A 76-year-old woman reports a gradual decrease in vision OU over the past 14 months. Her past ocular history is unremarkable. On exam, her best-corrected visual acuity is 20/60 OD and 20/50 OS. Fundus exam is normal. Slit lamp appearance of the eyes is shown below:
What type of cataract is this and what is the etiology?
These cataracts have an unusual appearance because of the refractile intralenticular crystals, which are cholesterol deposits. They are referred to as Christmas tree decoration cataracts, and they are not associated with hypercholesterolemia. However, the term Christmas tree cataract is most commonly known to describe the characteristic cataract (polychromatic iridescent crystals) that develops in patients with myotonic dystrophy. Nuclear sclerotic changes also are evident in this patient.
What are the risk factors for acquired cataracts?
Cataracts are most commonly associated with aging, but other risk factors include UV-B radiation, smoking, medications (particularly steroids), and trauma. In addition, intraocular surgery, ocular inflammation, other eye diseases and systemic diseases (i.e., diabetes [cortical or posterior subcapsular cataracts, snowflake cataract], hypocalcemia [small white dots/flakes], myotonic dystrophy [Christmas tree cataract], Wilson’s disease [sunflower cataract], atopic dermatitis [anterior subcapsular cataract], neurofibromatosis type 2 [posterior subcapsular cataract]) can cause cataracts.
What are the characteristic symptoms of common senile cataracts?
Nuclear sclerotic cataract: vision worse at distance than at near (myopic shift), monocular diplopia.
Posterior subcapsular cataract: vision worse at near than at distance, vision worse in bright light, glare/halos.
What are the indications for cataract surgery?
Cataract surgery is recommended when visual symptoms interfere with the ability to perform daily activities and the patient wants better vision. This is subjective and variable depending on the patient and his or her individual needs. Objective criteria (i.e., Snellen visual acuity) are less important because a patient may have significant difficulty with vision despite excellent visual acuity.
Medical indications for cataract surgery include lens-induced glaucoma or uveitis, and when the cataract interferes with examination or treatment of other ocular disorders (i.e., diabetic retinopathy, glaucoma, age-related macular degeneration).