Previously treated with CLET patients are included retrospectively, as the follow-up procedure is already stablished in our centre, and patients treated following standard care or through "drugs-in-special-situation" request in Spain prospectively. Patients are not treated to be included in the study, only the follow-up variables are taken into account.

The SIDEQ gives a 0-4 score about the presence of dryness, foreign body sensation, burning/stinging, pain, itching, sensitivity to light, and blurred vision, where higher scores indicate higher intensity of the symptom (maximun score: 28). One of the primary outcomes for this work is the improvement in any of the four questionnaires shown here.

The OSDI evaluates ocular surface symptoms with 12 questions, and scores >12 indicate abnormal symptomatology, and >32 means severe symptoms (maximum score 100). One of the primary outcomes for this work is the improvement in any of the four questionnaires shown here.

The visual function-related aspects of the quality of life were evaluated with the NEI-VFQ25, where higher scores on a 0 to 100 scale indicate better function. One of the primary outcomes for this work is the improvement in any of the four questionnaires shown here.

The CDES-Q evaluates ocular surface symptoms with two questions, CDES-Q1 and CDES-Q2. CDES-Q1 evaluates the change in symptoms occured since the previous examination (same, better or worse). CDES-Q2 evaluates the magnitude of the change in a scale from 0 to 10, where 0 means "slightly better/worse" and 10 means "extremely better/worse". One of the primary outcomes for this work is the improvement in any of the four questionnaires shown here.