Services 3 — ESI, Inc.

Prager Shell® Immersion Biometry

Thomas C. Prager, PhD, MPH introduced the first Prager Shell® for ultrasound biometry in 1982 to improve the accuracy of axial length measurement. In December 2002, Dr. Prager joined with ESI, Inc. to develop an improved Prager Shell® and other ophthalmic products.

The Prager Shell® is currently being used in more than 4,000 ophthalmology clinics worldwide.

ESI manufactures twelve Prager Shell® models and assigned a specific model number. The A-scan equipment determines the correct Prager Shell® model needed for accurate immersion biometry.

Each Prager Shell® model is individually designed according to the A-scan manufacturers' recommended specifications for accurate and consistent probe placement. The proprietary and patented design automatically positions the ultrasound probe perpendicular, and at the correct distance from the eye, to insure an optimum scan.

The Prager Shell® has two internal guide rings that maintain probe perpendicularity. These guide rings are vented to provide proper fluid flow and eliminate air bubble formation in the shell lower chamber. The transducer probe can only be placed at a fixed depth in the Prager Shell®. This auto-stop feature places the probe tip at the correct distance from the corneal surface. (Model numbers designated with P100 do not include this feature and require the probe tip to be placed at the score line and secured with the set screw).

All Prager Shell® models have a Luer adapter located on the side of the instrument for quick and simple replacement of the used and contaminated Prager Shell® tubing Kit. The Prager Shell® Kits are available only from ESI, Inc.

Prager Shell® Advantages

Manufactured with precision tolerances.
Auto-stop feature positions the ultrasound probe the correct distance from the cornea for an optimum measurement.
Centering guides ensure the probe is perpendicular and correctly aligned in the shell, eliminating angle error.
Clear shell for the improved visualization of ocular shell placement and fluid level.
Integrated Luer connection for simple replacement of infusion Kit.
Low-cost, sterile single-use replacement Kits reduces the chance of patient cross-contamination. Kits are available with one way flow check-valve (KIT B) or without check-valve (KIT A).

Eliminates need for expensive ultrasound gel.
Simple one-handed immersion procedure.
Custom tray for Prager Shell® storage and soaking in aseptic solution.
Accuracy of Prager Shell® immersion biometry and optical biometry is clinically equivalent.
Immersion A-scan is not limited by media density.
Precise insertion and placement of the ultrasound probe in the shell.
Luer connector for easy replacement of used Prager tubing Kit.
Clear shell for improved visibility.
A specific model for each manufacturer's A-Scan biometer.