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  • Cornea/External Disease

    Review of: Global trends in blindness and vision impairment due to corneal opacity 1984–2020: A meta-analysis

    Wang E, Kong X, Wolle M, et al. Ophthalmology, in press 2023

    A large-scale literature analysis reveals that corneal opacity–related vision loss continues to be a major global issue and disproportionately impacts regions that are least equipped to manage corneal diseases.

    Study design

    A systematic literature search analyzed corneal opacity vision impairment data from population-based surveys for subjects more than 40 years of age to determine the global burden. A total of 244 studies encompassing 73 countries and nearly 2 million individuals were included in addition to abstracted data from the Global Burden of Disease Vision Loss Expert Group.


    Roughly 5.5 million individuals over the age of 40 are estimated to have bilateral vision loss worse than 20/60 secondary to corneal opacities. An additional 6.2 million are estimated to have unilateral blindness. While corneal opacity blindness due to trachoma appears to be declining, large disparities in the prevalence rates of corneal opacity visual impairment overall persist around the globe, with Africa/Middle East showing 8–14 times higher rates than other regions.


    The large-scale nature of the meta-analysis presents several limitations. Because studies varied in how they categorized countries, and larger regions had to be compiled for statistical analysis, skewing of the data may have been introduced. Countries within a particular region defined by this study may not be any more homogenous than countries that were placed in separate regions. Additionally, due to the lack of studies from North America, extrapolated data from the rest of the world were used to establish global trends, which may not be an accurate North American representation.

    Clinical significance

    This paper highlights the importance of continued global health initiatives and innovation in the field of corneal surgery. Given the scarcity of corneal transplant tissue from a global perspective, with only 1 donor tissue available for every 70 eyes,1 public health initiatives to improve nutrition, reduce infectious disease, and increase access to healthcare remain the foundation for reducing corneal blindness. Furthermore, this study highlights the need for continued support of international fellowships and training programs to increase the number of providers and eye banking in disproportionately burdened regions.

    Financial Disclosures: Dr. Daniel Choi discloses financial relationships with Glaukos Corporation (Lecture Fees/Speakers Bureau); Kala Pharmaceuticals (Consultant/Advisor).


    1 Gain P et al. JAMA Ophthalmology. 2016;134(167-173).