• Toric IOLs are used to correct corneal astigmatism

• This design is highly useful as a way of reducing pre-existing astigmatism in patients undergoing cataract surgery

• The toric correction can be incorporated into the anterior, posterior or separated into both of the surfaces

 

 

To ensure a successful correction:

- Surgeons must be able to carry out a surgical procedure which is astigmatically neutral

- The axis of the toric IOL must be correctly aligned during surgery

- The axis must not rotate out of alignment post-operatively 

 

 

• Bellucci et al (2013) found that the final refractive error is dependent on the accuracy of alignment of the IOL.

  • Each degree of misalignment produces a 3% reduction of the effect

  • When the misalignment is above 30%, a post-operative astigmatic effect is produced which is greater than the initial corneal astigmatism

    • Therefore, it is vital for the lens to stay aligned intraocularly

 

 

                                                                   Toric IOL examples: 

STAAR surgical IOL                                   Acrysof IQ Toric (Alcon)

 

 

 

 

 

 

 

 

 

 

• In a comparison study between both lenses:

  • Corneal astigmatism was effectively reduced

  • Good rotational stability

  • The main problem is the initial alignment

    • No reported cases of late rotation with any toric designs.

    • Despite problems of ‘haloes’ in some patients, toric IOLs have proved to be effective in managing astigmatism