Comment on “global,regional and national patterns in ROP research up to the pre-COVID-19 era: A systematic bibliometric review between 1950 to 2020”

Dear Editor,

We read with great interest the study by Varona et al.. ¹ examined the global, regional, and national patterns of retinopathy of prematurity (ROP) from 1950 to 2020. This systematic bibliometric review provides a critical longitudinal map of scientific production, identifying a marked expansion of the literature following the 1980s. By categorizing nearly 5,000 articles across World Health Organization (WHO) regions and income levels, the authors clarified the profound disparities in knowledge generation. Nevertheless, the clinical and translational implications of these geographical imbalances warrant further analytical scrutiny.

Study design and interpretive framework

The authors utilized a robust bibliometric framework incorporating the compound annual growth rate (CAGR) and citation impact to quantify research evolution. A significant finding is that the Region of the Americas (PAHO) and the European Region (EURO) dominate the landscape, representing over 72% of the total output. However, the study reveals that this productivity is highly localized, with the United States and India driving the majority of the output in their respective regions. From a clinical perspective, this concentration suggests that the prevailing evidence base for ROP, including screening criteria and treatment thresholds, is disproportionately derived from high-income country (HIC) cohorts. To strengthen clinical interpretation, it is essential to consider whether these centralized research models sufficiently account for the “third wave” of ROP observed in lower-middle-income countries (LMICs), where larger, more mature infants often develop severe disease due to variable neonatal oxygen management. ²

Thematic distribution and public health policy

The analysis identified a thematic skew toward risk factors (25.0%) and treatment outcomes (23.5%), while surveillance and public health policies remained marginal (6.3%). The scarcity of policy-oriented research is a critical gap in the translational context. In regions such as sub-Saharan Africa (AFRO), where the study found the lowest publication volume, the lack of locally validated screening protocols represents a significant barrier to preventing childhood blindness. Nevertheless, the transition from clinical observation to health system implementation is necessary to address the increasing incidence of ROP in expanding neonatal intensive care units (NICUs). The near absence of research on population-level strategies in underrepresented regions limits the ability of local stakeholders to formulate evidence-based blindness prevention programs. ²

Citation impact and scientific visibility

The citation analysis highlighted substantial regional inequalities, with PAHO and EURO exhibiting the highest mean citation counts. While the authors correctly identify that these averages are driven by influential “outlier” studies from HICs, this trend perpetuates a cycle of invisibility for LMIC research. When studies from low-resource settings are under-cited or confined to non-indexed platforms, their unique clinical insights, such as ROP presentations in different ethnic or socioeconomic contexts, fail to inform global standards of care. ³

Affirmation of contribution

In conclusion, this review serves as a vital call for action to diversify the global ROP research agenda. This successfully underscores the necessity of strengthening research capacity in LMICs to ensure that the next era of ROP investigation is as geographically inclusive as the disease is pervasive.