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Add-on IOL calculator by MIOLO
Supplementary sulcus IOL power for pseudophakic eyes
Pseudophakic eye with a stable IOL in the bag. After capsule rupture, use Sulcus.
Keratometry
Cornea to the primary IOL; used only for the eligibility check.
Surgical planning
Optional; fill both or neither.
Supported supplementary lenses
- Sulcoflex Aspheric (IOL700L): -10.0 to +10.0 D, 0.5 D steps
- Sulcoflex Toric (IOL710T): -7.0 to +7.0 D, 0.5 D steps; cylinder +1.0 to +6.0 D, 0.5 D steps
- Sulcoflex Trifocal (IOL703F): -3.0 to +3.0 D, 0.5 D steps (0.25 D within ±1.0 D); addition +3.50 D near, +1.75 D intermediate
- 1stQ AddOn Refractive (A4SW00): -10.0 to +10.0 D, 0.25 D steps
- 1stQ AddOn Toric (A4TW/A4FW): -10.0 to +10.0 D, 0.25 D steps; cylinder 1.0 to 11.0 D in non-uniform steps (1.0, 1.5, 2.25, 3.0, 3.75, 4.5, 5.25, 6.0, 6.75, 7.5, 8.25, 9.0, 10.0, 11.0 D); at 11.0 D sphere is limited to -3.0 to +8.0 D
- 1stQ AddOn Trifocal (A4DW0M/A4EW0M): -5.0 to +5.0 D, 0.25 D steps; addition +3.0 D near, +1.5 D intermediate
- 1stQ AddOn Trifocal Toric (A4HW0M): -3.0 to +3.0 D, 0.5 D steps; cylinder +1.0 to +4.5 D, 0.5 D steps; addition +3.0 D near, +1.5 D intermediate
- 1stQ AddOn EDOF +1,75 (A4DW0H/A4EW0H): -5.0 to +5.0 D, 0.25 D steps; addition +1.75 D
- 1stQ AddOn EDOF +2,25 (A4DW0K): 0.0 D only; addition +2.25 D
Each family is calculated within the ranges and step sizes that its manufacturer publishes.
Frequently asked questions
How is the supplementary (add-on) IOL power calculated?
From the eye's current residual refraction, the vertex distance and, for a toric family, the surgically induced astigmatism of the primary incision.
Are add-on, supplementary and piggyback IOL the same thing?
Yes. Add-on, supplementary and piggyback IOL are different names for the same concept: a second lens implanted in the ciliary sulcus of a pseudophakic eye, in front of a stable primary IOL in the capsular bag.
Do I need a full biometry work-up to use this calculator?
No. Because the primary IOL is already in place, the calculation uses the eye's current refraction and keratometry, not a full pre-cataract biometry. The pseudophakic anterior chamber depth is asked for the eligibility check, not for the lens power: a supplementary lens sits in the ciliary sulcus, whose position does not follow the depth of the primary lens in the bag.
Can this calculator correct astigmatism?
Yes, with a toric add-on family. The surgically induced astigmatism of the incision and its axis are required inputs, and the recommendation includes the implantation axis.
Do I need an account, registration or patient data to use it?
No. The calculator is free and open: no account, no registration, and no surgeon, patient or institution data are required to calculate. Signed-in surgeons can optionally save the result to their own case records.
About MIOLO Add-on
MIOLO Add-on is a free calculator for the power of a supplementary (add-on or piggyback) IOL in the ciliary sulcus of a pseudophakic eye, from the current residual refraction.
What it is for
It turns the residual refraction of an eye that already has a stable lens in the capsular bag into the power of a second lens for the ciliary sulcus, spherical or toric, without removing the primary lens.
Who it is for and when to use it
It is built for cataract and refractive surgeons treating a refractive surprise or a residual error after cataract surgery, once the refraction is stable and a supplementary lens is being considered.
What you enter
The lens family, the current manifest refraction (sphere, cylinder and axis) with its vertex distance, K1 and K2 keratometry, the pseudophakic anterior chamber depth (ACD) for the eligibility check, the target, the surgically induced astigmatism (SIA) with the incision axis for a toric family, and whether there was a previous keratoplasty. The axial length (AL) and the primary IOL power are kept for the record only.
What you get
The supplementary IOL power, with cylinder and implantation axis for a toric family, a table of add-on power options, clinical notes derived from the data you entered, and, for signed-in surgeons, the option to save the case.
Frequently asked questions
- Which refraction should I enter?
- The current manifest refraction at the spectacle plane, with the vertex distance at which it was measured.
- Does it work on mobile?
- Yes. The page adapts to phones and tablets, and the result reads the same as on a desktop.
Further reading
The calculator supports, and does not replace, the surgeon's clinical judgment.