Geographical disparities in visual acuity at diagnosis among patients with neovascular age-related macular degeneration

Age-related macular degeneration (AMD) is an eye disease affecting approximately 8% of individuals aged ≥ 50 years globally, and is the leading cause of irreversible visual impairment and blindness in the Global North [1]. Age is the greatest risk factor for developing AMD, and its incidence triples per decade after the age of 50 years [2]. Thus, prevalence is expected to increase due to ageing populations [3, 4]. AMD is characterised by degenerative changes in the retina, predominantly in the macula, that affect neural, structural and vascular layers [5]. There are no approved treatments for AMD in Denmark before it reaches the late neovascular form (nAMD), though Age-Related Eye Disease Study (AREDS)-2 supplements are recommended in intermediate AMD. nAMD is characterised by the presence of new macular blood vessels, where vascular endothelial growth factor A (VEGF-A) is a key driver [5]. nAMD is treated with repeated intravitreal anti-VEGF injections, which inhibit the development of neovascularisation and leakage that lead to visual impairment. Best corrected visual acuity (BCVA) at nAMD diagnosis is important for prognosis, as it establishes a maximum for expected effects of treatment with anti-VEGF antibodies [6]. As a result, early diagnosis and treatment are important for preserving vision [7]. However, studies show that diagnosis is often made after visual acuity has decreased markedly, with one study finding a median BCVA at diagnosis in nAMD patients starting anti-VEGF treatment of 55 Early Treatment of Diabetic Retinopathy Study (ETDRS) letters and another finding a mean BCVA of 57 letters [8, 9]. Inequality in health persists as a challenge in Denmark [10]. This also applies to eye health, with unequal distribution of eye diseases by ethnicity, biological sex, socioeconomic status and age. A recent Danish study reported an association between socioeconomic factors, including education and household income, and a diagnosis of cataract and glaucoma [11]. In addition, studies conducted in the United States found geographical disparity in a range of eye diseases and decreased BCVA [10, 12]. Similarly, a Danish study identified significant disparity in diabetic retinopathy across postal codes in a geographically limited area around Aarhus [13]. Nonetheless, geographical disparities in BCVA among patients with nAMD remain understudied despite their importance in prognosis. This study aimed to investigate geographical disparities in BCVA at the time of nAMD diagnosis among patients residing in Region Zealand, Denmark, and to examine potential sex differences in diagnostic presentation.