CorDeflVol

Compute corneal deflection volume (DeflVol) at the highest concavity (HC) moment using a two-sphere intersection model. The default algorithm is a closed-form analytical volume; an equivalent disk-integration method is also available.

Install

install.packages("pak")
pak::pak("GulumimiRen/CorDeflVol")

From the package directory:

install.packages(".", repos = NULL, type = "source")

Install from release tarball

Download CorDeflVol_0.1.0.tar.gz from the v0.1.0 release (Assets on that page).

With pak (local path or release URL):

pak::pak("path/to/CorDeflVol_0.1.0.tar.gz")

pak::pak("https://github.com/GulumimiRen/CorDeflVol/releases/download/v0.1.0/CorDeflVol_0.1.0.tar.gz")

With base R:

install.packages("path/to/CorDeflVol_0.1.0.tar.gz", repos = NULL, type = "source")

Usage

library(CorDeflVol)

CR <- 7.8
IR <- 6.4
DeflAmp <- 0.93

# scalar
deflvol(CR, IR, DeflAmp)

# vectorized
deflvol(c(7.8, 7.5), c(6.4, 6.2), c(0.93, 0.90))

# column-wise with dplyr
library(dplyr)
df <- df |> mutate(DeflVol = deflvol(CR, IR, DeflAmp))

# disk integration (optional)
deflvol(CR, IR, DeflAmp, method = "integral", N = 4000L)

Inputs

Parameter	Description	Unit
CR	Corneal curvature radius	mm
IR	Inverse curvature radius	mm
DeflAmp	Deflection amplitude at HC	mm

Units must be consistent across all three inputs (mm).

Missing or non-positive radii return NA; non-overlapping geometry returns 0.

Outputs

Parameter	Description	Unit
DeflVol	HC deflection volume	μL

When inputs are in mm, DeflVol is in μL (1 mm³ = 1 μL).

Geometry

Sphere-center distance: d = CR + IR - DeflAmp.

Closed-form two-sphere intersection volume:

DeflVol = π (CR + IR − d)² [d² + 2d(CR + IR) − 3(CR − IR)²] / (12d)

The integral method computes the same volume by trapezoidal disk integration over the overlap region (default N = 4000 segments).

Citation

If you use CorDeflVol in your research, please cite the article describing the DeflVol model:

Ren Q, Deng Z, Chu Z, Pan Z and Wan P (2026). DeflVol: a model-derived volumetric descriptor of corneal deflection at highest concavity under Corvis ST air-puff loading. Frontiers in Bioengineering and Biotechnology, 14:1933733. https://doi.org/10.3389/fbioe.2026.1933733

License

MIT — see LICENSE.