In vivo lens density measurements using the IntraOptics opacity lensmeter.

We evaluated 589 eyes using the IntraOptics opacity lensmeter 701. Twenty-one eyes contained poly(methyl methacrylate) intraocular lenses. The patients in the phakic group (578 eyes), who had no ocular pathology other than refractive error or cataracts, averaged 60.3 years of age, had an average visual acuity of 20/30, and displayed an average lens density as measured with the opacity lensmeter of 22.09. The data were analyzed for the effect of age upon density using various regression models. The best fit was obtained with an exponential model: Density = 6.2 x e(0.02 x Age), with a correlation coefficient of 0.759. The average density for the pseudophakic group (mean age = 68.5) was 9.23. Neither cortical nor posterior subcapsular cataracts were well recorded. Our results indicate that the IntraOptics opacity lensmeter is a rapid and accurate instrument for documenting nuclear cataract changes. The opacity lensmeter may prove useful not only as a clinical tool for monitoring cataract progression but also as an "electronic" second opinion.