It causes irregular astigmatism that can often be corrected by spectacles.

Irregular astigmatism that causes ghost images or double vision.

Irregular astigmatism - principal meridians are not perpendicular.

This is called irregular astigmatism.

You have irregular astigmatism.

(This is regular astigmatism, which is by far more common than irregular astigmatism where separations are other than 90 ).

Soft contact lenses for irregular astigmatism after LASIK.

The cornea just above the region of thinning is of normal thickness, and may protrude anteriorly, which creates an irregular astigmatism.

Although irregular astigmatism is commonly associated with prior ocular surgery and trauma, it is also naturally occurring and prevalent.

Unlike other astigmatism analysis approaches, the Alpins Method can independently analyze the 2 hemimeridians of irregular astigmatism.

Corneal surface marker and marking method for reducing irregular astigmatism during lamellar (LASIK) corneal surgery (1997)

It has only recently become possible to measure the aberrations of the eye and with the advent of refractive surgery it might be possible to correct certain types of irregular astigmatism.

The eye examination may proceed to measurement of the localized curvature of the cornea with a manual keratometer, with detection of irregular astigmatism suggesting a possibility of keratoconus.

Irregular astigmatism is often caused by a corneal scar or scattering in the crystalline lens, and cannot be corrected by standard spectacle lenses, but can be corrected by contact lenses.

The continuation of corneal irregular astigmatism can be quantified in diopters (D) as the topographic disparity (the vectorial difference between the 2 opposite semimeridian values for magnitude and meridian) when displayed using a DAVD.

He ended up with a significant overcorrection of his nearsightedness and vision that is distorted by halos and starbursts in dim light and at night, an irregular astigmatism and floaters in one eye and dryness in both.

Corneal topography or computer-assisted videokeratography (CAVK)-a technique that produces an image map based on the refractive power of the cornea at many discrete points on its surface-shows that irregular astigmatism comes in various configurations.

Another rarely used refraction technique involves the use of a stenopaic slit (a thin slit aperture) where the refraction is determined in specific meridians - this technique is particularly useful in cases where the patient has a high degree of astigmatism or in refracting patients with irregular astigmatism.