Content » Vol 101, January

Correspondence

How to Triple Pocket Dermatoscopy Device Magnification and Avoid Digital Interpolation

Calogero Pagliarello and Carlo Renè Girardelli

UO Multizonale Dermatologia, Ospedale ”Santa Chiara”, Largo Medaglie d’oro 9, IT-38122 Trento, Italy. E-mail: calogero.pagliarello@libero.it

Accepted Dec 14, 2020; Epub ahead of print Dec 15, 2020

Acta Derm Venereol 2021; 101: adv00360.

doi: 10.2340/00015555-3728

INTRODUCTION

Current hand-held dermoscopes provide 10× standard magnification. For greater magnification, dermatologists use adapters for smartphones and digital cameras, or, if portability is not essential, digital video dermoscopes. A smartphone or digital single-lens reflex camera coupled to a pocket dermoscope enlarges a specific portion of the image by cropping and resizing the image to fit the frame through interpolation. Image quality varies from manufacturer to manufacturer and, depends on the following: the sophistication of the algorithms; camera or smartphone sensor performance; and display quality, which in turn strongly influences clinical assessment (1).

Although a binocular stereoscopic contact dermoscope (Kocher Feinmechanik, Mössingen, Germany) and floor-stand stereomicroscopes provide binocular rather than monocular observation, different magnifications (× 6–80), and a remarkable optical performance, the former is bulky and no longer available, while the latter is expensive and requires a stable floor-stand. 

To triple pocket dermatoscopy device magnification and avoid digital interpolation we use a Zeiss monocular 3×12T* fixed onto the Heine Delta-20 dermatoscope eyepiece by means of a custom adaptor ring (Fig. 1) provided by Costruzioni Ottiche Meccaniche Lolli Adriano, (https://www.adrianololli.com) (an adapter for DermLite devices, which have a threaded eyepiece is also available).

The Zeiss monocular 3×12T* has an achromatic lens system, which gives sharp, colour-faithful images. Its shortcomings are the small 4-mm eye relief and a theoretical increased light loss and aberrations compared with a single instrument of equivalent power.

The authors have no conflicts of interest to declare.


Fig. 1. Zeiss monocular used as a magnification tripler fitted through custom adaptor ring onto the Heine Delta-20; Inset: Zeiss monocular 3x12T* and custom adaptor ring.

REFERENCES
1. Pagliarello C, Stanganelli I, Fabrizi G, Feliciani C, Di Nuzzo S. Digital dermoscopy monitoring: is it time to define a quality standard? Acta Derm Venereol 2017; 97: 864-865.
DOI: https://doi.org/10.2340/00015555-2663