Case history
Case history #1
A 25-year-old man complains of eye fatigue and excessive tearing while reading or driving long distances. He also notes that he prefers to bring reading material closer to his face than previously. His uncorrected visual acuity is 20/25 in both eyes at distance as well as at near; ophthalmologic exam is otherwise normal. However, refraction reveals 1 diopter of astigmatism on the vertical meridian in both eyes.
Case history #2
A 16-year-old girl is referred to the ophthalmologist due to an unsatisfactory visual acuity in the predriving license exam. She claims that over the last few years she has experienced blurred vision both at distance and at near, and burning eyes when reading, but has done nothing about it so far. Her uncorrected visual acuity for distance is 20/40 (right eye) and 20/30 (left eye) and for near vision is 20/60 (right) and 20/40 (left). On retinoscopy, large cylinders of 3.50 and 2.00 diopters on the horizontal meridian are found.
Other presentations
There are special forms of astigmatism with different characteristics and clinical presentations. Astigmatism that cannot be corrected accurately using spectacles with ordinary cylinders raises the suspicion of an irregular astigmatism. This type of astigmatism is usually the result of injury or other diseases affecting the cornea. Keratoconus, a common, degenerative, noninflammatory condition affecting the cornea, is often involved. It is characterized by thinning and ectasia of the cornea with resultant poor visual acuity. Typically, the earliest complaint of the keratoconic patient is that they are never satisfied with their spectacle correction. They usually report numerous changes in their prescription over a relatively short period of time and they tend to narrow the palpebral aperture in order to see better. Other symptoms may be halos around lights, photophobia, ghost images, and monocular diplopia.
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