Aqueous Humor Dynamics in Pigment Dispersion Syndrome

Abstract

Objective: To assess aqueous humor dynamics in pigment dispersion syndrome (PDS). Methods: Four groups of age-matched participants included 2 experimental groups with PDS (PDS with ocular hypertension [PDS-OHT], 17 eyes; PDS without ocular hypertension [PDS-ONT], 18 eyes) and 2 control groups without PDS (OHT, 18 eyes; ONT, 18 eyes). Assessments included intraocular pressure measured by pneumatonometry, episcleral venous pressure by venomanometry, aqueous flow and outflow facility by fluorophotometry, corneal thickness and anterior chamber depth by pachymetry, and uveoscleral outflow by mathematical calculation. Comparisons were made by analysis of variance and 2-tailed unpaired t tests. Results: The PDS-OHT group had higher intraocular pressures than the ONT and PDS-ONT groups (PϽ.001) and higher episcleral venous pressure (P=.04) and lower outflow facility (P=.01) than the ONT group. Anterior chamber volume was larger in the PDS-OHT group than in the other groups (PϽ .05 for all). No other comparisons between the PDS-OHT group and the other groups yielded statistically significant differences at a significance level of less than .05. Conclusions: The elevated intraocular pressure in PDS is caused by reduced outflow facility. This differs from OHT without PDS, in which reductions in uveoscleral outflow and outflow facility have been reported.

Iris Microcirculation After Selective Laser Trabeculoplasty: A Pilot Optical Coherence Tomography Angiography Study

“…However, except for a single study that showed shallow ciliochoroidal detachment after STL using ultrasound biomicroscopy, there are no data supporting changes in the ciliary body after SLT [ 20 ]. Certain types of anterior uveitis (such as those related to HLA B-27) may present with acute hypotony possibly due to the increase in uveoscleral outflow or aqueous production decrease [ 21 , 22 ]. Although anterior segment inflammation may cause a transient decrease in IOP, it would not influence long-term outcomes of SLT since inflammation and transitory IOP reduction regress a few days after SLT.…”

Iris Microcirculation After Selective Laser Trabeculoplasty: A Pilot Optical Coherence Tomography Angiography Study

“…However, except for a single study that showed shallow ciliochoroidal detachment after STL using ultrasound biomicroscopy, there are no data supporting changes in the ciliary body after SLT [ 20 ]. Certain types of anterior uveitis (such as those related to HLA B-27) may present with acute hypotony possibly due to the increase in uveoscleral outflow or aqueous production decrease [ 21 , 22 ]. Although anterior segment inflammation may cause a transient decrease in IOP, it would not influence long-term outcomes of SLT since inflammation and transitory IOP reduction regress a few days after SLT.…”

Intraluminal Suture Placement for Management of Hypotony After Glaucoma Drainage Device Surgery

“…Of the 9 eyes in this study, 5 (55.6%) had glaucoma secondary to uveitis. Uveitis may lead to IOP elevation due to many mechanisms; however, inflammation of the ciliary body or atrophy of the ciliary epithelium may also result in aqueous hyposecretion 20 . Hyposecretion secondary to anterior segment inflammation may contribute to the hypotony developing months after GDD implantation, where insertion of a 3-0 Supramid stent was found to be beneficial.…”

Ocular morphologic traits in the American Cocker Spaniel may confer primary angle closure glaucoma susceptibility

“…Additionally, it corroborates the increased expression of COX-2 in trabecular meshwork, angular aqueous plexus and ciliary body of glaucomatous dog eyes and increased VEGF concentration in aqueous humor of dogs affected with primary glaucoma 31 , 32 . Indeed, uveoscleral outflow was also more enhanced in humans affected with pigment dispersion syndrome to compensate for the pigment dispersion process compromising the trabecular outflow facility and to maintain a normal IOP 33 . Thus, measurement of uveoscleral outflow facility and sampling of aqueous humor to measure inflammatory mediators in the ACS might help explain the underlying mechanism of lower normal IOPs in this breed in comparison to the Beagle.…”

Iris Microcirculation After Selective Laser Trabeculoplasty: A Pilot Optical Coherence Tomography Angiography Study

“…However, except for a single study that showed shallow ciliochoroidal detachment after STL using ultrasound biomicroscopy, there are no data supporting changes in the ciliary body after SLT [ 20 ]. Certain types of anterior uveitis (such as those related to HLA B-27) may present with acute hypotony possibly due to the increase in uveoscleral outflow or aqueous production decrease [ 21 , 22 ]. Although anterior segment inflammation may cause a transient decrease in IOP, it would not influence long-term outcomes of SLT since inflammation and transitory IOP reduction regress a few days after SLT.…”

Intraluminal Suture Placement for Management of Hypotony After Glaucoma Drainage Device Surgery

“…Of the 9 eyes in this study, 5 (55.6%) had glaucoma secondary to uveitis. Uveitis may lead to IOP elevation due to many mechanisms; however, inflammation of the ciliary body or atrophy of the ciliary epithelium may also result in aqueous hyposecretion 20 . Hyposecretion secondary to anterior segment inflammation may contribute to the hypotony developing months after GDD implantation, where insertion of a 3-0 Supramid stent was found to be beneficial.…”

Ocular morphologic traits in the American Cocker Spaniel may confer primary angle closure glaucoma susceptibility

“…Additionally, it corroborates the increased expression of COX-2 in trabecular meshwork, angular aqueous plexus and ciliary body of glaucomatous dog eyes and increased VEGF concentration in aqueous humor of dogs affected with primary glaucoma 31 , 32 . Indeed, uveoscleral outflow was also more enhanced in humans affected with pigment dispersion syndrome to compensate for the pigment dispersion process compromising the trabecular outflow facility and to maintain a normal IOP 33 . Thus, measurement of uveoscleral outflow facility and sampling of aqueous humor to measure inflammatory mediators in the ACS might help explain the underlying mechanism of lower normal IOPs in this breed in comparison to the Beagle.…”

Iris Microcirculation After Selective Laser Trabeculoplasty: A Pilot Optical Coherence Tomography Angiography Study

“…However, except for a single study that showed shallow ciliochoroidal detachment after STL using ultrasound biomicroscopy, there are no data supporting changes in the ciliary body after SLT [ 20 ]. Certain types of anterior uveitis (such as those related to HLA B-27) may present with acute hypotony possibly due to the increase in uveoscleral outflow or aqueous production decrease [ 21 , 22 ]. Although anterior segment inflammation may cause a transient decrease in IOP, it would not influence long-term outcomes of SLT since inflammation and transitory IOP reduction regress a few days after SLT.…”

Intraluminal Suture Placement for Management of Hypotony After Glaucoma Drainage Device Surgery

“…Of the 9 eyes in this study, 5 (55.6%) had glaucoma secondary to uveitis. Uveitis may lead to IOP elevation due to many mechanisms; however, inflammation of the ciliary body or atrophy of the ciliary epithelium may also result in aqueous hyposecretion 20 . Hyposecretion secondary to anterior segment inflammation may contribute to the hypotony developing months after GDD implantation, where insertion of a 3-0 Supramid stent was found to be beneficial.…”

Ocular morphologic traits in the American Cocker Spaniel may confer primary angle closure glaucoma susceptibility

“…Additionally, it corroborates the increased expression of COX-2 in trabecular meshwork, angular aqueous plexus and ciliary body of glaucomatous dog eyes and increased VEGF concentration in aqueous humor of dogs affected with primary glaucoma 31 , 32 . Indeed, uveoscleral outflow was also more enhanced in humans affected with pigment dispersion syndrome to compensate for the pigment dispersion process compromising the trabecular outflow facility and to maintain a normal IOP 33 . Thus, measurement of uveoscleral outflow facility and sampling of aqueous humor to measure inflammatory mediators in the ACS might help explain the underlying mechanism of lower normal IOPs in this breed in comparison to the Beagle.…”