Bimini AI
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Refractive · WaveLight EX500

LASIK Nomogram

Enter the clinic manifest refraction and age. Sphere follows the house age policy — leave the young a little plus, tapering to plano by 40. Cylinder uses a pullback fitted to operated EX500 eyes.

Clinic manifest refraction

± sets the sign
minus-cyl (± to flip)

Program into the EX500

–sphere
–cylinder
–axis

Reasoning

    Findings

    What the 717-eye outcomes show. Confirmed findings drive the engine; the divergent one is flagged for outcome validation.

    FindingWhat the data showsStatus
    Sphere adjustment (median)−0.25 D✓ confirmed
    Age effect is myope-specificcorr(age): myope +0.41, hyperope +0.08✓ confirmed
    Older → leave less minus>50 yr myopes pulled toward plus✓ confirmed
    Cylinder treated77% myope / 85% hyperope (pulled back)⚠ validate on outcomes
    Accuracy ceiling~0.2 D irreducible sphere scatter✓ noise floor
    drives the age hedge — no separate age field
    Parses automatically as you paste — then tap a card to drop it into an eye.

    ● OD — right eye

    minus-cyl (± to flip)
    "auto" = age taper · +0.50 ≤22 · +0.25 to 40 · plano after. Or type an SE (0 = plano).
    Override — blank uses the nomogram

    ● OS — left eye

    minus-cyl (± to flip)
    "auto" = age taper · +0.50 ≤22 · +0.25 to 40 · plano after. Or type an SE (0 = plano).
    Override — blank uses the nomogram
    Prospective study — log this case Bimini rec is captured automatically from the plan above. Add what IBRA chose + what was programmed.
    ● OD — IBRA (clinic) chose
    ● OS — IBRA (clinic) chose
    Enter each eye separately. Leave Target SE on "auto" to use the nomogram's age hedge, or type a number (e.g. −0.50) to set an explicit target — the two never stack.
    Live preview — updates as you type · this is exactly what prints

    Cases awaiting post-op. Enter the manifest refraction + VA from the ~2-month nomogram visit — the 1-day and 1-week encounters record VA only, and an uncorrected VA cannot score a nomogram because it discards the sign of the error. That closes the loop so each nomogram can be scored against the achieved outcome.

    Every logged case — pre-op MRx, both nomograms' recommendations, what was programmed, and the post-op result. Once post-op is in, each eye is scored: whichever nomogram's recommendation sits closest to the treatment that would have landed on target "wins" that eye.

    717
    operated eyes
    88 / 99%
    myope sphere / cyl within one click*
    15
    nomogram signatures isolated

    Nomogram Signatures — the surgeon-specific adjustments that turn a manifest refraction into the programmed treatment. Each is graded by how strongly the evidence backs it.

    Strong · well-confirmed Moderate Our data only Diverges from convention Contradicted by our data Not yet testable here
    Applied & well-supported

    Presbyopia Sphere Hedge

    Strong
    In myopes, leave progressively less minus (toward slight plus) as age rises — a buffer against age-related overcorrection. Applied only above ~45 yr.
    Finding: corr(age, sphere-adjustment) = +0.41 in myopes; >50 yr averaged +0.17 D vs −0.27 D under 40.

    Hyperope Age-Neutrality

    Strong
    Do not apply the age hedge to hyperopes — treat sphere close to full regardless of age.
    Finding: corr(age, sphere-adjustment) = +0.08 in hyperopes (essentially none).

    Sphere −0.25 D Base Bias

    Strong
    A small baseline reduction of programmed sphere relative to the manifest value.
    Finding: median sphere adjustment −0.25 D across the dataset.

    Slight-Myopia Target

    Moderate
    Aim for a hair of residual myopia (~−0.1 D), not overcorrected plano.
    Finding: mean recorded target −0.10 D.

    Manifest-Refraction Ceiling

    Strong
    Don't over-tune sphere — the manifest refraction itself is the noise floor, so adjustments finer than ~0.25 D are not meaningful.
    Finding: ~0.2 D irreducible sphere scatter remains after modeling.
    Backed by our data — our practice, not the convention

    Cylinder Pullback Law

    Diverges
    Treat ~80% of measured cylinder, and a higher fraction of larger cylinders (≈77% in myopes, ≈85% in hyperopes).
    Finding: strong and consistent — corr(|cyl|, pullback) = +0.48; predicted to within one click 99% of the time. Conventional practice treats cylinder in full, so this pullback may under-correct astigmatism — the open question our post-op data must settle.

    Gentler-Than-Factory Sphere Slope

    Our data
    Sphere is adjusted less aggressively than the generic factory nomogram — about a −2% slope versus the typical −5%.
    Finding: myopic sphere slope −0.023 per D — a milder correction than the factory curve.

    Axis As Measured

    Our data
    Program the astigmatic axis exactly as refracted — no cyclotorsion or vector shift.
    Finding: mean axis change ≈ 0°. A cyclotorsion compensation (~6°) could in principle shave residual astigmatism — a refinement we do not currently apply.
    Beliefs our data does NOT support

    “Young → leave +0.50 hyperopic”

    Contradicted
    The common heuristic that young patients should be left slightly hyperopic.
    Finding: the opposite — young myopes receive more minus (fuller / slight over-correction), not left plus. Not present in these cases; would have to be imposed by rule.

    “Pull cylinder back more in hyperopes”

    Contradicted
    The intuition that hyperopes need a larger cylinder pullback than myopes.
    Finding: reversed — hyperopes are treated closer to full cyl (≈85%) than myopes (≈77%).

    “Higher myopia needs a bigger sphere adjustment”

    Not seen
    The intuition that greater myopia should get a larger correction.
    Finding: high myopes (<−4 D) received ~0 sphere adjustment vs −0.09 D for low myopes — if anything the reverse.
    Not yet testable in our data

    Steep-Cornea Retreatment Risk

    Untested
    Steeper preop corneas may carry higher retreatment risk → could warrant adjustment.
    Finding: keratometry present in only ~23 eyes — insufficient to test.

    Optical-Zone Overcorrection Interaction

    Untested
    Overcorrection may increase with both age and optical-zone diameter.
    Finding: age effect confirmed; the optical-zone interaction is not yet analysed.

    Cyclotorsion Axis Compensation

    Untested
    Shifting the treated axis by mean residual cyclotorsion (~6°) to reduce residual astigmatism.
    Finding: not applied — no cyclotorsion capture in the current data.

    Pachymetry & Preop-SE Predictors

    Untested
    Corneal thickness and preop spherical equivalent as inputs to refine the target.
    Finding: awaits post-op outcomes to fit against.

    These signatures update as post-op outcomes accumulate — divergent and untested items are the priority list for the Friday head-to-head.

    Combined-profile PTK calculator — Munnerlyn ablation depths for a two-pass (myopic + hyperopic) trans-epithelial plan, the summed depth profile, epithelium layer, net refractive effect, and RSB/PTA. Schematic decision-support only — verify against the laser's own profile, pachymetry and the OCT epithelial map before programming.

    Pass 1 — myopic (digs the trough)

    Pass 2 — hyperopic (mid-peripheral annulus)

    Epithelium (trans-epi — the variable)

    RK corneas thicken centrally to mask the flattening. Get the OCT epithelial map — this one number swings the result.

    Cornea

    * Sphere is a stated age policy (+0.50 ≤22 · +0.25 to 40 · plano after), aimed at residual sphere; its breakpoints were set to match this clinic's own programmed values on 51 logged eyes, not to post-op outcomes. Cylinder is a pullback fitted on 717 operated EX500 eyes. No post-op refraction has scored this nomogram yet — the prospective comparison against IBRA is still accruing. Decision support only — not a substitute for surgeon judgment, not medical advice. Internal Bimini AI tool.