Effects of Undercorrected Astigmatism on Vision

A recent study conducted by Wolffsohn et al from Aston University United Kingdom (J Cataract Refract Surg 2011), revealed that even small amounts of uncorrected astigmatism in post-cataract-surgery patients can have a significant effect on vision quality and if left untreated, can affect the quality of life of older patients.  Uncorrected astigmatism may also contribute substantially to falls among the elderly, the study noted. 

Approximately 85% of the general population has corneal astigmatism and 20%-30% of those >60 years of age have significant astigmatism.  Because cataracts and astigmatism with intraocular lenses (IOLs) offers a viable solution to both cataracts and astigmatism, but many patients do not choose IOLs to correct astigmatism due to added cost. 

"Many public health services consider intraocular lenses that correct astigmatism to be premium," the authors noted.  "Therefore, older patients with coexisting cataract and astigmatism must pay for the IOL as well as the cost of private surgery if they wish to achieve optimum vision."

The study assessed whether leaving patients with uncorrected astigmatism after cataract surgery had an impact on visual acuity and reading speed also decreased with increasing uncorrected astigmatism power.  Light scatter was not significantly affected by uncorrected astigmatism; however, the reliability and variability of measurements decreased with increasing uncorrected astigmatic power.  Driving simulator performance was unaffected by uncorrected astigmatism, although clarity decreased with increasing uncorrected astigmatic power. 

"With modern IOLs implanted after cataract surgery, astigmatism can easily be corrected and the additional cost of these 'premium' IOLs is likely to be far less than the consequences of leaving the patient with uncorrected astigmatism," the authors noted.  "Hence, correction of corneal astigmatism during cataract surgery and IOL implantation should be considered the standard of care."