Ophthalmoscopic Signs of Retinal Disease

1. Ophthalmoscopic Signs of Retinal Disease Optometry 8370 Winter 2008

2. “The universe is made of stories, not atoms.” Muriel Rukeyser American poet

3. The art of eye care… • Making the the correct diagnosis (really thinking about the case) • Taking care that the patient is managed appropriately • Insuring that the patient feels like they’ve been taken care of • Eyes don’t exist in a vacuum; there is a person attached

4. Disease • “An alteration of the state of the body which interrupts of disturbs the performance of the vital functions” • Dictionary of Visual Science, 3rd ed.

5. Dystrophy • “1. Faulty or defective nutrition. 2. Abnormal or defective development. 3. Degeneration.” • Dictionary of Visual Science, 3rd ed.

6. Experience… • “Difference between the need to describe and the ability to make a diagnosis.” • Duane’s Ophthalmology

7. When in doubt about what we see with ophthalmoscopy… … we may be able to provide a diagnosis, or at least generate a list of probable diagnoses (differential diagnosis) if we place our observations in context of other observations.

8. Pathologic correlates to ophthalmoscopy should be learned for 2 reasons: • 1. Unfamiliar lesions may be described clinically. Understanding why lesions appear the way they do can show us the way from clinical information to likely pathology, and thereby lead to a diagnosis…

9. Pathologic correlates to ophthalmoscopy should be learned for 2 reasons (cont): • 2. Knowing why a lesion appears the way it does may lead to an explanation of its origin (pathogenesis)

10. Normal fundus: • Color related to amount of pigmentation of RPE and choroid, together with the blood flow through the choroid • With the exception of the macula (where xanthophyll pigment may add a yellow color), normal neurosensory retina is transparent • Loss of retinal transparency or acquisition of color by neurosensory retinal tissue indicates pathology…

12. Normal fundus… • Reflection from the surface of the retina during ophthalmoscopy indicates a healthy ILM and a true basement membrane secreted by the Muller cells • Normal retinal blood vessel color depends on the state of the blood flowing through them, since the wall of a normal vessel is transparent. (Therefore, the effects of arteriosclerosis (thickened vessel walls) are superimposed on the appearance of the blood column)

13. Normal macula: • Ganglion cell and NFL layers are pushed aside in the fovea • OPL (connection of rods & cones to the bipolar layer) is oriented obliquely • Cystlike spaces may occur at the OPL of the macula (Henle’s layer) due to fluid accumulation or swelling of Muller cells, leading to the formation of spaces

15. Normal macula… • 5 mm in diameter • Fovea: 1.5 mm in diameter, same as average optic disc; represents a depression of the inner retinal surface in the center of the macula • Foveola: 0.35 mm in diameter; central floor of fovea; only cones and their nuclei • Umbo: tiny depression in center of foveola (responsible for FLR)

16. Normal macula… • FAZ: resides inside the fovea, outside the foveola • RPE: At fovea, taller, thinner, contain more and larger melanocytes than other areas of retina; actively pump water and ions out of the subretinal space

17. Normal macula… • Remember the other retinal blood/brain barrier: the tight junctions of retinal capillary endothelial cells (across which free fluorescein also cannot pass) • Bruch’s membrane functions with the RPE (the other retinal blood/brain barrier) to provide a barrier and supportive system to the overlying retina…

19. Normal macula… Bruchs membrane consists of 5 layers: • Basal lamina RPE • Inner collageneous layer • Elastic fiber layer (relatively thicker) • Outer collagenous layer • Basal lamina of outer choriocapillaris

21. 5 Retinal Color Changes… …indicate pathology in ophthalmoscopic examination: • White • Gray • Yellow • Black • Red

22. Retinal Color Changes… • Location of color change may determine the shape of the lesion e.g. NFL heme will appear bright red and have feathery borders; sub-RPE heme will appear brown-black and have sharp borders

23. Retinal Color Changes… • Identification of retinal vessel embolic material depends on color: • White: calcific, likely originating from a calcified heart valve or calcified atheromatous plaque • Yellow: likely originated from a noncalcified atheromatous plaque (retinal artery embolus is termed a Hollenhorst plaque) • Gray-white: likely originate from platelet emboli

24. White Fundus Changes… • Fibrous connective tissue (scleral crescent, healed scar from disciform ARM, proliferative diabetic membranes, silver-wire vessels due to arteriosclerosis) • Gliosis… similar to fibrosis as mechanism for repair of neurosensory retina (contributes to white disc in optic atrophy, preretinal membrane, “snowbank” in pars planitis)

28. White Fundus Changes… • Necrotic retina (viral, fungal, protozoal) • Cotton-wool spots (focal retinal infarct at NFL which induces transection of axons; restricted to posterior pole) • Inflammatory cells (retinal vessel sheathing, white-centered hemes (Roth spots), granulomatous deposits (yellow to yellow-white)) • Drusen (usually yellow-white, more white when calcified)

31. Arteritic optic neuritis

32. Lipofuscin accumulation in RPE cell

33. RPE displacement over drusen

34. Gray-White Fundus Changes: • Retinal edema (e.g. leaky vessels in diabetic retinopathy, trauma) • Storage diseases (e.g. accumulation of storage material in ganglion cell layer in Tay-Sachs) • Early necrosis

35. Branch artery occlusion

36. Yellow Fundus Changes: • Primarily due to lipid deposition (from exudation or accumulation of degenerated cells) • Exudation: Occurs when there is damage to a vessel, allowing nonselective escape of plasma components such as higher molecular weight proteins and lipoproteins; should be linked ophthalmoscopically to a specific vascular pathology

38. Yellow Fundus Changes… • Exudates: • May appear more white over time, as lipid content diminishes due to vascular resorption and phagocytosis • Tend to occur in the OPL, shaped like cylinders in 3D, resulting in a round shape with distinct edges when viewed from above • Macular star: oblique orientation of OPL allows view of cylinders in profile rather than cross section • Ring-shaped exudates have source inside of ring

41. Black Fundus Changes: • Black appearance usually due to response of RPE tissue to change or injury: gain of melanin by enlargement of RPE cells (hypertrophy) or by replication (hyperplasia) • Slate-gray or brown-black lesions of fundus usually due to lesions of choroidal melanocytes (congenital melanosis oculi, choridal nevi and melanoma)

42. Black Fundus Changes… • Remember: RPE cells may also be lost due to tissue change (as over drusen, revealing the basement membrane accumulation, or in a window defect), or the tissue may change to a different type of adult cells, e.g. fibrous tissue or bone (metaplasia)

43. Black Fundus Changes… • Remember: Increased pigmentation is commonly associated with an increase in RPE cell size, as seen in the normal macula, where RPE is taller and more pigmented than in other parts of the normal retina

44. Black Fundus Changes… • Congenital hypertrophy of RPE (focal jet-black appearance which may not be uniform, distinct and possibly scalloped borders, often in groups of lesions (“bear tracks”), likely present from birth ) • Injury-induced hypertrophy (tight adhesions may be formed between RPE and sensory retina, as in RD demarcation line, CR scars (toxo), laser burns; frequently accompanied by basement membrane deposits, and collagen deposits (metaplasia), with resulting mild elevation)

47. Black Fundus Changes… • RPE melanin may accumulate in the retina, especially around vessels; since vessels frequently branch, may have “bone-corpuscular appearance” (Primary RP, blunt trauma, intraocular inflammation (e.g. late syphilis))

48. Intra-retinal RPE

49. Red Fundus Changes: • Indicates blood in an abnormal location • May be intravascular (implying vascular pathology, e.g. in DR, microaneurysms (difficult to see with ophthalmoscope), neovascularization (between ILM and hyaloid face)) • May be extravascular (heme)

50. Red Fundus Changes… • Location of heme effects color (red-black in a fresh heme between RPE and Bruch’s, bright red in a fresh heme in front of RPE) • Location of heme accounts for shape • Boat heme: Between NFL and ILM • Flame heme: within NFL • Dot or blot heme: within deeper layers (outermost) retina