Use of photographic techniques to grade nuclear cataracts

Methods for objectively documenting and grading different varieties of lens opacities are needed in order to conduct research on risk factors for cataracts. This study tested the feasibility and reliability of using two different photographic methods to grade nuclear opacities. Photographs were taken of 41 eyes using a regular Topcon SL-5D photo slit lamp, and using a Topcon SL-45 (Scheimpflug) camera. The photographs were graded against a set of four standard photographs of increasing nuclear opacification. Densitometric analyses were also performed on both sets of photographs. The clinical grade, on examination, of the nucleus was compared to the examiner's grade of each photograph. Agreement was fair between the examination results and the grading of the photographs. Inter-observer reliability was high (kappa = 0.71) with photographs taken using the photo slit lamp. Moreover, the severity grading of the photographs showed a good correlation with the severity of opacity as determined by densitometric analyses. On the basis of these data, and on the field experience, the use of photographs of the nucleus obtained by photo slit lamp may be used in epidemiological surveys.