how to measure hvid
1. CORNEAL DIAMETER- HVID OPTOM FASLU MUHAMMED. 2. ï¨ Technique 1: ï¨ Corneal Topographer :use the biometric ruler within the corneal topography software program to measure your patientâs horizontal visible iris diameter (HVID). ï¨ It may be necessary to measure at a 45 degree oblique angle as the topographer may cut off part of the cornea in the horizontal plane.