GP lens eye Rounds

Corneal GP Spherical Lens Troubleshooting

Ed Bennett OD, MSEd, FAAO, FSLS

The three primary troubleshooting problems and their management are listed below:

Inferior Decentration

This is the first problem to consider as it represents a causative factor for the other two problems.

• Causes:
  • Thick lens design
  • High edge clearance
  • Low corneal apex
  • High corneal astigmatism
• Management¹:
  • Reduce center thickness (i.e., ultrathin design)
  • Proper edge design (- lenticular for all plus and ≤ – 1.50D powers; + lenticular for ≥ -5.00D)
  • Bitoric for ≥ 2.50D corneal astigmatism
  • Strive for lid attachment with a low-medium edge clearance design

Corneal Desiccation (3 & 9 o’clock staining)

Corneal desiccation or drying/desiccation of the exposed peripheral 3 & 9 o’clock areas of the cornea (Figure 1) has several causes but the incidence is much less today due to the management options listed below.²

• Causes:
  • Inferior decentration resulting from the causes listed under #1.
  • Poor surface wettability/ocular surface disease

Figure 1: Grade 2 corneal desiccation

• Management:
  • Optimize centration through aforementioned methods (i.e., reduce center thickness, lenticular if applicable, reduce edge clearance, bitoric if high corneal astigmatism)
  • Reorder with Tangible Hydra-PEG coating
  • Manage ocular surface disease if present

Poor Surface Wettability

This can be both initial and acquired.

• Initial poor surface wettability.
  • Causes:
    • Residual laboratory polish on lens
    • Other residues from manufacturing process
  • Management:
    • Use of laboratory/extra-strength cleaner (assuming PEG -based coating not present)
• Acquired poor surface wettability:
  • Causes:
    • Poor compliance with daily care and cleaning
    • Ocular surface disease
    • Use of lanolin-containing hand creams and/or soft soaps prior to handling the lenses
  • Management:
    • Patient education: importance of cleaning in the palm of the hand upon removal every night and soaking in the recommended solution. Also, not to use a lanolin-containing soap or lotion prior to handling lenses
    • Recommend a hydrogen peroxide disinfection system
    • Reorder with the Tangible Hydra-PEG coating and prescribe Tangible Boost for monthly refreshing of the lens coating.

Sources

1. Bennett ES, Scheid T, Morgan BW. Gas-Permeable Lens Problem-Solving. In Bennett ES, Henry VA. Clinical Manual of Contact Lenses, 5th ed., Wolters Kluwer, Philadelphia, PA, 2020: 227-254.
2. Azhar J, Bennett ES, Castellano CF. Corneal desiccation in today’s contact lens wearers: results. Contact Lens Spectrum 2015;30(11):17.