Foveal choroidal blood flow in age-related macular degeneration (AMD) (original) (raw)
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Twelve hour reproducibility of choroidal blood flow parameters in healthy subjects
British Journal of Ophthalmology, 2004
Aims/background: To investigate the reproducibility and potential diurnal variation of choroidal blood flow parameters in healthy subjects over a period of 12 hours. Methods: The choroidal blood flow parameters of 16 healthy non-smoking subjects were measured at five time points during the day (8:00, 11:00, 14:00, 17:00, and 20:00). Outcome parameters were pulsatile ocular blood flow as assessed by pneumotonometry, fundus pulsation amplitude as assessed by laser interferometry, blood velocities in the opthalmic and posterior ciliary arteries as assessed by colour Doppler imaging, and choroidal blood flow, volume, and velocity as assessed by fundus camera based laser Doppler flowmetry. The coefficient of variation and the maximum change from baseline in an individual were calculated for each outcome parameter. Results: None of the techniques used found a diurnal variation in choroidal blood flow. Coefficients of variation were within 2.9% and 13.6% for all outcome parameters. The maximum change from baseline in an individual was much higher, ranging from 11.2% to 58.8%. Conclusions: These data indicate that in healthy subjects the selected techniques provide adequate reproducibility to be used in clinical studies. Variability may, however, be considerably higher in older subjects or subjects with ocular disease. The higher individual differences in flow parameter readings limit the use of the techniques in clinical practice. To overcome problems with measurement validity, a clinical trial should include as many choroidal blood flow outcome parameters as possible to check for consistency.
Bulletin de la Société belge d'ophtalmologie, 2006
Laser Doppler flowmetry allows the measurement of relative choroidal blood flow in the sub-foveal region of the fundus (ChBF). This technique has been applied to the investigation of the regulation of ChBF in response to a variety of physiological stimuli (breathing different gas mixtures of O2 and CO2, varying the systemic and ocular blood perfusion pressures, light-dark transition and zero gravity) in normal subjects. Measurements in pathological conditions, such as diabetes, age-related macular degeneration and glaucoma indicate alterations of the response of ChBF to increased systemic blood pressure. The data provide a better understanding of the regulation of the choroidal circulation in the normal and diseased eye.
Choroidal vascular changes in age-related macular degeneration
Acta ophthalmologica, 2017
To assess the choroidal vascular changes using choroidal vascularity index (CVI) in patients with age-related macular degeneration (AMD) compared to controls. Enhanced depth imaging (EDI) optical coherence tomography (OCT) scans of 64 patients with unilateral or bilateral AMD were obtained. Images with a poorly demarcated choroidal-scleral interface (CSI) were excluded from the analysis. Foveal scans of 63 AMD eyes and 35 'normal fellow' eyes were analysed. Images of 30 eyes from 18 age-matched healthy subjects were included as controls. Choroidal vascularity index (CVI) was derived from binarization of EDI OCT images, using fiji software. The mean age was 56.50 ± 5.50 years for AMD patients and 52.25 ± 6.75 years for controls. All patients were treatment naïve. Subfoveal choroidal thickness (SFCT) in AMD, 'normal fellow' eyes and controls was 314.02 ± 78.80 μm, 300.88 ± 53.85 μm and 278.5 ± 65.31 μm, respectively. Choroidal vascularity index (CVI) in AMD, 'norma...
Decreased choroidal blood flow associated with retinitis pigmentosa
Eye, 1990
The intraocular pressure pulse has been measured and used to evaluate the ophthal mic arterial pressure and the ocular pulsatile blood flow in 13 retinitis pigmentosa patients and ten similar aged healthy volunteers. The light sensitivity thresholds of the central fields of all persons were recorded using the Heijl-Krakau automated perimeter. The mean pulse amplitudes of 1.2 ± 0.2 (26) and 2.3 ± 0.25 (20) mmHg in the affected and in the control groups respectively differed significantly (p<O.OOI). The corresponding pulsatile blood flows were 310 ± 24 (26) and 628 ± 40 (20) !A-I min-I. The mean ophthalmic arterial pressures in the two groups were equal. The light sensitivities in pairs of eyes of four of the patients differed substantially and in all cases the eye with the better visual performance had the higher ocular pulsatile blood flow. It is concluded that relative choroidal ischaemia is closely associated with visual loss and pigment cell degeneration in patients with retinitis pigmentosa.
American Journal of Ophthalmology, 1999
To study ocular perfusion defects in age-related macular degeneration. Twenty-five subjects with nonexudative age-related macular degeneration were compared with 25 age-matched control subjects in studies of flow velocities in several retrobulbar vessels. Color Doppler imaging, which was performed by an examiner who was masked to the subjects' assignment to the control or age-related macular degeneration group, measured peak systolic and end diastolic velocity in the ophthalmic, central retinal, and nasal and temporal posterior ciliary arteries of one eye. A resistive index was calculated from the peak systolic and end diastolic velocity. Subjects with nonexudative age-related macular degeneration showed a consistent trend toward lower peak systolic and end-diastolic velocities in the posterior ciliary arteries. For example, in the nasal posterior ciliary artery, the mean end diastolic velocity measured 1.45 +/- 0.34 cm per sec in the age-related macular degeneration group compared with 1.96 +/- 0.66 cm per sec in the control group, yielding a 26% decrease in the age-related macular degeneration group, which represented the largest difference and was highly statistically significant (P = .0012). The resistive index was not significantly altered in the nasal or temporal posterior ciliary artery. Subjects with nonexudative age-related macular degeneration did not differ from control subjects in peak systolic velocity, end diastolic velocity, or resistive index in the ophthalmic artery. In the central retinal artery, the end diastolic velocity was lower (1.37 +/- 1.95 cm per sec vs 1.95 +/- 0.66 cm per sec), whereas the resistive index was higher (0.83 +/- 0.05 vs 0.76 +/- 0.06 cm per sec), in the age-related macular degeneration group; these results were highly statistically significant (P = .0007 and P < .0001, respectively). Retrobulbar vascular changes in nonexudative age-related macular degeneration subjects include reduced flow velocities in the nasal and temporal posterior ciliary arteries. The reduced peak systolic velocity, combined with the reduced end diastolic velocity at a constant resistive index, seen in nonexudative age-related macular degeneration, is consistent with reduced bulk flow in these vessels, suggesting that choroidal perfusion is abnormal in this form of age-related macular degeneration. The changes in the central retinal artery suggest there may be a more generalized perfusion abnormality beyond the choroid in patients with age-related macular degeneration or that the central retinal artery exhibits a secondary autoregulatory response to a primary change elsewhere.
Ocular Hemodynamics In Non-Exudative Age Related Macular Degeneration
Duzce Universitesi Tip Fakültesi Dergisi, 2014
Purpose: To explore changes in retrobulbar ocular blood flow dynamics in patients with nonexudative age- related macular degeneration (ARMD). Materials and Methods: 52 patients (M=28, F=24) with ARMD and 45 age-matched healthycontrols (M=23, F=22) were included in our evaluation. Full ophthalmic examination and orbitalcolor Doppler imaging was performed in both eyes. Peak systolic and end-diastolic velocities,resistive and pulsatility indices were considered as Doppler blood flow parameters in ourevaluation. Central retinal, ophthalmic, temporal posterior ciliary and nasal posterior ciliaryarteries measurements were taken. Results: The mean age was 65.90 ± 2.05 in ARMD and 60.95 ± 1.34 in thecontrol group. Pulsatility and resistive indices in ophthalmic arteries of ARMD patients weresignificantly higher than the control group. The peak systolic and end-diastolic velocities innasal and temporal posterior ciliary arteries were significantly lower whereas pulsatility andresistive indic...
Acta Ophthalmologica, 2008
Purpose To assess the short-term changes in choroidal blood flow after photodynamic therapy (PDT) in patients with neovascular age-related macular degeneration (AMD).Methods Fourteen patients with exudative AMD were included after complete ophthalmologic examination, fluorescein and indocyanine green angiography and optical coherence tomography. Subfoveal choroidal blood flow was assessed using laser Doppler flowmetry (LDF) in both treated (n=14) and nontreated controlateral (n=8) eyes, 1 h and 1 week after PDT. Ocular perfusion pressure was calculated.Results The detection sensitivity of the LDF measurements at 2-min intervals before PDT in treated eyes was 7.4% for volume, 6.3% for velocity, and 10.4% for choroidal blood flow. Initial mean visual acuity was 0.68±0.3 logMar. Macular thickness at baseline as measured by OCT3 was at median [interquartile range], 326.5 mm[188–367]. One hour and 7 days after PDT, a significant increase in velocity (15.8% and 24.4%, respectively) and a significant decrease in volume (11% and 17.9%, respectively) were noted in treated eyes. Choroidal blood flow and ocular perfusion pressure remained similar during follow-up. No significant change in flow parameters was reported in untreated eyes.Conclusion The LDF technique provides feasible and reliable measurements of blood flow parameters before and after PDT in a selective population of patients with exudative AMD. The prognostic value of these early blood flow parameter changes also needs to be assessed.