Subject(s)
Disease Management , Eyeglasses , Refraction, Ocular/physiology , Refractive Errors/therapy , Female , Humans , Infant , Male , Refractive Errors/physiopathology , Vision TestsABSTRACT
PURPOSE: To study the effect of trypan blue on lens capsule elasticity and ease of completing a continuous curvilinear capsulorhexis (CCC) in a sheep lens model and to subsequently observe the effects of trypan blue in the surgical setting of 3 pediatric patients. SETTING: State University of New York, Downstate Medical Center, Brooklyn, New York, USA. DESIGN: Prospective case series. METHODS: Twenty-four lenses were excised from fresh sheep globes. Twelve lenses were immersed in trypan blue for 2.5 minutes, and 12 lenses were immersed in a balanced salt solution for 2.5 minutes. Ease of completion of CCC was graded, and intralenticular pressure was quantified. A pediatric cataract surgeon used trypan blue to stain the lens capsules of 3 children during cataract surgery. The surgeon noted the effects of trypan blue on capsule elasticity and on the ease of completion of the CCC. RESULTS: Lenses immersed in trypan blue had a mean score of 2.58 in ease of completion of capsulorhexis compared with the control group (1.5) (P = .031). Capsulorhexis was successfully completed in 91.7% of trypan blue cases compared with 58.3% of controls. Immersion in trypan blue decreased the intralenticular pressure by a mean of 4.5 mm Hg (P = .025). Successful capsulorhexis was completed in the 3 pediatric cases. CONCLUSION: Trypan blue improved the success rate of CCC completion in the sheep lens by decreasing lens capsule elasticity. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.
Subject(s)
Capsulorhexis/methods , Coloring Agents/therapeutic use , Trypan Blue/therapeutic use , Animals , Cataract , Child , Humans , Models, Animal , Prospective Studies , Staining and LabelingSubject(s)
Conservation of Natural Resources/methods , Ecosystem , Federal Government , Transportation/instrumentation , Urbanization , Animal Migration , Animals , Biodiversity , Environmental Pollution/prevention & control , Food Chain , Models, Economic , Politics , Risk Assessment , Ruminants/physiology , TanzaniaABSTRACT
Sexual competition is associated closely with parental care because the sex providing less care has a higher potential rate of reproduction, and hence more to gain from competing for multiple mates. Sex differences in choosiness are not easily explained, however. The lower-caring sex (often males) has both higher costs of choice, because it is more difficult to find replacement mates, and higher direct benefits, because the sex providing more care (usually females) is likely to exhibit more variation in the quality of contributions to the young. Because both the costs and direct benefits of mate choice increase with increasing parental care by the opposite sex, general predictions about sex difference in choosiness are difficult. Furthermore, the level of choosiness of one sex will be influenced by the choosiness of the other. Here, we present an ESS model of mutual mate choice, which explicitly incorporates differences between males and females in life history traits that determine the costs and benefits of choice, and we illustrate our results with data from species with contrasting forms of parental care. The model demonstrates that sex differences in costs of choice are likely to have a much stronger effect on choosiness than are differences in quality variation, so that the less competitive sex will commonly be more choosy. However, when levels of male and female care are similar, differences in quality variation may lead to higher levels of both choice and competition in the same sex.
