This document summarizes various congenital corneal abnormalities including microcornea, megalocornea, and cornea plana. It then discusses corneal ectasias like keratoconus, keratoglobus, and pellucid marginal degeneration. Keratoconus is characterized by thinning and distortion of the cornea and can be detected using tools like retinoscopy, slit lamp examination, and corneal topography. It progresses slowly from puberty to middle age. Treatments include spectacles, rigid gas permeable contact lenses, and keratoplasty. Keratoglobus involves generalized corneal thinning from birth. Pellucid marginal degeneration causes inferior corneal thinning in a crescent shape.

1. Corneal Disease
Lecturer:
Miss.Yumna Tariq
M.Phil. Scholar ( Optom)

2. Congenital abnormalities of
cornea
1. Microcornea:
• a congenital condition
• the corneal diameter is <10 mm (or <9 mm in
newborns).
• Unilater or bilateral
• It is believed to arise due to arrest of growth of the
cornea in the 5th gestational month.
• Hypermetropic

4. 2.Megalocornea:
• Large corneal diameter > 13mm
• Bilateral
• Usually X-linked
• 90% of the affected individuals are Males
• High Myopia and Astigmatism

5. Megalocornea

6. c. Cornea Plana:
Severe decrease in corneal curvature
resulting in reduced refractive power of the
cornea ( 20D – 30D)
• Rare
• Bilateral
• Hypermetropia

7. Normal cornea vs cornea plana

8. Corneal ectasias:
Ectasia:
• an enlargement, dilation, or ballooning effect

9. Corneal ectasia?
• are a group of uncommon, noninflammatory, eye
disorders characterised by
• bilateral thinning of the central, paracentral, or
peripheral cornea
• Most common
1. Keratoconus
2. Keratoglubous
3. Pellucid marginal degeneration

10. 1.Keratoconus:

11. • a progressive, non- inflammatory,
• bilateral, asymmetric disease
• characterized by paraxial stromal thinning and weakening
that leads to corneal surface distortion.
• Onset = around puberty, slow progression thereafter until
the 3rd & 4th decades of life
• Role of heredity?
• Most pts. do not have positive family Hx.

12. Presentation:
1. Reduce visual Acuity
2. Frequent changes in spectacle prescription
3. Glare
4. Ghost images
5. Monocular Diplopia

13. Signs:
1. Progressive myopia and irregular astigmatism
2. Rizzuti sign -------> conical reflection on the nasal cornea when
a penlight is shone from the temporal side
3. Munson sign --------> bulging of Lower Eyelid in Down Gaze
4. Oil droplet reflex -------> by Direct Ophthalmoscopy
5. Scissor Reflex --------> Retinoscopy
6. Bowmans scarring ------- > due to previous hydrops
7. Stromal vertical, fine lines (Vogt Straie) --------> Slit Lamp
8. Epithelial Iron deposits ( Fleischer Ring) ----> S/L cobalt blue
filter
9. Apical Scarring ------> at the apex of the cone
10. Acute hydrops ----> rapture in Descmet’s membrane
11. Prominent corneal Nerves
External Signs:
Slit Lamp findings:
Retro illumination sign

14. Munson sign & Rizzuti Sign:
&

15. Scissor reflex & oil droplet reflex
&

16. Fleischer ring & Vogt Straie:
&

17. Hydrops & Corneal Nerves
&

18. Detection of Keratoconus:
1.Retinoscopy
2. Slit lamp
3. Keratometer
4. Corneal Topography

20. CLASSIFICATION OF KERATOCONUS

21. Classification based on shape of Cone:
• Nipple Shape:
small diameter ( 5mm)
round shape
Easiest to fit with CL
• Oval Cones:
Large dia ( > 5mm)
Often displaced inferiorly
More difficult to fit wit Cl
• Globus Cones:
Largest Dia ( >6mm)
75% of the total cornea is affected
Most difficult to fit with lenses

22. ON THE BASIS OF Keratometer
Reading:
Grades of Keratoconus:
• Mild K ( < 48 D)
• Moderate K ( 48D – 54D)
• Severe K ( > 54D )

23. Associations:
Systemic:
• Downs Syndrome
• Marfan’s Syndrome
• Turner syndrome
• Ehlers- Danlos Syndrom etc
Ocular :
• Persistent Eye rubbing
• Aniridia
• Retinitis pigmentosa

24. Treatment:
• Spectacles:
• RGP ( Rigid Gas Permeable Contact Lenses)
• Keratoplasty

26. 2. Keratoglobus:

27. “the condition in which the entire cornea is
abnormally thin”
Or
Generalized thinning of cornea

29. Onset: at birth
Signs: ectasia is Generalized
acute hydrops occur less commonly
Cornea is more prone to rupture on trauma
Management:
• CL ------ scleral CL
• Surgery ------poor results

30. 3.Pellucid marginal degeneration:
• Inferior corneal thinning ( sometimes superior cornea too)
• Bilateral
• Onset: 20 years to 40 years
• Cresent shape band of inferior cornea extending from 4 – 8 o’clock
• Intact epithelium
• No fleischer rings, no Vogt straie
• High Astigmatism ( against the rule)

31. Treatment:
Spectacles: not usefull
CL: RGP CL
Surgery: keratoplasty

32. Thanks.