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Describe the treatment of Cataract

Introduction –
• A cataract is a progressive clouding of the lens in the eye that interferes with vision
and the examiner’s view of the fundus.
• Most cataracts are related to aging. They can occur in one or both eyes. Younger age
of onset can be due to trauma, radiation, diabetes or steroid use.
• Cataract types are defined by their specific location of opacity or clouding within the
anatomical lens and include: nuclear, cortical, subcapsular (anterior and posterior), and
mixed. The nuclear type is more common in the older population whereas the posterior
subcapsular (PSC) type can manifest at any age. The management of cataracts is
similar irrespective of the type.
Risk factors-
• The most common risk factors for cataracts include: diabetes, long term use of topical,
systemic, intravitreal, inhaled or oral corticosteroids and prior intraocular surgery.

Ocular conditions –
• Myopia
• Prior pars plana vitrectomy
• Ocular inflammation
• Chronic ocular disease
• Ocular/orbit trauma
Non-ocular conditions-
• Age
• UV-B light exposure
• Ionizing radiation
• Chronic Steroid use including topical, systemic, intravitreal, inhaled
• Smoking/Tobacco use
• Diabetes2
• Family history
• Hypertension
• Hyperbaric oxygen
• Social determinants of health.
Prevention –
• There is an epidemiologic link between cataract development and smoking, steroid
use, diabetes, and ultraviolet ray exposure. Patients who are subthreshold for surgery
may benefit from lifestyle modification:
→ Smoking cessation
→ Reduced UV-B exposure (e.g. hats, sunglasses with UV-B protection)
→ Safety eyeglasses during high-risk activities at work or recreation to avoid eye
trauma
• Patients who are long-term users of corticosteroids (by any route, dose and duration
dependent) should be informed of the increased risk of cataract formation.
• Nutritional supplementation has not been shown to reduce the rate of cataract
development.

Diagnostic Process –
• There is insufficient evidence to recommend routine screening for impaired vision in
asymptomatic adults.
• In the primary care setting, recognition of risk factors and the use of screening
questions to assess symptoms of visual function (e.g. blur, glare, colour change,
dimming, monocular diplopia), Snellen visual acuity measurement and examination with
an ophthalmoscope can suggest the diagnosis of cataracts. Symptoms and the patient’s
perspective of visual function are important, even with good Snellen visual acuity.
• It is helpful for the primary care practitioner to have a high index of suspicion for visual
causes of functional decline (e.g. falling, mood change, depression, withdrawing from
social activities, cessation of night driving). Consider enquiring whether older patients
have had a recent eye examination. Patients may adapt to their visual impairment and
may fail to notice functional decline that accompanies the progression of a typical
cataract.
• Primary care providers may consider enquiring whether older patients have had a
recent eye examination assessment by an eye care professional (optometrist or
ophthalmologist) is indicated to confirm the diagnosis of cataract and rule out other
causes of vision loss. Slit lamp examination is the gold standard for this purpose, but
does not solely determine who may benefit from cataract surgery as this is a complex,
multifactorial decision.
• As with many other conditions, social determinants of health are important and may
lead to a late cataract diagnosis resulting in more complicated surgery and
postoperative care.
Non-Surgical Management –
During early cataract development, visual improvement may be achieved through a
number of means including:
• changes in spectacle lens prescription
• use of strong bifocals
• magnification or other visual aids
• appropriate illumination
Pupillary dilatation has a limited role in the management of posterior subscapular
cataracts.
Surgical Management –

The presence of a cataract does not itself indicate a need for surgery. Cataract surgery
may be indicated when the cataract reduces visual function to a level that interferes with
everyday activities of the patient and the patient desires surgical intervention to improve
vision.
Glare testing and potential acuity testing can be useful in certain cases in the decision
to recommend or not recommend cataract surgery. The following specific indications for
cataract surgery are suggested:
a) Visual disability and Snellen Acuity of 20/50 or worse
The visual impairment produced by the cataract is responsible for the patient’s
disability in carrying out needed or desired activities (driving, reading, occupational
needs) and the best correctable visual acuity in the affected eye is 20/50 or worse.
b) Visual disability and Snellen Acuity of 20/40 or better
The visual impairment produced by the cataract is responsible for the patient’s
disability in carrying out needed or desired activities (driving, reading, occupational
needs), as documented by any of the following reasons:
• visual disability increases due to glare or dim illumination
• patient complains of monocular diplopia or polyopia
• visual disparity exists between the two eyes
and the best correctable visual acuity in the affected eye is 20/40 or better.
c) Other indications for cataract removal
• Lens-induced disease: phacomorphic glaucoma, phacolytic glaucoma, and other
lens-induced disease may require cataract surgery and the need for extraction may
be urgent.
• Concomitant ocular disease that requires clear media: cataract extraction may be
required to adequately diagnose other ocular conditions such as diabetic
retinopathy.
d) Visual ability in patients legally blind in one eye
The indications for surgery in patients with cataract in one eye who are legally
blind in the other eye are the same as for other patients, except that the risk
of total blindness must be considered and emphasized.

Contraindications for Surgery –
Surgery should not be performed solely to improve vision if:

a) the patient does not desire surgery
b) glasses or other visual aids provide functional vision satisfactory to the patient
c) the patient’s quality of life is not compromised
d) the patient is medically unfit
e) the patient has concomitant disease where functional improvement is unlikely.

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