eye disorders
Cataract
Symptoms and Signs of Cataract
Cataracts usually develop slowly over years. Early symptoms may be loss of contrast, glare (ie, halos and starbursts around lights, not photophobia), needing more light to see well, and problems distinguishing dark blue from black. Painless blurring eventually occurs. The degree of blurring depends on the location and extent of the opacity. Monocular double vision or ghost images occur rarely. With a nuclear cataract, distance vision worsens. Near vision may improve in the early stages because of changes in the refractive index of the lens; presbyopic patients may be temporarily able to read without glasses (second sight). A posterior subcapsular cataract disproportionately affects vision because the opacity is located at the crossing point of incoming light rays. Such cataracts reduce visual acuity more when the pupil constricts (eg, in bright light, during reading). They are also the type most likely to cause loss of contrast as well as glare (halos and starbursts around lights), especially from bright lights or from car headlights while driving at night. Rarely, the cataract swells, pushing the iris over the trabecular drainage meshwork and causing its occlusion and thus secondary closed-angle Overview of Glaucoma and pain. 