https://www.selleckchem.com/products/sbfi-26.html Indian Journal of Ophthalmology, Eye, and Graefe's Archive for Clinical and Experimental Ophthalmology were sources with greatest number of research items. Documents per author were 0.257 and authors per document were 3.89. The collaboration index was noted to be 4.28. Our scientometric analysis presents descriptive quantitative metrics for COVID-related research in the field of ophthalmology and provides evidence for the increased global collaboration that global researchers have fostered to fight this pandemic. Our scientometric analysis presents descriptive quantitative metrics for COVID-related research in the field of ophthalmology and provides evidence for the increased global collaboration that global researchers have fostered to fight this pandemic. To describe methods of risk assessment in twins with retinoblastoma (RB). A case series of four RB probands with a twin sibling. Family status, clinical presentation, and RB1 germline status-based risk assessment were analyzed. Two pairs had a positive family history (unilateral and bilateral RB in one of the parents (#1 and #2, respectively) and two pairs (#3 and #4) were sporadic. One of the familial twins (#1) had a high risk (90%) of manifesting RB in the twin. The other case (#2) with an absent RB1 germline mutation in the twin had a 0% risk of developing RB. Among sporadic cases of twins (#3), genetic testing did not identify a germline mutation (tumor sample unavailable) in the proband which downgraded the risk of germline mutation from 15% to <1%. The twin never developed RB (5 years of age at last follow-up). Pathogenic mosaicism for germline RB1 mutation (c.1723C>T) could be identified (tumor tissue available) in the proband (# 4). Identical germline mutation (and RB tumor) was also noted in the twin. In each case, there was concordance between the assessed risk and manifestation of RB. Assessment of risk of RB in a twin presents with a unique challenge.