[Posterior capsular opacification: one factor to be considered for the study of the optic nerve].

EDITORIAL It is known that pseudophakia is a very frequent condition in ophthalmology. The visual benefit obtained after a cataracts operation can diminish in time due to the progressive development of a posterior capsule opacification (PCO). Even though surgical techniques and the design and materials of intra-ocular lenses have been continuously modified, PCO continues to be the most frequent long-term post-surgical complication in cataracts surgery (1). The PCO rates vary from one study to another, but a meta-analysis published in 1998 reported that 25% of patients submitted to cataracts surgery developed PCO 5 years after the operation (2). PCO is secondary to the proliferation and cen-tripetal migration of epithelial lens cells from the equator and the anterior capsular sac which end up obstructing the visual axis. According to the growth patterns of these cells, the ensuing opacity assumes a fibrous or pearly appearance and, more frequently , a combination of both (3). Said changes in the posterior capsule may involve visual acuity loss, alteration of contrast sensitivity , glare and monocular diplopia (4,5). Meta-plasia of epithelial cells also causes indirect complications related to mechanical traction. Thus, epithe-lial cells can become fibroblasts containing contrac-tile elements (miofibroblasts) which produce wrinkles on the posterior capsule. These wrinkles or folds also cause visual distortions such as glare or similar to those caused by a Maddox rod (6). All the above irregular combined formation of fibrosis, pearls and wrinkles of the posterior capsule alter reflection, refraction, diffraction and dispersion of light in the eye and may interfere not only with the patient's eyesight but also with the tests carried out for assessing the optic nerve. In our daily practice it is not unusual to assess pseudo-phakic eyes with PCO which may have concomitant optic nerve pathologies such as glau-coma or a neuro-ophthalmic disease. In the light of specific clinical situations we pondered how PCO could influence the results of the tests made for evidencing the functional and morphological condition of the optic nerve and the peripapillary reti-nal nervous fiber layer (PRNFL). To this end we designed a number of studies, comparing results of different diagnostic tests (automated perimetry, laser polarimetry and Optical Coherence Tomog-raphy) before and after a capsulotomy in PCO patients. In what concerns automated perimetry (AP) we observed that not only the mean deviation (indicating the degree of global field depression) but also the standard deviation from the mean value (indicating the degree …