Glaucoma and Aqueous Veins

Effect of a fixed combination of ripasudil and brimonidine on aqueous humor dynamics in mice

“…Netarsudil (AR13324), a ROCK inhibitor with norepinephrine transport inhibitory activity, has been reported to lower EVPs in rabbits 32 , and it induces dilation of episcleral vessels in enucleated human eyes, but these effects have been suggested to be mediated mostly by the norepinephrine transport inhibitory activity that causes vasoconstriction 32,33 . The precise mechanisms regulating episcleral circulation remain unclear 34,35 because the interplay between the blood flow and vascular resistance in the episcleral supply arterioles, various arteriovenous anastomoses (AVAs), and muscular veins [36][37][38][39][40][41] is complex. Pharmacologically induced vasodilation and vasoconstriction of the episcleral vasculature can alter the blood flow through AVAs, affecting the EVP, the flow of aqueous into the episcleral veins, and the IOP 40 .…”

Effect of a fixed combination of ripasudil and brimonidine on aqueous humor dynamics in mice

“…Netarsudil (AR13324), a ROCK inhibitor with norepinephrine transport inhibitory activity, has been reported to lower EVPs in rabbits 32 , and it induces dilation of episcleral vessels in enucleated human eyes, but these effects have been suggested to be mediated mostly by the norepinephrine transport inhibitory activity that causes vasoconstriction 32,33 . The precise mechanisms regulating episcleral circulation remain unclear 34,35 because the interplay between the blood flow and vascular resistance in the episcleral supply arterioles, various arteriovenous anastomoses (AVAs), and muscular veins [36][37][38][39][40][41] is complex. Pharmacologically induced vasodilation and vasoconstriction of the episcleral vasculature can alter the blood flow through AVAs, affecting the EVP, the flow of aqueous into the episcleral veins, and the IOP 40 .…”

Aqueous outflow imaging techniques and what they tell us about intraocular pressure regulation

“…Pulsatile AO was initially reported by Ascher 80 and was thought to originate from SC in synchrony with ocular pulsation. 80,81 The static nature of OCT and OCT-A is a significant limitation when imaging dynamic aspects of the AO system. Li et al 35,82 described a novel OCT technique to enable assessment of TM motion in living human eyes.…”

Aqueous outflow regulation – 21st century concepts

“…We have unparalleled evidence of physiologic outflow mechanisms provided through in vivo, direct noninvasive, observations of aqueous flow into episcleral veins ( Goldmann, 1946a ) Pulsatile Aqueous Vein Flow Video ( Vid 1 ) 1-s2.0-S1350946220300896-mmc1.mp4 ). A large body of literature documents directly observable evidence of abnormal pulsatile flow in glaucoma ( Ascher, 1942a , 1944 , 1949a; Goldmann, 1948 ; Ascher and Spurgeon, 1949b ; Kleinert, 1951c ; Johnstone et al, 2010 ) ( Fig. 3 ).…”

“…3 ). Ascher and Goldmann, the first clinician-scientists to identify flow into aqueous veins, reported pulsatile flow as a salient feature ( Ascher, 1942a ; Goldmann, 1946a ). Pulsatile outflow originates in SC and is synchronous with the ocular pulse ( Ascher, 1961 ; Johnstone et al, 2010 ).…”

“…Noninvasive aqueous angiography techniques of Ascher explore the normal circumferential distribution of aqueous flow into the episcleral veins on the eye’s surface in healthy humans ( Ascher, 1942a ). Typically, only two or three aqueous veins are visible on the eye’s surface, and a quantitative study indicates that only two such veins can carry all the aqueous flow ( Stepanik, 1954a , 1957 ; Stepanik and Kemper, 1954b ; Ascher, 1961 ).…”

Effect of a fixed combination of ripasudil and brimonidine on aqueous humor dynamics in mice

“…Netarsudil (AR13324), a ROCK inhibitor with norepinephrine transport inhibitory activity, has been reported to lower EVPs in rabbits 32 , and it induces dilation of episcleral vessels in enucleated human eyes, but these effects have been suggested to be mediated mostly by the norepinephrine transport inhibitory activity that causes vasoconstriction 32,33 . The precise mechanisms regulating episcleral circulation remain unclear 34,35 because the interplay between the blood flow and vascular resistance in the episcleral supply arterioles, various arteriovenous anastomoses (AVAs), and muscular veins [36][37][38][39][40][41] is complex. Pharmacologically induced vasodilation and vasoconstriction of the episcleral vasculature can alter the blood flow through AVAs, affecting the EVP, the flow of aqueous into the episcleral veins, and the IOP 40 .…”

Aqueous outflow imaging techniques and what they tell us about intraocular pressure regulation

“…Pulsatile AO was initially reported by Ascher 80 and was thought to originate from SC in synchrony with ocular pulsation. 80,81 The static nature of OCT and OCT-A is a significant limitation when imaging dynamic aspects of the AO system. Li et al 35,82 described a novel OCT technique to enable assessment of TM motion in living human eyes.…”

Aqueous outflow regulation – 21st century concepts

“…We have unparalleled evidence of physiologic outflow mechanisms provided through in vivo, direct noninvasive, observations of aqueous flow into episcleral veins ( Goldmann, 1946a ) Pulsatile Aqueous Vein Flow Video ( Vid 1 ) 1-s2.0-S1350946220300896-mmc1.mp4 ). A large body of literature documents directly observable evidence of abnormal pulsatile flow in glaucoma ( Ascher, 1942a , 1944 , 1949a; Goldmann, 1948 ; Ascher and Spurgeon, 1949b ; Kleinert, 1951c ; Johnstone et al, 2010 ) ( Fig. 3 ).…”

“…3 ). Ascher and Goldmann, the first clinician-scientists to identify flow into aqueous veins, reported pulsatile flow as a salient feature ( Ascher, 1942a ; Goldmann, 1946a ). Pulsatile outflow originates in SC and is synchronous with the ocular pulse ( Ascher, 1961 ; Johnstone et al, 2010 ).…”

“…Noninvasive aqueous angiography techniques of Ascher explore the normal circumferential distribution of aqueous flow into the episcleral veins on the eye’s surface in healthy humans ( Ascher, 1942a ). Typically, only two or three aqueous veins are visible on the eye’s surface, and a quantitative study indicates that only two such veins can carry all the aqueous flow ( Stepanik, 1954a , 1957 ; Stepanik and Kemper, 1954b ; Ascher, 1961 ).…”

Effect of a fixed combination of ripasudil and brimonidine on aqueous humor dynamics in mice

“…Netarsudil (AR13324), a ROCK inhibitor with norepinephrine transport inhibitory activity, has been reported to lower EVPs in rabbits 32 , and it induces dilation of episcleral vessels in enucleated human eyes, but these effects have been suggested to be mediated mostly by the norepinephrine transport inhibitory activity that causes vasoconstriction 32,33 . The precise mechanisms regulating episcleral circulation remain unclear 34,35 because the interplay between the blood flow and vascular resistance in the episcleral supply arterioles, various arteriovenous anastomoses (AVAs), and muscular veins [36][37][38][39][40][41] is complex. Pharmacologically induced vasodilation and vasoconstriction of the episcleral vasculature can alter the blood flow through AVAs, affecting the EVP, the flow of aqueous into the episcleral veins, and the IOP 40 .…”

Aqueous outflow imaging techniques and what they tell us about intraocular pressure regulation

“…Pulsatile AO was initially reported by Ascher 80 and was thought to originate from SC in synchrony with ocular pulsation. 80,81 The static nature of OCT and OCT-A is a significant limitation when imaging dynamic aspects of the AO system. Li et al 35,82 described a novel OCT technique to enable assessment of TM motion in living human eyes.…”

Aqueous outflow regulation – 21st century concepts

“…We have unparalleled evidence of physiologic outflow mechanisms provided through in vivo, direct noninvasive, observations of aqueous flow into episcleral veins ( Goldmann, 1946a ) Pulsatile Aqueous Vein Flow Video ( Vid 1 ) 1-s2.0-S1350946220300896-mmc1.mp4 ). A large body of literature documents directly observable evidence of abnormal pulsatile flow in glaucoma ( Ascher, 1942a , 1944 , 1949a; Goldmann, 1948 ; Ascher and Spurgeon, 1949b ; Kleinert, 1951c ; Johnstone et al, 2010 ) ( Fig. 3 ).…”

“…3 ). Ascher and Goldmann, the first clinician-scientists to identify flow into aqueous veins, reported pulsatile flow as a salient feature ( Ascher, 1942a ; Goldmann, 1946a ). Pulsatile outflow originates in SC and is synchronous with the ocular pulse ( Ascher, 1961 ; Johnstone et al, 2010 ).…”

“…Noninvasive aqueous angiography techniques of Ascher explore the normal circumferential distribution of aqueous flow into the episcleral veins on the eye’s surface in healthy humans ( Ascher, 1942a ). Typically, only two or three aqueous veins are visible on the eye’s surface, and a quantitative study indicates that only two such veins can carry all the aqueous flow ( Stepanik, 1954a , 1957 ; Stepanik and Kemper, 1954b ; Ascher, 1961 ).…”