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The Value of Adding SD-OCT to Nonmydriatic Photography

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 , This prospective study, approved by the Cole , and age-related , 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 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 . 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 , 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%), 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 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 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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