Although I-131 is relatively safe, there is limited focus on probable eye-related side effects after radioactive iodine (RAI) therapy. Thus, we aimed to provide evidence for the adverse outcomes of I-131, exclusively in thyroid cancer patients.

A systematic review based on the PRISMA guidelines was designed to examine the ocular complications of RAI therapy. Databases including PubMed, Scopus and Web of Science were searched until October 2023 with specific MeSH terms. After thorough screening and review, relevant data were extracted.

The database search yielded 3,434 articles, which resulted in the final 28 eligible studies. These studies investigated ophthalmic symptoms following RAI therapy, classifying them as obstructive diseases (e.g., nasolacrimal duct obstruction [NLDO; median incidence rate: 6.8%]), inflammatory symptoms (median incidence rate: 13%), and cataracts (median incidence rate: 2.5 and 5%). The most common time interval between RAI therapy and the onset of symptoms was within the first 12 months and then declined in the preceding years. A strong positive correlation was observed between higher I-131 doses of more than 100-150 mCi (3.7-5.55 GBq) and the risk of symptom development. Ages older than 45 also showed a significant association with NLDO.

The risk of ophthalmic complications is associated with various factors, including the administration of high I-131 doses, age of more than 45 years, and time to event within the first 12 months. Considering these conditions may help enhance patient care and prevent adverse outcomes that may limit patients’ quality of life.