Definition

• •

  A very rare, congenital, unilateral or bilateral AD or AR condition that has many ocular and systemic syndromic associations ( Table 5.1 ).

  Table 5.1

  Associations of microcornea

  1. Ocular • Cornea plana • Corneal leukoma • Iris abnormalities • Microphakia • Congenital cataract • Glaucoma 2. Syndromic • Turner • Ehlers–Danlos • Weill–Marchesani • Waardenburg • Nance–Horan • Cornelia de Lange

   

Signs

• •

  Adult horizontal corneal diameter is 10 mm or less ( Fig. 5.1 ).

  

• •

  Shallow anterior chamber.

• •

  Other ocular dimensions are normal.

Definition

• •

  A rare, bilateral, congenital condition in which the globes have reduced volume but are otherwise grossly normal.

Signs

• •

  Very high hypermetropia ( Fig. 5.2 ).

  

• •

  Adult corneal diameter is reduced but the lens has a normal volume.

• •

  Short axial length averaging 18 mm.

• •

  Shallow anterior chamber.

• •

  Thick sclera.

• •

  Fundus may show a crowded disc, vascular tortuosity and macular hypoplasia.

Late problems

• •

  Angle-closure glaucoma.

• •

  Uveal effusion characterised by choroidal detachment and retinal detachment ( Fig. 5.3 ).

  

• •

  Retinal detachment.

• •

  Poorly tolerated intraocular surgery.

Definition

• •

  An uncommon, unilateral or bilateral condition in which the axial length of the globe is reduced.

Types

• a.

  Non-colobomatous (simple – Fig. 5.4 and Table 5.2 ).

  

  Table 5.2

  Classification of non-colobomatous microphthalmos

  1. Isolated • Sporadic • Inherited (AD, AR, XL-R) • With persistent anterior fetal vasculature (see Fig. 9.19 ) 2. Microphthalmos with cyst (see Fig. 2.28 ) 3. Intrauterine infections • Rubella • Toxoplasmosis • Cytomegalovirus • Varicella

   

• b.

  Colobomatous ( Fig. 5.5 and Table 5.3 ).

  

  Table 5.3

  Classification of colobomatous microphthalmos

  1. Isolated • Sporadic • Inherited (AD) 2. Syndromic associations • Patau (trisomy 13) • Edward (trisomy 18) • Cat-eye (partial trisomy 22) • Pagon (CHARGE) • Meckel–Gruber • Lenz microphthalmos • Temple–Al Gazali • Delleman • Gorlin–Goltz

   

Definition

• •

  A rare, congenital, bilateral, non-progressive usually XL-R condition that has many systemic associations ( Table 5.4 ).

  Table 5.4

  Systemic associations of megalocornea

  • Marfan syndrome • Apert syndrome • Ehlers–Danlos syndrome • Down syndrome • Osteogenesis imperfecta • Progressive facial hemiatrophy • Renal carcinoma • Mental retardation

   

Signs

• •

  Clear cornea with a horizontal diameter of 13 mm or more ( Fig. 5.6 ).

  

• •

  Very deep anterior chamber.

• •

  Normal intraocular pressure.

• •

  Pigment dispersion.

• •

  High myopia and astigmatism but good visual acuity.

• •

  Lens subluxation may occur as a result of zonular stretching.

Definition

An uncommon, usually bilateral, condition in which the globe is large due to increased intraocular pressure during the first 3 years of life. It has many ocular and systemic associations ( Table 5.5 ).

Signs

• •

  Large cornea with variable oedema and scarring ( Fig. 5.7 ).

  

• •

  Very deep anterior chamber.

• •

  Angle anomalies.

• •

  Horizontal ruptures in Descemet membrane (Haab striae).

• •

  Myopia.

• •

  Optic disc cupping.

Definition

• •

  Refraction is greater than −6D and axial length is greater than 25 mm.

Signs

• •

  Enlargement of the globe and cornea ( Fig. 5.8 ).

  

• •

  Chorioretinal degeneration and maculopathy.

• •

  Predisposition to retinal detachment and glaucoma.

• •

  Staphyloma.

Look for

• •

  Stickler syndrome.

• •

  Cohen syndrome.

• •

  Marfan syndrome.

• •

  Ehlers–Danlos syndrome.

• •

  Fabry disease.

Definition

• •

  A common, acquired condition which is bilateral in 85% of cases, although the severity of involvement may be asymmetric.

• •

  It is associated with many ocular and systemic conditions ( Table 5.6 ).

  Table 5.6

  Associations of keratoconus

  1. Ocular • Vernal disease • Blue sclera • Prominent corneal nerves • Aniridia • Ectopia lentis • Retinitis pigmentosa • Leber congenital amaurosis 2. Systemic • Down syndrome • Ehlers–Danlos syndrome type 6 • Marfan syndrome • Apert syndrome • Turner syndrome • Atopic dermatitis • Osteogenesis imperfecta type 1 • Mitral valve prolapse

   

Signs

• •

  Central or paracentral stromal thinning with inferior apical protrusion ( Fig. 5.9 ).

  

• •

  Munson sign – bulging of the lower lid in downgaze ( Fig. 5.10A right eye; left eye is normal – Fig. 5.10B ).

  

  

• •

  Vogt striae – fine deep vertical stromal stress lines which temporarily disappear on digital pressure ( Fig. 5.11 ).

  

• •

  Acute hydrops – corneal oedema resulting from tears in Descemet membrane ( Fig. 5.12 ).

  

• •

  Variable corneal scarring, depending on severity ( Fig. 5.13 ).

  

Definition

• •

  A very rare, bilateral, congenital condition.

Signs

• •

  Mid-peripheral thinning, resulting in protrusion of the entire cornea ( Fig. 5.14 ).

  

• •

  Very deep anterior chamber.

• •

  Acute hydrops in advanced cases.

Look for

• •

  A syndrome comprising blue sclera, hyperextensible joints and dental abnormalities.

Definition

• •

  An uncommon, acquired, bilateral condition.

Signs

• •

  High astigmatism.

• •

  Inferior, crescent-shaped area of peripheral corneal thinning, 1–2 mm in width, extending from the 4 o’clock to 8 o’clock positions, which is separated from the limbus by normal cornea ( Fig. 5.15 ).

  

• •

  Protrusion located above the area of thinning.

Definition

• •

  A very rare, usually unilateral developmental anomaly that bears no relationship to anterior keratoconus.

Signs

• a.

  Generalis – increase in curvature of the entire posterior corneal surface.

• b.

  Conscriptus – localised central posterior corneal indentation, often associated with opacification ( Fig. 5.16 ).

  

Definition

• •

  A very rare bilateral, congenital condition which never occurs in isolation.

Signs

• •

  Hypermetropia.

• •

  Severe decrease in corneal curvature ( Fig. 5.17 ).

  

• •

  Shallow anterior chamber.

Signs

• •

  Unilateral or bilateral corneal oedema ( Fig. 5.18 ).

  

Look for

• •

  Buphthalmos.

• •

  Ruptures in Descemet membrane (Haab striae) that may be horizontal or concentric with the limbus.

Signs

• •

  Linear usually vertical or oblique ruptures in Descemet membrane associated with oedema ( Fig. 5.19 ).

  

Look for

• •

  Forceps marks on the eyelids or cheeks.

Definition

• •

  A rare, congenital, usually bilateral but asymmetric condition.

Signs

• •

  Opacification and vascularisation of the peripheral or entire cornea ( Fig. 5.20 ).

  

• •

  If only the peripheral cornea is involved, the resulting ‘scleralisation’ makes the cornea appear smaller than normal ( Fig. 5.21 ).

  

Look for

• •

  Peters anomaly (see next).

• •

  Cornea plana.

Definition

• •

  A usually bilateral, congenital condition that varies in severity.

Signs

• •

  Central corneal opacities asymmetric in extent ( Fig. 5.22 ) and an underlying defect of the posterior stroma, Descemet membrane and endothelium.

  

• •

  May be associated with keratolenticular or iridocorneal adhesions best detected by ultrasonography ( Fig. 5.23 ).

  

Definition

• •

  A very rare, congenital, usually unilateral condition.

Signs

• •

  Opaque cornea lined posteriorly with uveal tissue that protrudes beyond the eyelids ( Fig. 5.24 ).

  

• •

  Keratectasia is identical except that it is not lined with uveal tissue.

Signs

• •

  Diffuse corneal clouding caused by fine punctate grey opacities ( Fig. 5.25 ).

  

Presentation

• •

  At or soon after birth with bilateral symmetric diffuse corneal oedema.

Signs

• •

  The appearance may vary from a blue-grey ground-glass appearance ( Fig. 5.26 ) to total opacification ( Fig. 5.27 ).

  

  

Definition

• •

  A very rare, non-progressive AD condition.

Signs

• •

  Diffuse central haze composed of flaky-feathery opacities primarily involving the central anterior stroma.

Signs

• •

  Linear branching lines within the corneal stroma ( Figs 5.28 and 5.29 ).

  

  

Causes

• •

  See Table 5.7 .

  Table 5.7

  Causes of prominent nerve fibres

  1. Local • Fuchs dystrophy • Keratoconus • Posterior polymorphous dystrophy 2. Systemic • Primary amyloidosis • Multiple endocrine neoplasia type II a and b • NF1 • Refsum disease • Leprosy • Hereditary ichthyosis

   

Signs

• •

  Loss of normal corneal lustre ( Fig. 5.30 ) which may be associated with vesicles and bullae ( Fig. 5.31 ).

  

  

Definition

• •

  A very rare, innocuous AD condition.

Signs

• •

  Myriads of tiny epithelial cysts most numerous in the interpalpebral region.

• •

  The lesions appear grey in direct illumination ( Fig. 5.32 ) but clear on retroillumination.

  

Definition

• •

  A common condition which is frequently associated with bilateral spontaneous recurrent corneal erosion.

Signs

• •

  Sparse microcysts, dots and fingerprint-like, or map-like epithelial lesions seen singly or in various combinations ( Fig. 5.33 ).

  

Cause

• •

  Damage may occur during cataract surgery, particularly when associated with problems with lens implantation (pseudophakic bullous keratopathy – Fig. 5.34 ).

  

Causes

• •

  Advanced keratoconus (see Fig. 5.12 ) and occasionally keratoglobus ( Fig. 5.35 ).

  

Definition

• •

  An uncommon bilateral condition which usually occurs in old age.

Signs

• •

  Starts as tiny central excrescences of Descemet membrane (cornea guttata – Fig. 5.36 ) which gradually become confluent.

  

• •

  Subsequent endothelial dysfunction results in stromal oedema and bullous keratopathy.

Signs

• •

  Corneal oedema.

• •

  Severe elevation of intraocular pressure.

• •

  Ciliary injection.

• •

  Fixed dilated pupil.

• •

  Shallow anterior chamber ( Fig. 5.37 ).

  

• •

  Closed angle on gonioscopy.

Definition

• •

  A unilateral condition associated with herpes simplex and occasionally herpes zoster.

Signs

• •

  Oval area of stromal and epithelial oedema with underlying keratic precipitates ( Fig. 5.38 ).

  

• •

  Surrounding ring of stromal opacity (Wessely ring) may be seen in long-standing cases.

Signs

• •

  Endophthalmitis is frequently associated with corneal oedema ( Fig. 5.39 ).

  

Look for

• •

  Conjunctival injection and discharge.

• •

  Fibrinous anterior uveitis and enlarging hypopyon.

• •

  Impaired red reflex.

• •

  Vitreous cells and debris.

Definition

• •

  A common, non-specific, unilateral or bilateral, condition with many diverse causes.

Signs

• •

  Tiny non-specific epithelial defects that stain with fluorescein ( Fig. 5.40 ) and rose Bengal.

  

Causes

Maximal intensity of may indicate the probably aetiology as follows:

• a.

  Superior – vernal disease, superior limbic keratoconjunctivitis, floppy eyelids, poorly fitting contact lenses, chlamydial infection and subtarsal foreign body.

• b.

  Interpalpebral – dry eye, reduced corneal sensation and exposure to ultraviolet light.

• c.

  Inferior – chronic blepharitis, lagophthalmos, trichiasis, rosacea, toxicity from drops and self-induced.

Definition

• •

  SPK is the hallmark of Thygeson disease which is an idiopathic usually bilateral condition that typically affects young adults.

Signs

• •

  Coarse, distinct, granular, greyish, elevated epithelial lesions that may be associated with a mild subepithelial haze ( Fig. 5.41 ).

  

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  1. Anterior chamber
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