To the Editor:We have read the article by Lois et al,1Lois N. Cook J.A. Wang A. et al.Evaluation of a new model of care for people with complications of diabetic retinopathy: the EMERALD study. in which the authors have evaluated multimodal imaging (spectral domain OCT, 7-field Early Treatment Diabetic Retinopathy Study [ETDRS] fundus photography, and ultrawide-field scanning laser ophthalmoscopy [UWF-SLO]) for the detection of diabetic macular edema and proliferative diabetic retinopathy (PDR) in a study population of adult with type 1 or 2 diabetes with previously successfully treated diabetic macular edema or PDR. The study found that this new model of care for people with DR complications had an acceptable sensitivity compared with a standard ophthalmologists’ assessment, with the benefit of significant cost savings.For the detection of PDR, the sensitivity and specificity of UWF-SLO was higher than for 7-field ETDRS imaging (87% [95% confidence interval (CI), 79%–93%] and 49% [95% CI, 42%–56%] versus 80% [95% CI, 69%–88%] and 40% [95% CI, 34%–47%], respectively). In the study, the Optos system (Optos Inc) was used to obtain UWF-SLO images. The particular UWF-SLO device used in the study was not provided in the article nor in the previously published study protocol. One-third of retinal hemorrhages and/or microaneurysms, intraretinal microvascular abnormalities, and new vessels elsewhere might be situated outside the ETDRS fields, and visible in UWF-SLO but not in 7-field ETDRS photography.2Silva P.S. Cavallerano J.D. Sun J.K. et al.Peripheral lesions identified by mydriatic ultrawide field imaging: distribution and potential impact on diabetic retinopathy severity. Nevertheless, it was shown that UWF-SLO may underdiagnose PDR when compared with 7-field ETDRS imaging.3Silva P.S. Cavallerano J.D. Sun J.K. et al.Nonmydriatic ultrawide field retinal imaging compared with dilated standard 7-field 35-mm photography and retinal specialist examination for evaluation of diabetic retinopathy. During the UWF-SLO examination, a low-powered green (532 nm) and red (633 nm) laser simultaneously scan the retina and choroidal tissue; a composite picture is created by a digital combination of the 2 wavelengths. It was hypothesized that UWF-SLO images may have an inherent distortion and color variation owing to the required optics and scanning laser light source, and therefore worsen its performance in the detection of PDR.The rate of ungradable images within the study was 1% for spectral domain OCT, 6% for 7-field ETDRS images, and 5% for UWF-SLO images. We would like to ask whether the examinations were performed under mydriasis? If so, what topical agents were administered and was it done routinely or selectively based on the examiner’s discretion? Diabetes is regarded as a risk factor for presenting with a small pupil, and the pupillary dysfunction demonstrated in diabetes is related to autonomic neuropathy and primarily involves the sympathetic innervation of the iris dilator.4Grzybowski A. Kanclerz P. Methods for achieving adequate pupil size in cataract surgery. This sympathetic denervation is correlated with the duration of the disease and the development of systemic autonomic neuropathy. In DR screening programs, applying mydriasis not only significantly reduced the proportion of ungradable images, but also improved the accuracy of screening.5Gupta V. Bansal R. Gupta A. et al.Sensitivity and specificity of nonmydriatic digital imaging in screening diabetic retinopathy in Indian eyes. In contrast, even when using a short-acting mydriatic (tropicamide), pupil dilation can cause discomfort, especially for those who plan to return to work after the examination or need to drive a car to reach the screening facility.

Diabetes can also be associated with several clinical end points that are not detected by multimodal imaging, but have important implications for patient care. These factors include changes to intraocular pressure, neovascularization of the iris or angle, and cataract, to name a few. These are routinely and easily screened by ophthalmologists. Reliance on retinal imagery would invariably lead to decrease in their detection and treatment. One may wonder whether that would offset the relatively modest reduction in costs quoted by the authors (£13.9 per visit).

Exploring new methods for telemedicine, for artificial intelligence and automated DR detection algorithms, and for decreasing health care burden is relevant in these times, and the authors should be congratulated for their efforts. However, we feel it is far from clear whether this new model of care would also fit the routine screening for DR.

ReferencesLois N. Cook J.A. Wang A. et al.

Evaluation of a new model of care for people with complications of diabetic retinopathy: the EMERALD study.

Ophthalmology. 128: 561-573Silva P.S. Cavallerano J.D. Sun J.K. et al.

Peripheral lesions identified by mydriatic ultrawide field imaging: distribution and potential impact on diabetic retinopathy severity.

Ophthalmology. 120: 2587-2595Silva P.S. Cavallerano J.D. Sun J.K. et al.

Nonmydriatic ultrawide field retinal imaging compared with dilated standard 7-field 35-mm photography and retinal specialist examination for evaluation of diabetic retinopathy.

Am J Ophthalmol. 154: 549-559.e2Grzybowski A. Kanclerz P.

Methods for achieving adequate pupil size in cataract surgery.

Curr Opin Ophthalmol. 31: 33-42Gupta V. Bansal R. Gupta A. et al.

Sensitivity and specificity of nonmydriatic digital imaging in screening diabetic retinopathy in Indian eyes.

Indian J Ophthalmol. 62: 851-856Article InfoPublication History

Published online: June 25, 2021

Publication stageIn Press Journal Pre-ProofFootnotes

Disclosure(s): All authors have completed and submitted the ICMJE disclosures form.

The authors made the following disclosures: P.K.: Nonfinancial support – Visim and Optopol Technology.

R.T.: Personal fees – Alcon, Bayer, and Novartis, outside the submitted work.

Identification

DOI: https://doi.org/10.1016/j.ophtha.2021.05.013

Copyright

© 2021 by the American Academy of Ophthalmology

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