Cataracts
Monitor older patients for visual acuity

BY Marino J. Discepola, MD

Risk factors

• age -- everyone gets cataracts, you just have to live long enough
• prolonged exposure to ultraviolet B light, so sunglasses are important even in childhood
• smoking -- increases nuclear sclerotic cataracts
• heavy alcohol intake
• steroid use -- both systemic and topical -- greatly raises the risk of posterior subcapsular cataracts
• ocular trauma
• metabolic -- diabetes augments the likelihood of cortical cataracts

Signs and symptoms

• gradually decreasing visual acuity
• progressive clouding or fogging of vision
• monocular diplopia (seeing double)
• increasing myopia, frequent change in eyeglasses
• second sight -- older patients no longer need their reading glasses -- myopia from nuclear cataracts compensates for their farsightedness
• difficulty distinguishing dark colours, e.g. dark blue from black
• problems with driving in bright sunlight
• "white" pupil indicating hypermature cataract
• haloes around lights, similar to those seen with angle-closure glaucoma
• as the cataract increases in size, it predisposes susceptible individuals to angle-closure glaucoma

Screening and referral

• visual acuity chart - a necessity in every family physician's office
• visual acuity </= 20/50
  • patient no longer has the legal ability to drive
  • immediate referral needed
• complaints by patient that his vision is "not what it used to be" -- refer
• elderly individual states that he "sees well"
  • assess visual acuity regularly anyway -- results may be very surprising
  • it's often only after the first cataract is removed that patients realize how poor their vision was
• immature cataract -- still some clear areas in lens, i.e. not totally opacified yet
• cataract should be mature, or "ripe," before proceeding to surgery, i.e. visually significant
• if the wait is prolonged, cataract becomes "over-ripe"
  • more energy required to remove the cataract
  • potentially more damage to the eye
  • higher complication rate

Cataract surgery

• the most commonly performed surgical procedure worldwide
• the most successful -- 99% of patients have their vision improved
• phacoemulsification -- the cataractous lens is removed via ultrasound
• artificial intraocular lens (IOL) is implanted to replace it
• not done by laser
• topical or retrobulbar anesthesia
• out-patient procedure
• wound is self-sealing, usually no sutures are required
• IOL
  • either soft or rigid
  • soft is preferable -- smaller incision and less possibility of a secondary cataract developing
• prognosis
  • if cornea and retina are normal, visual acuity will be 20/20
  • patient can see clearly either far or near without glasses, but not both
  • will need bifocal eyeglasses for best clarity at all distances
  • glasses are prescribed 1 month post-op
• minimum wait for second eye -- usually 2 weeks -- some surgeons do both eyes simultaneousl