metabolic keratopathies Contact lens complications congenital anomalies of the cornea and globe

1. METABOLIC
KERATOPATHIES
JENTRIX MUKONZA
KORNEL AYAGA
MARION KEMBOI

2. CYSTINOSIS
• Rare AR (gene: CTNS) lysosomal storage disorder
characterized by widespread tissue deposition of
cystine crystals
• Forms :Non-nephropathic and intermediate
• Associations :photophobia , epithelial erosions and
visual impairment
• Treatment – cysteamine , systemic and topical

3. CYSTINOSIS

4. MUCOPOLYSACCHARIDOSES
• Group of lysosomal storage disorders involving
enzyme disfunction along the pathway for
breakdown of mucopolysaccharides
• Altered metabolites accumulate intracellularly
• Inheritance mainly AR
• Features include facial coarseness, skeletal
anomalies, heart disease and learning difficulties
• Keratopathy- punctate corneal opacification and
stromal haze

5. MUCOPOLYSACCHARIDOSES

6. WILSON’S DISEASE
• Rare condition involving the widespread abnormal
deposition of copper in tissues
• Caused by a deficiency of caeruloplasmin,
• Presentation- liver disease, basal ganglia
dysfunction or psychiatric disturbances
• Presence of a Kayser Fleischer ring in 95% of
patients
• Anterior capsular cataract is seen in some patients

7. WILSON’S DISEASE

8. LECITHIN-CHOLESTEROL-
ACYLTRANSFERASE
DEFICIENCY(LCAT)
• Disorder of lipoprotein metabolism that has complete
and partial forms that are both AR
• Keratopathy –numerous minute greyish dots
throughout the stroma, concentrated in the periphery
in an arcus –like configuration

9. LECITHIN-CHOLESTEROL-ACYLTRANSFERASE
DEFICIENCY(LCAT

10. IMMUNOPROTEIN DEPOSITION
• Diffuse or focal
• Manifestation of several systemic disease
 multiple myeloma,
 Waldenstrom macroglobulinemia,
Monoclonal gammopathy of unknown cause
Lymphoproliferative disorders
Leukemia
• Corneal involvement in the earliest manifestation
• Bands of punctate flake- like opacities are seen;
posterior stroma
• Treatment – underlying disease, corneal
transplantation

11. IMMUNOPROTEIN DEPOSITION

12. TRYOSINAEMIATYPE 2
(Oculocutaneous tryosinaemia, Richner
Hanhart syndrome)
• Very rare AR disease in which an enzyme deficiency
leads to elevated plasma tyrosine levels
• Painful palmar and plantar hyperkerotic lesions and
variable CNS involvement
• Bilateral pseudo dendritic keratitis with crystalline
edges begins in childhood and causes photophobia,
watering and redness

13. FABRY DISEASE
• X-linked lysosomal storage disorder caused by a deficiency of enzyme
alpha-galactosidase A
• Leads to abnormal tissue accumulation of glycolipid
• Males with the gene and some heterozygous females develop the disease
• Systemic features
Periodic burning pain in the extremities and GIT
Angiokeratomas
Cardiomyopathy
Renal disease

14. FABRY DISEASE
• Ocular manifestations
white to golden brown corneal opacities in a vortex pattern
Wedge or spoke-shaped posterior cataract
Conjunctival vascular tortuosity and aneurysm formation
Retinal vascular tortuosity

15. Angiokeratomas Vortex keratopathy Conjunctival
turtousity and aneurism

16. FABRY DISEASE

17. CONTACT LENSES

19. CONTACT LENSES

20. THERAPEUTIC USES
OPTICAL
Aimed at improving VA when it cannot be achieved by spectacles
• Irregular astigmatism (keratoconus)- rigid contact lenses after
spectacles have failed and before corneal grafting d necessary
• Superficial corneal irregularities- rigid contact lenses, provide a
smoother and regular surface
• Anisometropia – BV cannot be achieved by spectacles due to
aniseikonia, following monocular cataract surgery with high
refractive error correction

21. THERAPEUTIC USES
PAIN RELIEF
• Bullous keratopathy- soft bandage lenses that relieve pain
by protecting exposed nerve endings from shearing forces
of the lids
• Filamentary keratopathy- resistant to topical treatment,
soft contact lenses
• Others include
Thygeson superficial punctate keratitis
Protection of the corneal epithelium from aberrant lashes
in trichiasis
Temporizing measure in entropion prior surgery

22. THERAPEUTIC USES
• FILAMENTARY KERATOPATHY • THYGESON’S SUPERFICIAL PUNCTATE
KERATITIS

23. THERAPEUTIC USES
PROMOTION OF EPITHELIAL HEALING
• Persistent epithelial defects –heal if the corneal epithelium is protected from
rubbing of the lids, allowing the development of hemidesmosomal attachment
to the basement membrane
• Recurrent corneal erosions – associated with basement membrane dystrophy,
require long-term contact lens wear to reduce the recurrence rate, it also
improves comfort

24. THERAPEUTIC USES
PRESERVATION OF CORNEAL INTEGRITY
• A descemetocoele – temporarily capped with a tight-fitting, large diameter soft
or scleral lens to prevent perforation and encourage healing
• Splinting and apposition – of edges of small corneal wound can be achieved by
CL , larger perforations can be sealed with glue followed by insertion of a
bandage CL to protect the glue and prevent irritation of the lids from the glue’s
irregular surface

25. THERAPEUTIC USES
MISCELLANEOUS INDICATIONS
• Ptosis props – to support upper lids in patients
with ocular myopathies
• Maintenance of the fornices –prevent
symblepharon formation in cicatrizing
conjunctivitis
• Drug delivery – enhancement by a hydrogel
lens imbued with topical medication

26. THERAPEUTIC USES

27. COMPLICATIONS
MECHANICAL AND HYPOXIC KERATITIS
• Pathogenesis
Insufficient oxygen transmission through the lens
A tightly fitting contact lens that does not move with blinking impairs tear
circulation
Exacerbated by lid closure if the lens is worn during sleep
Hypoxia leads to anerobic metabolism and lactic acidosis- inhibits the normal
barrier and pump mechanisms of the cornea

28. COMPLICATIONS
MECHANICAL AND HYPOXIC KERATITIS
• Superficial punctate keratitis – most common
complication. Pattern may give clue. E.g. staining at
3 and 9 o’clock is associated with incomplete
blinking and drying in rigid contact lenses
• The tight lens syndrome – indentation and staining
of the conjunctival epithelium in a ring around the
cornea
• Acute hypoxia – epithelial microcysts and necrosis ,
and epithelial blebs. Painful macro erosions may
develop after lens removal

29. COMPLICATIONS
• Chronic hypoxia - result in vascularization and lipid
deposition; superficial peripheral neovascularization of
<1.5 mm is common in myopic contact lens wearers
and can be monitored
• Treatment –depends on the cause
Increasing oxygen permeability by refitting with a
thinner lens, a gas permeable rigid lens silicone
hydrogel soft lens
Modifying lens fit to increase movement
Reducing lens wearing time

30. COMPLICATIONS
IMMUNE RESPONSE (HYPERSENSITIVITY) KERATITIS
Hypersensitivity response to bacterial antigen or the chemicals
used in lens care can lead to the development of sterile
marginal corneal infiltrates
• Signs
Mildly red eye associated with infiltrates , often marginally
located , with no or minimal epithelial defects
• Treatment
Involves cessation of lens wear until resolution occurs.
Topical antibiotics and steroids

31. COMPLICATIONS
TOXIC KERATITIS
• Pathogenesis – acute chemical injury caused by
inadvertently placing a CL on eye without first neutralizing
toxic cleaning agents ; hydrogen peroxide. Chronic
toxicity – resulting from long-term exposure to
disinfecting preservatives such as thiomersal or
benzalkonium chloride
• Signs
Acute pain redness and chemosis
Vascularization and scarring of the cornea
• Treatment
Switching to daily disposable lenses

32. COMPLICATIONS
SUPPURATIVE KERATITIS
• CL wear is the greatest risk factor for the development of bacterial keratitis
• Least for rigid CL
• Bacteria in tear film normally unable to bind to the corneal epithelium but follow
an abrasion in association with hypoxia attach and invade
• Microorganisms can also be introduced by poor lens hygiene/ use of tap water
for rinsing

33. CONGENITAL ANOMALIES OF
THE CORNEA AND GLOBE

34. MICROCORNEA
• Normal neonatal corneal diameter is 10mm and adult diameter of 12mm is reached
by the age of 2yrs
• It is a rare AD unilateral/bilateral condition in which the horizontal corneal diameter
is 10mm or less over 2yrs of age/ less than 9mm in a newborn
• May be hypermetropia and a shallow anterior chamber
• Ocular associations
Glaucoma (angle-closure and open –angle)
Congenital cataract
Leukoma
Persistent fetal vasculature
Coloboma
Optic nerve hypoplasia
Aniridia
Nanophthalmos

35. MICROCORNEA
• Severe microcornea • Microcornea and corneal opacity-
leukoma

36. MICROPHTHALMOS
• A condition in which the entire eye is small with an axial length at least two standard
deviations below the mean for age
• Simple /pure – eye structurally normal apart from a short length
• complex- - eyes with other features of dysgenesis ;a coloboma or orbital cysts
• Unilateral/bilateral; when unilateral the abnormalities may be present in the fellow
eye
• Vision is variably affected with severity
• Typically sporadic, mutations have been implicated
• Around 50% of cases may be associated with systemic abnormalities including CNS
• Potential environmental causes – fetal alcohol syndrome, intrauterine infections

37. MICROPHTHALMOS
• Left microphthalmos • Left microphthalmos with bilateral iris
coloboma

38. NANOPHTHALMOS
• The entire eye is small but is structurally normal
• Both eyes are affected
• Ocular associations
Thickened sclera
Glaucoma
Hypermetropia
Ametropia
Amblyopia
Strabismus
• Management of refractive error and amblyopia is critical
in childhood
• Cataract surgery – high-power lens implant may be
considered to avoid polypseudophakia with precipitating
angle-closure

39. ANOPHTHALMOS
• The complete absence of any visible globe structure; though a microphthalmic
remnant or cyst may be present
• Other associations
Absence of EOM
Short conjunctival sac
Micro blepharon
• Causative factors similar to microphalmos

40. ANOPHTHALMOS
• Bilateral simple anophthalmos • Anophthalmos with cyst

41. MEGALOCORNEA
• Rare, bilateral non-progressive , X-linked recessive condition
• 90% affected individuals are male
• Adult horizontal corneal diameter is 13mm or more, with a
very deep anterior chamber
• High myopia and astigmatism- normal corrected VA
• Lens subluxation- may occur due to zonular stretching /
• Pigment dispersion syndrome is very common

42. MEGALOCORNEA
• Clinical appearance • Trabecular hyperpigmentation due to
pigment dispersion

43. SCLEROCORNEA
• Very rare, usually bilateral condition associated with
cornea plana
• Sporadic cases are common but milder forms can be
inherited as AD and more severe form AR
• Peripheral corneal opacification with no visible border
btwn the sclera and cornea confers the appearance of
apparently reduced corneal diameter in mild-moderate
disease
• Occasionally the entire cornea is involved

44. SCLEROCORNEA
• Moderate • Severe

45. CORNEA PLANA
• Extremely rare bilateral condition in which the cornea is flatter than normal
• The radius of curvature is larger
• Corresponding reduction in refractive power resulting in high hypermetropia
• Two forms:
Cornea plana 1- milder
Cornea plana 2

46. KERATECTASIA
• Very rare , usually unilateral condition thought to
be the result of intrauterine keratitis and
perforation
• Characterized by protuberance between the
eyelids of a severely opacified and sometimes
vascularized cornea
• Often associated with raised IOP

47. POSTERIOR KERATOCONUS
• Sporadic condition in which there is unilateral non-
progressive increase in curvature of the posterior corneal
surface
• The anterior surface is normal
• VA relatively unimpaired- because of the similar refractive
indices of the cornea and aqueous humor
• Types :
Generalized – involvement of the entire posterior corneal
surface
Localized – paracentral or central posterior indentation