Disorders of cornea: Ectatic Disorders, Corneal Dystrophy and Degeneration, Indication & Types of Corneal Transplantation

1. Disorders of the Cornea
Ectatic Disorders
Corneal Dystrophy and Degeneration
Indication & Types of Corneal Transplantation
Rabindra Adhikary
M. Optom 1st Batch [2019]
ravinems@iom.edu.np
Facilitator:
Dr. Leena Bajracharya
Presented on 20th June 2019 at Tilganga Institute of Ophthalmology

2. Corneal Ectatic Disorders
• Group of uncommon non-inflammatory
corneal disorders characterized by bilateral
central, paracentral, peripheral or generalized
thinning of cornea
– Keratoconus
– Keratoglobus
– Pellucid Marginal Degeneration
– Posterior Keratoconus

3. Keratoconus
• Progressive non-inflammatory central or
paracentral corneal stromal thinning
– Apical protrusion
– Irregular astigmatism
• Graded in 3 types according to corneal power
– Mild <48D
– Moderate: 48-54Ds
– Severe >54 Ds
• 50% of Normal fellow eyes will develop
keratoconus within 16 years

4. While KC has many systemic or ocular associations; it may
however present independently most of the times
• Systemic Association
– Down Syndrome
– Ehlers-Danlos Syndrome
– Marfan’s Syndrome
– Osteoggenesis Imperfecta
• Ocular Association
– VKC
– Blue Sclera
– Aniridia
– Retinitis Pigmentosa
– Leber’s Congenital Amaurosis
– Congential Cataract
– ROP

5. Symptoms
• Unilateral impairment of vision initially
• Unsatisfied with spectacle prescriptions
• Frequent changes in prescriptions
• Photophobia and watering in case of hydrops
• Sometimes bilateral presentation
– The condition of asymptomatic fellow eye with no
clinical signs of KC is called Forme Froste

6. Signs
• Charleux’ oil droplet sign
– on Direct Ophthalmoscopy at 50cm

8. • Fleischer’s Ring
– Hemisiderin pigment due to ferritin particles
deposition in basal epithelium

9. Munson’s Sign
• Conical corneal apex presses lower eyelid on
down gaze

11. Rizutti Sign
• Conical reflection in Nasal Cornea when light
is shone from temporal side

13. Scissoring Reflex on Retinoscopy
Early Sign

14. Vogt’s Striae
• Fine, vertical deep stromal stress lines
– Disappears on digital pressure

15. Acute Hydrops
• Descemet Membrane ruptureinflux of
aqueous into the stroma
– Pain, photophobia, blurring
– Tx: 5% NS + Cycloplegics or/and Bandage lens

16. Prominent corneal nerves

17. Anterior Stromal Scarring
• Healed hydrops after
6-10 weeksscar
Image: Cornea Atlas, 2nd Ed
J Krachmer
David Palay

18. Keratoscope
• Placido’s Disc image: Normal vs Keratoconus
– New version: computerized videokeratoscope
Irregular

19. Keratometry

20. • Inferior Corneal steepening on Topography
Early: symmetrical bow-tie pattern Late: Inferotemporally displaced cone

21. Categorization of KC a/c to
Morphological Patterns of Cone
Nipple Cone
Small, Paracentral, Steeper, Located
inferiorly or infero-nasally
Oval Cone
Inferiorly or infero-temporally
steeper cornea
Globus Cone
Overall steeper cornea involving
more than 3/4th cornea

22. Anterior Segment OCT
• Image1:Conical corneal apex
• Image2: Acute Hydrops

23. Etiology
• ENZYME Theory
– Increased epithelial lysoyme
– Decreased α-1 proteinase inhibitor in epithelium
– Decreased glucose-6 phosphate dehydrogenase
• Connective tissue abnormality theory
• Genetic theory- occasional association with
trisomy-21
• Hormonal Theory as it manifests in adult
• Rubbing theory: AD, VKC

24. ICRS

25. • Spectacle
– Early stages
 Contact Lenses
Soft Toric Lenses
Corneal GP Lenses
Special Keratoconus Designs (Rose K)
Piggy Back Lenses
Hybrid Lenses
Scleral Lenses

26. Collagen Cross-Linking -CXL
• Stabilize the ectasia
– The eye photosensitized with the riboflavin drops
are exposed to UVA
– Increase in 1-2 lines in Snellen’s acuity is expected
– Done only after progression is documented

27. Intra-corneal Ring Segments-ICRS
• Thin plastic semi-circular rings
– intrastromal
• Improve UCVA/BCVA
• Increase tolerance to Contact lenses in
advanced cases
• Needs correctional even after the impants
• Example: INTACS

28. Keratoplasty
• PK or DALK is severe disease
• DALK
– Contraindicated if H/O hydrops

29. Pellucid Marginal Degeneration
• Rare, progressive, bilateral peripheral corneal
thinning
– Presentation: adulthood
– 1-2 mm band of inferior corneal thinning
– 4-8 o’clock : 1 mm from the limbus
– Fleishcher’s ring and Vogt’s striae don’t occur
– Hydrops: very rare

31. Topography of PMD
• Kissing pigeon or butterfly pattern
– High astigmatism
– Diffuse steepening of the
inferior cornea
• Tx
– Specs/RGP/Scleral lenses
– Eccentric PK
– Thermocauterization
• Flattening with the heat at
the affected site
– ICRS
– Epikeratoplasty
– CXL

32. Keratoglobus
• Rare condition, bilateral involvement
– May be present at birth
– D/Dx:
• Congenital glaucoma
[buphthalmos]
• Megalocornea
– Globular protrusion
– Generalized thinning
– Trauma
• Susceptible to rupture
– Association:
• Connective tissue disorders
– Ehler-Danlos
– Marfan’s, etc
• Family / genetic

33. • Management of KG is challenging
– Due to generalized thinning
• Option of Keratoplasty is limited generalized
thinning of cornea
– Have to resort to scleral suturing high chances
of graft rejection
• Fragile cornea may rupture consider
protective eye wear
• Scleral lenses might be a boon

34. Ectatic disorders: comparison

35. Posterior Keratoconus
• abnormal posterior corneal curvature
– may be accompanied by overlying stromal
opacification.

36. Indications of Keratoplasty
• Optical
• Therapeutic
• Tectonic
• Cosmetic
While the aim of Keratoplasty is always guided by the primary
indication, many a time we can have overlapping of these
indications

37. Optical indication
• Primary purpose: improve vision
– Corneal scars due to trauma, ulcer, chemical injury
– Degenerations and dystrophies
– Keratoconus
– Keratoglobus
– Aphakic/Pseudophakic bullous keratopathy
– Congenital opacities
– Regraft secondary to rejection

38. Tectonic indication
• For the restoration of structural integrity of
the cornea
– Descematocele
– Corneal perforation
– Corneal stromal thinning

39. Therapeutic indication
• Option for failed medical treatment of
infective and/or inflammatory corneal disease
• Diseased tissue is removed
– Infective keratitis – fungal, bacterial or viral
– Corneal tumor that has not yet invaded the full
thickness

40. Cosmetic Indication
• Non seeing eye that is disturbing to the
patient due to the opaque white color
– might go for Keratoplasty for cosmetic
enhancement

41. Note that these contraindications simply mean the surgery is done
only when the primary condition is treated.

43. Lamellar
Keratoplasy
Anterior Lamellar
Superficial
[SALK]
Mid
[MALK]
Deep
[DALK]
Posterior lamellar
Deep Lamellar
Endothelial [DLEK]
Descemet
Stripping
Automated
Endothelium
DSAEK

44. Most Common in
Nepal
c>a>b>d>e

45. Corneal Degeneration
• Arcus Senilis/xerontoxon
– About 1 mm wide stromal lipid deposition
– Superiorly, inferiorly and then circumferentially

46. Significance of Arcus
• No visual disturbance
• When donor cornea has Arcus
–Recipient may be unsatisfied seeing the
white at the margins when the patient is
young
– Does not have effect on suturing or healing

47. Band Keratopathy
• Age related depositions of salts in the Bowman’s
layer, epithelial basement membrane and stroma
• Causes
– Heredity
– Metabolic: increased serum calcium and phosphorus
– Ocular: phthisis bulbi, chronic anterior uveitis, silicon
oil in AC, chronic edema or keratitis
– Age-related: sometimes may affect otherwise healthy
individuals with aging

48. Central chalky plaques with intermittent pores

49. Tx: Band Keratopathy
• Chelation
– Scrape the affected area with forceps and apply
1.5%-3% EDTA until all calcium comes off
• Keratoplasty is not warranted as visual
prognosis is not good.

50. Spheroidal Degeneration
• Amber colored granules
– Coalesce and spread
centrally
• Affected
– Adult men outdoors
• Precautions:
– Avoid UV rays
• Tx
– LK
– Superficial keratectomy

51. Common Corneal Dystrophies
Epithelial basement membrane dystrophy

52. Messmen Dystrophy

53. Cogan dot and microcysts

54. Reis Buckler’s Dystrophy

55. Lattice Dystrophy

56. Stromal Granular Dystrophy

57. granular

58. macular

59. Fuchs endothelial Dystrophy

60. Rama Rokka
Sameer Bhaila
Sandeep Kandel
Asmita Bhusal
Jeewa Bista Rabindra Adhikary
Birendra Mahat