Biometry of primate lenses during immersion in preservation media

Abstract

Purpose: The purpose of this study was to assess the condition of human lenses (obtained from an eye bank) and of fresh monkey lenses, and to determine the effects of maintaining these lenses in various liquid preservation media.

Methods: Freshly excised human and monkey lenses were maintained for 5 h in one of four solutions (Balanced Saline Solution [BSS], Ringer's Solution, Dulbecco's Modified Eagle Medium with Ham's F-12 [DMEM/F-12/F-12], and Tissue Culture Medium 199 [TC-199]) using a custom-designed, temperature-regulated testing cell. A modified optical comparator and digital camera were used to photograph magnified lens profiles and measure lens diameter and thickness. Lens volume was then calculated assuming rotational symmetry about the optical axis.

Results: Seven of the 33 human lenses exhibited extensive swelling and separation of the capsule from the lens cell mass prior to the incubation. During incubation, for 12/22 of the remaining human and 27/27 of the monkey lenses, thickness increased by 1.0-1.8%, diameter decreased by 0.7-1.6% and the volume was essentially unchanged. Substantial swelling and capsular separation were observed in 10 of the 22 human lenses, 7/10 for those maintained in salt solutions, and 3/12 for those in tissue culture media. Lens volumes increased by an average of 6.8%, due to an 8.7% increase in the thickness, while the diameter decreased by 0.9%. These changes appeared to be independent of postmortem time and donor age.

Conclusions: Culture media are more effective than simple salt solutions in maintaining lens physical integrity during short-term incubations. Substantial uptake of water, accompanied by separation of the capsule from the lens cell mass, occurs at various stages during storage and experimental manipulations in >60% of human lenses obtained from the eye bank. Data obtained with such lenses will not be representative of the true ex vivo state. It is recommended that lenses be assessed to determine if swelling has taken place before acceptance of data.