Paolo Presby-AI

Patient-specific multifocal optics

A personalised pseudo-accommodative profile designer for presbyopic LASIK / PRK: wavefront-guided, pupil-aware, vergence-range-driven. Built around a rigorous optical engine - OPD sag conventions, Zernike rescaling between pupils, FFT-based through-focus MTFa scoring, and a dual-pupil optimiser.

by Dr. Abdel Rahman Abuzaid, MD · powered by Paolo AI · oculoplasty.app

Why this designer exists

Every presbyopic excimer profile in clinical use works the same optical lever: reshaping the eye's spherical aberration to extend depth of field, programmed either as a change in corneal asphericity (Q) or as radial Zernike targets (Z40, Z60, Z80). Commercial modules rarely personalise this to the patient's own higher-order wavefront and pupil behaviour.

Paolo Presby-AI co-designs the treatment around this eye: its refraction, its keratometry and asphericity, its measured HOAs, and the two pupil sizes that matter clinically - the mesopic distance pupil and the miotic near pupil driven by the accommodation-convergence reflex. The optimiser scores every candidate by FFT-computed through-focus image quality at both pupils simultaneously.

No nomogram. No template. The physics adapts to the eye, not the other way around.

What the engine computes

Biconic strategy - Levenberg-Marquardt calibrated ΔK of the corneal surface, converting a target Q change into laser-entry Sphere / Cylinder / Axis.
Modal strategy - radial Zernike target (Z20 / Z40 / Z60 / Z80) with sequential pattern-search refinement on each mode.
Scoring - through-focus MTFa (area under the radial MTF, 10-50 lp/mm) computed by FFT at every candidate, depth-of-focus width, distance and near floors, fragmentation and peak-drift penalties.
Outputs - laser-entry contract, idealised ablation map + meridional profile, three vergence maps, Zernike SA table, through-focus MTFa curves, PSF strip and letter-E convolution.

Disclaimer

Paolo Presby-AI is an educational and research-oriented simulation. It is not a certified medical device and must not be used to plan or execute treatment on real patients. All results are theoretical and indicative; the surgeon's nomogram and the laser platform's own calibration bridge the gap between an optical design and a delivered treatment.

References

Gatinel D, Malet J. Vergence-based ocular wavefront expansions in diopters. J Opt Soc Am A. 2025;42(12):1846-63.
Rahmania N, Salah I, Rampat R, Gatinel D. Clinical effectiveness of laser-induced increased depth of field for simultaneous correction of hyperopia and presbyopia. J Refract Surg. 2021;37(1):16-24.
Courtin R, Saad A, Grise-Dulac A, Guilbert E, Gatinel D. Changes to corneal aberrations and vision after monovision using a customized aspheric ablation profile to increase corneal Q. J Refract Surg. 2016;32(11):734-41.
Gatinel D, Hoang-Xuan T, Azar D. Determination of corneal asphericity after myopic ablative surgery. J Cataract Refract Surg. 2006.

Step 1 - Patient data. Enter the standard presbyopic-LASIK workup: spectacle refraction (with vertex distance), keratometry with asphericity on each meridian, the optical zone, and the two pupils used for scoring. All fields are editable - explore any presentation.

Eye

Spectacle refraction to correct

S (D)Sphere

C (D)Cylinder (negative)

Axis (°)

Vertex (mm)

Corneal-plane refraction

S: - D C: - D

auto

Pre-op corneal data

K1 (D)flat meridian

Axis A1 (°)

Q1asphericity A1

K2 (D)steep meridian

Axis A2 (°)auto: A1+90

Optical zone & reduced eye

OZ (mm)

Focal length (mm)reduced eye

Step 2 - Wavefront analysis. The Zernike pyramid shows the high-order modes as an aberrometer would report them (source pupil 6 mm by default). Vergence maps convert the wavefront into local optical power in diopters - the clinically meaningful reading for multifocal design. No aberrometry? Use typical Z(4,0): +0.10 μm at 6 mm, the population mean for primary spherical aberration.

Zernike HOA pyramid (μm @ 6 mm)

HOA wavefront map (μm)

Radial vergence maps (D)

Total (low + HOA) - what the eye does now

Low order only - the spectacle correction

HOA only - the optical residue a lens cannot fix

V ≈ −(∂W/∂r)/r in diopters. A central myopic (negative) zone reads as near focus; a plano periphery reads as distance. This is the working unit of multifocal design.

Step 3 - Treatment design. Two domains: the optical domain (the vergence range the treated eye should cover) and the spatial domain (the two pupils: large mesopic pupil scored at the far end, small miotic near pupil scored at the near end - via the accommodation-convergence-miosis triad). Then choose the programming route that matches your laser.

Optical domain - target depth of focus

Far end (D)

Near end (D)

Step (D)

Spatial domain - pupil pair

Upper pupil (mm)mesopic / distance

Lower pupil (mm)near miosis

Pupil sweepscoring pupils

Distance vision is scored on the upper pupil at the far end of the range; near vision on the lower pupil at the near end. Intermediate pupils are swept and averaged.

Optimization strategy

SELECTED

Q (asphericity) modulation

Sphere / Cyl / Axis + ΔQ target

Programmes a clinical refraction plus a target post-op corneal asphericity. The ΔQ shift produces the spherical-aberration change that extends depth of field. LM-calibrated ΔK converts optics into laser entry.

Click to switch

Spherical-aberration modulation

Radial Zernike target (Z40 / Z60 / Z80)

Programmes a radial Zernike wavefront target. Sequential pattern-search shapes Z40/Z60/Z80 for finer control of the through-focus plateau. Suited to wavefront-guided platforms.

Z40 half-range ± (μm)

Z60 half-range ± (μm)

Z80 half-range ± (μm)

Step 4 - What the optimiser is doing. A coarse grid over the strategy's parameters is scored by full FFT through-focus evaluation at the scoring pupils; a pattern search then refines around the best cell. The heatmap shows the score landscape and the search trail.

Starting optimization...

Search landscape

Step 5 - Results. (A) what to program, (B) predicted vergence outcome, (C) expected through-focus performance, (D) ablation profile and optimisation audit. All values are theoretical targets inside the optical zone - your nomogram and platform calibration bridge the gap to the delivered treatment.

A - Laser entry

Sphere (D)

Cylinder (D)

Axis (°)

Q1 target

Q2 target

ΔQ (post - pre)

B - Predicted vergence outcome (D)

1 - to correct (pre-op)

2 - treatment-induced change

3 - post-op residual

C - Expected through-focus performance

DoF (D)

Peak MTFa

Peak Strehl

Sphere add (D)

Through-focus MTFa - upper (blue) vs lower (orange) pupil. Pink band = usable DoF.

PSF strip at best focus (log scale)

Letter-E convolution across defocus (20/20, physically calibrated retinal size) - what the patient would read.

D - Zernike spherical-aberration table

Coefficient	Pupil (mm)	Pre-op (μm)	Post-op (μm)	Δ

D - Ablation profile (idealised, inside OZ)

Exact tissue subtraction z_pre - z_post (n = 1.376), inert cornea. Transition zone, epithelial remodelling, biomechanics and laser-specific spot profiles are NOT modelled.

Ablation depth map (μm)

Meridional profile (0°)

Max ablation (μm)

Central ablation (μm)