P.R.I.S.M. IQ

Intelligent surgical screening — facilitating surgeon judgment
Screening for LASIK / PRK / ICL / RLE
This is the Pre-Op Calculator ↗ Open Mono Planning ↗ Open Treatment Design ↗ Open Lens (IOL) ↗ Refractive Financials
Recommendation
OD Awaiting inputs
OS Awaiting inputs
Patient
Dominant Eye: not set

Right Eye

Dominant OD
I-S Ratio (iDesign)
Keratometry
Manifest Refraction awaiting refraction
Wearing Rx (glasses) opt ▸
Auto-Refraction opt▸
Manifest Refraction primary
Cycloplegic opt
iDesign (consensus) opt▸
Free-typed to 0.01 D — iDesign reads finer than standard 0.25 D refraction steps.
Ablation depth
—μm
Post-op K
—D
—
PRK 50 μm epithelium
LASIK 110 μm flap
Tissue altered PTA · ≤ 40%
—%
—
—%
—
Residual bed RSB · ≥ 300 μm
—μm
—
—μm
—
Ablation, PTA & residual bed are myopia-calibrated planning estimates (|max-meridian| × 16 μm); actual depth varies by laser platform and optical zone. Verify against your nomogram.

Left Eye

Dominant OS
I-S Ratio (iDesign)
Keratometry
Manifest Refraction awaiting refraction
Wearing Rx (glasses) opt ▸
Auto-Refraction opt▸
Manifest Refraction primary
Cycloplegic opt
iDesign (consensus) opt▸
Free-typed to 0.01 D — iDesign reads finer than standard 0.25 D refraction steps.
Ablation depth
—μm
Post-op K
—D
—
PRK 50 μm epithelium
LASIK 110 μm flap
Tissue altered PTA · ≤ 40%
—%
—
—%
—
Residual bed RSB · ≥ 300 μm
—μm
—
—μm
—
Ablation, PTA & residual bed are myopia-calibrated planning estimates (|max-meridian| × 16 μm); actual depth varies by laser platform and optical zone. Verify against your nomogram.

Disparity Between Eyes

OU Comparison
K Diff OU
—D
Axial Diff
—mm
Axial → Diopters
—D
Total Power Disparity
—D
Status
—
Corneal vs. Refractive Cylinder Threshold: > 1.00 D suggests accommodation / internal astigmatism — possible early touch-up risk
Right Eye · OD
Corneal Cyl—
Refractive Cyl—
Δ Disparity—
—
Left Eye · OS
Corneal Cyl—
Refractive Cyl—
Δ Disparity—
—
K-Axis vs. Refractive-Axis Threshold: > 15° between corneal cyl axis and refractive cyl axis suggests irregular astigmatism, lenticular contribution, or measurement error
Right Eye · OD
K Axis—
Refractive Axis—
Δ Disparity—
—
Left Eye · OS
K Axis—
Refractive Axis—
Δ Disparity—
—

Pentacam / Belin-Ambrósio Risk Screen

Weighted BAD-D reasoning · age + RSB modulated
Right Eye · OD
Awaiting tomography inputs
Left Eye · OS
Awaiting tomography inputs

Randleman Ectasia Risk Score

Validated ERSS · LASIK ectasia risk
All other factors (RSB, age, corneal thickness, MRSE) auto-populate from the calculator. RSB uses the LASIK residual bed. Topography pattern is the one factor requiring clinical judgment from your topographer.
Right Eye · OD
ERSS Total —
Awaiting inputs
Left Eye · OS
ERSS Total —
Awaiting inputs
Randleman JB, Trattler WB, Stulting RD. Validation of the Ectasia Risk Score System for preoperative LASIK screening. Am J Ophthalmol. 2008;145(5):813-818. Risk: 0–2 low · 3 moderate · ≥4 high. Screening aid only — not a substitute for surgeon judgment.

Dysfunctional Lens Syndrome Screen

▾
DLS Score — / 10
Awaiting inputs

ICL Eligibility Screen

SE ≤ −4.00 D · ACD ≥ 3.00 mm · AXL > 26 mm flag
Right Eye · OD
SE ≤ −4.00 D ——
ACD ≥ 3.00 mm ——
Axial Length > 26 mm ——
Awaiting inputs
Left Eye · OS
SE ≤ −4.00 D ——
ACD ≥ 3.00 mm ——
Axial Length > 26 mm ——
Awaiting inputs

Patient History & Risk Factors

Advisory · informs PRK/caution notes on recommendation
Flap-Risk / Lifestyle
Ocular Surface / Corneal History
Crystalline Lens Status (per eye)
Drives lens-based (RLE / cataract) routing. An eye heading for cataract surgery within a few years is poorly served by corneal reshaping first.

Refractive Procedure Recommendation

Metrics-driven · LASIK / PRK / ICL
Right Eye · OD
Awaiting metric inputs
Left Eye · OS
Awaiting metric inputs
⚕ Screening guide only. This calculator is a clinical decision-support and triage aid. It does not diagnose, prescribe, or determine candidacy. The final surgical decision rests entirely with the operating surgeon, integrating full clinical examination, patient history, and professional judgment. Estimates are planning figures and must be verified against your own measurements and nomograms.

Ectasia Risk Screening

  • Randleman JB, Trattler WB, Stulting RD. Validation of the Ectasia Risk Score System for preoperative LASIK screening. Am J Ophthalmol. 2008;145(5):813-818. — basis for the ERSS panel point values and risk tiers.
  • Ambrósio R, Belin MW, et al. Enhanced ectasia detection / BAD-D analyses (Belin/Ambrósio Enhanced Ectasia Display). — basis for the weighted BAD-D reasoning and the 1.6 suspicious / ~2.6 abnormal cutoffs.
  • Guerra F, Luz A, Price FW, Price MO, Schallhorn S, Belin MW. Role of age and residual stromal bed with BAD-D in ectasia susceptibility. — basis for the age + RSB modulation of the Pentacam verdict.
  • Belin MW. ABCD progression display; posterior elevation and pachymetric progression as early subclinical markers. — basis for the Db / Dp escalators.

Corneal Treatment Planning

  • Santhiago MR, et al. Percent tissue altered (PTA) and ectasia risk. — basis for the PTA thresholds (35% / 40%) used in LASIK vs PRK logic. Santhiago's analysis also found flap thickness carries more weight in PTA/ectasia risk than ablation depth — basis for the 100μm thin-flap rescue rule (v3.58). PRK PTA counts the ~50 μm epithelium removed (v3.60) so it is like-for-like with the LASIK figure, whose flap term includes its epithelium.
  • Thin-flap femtosecond LASIK (80–100μm) safety/efficacy studies — report no clinically relevant increase in intraoperative or postoperative complications vs. standard flap thickness, with femtosecond flap-thickness precision within ~10μm (vs. wide mechanical-microkeratome variability) — basis for treating a 100μm flap as a reliable, safety-equivalent alternative when it clears the standard-flap elevated-PTA/RSB zone.
  • Residual stromal bed convention: ≥300 µm minimum; max-meridian ablation (|steepest treated meridian| × ~16 µm) used for worst-case safety estimates.
  • Post-Op K floor conventions: <33 D hard ICL trigger; <34 D myopic; <35.50 D ICL favored to avoid over-flattening.

Dysfunctional Lens Syndrome

  • Waring GO IV, et al. Dysfunctional Lens Syndrome staging framework (Stage 1 presbyopia → Stage 3 early opacification). — basis for the DLS screen criteria and age thresholds.
  • HOA source guidance: iDesign total HO RMS at 6 mm pupil for lens-aberration signal; Pentacam measures corneal aberrations only.

Notes on Methodology

  • The composite BAD-D is the validated parameter; sub-index escalators and age/RSB modulation are a conservative, evidence-informed encoding — not a prospectively validated standalone algorithm.
  • Only D (composite) and Db (posterior elevation) can independently shift the LASIK/PRK verdict on an isolated finding — D is the regression-validated composite parameter, and posterior elevation has independent literature support as an early, specific sign. Df, Dp, Dt, and Da alone do not carry a published individual weighting, so an isolated finding on one of these is surfaced as a flagged item for surgeon review rather than changing the verdict; two or more elevated indices together (regardless of which ones) still escalate to Borderline.
  • Ablation, PTA, and residual-bed figures are myopia-calibrated planning estimates; actual values vary by laser platform and optical zone.
  • All thresholds are configured for screening sensitivity and should be reviewed against your practice's clinical experience and your medical director's guidance.
Patient Information
Notes / Auto-Ref & K's / Zones / Prep & Timeout
⚠️ Editing changes the evidence-based default thresholds. Only adjust if you intend to apply your own clinical criteria.