Comparing the tonometers
Rebound tonometry measures without drops and without air. The two iCare instruments below use the same patented principle and publish the same accuracy; what separates them is how the patient has to be positioned.
Side by side
Measured quantities only. What each instrument does and does not have is in the next section, because a table cannot tell the difference between a figure a manufacturer has not published and a feature an instrument does not have.
Scroll the table sideways to see every column. The row labels stay put.
| Specification | IC200 Rebound TonometeriCare | IC100 Rebound TonometeriCare |
|---|---|---|
| Model | TA031 | TA011 |
| Measurement principle | Rebound tonometry (patented) | Rebound tonometry (patented) |
| Measurement range | 7–50 mmHg | 7–50 mmHg |
| Accuracy | ±1.2 mmHg (≤20 mmHg) / ±2.2 mmHg (>20 mmHg) | ±1.2 mmHg (≤20 mmHg) / ±2.2 mmHg (>20 mmHg), 95% tolerance interval relative to manometry |
| Repeatability | <8% coefficient of variation | <8% coefficient of variation |
| Positional freedom | 200° | Not published |
| Weight | 165g without batteries / 260g with batteries | 140g without batteries / 230g with batteries |
| Power | 4 × AA alkaline batteries (1.5V LR6) | 4 × AA alkaline batteries (1.5V LR6) |
What separates them
One paragraph per instrument, taken from its own product page. Each names a real alternative instead of listing features again.
IC200 Rebound Tonometer
If every patient you measure can sit upright at a slit lamp, the positional range is capability you will not use, and the IC100 does the same rebound measurement in a lighter handheld at a lower investment. The IC200's case is the patient who cannot come to the instrument. Count how often that happens in a month before deciding.
IC100 Rebound Tonometer
The IC100 measures upright. If you regularly need pressure on supine or reclined patients, that is the IC200's case; the IC100 may feel limiting there. It also does not replace Goldmann where applanation is the documented standard for a particular decision; it changes what pretest and screening cost you in time.
In the same conversation, not in the table
These belong in the same conversation, and each one has its published specifications on its own product page. They are named here instead of tabulated because they answer a different question than the instruments in the table above; the note against each says which. Putting them in the same columns would imply the figures are measured the same way.
- NT-510 Non-Contact TonometerNon-contact rather than rebound. Marco publishes a full specification table for it, and its range and working distance are on the product page, but it measures by air puff, so accuracy and repeatability are not established against the same reference as the two iCare instruments and the numbers do not belong in one column.
- AT-8 & AT-9 Applanation TonometersApplanation, mounted on the slit lamp. This is the reference standard the other three are compared against rather than a fourth alternative to them, and it publishes no weight or power figure because it is an accessory to a lamp.
- Tonoref II ARK with TonometryTonometry combined with autorefraction and keratometry in one pretest instrument. Its specification table is on the product page; it is left out here because a practice choosing it is making a pretest-workflow decision, not picking a tonometer.
Where these figures come from
Every figure below comes from the manufacturer’s own published materials, linked here so you can check any of them. Nothing is estimated or filled in to complete a row: where a manufacturer does not publish a number, the table says so. Configurations change, so I will confirm the current details before you order.
- IC200 Rebound Tonometer: iCare, reviewed 2026-09-05
- IC100 Rebound Tonometer: iCare, reviewed 2026-09-05
Dimensions are left out. The IC200 publishes them as W × H × L with axes labelled and the IC100 publishes three unlabelled ranges, so the two cannot be put in one row without assuming which axis is which.
Configurations and specifications change. Ask me to confirm before ordering.
Talk it through with me
Tell me how your practice handles this now and what you want it to do, and we can work through the options together. You do not need to have settled on a product first.