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The Value of Adding SD-OCT to Nonmydriatic Fundus Photography Screening
The imaging technology can provide additive benefit to screening in the primary-care setting.
By Rishi P. Singh, MD
onmydriatic fundus photography has been 2 aims: to evaluate the feasibility of obtaining SD-OCT widely used as a screening tool in the primary- images in patients attending a screening visit in the care setting for the detection of ophthalmic primary care setting, and to determine whether adding diseases. Numerous studies have examined SD-OCT to nonmydriatic fundus image reading provided Nor validated the use of nonmydriatic fundus imaging additional diagnostic information. in screening for diseases such as diabetic retinopathy, This prospective study, approved by the Cole Eye glaucoma, and age-related macular degeneration, using Institute institutional review board, included 574 con- technologies ranging from Polaroid cameras in the 1990s secutive patients in an executive health program. The to digital imaging devices with automated image analysis 3D OCT-2000 (Topcon), which incorporates a high- in the current century.1-3 resolution fundus camera, was used to obtain both Recently, Tarabishy and colleagues4 at the Cole Eye SD-OCT and fundus images. Institute assessed the accuracy and sensitivity of single- SD-OCT images were obtained as cube sections field nonmydriatic digital fundus imaging, performed in a through the macula and the optic disk, and correspond- primary care setting and interpreted by an ophthalmolo- ing fast macular thickness maps and nerve fiber layer gist. In the study, both eyes of 1175 consecutive patients analyses were performed. Single 50° field fundus photos in an executive health program were imaged using a digi- were centered on the macula and optic nerve. Two tal nonmydriatic camera. The fundus images depicted a masked graders evaluated all images. They first interpret- single 45° field centered on the optic nerve and macular ed the fundus photographs and were then presented area. The investigators found that this screening modality with the corresponding SD-OCT data and asked wheth- was sensitive and accurate for the detection of patholo- er it confirmed, was noncontributory to, or refuted gies including macular degeneration, diabetic retinopa- their initial diagnosis. In addition, the 2 masked graders thy, and optic nerve cupping. reported cup-to-disc ratios, and these were compared to automated cup-to-disc ratios computed by the SD-OCT Adding SD-OCT device. Spectral-domain optical coherence tomography (SD-OCT) is an imaging technology that has been widely Results adopted in ophthalmology, but its efficacy as a screening Regarding the first aim of the study, to evaluate the tool for common ophthalmic diseases has not been fully feasibility of performing SD-OCT in a primary care set- explored to date. We performed a study5 to determine ting, adequate images were obtained in 568 of 574 whether adding SD-OCT improved the diagnostic capa- patients (98.9%) patients. Poor scans were attributed to bility of nonmydriatic fundus imaging. The study had patient movement or to lack of signal intensity due to
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A B
Figure 1. Fundus photograph and SD-OCT image. Fundus photograph appears essentially normal (A), but a prominent epireti- nal membrane is see on SD-OCT cube scan (B).
A B
Figure 2. Fundus photograph and SD-OCT image. Fundus photograph shows what appears to be geographic atrophy (A), and SD-OCT confirms the presence of outer retinal atrophy consistent with the diagnosis (B).
A B
Figure 3. Fundus photograph and SD-OCT image. Fundus photograph led to initial diagnosis of retinitis pigmentosa without cystoid edema (A); SD-OCT refuted the diagnosis, showing clearly that there is significant cystoid edema present (B). media opacity. In cases in which the nonmydriatic fun- fundus photograph appears essentially normal, but a dus image was deemed to be of poor quality, SD-OCT prominent epiretinal membrane is see on the SD-OCT could be performed and evaluated in 85.7%. cube scan. Of the total 568 patients evaluated, SD-OCT findings Regarding the second aim of the study, to determine were normal in both eyes in 516 (90.9%). Vitreomacular whether SD-OCT aided in diagnosis, the 2 masked grad- adhesion, vitreomacular traction, or abnormal foveal ers said that the SD-OCT images confirmed their initial contour was detected in 17 (2.9%), epiretinal mem- photo-based diagnosis in 86.7% of cases and refuted it in brane (ERM) in 20 (3.5%), drusen in 12 (2.1%), lamellar 13.3%. hole in 2 (0.3%), and cystoid macular edema in 1 (0.2%). Figure 2 shows an example of a patient with what Figure 1 shows an example of a patient in whom the appears to be geographic atrophy, and the SD-OCT con-
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firms the presence of outer retinal atrophy consistent with the diagnosis. Figure 3 shows an example of another patient for whom the SD-OCT refuted the initial diag- nosis of retinitis pigmentosa without cystoid edema; the SD-OCT shows clearly that there is significant cystoid edema present.
Conclusions The strengths of this study include its large sample size, its prospective design, and its use of masked grad- ers. The limitations include the use of a relatively healthy patient cohort, leading to low abnormal rates for both SD-OCT and fundus imaging. A recent study has validated that optical coherence tomography results in better detection of retinal pathol- ogy than standard nonmydriatic fundus photography.6 The use of SD-OCT in a primary care setting appears to be feasible, as we achieved a 98.9% rate of image acquisi- tion. SD-OCT, used as an adjunct to fundus photogra- phy, appears to have some added benefit, confirming the initial diagnosis in the large majority of cases. Overall, we concluded that SD-OCT does provide an additive benefit when evaluating patients in a nonmydriatic screening program. Studies of this combination of screening modalities in populations with a greater prevalence of ocular pathol- ogy would be helpful in further assessing its usefulness. Still to be answered is the question of whether the incre- mental gains in information gathered are worth the costs of the machine and additional acquisition time. n
Rishi P. Singh, MD, is a Staff Member in the Department of Ophthalmology at the Cleveland Clinic. Dr. Singh states that he has served as a consultant to and/or served on the speakers board for Bausch + Lomb, Genentech, Zeiss, Regeneron, and Thrombogenics, and that his institution has received grants from Alcon, Regeneron, and Genentech. He can be reached at [email protected].
1. Taylor R, Lovelock L, Tunbridge WM, et al. Comparison of non-mydriatic retinal photography with ophthalmos- copy in 2159 patients: mobile retinal camera study. BMJ. 1990;301(6763):1243-1247. 2. Lin DY, Blumenkranz MS, Brothers RJ, Grosvenor DM; The Digital Diabetic Screening Group. The sensitivity and specificity of single-field nonmydriatic monochromatic digital fundus photography with remote image interpreta- tion for diabetic retinopathy screening: a comparison with ophthalmoscopy and standardized mydriatic color photography. Am J Ophthalmol. 2002;134(2):204-213. 3. Hansen AB, Hartvig NV, Jensen MS, Borch-Johnsen K, Lund-Andersen H, Larsen M. Diabetic retinopathy screening using digital non-mydriatic fundus photography and automated image analysis. Acta Ophthalmol Scand. 2004;82(6):666-672. 4. Tarabishy AB, Campbell JP, Misra-Hebert A, Seballos RJ, Lang RS, Singh RP. Non-mydriatic single-field fundus photography for the screening of retinal diseases in an executive health clinic. Ophthalmic Surg Lasers Imaging. 2011;42(2):102-106. 5. Thomas AS, Seballos R, Lang R, Singh RP. Does spectral domain OCT provide any additional useful information to non-mydriatic fundus photography in the screening of asymptomatic patients? Paper presented at: Association for Research in Vision and Ophthalmology Annual Meeting; May 06, 2012; Seattle, WA. 6. Ouyang Y, Heussen FM, Keane PA, Sadda SR, Walsh AC. The retinal disease screening study: prospective compari- son of nonmydriatic fundus photography and optical coherence tomography for detection of retinal irregularities. Invest Ophthalmol Vis Sci. 2013;54(2):1460-1468.
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