4
Conjunctiva and Sclera
Trauma
Foreign Body
Exogenous material on, under, or embedded within the conjunctiva or sclera; commonly dirt, glass, metal, or cilia. Patients usually note foreign body sensation and redness; may have corneal staining, particularly linear vertical scratches due to blinking with a foreign body trapped on the upper tarsal surface. Good prognosis.
• Remove foreign body; evert lids to check tarsal conjunctiva.
• Topical broad-spectrum antibiotic (polymyxin B sulfate-trimethoprim [Polytrim] drops or bacitracin ointment qid).
Laceration
Partial-thickness or full-thickness cut in conjunctiva with or without partial-thickness cut in the sclera; very important to rule out open globe (see below); good prognosis.
• Seidel test for suspected open globe (see below).
• Topical broad-spectrum antibiotic (gatifloxacin [Zymar] or moxifloxacin [Vigamox] qid).
• Conjunctival and partial-thickness scleral lacerations rarely require surgical repair.
Open Globe
Full-thickness defect in eye wall (cornea or sclera), commonly from penetrating or blunt trauma; the latter usually causes rupture at the limbus, just posterior to the rectus muscle insertions, or at previous surgical incision sites; double penetrating injuries are called perforations; an open globe may also be due to corneal or scleral melting.
Associated signs include lid and orbital trauma, corneal abrasion or laceration, wound dehiscence, positive Seidel test (see Laceration section in Chapter 5), low intraocular pressure, flat or shallow anterior chamber, anterior chamber cells and flare, hyphema, peaked pupil, iris transillumination defect, sphincter tears, angle recession, iridodialysis, cyclodialysis, iridodonesis, phacodonesis, dislocated lens, cataract, vitreous and retinal hemorrhage, commotio retinae, retinal tear, retinal detachment, choroidal rupture, intraocular foreign body or gas bubbles, and extruded intraocular contents. Guarded prognosis.
Subconjunctival Hemorrhage
Diffuse or focal area of blood under the conjunctiva. Appears bright red, otherwise asymptomatic. May be idiopathic, associated with trauma, sneezing, coughing, straining, emesis, aspirin or anticoagulant use, or hypertension, or due to an abnormal conjunctival vessel. Excellent prognosis.
• Reassurance if no other ocular findings.
• Consider blood pressure measurement if recurrent.
• Medical or hematology consultation for recurrent, idiopathic, subconjunctival hemorrhages, or other evidence of systemic bleeding (ecchymoses, epistaxis, gastrointestinal bleeding, hematuria, etc.).
Telangiectasia
Definition
Abnormal, dilated conjunctival capillary formation.
Symptoms
Asymptomatic red spot on eye; patient may have epistaxis and gastrointestinal bleeding depending on etiology.
Signs
Telangiectasia of conjunctival vessels, subconjunctival hemorrhage.
Differential Diagnosis
Idiopathic, Osler–Weber–Rendu syndrome, ataxia–telangiectasia, Fabry’s disease, Sturge–Weber syndrome.
Evaluation
• Consider CT scan for multisystem disorders.
• Medical consultation to rule out systemic disease.
Prognosis
Usually benign; may bleed; depends on etiology.
Microaneurysm
Definition
Focal dilation of conjunctival vessel.
Symptoms
Asymptomatic; may notice red spot on eye.
Signs
Microaneurysm; may have associated retinal findings.
Differential Diagnosis
Diabetes mellitus, hypertension, sickle cell anemia (Paton’s sign), arteriosclerosis, carotid occlusion, fucosidosis, polycythemia vera.
Evaluation
• Complete ophthalmic history and eye exam with attention to conjunctiva and ophthalmoscopy.
• Check blood pressure.
• Lab tests: Fasting blood glucose (diabetes mellitus), sickle cell prep, hemoglobin electrophoresis (sickle cell).
• Medical consultation.
Prognosis
Usually benign.
Dry Eye Disease (Dry Eye Syndrome, Keratoconjunctivitis Sicca)
Definition
Sporadic or chronic ocular irritation with visual disturbance due to a tear film and ocular surface abnormality.
Etiology
Any condition that causes a deficiency or imbalance in the aqueous, lipid, or mucin components of the tear film. Dry eye can be classified by mechanism (decreased tear production or increased tear evaporation), category (lid margin disease [i.e., blepharitis, meibomitis], no lid margin disease, altered tear distribution/clearance), or severity (Table 4-1). It is usually multifactorial with an inflammatory component; tear hyperosmolarity and tear film instability create a cycle of ocular surface inflammation, damage, and symptoms.
Aqueous-Deficient Dry Eye
Characterized by abnormal lacrimal gland function causing decreased tear production.
Sjögren syndrome
Dry eye, dry mouth, and arthritis with autoantibodies (to Ro (SSA) and / or La (SSB) antigens) and no connective tissue disease (primary, > 95% female) or with connective tissue disease, including rheumatoid arthritis and collagen vascular diseases (secondary).
Non-Sjögren
Hypofunction of the lacrimal gland due to other causes:
Primary lacrimal gland deficiencies
Age-related (historically labeled KCS), congenital alacrima, familial dysautonomia (Riley Day syndrome).
Secondary lacrimal gland deficiencies
Lacrimal gland infiltration, lymphoma, sarcoidosis, amyloidosis, AIDS, graft-versus-host disease, lacrimal gland ablation or denervation.
Obstruction of the lacrimal ducts
Cicatrizing conjunctivitis (Stevens–Johnson syndrome, ocular cicatricial pemphigoid, trachoma, chemical burns, radiation).
Neurosecretory block
Sensory (corneal surgery, contact lens wear, diabetes, neurotrophic keratopathy), motor (cranial nerve VII damage, systemic medications (β-blockers, antimuscarinics, antidepressants, diuretics)).
Evaporative Dry Eye
Characterized by normal lacrimal gland function but increased tear evaporation.
Intrinsic causes
Meibomian gland dysfunction (MGD)
Primary, secondary, simple, or cicatricial (see Meibomitis and Acne Rosacea sections in Chapter 3).
Lid / globe abnormalities
Conditions that result in a malposition, lagophthalmos, or proptosis with exposure of the ocular surface (see Exposure Keratopathy in Chapter 5).
Reduced blink rate
Reading/computer work (decreases blink rate by up to 60%), Parkinson’s disease.
Medications
Systemic retinoids (Accutane).
Extrinsic causes
Malnutrition or malabsorption causes conjunctival xerosis and night blindness (nyctalopia) with progressive retinal degeneration; major cause of blindness worldwide.
Topical drugs
Anesthetics, preservatives (BAK – benzalkonium chloride).
Contact lens wear
Approximately 50% of contact lens wearers have dry eye symptoms.
Ocular surface disease
Cicatrizing conjunctivitis (see above), allergic conjunctivitis.
Epidemiology
Dry eye disease is estimated to affect 5–30% of the population ≥ 50 years old and is more common in women. Associated factors include age, hormone levels (menopause, androgen deficiency), environmental conditions (low humidity, wind, heat, air-conditioning, pollutants, irritants, allergens), and smoking.
Symptoms
Irritation, dryness, burning, stinging, grittiness, foreign body sensation, tearing, red eye, discharge, blurred or fluctuating vision, photophobia, contact lens intolerance, increased blinking; symptoms are variable and exacerbated by wind, smoke, and activities that reduce the blink rate (i.e., reading and computer work).
Signs
Conjunctival injection, decreased tear break-up time (< 10 seconds), decreased tear meniscus height (< 0.20 mm), excess tear film debris, corneal filaments, dry corneal surface, irregular and dull corneal light reflex, corneal and/or conjunctival staining with lissamine green, rose bengal, and fluorescein (typically in the interpalpebral space or on the inferior cornea); may have Bitot’s spot (white, foamy patch of keratinized bulbar conjunctiva [pathognomonic for vitamin A deficiency]), conjunctivochalasis (loosened bulbar conjunctiva resting on lid margin); severe cases can cause corneal ulceration, descemetocele, or perforation. May also have signs of an underlying condition (i.e., rosacea, blepharitis, lid abnormality).
Differential Diagnosis
See above; also allergic conjunctivitis, medicamentosa, contact lens overwear, trichiasis.
Evaluation
• Complete eye exam with attention to lids, tear film (break-up time and height of meniscus), conjunctiva, and cornea (staining with lissamine green or rose bengal [dead and degenerated epithelial cells], and/or fluorescein [only dead epithelial cells]).
• Schirmer’s test: Two tests exist, but they are usually not performed as originally described. One is done without and one is done with topical anesthesia. The inferior fornix is dried with a cotton-tipped applicator, and a strip of standardized filter paper (Whatman #41, 5 mm width) is placed in each lower lid at the junction of the lateral and middle thirds. After 5 minutes, the strips are removed and the amount of wetting is measured. Normal results are 15 mm or greater without anesthesia (basal + reflex tearing), and 10 mm or greater with topical anesthesia (basal tearing). Schirmer’s test often produces variable results so its usefulness may be limited.
• Alternatively, consider the phenol red thread test: Similar to the Schirmer’s test but uses a special cotton thread that changes color as tears are absorbed for 30 seconds; less irritating and may be more reproducible.
• Lab tests: Consider tear lactoferrin and lysozyme (decreased), matrix metalloproteinase 9 (MMP-9) (> 40 ng/mL), tear osmolarity (> 316 mOsm / L), and impression cytology (detects reduced goblet cell density and squamous metaplasia; rarely used clinically).
• Consider corneal topography (computerized videokeratography): Irregular or broken mires with resulting abnormal topography and blank areas due to poor-quality tear film and dry spots. Surface regularity index (SRI) value correlates with severity of dry eye.
• Electroretinogram (reduced), electro-oculogram (abnormal), and dark adaptation (prolonged) in vitamin A deficiency.
• Consider medical consultation for systemic diseases.
Prognosis
Depends on underlying condition; severe cases may be difficult to manage.
Inflammation
Definition
Chemosis
Edema of conjunctiva; may be mild with boggy appearance or massive with tense ballooning.
Follicles
Small, translucent, avascular mounds of plasma cells and lymphocytes found in epidemic keratoconjunctivitis (EKC), herpes simplex virus, chlamydia, molluscum, or drug reactions.
Granuloma
Collection of giant multinucleated cells found in chronic inflammation from sarcoid, foreign body, or chalazion.
Hyperemia
Redness and injection of conjunctiva.
Membranes
A true membrane is a firmly adherent, fibrinous exudate that bleeds and scars when removed; found in bacterial conjunctivitis (Streptococcus species, Neisseria gonorrhoeae, Corynebacterium diphtheriae), Stevens–Johnson syndrome, and burns. A pseudomembrane is a loosely attached, avascular, fibrinous exudate found in EKC and mild allergic or bacterial conjunctivitis.
Papillae
Vascular reaction consisting of fibrovascular mounds with central vascular tuft; nonspecific finding in any conjunctival irritation or conjunctivitis; can be large (“cobblestones” or giant papillae).
Phlyctenule
Focal, nodular, vascularized infiltrate of polymorphonuclear leukocytes and lymphocytes with central necrosis due to hypersensitivity to Staphylococcus species, Mycobacterium species, Candida species, Coccidioides, Chlamydia, or nematodes; located on the bulbar conjunctiva or at the limbus; can march across the cornea, causing vascularization and scarring behind the leading edge.
Symptoms
Red eye, swelling, itching, foreign body sensation; may have discharge, photophobia, and tearing.
Signs
See above; depends on type of inflammation.
Differential Diagnosis
Any irritation of conjunctiva (allergic, infectious, autoimmune, chemical, foreign body, idiopathic).
Evaluation
• Lab tests: Cultures and smears of conjunctiva, cornea, and discharge for infectious causes.