Common cases: Anterior Chamber and Iris

Dr. Riyad BanayotDr. Riyad Banayot

Anterior Chamber Iris Glaucoma Lens

Depth Cells and flare Foreign bodies (Molteno's tube and

silicone oil and less commonly heavy liquid)

The anterior chamber should be examined for depth if you suspect the anterior chamber is shallow especially if there were signs of previous acute angle closure glaucoma

The angle is assessed by the Van Herick's method

Depth of peripheral anterior chamber (PAC) compared to the adjacent corneal thickness (CT) at temporal corneal limbus at 60° angle

The technique uses the following set-up: Optical section 60° between observation and illumination Full slit length Magnification approximately x 15 Low to medium illumination Place optical section just inside limbus. Assuming the corneal thickness = 1 unit, assess the

width of the "aqueous gap" or peripheral anterior chamber from corneal endothelium to iris

Grade Ratio of aqueous gap/cornea Clinical interpretation

4 > 1/2 : 1 Closure impossible

3 = 1/2 - 1/4 : 1 Closure impossible

2 = 1/4 : 1 Closure possible 1 < 1/4:1 Closure likely

with full dilatation0 nil Closed

Mutton fat keratic precipitates Fine stellate keratic precipitates in  Fuch's heterochromic cyclitis

Cells and flare are common signs in uveitis

Koeppe nodules at the pupil margin Busacca nodule

Both conditions are indicative of granulamatous inflammation

Molteno's tube is usually associated with the following signs: Previous trabeculectomy (very often there are more than one trabeculectomy with several iridectomies)  Neovascular glaucoma  Iridocorneal endothelial syndrome Advanced glaucomatous disc

If the tube is short, it may not be apparent unless you get the patient to look down

Emulsified silicone oil in the anterior chamber (hyperoleon)

Globules of heavy liquid in inferior anterior chamber

Examine the posterior segment for the presence of previous retinal detachment, proliferative vitreoretinopathy and advanced proliferative diabetic retinopathy

The superior anterior chamber contains fine suspension of silicone oil.

The oil may appear milky owing to emulsification (so-called inverted hypopyon).

Look for: Complications associated

with the oil (i.e. band keratopathy and cataract)

Presence of Anton's iridotomy (this is iridectomy performed at 6 O'clock in aphakic patient to prevent pupillary block)

Previous retinal detachment

Internal tamponade in giant retinal tears, complex or traumatic retinal detachments

Closure of breaks which are complicated by proliferative diabetic retinopathy or proliferative vitreo-retinopathy

Dissection of epiretinal membranes and flattening of the retina

Midperipheral iris transillumination in pigment dispersion syndrome

Diffuse iris transillumination in albinism

Sectoral iris transillumination in herpes zoster iritis. The feature results from iris vasculitis. Note: the transillumination can also be diffuse if the involvement is extensive

Sectoral iris transillumination in a patient with iris prolapse during phaco.

Note the area involved corresponds to the corneal incision site for the phaco.

Diffuse mild iris transillumination in a patient with senile iris trophy

The iris tissue is absent inferonasally so that the margin of the lens is visible inferiorly (there may be coloboma of the lens or inferior cataract).

The condition is usually bilateral. There may be microphthalmos. 

Examine the fundus (fundi) for extension of the coloboma  which may involve the choroid and the optic disc

The patient may have esotropia (or rarely exotropia) if the coloboma involves the macular area

Iris Coloboma

Coloboma of the choroid and optic disc

CHARGE syndrome in which there is coloboma, heart defects, choanal atresia, retarded growth, genital abnormalities and ear anomalies.

Merckerl-Gruber's syndrome in which there are microcephaly, occipital encephalocele, congenital heart defects, polydactly, facial clefts and polycystic renal and hepatic diseases.

Sjogren-Larsson's syndrome with microphthalmos and mental retardation.

is a common physical sign in SL examination. Unless you perform retro-illumination, the sign may

be missed. The distribution of the transillumination can give

clue to the underlying cause.  Common types:

Peripapillary: Pseudoexfoliation syndrome Mid-periphery: Pigment dispersion syndrome Diffuse: albinism, previous acute angle closure glaucoma,

Fuchs' heterochromic cyclitis, senile iris atrophy, post-cataract extraction

Sectoral Herpes zoster iritis (look for scars on the forehead from

previous ophthalmic shingles) Iris prolapse during Phacoemulsification (this is usually at the

clock hour corresponding to the entry site)

There is a pigmented lesion on the iris (describe the color, the edge, is it flat/elevated.

Look for signs of malignancy (e.g. abnormal iris vessels around or within the tumor, ectopia uvea and sectoral cataract at the site of the lesion.

Examine the posterior segment for any extension; alternatively, the iris lesion (especially if it  is at the angle) may be an extension from a lesion behind the iris

look at the sclera on the side of the lesion for any dilated vessels (sentinel vessels) indicating that there may be a lesion at the ciliary body with anterior extension

iris naevus

Ectopia uvea

There is a pigmented lesion on the iris (describe the color, the edge, is it flat/elevated.

Look for signs of malignancy (e.g. abnormal iris vessels around or within the tumor, ectopia uvea and sectoral cataract at the site of the lesion.

Examine the posterior segment for any extension; alternatively, the iris lesion (especially if it  is at the angle) may be an extension from a lesion behind the iris

look at the sclera on the side of the lesion for any dilated vessels (sentinel vessels) indicating that there may be a lesion at the ciliary body with anterior extension Iris melanoma with

intrinsic blood vessels

Iris naevus / melanoma Primary iris cyst (Epithelial cyst arises secondary to splitting of the

posterior epithelial layers of the iris. Stromal cysts are found early in life, appears as an unilateral, non-pigmented, thin walled lesions with few blood vessels and stretches over the anterior surface)

Secondary cysts (post surgical or trauma, frequently enlarge and lead to serous complications such as glaucoma and inflammation

Iris foreign body Lymphoma or leukemia Uveitis with granulomatous diseases such as TB, syphilis or sarcoidosis Lisch nodules in neurofibromatosis Juvenile xanthogranuloma. Appears as an orange-tan nodular or

sessile segmental thickening of the iris. Seen during early years of life, regress spontaneously with steroid treatment, radiation therapy and rarely iridectomy is required. Diagnosis: look for cutaneous manifestations and to perform biopsy on the skin lesions (Touton's giant cells)

Leiomyoma of the iris (from the deeper layers of the iris at the zone of the sphincter muscle. An uncommon condition and usually appears diffuse and flat with a predilection for the pupillary region of the iris)

Vascular lesion of the iris such as haemangioma Metastatic lesion

Lisch nodules in neurofibromatosis

The main diagnosis is between iris naevus and iris melanoma.

Lesion suggestive of melanoma include ectopia uveae, intrinsic vessels, sectoral lens opacity, glaucoma, uveitis and rapid growth.

In the majority of cases, the lesion is observed for growth with regular photographic monitoring.

If the lesion enlarges rapidly, iridectomy (where only iris is involved) or iridocyclectomy (if the angle is involved) may be performed

95% life expectancy for iris melanoma following surgical excision

The iris is completely absent or rudimentary. The edges of the lens are clearly visible. There may be cataract with or without subluxation. The cornea may contain pannus and dermoid.

Patients C/O photophobia and has nystagmus (usually pendular ).

Examine the fundus for macular hypoplasia or glaucomatous disc changes.

Examine the flank for nephrectomy scar for Wilm's tumour (Miller's syndrome).

Aniridia

Aniridia Normal eye

Deletion of the short arm of chromosome 11 in aniridia is associated with systemic features including Wilm's tumour, mental retardation and GU abnormalities.

Not all aniridia has deletion of chromosome 11.

The inheritance of aniridia may be autosomal dominant, autosomal recessive or sporadic.

In aniridia, the rudimentary iris becomes attached to the trabecular meshwork as the patients grows.

This lead to impaired aqueous drainage. Glaucoma is uncommon at birth.

Heterochromia iridis

Test the patient's VA and pupil response (in siderosis bulbi the darker eye has poor vision and the pupil is usually dilated and does not react to light).

Look for siderosis bulbi in which there are usually signs of penetrating injury or Fuchs' heterochromic iridis)

Look for any signs of mild ptosis or anisocoria on the side of the lighter iris for congenital Horner's syndrome

Examine the eye for any retained foreign body or signs of previous penetrating injury.

The optic disc may show glaucomatous damage. Look for diffuse keratitic precipitate, flare and

posterior subcapsular cataract in Fuchs‘ heterochromic iridis.

Congenital: can be hypo or hyperchromic Causes of hyperchromic iris:

Iris naevus Drug-induced as in unilateral use of

Latanoprost Rubeotic iridis Siderosis bulbi

Causes of hypochromic iris: Chronic inflammation such as Fuchs'

heterochromic cyclitis Congenital Horner's syndrome Trauma

Iris heterochromia Pupil dilatation and poor reaction to light Cataract Brown deposits on the anterior lens Vitreous opacities Peripheral retinal pigmentation which eventually

progresses to diffuse retinal pigmentation Narrowed retinal vessels Optic disc atrophy Secondary glaucoma due to accumulation of

iron in the trabecular meshwork

Initially shows an increased a-wave and normal b-wave.

With time, the amplitude of b-wave decreases.

Eventually, the ERG becomes extinguished.

A patient with left-sided siderosis bulbi. Note the dark iris and dilated pupil.

Heterochromic iridis in a patient with congenital Horner's syndrome. Note the miosis and mild ptosis on the side with lighter iris

The patient has blond hair and poliosis (oculocutaneous albinism ).

There may be obvious nystagmus (usually pendular) and convergent strabismus.

The iris shows transillumination.

Fundal examination may reveal macular hypoplasia (shown by absent foveal reflex).

The temporal arcade of the retinal vessels run almost horizontally.

The retina is hypopigmented (lack of RPE pigment) making the choroidal vasculature easily visible

Ocular albinism is usually X-linked recessive (also known as Nettleship-Falls type)

Oculo-cutaneous albinism is commonly autosomal recessive.

Patients who can produce pigmentation have a less severe visual impairment than those who cannot produce any pigmentation.

This can be determined using the hair bulb test (in patients over the age of 4). In this test, the hair bulb is incubated in a solution containing tyrosine. In patients who are tyrosinase-positive, pigmentation of the hair occurs which is absent in patients who are tyrosinase-negative.

In albinism there is complete decussation of the visual pathway.

Therefore, monocular stimulation of the retina will only give cortical signal on the contralateral cortex.

Life expectancy is usually normal. But, some forms of albinism are

associated with life threatening conditions.

The two best known are: Chédiak-Higashi's syndrome (easy

susceptibility to recurrent infection due to abnormal immunity)

Hermansky-Pudlak's syndrome (easy susceptibility to bruising and bleeding)