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This Article Full Text Full Text (PDF) All Versions of this Article: 294/6/C1430    most recent 90623.2007v2 90623.2007v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Zamudio, A. C. Articles by Gerometta, R. PubMed PubMed Citation Articles by Zamudio, A. C. Articles by Gerometta, R.

MEMBRANE TRANSPORTERS, ION CHANNELS, AND PUMPS

Surface change of the mammalian lens during accommodation

Departments of ¹Ophthalmology and ²Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York; and ³Oftalmología, Universidad Nacional del Nordeste, Corrientes, Argentina

Submitted 13 December 2007 ; accepted in final form 2 April 2008

Classical theories suggest that the surface area of the crystalline lens changes during accommodation while the lens volume remains constant. Our recent work challenged this view by showing that the lens volume decreases as the lens flattens during unaccommodation. In this paper we investigate 1) the magnitude of changes in the surface of the in vitro isolated cow lens during simulated accommodation, as well as that of human lens models, determined from lateral photographs and the application of the first theorem of Pappus; and 2) the velocity of the equatorial diameter recovery of prestretched cow and rabbit lenses by using a custom-built software-controlled stretching apparatus synchronized to a digital camera. Our results showed that the in vitro cow lens surface changed in an unexpected manner during accommodation depending on how much tension was applied to flatten the lens. In this case, the anterior surface initially collapsed with a reduction in surface followed by an increase in surface, when the stretching was applied. In the human lens model, the surface increased when the lens unaccommodated. The lens volume always decreases as the lens flattens. An explanation for the unexpected surface change is presented and discussed. Furthermore, we determined that the changes in lens volume, as reflected by the speed of the equatorial diameter recovery in in vitro cow and rabbit lenses during simulated accommodation, occurred within a physiologically relevant time frame (200 ms), implying a rapid movement of fluid to and from the lens during accommodation.

lens surface area calculation; lens volume calculation; lenticular fluid movement; in vitro model for accommodation