Scleral lenses can be life changing for patients with dry eye, irregular corneas, or other ocular surface disease. One of the most common challenges we face as specialty lens experts is when our patients encountering midday fogging with their scleral lenses, when vision gradually becomes cloudy after starting the day clear.
This fogging can happen for a few different reasons, and identifying the cause is key to improving it.
The Two Main Causes of Scleral Lens Fogging
In general, fogging tends to come from one or both of the following issues:
1. Debris accumulating under the lens
In many cases, fogging is caused by material collecting in the fluid reservoir between the lens and the eye. This can include inflammatory cells, proteins, and lipids that are shed from an unhealthy or inflamed ocular surface.
Common contributors include:
• Meibomian gland dysfunction.
• Ocular surface inflammation.
• Imperfect alignment of the scleral lens edge with the conjunctiva.
• Poor tear film quality prior to lens insertion.
2. Poor wetting of the front surface of the lens
In other cases, vision becomes cloudy because the front surface of the scleral lens is not maintaining a stable tear film. This is often related to a dysfunctional tear film that leads to poor lens wetting, causing the surface to become patchy or unstable over time.
This means fogging is not always under the lens. Sometimes it is actually happening on top of the lens.
what can help improve fogging
Because there are multiple causes, treatment is usually most effective when it is comprehensive and targeted.
Full dry eye management is essential
Use of preservative free artificial tears over the lenses
Improving the health of the ocular surface can significantly reduce debris formation under the lens.
This may include treatments that address:
• Meibomian gland function.
• Ocular surface inflammation.
• Tear film stability.
• Eyelid hygiene and bacterial load.
In office treatments and at home therapies are often used together to optimize the environment the lens sits on.
A key but often overlooked strategy is the regular use of preservative free artificial tears while wearing scleral lenses. Even if the eyes do not feel dry, the lens itself creates a protected environment that can mask symptoms of dryness.
Adding lubricating drops over the lens helps:
• Improve surface wetting.
• Reduce buildup of debris on the front surface.
• Enhance comfort and clarity throughout the day.
This is especially important because patients may not feel traditional dryness symptoms while wearing scleral lenses, even though the tear film over the lens surface may still be unstable.
when lens adjustments are need
If fogging persists despite good ocular surface management, adjustments to the scleral lens fit may also be necessary. This can include changes to vault, landing zone alignment, fluid reservoir characteristics, or when these fail, upgrading to an impression-based design to perfectly align with all the lumps and bumps on the sclera.
How Can we help?
Scleral lens fogging is usually multifactorial. It can result from debris accumulating under the lens, poor tear film stability on the front surface, or a combination of both.
The good news is that in most cases, it can be improved with a combination of ocular surface treatment, optimized lens care, and consistent use of preservative free lubricating drops during wear.
If you are experiencing fogging with your scleral lenses, a detailed reassessment can help identify the cause and improve long term clarity and comfort.
Dr. Andrea Lasby, OD, FAAO, FSLS, FCCSO
Dr. Lasby is a private practice clinician and partner at Mission Eye Care in Calgary. She is residency trained in corneal disease and custom contact lenses. She is also a well-renowned speaker and serves on the board of the Alberta Association of Optometrists.
