Abstract
Purpose: To develop a technique to assess isotonic solutions for crystalline lens preservation. Methods: BSS, Ringer’s, Dulbecco’s Modified Eagle Medium (DMEM), and TC 199 have been selected for experimentation. Donor human cadaver lenses are extracted by cutting the zonules and vitreous adherences. A custom-made testing cell and modified optical comparator are used for imaging, and the lens diameter and thickness profiles are measured using digital photography and a graphics program. Measurements are taken every 5 minutes for the 1st hour and then every 15 minutes for 4 hrs. The volume of the lens at each interval is approximated, assuming rotational symmetry, by using the equation for the volume of an ellipsoid. The changes in diameter, thickness, and volume versus time are analyzed to compare the effect of each solution. Results: The measurement resolution for the digital technique is 13μm. Lens thickness changed more significantly than diameter and volume. All four solutions produced similar preliminary results with maximum diameter, thickness, and volume changes of approximately -2%, +6%, and +3%, respectively. Conclusion: Shadowphotogrammetry can measure the lens physical dimensions to +/-13um and can be used to determine the effect of preservation media. This technique may be useful for assessing the physical effects of chemical and biological substances on the lens osmotic transport system.
