Corneal degeneration & depos

ophthalmological sub

1. Corneal Degeneration & Deposition Clinical Approach Dr. Niwar Ameen Duhok Eye Hospital 2018

2. Contents Introduction Definitions Difference Corneal degenerations References

3. Introduction Degenerations of the ocular surface may result from physiologic changes associated with Aging process R elated to a specific disease F ollow chronic environmental insults to the eye, such as exposure to (UV) light . They may be unilateral or bilateral They uncommonly exhibit an inheritance pattern .

4. Definitions Degeneration refers to decomposition and deterioration of tissue elements and functions. D ystrophies are defined as bilateral, symmetric, inherited conditions that appear to have little or no relationship to environmental or systemic factors .

5. Difference Degeneratio n Opacity often peripherally located May be asymmetric Present later in life associated with aging Progression can be very slow or rapid Dystrophy Opacity often centrally located May be bilateral and symmetric Present early in life, hereditary Progression is usually slow

6. Degenerative Changes Age-Related (Involutional) Changes Normal involutional (age-related) changes that occur in the cornea include: G radual flattening along the vertical meridian resulting in against-the-rule astigmatic drift. M ild thinning of the central cornea. I ncrease in the refractive index with a corresponding decrease in transparency. The Descemet membrane thickens over time 3µm to 10µm at adult. G radual decrease in endothelial cell density that begins in the second decade of life from 4000 cells/mm²at birth to 2500-3000cells/mm². The cornea becomes more rigid with age, presumably due to increased crosslinking between collagen fibers within the corneal stroma

7. Epithelial and Subepithelial Degenerations

8. Coats white ring A small (1 mm or less in diameter) circle or oval-shaped area of discrete gray-white dots is sometimes seen in the superficial stroma. Referred to as Coats white ring, it represents iron-containing fibrotic remnants of a metallic foreign body. Once these lesions mature and are free of any associated inflammation, they do not change . T herapy with corticosteroids or other anti-inflammatory agents is not indicated.

9. Coats white ring

10. Spheroidal degeneration The condition has been reported under different names, including climatic droplet keratopathy, Bietti nodular dystrophy , and Labrador keratopathy . It is characterized by the appearance in the cornea, and sometimes in the conjunctiva, of translucent, golden brown, spheroidlike deposits in the subepithelium , Bowman layer, or superficial stroma P rimary SD , the deposits are bilateral and initially located in the nasal and temporal cornea. With age, they can extend onto the conjunctiva in the interpalpebral zone . It is not related to coexisting ocular disease. Secondary SD is associated with ocular injury or inflammation . The deposits aggregate near the area of corneal scarring or vascularization. Histology, extracellular, proteinaceous, hyaline deposits with characteristics of elastotic degeneration. The composition is not lipid, despite its "oil droplet" appearance . Rx; medical treatment is of no value, superficial keratectomy or phototherapeutic keratectomy ( PTK)for central cases. Recurrence after conjunctival resection is common.

11. Spheroidal degeneration

12. Iron deposition Most iron lines are related to abnormalities of tear pooling due to surface irregularities Often , they can be seen only by using red-free or cobalt blue illumination before instilling fluorescein . Iron lines and associations: Fleischer ring in early mild cases of Keratoconus. Hudson- Stahli line associated with keratorefractive surgery. Stocker line in pterygium confined to epithelium Ferry line in filtering bleb anteriorly, confined to epithelium Blood staining in some cases of hyphema

13. Hudson- S tahli line Stocker line

14. Calcific band keratopathy Calcific band keratopathy is a degeneration of the superficial cornea that involves mainly Bowman layer . The condition can be idiopathic, but the main known causes are: C hronic ocular disease such as uveitis in children, interstitial keratitis, severe superficial keratitis, and phthisis bulbi. H ypercalcemia caused by hyperparathyroidism, vitamin D toxicity, milk-alkali syndrome , sarcoidosis, or other systemic disorders. H ereditary transmission Renal failure, elevated serum phosphorus level with normal serum calcium. C hronic exposure to mercurial vapors or to mercurial preservatives. S ilicone oil instillation in an aphakic eye.

15. Calcific band keratopathy begins as fine, dustlike, basophilic deposits in the Bowman layer. These changes are usually first seen peripherally in the 3- and 9-o'clock positions. A lucid interval is seen between the limbus and the peripheral edge of the keratopathy . Eventually , the deposits may coalesce to form a horizontal band of dense calcific plaques across the interpalpebral zone of the cornea. A workup (eg, serum electrolytes and urinalysis) to rule out associated metabolic/renal disease should be considered . Underlying conditions, such as keratoconjunctivitis sicca or renal failure, should be treated or controlled. The calcium can usually be removed from Bowman layer by chelation with a neutral solution of disodium ethylenediaminetetraacetic acid (EDTA). The problem can recur but may not do so for years, at which time the treatment may be repeated. PTK using an excimer laser is not advised as a primary treatment.

16. moderate severe

17. Stromal Degenerations

18. Corneal Arcus It is most often an involutional change modified by genetic factors . The incidence is 60% in individuals between the ages of 50 and 60; it approaches 100% in individuals older than 80 years, men more women. While in younger than 40 years, the arcus is sometimes indicative of a hyperlipoproteinemia involving (LDL) with elevated serum cholesterol. It can be a prognostic factor for coronary artery disease in this age group . Arcus occurs occasionally as a congenital anomaly (arcus juvenilis), usually involving only a sector of the peripheral cornea not associated with abnormalities of serum lipid . Unilateral arcus is a rare condition associated with contralateral carotid artery disease or ocular hypotony . Arcus is also seen in Schnyder corneal dystrophy . Corneal arcus has no visual significance, and thus no necessary treatment.

19. Limbal girdle (of Vogt) It is a symmetrical yellowish-white band located parallel to the interpalpebral limbus. It is found more frequently on the nasal limbus than on the temporal. To be seen direct illumination, but is best seen with a combination of retroillumination and scleral scatter. Two forms of the white limbal girdle of Vogt have been described. Type I may be a variant of band keratopathy, featuring a ‘Swiss cheese’ hole pattern and a clear area separating the lesion from the scleral margin. Type II consists of small, white, flecklike, and needlelike deposits that are often seen at the nasal and temporal limbus in older patients. No clear interval separates this girdle from the limbus. Histologically , there is epithelial elastotic degeneration of collagen, sometimes with particles of calcium . This degeneration is an incidental finding and is asymptomatic, 60% aged 40 years. No treatment is required.

20. Slide Title Vogt of limbal Type II Type I

21. Crocodile Shagreen It is bilateral , symmetric corneal opacity that has a mosaic pattern resembling crocodile skin. Crocodile shagreen is most prominent in the central cornea, but may also be observed in the peripheral cornea . Both anterior and posterior forms have been described and appear clinically as polygonal gray opacities separated by thin lucent zones. Anterior shagreen is most often associated with trauma, hypotony, band keratopathy, X-linked megalocornea , and rigid contact lens wear in patients with keratoconus. Posterior shagreen is widely considered an age-related degenerative condition . DDx ; dystrophy of François . HPS; extracellular stromal vacuoles concentrated in the posterior stroma and just anterior to the Descemet membrane. The vacuoles often contain fibrillar -granular material . The opacity seen with anterior and posterior crocodile shagreen is visually insignificant and requires no treatment.

22. Cornea Farinata It is an asymptomatic, senile degenerative condition characterized by fine dustlike opacities located in the posterior stroma adjacent to the Descemet membrane. These opacities are best seen on retroillumination and are gray-brown to white, hence it has been described as having a “flour dust” appearance. These deposits occur bilaterally M ore prominent centrally D o not interfere with vision. The condition may be inherited in some patients . HPS; abnormal posterior keratocytes were found to contain membrane-bound intra-cytoplasmic vacuoles filled with lipid-like inclusions that may represent lipofuscin.

23. Cornea farinata

24. Senile Furrow Senile furrow degeneration is an appearance of peripheral thinning in the lucid interval of a corneal arcus that is seen in older persons. Although slight thinning is occasionally present , it is usually more apparent than real. The epithelium is intact. There is no inflammation , vascularization, or tendency to perforate. Vision is rarely affected. No treatment is required.

25. Senile furrow

26. Salzmann nodular degeneration It is a noninflammatory corneal degeneration. It occurs as a late sequela to old, long-term keratitis, or it may be idiopathic . Causes include phlyctenulosis, trachoma, and interstitial keratitis . The lesions may not appear until years after the active keratitis has subsided. It can be bilateral and is more common in middle-aged and older women. The nodules are gray-white or blue-white and elevated, and they may be associated with recurrent erosion . Histologic examination reveals localized replacement of Bowman layer with hyaline and fibrillar material. Treatment for mild cases is lubrication manual superficial keratectomy may be indicated in more severe These nodules may cause decreased vision secondary to irregular astigmatism). This degeneration may recur after removal.

27. Polymorphic amyloid degeneration It is a bilaterally symmetric, slowly progressive corneal degeneration that appears late in life . These deposits are usually axial, polymorphic, and filamentous. The opacities are gray to white and somewhat refractile but appear translucent in retroillumination. There is also an acquired (secondary localized) corneal amyloidosis, which may be associated with corneal inflammation (eg, trachoma, leprosy [Hansen disease], phlyctenulosis) or intraocular disease (eg, uveitis, retinopathy of prematurity) or may be secondary to trauma. Clinically, amyloid deposits in acquired corneal amyloidosis can appear as raised , yellow-pink nodular masses in the cornea or be nonspecific.

28. Polymorphic amyloid degeneration

29. Terrien marginal degeneration The cause is unknown. This condition is a quiet, essentially noninflammatory, unilateral or asymmetrically bilateral, slowly progressive thinning of the peripheral cornea. Prevalence is roughly equal between men and women. C ases usually occur in the second or third decade of life. The corneal thinning can be localized or involve extensive portions of the peripheral cornea . D egeneration begins superiorly, spreads circumferentially, and in rare cases involves the central cornea or inferior limbus . The epithelium remains intact, and a fine vascular pannus traverses the area of stromal thinning. A line of lipid deposits appears at the leading edge of the pannus

30. Spontaneous perforation is rare, although it can easily occur with minor trauma. Corneal topography reveals flattening of the peripheral thinned cornea, with steepening of the corneal surface approximately 90deg away from the midpoint of the thinned area. This pattern usually results in high against-the-rule or oblique astigmatism . Surgical correction is indicated when perforation is imminent due to progressive thinning or when marked astigmatism significantly limits vision . Crescent-shaped lamellar or full-thickness corneoscleral patch grafts may be used.

31. Terrien marginal degeneration

32. Lipid keratopathy In lipid keratopathy, yellow or cream-colored lipids containing cholesterol, neutral fats , and glycoproteins are deposited in the superficial or deeper cornea . P rolonged corneal inflammation with scarring and corneal vascularization (eg, herpes simplex or herpes zoster keratitis, trachoma ). Treatment is indicated in cases of compromised cosmetic appearance or decreased vision . Argon laser treatment with and without fluorescein Photodynamic therapy with verteporfin Subconjunctival and topical bevacizumab have been reported to reduce corneal neovascularization and lipid deposition . DDX; Schnyder corneal dystrophy.

33. Lipid Keratopathy

34. Endothelial Degenerations

35. Iridocorneal endothelial syndrome (ICE) syndrome is a spectrum of disorders characterized by varying degrees of iris changes, abnormal corneal endothelium, and peripheral anterior synechiae. The pathogenesis of ICE syndrome is unknown. Varying degrees of progressive endothelialization take place in the anterior chamber angle and on the iris surface . Three clinical variations of the syndrome have been described. Chandler variant of ICE syndrome, confined to the inner corneal surface, corneal edema may result from subnormal endothelial pump function. E ssential iris atrophy variant of ICE syndrome The Cogan-Reese variant shows multiple pigmented iris nodules. ICE syndrome becomes apparent most commonly in middle-aged females and is almost always unilateral . Penetrating keratoplasty and endothelial keratoplasty are treatment options for the corneal component of this syndrome.

36. ICE syndrome

37. Peripheral cornea guttae (Hassall-Henle bodies) are small, wartlike excrescences that appear in the peripheral portion of Descemet membrane . A normal aging change, they result from the thickening of Descemet membrane that happens throughout life; they occur on the posterior part of the membrane and protrude toward the anterior chamber . Rarely seen before age 20, they then increase steadily in number with age . When they appear in the central cornea, they are pathologic and are called cornea guttae .

38. Cornea verticillata Cornea verticillata refers to linear opacities located within the corneal epithelium that assume a characteristic whorl-like pattern. The opacities are located primarily in the inferior paracentral cornea and are not elevated. Their color may vary from white to brown. Cornea verticillata is seen in Fabry's disease and as a side effect from multiple systemic medications including amiodarone, chloroquine, chlorpromazine , indometacin , naproxen.

39. References External disease and Cornea, AAO, BCSC 22016-2017 Cornea, fundamental, diagnosis and management, Mark J. Mannis, Edward J. Holland, 4 th Edition, 2017 Kanski Clinical O phthalmology 8 th Edition, 2016

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