Multicolor Scanning Laser Imaging in Diabetic Retinopathy Mohammad S. Z. Ahmad, MBBS and Zia Iqbal Carrim, FRCOphth SIGNIFICANCE: Diabetic retinopathy is a common cause of blindness in individuals younger than 60 years. Screening for retinopathy is undertaken using conventional color fundus photography and relies on the iden- tification of hemorrhages, vascular abnormalities, exudates, and cotton-wool spots. These can sometimes be difficult to identify. PURPOSE: Multicolor scanning laser imaging, a new imaging modality, may have a role in improving screening out- comes, as well as facilitating treatment decisions. METHODS: Observational case series comprising two patients with known diabetes who were referred for further examination after color fundus photography revealed abnormal findings. Multicolor scanning laser imaging was undertaken. Features of retinal disease from each modality were compared. RESULTS: Multicolor scanning laser imaging provides superior visualization of retinal anatomy and pathology, thereby facilitating risk stratification and treatment decisions. CONCLUSIONS: Multicolor scanning laser imaging is a novel imaging technique offering the potential for improv- ing the reliability of screening for diabetic retinopathy. Validation studies are warranted. Optom Vis Sci 2017;00:00–00. doi:10.1097/OPX.0000000000001128 Copyright © 2017 American Academy of Optometry Author Affiliations: Leeds Centre for Ophthalmology, St. James's University Hospital, Leeds, United Kingdom Corresponding Author: Zia Iqbal Carrim Leeds Centre for Ophthalmology St. James's University Hospital Leeds, LS9 7TF United Kingdom e-mail: zia.carrim@doctors.org.uk Diabetic retinopathy is one of the leading causes of sight loss in working-age individuals. 1 Early detection and regular monitoring of existing disease can help prevent loss of vision. Diabetic retinop- athy screening programs, such as in the United Kingdom, conven- tionally rely on color fundus photography. In the presence of media opacities, features of sight-threatening disease can sometimes be difficult to identify. 2 Multicolor scanning laser imaging is a new modality, based on confocal scanning ophthalmoscopy, which utilizes three wavelengths of laser to gather diagnostic information from different layers of the retina. 3 Composite images are derived from blue (488 nm), green (515 nm), and infrared (820 nm) laser reflections. The depth of penetration into retina is different for each wavelength. Blue laser, having the shortest wavelength, gathers information from the inner retina and vitreoretinal interface. Green laser penetrates further, is absorbed by hemoglobin, and provides better visuali- zation of retinal vasculature, as well as intraretinal exudation. Infrared laser penetrates the furthest and allows visualization of the outer retina and choroid, as well as changes in the retinal pigment epithelium. 4,5 It is postulated that multicolor scanning laser imaging can potentially identify pathology that is difficult to detect on corre- sponding color fundus photographs. 3,4 There are several reasons for this. Laser penetration through media opacities, such as cat- aract, is superior compared with visible light. 5 Confocal technol- ogy blocks scattered light from outside the focal plane so that images are sharp, offer higher resolution, and have high con- trast. 4,5 Use of live eye-tracking technology enhances image sta- bility and clarity. 5 This case series describes two patients who underwent color fundus photography as part of diabetic retinal screening. Abnormal features were identified, and referral was made. Multicolor scan- ning laser imaging was undertaken using a Heidelberg Spectralis device (Heidelberg Engineering, Heidelberg, Germany) prior to ex- amination by an ophthalmologist. Each case highlights a specific potential application of multicolor imaging. CASE 1 A 59-year-old man with a previous history of stroke and known diabetes had color fundus photographs of both eyes in September 2014 as part of his annual diabetic retinopathy screening. A pre- retinal hemorrhage was noted in his right eye (Fig. 1A), thereby prompting referral for further assessment. When he attended, multicolor scanning laser imaging was undertaken. This revealed obvious neovascularisation at the disc despite the presence of cataract (Fig. 1B). Urgent scatter laser treatment was undertaken. Two weeks later, complete regression of disc neovascularization was documented with multicolor scanning laser imaging (Fig. 1C). The reaction to scatter laser was still faint when observed directly but readily visible on the scanning laser image. CASE 2 A 42-year-old man with a 15-year history of diabetes and hyper- tension was noted to have beading and evidence of fibrosed vessels in the nasal quadrant of his right eye (Fig. 2A) at screening. He had clear media. No new vessels were seen in color fundus photographs of either eye. Multicolor scanning laser imaging was undertaken when he attended for review. This revealed intraretinal microvascular changes in detail, as well as an area of relatively featureless retina adjacent to fibrosed vessels (Fig. 2B). A suspicion of peripheral ischemia was confirmed with subsequent angiography (Fig. 2C). Early neovascularization was also identified. CLINICAL REPORT www.optvissci.com Optom Vis Sci 2017; Vol 00(00) 1 Copyright © American Academy of Optometry. Unauthorized reproduction of this article is prohibited.