Pediatric Ophthalmologists, some Optometrists and Vets tend to use Wood’s lamp more frequently than traditional slit lamps to detect epithelial damages, corneal ulcers and treat corneal ringworms in their patient’s eyes. But, is the Wood’s Lamp the safest option? Recent research seems to suggest otherwise.
What is a Wood’s Lamp? The Wood's lamp or Wood's light was developed over a 100 years ago, by the American physicist Robert Wood, in 1903. It is a source of long wave ultraviolet light of 365nm (commonly known as UV-A), that is used to detect corneal abrasions, corneal ulcers and foreign bodies, and to treat corneal ringworms. [1] The light, which usually appears as violet/light purple, cause the infected or damaged tissue to fluoresce.
What are the risks Associated with the Wood’s Lamp?
Eye Damage The Wood's lamp projects long wave ultraviolet light. For this reason, prolonged exposure to these rays, without protective goggles, has been seen to create eye problems. The longer one stares at those rays without protective goggles the more dramatic the damage to the eye.
Inaccurate Diagnostic A study published in the Emergency Medicine Journal in March 2019 found that eye examinations using a Wood's lamp fail to detect many common eye abnormalities. The study performed between December 2016 and July 2017, examined a sample of patients of 18 years old and older, who complained about eye-pain to the urgent clinic of an ophthalmology practice. An ophthalmologist then examined the patient's eyes with a Wood's lamp, and followed up by performing a slit lamp exam. The results gotten with Wood's lamp were compared with those gathered from the traditional slit lamp. Out of the 73 patients recruited, the overall sensitivity of the Wood's lamp was 52% (38/73; 95% CI 40% to 64%). [2] Based on the results of a traditional slit lamp examination, the “Wood's lamp only detected 9 of 16 corneal abrasions, 5 of 10 corneal ulcers, 5 of 9 corneal foreign bodies, 0 of 4 cases of non-herpetic keratitis, 1 of 2 cases of herpes keratitis, 1 of 5 rust rings and 18 of 28 other diagnoses.” [2]
What are some of the Better Product Alternatives to the Wood’s Lamp? While traditional slit lamp biomicroscopes are better suited to detect a range of eye issues, they are neither as portable and versatile, nor as cost effective as a Wood’s Lamp. Furthermore, traditional slit lamps generally use a polychromatic illumination source which might cause you to miss epithelial damages. Here are some safer, accurate and portable alternatives to Wood’s Lamp: 1. The Bluminator® ($80.00)
With its registered trademark, original design and competitive pricing it is difficult to find a better tool than the Eidolon Bluminator®.
The Bluminator® with its spectrally pure, blue beam of light is the optimal tool to perform a fluorescein examination of the anterior segment. The wavelength of its LED was carefully selected to provide the maximal fluorescence of damaged tissue. Its lens was specifically designed for the eye and has 28 diopter magnification. Eidolon Optical, recently developed a version of the product that attaches to your smartphone: the Photo-Bluminator II ($349.00).
2. Hand Held Slit Lamps ($595.00 - $5,000.00)
They enable you to perform a complete Slit Lamp Examinations and with the use of a Cobalt Blue Filter allow you to diagnose anterior segment infections, damages and corneal ulcers. Here is a list including some of the most popular ones:
The Kowa SL-17 ($4,195.00) weighs less than 800g and provides a choice of 10x and 16x magnifications, 3 slit widths* (0.1mm, 0.2mm, 0.8mm) plus spot illumination and a cobalt blue filter using a high illumination LED as the light source. It has a rheostat controlled light source from 0 to 20,000 Lux. The LED light source provides a much whiter light than ordinary halogen light sources found on competitive instruments.
The Eidolon 510L with a Cobalt blue filter ($645.00), the first hand held slit lamp designed was brought to market in 1997 for pediatric-ophthalmologists. It only weights 8oz and uses a bright halogen bulb. It can now be purchased with its smartphone adapter ($200.00) to perform a digital eye exam with your phone. It has a 20 diopter loupe and provides an adjustable slit length (2.5mm-20mm) for direct focal illumination and adjustable slit width (0.2mm - 0.6mm).
The Keeler Classic PSL ($5,000) Uses proven halogen illumination system. The illumination levels are controlled by a rheostat, to control the intensity of the illumination. It features fixation targets, and a 1mm square light patch for assessing anterior chamber flare.
The Heine HSL 150 ($1,295.00) has a bright xenon halogen illumination that is comparable in intensity with the best table-top slit lamps for examination of the anterior segment. It provides a 10x0.2mm up to 14x 4mm slit image for direct focal illumination with an optical section.
References:
Al Aboud DM, Gossman W. Woods Light (Woods Lamp) [Updated 2020 Aug 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537193/#
Hooker EA, Faulkner WJ, Kelly LD, Whitford RC. Prospective study of the sensitivity of the Wood’s lamp for common eye abnormalities. In: Emerg Med J. 2019. Available from: https://pubmed.ncbi.nlm.nih.gov/30630841/