# Study of Diagnostic Accuracy: Fundus Photography vs. Optical Coherence Tomography
## 4 Discussion  
In Spain, the waiting list for outpatient consultations in the National Health System as of June 2023 is, on average, almost three months [35]. Based on a review of the literature on screening studies carried out in Spain, the coverage of diabetic retinopathy screening is 32.4% (95% CI: 30.8-34.0%) [36]. This level of coverage falls far short of the recommendation of the portfolio of standardized services, according to which all diabetic patients should have a biennial examination of the eye fundus. It is therefore vital for optometrists to be in a position to help in the screening of patients during the referral process, not only from the anterior pole but also from the posterior pole, with sufficient criteria to determine whether the patient can wait three months or must be referred via a faster route. In this study, for the first time, a direct comparison is made between FP and OCT in patients who were unaware of the health status of their posterior pole, thus avoiding bias on the part of the evaluators, or a timelier fixation on specific pathologies. It also provides a comparison of the assessments carried out by the optometrist using both instruments and those carried out by the ophthalmologist. In a 2021 study by [PERSON] [37], 3D OCT exhibited a good capacity to detect most of the characteristics of different alterations. It noted that OCT will be added to FP screening for chorioretian disorders in the future. The studies published to date focus on specific pathologies, such as [PERSON]'s quantitative comparison of drusen segmented on SD-OCT versus drusen delineated on color fundus photographs [38], or [PERSON]'s paper [39], which indicated that the combination of OCT with fundus photography can effectively identify disease. In a study of high levels of myopia, the sensitivity, specificity, PPV, and NPV of OCT combined with fundus photography were more than 94.0%, which were significantly higher than OCT or fundus photography alone (\(p<0.05\)). Our research verifies the validity of using OCT as an addition to FP by calculating diagnostic accuracy values when comparing the use of these tests (\(p\)-value: 0.01). The kappa coefficient also indicates that the proportion of better-than-chance agreement compared to the maximum possible agreement is higher when OCT is used in addition to FP. In an optometry clinic, retinal assessments based on FP and OCT are similar in terms of sensitivity; however, FP combined with OCT is more specific than FP alone. These results are similar to those reported by [PERSON] et al. [11], who evaluated the accuracy of glaucoma screening using FP combined with OCT and determined the agreement between ophthalmologists and ophthalmology residents. The diagnostic accuracy of the glaucoma screening significantly increased with the use of OCT. Ophthalmologists exhibited the same sensitivity (80%) as ophthalmology residents in glaucoma screenings. These improvements would enable optometrists to provide quality assessments with sufficient criteria to refer posterior pole abnormalities to an ophthalmologist as appropriate. This is of particular relevance in Spain, where optometrists do not diagnose but are responsible for detecting any abnormalities that should be referred to an ophthalmologist. Although the investment required to acquire OCT equipment is high, the prices are becoming more and more affordable. Optometrists are the first point of contact for pa who are trained to perform diagnoses of this magnitude [40]. A review of the bibliography shows that algorithms are being generated to identify retinal pathologies based on OCT images in data-limited situations, such as that described by [PERSON] et al. [41], who discuss the algorithms used for the detection of diabetic macular edema and dry age macular degeneration (AMD). In the future, artificial intelligence may speed up patient screening. In the meantime, however, a good assessment of the posterior pole by optometrists could include improved patient screening and earlier referrals to the ophthalmologist.