A 75-year-old male presented with a history of bilateral keratoconus and 34 years of wearing specialty GPs fitted in our clinic. His most recent fit was prior to the pandemic in June 2019. He could not tolerate lens wear due to poor vision and difficulty removing his left lens. Slit lamp examination with fluorescein uncovered lens adhesion OS. His lens parameters were:

Base curve (BC) 60.00D (5.62mm) x 45.00D (7.50mm); power –17.00D; diameter 9.8mm; back optic zone (BOZ) 6.5mm; material: fluorosilicone acrylate (FSA); Dk: 50

CASE RESOLUTION

The left lens had no movement with a crescent fluorescein pool pattern at the apex and no tear exchange. There was no corneal staining, but was observed to have a slight corneal indentation after lens removal.

He was refitted with specialty GPs with minor changes in lens parameters and increased peripheral asphericity with a larger blending zone. Lens adhesion OS ceased immediately upon refit. The new lens parameter for his left lens were:

BC 60.00D (5.62mm) x 45.00D (7.50mm); power –17.50D; diameter 10.8mm; BOZ 6.6mm; material: FSA; Dk: 75

His previous lens fit was four years and six months prior, which means he handled and cleaned his lenses approximately more than 2,250 times. Considering the mechanical force during rubbing while cleaning the lens and the possibility of the lens falling on a rough surface while handling resulted in potential compromise of the peripheral blending and edge contour. The new lens with slight parameters changes and a larger aspheric periphery was effective to prevent adherence.

DISCUSSION

A few theories have been proposed and discussed concerning the etiology of lens adherence (Eiden and Schnider, 1996)¹. One hypothesis was that lens flexure, negative pressure, tear film mucous adhesion, and patient lens care solution regimen play a role (Campbell and Caroline, 1996)².

Another study conducted with overnight GP wear demonstrated that lens binding is primarily patient-dependent (Swarbrick and Holden 1996)³.

A healthy, perfect fitting depends on intermediate and peripheral curves to allow tear exchange and adequate lens movement. A well-designed lens using aspheric, rather than spherical, intermediate and peripheral curves may be of utmost importance to prevent GP lens complications.

CONCLUSION

GP lens adhesion may occur by a combination of factors, however an optimal lens cornea relationship with a well-designed periphery and edge lift are important factors. It is also relevant to evaluate tear film quality with tear film breakup time and Schirmer’s test.

References

1. Eiden SB, Schnider C. Adherence of Daily Wear GP Contact Lenses. Contact Lens Spectrum. 1996 Feb;11.

2. Campbell R, Caroline P. Contact Lens-Induced Superior Limbic Keratoconjunctivitis. Contact Lens Spectrum. 1996 Jan;11.

3. Swarbrick HA, Holden BA. Ocular characteristics associated with rigid gas permeable lens adherence. Optom Vis Sci. 1996 Jul;73:473-81.