![]() ![]() Retinal tears and detachment can occur in 50% of patients with an optic pit, as shown in Figure 10-79B that patient has an optic pit and a retinal tear involving the macula of the left eye. It is a small depression, located temporally in 75% of cases, in the optic nerve and is usually gray or yellow. Figure 10-78 shows myelinated nerve fibers in the peripheral retina.Īn optic pit is a congenital anomaly of the optic disc. Another dramatic example of myelinated nerve fibers at the disc is shown in Figure 10-77. Figure 10-76 shows the retina of a patient with myelinated nerve fibers. The condition is present at birth, does not change, and usually causes no visual impairment. The fibers appear as white patches with feathery borders that radiate from the optic disc and obscure the retinal vessels over which they pass. In this condition, the nerve fiber layer continues to myelinate into the retina beyond the lamina cribrosa. The benign condition myelinated, or medullated, nerve fibers is seen in 0.3% to 0.6% of all individuals. The examiner should check the cup-disc ratio in both eyes for symmetry. The normal ratio of the cup diameter to disc diameter varies from 0.1 to 0.5. The cup is the portion of the disc that is central, lighter in color, and penetrated by the retinal vessels. In the center of the normal optic disc, there is a funnel-shaped depression known as physiologic cupping. The relative pallor of the optic disc is caused by the reflection of light from the myelin sheaths of the optic nerve. The disc is pinkish in light-skinned individuals and yellowish-orange in darker-skinned individuals. The nasal border is normally slightly blurred. The disc should be round or slightly oval with the long axis usually vertical and with sharp borders. ![]() Its margins, color, and cup-disc ratio should be determined. The optic disc is the intraocular portion of the optic nerve and is seen with the ophthalmoscope. The most conspicuous landmark of the retina is the optic disc (Fig. The optic fundus must be assessed methodically, starting at the optic disc, tracing the retinal vessels emerging from it, inspecting the macula, and evaluating the rest of the retina. Finally, because the eye is an extension of the central nervous system, evaluation of the optic fundus can provide information about many neurologic disorders. In addition, the optic fundus is frequently involved with manifestations of systemic disease such as AIDS, infective endocarditis, hypertension, and diabetes a thorough evaluation of the fundus can provide valuable clues to their diagnosis. The optic fundus is the only area where the blood vessels can be seen in vivo it can provide an excellent picture of the state of the vasculature of other organs. But RAI’s “dovetail” JOIN technology processes all arms of the JOIN in parallel, operating more efficiently the more arms there are.Figure 10-74 Photograph of the retinas of the right (A) and left (B) eyes.Ĭareful assessment of the optic fundus is important for several reasons. ![]() Your relations on disk are dense with data.įully normalized data means many relations, and queries require large n-way JOINs that would kill a typical database. The relational model is known for being able to handle high row counts.Ĭloud storage enables open-ended scalability for your relational data.įully-normalized GNF data has no empty rows, no sparse data. Unlike other cloud database systems, this is truly a single copy of your data for multiple workloads. Applications can apply multiple logical data models to the underlying relations. Unlike more commonly used Third Normal Form, fully normalized Sixth Normal Form eliminates the need to reorganize data to suit each workload. RAI’s “dovetail” join unlocks the performance needed to make GNF practical. GNF extends Sixth Normal Form data modelling by adding concepts and meaning to the links that connect the individual Sixth Normal Form relations. In Sixth Normal Form, each relation has one or more key columns and just one value column. Graph Normal Form is RAI’s implementation of Sixth Normal Form, or 6NF, the ultimate expression of the relational model. RAI technology combines this flexibility and scalability to make building and querying enterprise-scale Knowledge Graphs a feasible reality for any organization. GNF is based on the relational model, well-known for its scalability, enabling you to load and process enterprise-scale data. RAI’s Graph Normal Form, or GNF, enables true re-use of your organization’s data assets for a data-centric architecture. ![]()
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