[Hazards posed by LEDs? : A comparative study]. / Gefahr durch LED-Licht? : Eine vergleichende Untersuchung.

BACKGROUND: The increasing use of light-emitting diodes (LEDs) for lighting applications and displays is giving rise to public and professional concern that blue LED emissions could damage the retina or via the proven influence on the melatonin levels disrupt the human day-night rhythm. OBJECTIVE: The study aimed to measure the emission of LEDs and other relevant light sources and evaluate the results comparatively with the help of suitable evaluation functions in order to recognize whether LEDs differ considerably from other light sources in their hazard potential. MATERIAL AND METHODS: The spectra of a cold white and a warm white LED, a white tablet LED display, a fluorescent tube and a halogen lamp were measured and evaluated together with a sunlight spectrum relative to each other using the blue light hazard retina weighting function and the circadian action function. RESULT: Since LEDs can be very different, relative LED ratings also vary greatly. The warm white LED is the one with the lowest risk of blue light retinal damage and the lowest potential for inhibition of melatonin formation and in this respect even gentler than halogen lamps. For cold white LEDs, the values for photochemical retinal danger as well as for the expected inhibition of melatonin formation are much greater. The values for the tablet LED display are even higher. CONCLUSION: Not only LEDs but all examined light sources emit in the blue spectral range, so that in principle they represent a retinal hazard. Depending on the employed LED type, this hazard may be greater or less compared to conventional light sources but even cold white LEDs are rated slightly better than sunlight at noon. To support consumers it might be helpful to classify LEDs and other illuminants by their potential hazard to the eye, as they are already labelled with respect to their energy efficiency.

[Proteome analysis of undiluted vitreous humor in patients with branch retinal vein occlusion]. / Proteomanalyse unverdünnter Glaskörperflüssigkeit bei Patienten mit einem Venenastverschluss.

BACKGROUND: The pathophysiological mechanisms of macular edema secondary to branch retinal vein occlusion (BRVO) remain unclear. OBJECTIVES: To analyze the protein profile of human vitreous of patients with BRVO and to identify specific dysregulated proteins. MATERIALS AND METHODS: Undiluted vitreous humor samples from patients with treatment naïve BRVO and 15 controls with idiopathic floaters were analyzed in this clinical-experimental study using capillary electrophoresis coupled to a mass spectrometer (CE-MS) and tandem mass spectrometry (MS/MS). Quantitative analysis of the dysregulated proteins was performed with enzyme-linked immunosorbent assay (ELISA). Protein-protein interactions were depicted with the STRING database. RESULTS: A total of 84 proteins were found in the human vitreous samples of 15 patients with BRVO and 15 controls. In all, 14 proteins were significant when comparing the signal intensities of BRVO and control samples. Six significant dysregulated proteins with p < 0.001 were further verified with ELISA. Clusterin, complement factor C3, prostaglandin-H2 D­isomerase and vitronectin were significantly upregulated in the BRVO group and opticin was downregulated. The protein interactions analysis showed associations with inflammatory cascades, matrix changes, mechanisms of cell survival und death. CONCLUSIONS: The results of the study reveal that the proteomic composition of vitreous humor differed significantly between the patients with BRVO and the controls. Whether the identified proteins may serve as potential biomarkers for pathophysiology, diagnostics or therapy should be examine in further studies.

[Ophthalmic diaphanoscopy]. / Diaphanoskopie am Auge.

Diaphanoscopy is an almost 150-year-old diagnostic procedure based on the transillumination of the wall of the eyeball. One of the most important fields of application is the detection of tumors, which can be distinguished from the rest of the tissue by their reduced light transmission. Other fields of application include the diagnosis of retinal tears and holes, the detection of foreign bodies in the vitreous body and the control of coagulative measures in the ciliary body. In comparison to other techniques, diaphanoscopy requires only little effort and is very gentle on patients.

[Fiberless miniature chandelier LED endoilluminator for pars plana vitrectomy]. / Faserloser Miniatur-Chandelier-LED-Endoilluminator für die Pars-plana-Vitrektomie.

BACKGROUND: Currently available chandelier endoilluminators for pars plana vitrectomy consist of conventional optical fibers coupled to a light source. The light probes of these fibers now provide wide emittance angles but it is still often not possible to illuminate the whole intraocular space via just one incision. Therefore, several light probes or additional handheld endoilluminators have to be used simultaneously or the lights have to be repositioned during surgery. OBJECTIVE: The presented prototype of a fiberless chandelier light-emitting diode (LED) endoilluminator aims at illuminating the whole intraocular space with just one incision while reducing the risk of harming the retina. MATERIAL AND METHODS: The light source is a white LED with a conical tip that allows stable fixation within an incision. The physical properties of these LEDs were determined and used for calculating the relevant irradiance to assess the risk of causing harm to the eye. The illumination of the intraocular space was investigated using porcine eyes. RESULTS: The illumination of porcine eyes with the modified LEDs was bright and homogeneous. Measurements and subsequent calculations proved that the expected thermal load and photochemical hazard were very low for human eyes. CONCLUSION: The hitherto existing experimental results on porcine eyes and the theoretical considerations on human eyes were found to be positive; therefore, it is expected that this new fiberless chandelier LED endoilluminator will prove to be advantageous for human patients. It promises a reduced number of incisions with a simplified handling and need to add handheld light sources only if minimal intensity oblique illumination is helpful together with the chandelier illumination. This contributes to a significant reduction of phototoxicity risks and additionally there is a chance for a cost reduction because expensive xenon or mercury lamps are no longer necessary. These expectations have to be verified by further studies on human eyes.