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Contact Lens Evaluation

Contact lens evaluation — a comprehensive examination including selection of the appropriate lens type, corneal measurements and safe-use training.

A planning examination that covers corneal topography, tear film analysis and lens fitting tests for the correction of refractive errors with contact lenses; the appropriate lens type (soft, rigid, orthokeratology) and the rules for cleaning and use are determined.

Indication

  • Wish to use contact lenses instead of glasses for cosmetic and lifestyle reasons
  • Patients who cannot wear glasses due to sports, art or occupational reasons
  • Improvement of visual quality in patients with high myopia, hyperopia or astigmatism
  • Balancing in cases of anisometropia (significant difference between the prescriptions of the two eyes)
  • Keratoconus, corneal irregularity and pellucid marginal degeneration
  • Correction of residual refractive errors after refractive surgery
  • Orthokeratology or soft multifocal lenses for myopia control in children

Preparation

  • Bring current eyeglasses and any previous lens prescription
  • Soft lenses should be removed 24-48 hours and rigid lenses 1 week before the examination
  • History of allergies, ocular drops and systemic diseases should be reported
  • Conditions such as diabetes, rheumatic disease and immunodeficiency should be noted
  • If dry eye, blepharitis or chronic conjunctivitis is present, pre-treatment is planned

How it's performed

  1. A complete eye examination evaluates the health of the cornea, conjunctiva and eyelids
  2. Refraction is measured and visual acuity is determined
  3. A corneal curvature map is generated by corneal topography/keratometry
  4. Tear quality is measured by Schirmer test and tear break-up time (TBUT)
  5. A suitable trial lens is fitted to the patient and lens movement, centration and vision are checked
  6. Training on lens insertion-removal and cleaning rules is provided

Post-procedure

  • A fitting follow-up examination within 1-2 weeks after starting lens use
  • Routine evaluation every 3-6 months in the first year and at least annually thereafter
  • Lens solution expiration date should be observed and the lens case should be replaced every 3 months
  • In case of redness, pain, light sensitivity or blurred vision, the lens should be removed and a physician consulted
  • Adherence to the recommended wearing time (daily/monthly) and the rules for removing lenses during sleep

Risks

  • Bacterial, viral or Acanthamoeba-related corneal infections (especially when lenses are worn during sleep)
  • Corneal epithelial erosion, corneal edema and neovascularization
  • Allergic reaction to the lens solution or lens material
  • Increase in dry eye complaints
  • Sight-threatening complications in cases of misuse and inadequate hygiene

FAQ

Are contact lenses suitable for everyone?

They are suitable for most patients, but may not be appropriate in cases of dry eye, advanced corneal disease, uncontrolled allergy or immunodeficiency. Suitability is determined by examination.

Is it safe to sleep with contact lenses?

It is generally not recommended. Sleeping with lenses reduces corneal oxygenation and significantly increases the risk of infection. Only lenses specifically approved for overnight use may be worn under physician supervision.

How are contact lenses cleaned?

Hands should be washed with soap; the lens should be rubbed with the recommended multi-purpose solution, rinsed, and placed in a clean lens case. Tap water, saliva or normal saline should not be used. The lens case should be cleaned weekly and replaced every 3 months.

What should I do if my eye becomes red?

Remove the lens and consult an eye specialist immediately. Redness, pain, light sensitivity or blurred vision may be signs of a corneal infection; early treatment prevents vision loss.