Risk factors for structural and functional progression of primary open-angle glaucoma in an African ancestry cohort

BACKGROUND/AIMS

To investigate the rates of structural and functional progression of primary open-angle glaucoma in an African ancestry cohort and identify risk factors for progression.

METHODS

This retrospective study included 1424 eyes from glaucoma cases in the Primary Open-Angle African American Glaucoma Genetics cohort, with ≥2 visits for retinal nerve fibre layer (RNFL) thickness and mean deviation (MD) measurements over ≥6-month follow-up. The rates of structural progression (change in RNFL thickness/year) and functional progression (change in MD/year) were calculated from linear mixed effects models, accounting for intereye correlation and longitudinal correlation. Eyes were categorised as slow, moderate or fast progressors. Risk factors for progression rates were assessed using univariable and multivariable regression models.

RESULTS

The median (interquartile) rates of progression were -1.60 (-2.05 to -1.15) µm/year for RNFL thickness and -0.40 (-0.44 to -0.34) decibels/year for MD. Eyes were categorised as slow (structural: 19%, functional: 88%), moderate (structural: 54%, functional: 11%) and fast (structural: 27%, functional: 1%) progressors. In multivariable analysis, faster RNFL progression was independently associated with thicker baseline RNFL (p<0.0001), lower baseline MD (p=0.003) and beta peripapillary atrophy (p=0.03). Faster MD progression was independently associated with higher baseline MD (p<0.0001), larger cup-to-disc ratios (p=0.02) and lower body mass index (p=0.0004).

CONCLUSION

The median rates of structural and functional progression in this African ancestry cohort were faster than the rates reported from previously published studies in other ethnic groups. Higher baseline RNFL thickness and MD values were associated with faster progression rates. Results highlight the importance of monitoring structural and functional glaucoma progression to provide timely treatment in early disease.

Ocular and Systemic Factors Associated with Glaucoma

Glaucoma is one of the leading causes of irreversible blindness in the world. Although numerous factors have been implicated in the pathogenesis of glaucoma, the main focus of management still remains lowering the intraocular pressure (IOP) by medical or surgical therapy. However, a major challenge is that many glaucoma patients continue to progress despite good control of IOP. In this regard, the importance of other coexisting factors that may contribute to disease progression needs to be explored. Ophthalmologists need to be aware of ocular risk factors and the impact of systemic diseases and their medications, along with lifestyle modifications on the course of glaucomatous optic neuropathy and adopt a holistic approach in treating the eye as well as the patient to alleviate the suffering from glaucoma in a comprehensive manner.

How to cite this article

Dada T, Verma S, Gagrani M, et al. Ocular and Systemic Factors associated with Glaucoma. J Curr Glaucoma Pract 2022;16(3):179-191.

Dietary Nitrate Intake Is Associated with Decreased Incidence of Open-Angle Glaucoma: The Rotterdam Study

Previous studies suggest that nitric oxide is involved in the regulation of the intraocular pressure (IOP) and in the pathophysiology of open-angle glaucoma (OAG). However, prospective studies investigating the association between dietary nitrate intake, a source of nitric oxide, and incident (i)OAG risk are limited. We aimed to determine the association between dietary nitrate intake and iOAG, and to evaluate the association between dietary nitrate intake and IOP. From 1991 onwards, participants were followed each five years for iOAG in the Rotterdam Study. A total of 173 participants developed iOAG during follow-up. Cases and controls were matched on age (mean ± standard deviation: 65.7 ± 6.9) and sex (%female: 53.2) in a case:control ratio of 1:5. After adjustment for potential confounders, total dietary nitrate intake was associated with a lower iOAG risk (odds ratio (OR) with corresponding 95% confidence interval (95% CI): 0.95 (0.91-0.98) for each 10 mg/day higher intake). Both nitrate intake from vegetables (OR (95% CI): 0.95 (0.91-0.98) for each 10 mg/day higher intake) and nitrate intake from non-vegetable food sources (OR (95% CI): 0.63 (0.41-0.96) for each 10 mg/day higher intake) were associated with a lower iOAG risk. Dietary nitrate intake was not associated with IOP. In conclusion, dietary nitrate intake was associated with a reduced risk of iOAG. IOP-independent mechanisms may underlie the association with OAG.