LAUSR

To the Editor: We read with great interest the article by Mazzotta et al.1 It is highly commendable to have a 10-year-long follow-up after an intervention; however, there is a lack of clarity regarding certain statements in the discussion. At one point, the authors mentioned that repeat corneal collagen cross-linking (CXL) was required in 2 patients, 24 to 36 months after the first procedure, due to Kmax (maximum K) progression. However, they have contradicted this by stating that repeat CXL was required in 2 patients between the seventh and 10th year of follow-up. Also, the authors have not classified the study population based on the severity of keratoconus, which, although it significantly influences the amount of flattening after CXL, is not known to correlate with the postoperative visual acuity.2,3 Also, other than for the 2 patients requiring repeat CXL, the authors have not mentioned the history of allergic conjunctivitis in the remaining subjects. This is of significance as the long-term role of concurrent allergic pathology in the setting of keratoconus and its interplay with CXL is yet to be clearly elucidated.4,5 And so, it would have been desirable to elicit this history in greater detail and note its effect on progression following CXL. It would have also been desirable to study the severity of the coexisting allergy and its correlation with the grade of keratoconus. Furthermore, the time interval between the diagnosis of keratoconus and performing CXL has not been mentioned, which may help us to understand the optimal time to intervene in such cases.