Description

The 20D Large Lens is an essential tool for ophthalmologists, designed specifically for indirect binocular ophthalmoscopy. This specialized lens is crafted to provide a comprehensive examination of the retina, including critical areas such as the optic disc and macula. Its application is well-suited for routine diagnostic work in ophthalmology, offering practitioners a reliable means to conduct thorough retinal assessments.

Optical Features

• Dioptric Power: With a dioptric power of +20, this biconvex, double aspheric lens delivers precise optical performance.
• Field of View: It offers a field of view ranging from 46° to 60°, enabling wide retinal visualization.
• Image Magnification: The lens provides an image magnification of approximately 3.13x, facilitating detailed examination.
• Working Distance: A working distance of around 50 mm enhances usability during examinations.

Design and Material

The lens features aspheric glass optics complemented by colored aluminum or polycoat components, depending on the manufacturer. Its overall dimensions are approximately Ø56 x 20 mm, with a clear aperture of Ø47 mm. The design effectively corrects for field curvature, astigmatism, aberrations, and coma, ensuring high-quality imaging.

Cleaning and Sterilization

Proper maintenance is crucial for the longevity and performance of the 20D Large Lens. Recommended cleaning methods include:

• Cleaning: Use alcohol wipes for routine cleaning.
• Disinfection: Employ glutaraldehyde (2% or 3.4%) or a 10% bleach solution.
• Sterilization: Compatible with ethylene oxide gas and low-temperature systems like STERRAD.

Avoid steam autoclaving, boiling, or using solvents like acetone. Regular inspection for damage and appropriate storage in a clean, dry environment at room temperature are advised.

Customization and Accessories

The lens is available in a variety of color options, including Black, Blue, Gold, and more. Customization features such as engraving are offered, allowing up to 14 characters on the lens and 17 on the case. A single-lens case, which can also be engraved, is included.

Certifications

Where specified, the lens meets CE, FDA, and ISO13485 certifications, underscoring its compliance with industry standards.

Additional Considerations

While not typically used for slit lamp examinations, the 20D Large Lens remains a versatile and reusable tool in the ophthalmic field. Users should note that colored components may fade with repeated sterilization, and polycoat components may have a limited lifespan. The lens is available in versions suitable for autoclave sterilization or as a single-use option, depending on the manufacturer.