Congenital ectopia lentis : diagnosis and treatment

Abstract

Congenital ectopia lentis (EL) is an ocular condition, which typically causes a high grade of refractive errors, mainly myopia and astigmatism. These might be difficult to compensate for, especially in children, who might develop ametropic amblyopia. Surgery on ectopic lenses has previously been controversial, due to the risk of sight-threatening complications.

In paper I we studied retrospectively visual outcomes and complications in children, who were operated for congenital EL, and who had en scleral-fixated capsular tension ring (CTR) and an intra-ocular lens (IOL) implanted at the primary surgery. Thirty-seven eyes of 22 children were included. Visual acuity (VA) improved in all eyes, and only few had persistent amblyopia at the end of the follow-up. A great majority of the eyes had postoperative visual axis opacification (VAO), which was expected, since the posterior capsule was left intact at the primary surgery. Two eyes required secondary suturing for IOL decentration. No eye had any serious complications such as retinal detachment, glaucoma or endophthalmitis.

Congenital ectopia lentis is often an indicator of a systemic connective tissue disorder, and Marfan syndrome (MFS) is diagnosed in 70% of the cases. This genetic disorder affects basically all organ systems in the body, EL and dilatation of the ascending aorta being the cardinal signs. MFS is associated with markedly decreased life expectancy due to the cardiovascular complications. Therefore, an early and accurate diagnosis is of importance.

In paper II we measured the accommodative power, lens thickness, anterior chamber depth (ACD), and pupil size in these eyes, using an optical coherence tomography (OCT). Thirty-one eyes of 31 cases of MFS were included, and these were compared to non-affected controls. We found that the lens was significantly thicker in MFS at all stages. The pupil size was significantly smaller in MFS at baseline, decreased less in accommodation and dilated more during dilatation. No significant difference was seen in the accommodative power or ACD. No difference was seen in any parameter between the MFS eyes with, and without EL. We conclude, that even though the lens and the pupil seem to be affected in MFS, these eyes seem to have the same ability to accommodate as normal subjects. The observed changes seem to be associated to MFS independently of EL.

In paper III we studied the corneal curvature, thickness and endothelial cell density (ECD) in 39 MFS eyes and compared those to non-affected controls. We found significantly lower keratometric (K) values and corneal thickness in MFS, but no difference in the ECD. No significant difference was found in these parameters between MFS eyes with and without EL. We also reported on generally increased corneal astigmatism in MFS, especially in eyes with EL.

In paper IV we described the ocular characteristics in 102 eyes of 56 cases of MFS. We found increased axial length, but mostly only moderate myopia, which seemed to be compensated by the flat cornea. The majority of the eyes had EL, or were pseudophakic due to EL. Other associated diagnosis included amblyopia, glaucoma, retinal detachment and strabismus.

In conclusion, we found that surgery for EL in children, including CTR and IOL gives good visual development and no serious complications. Also, most of the ocular changes in MFS seem to be connected to MFS itself, rather than EL.