Description

The 20D Large Lens by Volk Optical is an essential tool for ophthalmic professionals, designed specifically for indirect ophthalmoscopy and comprehensive retinal examination. Renowned for its precision, this lens offers a well-balanced combination of magnification and field of view, making it ideal for both routine and specialized diagnostic procedures.

Key Features

• Dioptric Power: +20 diopters, providing substantial image magnification of approximately 3.13x.
• Field of View: Offers a wide viewing angle of 46°/60°, enabling thorough examination of the retina, including the mid-peripheral regions.
• Working Distance: Maintains an optimal distance of 47–50 mm from the cornea, ensuring ease of use and comfort.

Optical Design

Crafted with double aspheric glass optics, the 20D Large Lens minimizes common optical aberrations such as field curvature, astigmatism, and coma. This design enhances imaging quality, providing clear and detailed views of the retina. The lens also features advanced coatings on high-quality optical glass, contributing to its durability and performance.

Ergonomics and Handling

The ergonomic design of the lens ensures comfortable handling, allowing practitioners to conduct examinations with ease. Available in a variety of colors, including Black, Blue, Gold, and more, it offers personalization options to suit individual preferences.

Use Cases

This lens is particularly effective for:

• General diagnostic retinal examinations
• Estimation of optic disc size
• Visualization of the peripheral retina

While it excels in these areas, it is not typically used for slit lamp examinations, where other lenses like the 78D or 90D may be preferred.

Cleaning and Maintenance

Proper maintenance is crucial for the longevity and performance of the 20D Large Lens. Recommended cleaning involves using a mild, pH-neutral detergent and a soft cotton cloth. For disinfection, high-level disinfectants such as Cidex OPA or bleach solutions are advised, especially if the lens contacts the patient’s eye.

Sterilization

When necessary, sterilization can be performed using methods like Ethylene Oxide or Steam, with the use of a Volk sterilization case for protection. It is important to avoid certain substances like alcohol or acetone on contact elements and to refrain from using microfiber cloths.

Storage

After cleaning, the lens should be stored in a clean, dry environment at room temperature. Practitioners are advised to avoid using the lens if damaged and to be aware of potential discoloration of colored rings due to certain disinfectants.

Limitations

While the 20D Large Lens is a standard in ophthalmic diagnostics, users should note its limitations in detecting very early retinal changes, such as microaneurysms in diabetic retinopathy. Despite these limitations, it remains a valuable asset for comprehensive eye care, trusted by professionals worldwide.