Cataract Surgery in Small Eyes

Abstract

Eyes smaller than normal (axial length less than 20.5 mm) can be classified into two categories according to anterior chamber depth: those with microphthalmos (short anterior chamber depth) and those with high axial hyperopia (normal anterior chamber depth) [1]. Eyes with short anterior chamber depth and normal axial length are classified as having relative anterior microphthalmos (Fig. 13.1) [2]. Depending on the presence or absence of an accompanying anatomic malformation in the anterior or posterior segment of the eye, eyes with microphthalmos may be subdivided further into those with simple microphthalmos (or nanophthalmos) and complex microphthalmos [3]. In the latter, microphthalmos is accompanied by anatomic malformations, including chorioretinal colobomas, persistent hyperplastic primary vitreous, and retinal dysplasia [3]. Phacoemulsification of these eyes and implantation of intraocular lenses (IOLs) are challenging, with high risks of intraoperative and postoperative complications such as zonular dehiscence, severe uveitis, uveal effusion, cystoid macular edema and aqueous misdirection. Furthermore, the risk of complications increases in proportion to the reduction in axial length [4]. Recent developments in phacoemulsification and devices used for IOL implantation have overcome these challenges, resulting in satisfactory clinical outcomes [4–6].