Purchase this article with an account.
K. Kawai, T. Suzuki, K. Hayakawa, H. Oohashi; Accelerated Deterioration Test of a Foldable Acrylic Intraocular Lens by an Experimental Technique, and the Significance of This Test. Invest. Ophthalmol. Vis. Sci. 2010;51(13):4569.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
For faster prediction of deterioration of intraocular lenses (IOL), we performed an accelerated deterioration test by using the Arrhenius equation, which is an empirical equation that expresses the principle that "the lower the temperature, the slower a given chemical reaction will proceed, and, conversely, the higher the temperature, the faster a reaction will proceed." According to the Arrhenius equation, the recommended heating temperature was 50-60ºC, and we calculated the period of the 5-year accelerated deterioration test to be 371 days. We performed a 60°C accelerated-deterioration test on each type of soft acrylic IOL, and we investigated whether we could predict the same changes in these tested lenses as in IOLs that have been inserted into a human eye.We predicted the metamorphosis and deterioration of soft acrylic IOLs and evaluated these changes after 5 years.
We selected 3 pieces each of 11 kinds of acrylic soft lenses (IOL).Clear hydrophobic acrylic: MA60BM, SA60AT, AR40e, VA-60BB, N4-18B, AU6Colored hydrophobic acrylic: SN60AT, YA-60BB, N4-11YB, AN6Clear hydrophilic acrylic: HP60MWe placed each of the IOLs into a 50-ml screw tube bottle containing ultrapure water and let them soak for 371 days in a 60°C oven. After observing the appearance of the IOLs, we measured the changes in their weights, optic diameters, and center thicknesses, and we calculated the rate of these changes before and after the test.
Observed deterioration:IOLs that uniformly changed to a glistening-like appearance:MA60BM, SA60AT, VA-60BB, N4-18B, SN60AT, YA-60BB, N4-11YBIOLs that showed slightly granular glistening: AR40eIOLs that showed glistening only in their centers: AU6, AN6IOLs that did not show any glistening: HP60MRate of weight change: Tended to increase for all of the IOLs. In particular, SA60AT increased 3.5% and AN6 increased 3%.Rate of change of the optic diameter: Increased about 0.4% in AU6 and AN6.Rate of change of center thickness: Decreased about 1.5% in HP60M. Less than ±0.5% in the other IOLs.
Soft acrylic lenses have molecular structures that retain their soft shape. Based on this accelerated test, we concluded that the opacity of these lenses was caused by the entrance of water molecules into these molecular structures. However, IOLs with water content of 0.5% or more tended to have minimal opacity.
This PDF is available to Subscribers Only