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Browsing by Author "Belamkar, Aditya"
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Item Asian Race and Primary Open-Angle Glaucoma: Where Do We Stand?(MDPI, 2022-04-28) Belamkar, Aditya; Harris, Alon; Oddone, Francesco; Verticchio Vercellin, Alice; Fabczak-Kubicka, Anna; Siesky, Brent; Ophthalmology, School of MedicinePrimary open-angle glaucoma (POAG) is an optic neuropathy characterized by irreversible retinal ganglion cell damage and visual field loss. The global POAG prevalence is estimated to be 3.05%, and near term is expected to significantly rise, especially within aging Asian populations. Primary angle-closure glaucoma disproportionately affects Asians, with up to four times greater prevalence of normal-tension glaucoma reported compared with high-tension glaucoma. Estimates for overall POAG prevalence in Asian populations vary, with Chinese and Indian populations representing the majority of future cases. Structural characteristics associated with glaucoma progression including the optic nerve head, retina, and cornea are distinct in Asians, serving as intermediates between African and European descent populations. Patterns in IOP suggest some similarities between races, with a significant inverse relationship between age and IOP only in Asian populations. Genetic differences have been suggested to play a role in these differences, however, a clear genetic pattern is yet to be established. POAG pathogenesis differs between Asians and other ethnicities, and it may differ within the broad classification of the Asian race. Greater awareness and further research are needed to improve treatment plans and outcomes for the increasingly high prevalence of normal tension glaucoma within aging Asian populations.Item Effects of Sex Hormones on Ocular Blood Flow and Intraocular Pressure in Primary Open Angle Glaucoma: A Review(Wolters Kluwer, 2018-10) Patel, Pooja; Harris, Alon; Toris, Carol; Lang, Matthew; Tobe, Leslie; Belamkar, Aditya; Ng, Adrienne; Verticchio Vercellin, Alice C.; Matthew, Sunu; Siesky, Brent; Ophthalmology, School of MedicinePrimary open-angle glaucoma (POAG) is a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and visual field loss. Some speculate that gender plays a role in the risk of developing POAG and that the physiologic differences between men and women may be attributed to the variable effects of sex hormones on intraocular pressure (IOP), ocular blood flow, and/or neuroprotection. Estrogen, in the form of premenopausal status, pregnancy, and post-menopausal hormone therapy is associated with increase in ocular blood flow, decrease in IOP and neuroprotective properties. The vasodilation caused by estrogen and its effects on aqueous humor outflow may contribute. On the other hand, although testosterone may have known effects in the cardiovascular and cerebrovascular systems, there is no consensus as to its effects in ocular health or POAG. With better understanding of sex hormones in POAG, sex hormone-derived preventative and therapeutic considerations in disease management may provide for improved gender-specific patient care.Item Glaucoma Treatment Outcomes in Open-Angle Glaucoma Patients of African Descent(World Scientific, 2022) Siesky, Brent; Harris, Alon; Belamkar, Aditya; Zukerman, Ryan; Horn, Avery; Verticchio Vercellin, Alice; Mendoza, Kristen Ann V.; Sidoti, Paul A.; Oddone, Francesco; Ophthalmology, School of MedicineOpen angle glaucoma (OAG), characterized by structural changes to the optic nerve head and retinal nerve fiber layer, is a progressive multifactorial optic neuropathy and leading cause of irreversible blindness globally. Currently intraocular pressure is the only modifiable risk factor; however, others have been identified including genetics and race. Importantly, OAG is much more prevalent in persons of African descent (AD) compared to those of European descent (ED). OAG patients of AD are also known to have a more severe course of the disease, a finding potentially explained by structural and/or vascular differences within eye tissues. In addition, disparities in treatment outcomes have been identified in OAG patients of AD. Specifically, prostaglandin analogues have been suggested to be more effective in patients of AD than in those ED, while beta-adrenergic receptors have been suggested to be less effective, although the evidence is inconsistent. Being of AD has also been identified as a risk factor for trabeculectomy failure while laser trabeculoplasty, has been conversely found to be very effective in lowering IOP in patients of AD. Alternative surgical options including Ex-Press shunt implantation, viscocanalostomy, and canaloplasty are promising in equivalence but require further research to properly evaluate disparity in outcomes. In addition to treatment outcomes, social disparities affecting clinical care also exist for persons of AD in the form of reduced adherence, access, and choice. Overall, data suggests the need for properly designed prospective trials with AD populations as a primary focus to identify the potential mechanisms driving disparities in treatment and address overall potential bias in glaucoma management.Item Physiology-Enhanced Data Analytics to Evaluate the Effect of Altitude on Intraocular Pressure and Ocular Hemodynamics(MDPI, 2022) Verticchio Vercellin, Alice; Harris, Alon; Belamkar, Aditya; Zukerman, Ryan; Carichino, Lucia; Szopos, Marcela; Siesky, Brent; Quaranta, Luciano; Bruttini, Carlo; Oddone, Francesco; Riva, Ivano; Guidoboni, Giovanna; Ophthalmology, School of MedicineAltitude affects intraocular pressure (IOP); however, the underlying mechanisms involved and its relationship with ocular hemodynamics remain unknown. Herein, a validated mathematical modeling approach was used for a physiology-enhanced (pe-) analysis of the Mont Blanc study (MBS), estimating the effects of altitude on IOP, blood pressure (BP), and retinal hemodynamics. In the MBS, IOP and BP were measured in 33 healthy volunteers at 77 and 3466 m above sea level. Pe-retinal hemodynamics analysis predicted a statistically significant increase (p < 0.001) in the model predicted blood flow and pressure within the retinal vasculature following increases in systemic BP with altitude measured in the MBS. Decreased IOP with altitude led to a non-monotonic behavior of the model predicted retinal vascular resistances, with significant decreases in the resistance of the central retinal artery (p < 0.001) and retinal venules (p = 0.003) and a non-significant increase in the resistance in the central retinal vein (p = 0.253). Pe-aqueous humor analysis showed that a decrease in osmotic pressure difference (OPD) may underlie the difference in IOP measured at different altitudes in the MBS. Our analysis suggests that venules bear the significant portion of the IOP pressure load within the ocular vasculature, and that OPD plays an important role in regulating IOP with changes in altitude.Item Sustained release glaucoma therapies: Novel modalities for overcoming key treatment barriers associated with topical medications(Taylor & Francis, 2022) Belamkar, Aditya; Harris, Alon; Zukerman, Ryan; Siesky, Brent; Oddone, Francesco; Verticchio Vercellin, Alice; Ciulla, Thomas A.; Ophthalmology, School of MedicineGlaucoma is a progressive optic neuropathy and a leading cause of irreversible blindness. The disease has conventionally been characterized by an elevated intraocular pressure (IOP); however, recent research has built the consensus that glaucoma is not only dependent on IOP but rather represents a multifactorial optic neuropathy. Although many risk factors have been identified ranging from demographics to co-morbidities to ocular structural predispositions, IOP is currently the only modifiable risk factor, most often treated by topical IOP-lowering medications. However, topical hypotensive regimens are prone to non-adherence and are largely inefficient, leading to disease progression in spite of treatment. As a result, several companies are developing sustained release (SR) drug delivery systems as alternatives to topical delivery to potentially overcome these barriers. Currently, Bimatoprost SR (DurystaTM) from Allergan plc is the only FDA-approved SR therapy for POAG. Other SR therapies under investigation include: bimatoprost ocular ring (Allergan) (ClinicalTrials.gov identifier: NCT01915940), iDose® (Glaukos Corporation) (NCT03519386), ENV515 (Envisia Therapeutics) (NCT02371746), OTX-TP (Ocular Therapeutix) (NCT02914509), OTX-TIC (Ocular Therapeutix) (NCT04060144), and latanoprost free acid SR (PolyActiva) (NCT04060758). Additionally, a wide variety of technologies for SR therapeutics are under investigation including ocular surface drug delivery systems such as contact lenses and nanotechnology. While challenges remain for SR drug delivery technology in POAG management, this technology may shift treatment paradigms and dramatically improve outcomes.Item Topical carbonic anhydrase inhibitors and glaucoma in 2021: where do we stand?(BMJ Publishing, 2022) Stoner, Ari; Harris, Alon; Oddone, Francesco; Belamkar, Aditya; Verticchio Vercellin, Alice Chandra; Shin, Joshua; Januleviciene, Ingrida; Siesky, Brent; Ophthalmology, School of MedicineCarbonic anhydrase inhibitors (CAIs) have been used for many decades in the treatment of glaucoma. Systemic CAIs were an early treatment option to lower intraocular pressure by reducing aqueous humour production; however, frequent side effects including polyuria and paresthesia contributed to the eventual development of topical CAIs. As topical drug development evolved over time, prostaglandin analogues and beta-blockers have become the gold standard of glaucoma therapies. Although prescribed less often than other classes of topical glaucoma therapies, topical CAIs continue to be used in combination therapies with beta-blockers and alpha agonists. Topical CAIs have also been demonstrated to alter biomarkers of ocular haemodynamics, which have relevance in glaucoma. The purpose of this review is to review and summarise the current state of topical CAI prescribing trends, known efficacy and suggested mechanisms and potential influence on ocular haemodynamics for the future of glaucoma management.