Retinal Functional and Structural Neural Indices: Potential Biomarkers for the Monitoring of Cerebral Neurodegeneration: The Maastricht Study.

BACKGROUND: If retinal indices of neurodegeneration are to be biomarkers for the monitoring of cerebral neurodegeneration, it is important to establish whether potentially modifiable risk factors for dementia are associated with retinal neurodegenerative changes. OBJECTIVE: To study associations of dementia risk factors with retinal sensitivity, an index of retinal neural function, and retinal nerve fiber layer (RNFL) thickness, an index of retinal neural structure. METHODS: We used cross-sectional data from The Maastricht Study (up to 5,666 participants, 50.5% men, mean age 59.7), and investigated associations with regression analyses (adjusted for potential confounders). RESULTS: Most risk factors under study (i.e., hyperglycemia, unhealthy diet, lower cardiorespiratory fitness, smoking, alcohol consumption, and hypertension) were significantly associated with lower retinal sensitivity and lower RNFL thickness. CONCLUSION: Findings of this population-based study support the concept that retinal neural indices may be biomarkers for the monitoring of therapeutic strategies that aim to prevent early-stage cerebral neurodegeneration and, ultimately, dementia.

Optical coherence tomography as a tool to evaluate retinal changes in Parkinson's disease.

BACKGROUND: Though Parkinson's disease (PD) is primarily a disease of the basal ganglia, recent evidence suggests that PD affects the retina. OBJECTIVE: The study was designed to evaluate the thickness of retinal nerve fiber layer (RNFL) and thickness and volume of the macula in PD and hence explore the utility of optical coherence tomography (OCT) in studying retinal changes in PD. METHODS: A prospective, hospital based evaluation of 30 patients with PD and 30 healthy controls was carried out. Various parameters such as RNFL, central macular thickness (CMT), central and total macular volumes (TMV) and retinal thickness were analyzed using OCT. RESULTS: (a) RNFL thickness was not significantly different between the patients and controls. A significant negative correlation was found between the RNFL thickness in the right nasal superior sector and the UPDRS motor score. (b) CMT was found to be significantly reduced in the right eye and a negative correlation with the UPDRS motor score was noted. (c) TMV was significantly greater in patients compared to the controls. (d) The outer retinal layer in the right nasal quadrant and the right inferior quadrants were found to be significantly thinner in patients with PD. CONCLUSIONS: We did not find any significant abnormality in the RNFL thickness in patients with PD. Decreased CMT in patients with PD and a significant negative correlation of RNFL thickness and CMT with severity of PD suggest a remote possibility of dopaminergic depletion in the retina. However long term studies are warranted to validate our findings.

Retinal oxygen saturation in retinitis pigmentosa and macular dystrophies in asian-Indian eyes.

PURPOSE: To study the oxygen-saturation profiles in RP and macular dystrophies and compare them with age-matched healthy controls. METHODS: In a cross-sectional prospective study, 62 subjects with RP, 23 with macular dystrophies, and 78 controls were enrolled, and retinal oximetry was performed with the Oxymap T1 retinal oximeter. The images were analyzed for oxygen saturation and diameter of retinal vessels. RESULTS: All parameters showed a significant difference among the three groups. Patients with RP showed significantly lower diameters (98.4 µm and 136.9 µm arteriolar and venous) (P < 0.001), higher saturations (102.3% and 59.1%) (P < 0.001; 0.06), and higher arterio-venous saturation difference (AVSD) (43%) (P < 0.001) compared with the other two groups. Macular dystrophies showed higher global arteriolar values (96.7%) and AVSD (41.6%) but comparable venous values (54.9%) to the control group (90.6%, 57.4%, and 33.3%). CONCLUSIONS: Oximetry is sensitive in quantifying hemodynamic changes in retinal dystrophies. It is still unclear whether these hemodynamic changes are a cause or a result of the disease process.

Adaptive optics imaging of the retina.

Adaptive optics is a relatively new tool that is available to ophthalmologists for study of cellular level details. In addition to the axial resolution provided by the spectral-domain optical coherence tomography, adaptive optics provides an excellent lateral resolution, enabling visualization of the photoreceptors, blood vessels and details of the optic nerve head. We attempt a mini review of the current role of adaptive optics in retinal imaging. PubMed search was performed with key words Adaptive optics OR Retina OR Retinal imaging. Conference abstracts were searched from the Association for Research in Vision and Ophthalmology (ARVO) and American Academy of Ophthalmology (AAO) meetings. In total, 261 relevant publications and 389 conference abstracts were identified.

Low Vision Aids in Glaucoma.

A large number of glaucoma patients suffer from vision impairments that qualify as low vision. Additional difficulties associated with low vision include problems with glare, lighting, and contrast, which can make daily activities extremely challenging. This article elaborates on how low vision aids can help with various tasks that visually impaired glaucoma patients need to do each day, to take care of themselves and to lead an independent life.

Bevacizumab in Glaucoma: Where do We Stand?

The use of antivascular endothelial growth factors such as bevacizumab and ranibizumab has brought about a revolution in management protocols of various ophthalmic disorders. A lot has been written about these agents, still lacunae exist in our understanding due to paucity of randomized control trials with large number of patients. This brief review attempts to throw light on the clinical applications of these molecules for glaucoma. HOW TO CITE THIS ARTICLE: Khanna A. Bevacizumab in Glaucoma: Where do We Stand? J Current Glau Prac 2012;6(2):75-78.