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Did you know that close to one-fourth of astigmats require a correction greater than 2.50D?
A recent study showed an estimated 36% of highly myopic patients (i.e. individuals with greater than -5.00D sphere) have an astigmatism greater than 1.00DC. In addition, 78% of astigmats required cylinder correction between 1.00DC and 2.50DC.1 The implication here is that close to a quarter of the remaining individuals required levels of astigmatism correction greater than 2.50DC.
Correcting for Severe Astigmatism
Example of Severe Astigmatism
The most basic form of correction for astigmatic refractive errors is in spectacles, and it has its benefits. However, given today’s multi-tasking and active lifestyles, toric contact lenses are a much more convenient option for many patients.
Luckily, with the significant enhancements in soft toric designs that have occurred over the past 20 years,2 these severe astigmats are more likely to be satisfied with contact lens correction. Newer specialty toric contact lenses now have the capability to correct for increased amounts of astigmatism, and with better stabilization.
As you may know, practitioners with patients whose cylinder correction requirements are greater can often find themselves in a challenging position. Not only can it be time consuming to find a lens with higher cylinder values, but as astigmatism values increase, the axis will play a more crucial role in the correction. Accuracy in refractions and careful observation of lens movement and rotation is essential in the successful fitting of toric lenses.
Choose a lens that CIBA Vision Specialty Lens Group offers for severe astigmatism:
CIBASOFT® Progressive Toric; Durasoft® 2 OptiFit® Toric; Durasoft® 3 OptiFit® Toric; Durasoft® 3 OptiFit® Toric UV
Toric Multifocal
The high demand for multifocal toric soft contact lenses is continuing to rise with the growing population of astigmatic presbyopes.
An estimated 50,000 new people become presbyopic everyday.3 Incipient presbyopes accustomed to wearing contact lenses for distance correction only may soon find themselves in need for additional correction at near distances.
Multifocal corrective options
For the spherical refractive error patient, this additional correction may be simple, as there are a variety of corrective options. These options include standard monovision and the newer bifocal or multifocal contact lens designs.
With monovision, the dominant eye is best corrected for distance and the fellow eye is corrected for near work. This method works quite well with many people.4 The drawback with monovision is that there is a loss of stereopsis, or depth-perception, since neither eye is clear at all distances.
The benefit of bifocal and multifocal contacts is that there is less of an effect on depth perception. While many patients adapt well to this refractive modality, distance and near vision in both eyes may not be as crisp and sharp as they desire. Communication is vital in fitting patients with presbyopia. It cannot be stressed enough that patients with presbyopia have to accept compromise on the quality of their vision and that most will never see as well as when they were 30 years old.5
Options for astigmatic presbyopes
As astigmatism increases with age, the axis tends to shift more towards an against-the-rule (Axis 090) orientation.6 Until recently, monovision was the only corrective option for presbyopic patients with significant astigmatic corrective needs. Eventually, a full 2.50D difference between the two eyes can lead to a substantial decrease in stereopsis, and some people are unable to adapt to this loss in binocularity.7 Luckily, soft multifocal toric lenses are now available, including the CIBASOFT® Progressive Toric. Its unique single center-near progressive add zone and aspheric back surface provide excellent intermediate and near vision without compromising distance acuity.
- CIBASOFT Progressive Toric was designed to make fitting the astigmatic presbyope clear and straightforward.
- The innovative CIBASOFT Progressive Toric design is acheived by incorporating a center-near Progressive add zone onto the back surface of a proven thin-zone soft toric contact lens.
To learn more about the CIBASOFT Progressive Toric, click here.
Colored Toric
Astigmatic patients wanting to wear colored contacts now have options combining both aesthetic and optical needs.
Colored contact lenses are used for many reasons, including cosmetic and vision enhancement.8-10 In the mainstream market, colored lenses are available in a handful of base-curves, but comparatively few toric parameters. Patients with astigmatism wishing to wear colored contacts sometimes have to compromise by wearing spectacles over their lenses to maximize visual clarity.
Practitioners may also have the option of fitting a spherical-equivalent power, meaning that ½ of the cylinder correction is added to the overall sphere. While this may be useful for some, other patients may continue to experience blurred vision.
Luckily, patients have another option — colored lenses with an astigmatic correction component built in. View the colored toric lenses that CIBA Vision Specialty Lens Group offers: Durasoft® 2 OptiFit® Toric Colors, Durasoft® 2 OptiFit® Toric Colors for Light Eyes, Durasoft 3 OptiFit® Toric ColorBlends®, Durasoft® 3 OptiFit® Toric Colors, Durasoft® 3 OptiFit® Toric Complements®
References
- Heidary G, Ying GS, Maguire MG, Young TL. The association of astigmatism and spherical refractive error in a high myopia cohort. Optom Vis Sci 2005;82(4):244-7.
- Russell CH, Slonim CB. The correction of astigmatism with soft contact lenses. Ophthalmol Clin North Am 2003;16(3):353-8, vi.
- Rakow PL. Presbyopic correction with contact lenses. Ophthalmol Clin North Am 2003;16(3):365-81.
- Back AP, Holden BA, Hine NA. Correction of presbyopia with contact lenses: comparative success rates with three systems. Optom Vis Sci 1989;66(8):518-25.
- Atwood JD. Presbyopic contact lenses. Curr Opin Ophthalmol 2000;11(4):296-8.
- Asano K, Nomura H, Iwano M, et al. Relationship between astigmatism and aging in middle-aged and elderly Japanese. Jpn J Ophthalmol 2005;49(2):127-33.
- Romano PE. A case of acute loss of binocular vision and stereoscopic depth perception. (The misery of acute monovision, having been binocular for 68 years). Binocul Vis Strabismus Q 2003;18(1):51-5.
- Gaume A, Prager TC, Bergmanson JP, et al. Opaque contact lens color choices among women of different ethnic groups. Eye Contact Lens 2003;29(2):93-5.
- Tanzer DJ, Smith RE. Black iris-diaphragm intraocular lens for aniridia and aphakia. J Cataract Refract Surg 1999;25(11):1548-51.
- Swarbrick HA, Nguyen P, Nguyen T, Pham P. The ChromaGen contact lens system: colour vision test results and subjective responses. Ophthalmic Physiol Opt 2001;21(3):182-96
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