Advertisement

PentaVision

Contact Lens Spectrum

Article

THE SCLERAL LENS VAULT

CLOUDY WITH A CHANCE OF FOG

By: KAREN LEE, OD
Contact Lens Spectrum May 1, 2022 Vol 37, Issue May 2022 Page(s): 44, 45

A common complaint that scleral lens patients report is reduced visional acuity as they wear their lenses (Fadel, 2019). This nuisance can range from mild annoyance to completely debilitating. Uncovering the source of blur requires a systematic approach and careful observation. Below is a list of differential diagnoses to consider along with various treatment and management tips.

Poor Front-Surface Wetting

  • Signs and Symptoms Visual blur may occur immediately after lens application or slowly throughout the day with increased wear time. Ask patients whether blinking helps because the windshield wiper effect of the eyelids temporarily refreshes the tear film. Careful slit lamp observation of the surface may clarify the root of the problem, which could be non-compatible makeup use, lens surface deterioration, poor tear film quality, or incomplete blinking (Figure 1).

    Figure 1. White deposits accumulate on the scleral lens surface.
    Figure 1. White deposits accumulate on the scleral lens surface.
  • Treatment and Management Start fresh with a new lens if scratches are observed and consider integrating a polyethylene glycol (PEG) coating that has been shown to resist surface deposits and increase lens wettability (Sindt, 2016). Emphasize the importance of manually rubbing with lens cleaner to loosen the debris prior to disinfection. Weekly enzymatic protein removers may benefit heavy depositors. Recommend contact lens-compatible makeups that are water-soluble and increase preservative-free artificial tear (PFAT) use with frequent blinking to restore the pre-lens tear layer. Ocular surface disease should be concomitantly treated to improve tear film quality and quantity.

Midday Fogging (MDF)

  • Signs and Symptoms Gradual visual blur often occurs slowly throughout the day with lens wear. Blinking and PFAT use provide minimal relief, but vision improves immediately with lens removal and reapplication. A murky tear reservoir can be seen with slit lamp (Figure 2) and anterior chamber optical coherence tomography (OCT) (Figure 3). Particulate matter appears white, brown, or yellow and may be the result of epithelial sloughing, inflammatory by-products, or lipid accumulation (Schornack et al, 2020; Carrasquillo et al, 2017; Walker, 2014; van Diepen et al, 2013).

    Figure 2. A cloudy tear reservoir is observed under a lens with excessive clearance.
    Figure 2. A cloudy tear reservoir is observed under a lens with excessive clearance.

    Figure 3. A turbid tear reservoir is observed after four hours of lens wear. Photo courtesy of Maria Walker, OD
    Figure 3. A turbid tear reservoir is observed after four hours of lens wear. Photo courtesy of Maria Walker, OD
  • Treatment and Management Scleral lens design best practices to mitigate MDF are still up for debate (McKinney et al, 2013; Carracedo et al, 2017). In the meantime, practitioners should optimize the scleral lens fit by aiming for approximately 200µm of apical clearance, 60µm of limbal clearance, and circumferential haptic alignment post lens settling (Harthan et al, 2021). This should decrease negative suction forces observed with tightly fit lenses and decrease any pumping action that may occur with haptic misalignment (DeNaeyer et al, 2017). Incorporating a viscous PFAT in the bowl of the lens prior to application and advising against vigorous eye rubbing while wearing lenses may decrease ocular surface inflammation by decreasing friction between the lens and eye (Fogt, 2021). Filling solutions designed specifically for scleral lens wear may also provide symptomatic improvement.

Corneal Edema

  • Signs and Symptoms Gradually decreased vision with glare and halos often occurs with increased lens wear. Vision improves minimally even with lens removal and reapplication and may persist for several hours after lens wear. A hazy or thickened cornea can be observed with biomicroscopy (Figure 4) or global pachymetry. Patients who have a compromised endothelial cell count of 800 cells/mm2 or less are at the greatest risk of developing corneal edema with scleral lens wear (Fadel and Kramer, 2019).

    Figure 4. Corneal haze can be seen behind the tear lens reservoir in a patient who has Fuchs’ dystrophy.
    Figure 4. Corneal haze can be seen behind the tear lens reservoir in a patient who has Fuchs’ dystrophy.
  • Treatment and Management Optimize oxygen transmission by utilizing high-Dk materials, keeping the tear reservoir and lens center as thin as possible, and increasing tear exchange with lens fenestrations (Ezekiel, 1983). Some patients may only tolerate intermittent lens wear for short periods of time to prevent corneal exhaustion. Topical hyperosmotic drops or ointments before and after lens wear can facilitate fluid regulation. It is important to stress the dangers of long-term corneal edema with patients, as it can lead to permanent vision loss or transplant failure.

Managing decreased vision with scleral lens wear can feel like a daunting task that requires much trial and error. Careful observation and a thorough history are crucial in order to resolve this regular problem. CLS

References

  1. Eye & Contact Lens: Science & Clinical Practice: May 2019 - Volume 45 - Issue 3 - p 152-163 doi: 10.1097/ICL.0000000000000523
  2. Sindt C. Evaluation polyethylene glycol surface coating on gas permeable lenses to improve wearability and wettability. Invest Ophthalmol Vis Sci 2016;57: E-Abstract 1462.
  3. Schornack MM, Fogt J, Harthan J, et al. Factors Associated with Patient-Reported Midday Fogging in Established Scleral Lens Wearers. Cont Lens Anterior Eye. 2020 Dec;43:602-608.
  4. Carrasquillo KG, Lipson MJ, Ezekiel DJ, Johns LK. Scleral Lens Complications and Problem Solving. In: Barnett M, Johns LK, eds. Ophthalmology: Current and Future Developments. Bentham Science Publishers; 2017:303-345.
  5. Walker M. Scleral Lenses: Clearing the Fog. I-Site. 2014 Oct. Available at http://www.netherlens.com/october_2014 . Accessed March 30, 2022.
  6. van Diepen JA, Berbée JFP, Havekes LM, Rensen PCN. Interactions between Inflammation and Lipid Metabolism: relevance for Efficacy of Anti-Inflammatory Drugs in the Treatment of Atherosclerosis. Atherosclerosis. 2013 Jun;228:306-315.
  7. Harthan JS, Schornack M, Nau CB, Nau AC, Fogt JS, Shorter ES. Current U.S. based optometric scleral lens curricula and fitting recommendations: SCOPE educators survey. Cont Lens Anterior Eye. 2021 Jun;44:101353.
  8. McKinney A, Miller W, Leach N, Polizzi C, van der Worp E, Bergmanson J. The Cause of Midday Visual Fogging in Scleral Gas Permeable Lens Wearers. Invest Ophthalmol Vis Sci. 2013 Jun;54:5483.
  9. Carracedo G, Serramito-Blanco M, Martin-Gil A, Wang Z, Rodriguez-Pomar C, Pintor J. Post-lens tear turbidity and visual quality after scleral lens wear. Clin Exp Optom. 2017 Nov;100:577-582.
  10. DeNaeyer G, Sanders DR, Farajian TS. Surface coverage with single vs. multiple gaze surface topography to fit scleral lenses. Cont Lens Anterior Eye. 2017 Jun;40:162-169.
  11. Fogt JS. Midday Fogging of Scleral Contact Lenses: Current Perspectives. Clin Optom (Auckl). 2021 Jul 21;13:209-219.
  12. Fadel D, Kramer E. Potential contraindications to scleral lens wear. Cont Lens Anterior Eye. 2019 Feb;42:92-103.
  13. Ezekiel D. Gas permeable haptic lenses. J British Contact Lens Association. 1983 Oct;6:158.

Dr. Lee is a clinical assistant professor at the University of Houston College of Optometry. She is also the past president of the Scleral Lens Education Society. She has received travel funding and lecture or authorship honoraria from Alcon and Bausch & Lomb.

What to Read Next