readFile {rPACI}

Read a corneal topography file in any available format (recommended by default)

Description

This function is a general wrapper function, able to read corneal topography files in any format supported by rPACI. Internally, it analyzes the file and detects its format, and then it uses the appropriate specific reading function (by now, two are available: readCSO and readrPACI). This is the reading function recommended by default, as it is able to read any supported file format.

Usage

readFile(filepath, ...)

Arguments

filepath

A file path to a corneal topography file in any supported format.

...

Optional arguments of any of the reading functions.

Details

A corneal topographer is an ophthalmic clinical device that obtains measurements in the cornea (the anterior part of the eye). A Placido disk corneal topographer makes use of the Placido disk (see references and the vignette linked below), which produce a circular pattern of measurement nodes.

This function internally determines the format of the specified file and then applies either readCSO or readrPACI if possible, or else it throws an error (if none can be applied, when the file format does not fit any of these two available formats). All this process is transparent to the user, so that using readFile with one file type or another is done in the same way, and it produces the same results. The readFile function propagates its input parameters. See those functions' documentation for more information about their arguments.

This function produces a data.frame in the usual format used by rPACI, i.e., a list with three columns (x and y coordinates of each point, and its ring index) and a row per data point, according to the function parameters (by default, 24*256 = 6144 rows or data points).

See more details about corneal topographers and the file structure in vignette("topographersDataFormat", package = "rPACI").

Value

A data.frame containing the corneal topography points, with columns:

x		The X Cartesian coordinates of the points
y		The Y Cartesian coordinates of the points
ring index		Number or index of the ring to which each point belongs

The resulting data.frame may also include in its Parameters attribute (attr(result,'Parameters')) the list of parameters used for the simulation (only if it was generated with simulateData and saved with writerPACI).

References

Rowsey, J. James, A. E. Reynolds, and Randy Brown. 1981. "Corneal Topography: Corneascope." Archives of Ophthalmology 99 (6): 1093-1100. doi: 10.1001/archopht.1981.03930011093022.

Pinero, D. P. 2015. "Technologies for Anatomical and Geometric Characterization of the Corneal Structure and Anterior Segment: A Review." Seminars in Ophthalmology 30 (3): 161-70. doi: 10.3109/08820538.2013.835844.

Samapunphong, Sopit, and Dimitri Azar. 1998. "Placido and Elevation-Based Corneal Topography. A Review." Ophthalmology Clinics of North America 11 (3): 311-29. doi: 10.1016/S0896-1549(05)70059-6.

Examples

# Read the example file "N01.txt" (the file is in the CSO file format)
dataset1 = readFile(system.file("extdata","N01.txt", package="rPACI"))

dataset2 = readFile(system.file("extdata","ds2.txt", package="rPACI"))