What a trial lens is for
At a fitting, your fitter usually places one or more lenses from a diagnostic set on your eye. These are standard lenses in a range of sizes and depths. The fitter looks at how each one sits: how much fluid is between the lens and your cornea, where the edge lands on the white of the eye, and whether it centers. They then use those measurements, and often scans or photos, to design a lens for your eye. Our page on what a scleral lens fitting involves walks through the visits.
Some practices fit from scans or an impression of the eye with few or no trial lenses. See impression-based, scan-based, PROSE or standard for those routes.
Why trial lenses often feel worse
- They aren’t shaped to you. A diagnostic lens is the closest match from a set. Its edge may press in one area and lift in another. Your custom lens is designed to fix that.
- They usually lack your prescription. Vision through the trial is often blurrier until your fitter adds lenses in front to test the remaining correction. That’s an over-refraction, and the result goes into your final lens.
- Cleaning products and saline. Trial lenses are disinfected between patients. Wearers often trace stinging to residue, or to a fill saline that doesn’t suit them.
- No coating. Many final lenses get a surface treatment that a trial lens may not have. See what is a scleral lens surface coating?
- It’s your first time. A brand-new sensation, a cold saline, a nervous first insertion: all of that colors the first impression.
What a bad trial can still tell you
A trial isn’t meaningless. These are worth mentioning, because they help the design:
- Sharp pain, or pain in one specific spot.
- A lens that moves a lot when you blink or slides off center.
- Fog that appears within minutes.
- Redness that is much worse in one area.
- Double vision, distortion, or objects looking curved or enlarged.
None of these mean scleral lenses won’t work for you. They mean something needs changing, and your fitter needs to hear it.
What wearers say
This is one of the clearest themes from wearers. Many describe trial lenses as uncomfortable, scratchy, or stinging, and their custom lenses as a big improvement. Several say they put off scleral lenses for years after a bad office trial, and wish someone had told them the trial wasn’t representative.
But the custom lens isn’t always right the first time. Wearers commonly describe needing a few pairs before comfort and vision were dialed in, and some found their delivered lens was blurrier than the trial over-refraction suggested until the next adjustment. A minority found the opposite: a smaller stock trial lens felt better than a larger custom one, which led their fitter to change the size. See how many remakes is normal?
What to ask your fitter
- “How close is this trial lens to what you’ll order for me?”
- “What vision do you expect me to reach with the final lens?”
- “What would make you change the design after I get the first custom pair?”
- “Which solutions should I use with the new lenses, and should I clean them before the first wear?”
- “How long is the exchange or remake window, and when does it start?”
When it’s not normal
A trial lens or a new custom lens can feel strange, but some symptoms aren’t part of adjusting.
Common questions
My vision with the trial lens was worse than with my glasses. Is that a bad sign?
Not necessarily. Trial lenses usually don't contain your prescription, so your fitter measures the remaining correction with an over-refraction and builds it into the custom lens. Ask your fitter what vision they expect you to reach with the final lens, since that depends on your eye condition.
The trial lens stung. Will the custom one sting too?
Trial lenses are shared and disinfected between patients, and wearers often trace stinging to leftover cleaning product or to the fill saline used in the office. Your own lenses, cleaned with your own routine and rinsed well, often feel different. Stinging that continues with your custom lenses is worth reporting.
Can a short trial tell me whether scleral lenses will help my dry eye?
A brief trial is a limited test. Some people feel relief immediately; others don't, especially with a generic lens and office saline. Wearers often say they would have judged too early on the trial alone. Ask your fitter what a fair trial looks like for your eyes.