GP lens eye Rounds

OCULAR SURFACE DISEASE: Surface Wettability Case

Julie Song OD, FAAO, FSLS

History

• 29-year-old male with keratoconus presented for a scleral lens refit. The patient was wearing habitual scleral lenses that were approximately two years old. He also reported that the left lens was difficult to remove.
• Patient reported that vision had been foggy and he had to repeatedly take out, clean, and re-apply his lenses throughout the day.
• History of dry eye disease currently being managed by Xiidra 5% 1 gtt BID OU and preservative-free artificial tears before and after scleral lens wear.
• Patient is s/p wavefront-guided PRK after corneal cross-linking OU four years ago.

Examination

• Entering Visual Acuities (VAs): OD 20/25 -2, OS 20/100-1
• Slit Lamp Examination:

• Corneal Tomography Scans (Figure 1):

• Dilated Fundus Examination: unremarkable

Decision-Making Process

• Symptoms of fogging can be the result of multiple sources: post-lens tear film leakage, poor surface wettability, or insufficient tear film. It is important to distinguish what the root cause of fogging symptoms is.
• Post-lens tear film leakage ideally is identified after multiple hours of scleral lens wear with Lissamine Green that is painted over the central anterior surface of the scleral lens to give equal opportunity to travel across the entire scleral lens. Time is of the essence and it is important to quickly transition between both eyes to check all quadrants for leakage.
• Poor surface wettability can occur from normal wear and tear of the scleral lens, from continuous interaction with patients who have ocular surface disease, and from inappropriate use of various GP lens cleaning solutions. Surface wettability can be improved with changing the GP lens material and with the addition of Tangible Hydra-PEG coating.
• Insufficient tear film can produce symptoms of fogging as the tear film is the first refractive surface that light hits before it travels into the eye. When the tear film quality is poor, patients can experience visual blur and “fogging”. This is usually diagnosed with slit lamp examination of the tear film with and without lens wear, as well as asking the patient if their vision improves after blink.
• This patient’s fogging was not from leakage of post-lens tear film after checking with Lissamine Green, but rather due to poor wettability on the scleral lens surface and insufficient tear film quality.

Fitting and Evaluation

• Entering Habitual Scleral Lens Fit and Parameters:
  • OD: Power: +4.00D, Overall Diameter (OAD): 16.0mm; 3500 SAG; Base Curve Radius (BCR): 8.4mm; 34-42 toric edge; center thickness (CT): .42mm: VA: 20/25-2
    • Slightly decentered inferior
    • No movement
    • Central: 1:3/4 vault
    • Paracentral: 1:3/4 vault
    • Midperipheral: 1:1/2 vault
    • Limbal: 1:1/2 vault
    • Edges: alignment
    • Hash marks 3:30 and 9:30
    • No LG leakage, but poor surface wettability
  • OS: Power: +2.50D, OAD: 16.0mm; 3500 SAG; BCR: 8.4mm; 34-42 toric edge; CT: 400 microns: VA: 20/100-1
    • Slightly decentered inferior
    • No movement
    • Central: 1:1/2 vault
    • Paracentral: 1:3/4 vault
    • Midperipheral: 1:1/2 vault
    • Limbal: 1:1/2 vault
    • Edges: steep 360
    • Hash marks 3:00 and 9:00
    • No LG leakage, but poor surface wettability
• Trial 1
  • OD: Power: +2.00D, OAD: 16.0mm; 3500 SAG; BCR: 8.0mm; 34-42 toric edge; CT: 390 microns: Tangible Hydra-PEG; VA: 20/20-1
    • Slightly decentered inferior
    • No movement
    • Central: 1:3/4 vault
    • Paracentral: 1:3/4 vault
    • Midperipheral: 1:1/2 vault
    • Limbal: 1:1/4 vault
    • Edges: alignment
    • Hash marks 3:30 and 9:30
  • OS: Power: -1.00D, OAD: 16.0mm; 3500 SAG; BCR: 8.0mm; 34-42 toric edge; CT: .28mm: Tangible Hydra-PEG; VA: 20/30+2
    • Slightly decentered inferior
    • No movement
    • Central: 1:1/2 vault
    • Paracentral: 1:3/4 vault
    • Midperipheral: 1:1/2 vault
    • Limbal: 1:1/4 vault
    • Edges: alignment
• Complete resolution of microcystic edema on patient’s corneas OU. Significant improvement in patient’s visual quality and acuity OU.

Clinical Pearls

• When a patient reports symptoms of fogging, don’t automatically assume that there is an issue with the lens edge.
• Pay close attention to tear film quality and quantity with all contact lens wearers.
• Discuss lens material and coating changes with the patients and ensure they are using the appropriate solution to clean lenses.
• Tangible Hydra-PEG needs to be used with Tangible Clean, Unique pH, Boston Simplus, Clear Care, and Clear Care Plus Hydraglyde. Alcohol-based cleaners and Progent cannot be used with lenses that have been treated with Tangible Hydra-PEG; however, Tangible Boost can be prescribed to clean and maintain the lenses.