Ординатура / Офтальмология / Английские материалы / Rapid Diagnosis in Ophthalmology Series Anterior Segment_Macsai, Machado Fontes_2007

Segment Anterior the of Anomalies Developmental • 1 SECTION

Aniridia

Key Facts

•Most common cause of congenital limbal stem cell deficiency

•Bilateral—can occur as a sporadic isolated condition or in association with Wilms tumor, genitourinary abnormalities, and mental retardation (WAGR) syndrome

•Family members may have variable presentations, with clinical aniridia in some and others with atypical iris defects ranging from radial clefts to atypical colobomas

•Chromosomal aberrations are frequent

•Associated with:

•glaucoma • foveal and optic nerve hypoplasia • nystagmus • progressive keratopathy • cataract

Clinical Findings

•Iris findings range from clinically normal to focal or total absence of pupillary rim

•Often no visible central iris tissue

•A stump of iris tissue peripherally is present in nearly all cases (gonioscopy sometimes needed to visualize)

•Keratopathy:

•starts as thickened and irregular peripheral epithelium with neovascularization

•will extend centrally throughout patient’s lifetime

•chronic epitheliopathy will lead to subepithelial fibrosis and stromal scarring

Ancillary Testing

•Ultrasound biomicroscopy (assess anterior segment anatomy, when corneal scarring limits view)

•A scan (assess posterior segment, control and evaluate glaucoma treatment efficacy in children)

•Impression cytology to evaluate stem cell deficiency

•Optical coherence tomography to confirm foveal hypoplasia if media clear

•Examine family members

•MRI to look for Wilms tumor

Differential Diagnosis

•Peters anomaly

•Congenital glaucoma (can be associated)

•Axenfeld–Rieger syndrome

Treatment

•Refer to geneticist and pediatrician to evaluate possible genetic and systemic abnormalities

•Treat dry eye state aggressively (lubricants, bandage contact lens, tarsorrhaphy)

•Glaucoma control (surgical intervention often required)

•Amblyopia treatment

•Penetrating or lamellar keratoplasty associated with limbal stem cell transplantation

Film Tear the of Disorders • 2 SECTION

Aqueous Deficiency

Key Facts

•Reduced tear production associated with symptoms of ocular discomfort

•More frequent in elderly patients and women (hormone related in most cases)

•Symptoms include:

•dry sensation • irritation • tearing • burning • stinging • foreign body sensation • photophobia • blurry vision • redness • mucous discharge

• increased frequency of blinking

Clinical Findings

•Thin or discontinuous tear meniscus

•Increased debris and unstable tear film

•Delayed tear clearance

Ancillary Testing

•Tear break-up time

•Schirmer testing

•Ocular surface dye staining (fluorescein, rose bengal or lissamine green)

•Impression cytology

Differential Diagnosis

•Meibomian gland disease

•Blink or lid abnormality

•Exposure or neurotrophic keratopathy

Treatment

•Elimination of exacerbating exogenous factors

•Topical lubrication (artificial tears and ointments) or autologous serum

•Topical cyclosporin A

•Punctal occlusion

•Investigate secondary causes (e.g. Sjögren syndrome, HIV infection, vitamin A deficiency)

Prognosis

•Heterogenous condition in severity, duration, and etiology

•Usually not curable and the chronicity may lead to patient frustration

•Initially not sight-threatening and is characterized by troublesome, non-severe symptoms of irritation

•Reversible conjunctival squamous metaplasia and punctate epithelial erosions of the conjunctiva and cornea may develop in moderate to severe cases

•Patients with severe aqueous deficiency can develop complications such as ocular surface keratinization or corneal ulceration, scarring, thinning, or neovascularization

Fig. 2.1 Schirmer test: strip positioned after a drop of anesthetic; read after 5 min.

Fig. 2.2 Tear breakup time. (A) Immediately after administration of fluorescein: uniform distribution of dye, with no staining, and smooth surface. (B) Three seconds after: note “broken” areas of fluorescein, which appear as dark holes.

A

B

Deficiency Aqueous

Film Tear the of Disorders • 2 SECTION

Fig. 2.3 Intense rose bengal staining in the inferior conjunctiva and peripheral cornea.

Fig. 2.4 Delicate rose bengal staining in the inferior conjunctiva and peripheral cornea.

Fig. 2.5 Superficial punctate keratopathy; this alteration is often localized to the inferior cornea.

Film Tear the of Disorders • 2 SECTION

Anterior Blepharitis

Key Facts

•Chronic ocular inflammation that primarily involves eyelashes and eyelid margin

•Common cause of chronic ocular irritation, including conjunctivitis, functional tear deficiency, and keratitis

•Staphylococcal and seborrheic are the most common causes

•Associated dry eye in 50–75% patients

Clinical Findings

•Irritation, redness, burning, watering, asthenopic symptoms

•Scaling and crusting along bases of eyelashes

•Loss of lashes, punctate epithelial erosions, neovascularization, and marginal infiltrates

Ancillary Testing

•Cultures of eyelid margins

•Assess dry eye status

•Biopsy of the eyelid (in areas of lash loss or persistent focal irritation)

•Microscopic evaluation of epilated eyelashes to look for Demodex

Differential Diagnosis

•Bacterial, viral, or parasitic infections

•Immunologic skin condition

•Allergic disorders

•Eyelid tumors

•Aqueous deficiency

Treatment

•Eyelid hygiene with warm compresses

•Topical antibiotics (e.g. erythromycin ointment)

•If significant inflammation, may require brief course of topical corticosteroid ointment to lid margins and eyelashes

Prognosis

•Chronic disease usually not sight-threatening but may lead to recurrent peripheral ulcers

•If untreated, eventual lash loss and lid scarring with trichiasis, corneal scarring, and neovascularization