Contact Lens Indications and Contraindications

Flashcards covering the indications and contraindications of contact lens and soft contact lens wear, based on lecture notes.

What refractive errors are generally indicated for contact lens wear?

Refractive errors less than -0.75 or greater than +1.50 diopters, depending on visual acuity and symptoms.

Why are keratometry readings important in determining contact lens suitability?

Keratometry readings outside the range of 41.00D to 46.00D may indicate the need for customized lenses or suggest keratoconus.

What is the acceptable tear breakup time (TBUT) for contact lens wear?

A tear breakup time (TBUT) of 10 seconds or more is generally desirable for contact lens wear.

What corneal conditions are important to consider for contact lens wear?

Sequential staining, scarring, or distortion of mires on the cornea are contraindications, while regular astigmatism up to -3.50 DC may be corrected with contact lenses.

Besides corneal and refractive considerations, what other physical or practical factors are important for contact lens wear?

Good lid position (not showing sclera at the top or bottom), adequate manual dexterity, and the ability to handle lenses properly.

What are some special indications for contact lens wear?

Keratoconus (specialty lenses like Rose-K), irregular astigmatism (RGP lenses), post-LASIK/refractive surgery (SCL or RGP), post-corneal transplants (specialized RGP), and therapeutic bandage or medicated CLs.

What occupations or situations are general contraindications for contact lens wear?

Welders, miners, construction workers, plumbers, carpenters, and car mechanics due to at-risk occupations; poor personal hygiene; poorly motivated patients; and those going on a trip shortly (new wearers).

What patient health factors are general contraindications for contact lens wear?

Chronically anxious individuals, heavy smokers, those with acute/subacute inflammations of the anterior segment, acute/chronic ocular infections, and strabismus/ptosis.

What allergic and dry eye conditions are contraindications for contact lens wear?

Allergies (giant papillary conjunctivitis, hay fever, drug reactions, atopic skin reactions), and dry eyes (aqueous/lipid/mucin deficiencies, extreme xerosis) are contraindications for contact lens wear.

What skin or handling issues are general contraindications for contact lens wear?

Skin disease (infection, chronic blepharitis, swollen lid margins), handling problems (dirty fingernails, poor hygiene, arthritis/Parkinson's tremor/psoriasis).

What systemic medications can pose potential contraindications for contact lens wear?

Medications for gastric ulcers, isotretinoin, acne medication, birth control pills, sleeping pills, and tranquilizers may cause reduced tear flow or fitting difficulties.

What systemic diseases are general contraindications for contact lens wear?

Unstable diabetes (unstable refraction), thyroid disease with exophthalmos (lens dislodgement, dry spots).

What properties make soft contact lenses more comfortable than RGP lenses?

Low tensile modulus, high degree of elasticity, and total diameter extending beyond limbus.

For what types of patients are SCLs ideally indicated due to comfort?

Patients with sensitive eyes or those who previously failed with spherical rigid lenses due to discomfort.

What are the general indications for SCL wear?

Rapid adaptation, occasional wear, low refractive errors, uniocular wear, sports, occupational needs, flare with rigid lenses, persistent ‘3 and 9’ o’clock staining, paediatric wear, therapeutic wear, and cosmetic lenses.

What material properties of SCLs make them a contraindication for wear?

Variable vision due to blinking, tear film changes, or environmental hydration effects; breakage and tearing.

What maintenance considerations make SCLs a contraindication for wear?

It is not feasible to modify the power or fitting parameters; verification is difficult; chemical contamination is possible due to porous structure.

What patient populations with unique visual needs are contraindicated for SCLs?

Patients with one eye blind/low vision, aphakia, or anisometropia require proper education on ocular emergencies.