We have studied the factors that are important for producing functional retinal neurons from adult derived retinal stem and progenitor cells (RPCs) investigating the role of substrate stiffness or soluble factors in 2D and 3D culture on the differentiation and survival of RPCs. RPCs were cultured on agarose scaffolds modified with the adhesive peptides of varying stiffness. We observed that cell survival in the 0.75% matrix was greater in 3D than in 2D by a factor of 50% irrespective of the time in culture. We observed the presence of photoreceptors exclusively in 0.75% agarose, while the stiffer matrices (1.75%) led to retinal ganglion cell and glial cell differentiation with no significant difference in the differentiation profiles when cells were cultured in 2D vs. 3D. These data indicate that substrate stiffness, more than growth factors, has a significant impact on both the survival and differentiation profile of retinal precursor cells.

We have studied the factors that are important for producing functional retinal neurons from adult derived retinal stem and progenitor cells (RPCs) investigating the role of substrate stiffness or soluble factors in 2D and 3D culture on the differentiation and survival of RPCs. RPCs were cultured on agarose scaffolds modified with the adhesive peptides of varying stiffness. We observed that cell survival in the 0.75% matrix was greater in 3D than in 2D by a factor of 50% irrespective of the time in culture. We observed the presence of photoreceptors exclusively in 0.75% agarose, while the stiffer matrices (1.75%) led to retinal ganglion cell and glial cell differentiation with no significant difference in the differentiation profiles when cells were cultured in 2D vs. 3D. These data indicate that substrate stiffness, more than growth factors, has a significant impact on both the survival and differentiation profile of retinal precursor cells.

Vigabatrin (VGB) is an anti-epileptic drug used to treat children with Infantile Spasms (IS). The 3.0 flicker amplitude of the electroretinogram (ERG) is currently used to monitor visual function changes in infants on VGB. To find a more specific marker of permanent changes due to VGB, sedated ERGs were performed on 31 IS patients and 13 retinally normal controls to isolate components of the cone pathway. ERG growth curves, for each component, recorded from children with IS were generated using data recorded pre-VGB treatment and for controls. Only the cone off response (from Off bipolar cells) and cone photoreceptor sensitivity were associated with decreased flicker amplitude. Twenty nine percent of patients had an abnormal cone off response. No patient had an abnormal cone off response at baseline. No patient with an abnormal cone off response recovered normal function. The cone off response could serve as a marker VGB retinal toxicity.

Vigabatrin (VGB) is an anti-epileptic drug used to treat children with Infantile Spasms (IS). The 3.0 flicker amplitude of the electroretinogram (ERG) is currently used to monitor visual function changes in infants on VGB. To find a more specific marker of permanent changes due to VGB, sedated ERGs were performed on 31 IS patients and 13 retinally normal controls to isolate components of the cone pathway. ERG growth curves, for each component, recorded from children with IS were generated using data recorded pre-VGB treatment and for controls. Only the cone off response (from Off bipolar cells) and cone photoreceptor sensitivity were associated with decreased flicker amplitude. Twenty nine percent of patients had an abnormal cone off response. No patient had an abnormal cone off response at baseline. No patient with an abnormal cone off response recovered normal function. The cone off response could serve as a marker VGB retinal toxicity.

Purpose: To investigate venous total retinal blood flow (TRBF) and retinal blood flow (RBF) in the superior and the inferior retinal hemifields in primary open angle glaucoma (POAG) patients with, and without, disc hemorrhage (DH). Methods: RBF measurements were obtained from 10 POAG with DH and 19 POAG without DH using Doppler SD-OCT (RTVue) as well as bi-directional laser Doppler flowmetry (CLBF). Results: RBF was not different between the superior and inferior hemifields for either of the two groups. Venous TRBF in the POAG with DH group was significantly lower than in the age-matched stable POAG without DH group (p=0.009). In the POAG with DH group, venous TRBF was significantly lower in the DH eye compared to contralateral eye without DH (p=0.015). Conclusions: Venous TRBF was significantly lower in the POAG with DH group compared to both the POAG without DH group and the contralateral eye of the POAG with DH group.

Purpose: To investigate venous total retinal blood flow (TRBF) and retinal blood flow (RBF) in the superior and the inferior retinal hemifields in primary open angle glaucoma (POAG) patients with, and without, disc hemorrhage (DH). Methods: RBF measurements were obtained from 10 POAG with DH and 19 POAG without DH using Doppler SD-OCT (RTVue) as well as bi-directional laser Doppler flowmetry (CLBF). Results: RBF was not different between the superior and inferior hemifields for either of the two groups. Venous TRBF in the POAG with DH group was significantly lower than in the age-matched stable POAG without DH group (p=0.009). In the POAG with DH group, venous TRBF was significantly lower in the DH eye compared to contralateral eye without DH (p=0.015). Conclusions: Venous TRBF was significantly lower in the POAG with DH group compared to both the POAG without DH group and the contralateral eye of the POAG with DH group.

Intraocular pressure (IOP) is the most important risk factor for glaucoma development and progression. Most anti-glaucoma treatments aim to lower IOP by enhancing aqueous humor drainage from the eye. Aqueous humor drainage occurs via well-characterized trabecular meshwork (TM) and uveoscleral (UVS) pathways, and the recently described ciliary lymphatics. The relative contribution of the lymphatic pathway to aqueous drainage is not known. We developed a sheep model to quantitatively assess lymphatic drainage along with TM and UVS outflows. Following intracameral injection of 125I-bovine serum albumin (BSA), lymph and blood samples were continuously collected. Lymphatic and TM drainage were quantitatively assessed by measuring 125I-BSA recovery. This quantitative sheep model enables assessment of relative contributions of lymphatic drainage (1.64% ± 0.89%), TM (68.86% ± 9.27%) and UVS outflows (19.87% ± 5.59%), and may help to better understand the effects of glaucoma agents on outflow pathways.

Intraocular pressure (IOP) is the most important risk factor for glaucoma development and progression. Most anti-glaucoma treatments aim to lower IOP by enhancing aqueous humor drainage from the eye. Aqueous humor drainage occurs via well-characterized trabecular meshwork (TM) and uveoscleral (UVS) pathways, and the recently described ciliary lymphatics. The relative contribution of the lymphatic pathway to aqueous drainage is not known. We developed a sheep model to quantitatively assess lymphatic drainage along with TM and UVS outflows. Following intracameral injection of 125I-bovine serum albumin (BSA), lymph and blood samples were continuously collected. Lymphatic and TM drainage were quantitatively assessed by measuring 125I-BSA recovery. This quantitative sheep model enables assessment of relative contributions of lymphatic drainage (1.64% ± 0.89%), TM (68.86% ± 9.27%) and UVS outflows (19.87% ± 5.59%), and may help to better understand the effects of glaucoma agents on outflow pathways.

Glaucoma is a leading cause of world blindness, often associated with elevated eye pressure. Current glaucoma treatments aim to lower eye pressure by improving aqueous humor outflow from the eye. Ocular lymphatics have been demonstrated to contribute to aqueous humor outflow in human and sheep. It is not known whether any glaucoma drugs target this lymphatic drainage. The mouse is a valuable model with similar aqueous humor dynamics and pharmacology as human. Using in vivo hyperspectral fluorescence imaging combined with intracameral quantum dot injection, we identified an ocular lymphatic drainage in mouse. Immunofluorescence and confocal microscopy revealed lymphatic channels in the ciliary body, sclera, and orbit that may be responsible for this lymphatic drainage. We showed that latanoprost, a prostaglandin F2α analog widely used to treat glaucoma, increases this ocular lymphatic drainage. Our findings provide the framework for future development of novel glaucoma drugs that stimulate the ocular lymphatic drainage.

Glaucoma is a leading cause of world blindness, often associated with elevated eye pressure. Current glaucoma treatments aim to lower eye pressure by improving aqueous humor outflow from the eye. Ocular lymphatics have been demonstrated to contribute to aqueous humor outflow in human and sheep. It is not known whether any glaucoma drugs target this lymphatic drainage. The mouse is a valuable model with similar aqueous humor dynamics and pharmacology as human. Using in vivo hyperspectral fluorescence imaging combined with intracameral quantum dot injection, we identified an ocular lymphatic drainage in mouse. Immunofluorescence and confocal microscopy revealed lymphatic channels in the ciliary body, sclera, and orbit that may be responsible for this lymphatic drainage. We showed that latanoprost, a prostaglandin F2α analog widely used to treat glaucoma, increases this ocular lymphatic drainage. Our findings provide the framework for future development of novel glaucoma drugs that stimulate the ocular lymphatic drainage.