Clear lens extraction in high axial myopia

Abstract

Several ophthalmologists, during these past 20 years, supported by the great improvement in the surgical techniques of cataract extraction, proposed again the surgical procedure of clear lens extraction (CLE) to correct high axial myopia. However, we have to remember that vitreous and retinal changes in high myopic eyes can lead to retinal detachment (RD), in some cases with a poor visual outcome even after successful surgery. Moreover, it is well known that cataract extraction is a major cause of later RD with a further significant increase of the incidence of RD after Nd:YAG laser capsulotomy. The increased risk rates of RD for high myopia and cataract extraction are probably to be additive; therefore, high myopic eyes are significantly more exposed to postoperative complications. The greater incidence of RD in these eyes can be explained considering the anomalous vitreous changes occurring in high myopia, precipitated by the molecular and structural changes of the vitreous following cataract surgery. There are anomalous vitreo-retinal separation that are most frequently observed in very high myopic eyes: anomalous posterior vitreous detachment (PVD) and posterior vitreous schisis (PVS), the latter generally observed in association with a prominent posterior stafiloma. Intraoperative observations and recent studies of the macular area by means of optical coherence tomography (OCT) allowed the detection in these eyes of a thin layer of epiretinal tissue strictly adherent to the retina involved by the staphyloma; in these cases tractional retinal detachment, macular schisis or holes can occur. There are only few reports on the vitreo-retinal complications of CLE; for this reason, most conclusions have been derived from studies on RD occurred after cataract extraction in high myopic eyes. These data suggest that the risk/benefit ratio for this operation is probably too high to be recommended.