Device Overview and Portability

The device is comparable in size and weight to a video camera, weighing approximately 980g (2.16 lbs) including the battery, facilitating easy portability. It can store data for up to 30 persons (60 eyes), with measurement data printable later. The docking station is compact (249mm W x 220mm D), allowing use on a refraction table.

Wireless Communication and Measurement Technology

Infrared wireless communication connects the main unit to the station printer, eliminating cumbersome cords. A newly developed three meridian phase difference measuring technique enables accurate and rapid measurements. Both centering (XY direction) and focusing (Z direction) are detected automatically, starting measurement when the eye is optimally positioned. Measurement frequency is optimized based on data reliability.

Display and User Interface

The device features a 2.5-inch color LCD for comfortable operation at a non-intrusive distance between physician and patient. The focusing indicator on the monitor shows Z-direction focusing. Right/Left eye detection is automatic to prevent accidental omission of measurements. Quick mode allows rapid measurement for children or patients who blink frequently. IOL mode is automatically selected for eyes with intraocular lenses post-cataract surgery to avoid errors.

Physical Features and Accessories

A built-in forehead rest stabilizes the instrument for easier alignment. Both right and left eye data are displayed in large, color-coded format on the screen. A 90° correction function adjusts the astigmatic axis when measuring patients lying down. The eye mask covers the unmeasured eye, helping patients naturally fixate on the target.

Battery and Power Management

The high-performance lithium-ion battery provides approximately 60 minutes of use per full charge, with a charging time of about 120 minutes. The battery can be recharged either by inserting it into the station or by connecting the measurement unit to the station with a power cord.

Measurement Capabilities and Modes

The device measures corneal curvature radius from 5.00 to 13.00 mm, with data displayed in 0.01 mm increments and corneal refractive power in 0.12 or 0.25 diopter increments. Measurement modes include R/K mode, AR/KM continuous measurement mode, and K mode, selectable via one-button operation.

Specifications Summary (AR-20 / ARK-30 Models)

• Refractive Power Measurement Range: -20.00D to +22.00D (vertex distance 12mm)
• Indication Steps: 0.12D or 0.25D
• Cylindrical Power Range: 0D to ±12.00D
• Minimum Pupil Diameter: ≥ 2.6 mm
• Corneal Curvature Radius: 5.00 mm to 13.00 mm
• Corneal Refractive Power Range: 25.96D to 67.50D (n=1.3375)
• Measurement Time: Approximately 0.2 seconds per measurement

Hardware and Connectivity

• 2.5-inch color LCD monitor
• Thermal line printer included
• RS-232C interface
• Power source: AC 100-120V ±10% / AC 200-240V ±10%, 50/60 Hz
• Station dimensions: 249(W) x 220(D) x 102(H) mm, 2.5 kg
• Station plus measuring unit dimensions: 284(W) x 220(D) x 216(H) mm, 3.5 kg

Accessories and Optional Equipment

• Standard accessories: spare fuses, spare printer paper, dust cover, power cord, battery, interface cable, hand strap
• Optional accessories: carrying case with portable stand, IC card system, neck strap, additional battery

Additional Features and System Integration

The device supports system upgrades and can be integrated with Nidek's auto optometric systems (AOS-2100/800/660) to enhance conventional optometric system functionality.

Manufacturer and Contact Information

Manufactured by Nidek Ltd., Japan, with international offices in the USA, France, and Italy. Contact details and URLs are provided for support and further information.

Summary

This ophthalmic diagnostic device offers portable, wireless, and automated measurement of corneal curvature and refractive power with high precision and user-friendly features. It supports multiple measurement modes, automatic eye detection, and quick operation modes for various patient needs. The compact design, integrated display, and battery system facilitate ease of use in clinical environments.