LOINC long common name : Deprecated PhenX measure - contact biometry;
LOINC description : Axial length of the eye and central corneal thickness is measured using contact biometry
and pachymetry. Depth of the anterior chamber, lens thickness and depth of the posterior
chamber can also be obtained. Many eye diseases are known to be associated with either
excessively short eyes (nanophthalmos and angle closure glaucoma) or excessively long
eyes (degenerative myopia, Stickler's Syndrome). In addition, ocular biometry provides
information about the thickness of the lens (for studies of cataract) and the size
of the posterior chamber. Axial length of the eye is an essential measurement for
selecting the proper intraocular lens when doing cataract surgery. Central corneal
thickness influences intraocular pressure measurements (thicker corneas result in
artificially higher pressure and thinner corneas in lower pressure). In addition thinner
central corneal thickness may be an independent risk factor for optic nerve degeneration
in glaucoma.Results of all measurements are then printed. The WG recommends that three
readings be taken and recorded from each eye for both axial length and central corneal
thickness (measurements in millimeters). The WG recommends that the central corneal
thickness-pachymetry measurements be taken first followed by the axial length measurements,
as presented in this protocol. This protocol for contact biometry uses the ultrasonic
A scan/pachymeter DGH 4000B SBH IOL Computation module. Other instruments can be used
to measure ocular biometry including axial length and central corneal thickness. If
other instruments are used, the reproducibility of the measurements should be comparable
to those acquired with this protocol. In addition, when other instruments are used
to collect these measurements, the manufacturer and model of equipment should be recorded.
These other devices may require some different steps than are described in this protocol.
Investigators should follow the equipment manufacturer's instructions to ensure quality
control.;
Has component