A 3-dimensional evaluation of the macular region: comparing digitized and film-based media with a clinical evaluation

To compare the results of stereoscopic macular evaluations using three different types of stereoscopic photographic equipment with those of a clinical examination when establishing the presence of possible macular oedema.

The study involved a clinical evaluation of the macular region in 57 eyes of 30 diabetes subjects with possible macular oedema. Clinical examinations were followed by photographic stereoscopic evaluations of the macular region using two digital systems (low and high resolution) and one film-based system. All the photographic recordings were classified by two consultants, who were trained in making macular gradations and blinded to the results of previous assessments.

The low-resolution digital equipment was found to have relatively low optical resolution and found a significantly lower number of eyes with macular oedema compared with the clinical examination. The high-resolution digital equipment and the film-based equipment were found to have relatively high optical resolution. The number of eyes with macular oedema found by the high-resolution digital and film-based evaluations was comparable with the number found by the clinical examination. Low intra- and interobserver agreement was observed.

All three photographic systems have disadvantages that make them suboptimal as tools for evaluating the presence of macular oedema. The film-based system seems the most reliable, while low-resolution digital equipment seems least useful. The development of new and objective measurements giving a 3-dimensional presentation of the macular region might be advantageous.