3.00 D या अधिक का नियमित दृष्टिवैषम्य: जब चश्मा 20/25 दृष्टि तीक्ष्णता प्राप्त नहीं करता

References

1. High refractive errors are defined as 6.00 D or more of myopia, 3.00 D or more of hyperopia, and 3.00 D or more of regular astigmatism.
2. High astigmatic errors can be corrected effectively with rigid gas-permeable and hybrid contact lenses.
3. In cases of greater amounts of corneal astigmatism, it may be preferable to use a bitoric or back-surface toric contact lens–design in order to minimize corneal bearing and improve centration.
4. Custom-designed soft toric contact lenses provide another means to correct high astigmatic refractive errors.
5. Rigid gas-permeable scleral lenses (diameter more than 17 mm) are an option for the correction of high and/or irregular astigmatism, particularly if combined with anisometropia.