Halos, glare, and ghosting

What you might be seeing

• Halos: soft rings around lights, often most noticeable at night.
• Glare or starbursts: headlights and streetlights that bloom or throw out rays.
• Ghosting: a faint second image next to letters or edges, as if the outline is doubled.

These symptoms are worth taking seriously because they’re often fixable, and because they affect things like night driving.

Rule out the quick fixes first

Several everyday problems scatter light and can look like halos or ghosting:

• A bubble under the lens. See filling solution and air bubbles.
• Film, smudges, or scratches on the lens. See film and deposits on the lens.
• Lenses in the wrong eyes. See right and left lenses mixed up.
• Fog in the saline behind the lens, which builds over hours. See midday fogging.

If the symptoms persist with a clean, freshly filled lens in the right eye, the cause is more likely the fit or the optics.

When the lens sits off-center

A scleral lens is designed to sit centered over your cornea. If it rides a little low or off to one side, the optical center of the lens is no longer lined up with your pupil, and that can bring on halos and ghosting.

Research in healthy eyes gives some sense of what affects this. In a study of 10 young adults, lenses fitted with a deeper layer of saline behind them sat lower and more to the side than the same lenses with a shallower layer, while making the lens thicker or heavier did not substantially change centration.^[2] In a study of 20 people with regular corneas, a lens with a toric landing zone (an edge shaped to match an eye that isn’t perfectly round) centered better than a spherical one, though it didn’t completely remove decentration.^[3] These are small studies in healthy eyes, so they show what fitters can adjust, not what will happen in yours.

If you can see that your lens often sits off-center, see lens off-center, and tell your fitter.

When it’s the eye’s optics

With keratoconus and other irregular corneas, a standard scleral lens corrects a great deal of the blur, but not always all of it. A review of contact lens correction in keratoconus explains that rigid lenses often leave some residual optical irregularity, called higher-order aberrations, mostly coming from irregularity on the back surface of the cornea. Depending on the pattern, changes such as the shape of the lens optics, a small prism in the lens, or how much the lens vaults the cornea can improve vision.^[1]

What fitters can change

Depending on the cause, your fitter may:

• Redesign the landing zone so the lens sits more centrally, for example with a toric or quadrant-specific edge.
• Adjust the vault, the depth of saline between the lens and your cornea.
• Use a larger optic zone, the clear central part of the lens you look through.
• Add wavefront-guided optics. These lenses have a front surface shaped to correct the specific aberrations measured in your eye while wearing the lens. In interim results from a double-blind crossover trial of 31 eyes of 18 people with irregular astigmatism, wavefront-guided scleral lenses reduced higher-order aberrations by 56% on average compared with standard scleral lenses, and 17 of the 18 participants preferred them.^[4] They’re not yet common: in an international survey of scleral lens practitioners, 3% of lenses had optics designed to correct higher-order aberrations.^[5]
• Consider an impression-based or other custom design for eyes that are hard to fit with standard lenses.

Not every option is available everywhere, and each one usually means a new lens and another visit or two. It’s fair to ask your fitter which of these they offer and what they’d try first.

How to describe it to your fitter

Be specific. “Headlights have starbursts in my right eye, worse after about six hours” gives your fitter much more to work with than “my vision is off.” Note which eye, what you see, when it starts, and whether a refill helps.