Abstract
Abstract: :
Purpose: To investigate the effect of a furosemide, a high ceiling diuretic that inhibits electrolyte reabsorption by inhibiting the NaK2Cl cotransport system, on defocus induced refractive error induction in chicks. Methods: 43 chicks were fitted with +10D, –10D lenses or wore no lens on the right eye, from day 3 to day 10 after hatching. The right eye was injected with 5µl of 5 mM furosemide dissolved in DMSO. Fellow eyes received the same volume of DMSO. Chicks were reared on a 12 hr light 12 hr dark cycle and had unlimited food and water and were maintained at 31degC. Biometry including retinoscopy and A–scan ultrasonography were performed on day 10. Results: Furosemide allowed for complete compensation to +10D lenses, but compensation to –10D lenses was only 5D of myopia, considerably less than the DMSO controls which showed a mean refractive error of over 8D of myopia. There was no significant difference in refractive state between furosemide and DMSO controls for the eye without lenses. Vitreous chamber lengths showed corresponding effects to the refractions. A moderately strong effect of furosemide was observed in the anterior chamber where anterior chamber depth was more than 0.1 mm shorter for the diuretic treated chicks. Conclusions: A defocus sign dependant effect of furosemide was observed with the induction of myopia considerable curtailed despite the strong tendency for chicks reared with only the vehicle solutions to compensate strongly. Thus rather than the diuretic forcing an overall reduction of fluid in the eye, such changes were only observed in combination with negative defocus a condition associated with retention of water in the eye.
Keywords: myopia • emmetropization