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Presentation on CORNEAL DYSTROPHY PPT.pptx
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- 2. Corneal dystrophies aregroup of heterogeneous slowly progressive, usually bilateral, mostly genetically determined, non-inflammatory opacifying disorders without any systemic and environmental associations.
- 5. •Most of thecorneal dystrophies begin in the early decades of life and progress gradually. The effect of these changes in some of the dystrophies may not be clinically apparent till the later years. •The underlying basis of all corneal dystrophies are genetic mutations some of which have been mapped, while others are yet to be identified. • Most of these mutations result in the transcription of aberrant proteins. These proteins are deposited in various corneal layers and give rise to the characteristic clinical features. • The pace of deposition also determines the natural history of the corneal dystrophy.
- 7. Drawbacks of olderclassification •Certain dystrophies extend beyond these strict anatomical demarcations like the Reis-Buckler Corneal Dystrophy, which initially affects the sub-epithelial area and Bowman’s layer and later the anterior and deep stroma •MCD affects both stroma and endothelium •Based on pathological and clinical features only
- 8. IC3D Classification ofthe Corneal Dystophies • Category 1: A well defined corneal dystrophy in which a gene has been mapped and identified and specific mutations are known. • • Category 2: A well-defined corneal dystrophy that has been mapped to one or more specific chromosomal loci, but the gene (or genes) remains to be identified. • • Category 3: A well-defined corneal dystrophy that has not yet been mapped to a chromosomal locus. • • Category 4: This category is reserved for suspected new (or previously documented) corneal dystrophies, although the evidence for such dystrophies being separate and distinct is not yet convincing.
- 9. Advantages of newerclassification • flexibility:As information accumulates, all true dystrophies should eventually reach category 1 • Or, some conditions that were once thought to be independent dystrophies may be later proven to be a variant of a different dystrophy. e.g Genetic and histopathological studies of central discoid corneal dystrophy have indicated that this condition is actually Schnyder corneal dystrophy. • The system also groups dystrophies together if they have a common genetic relationship • For example, there have been over 30 mutations in the transforming growth factor beta-induced gene (TGFBI) that have been found to cause types of lattice corneal dystrophy and granular corneal dystrophy
- 10. •Bowmans and descemetslayer were excluded •Reclassified CHED type 1 as PPMD •Included three types of ERED •Removed Grayson –wilbrandt CD •The current IC3D classification replaces the traditional classification system with a new system: epithelial and subepithelial dystrophies, •epithelial-stromal TGFBI dystrophies, • stromal dystrophies, and endothelial dystrophies
- 12. Epithelial basement membranedystrophy eponyms -Map-dot-fingerprint dystrophy Cogan microcystic epithelial dystrophy Anterior basement membrane dystrophy Inheritance- sporadic & rarely AD. Histology- thickening of basement membrane with deposition of fibrillary protein b/w basement membrane & bowman’s layer. Absence of hemidesmosomes of basal epithelial cells which is responsible for recurrent corneal erosions.
- 14. Onset 2nd decade 10%of pts develop recurrent corneal erosions in 3rd decade & others remain asymptomatic throughout life. Signs- Dot like opacities Epithelial microcysts Subepithelial map-like patterns surrounded by a faint haze Whorled fingerprint - like lines
- 16. •The geographic figuresin this disorder are caused by reduplications of basement membrane. • Similar geographic reduplications of basement membrane may be seen in the area of a healed epithelial defect; therefore, these changes may represent a response of the cornea to various insults •Recurrent corneal erosion (RCE) is a common complication of EBMD. If medical management of RCE fails, phototherapeutic keratectomy (PTK) or epithelial debridement and polishing of Bowman’s layer using a diamond burr have been proven effective treatments.
- 17. Epithelial recurrent erosiondystrophy (ERED) • Epithelial recurrent erosion dystrophy (ERED) is characterized by RCE that occurs spontaneously or after minimal trauma. • The attacks have been documented in patients as young as eight months, but usually appear around four to six years of age. • In most cases, the attacks decline in frequency and intensity by 50 years of age. • But in the Smolandiensis variant, half of patients develop progressive central subepithelial opacities as early as age seven. • In these cases, corneal erosions are treated medically, and a corneal graft is needed in about one-fourth of patients.
- 18. Juvenile hereditary epithelialdystrophy; Stocker- Holt variant Very rare, non-progressive abnormality of corneal epithelial metabolism, underlying which mutations in the gene encoding corneal epithelial keratins have been reported. Genetic Locus 12q13 (KRT3)and Gene -Keratin K3 Locus 17q12 (KRT12) Stocker–Holt variant Keratin K12 – Stocker-Holt variant
- 19. Onset and courseEarly childhood. Stationary or slowly progressive Multiple tiny intra-epithelial vesicles extend to the limbus and are more numerous in the interpalpebral area with clear surrounding epithelium. Whorled, wedged shaped opacities, cyst-like lesions or refractile linear opacities. In the Stocker-Holt variant the entire corneal is covered by fine grayish opacities that are fluorescein positive with fine linear lines in whorl pattern. It presents with more severe signs and symptoms Histology- irregular thickening of the epithelial basement membrane & intraepithelial cysts
- 21. Symptoms are variable.Pts may be asymptomatic or ocular irritation may begin in the first few mnths of life. Signs Myraid tiny intraepithelial cysts of uniform size but variable density are maximal centrally & extend towards but do not reach the limbus The cysts occasionally rupture onto the ocular surface and can cause pain and decreased vision due to scarring. Cornea may be slightly thinned & sensation reduced. - Treatment depends on severity, and can include lubricants, therapeutic contacts,
- 23. Previously thought tobe a variant of meesmann, now believed to be genetically distinct. Inheritance is AD or X- linked dominant with gene locus on Xp22.3 in the later in at least some patients. It is the only known corneal epithelial dystrophy with X-chromosomal dominant inheritance. Signs Grey bands with a whorled configuration Retroillumination shows densely packed
- 26. Treatment • Debridement ofthe corneal epithelium does not prevent the opacities from recurring, but rigid contact lenses have been shown to lessen the number of opacities in some patients
- 27. Rare disorder mainlyaffecting japanese patients Inheritance is AR with gene locus at 1q32 Tumor-associated calcium signal transducer 2 (TACSTD2) In this dystrophy, subepithelial gelatinous deposits composed of amyloid form on the surface of the cornea. The corneal surface develops a "mulberry" appearance. Symptoms of photophobia and decreased vision begin in the first two decades of life. The disorder recurs in corneal grafts.
- 29. • 4 types •band keratopathy • stromal opacity • kumquat-like • typical mulberry
- 30. Signs Grey subepithelialnodules Gradual confluence, stromal involvement & increase in size giving rise to a mulberry like appearance In advanced cases there is stromal opacities with large nodules and the cornea resembles the kumquat fruit (kumquat-lesions). Treatment is with repeated superficial keratectomy because of early recurrences on corneal grafts
- 31. • Contact lensescan help manage corneal surface irregularities. Superficial keratectomy (SK), LK, or PK have all been used in treatment, but the dystrophy often recurs within a few years. Limbal stem cell transplantation, along with PK or LK, has shown some success in preventing recurrence.
- 32. Epithelial stromal (TGFb1)dystrophies •Ries buckler • Thiel behnke • Lattice type1 • Granular type1 • Granular type2 • (All are category 1)
- 33. Reis- Bucklersdystrophy Inheritance is AD with gene locus on 5q31 (gene TGFB1) Histology shows replacement of Bowman layer & epithelial basement membrane with fibrous tissue which stains red with Masson trichome
- 35. Onset is in1st or 2nd decade with severe recurrent corneal erosions. Signs Grey-white, fine, round & polygonal subepithelial opacities , most dense centrally. Changes increase in density with age resulting in a reticular pattern due to the laying down of irregular bands of collagen replacing Bowman layer. these opacities extend into superficial then deep stroma and also to the limbus. In advance cases the opacities are denser and looks similar to curdled milk appearance . There may be clear spaces within the irregular opacities. course of RBCD is often more aggressive than
- 37. Corneal sensationis reduced & visual impairment may occur due to scarring at level of Bowman layer. Treatment is directed at recurrent erosions. Therapeutic contact lenses, medical management of RCE, SK, PK, and PTK have all been used in the treatment of RBCD, but recurrence rates are high. Mytomycin C may aid in preventing recurrence when used in conjunction with PTK in RBCD.
- 38. • Grayson-Wilbrandt CornealDystrophy (GWCD) is described as having variable patterns of opacification that extend anteriorly into the epithelium, as well as refractile bodies in the stroma. It is a good example of a category 4 dystrophy because there has only been one publication that describes only a single family with this condition, and the limited information we have on this condition does not rule out the possibility that it could be a variant of a better- described dystrophy, such as RBCD
- 39. Inheritance is ADwith gene locus on 10q24 & 5q31(geneTGFB1) Histology shows curly fibres in Bowman layer on electron microscopy Onset is at end of 1st decade with recurrent erosions
- 40. Signs : subepithelialopacities in a honeycomb morphology involving central cornea Treatment not required as visual impairment is less than Reiss- Bucklers dystrophy
- 44. This corneal dystrophyis often confused with Reis-Blucklers' dystrophy because it has a similar clinical appearance. Both dystrophies are autosomal dominant with recurrent erosions starting early in childhood. The visual impairment in Thiel-Behnke dystrophy begins much later in life than the visual impairment in Reis-Blucklers' dystrophy. Transmission electron microscopy differentiates these two dystrophies. In Reis- Blucklers' dystrophy rod-like bodies are seen in the region of Bowman's layer, and in Thiel-Behnke dystrophy "curly" fibers are seen in the region of Bowman's layer. Similar to Reis-Blucklers' dystrophy, Thiel-Behnke dystrophy is due to mutations in the beta-transfoming growth factor-induced gene human clone 3 (BigH3) located on chromosome 5, but the mutations occur with different amino acids at different sites within the gene.
- 45. • SCHNYDER CENTRALCRYSTALLINE DYSTROPHY Disorder of corneal lipid metabolism associated with raised serum cholesterol in approx 50% pts Inheritance is AD with gene locus at 1q36
- 47. Signs Central, oval,subepithelial crystalline opacity Diffuse corneal haze & prominent corneal arcus develop by 3rd decade Treatment by excimer laser Keratectomy
- 49. Lattice corneal dystrophytype 1 Aka biber haab dimmer CD Inheritance is AD with locus at 5q31 (gene TGFB1) Histology shows amyloid, staining with congo red & exhibiting characteristic green birefringence when viewed with a polarizing filter
- 51. Onset is atend of 1st decade with recurrent erosions which precede typical stromal changes, progressive with marked reduction in vision by 4th decade Signs Anterior stromal, glassy, refractile dots Coalescence into fine lattice lines, best seen on retroillumination Deep & outward spread sparing the periphery Initially the stroma between lines is clear but later ground glass apperance develops
- 53. Corneal sensationis reduced Treatment by penetrating or deep lamellar keratoplasty is frequently required. Recurrence in graft may occur.
- 55. Histology shows subepithelial& anterior stromal accumulation of amyloid Onset is within 1st & 2nd decades with severe photophobia, watering & visual impairement
- 56. LCD type 1vs type 2 • LCD1 is a more common corneal dystrophy found in a variety of Asian and European populations, where LCD2 is more rare and found mostly in people of Finnish decent. • The classic refractile lines or dots are seen in both disorders, but in LCD1, they generally are more prominent centrally and leave the peripheral 1mm of cornea spared, whereas in LCD2, they are more peripheral and less numerous. • Ocular signs and symptoms in LCD1 are generally notable within the first decade of life, while LCD2 generally becomes apparent after the age of 20. • In LCD1, recurrent erosions are common, and visual deterioration often requires corneal transplantation after the fourth decade of life. Recurrence generally occurs in grafts two to 14 years later. • Corneal transplantation is rarely indicated in LCD2; neurotrophic persistent epithelial defects after PK have been described. LK and PTK can also be used in the treatment of LCD1, but as with PK, the dystrophy eventually recurs.
- 57. Inheritance is ADwith gene locus at 5q31 Gene TGFB1 Histology shows amorphous hyaline deposits which stain bright red with masson trichrome Onset is in 1st decade but vision is usually not affected in early stage of disease Very slow progression GRANULAR DYSTROPHY CLASSIC type 1
- 59. Signs Small, white,sharply demarcated deposits resembling crumbs, sugar granules, rings or snowflakes in central anterior stroma Overall pattern of deposition is radial or disc shaped or may be in the form of a christmas tree Initially the stroma b/w the opacities is clear
- 60. Gradual increasein number & size of deposits with deeper & outward spread but not reaching the limbus Corneal sensation is impaired Treatment by penetrating or deep lamellar keratopasty is usually required by 5th decade. Superficial recurrences may require repeated excimer laser keratectomy
- 62. GRANULAR DYSTROPHY TYPE2 • Avellino dystrophy • Combined granular-lattice dystrophy • Autosomal dominant • Genetic locus 5q31 , TGFB1 • Onset -Early Childhood,Slowly progressive • Vision is affected only late when opacities affect the visual axis. Sometimes epithelial erosions occur
- 63. • Well definedwhite granular opacities like bread-crumb with star-shaped peripheries, central clear areas within the white opacities. There are lattice lines, which are short, dash- like, less refractile and do not intersect each other • Deposition of both hyaline and amyloid material in the corneal stroma that stain with Masson trichrome and Congo red
- 64. systemic inbornerror of keratin sulphate metabolism seems to have only corneal manifestations Divided in type 1, 1A & 2 depending on the presence or absence of antigenic keratan sulphate in the serum & cornea, these have been shown to be due to mutations in same sulphotransferase gene (CHST6)
- 65. Inheritance is ARwith gene locus at 16q22 Histology shows abnormally close packing at collagen in corneal lamellae & abnormal aggregations of GAG intra and extracellularly which stain with prussian blue & colloidal iron Onset is toward end of 1st decade with Profound visual impairment in late childhood and early adult life.
- 66. Signs Anterior stromalhaze involving central cornea Greyish- white, dense, focal, poorly delineated spots in anterior stroma centrally & posterior stroma in the periphery Superficial deposits may produce an irregularity of the corneal surface, although recurrent erosions are unusual
- 67. Increase insize & stromal haze Increasing opacification with eventual involvement of full-thickness stroma up to the limbus. The cornea is thin. Treatment by penetrating keratoplasty is successful but late recurrences on the graft may occur
- 69. Fuchs endothelial dystrophy Bilateral accelerated endothelial cell loss More common in women Associated with slight increased prevalence of open angle glaucoma
- 70. Inheritance AD althoughmajority are sporadic Onset slowly progressive disease is commonly in old age, although earlier onset can occur Signs Cornea guttata refers to irregular warts or excrescences of Descemet membrane secreted by abnormal endothelial cells
- 71. Specular reflectionshows tiny dark spots caused by disruption of regular endothelial mosaic Progression occurs to a beaten metal appearance In the natural course of the disease there is initially reduced or cloudy vision in the morning on waking up which is transient and clears within few hours. With progression there is delayed clearance and then there is no clearance. Persistent epithelial oedema results in the formation of microcysts & bullae (bullous keratopathy) which causes pain & discomfort on rupture, thought to be due to exposure of naked nerve endings
- 72. • Stage 1:Cornea guttate- center to involve the periphery • Stage 2: Corneal edema • Stage 3: Bullous keratopathy • Stage 4: subepithelial fibrosis, scarring and superficial vascularization in longstanding eyes
- 75. Specular or confocalmicroscopy: Polymegathism, pleomorphism, decreased hexagonality and reduced number of endothelial cells
- 76.
- 77. Treatment Topical sodiumchloride 5% drops or ointment, reduction in IOP Bandage contact lens Penetrating or deep lamellar keratoplasty Other options- conjunctival flaps & amniotic membrane transplants Cataract surgery may accelerate endothelial cell loss, a triple procedure (cataract surgery, lens implantation & keratoplasty) may be considered in eyes with corneal epithelial oedema .
- 78. posterior polymorphous corneal dystrophy(PPCD) • Most cases demonstrate autosomal-dominant inheritance, but isolated unilateral cases show no heredity, according to the IC3D. • Deep corneal lesions with nodular, vesicular or blister- like shapes are present, as well as linear lesions that resemble railroad tracks • Approximately 25% of patients show iridocorneal adhesions, and 15% have elevated intraocular pressure • Many times PPCD is fairly stationary; however, if patients do progress, treatment options are similar to those for FECD
- 88.