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Toric and toric-multifocal IOLs and meridional amblyopia

Session Details

Session Title: Toric IOL Outcomes

Session Date/Time: Monday 07/10/2013 | 16:30-18:30

Paper Time: 18:21

Venue: Auditorium (First Floor)

First Author: : K.Muthusamy UK

Co Author(s): :    C. Claoué              

Abstract Details

Purpose:

To Educate Ophthalmologists as to the risk of meridional amblyopia when using toric and toric-multifocal IOLs

Setting:

We have researched the evidence base for the existence of meridional amblyopia and extrapolated the results of laser vision correction (LVC) to lens-based correction of high congenital astigmatism

Methods:

Search on patients with high astigmatism (at least 3 Dioptres) and suboptimal Best Spectacle Corrected Visual Acuity (BCSVA) secondary to meridional amblyopia, and the results of LVC in this population

Results:

The clinical existence of meridional amblyopia has been recognized in both the human and animal models since the 1970s. Meridional visual deprivation during a critical period of development results in reduced response to stimuli in those orientations that persists after the deprivation is eliminated. Children with high astigmatism who have undergone treatment with spectacle correction of the refractive error and patching in childhood may still have an amblyopia that is not fully corrected. The residual meridional amblyopia could be attributed to reduced BCSVA due to the distortion and suboptimal image quality achieved with spectacle correction of high astigmatism. Spectacle correction in patients with high astigmatism is limited by the stability of the spectacle frame and hence a suboptimal retinal image quality is obtained with spectacle correction. Significant post operative visual acuity improvement in patients post LVC would also suggest that some patients labelled as refractive amblyopia in fact have a suboptimal optical correction amenable to either LVC or toric/toric-multifocal IOL implantation. Adults with meridional amblyopia may therefore still achieve an improvement in BCVA following Toric IOL implantation

Conclusions:

Toric IOLs provide a more stable refractive correction, less image distortion and as a result could potentially improve the end BCVA of patients with high astigmatic refractive errors. Ophthalmologists using toric IOLs for the treatment of high congenital astigmatism need to be aware of meridional amblyopia and the limitations this places on outcomes, although a more stable optical correction may also produce a significant improvement in BSCVA

Financial Interest:

NONE