Irregular Astigmatism

Irregular change of refractive power in different meridia

Etiological Types

• Curvatural IA

– Extensive corneal scars

– Keratoconus

• Index IA

– Cataract

Clinical Picture

• Signs

– Defective vision

– Distortion of objects

– Polyopia

• Symptoms

– Retinoscopy: Irregular pupillary reflex

– Slitlamp exam: Corneal irregularity

– Placido’s disc test: Distorted circles

– Photokeratoscopy: Irregular corneal curvature

Treatment

• Optical treatment

– Contact lens

• Phototherapeutic keratectomy

– Excimer laser

– Superficial corneal scar

• Surgical treatment

– Extensive corneal scarring

– Penetrating keratoplasty

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