Document OEGL791GypkmM0KJyVOkM6de

The cornea: the window of the eye The cornea: the window of the eye Regular astigmatism Very common type of refractive error in normal eyes One meridian of the cornea is more curved than the other: as a result the curvature of the cornea looks like a rugby ball rather than a round foot ball This error can be easily corrected with Foot ball (spherical shape) spec(teRaguggcbshlyaebpaeslld)and soft (toric) lenses Figure from https://www.slideshare.net/helleravinas/astigmatism-56625998 Irregular astigmatism Occurs only in eyes with corneal disease (keratoconus, scars,...) The cornea is distorted with areas of steepening and flattening occurring in a chaotic pattern This error cannot be corrected with Corneal map: regular astigmatism and irregular corneal shape spectacles nor with soft contact lenses that mold to the irregular shape Distortion of the cornea in keratoconus Distortion of the cornea in keratoconus Distortion of the cornea in keratoconus Distortion of the cornea in keratoconus Distortion of the cornea in keratoconus Distortion of the cornea in keratoconus Distortion of the cornea in keratoconus The effect of irregular astigmatism on the refraction of light rays The effect of irregular astigmatism on the refraction of light rays The effect of irregular astigmatism on the refraction of light rays The effect of irregular astigmatism on the refraction of light rays The effect of irregular astigmatism on the refraction of light rays The effect of irregular astigmatism on the refraction of light rays The effect of irregular astigmatism on the refraction of light rays Correction of visual acuity in irregular astigmatism with rigid lenses Rigid gas permeable contact lenses do not mould to the irregular surface thereby optically correcting the irregularity and restoring focus on the retina Correction of visual acuity in irregular astigmatism with rigid lenses Rigid gas permeable contact lenses do not mould to the irregular surface thereby optically correcting the irregularity and restoring focus on the retina