This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
[{'content': "What is a percentage of endothelial cell loss during Descemet's stripping automated endothelial keratoplasty – \nSelect and explain. \nA. 0 – 5%, B. 10 – 20%, C. 30 – 40%, D. 50 – 60%", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Endothelial cell loss is a known phenomenon of endothelial keratoplasty (including DSAEK).\nI am not sure about the answer as various studies have given different values at a different time (post-operatively).\nFirst read following statements which are supporting my answer:-\n\n"Current modifications of EK such as DSAEK have shown a significantly higher cell loss at just 6-12 months after DSAEK surgery".\n\n–Corneal endothelial transplant\n\n"Reports of endothelial cell loss have been very variable from as high as 50% at 6 months to 26% after 2 years in the Busin series. Other reports suggest that there is no difference between cell loss with a 40% loss at 1 year for both PLK and PK and a recent study comparing endothelial cell loss in historic PK Vs DSAEK or other PLK techniques showed no measurable difference".\n\n–Cornea & External eye disease\n\n"The 12-month cell loss for 2 diagnoses (Pseudophakic/aphakic corneal edema and Fush\'s dystrophy) was comparable, i.e. 41% and 37%.\n\n–Internet\n\n"One-year endothelial cell loss after DSAEK is 15 - 40% (average 27%)".\n\n—XXIV Annual Meeting European Eye Bank Association\n\n"There have been several publications showing endothelial cell loss to be in the range of 24-50% at 12-24 months post DSAEK".\xa0\n\nNow read the statements, which have different values at different post-operative period:\n\n"The 1, 3, and 5-year endothelial cell losses derived from the models after DSAEK were 56%, 66%, and 73%, respectively and after THPK were 24%, 50% and 64% respectively".\xa0\n"The 5-year endothelial cell loss after DSEK compared favourably with that measured after penetrating Keratoplasty in the cornea donor study (53% Vs 70%)".\n"At 1-year post DSAEK, Bahar et al. published 36% cell loss, Busin et al. reported 24% cell loss; Covert and Koening published 57% and Gorovoy et al. 40%. At 2 years, the rate of endothelial cell loss is between 41% (Price & Price) and 36% (Terry et al).\xa0\n\nHowever, amongst the given options, option \'c\' fits best in all the data mentioned above.', 'role': 'assistant'}]