 photon counts/ms at day 1. The differences between the groups were not statistically significant. At day 3, flare measures were reduced in group 1 but remained fairly unchanged in group 2 (20.8 photon counts/ms vs 32.6 photon counts/ms), which was statistically significant (p = 0.0055). At day 14, photon counts were comparable in both groups (13.0 photon counts/ms vs 11.4 photon counts/ms), respectively. Both groups were comparable regarding secondary efficacy variables. CONCLUSIONS: 0.5% prednisolone acetate appeared to be significantly more effective as vehicle in controlling intraocular inflammation after phacoemulsification; both groups had a similar safety profile.

Ray tracing for intraocular lens calculation.

PURPOSE: To improve accuracy in intraocular lens (IOL) calculations and clarify the effect of various errors. SETTING: University eye hospitals, Mainz, Germany, and Vienna, Austria. METHODS: A numerical ray-tracing calculation has been developed for the pseudophakic eye. Individual rays are calculated and then undergo refractions on all surfaces of the IOL and cornea. The calculations do not use approximations; ie, the refractions are calculated exactly using Snell's law. Rays can be calculated for any distance from the optical axis and for other parameter variations. The effects of aspheric surfaces can also be investigated. Instead of IOL powers, manufacturers' IOL data (radii, refractive index, thickness) are used in the calculations for different IOL types. The resulting optical quality is visualized by using Landolt rings superimposed on the grid of retinal receptors. RESULTS: Intraocular lens design, corneal asphericity, and specific spherical aberration influence the visual quality of the pseudophakic eye significantly. The IOL refractive power is an ambiguous parameter that cannot characterize the visual outcome sufficiently accurately for an IOL implanted at a given position. The effects can be calculated only in numerical ray tracing, not in Gaussian optics. The accuracy of numerical ray tracing is independent of axial length. Therefore, very long or very short eyes gain the most from the higher accuracy of this approach. For average-size eyes, however, the results are the same as with SRK calculations. CONCLUSION: Calculations in Gaussian optics should be replaced by state-of-the-art numerical methods, which can be run on any standard personal computer.