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Dear colleagues, I am making this simple online calculator available to answer the question that most often stalls candidate selection for the EyeMax Mono IOL (SharpView Ophthalmology): is my patient’s maculopathy larger or smaller than 10°?
Please note: the 10° quoted by the manufacturer and in the literature are not the lesion diameter, but a RADIUS — the maximum eccentricity from the foveal centre within which the lens’ hyperaspheric optic optimises the image.
The calculator converts the anatomical measurements we already collect in the clinic — the lesion diameter on OCT, the atrophy area on autofluorescence (FAF), or the optic disc comparison on a fundus photo — into degrees of radius from the foveal centre, applying axial-length correction (Bennett-Littmann). The result is the value to enter into the official EyeMax Mono Selector Tool.
Privacy: all calculations are performed locally in the browser. No patient data is transmitted, recorded or stored on this website.
What you need: the patient’s axial length (AL) and ONE measurement of the macular lesion.
Please note — visual acuity is NOT enough. Visual acuity measures the resolution threshold of the best residual retinal point, not the extent of the damage: there is no validated VA → scotoma-degrees formula in the literature. Using visual acuity as a surrogate for the 10° cut-off is methodologically incorrect.
Professional tool · Ophthalmology
The mm→degree conversion depends on axial length (Bennett-Littmann correction).
Select ONE mode. In modes 1 and 3 you enter the lesion DIAMETER; the calculation uses the radius (÷2). Mode 2 uses the area (mm²).
Live formulas, identical to the practice’s Excel worksheet.
◔
| Scotoma radius | Outcome |
|---|---|
| ≤ 9° | ELIGIBLE — wide margin |
| 9° – 10° | BORDERLINE — confirm with 10-2 VF / MAIA / MP-3 |
| 10° – 12° | BORDERLINE — assess case by case |
| > 12° | NOT eligible |
| Lesion diameter | Lesion radius | RADIUS in degrees | Diameter in degrees |
|---|---|---|---|
| 1.5 mm | 0.75 mm | 2.5° | 5.0° |
| 3.0 mm | 1.50 mm | 5.0° | 10.0° |
| 4.5 mm | 2.25 mm | 7.5° | 15.0° |
| 6.0 mm | 3.00 mm | 10.0° | 20.0° ← CUT-OFF EyeMax |
| 9.0 mm | 4.50 mm | 15.0° | 30.0° |
Formal pure Bennett equivalent: q = 0.01306 × (AL − 1.82). With DP = 1.50 mm the mode 3
formula matches (LL/2)/corrected mm/° of the Excel worksheet. Beware the Humphrey
“10-2”: the 10-2 grid tests a square area of 10°×10° (5° radius per axis):
the EyeMax calculation needs the MAXIMUM scotoma extension from the grid centre.
| # | Case | Setup (AL / measurement / mode) | Scotoma (radius °) | Outcome |
|---|---|---|---|---|
| 1 | Full GA, emmetrope | AL 24.46 / DL 6.0 mm / Mode 1 | 10.00 | BORDERLINE |
| 2 | Small atrophy, emmetrope | AL 24.46 / DL 3.0 mm / Mode 1 | 5.00 | CANDIDATO ampi margini |
| 3 | 5 mm atrophy, emmetrope | AL 24.46 / DL 5.0 mm / Mode 1 | 8.33 | CANDIDATO ampi margini |
| 4 | Myope with GA | AL 26.00 / DL 5.5 mm / Mode 1 | 8.62 | CANDIDATO ampi margini |
| 5 | Disc comparison (2 DD) | AL 24.00 / LL 3.0 mm / DP 1.5 mm / Mode 3 | 5.10 | CANDIDATO ampi margini |
| 6 | Disc comparison (3 DD) | AL 24.00 / LL 4.5 mm / DP 1.5 mm / Mode 3 | 7.64 | CANDIDATO ampi margini |
| 7 | GA by area (AF) — small | AL 24.46 / Area 4 mm² / Mode 2 | 3.76 | CANDIDATO ampi margini |
| 8 | GA large area | AL 24.46 / Area 28 mm² / Mode 2 | 9.95 | BORDERLINE |
Report generated by the online calculator — Dr. Alberto Bellone, Ophthalmologist and Eye Surgeon
| Patient data | |
|---|---|
| Surname and first name | — |
| Examination date | — |
| Eye | — |
| Visual acuity (BCVA) | — |
| Diagnosis / notes | — |
| Calculation | |
|---|---|
| Axial length (AL) | — |
| mm/° corrected | — |
| Measurement mode | — |
| Entered measurement | — |
| Lesion radius | — |
| Scotoma extension (RADIUS) | — |
| Equivalent diameter in the visual field | — |
| EyeMax Mono eligibility outcome | — |
Cut-off: scotoma RADIUS ≤ 10° = 3 mm = 2 DD (SharpView,
Badalà 2024, Hengerer 2025). Conversion: 1° ↔ 0.300 mm (Drasdo-Fowler 2007) with Bennett-Littmann
correction for AL. Clinical-educational tool: it does not replace the surgeon’s judgement
nor the official SharpView selector.
A radius. All primary sources agree: 10° = eccentricity from the foveal centre = 3 mm of retina = 2 disc diameters. The anatomical check is immediate: the macula measures about 5.5–6 mm in diameter, so a 10° radius (3 mm) matches the radius of the useful macular area. If the 10° were a diameter, the optic would cover only 1.5 mm of radius — essentially the fovea alone — incompatible with the lens’ goal of optimising extrafoveal PRLs.
No — beware the double meaning of the number “10”. The 10-2 grid tests a square area of 10° × 10°: “10°” is the side of the square, i.e. a 5° radius along each axis. The 10-2 is very useful for characterising the scotoma, but for the EyeMax decision you must measure the maximum scotoma extension from the grid centre, not the side of the test. In borderline cases (9°–12°) the calculator specifically recommends supplementing with 10-2 VF, MAIA or microperimetry.
Microperimetry (Nidek MP-3, MAIA CenterVue, MP-1) is the gold standard: it measures retinal sensitivity point by point on a grid already expressed in degrees of visual angle, with eye tracking, and directly provides the scotoma radius with no conversions. The calculator is useful when starting from anatomical measurements (OCT, FAF, fundus photos) or for a quick first estimate.
At the foveal centre the classic rule applies: 1° ≈ 0.300 mm of retinal tissue (273 µm per Drasdo & Fowler 2007, Vision Research), corrected for axial length: mm/° = 0.300 × (AL / 24.46). In practice: in a myopic eye (AL 26 mm) one millimetre subtends fewer degrees; in a hyperopic eye (AL 22 mm) it subtends more. This is why entering the real AL — rather than the standard value — can change the outcome in cases near the cut-off.
Yes — it is the “bedside” method of mode 3: on a fundus photo or an en-face OCT containing both the lesion and the optic disc, measure both and use the proportion (1 disc ≈ 1.5 mm ≈ 5° diameter). It is an estimation method: for cases near the cut-off, confirmation with calibrated OCT or microperimetry is still recommended.
No. The official SharpView selector remains the final decision-making tool and requires professional registration. This calculator prepares the hardest value to obtain — the maculopathy extension in degrees of radius — to then enter into the selector.
No. The calculator runs entirely in the browser: no data leaves the computer, no cookies, no tracking. The patient fields are only used to compose the printable report.
SharpView Ophthalmology (Patient Selection); Robbie SJ et al., J Refract Surg 2018 (pilot study); Badalà F et al., OPTH 2024; Hengerer FH et al., BMC Ophthalmol 2025 (European multicentre study, 196 eyes); Drasdo N & Fowler CW, Vision Research 2007; the Bennett-Littmann formula for retinal magnification. The full list with links is in the calculator’s “Bibliographic sources” section.
