RA - orphan posts | Video Desmetocele from Neurotropic Ulcer (Photo) Timothy Root, MD This slit-lamp photograph demonstrates thinning of the central cornea from a neurotropic ulcer. The slit-lamp beam can give you an idea of corneal integrity. You can see that right in the middle of this lesion the beam becomes very tight … probably 25% normal thickness.The central area is so clear because it is thin. Practically a desmetocele that eventually perforated.