Minimum amount of astigmatism that should be corrected

Abstract

In most subjects, astigmatism less than 0.5 D did not degrade visual acuity. This suggests that under clinical conditions, the visual benefit of precise correction of astigmatism less than 0.5 D would be limited.

Influence of intraocular astigmatism on the correction of myopic astigmatism by femtosecond laser small-incision lenticule extraction

“…Furthermore, it has been found that the postoperative manifest astigmatism after LASIK is mostly against the rule, 14 which might affect visual acuity more adversely than the preoperative astigmatism, whose axis is mostly with the rule. Because a low TIA (%0.5 degrees) has minimal influence on visual acuity, [15][16][17][18] it could be left uncorrected or undercorrected. Moreover, the existence of ORA should be carefully considered before attempting correction in cases with a low TIA.…”

Surgical management of astigmatism with toric intraocular lenses

“…The correction of less than 0.50 D of corneal astigmatism does not seem to improve visual performance (56) . However, in patients with corneal astigmatism above 0.75 D, implantation of toric IOLs is associated with better visual outcomes than monofocal IOLs: significantly more patients achieve an UDVA better than 20/40 and better than 20/25, are spectacle-independent, and have a lower absolute residual refractive cylinder (3) .…”

Effect of corneal biomechanical properties on surgically-induced astigmatism and higher-order aberrations after cataract surgery

“…For patients with cataracts in both eyes, the eye with the lowest sharpness of vision was included in the study. Exclusion criteria included a history of ocular surgery or ocular surface disease and astigmatism of the frontal corneal surface exceeding 0.50 D (6,7) . Patients with diabetes were also excluded from the study because the blood glucose concentrations associated with this disease can alter corneal biomechanical properties (8) .…”