Glaucoma Treatment Outcomes in Open Angle Glaucoma Patients of African Descent

Open angle glaucoma (OAG), characterized by structural changes to the optic nerve head and retinal nerve fiber layer, is a progressive multifactorial optic neuropathy and a 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 with 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. 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 intraocular pressure in patients of AD. Alternative surgical options, including Ex-Press shunt implantation, viscocanalostomy, and canaloplasty are promising in equivalence but require further research to evaluate disparity in outcome properly. In addition to treatment outcomes, social disparities affecting clinical care also exist for AD persons in the form of reduced adherence, access, and choice. Overall, data suggest 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.

Differences in ocular blood flow in glaucoma between patients of African and European descent

PURPOSE

To investigate differences in ocular blood flow in individuals of African descent (AD) and European descent (ED) with open angle glaucoma (OAG).

PATIENTS AND METHODS

A retrospective data analysis was performed on OAG patients of AD and ED who were previously examined for ocular blood flow within the Department of Ophthalmology at Indiana University School of Medicine. Data analysis included blood pressure, heart rate, visual fields, intraocular pressure, ocular perfusion pressure, and color Doppler imaging of retrobulbar vessels. Color Doppler imaging measurements were performed on ophthalmic, central retinal, and nasal and temporal short posterior ciliary arteries, with peak systolic (PSV) and end diastolic velocities (EDV) as well as the Pourcelot vascular resistive index calculated for each vessel. Two-sample t tests of unequal variance were performed with P values <0.05 considered statistically significant.

RESULTS

OAG patients of AD had statistically significant lower retrobulbar blood flow values than patients of ED including lower ophthalmic artery PSV (P=0.0001), ophthalmic artery EDV (P=0.0008), central retinal artery PSV (P=0.01), temporal short posterior ciliary artery PSV (P=0.0037), and nasal short posterior ciliary artery PSV (P<0.0001). No significant differences were found in terms of intraocular pressure or visual field parameters.

CONCLUSIONS

Significantly lower blood flow values were identified in all retrobulbar blood vessels in AD compared with ED OAG patients. These findings suggest that the contribution of ocular blood flow to the disease process may be different in AD compared with ED OAG patients.

Genetic susceptibility to prostate cancer in men of African descent: implications for global disparities in incidence and outcomes

INTRODUCTION

Disparities in prostate cancer incidence and outcomes are a hallmark of the global pattern of prostate cancer, with men of African descent suffering disproportionately from this disease. The causes of these disparities are poorly understood.

METHODS

A review of the literature was undertaken to evaluate the role that genetic susceptibility may play in prostate cancer etiology and outcomes, with a particular emphasis on disparities.

RESULTS

The genetic contribution to prostate cancer is well established, and a number of candidate prostate cancer genes have been identified. Significant differences in the frequency of risk alleles in these genes have been identified across the major races. These allele frequency differences may in part explain an increased susceptibility to prostate cancer in some populations. In addition, non-genetic factors contribute significantly to prostate cancer disparities, and the cumulative contribution of both genetic and non-genetic factors to poor-prognosis prostate cancer may explain the poorer outcomes experienced by men of African descent.

CONCLUSIONS

Prostate cancer disparities are a function of genetic susceptibility as well as environment, behavior, and health care factors acting in the context of this genetic susceptibility. Elimination of global prostate cancer disparities requires a full understanding of the effects of all of these factors on prostate cancer etiology and outcomes.