[Show abstract][Hide abstract] ABSTRACT: Glaucoma is the leading cause of preventable blindness in the western world. Investigation of high-resolution retinal nerve fiber layer (RNFL) images in patients may lead to new indicators of its onset. Adaptive optics (AO) can provide diffraction-limited images of the retina, providing new opportunities for earlier detection of neuroretinal pathologies. However, precise processing is required to correct for three effects in sequences of AO-assisted, flood-illumination images: uneven illumination, residual image motion and image rotation. This processing can be challenging for images of the RNFL due to their low contrast and lack of clearly noticeable features. Here we develop specific processing techniques and show that their application leads to improved image quality on the nerve fiber bundles. This in turn improves the reliability of measures of fiber texture such as the correlation of Gray-Level Co-occurrence Matrix (GLCM).
[Show abstract][Hide abstract] ABSTRACT: The molecular pathways contributing to visual signal transduction in the retina generate a high energy demand that has functional and structural consequences such as vascularization and high metabolic rates contributing to oxidative stress. Multiple signaling cascades are involved to actively regulate the redox state of the retina. Age-related processes increase the oxidative load, resulting in chronically elevated levels of oxidative stress and reactive oxygen species, which in the retina ultimately result in pathologies such as glaucoma or age-related macular degeneration, as well as the neuropathic complications of diabetes in the eye. Specifically, oxidative stress results in deleterious changes to the retina through dysregulation of its intracellular physiology, ultimately leading to neurodegenerative and potentially also vascular dysfunction. Herein we will review the evidence for oxidative stress-induced contributions to each of the three major ocular pathologies, glaucoma, age-related macular degeneration, and diabetic retinopathy. The premise for neuroprotective strategies for these ocular disorders will be discussed in the context of recent clinical and preclinical research pursuing novel therapy development approaches.
International Journal of Molecular Sciences 02/2014; 15(2):1865-86. · 2.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: The correct self-administration of topical antiglaucomatous eye drops is important for the success of glaucoma treatment. Individual impairment, like increased age, decreased visual acuity, impaired visual-field perception or the frequency of drug appliance may influence a correct application technique and the patients compliance and therewith intraocular pressure (IOP). The aim of this study was to explore alterations of IOP due to self versus external administration (by trained medical personnel) of topical antiglaucomatous eye drops due to impairing factors. Material and Methods: A prospective analysis was undertaken of 123 patients with primary chronic open-angle glaucoma receiving a diurnal intraocular pressure (DIP) measurement over 72 hours at our department. During the first 24 hours, the application of topical eye drops was self-administered by patients (SA), while the application of eye drops within the following 48 hours was performed by trained medical personnel (EA). Alterations of mean intraocular pressure (MIP) and diurnal fluctuations (DF) between EA and SA were analysed with regard to initial IOP, restrictions of visual field perception, visual acuity, age, general health status and frequency of daily eye drop administration. Results: Overall comparable MIP in SA and EA was seen. 19.2-43.9 % of the patients with an initial IOP ≥ 11 mmHg showed beneficial effects of EA with lowering of IOP under 15.5 mmHg. 27.6 % of the patients showed lowering of DF < 5 mmHg due to EA. EA influenced DF beneficially in cases of poor visual acuity (≤ 0.1, - 0.8 mmHg) and frequent drop administration (- 0.75 mmHg). Conclusions: Subpopulations of investigated patients showed lowering of MIP due to EA, although EA showed no MIP lowering effects in comparison with SA in general. Glaucoma-impaired patients show decreased DF by EA. Particularly beneficial influences to DF by EA were observed due to impaired visual acuity and frequent drop administration. We recommend a 72-hour DIP to evaluate individual parameters influencing the success of topical glaucomatous treatment. The benefit of EA in patients with certain impairments should be the subject of further investigations.
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