PCO is still one of the most common complications following modern cataract surgery with IOL implantation. According to the literature the frequency of posterior capsule opacification (PCO) with posterior chamber intraocular lens (IOL) implantation varies widely from less then 10 to more than 50%. The lack of a common definition of clinical PCO is one of the underlying reasons (see also literature overview II). We present EPCO, an easy-to-use software tool, that is independent from visual acuity testing and Nd:YAG laser rates and is based exclusively on morphological assessment of PCO.
Following dilatation of the pupil, standardised retroillumination photographs of the pseudophakic anterior segments should be obtained. We utilised a Zeiss® photoslitlamp model 40 SL/P. PCO is then scored by evaluating these digitised retroillumination photographs. Density areas are simply identified and marked on the computer screen by the observer interactively. The individual PCO-score for each eye is calculated by EPCO multiplying the density of the opacification (graded from 0 to 4) by the fractional PCO area involved behind the IOL optic. EPCO calculates the density surface mathematically by performing pixel counts. Can such a system which is observer dependent really be reliable?