Final answer:
ICD 9 irregular astigmatism refers to a vision defect characterized by an uneven or asymmetrical focus of the eye. It can be partially corrected with corrective eyeglasses or contact lenses.
Step-by-step explanation:
ICD 9 irregular astigmatism refers to the classification and coding system used in the medical field to identify and categorize medical conditions and diseases. Irregular astigmatism is a vision defect characterized by an uneven or asymmetrical focus of the eye, resulting in blurred or distorted vision. It is mostly caused by irregularities in the shape of the cornea but can also be due to lens irregularities or unevenness in the retina.
The eye-brain system can compensate for some of these irregularities, but they generally manifest themselves as less distinct vision or sharper images along certain axes. Astigmatism can be partially corrected with corrective eyeglasses or contact lenses. A cylindrical correction is used to correct astigmatism, while spherical corrections are used for short- or farsightedness.