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Rigid contact lens fitting relationships in keratoconus. Collaborative Longitudinal Evaluation of Keratoconus (CLEK)
T B Edrington1, L B Szczotka, J T Barr
1Southern California College of Optometry, Fullerton, USA.
Summary
Most keratoconus patients wear flat-fitting rigid contact lenses, potentially increasing corneal scarring risk. This study analyzed lens fitting in the CLEK Study, finding most lenses were fitted flatter than recommended.
Area of Science:
- Ophthalmology
- Corneal Diseases
- Contact Lens Technology
Background:
- Keratoconus management often involves rigid contact lenses.
- The apical fitting relationship of these lenses is crucial for corneal health.
- Current standards for rigid lens fitting in keratoconus are not well-documented.
Purpose of the Study:
- To document the standard of care for apical fitting relationships in rigid contact lenses for keratoconus.
- To investigate the prevalence of flat-fitting lenses in keratoconus patients.
Main Methods:
- Analysis of habitual rigid contact lenses worn by 808 patients in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study.
- Comparison of lens fluorescein patterns and base curves to the first definite apical clearance lens (FDACL).
- Random selection of one eye for analysis in patients wearing lenses in both eyes.
Main Results:
- Only 12% of rigid contact lens-wearing eyes exhibited apical clearance; 88% had apical touch.
- Lenses were fitted progressively flatter with increasing keratoconus severity: mild (1.18 D flat), moderate (2.38 D flat), and severe (4.01 D flat).
- On average, rigid lenses were fitted 2.86 D flatter than the FDACL.
Conclusions:
- The majority of keratoconus patients in the CLEK Study were fitted with flat-fitting rigid contact lenses.
- This widespread practice carries a potential risk of corneal scarring.
- Further research is needed to establish optimal fitting guidelines to mitigate risks.