The Effect Of High And Low Molecular Weight Sodium Hyaluronic Acid Eye Drops After Crosslinking

CCM was performed using the Heidelberg Retinal Tomograph 3 with the Rostock Cornea Module (HRT3-RCM, Heidelberg Engineering GmbH, Germany) under topical anesthesia. A viscous gel (Viscotears, Novartis Pharmaceuticals UK) served as a coupling agent between the cornea and the applanation cap. The subjects were instructed to focus on the fixation light with the unexamined eye to ensure proper positioning. Five high-quality images of the SNP were selected and analyzed using the automated tracing of nerve fibers program (ACCMetrics, M.A. Dabbah, Imaging Science and Biomedical Engineering, Manchester, England).

Corneal sensitivity was evaluated using a Cochet-Bonnet esthesiometer (Luneau Ophtalmologue, Chartres, France), comprising a nylon filament measuring 60 mm in length and 0.12 mm in diameter. Participants were instructed to maintain a forward gaze while the esthesiometer gently made perpendicular contact. The procedure involved gradually decreasing the filament length in 5 mm increments, starting from 60 mm, until the initial response from the subject was detected.

Noninvasive tear break-up time (NI-TBUT) was assessed using a Sirius Scheimpflug camera (CSO, Florence, Italy) and the device automatically provided the average NI-TBUT value

The Ocular surface disease index (OSDI) questionnaire consists of a total of 12 questions categorized into three subscales as follows: ocular symptoms, vision-related function, and environmental triggers. Each patient is asked to rate the symptoms on a 5-point scale ranging from never (0 score) to always (4 score) for every question in the questionnaire. The fourth and fifth questions in the first section, concerning blurred vision and reduced vision symptoms, were excluded from the questionnaire as these symptoms may already be present in patients with keratoconus disease. The total OSDI score was calculated according to the formula: OSDI = \[(sum of scores for all questions answered) × 100\] / \[(total number of questions answered) × 4\].

Scheimpflug-tomography device (Pentacam, OCULUS, Wetzlar, Germany) was used for measurement of keratometric values.