Biomedical subjects

D P Libassi

Publications and source records attributed to D P Libassi.

3 recordsLinked to original sources

PubMed1996

Standardized rigid contact lens fitting protocol for keratoconus.

Keratoconus is typically managed by a variety of rigid contact lens fitting techniques and lens designs. The two most fundamental fitting techniques are apical corneal touch (including divided or three-point touch) and apical clearance. In the course of designing a multi-center study of keratoconus patients, a standardized keratoconus fitting protocol was developed. All contact lens parameter options are uniform except for base curve and secondary curve radii, which are determined by interpretation of fluorescein patterns using the CLEK Study trial lens set and protocol. The initial trial lens's base curve is the average keratometric reading; sequentially steeper lenses are applied until definite apical clearance is observed. We have evaluated the feasibility of this standardized fitting protocol on 30 keratoconus patients. Our results suggest that we have developed a standardized contact lens fitting set and fitting protocol to simplify contact lens management in patients with mild to moderate keratoconus.

Contact Lenses↗

PubMed1996

Feasibility of fitting contact lenses with apical clearance in keratoconus.

Despite the wide variety of rigid contact lens fitting philosophies for the visual correction of keratoconus, questions remain, including which approach-flat, divided support, or steep-contributes the most toward the preservation of a clear cornea. One goal of the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Pilot Study was to determine the feasibility of managing early keratoconus patients with apical clearance rigid contact lenses. Of 30 keratoconus patients identified with at least 1 nonscarred cornea, 17 patients (30 eyes) were randomly assigned to a steep lens fitting protocol. After trial fitting with a standardized lens design demonstrating minimum apical clearance, lenses were dispensed whose base curve was 0.2 mm steeper than the minimum apical clearance lens. Patients were re-evaluated on a quarterly schedule concluding at 12 months. Changes in keratometry between baseline and 12 months identified unequal steepening of the flat and steep corneal curvatures, suggestive of corneal molding. Best corrected rigid lens visual acuity measures illustrated no significant changes over the course of the study. Clinically significant corneal compromise was transiently observed in some patients. Only 1 of 22 eyes completing the pilot study and fitted with apical clearance developed mild corneal scarring.

Adolescent↗

PubMed1985

Soft bifocal contact lenses for patients with nearpoint asthenopia.

Bifocal contact lenses have generally been considered solely for the presbyopic population. However, pre-presbyopic individuals with accommodative or vergence disorders who respond favorably to plus lenses at near may be good candidates for bifocal contact lenses. A group of ten non-presbyopic patients who manifest accommodative dysfunctions or near point esophoria were fit with the Ciba BI-SOFT contact lenses. Nearpoint accommodative and vergence findings were evaluated through both near point plus spectacle lenses and the bifocal soft lenses. Results indicate that the BI-SOFT bifocal contact lens was effective in changing the near point visual posture. However, poor distance vision acuity due to ghost images reduced the subjective success rate of the BI-SOFT lens on this non-presbyopic population.

Adult↗