Benoxinate hydrochloride

Participants were examined using a Heidelberg Retina Tomograph-3 equipped with a Rostock Cornea Module (Heidelberg Engineering, Heidelberg, Germany)12 ,13 . The examined eye was anesthetized by instilling 0.4% benoxinate hydrochloride (Santen Pharmaceutical Co., Osaka, Japan). Comfort Gel (Dr. Mann Pharma, Berlin, Germany) was applied to the lens, and a disposable sterilized Tomocap was mounted on the holder to cover the objective lens. After applying Comfort Gel to the Tomocap, the lens was slowly advanced until the gel touched the cornea. More than 50 images of the subbasal nerve plexus were captured using the section mode, and we analyzed at least six high-clarity images per participant to quantify the following parameters to define changes in the corneal C fiber: (i) corneal nerve fiber density/mm² (CNFD); (ii) corneal nerve fiber length mm/mm² (CNFL); (iii) corneal nerve branch density/mm² (CNBD); (iv) corneal nerve branch length mm/mm² (CNBL) emanating from the major nerves; (v) tortuosity grade (TG); and (vi) frequency/0.1 mm of beading (BF). The TG was measured using the grading system of Oliveira-Soto and Efron14 (link); all other measurements were carried out using ImageJ (Texelcraft, Tokyo, Japan).