Management of astigmatism calls for complex strategies for best results
Among refractive errors, astigmatism poses the greatest challenge to surgeons. Correcting an irregular shape requires complex treatment plans for lasers, precise alignment strategies for IOLs and nomograms for relaxing incisions. Surgeons have to take into account that long-term results might be jeopardized by the natural repair mechanism of the cornea, which leads to "filling in" irregular gaps, inducing regression and having to deal with the potential threat of IOL rotation.
Technological advances have improved the chances of addressing astigmatism with precision and safety. On one hand, corneal topography, wavefront aberrometry and optical coherence tomography allow mapping of astigmatism and the creation of customized treatment plans. On the other hand, the new laser eye trackers with dynamic cyclotorsion compensation allow for precise delivery of laser ablation. IOL technology offers premium toric models with increasingly higher performance. Many methods for accurate sizing and alignment of IOLs have also been developed. In addition, the femtosecond laser promises to revive incisional techniques.
"We have a wide choice of [treatment] options. A first selection is made depending on whether the patient is a cataract or just a refractive surgery patient. And in case of a young refractive surgery patient, any degree of astigmatism is treated. Even a small amount of astigmatism - for example, 0.25 D - is treatable' Jerry Tan, MD, said. "If the patient is a cataract patient, then I will consider toric IOLs if the astigmatism is 0.75 D and above."
Source: Ocular Surgery News APAO Edition July/August 2013 | Healio.com/Ophthalmology