Impact of Intravitreal Dexamethasone Implant on Vessel Diameters in Patients with Retinal Vein Occlusion

Purpose. To investigate the vasomotor responses and diameter of retinal vessels in patients with macular edema secondary to retinal vein occlusion (RVO) who were treated with intravitreal dexamethasone implant. Methods. We enrolled 17 eyes of 17 patients with macular edema secondary to RVO. All patients were evaluated through optical coherence tomography and dynamic and static retinal vessel analysis, using the Dynamic Vessel Analyzer (Imedos, Jena, Germany) before administration (baseline) and 1 week, 1 month, and 2 months after administration of intravitreal dexamethasone. Measurements of patients were compared to those of 17 eyes of age- and sex-matched control subjects. Results. In static analysis, arteriovenous ratio (AVR) in control subjects was 0.86 (0.80–0.88). In RVO patients, baseline AVR was 0.71 (0.54–0.84) and significantly lower than that in control subjects (p=0.016). Baseline AVR in the RVO group was significantly lower than AVR at month 1 and month 2 (p=0.001 and p<0.001, respectively). CRVE in healthy control subjects was 183.59 ± 21.79 measurement units (MU) which was significantly different from CRVE of RVO eyes at baseline (207.00 ± 26.35 MU) (p=0.008). Static analysis showed a significant decrease of central retinal vein equivalent (CRVE) from baseline to 1 week, 1 month, and 2 months (p<0.001, p<0.001, and p<0.001, respectively). CRAE in the control group was 176.24 ± 22.45 MU. CRAE in the RVO group was significantly lower at baseline, week 1, month 1, and month 2 compared to that in the control group (p=0.008, p=0.003, p=0.013, and p=0.011, respectively). Dynamic analysis showed that maximum venous and arterial dilations did not statistically differ from baseline to 1 week, 1 month, or 2 months. Conclusion. Using the Dynamic Vessel Analyzer, we found that retinal veins in patients with RVO were significantly larger compared to those in the control group, and intravitreal dexamethasone treatment reduced the diameters of these veins.

Retinal vessels functionality in eyes with central serous chorioretinopathy

PurposeTo analyse static characteristics and dynamic functionality of retinal vessels in eyes with central serous chorioretinopathy (CSCR) by means of Dynamic Vessel Analyzer (DVA).MethodsPatients presenting with treatment-naïve CSCR and normal subjects (controls) matched for age and sex between May 2015 and November 2015 were enrolled in the study. Participants underwent a complete ophthalmological examination, including dynamic and static retinal vessels analysis by DVA.ResultsA total of 28 eyes of 28 subjects (14 eyes for each group) were included in the analysis. Dynamic analysis during stimulation by flickering light showed mean venous dilation of 3.3%±2.0% in patients with CSCR and 5.5%±2.6% in controls (p=0.0258); mean arterial dilation did not differ between patients and controls (3.2%±2.5% and 4.2%±1.5%, p=0.2). No differences were reported at static retinal analysis between patients with CSCR and control subjects. Subfoveal choroidal thickness as evaluated by optical coherence tomography was 438.6±86.1 µm in CSCR eyes, significantly increased compared with control subjects (301.5±72.5 µm, p=0.0001).ConclusionsDynamic analysis revealed a reduced retinal venous dilation in response to flicker light stimulation in CSCR eyes. The decreased retinal vein response to flicker light stimulation, possibly due to increased sympathetic tone and potentially leading to venous stasis, together with the increased choroidal thickness may help understand CSCR and give insights in its pathogenesis.

Influence of Latanoprost on Retinal Microcirculation in Glaucoma

Purpose : To test whether latanoprost has an influence on ocular haemodynamics, considering the general reputation of prostaglandins which is frequently associated with vasoconstriction. The effect of latanoprost on the retinal blood supply of treatment-naïve glaucoma patients was tested. Materials and Methodology : 13 patients (7 male, 6 female) who had just recently been diagnosed with primary open-angle glaucoma (POAG) were treated with latanoprost (0.005%). The average age of our study group was 63.8 years (+/- 2.9 years). The drug’s effect on retinal autoregulation was assessed by flicker test using the Dynamic Vessel Analyzer (DVA). Examinations took place before initializing treatment, after 4 weeks and once again after 4 to 6 months. Results : In our group of POAG patients, the IOP under treatment was significantly reduced about 25%. No intraindividual differences in systemic blood pressure and heart rate were observed. In DVA measurements of glaucoma patients, the maximum flicker dilation of the arteries was significantly lower than reported for healthy volunteers. Beyond that, POAG patients did not show significant differences in vessel diameters, peak amplitudes as well as maximum dilations of retinal arteries and veins before and under treatment with latanoprost (0.005%). Conclusion : Latanoprost markedly lowered the IOP but it did not exert a significant effect on retinal haemodynamics. There was neither a tendency towards vasoconstriction nor towards vasodilation. Sustaining reperfusion damage after topical latanoprost therapy thus seems to be highly unlikely. Further studies must show if sole IOP lowering or a dual positive effect – IOP lowering and improvement of retinal vessel autoregulation – have a more positive impact on the long term follow-up of glaucoma patients.

Laser Cyclophotocoagulation Enhances the Regulative Capacity of Retinal Vessels in Glaucoma

Purpose: To determine the effects of laser surgical IOP reduction by means of transscleral cyclophotocoagulation (CPC) on retinal blood flow parameters in glaucoma patients using Dynamic Vessel Analysis (DVA). Materials and Methodology: 26 patients (average age: 70 years) with a long history of primary open angle glaucoma underwent CPC. The effect on the reactive capacity of retinal vessels was assessed before and 6-8 weeks after CPC by means of the Dynamic Vessel Analyzer (DVA) using flicker light provocation. Results: In our group of POAG patients, IOP was significantly reduced about approximately 20% by CPC while systemic blood pressure and heart rate were not changed. The most obvious differences between the pre- and postoperative DVA measurements could be observed in the maximal dilation of the retinal arteries which increased from 0.75 % (+/- 0.6) to 3.17 % (+/- 0.5) with an average increase of 2.4 % (p<0.01). In addition, the ability of the arteries for constriction improved significantly (p<0.05) while the dynamic responses of the veins and the initial baseline values (MU) of the vessel diameters did not change. Conclusions: Our results of DVA measurements after an IOP-lowering laser surgical intervention (CPC) reveal a significant recovery of the regulative capacity of retinal arteries in glaucoma patients that has up to now neither been properly documented nor appreciated. Future studies with long-term follow-up must determine the clinical importance of these findings for the treatment of glaucoma patients.