Comparison of Neurovascular Coupling between Normal Tension Glaucoma Patients and Healthy Individuals with Laser Speckle Flowgraphy.

Background: The purpose of this pilot study was to investigate the differences in neurovascular coupling between Caucasian patients with normal tension glaucoma (NTG) and healthy subjects (HS) with laser speckle flowgraphy (LSFG). Methods: Measurement of optic nerve head blood flow was performed with LSFG. The mean blur rate of the whole optic nerve head (MA), of the big retinal vessels (MV) and of the microvasculature (MT) was analysed during continuous flicker light stimulation for four minutes. Results: We included 12 eyes from 12 Caucasian patients with a diagnosis of normal tension glaucoma and 12 eyes from 12 age- and sex-matched healthy individuals. MA, MV and MT all increased significantly in both groups during the observation period with no difference between the groups. Conclusion: Neurovascular coupling is detectable in NTG patients. Flicker light stimulation leads to a comparable increase in ocular blood flow in glaucoma patients and healthy individuals.

[Morphological retinal characteristics of patients with low vision due to diabetic macular edema]. / Morphologische retinale Charakteristika von Patienten mit einer Sehbehinderung infolge eines diabetischen Makulaödems.

BACKGROUND: The World Health Organisation (WHO) defines low vision as a best corrected visual acuity (BCVA) in the better eye between ≥0.5 logMAR and ≤1.3 logMAR. In diabetic macular edema (DME) the correlation between retinal morphology and function is not completely understood in patients with advanced visual impairment. OBJECTIVE: The aim of the study was to describe the pathomorphological similarities of DME in patients with low vision and to correlate them with clinical parameters. MATERIAL AND METHODS: Optical coherence tomography (OCT) and fluorescence angiography (FA) images were graded according to the SAVE protocol and correlated with BCVA, cataract grade and clinical parameters in order to elucidate joint features. RESULTS: Out of a total collective of 65 patients 24 had low vision and 18 of these 24 patients (75%) showed typical signs of atrophic edema according to SAVE protocol criteria (SAVE group 4); however, 6 patients were afflicted with less progressive forms of DME but still suffered from low vision. Common pathomorphological findings were a discontinuity of the ellipsoid zone (EZ; n = 18), loss of pseudosepta (n = 7), layer-disrupting cysts (n = 7) and hard exudates (n = 10). CONCLUSION: It is suggested that a disruption of the EZ, loss of pseudosepta and layer-disrupting cysts are signs of an advanced chronic DME causing low vision. A definition of characteristic pathomorphological patterns of chronic damage in OCT is important for a possible treatment discontinuation in the clinical routine.