The Lack of Concordance Between Subretinal Drusenoid Deposits and Large Choroidal Blood Vessels

PurposeTo evaluate the concordance between pseudodrusen as manifested by subretinal drusenoid deposits and large choroidal blood vessels using stereological analysis of spectral-domain optical coherence tomography (SD OCT) images.DesignRetrospective, observational case series.MethodsThe SD OCT images of 31 consecutive patients with the clinical appearance of pseudodrusen from a private-referral retinal clinic were retrospectively reviewed. A grid of 19 evenly spaced vertical lines was randomly superimposed on each SD OCT image using ImageJ to perform systematic uniform random sampling. The main outcome measure was the likelihood of association between subretinal drusenoid deposits and large choroidal vessels.ResultsUniform random systematic sampling of 589 samples found the proportion of geometric probes intersecting subretinal drusenoid deposits to be 0.28, large choroidal vessel 0.65, and both 0.19. This value was nearly identical to the product of the joint probabilities and was within the 95% confidence interval (0.15-0.21) of the point estimate as calculated by the binomial theorem, indicating mutual independence. The subretinal drusenoid deposits were associated with neither large choroidal vessels nor the intervals in between.ConclusionsOur results demonstrate that there is no concordance between subretinal drusenoid deposits and large choroidal vessels or the stroma in between. As a consequence, hypotheses postulating that subretinal drusenoid deposits are associated with large choroidal vessels or the choroidal stromal spaces should be abandoned. Stereological techniques are powerful methods used in image evaluation in other fields of study and appear to have utility in analyzing OCT findings of the retina and choroid.