Why night driving is hard with an irregular cornea
An irregular cornea, from keratoconus, a transplant, or surgery, bends light unevenly. In daylight your pupils are small, which hides some of that. At night your pupils open wider and light passes through more of the uneven surface, so headlights can smear, streak, or double. Glasses can’t fully correct an irregular surface.
How scleral lenses help
A scleral lens arches over the cornea on a layer of saline, giving your eye a smooth new front surface. A 2025 review notes that scleral lenses improve vision and reduce the higher-order distortions (the uneven blur glasses can’t fix) in eyes with irregular astigmatism.[3]
For many people that shows up at night. In a small study of 14 people with keratoconus, quality-of-life scores improved after three months of scleral lens wear, including the driving part of the questionnaire.[1] That’s a small, single-site study, but it fits what fitters often hear.
Why some people still see halos or glare
Scleral lenses reduce distortion, but they don’t always remove all of it.
- Leftover distortions. A published case report describes a man with keratoconus who read 20/20 or better with scleral lenses yet saw halos and glare at night. Measurements showed leftover optical distortions, and a lens with customized optics (wavefront-guided) reduced them and his night vision complaints.[2] That’s one patient, but it shows that a good eye chart result doesn’t always mean comfortable night vision.
- An off-center lens or leftover astigmatism. A review of scleral lens assessment lists leftover astigmatism, lens flexing and rotation, fogging, poor surface wetting, and deposits as factors that can degrade vision with the lens on.[4] Several of these can be changed in the lens design.
- Fogging late in the day. Debris can build up in the fluid behind the lens over the day. In a study of 120 veterans who wore scleral lenses, 15.8% reported midday fogging or bubbles.[5] In a study of 157 keratoconus eyes, fogging of the fluid reservoir was recorded in 7.0%.[6] If you drive home in the evening, that timing matters.
- Multifocal designs. In a small study comparing a single-vision and a multifocal version of the same scleral lens, distance vision in dim light was weaker with the multifocal.[7]
For more on symptoms that don’t clear up, see vision still not perfect with sclerals.
What you can do
- Describe what you see, specifically. “Headlights have a starburst in my right eye after 7 pm” is more useful than “night vision is bad.”
- Ask about fogging. If evening vision is milky, ask your fitter whether a planned removal, clean, and refill before you drive suits you, and whether the fit can be adjusted.
- Keep the lens surface clean. Film and deposits scatter light. Follow your cleaning routine and replace lenses when your fitter advises.
- Keep backup glasses in the car. The FDA advises every contact lens wearer to have a backup pair with a current prescription.[8]
- Don’t push it. If your vision fogs or feels unsafe while you’re driving, pull over somewhere safe and switch to glasses, or stop driving for the day.
Questions to ask your fitter
- “Is my lens centered well, and could that cause halos?”
- “Do I have leftover astigmatism or distortion you could correct in the lens?”
- “Would customized optics help my night vision?”
- “What’s causing my fogging, and what can we change?”
Common questions
I read 20/20 with my lenses. Why are headlights still starry?
The eye chart measures sharpness in good light, on high-contrast letters. At night your pupils are larger and small leftover distortions in the optics show up more. A published case describes exactly this: a keratoconus patient who read 20/20 with scleral lenses but saw halos and glare at night, which improved with a customized lens. Tell your fitter what you see.
Should I take my lenses out before a long evening drive?
If your vision is fogging by evening, a removal, clean, and refill with fresh saline before you set off may help, if your fitter has shown you how. If your vision still isn't good enough, drive in your glasses or don't drive. Ask your fitter about a plan that fits your schedule.
Are multifocal scleral lenses OK for night driving?
They may be harder. In a small study, distance vision in dim light was weaker with a multifocal scleral lens than with a single-vision version of the same lens. If you drive a lot at night, raise this with your fitter before choosing a multifocal design.