Eye Problems

Common Vision Problems

Refractory vision abnormalities are conditions that affect the focal point of vision relative to the retina. They include myopia, hyperopia and astigmatism.

Myopia, commonly known as nearsightedness, is a condition where the refracting power of the eye is greater than normal. This places the focal point of the eye anterior to the retina.

Hyperopia, commonly known as farsightedness, is a condition where the refracting power of the eye is less than normal. This places the focal point of the eye posterior to the retina.

Astigmatism is a condition where the corneal surface is asymmetric, which causes inconsistent refraction of light into the eye. This results in blurred vision.

Refractory vision abnormalities present with blurred vision. Myopia worsens as the object gets farther away, while hyperopia worsens when the object gets closer.

Refractory vision abnormalities are treated with corrective lenses. Myopia and hyperopia can also be corrected surgically.

Strabismus, also known as heterotropia, is a condition of the eye where an abnormal alignment is not able to be overcome by normal motor control.

Patients with strabismus will demonstrate a gaze for each eye that is in different directions. This results in double vision and progressive blindness. If untreated, the visual information from the misaligned eye can be suppressed, leading to amblyopia, which is discussed below.

Strabismus is treated with vision training, with surgery often required to align the eyes bilaterally.

Amblyopia, also known as lazy eye,is the result of a developmental defect in the neural pathways of the eye.

Patients with amblyopia will have poor visual acuity and spatial differentiation in the affected eye.

Amblyopia is treated with either patching or atropine drops. Patching is usually preferred by parents due the anticholinergic effects of atropine.

Presbyopia is an age-related disorder that is caused by the loss of lens elasticity and concomitant loss of accommodating power.

Patients with presbyopia experience difficulty reading at close range and thus have a classic history of holding reading materials at arm's length.

Pupil

Argyll Robertson pupil is a condition where the patients pupil does not constrict in response to light, but does constrict in order to accommodate to near objects. It accommodates but does not react.

A common association/cause of Argyll Robertson pupil is syphilis, which is why it is also known as “prostitutes pupil.” Other causes includes SLE and DM.

Marcus Gunn pupil is a condition where light shined in the affected pupil produces a markedly smaller consensual light reflex than when shined in the normal pupil. This can be tested with the “swinging flashlight test.” The examiner shines a light into the normal eye, causing both pupils to constrict. The examiner then swings the light to the abnormal eye. Damage to the afferent fibers of cranial nerve II in Marcus Gunn pupil means that less light is perceived, and neither pupil will constrict.

The cause of Marcus Gunn pupil is an afferent nerve defect, commonly the optic nerve.

Horner syndrome is the combination of ptosis, miosis, and anhidrosis.

The cause of Horner syndrome is a sympathetic trunk lesion, a common etiology of which is a pancoast tumor.

Adie Pupil

Adie Pupil is a condition where the patients pupil is tonically dilated and responds slowly to light.

The cause of Adie pupil is damage to the parasympathetic innervation to the iris.

MLF syndrome

MLF (medial longitudinal fasciculus) syndrome is a condition affecting lateral gaze where the abduction of one eye is not paired with adduction of the contralateral eye.

The cause of MLF syndrome is damage to the medial longitudinal fasciculus, which is commonly seen in MS and intracranial lesions.