Chapter Notes: Conjunctiva

Table of Contents
1. Anatomy of Conjunctiva
2. Acute Membranous Conjunctivitis
3. Pseudomembranous Conjunctivitis
4. Adenoviral Keratoconjunctivitis
5. Trachoma
6. Pathology of Trachoma
7. Sequelae of Trachoma
8. Adult Inclusion Conjunctivitis
9. Acute Hemorrhagic Conjunctivitis
10. Allergic Conjunctivitis
11. Degenerations of the Conjunctiva
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Anatomy of Conjunctiva

The conjunctiva consists of three main layers:

• Epithelium
• Adenoid Layer
• Fibrous Layer

Epithelium: This layer includes:

• Epithelial cells.
• Goblet cells: Found among epithelial cells across all conjunctival regions, these mucin-secreting glands are most densely located in the nasal bulbar conjunctiva, followed by the inferior fornix.
• Melanocytes.
• Langerhans cells: These cells are involved in antigen presentation, lymphokine, and prostaglandin production, but are not phagocytic.

Adenoid Layer: Also known as the lymphoid layer, it consists of a delicate connective tissue network containing lymphocytes.

Fibrous Layer: A mesh of collagenous and elastic fibers that houses the conjunctiva's blood vessels and nerves. The adenoid and fibrous layers together form the substantia propria.

Conjunctivitis: This is inflammation of the conjunctiva characterized by conjunctival hyperemia (redness) and discharge, which may be watery, mucoid, mucopurulent, or purulent.

Clinical Features:

• Conjunctival redness.
• Foreign body sensation.
• Mild photophobia.
• Eye irritation or discomfort.
• Discharge.
• Blurred vision or halos (with mucopurulent discharge).
• Chemosis (conjunctival swelling).
• Petechial hemorrhages (often linked to pneumococcal infection).
• Subconjunctival hemorrhages (associated with Enterovirus-70, Adenovirus, or Coxsackievirus A-24).

Causes: Conjunctivitis can be bacterial, viral, chlamydial, or allergic.

Bacterial Conjunctivitis: The most common cause is Staphylococcus aureus, which is also frequently associated with hordeolum and phlyctenular conjunctivitis. Other causative organisms include:

• Staphylococcus epidermidis.
• Streptococcus pneumoniae (pneumococcus, linked to subconjunctival hemorrhages).
• Streptococcus haemolyticus (causes pseudomembrane formation).
• Corynebacterium diphtheriae (causes membranous conjunctivitis).

Acute Membranous Conjunctivitis

Acute membranous conjunctivitis is a type of eye infection that leads to the formation of a genuine membrane on the palpebral conjunctiva, which is the inner surface of the eyelids. This membrane is not just a thin layer; it is quite thick and when attempted to be removed, it causes bleeding from the underlying tissue.

Causes:

• The primary cause of acute membranous conjunctivitis is Corynebacterium diphtheriae, the bacterium responsible for diphtheria.
• In some cases, a virulent strain of Streptococcus haemolyticus may also be responsible for this condition.

Affected Population:

• This condition mainly affects children between the ages of 2 and 8 years who have not been immunised against diphtheria.

Stages of Acute Membranous Conjunctivitis:

The condition is typically divided into three stages:

1. Stage of Infiltration:

• During this initial stage, the eyelids become swollen and firm, and there is minimal discharge from the conjunctiva.
• The conjunctiva is covered by a grey-yellow membrane that, when peeled away, causes bleeding and leaves a raw area behind.
• There is also an enlargement of the preauricular lymph nodes, which are located near the ear and are part of the lymphatic system.

2. Stage of Suppuration:

• In this stage, there is a significant increase in purulent (pus-filled) discharge from the eye.
• Pain associated with the condition decreases, and the membrane covering the conjunctiva starts to slough off.

3. Stage of Cicatrisation:

• This stage marks the healing process, leading to cicatrisation, which is the formation of scar tissue.
• However, this stage may also be associated with complications such as:
  • Trichiasis:. condition where the eyelashes grow inward, causing irritation to the eye.
  • Conjunctival xerosis: dryness of the conjunctiva, which can lead to discomfort and other issues.
  • Symblepharon: an adhesion between the palpebral conjunctiva (inner eyelid) and the bulbar conjunctiva (the white part of the eyeball), which can restrict eye movement.
  • Entropion:. condition where the eyelid turns inward, leading to irritation of the eye, similar to trichiasis.

Treatment:

• Administer penicillin eye drops every 30 minutes.
• Provide anti-diphtheric serum hourly.
• Apply atropine eye ointment and broad-spectrum antibiotic ointment at night.
• Give intramuscular injection of penicillin for ten days.
• Administer intramuscular injection of anti-diphtheric serum immediately.

Pseudomembranous Conjunctivitis

• Pseudomembranous conjunctivitis is a type of acute conjunctivitis characterized by the formation of a pseudomembrane on the conjunctiva. This membrane does not bleed when removed, and the underlying conjunctival tissue remains intact.
• Corynebacterium diphtheriae is often associated with this condition due to its significant pathogenicity.
• Other potential causative agents include: Streptococcus haemolyticus, H. influenzae, Herpes simplex virus, severe adenoviral infections, Gonococcal infections, and autoimmune conjunctivitis.
• Treatment for pseudomembranous conjunctivitis typically involves: Topical antibiotics and ointments.
• Irrigation of the conjunctiva to remove discharge and debris.
• Avoiding steroids and bandages, as they may worsen the condition.
• Anti-inflammatory and analgesic medications to relieve symptoms.

Viral Conjunctivitis

Keratoconjunctivitis is a frequent viral condition that affects the eyes.

Various viruses can lead to viral conjunctivitis, including:

• Adenovirus
• HSV (Herpes Simplex Virus)
• Herpes zoster
• Pox virus
• Myxovirus
• Paramyxovirus

Adenoviral Keratoconjunctivitis

Adenoviral keratoconjunctivitis commonly affects children, particularly those with an upper respiratory infection (URI).

Causes of Adenoviral Keratoconjunctivitis:

• Pharyngoconjunctival fever (PCF)
• Epidemic keratoconjunctivitis (EKC)
• Symptoms of adenoviral keratoconjunctivitis include:
  • Watering of the eyes
  • Discomfort or irritation in the eyes
  • Sensitivity to light (photophobia)
• Follicular response
• Preauricular adenopathy (swelling of the lymph nodes in front of the ear)
• In severe cases, additional symptoms may include:
  • Subconjunctival hemorrhage (bleeding underneath the conjunctiva)
  • Pseudomembranes (false membranes on the conjunctiva)
  • Keratitis (inflammation of the cornea)

Angular Conjunctivitis

Also referred to as "diplobacillus conjunctivitis," this condition is primarily caused by Moraxella axenfeldii. In some cases, it can also be triggered by Staphylococcus aureus.

Moraxella is a type of diplobacillus commonly found in the nasal passages of healthy individuals.

Symptoms include:

• Congestion of the conjunctiva at the intermarginal strip, which is especially noticeable at the inner and outer canthi.
• Excoriation (scratching or irritation) of the skin at these angles.

Complications

• Blepharitis
• Clear, shallow corneal ulcers, which can be associated (though rarely) with hypopyon, the accumulation of pus in the anterior chamber of the eye.

Treatment options include:

• Oxytetracycline eye ointment
• Zinc lotion, which works by inhibiting proteolytic enzymes
• Zinc oxide ointment, used at night

Trachoma

Trachoma, also known as "Egyptian Ophthalmia," is a leading cause of preventable blindness around the globe.

This condition is triggered by specific types of the bacterium Chlamydia trachomatis, namely serotypes A, B, Ba, and C. In contrast, serotypes D-K are responsible for Adult Inclusion Conjunctivitis, which is sometimes called "Swimming-pool Conjunctivitis."

SAFE Strategy

The SAFE strategy is an approach used to control trachoma in communities. It includes four key components:

• Surgery: This involves surgical intervention to correct complications caused by trachoma.
• Antibiotics: The use of antibiotics to treat and prevent trachoma.
• Facial cleanliness: Promoting good hygiene practices to reduce the spread of the disease.
• Environment: Improving environmental conditions that contribute to the spread of trachoma.

Chemotherapy for trachoma can be administered in two ways:

• Mass treatment. This approach, also known as blanket treatment, is used when moderate to severe trachoma affects more than 5% of children under 10 years old in a community. The antibiotic Azithromycin is commonly used for this purpose.
• Selective treatment. In this method, the entire at-risk population is screened for active trachoma, and only those diagnosed with the condition receive treatment.

Trachoma primarily impacts children and is characterized by symptoms such as:

• Severe itching of the eyes
• Excessive tearing or watering of the eyes

The conjunctival reaction in trachoma can manifest in two forms:

• Follicular: This refers to the presence of small, round bumps (follicles) on the conjunctiva, which is the clear membrane covering the white part of the eye.
• Papillary: This indicates the presence of larger, raised areas (papules) on the conjunctiva.

O/E:

• Sago-grain-like follicles on the upper palpebral conjunctiva.
• Herbert's follicles located on the superior limbus. In the scarring stage, these cicatrise into Herbert's pits.
• In later stages, there is linear scarring at the sulcus subtarsalis, known as Arlt's line.

Pathology of Trachoma

• Chlamydia trachomatis is epitheliotrophic and is typically found in conjunctival scrapings in colony form within epithelial cells, appearing as Halberstaedter-Prowazek inclusion bodies.
• The inclusion initially contains many initial bodies that divide until the cell is filled with numerous elementary bodies embedded in a carbohydrate matrix, forming the inclusion body.
• There is lymphocytic infiltration affecting the entire adenoid layer of the impacted conjunctiva.
• Special collections of lymphocytes create follicles.
• These follicles often exhibit necrosis and contain large multinucleated cells, known as Leber's cells.
• In chronic cases, fibrous tissue develops around the follicles, resulting in cicatricial bands.

Sequelae of Trachoma

• Trachoma can lead to several complications, including:
• Entropion: This is a condition where the eyelid turns inward, causing the eyelashes to rub against the cornea.
• Trichiasis: This condition involves the misdirection of eyelashes, which can irritate the cornea and lead to further complications.
• Corneal opacity: This refers to clouding of the cornea, which can impair vision.
• Corneal ulceration: This is a serious condition where an ulcer forms on the cornea, leading to pain, redness, and potential vision loss.
• Corneal perforation: This is a severe complication where the cornea develops a hole, which can be sight-threatening.

1. Eyelids

• Trichiasis: This condition involves the misdirection of eyelashes, causing them to grow inward towards the eye.
• Entropion: Entropion is the inward folding of the eyelid, which can irritate the eye's surface.
• Tylosis: Tylosis refers to the thickening of the eyelid skin, often due to chronic irritation.
• Ptosis: Ptosis is the drooping of the upper eyelid, which can affect vision and eye appearance.
• Madarosis: Madarosis is the loss of eyelashes or eyebrows, which can be a sign of underlying conditions.
• Ankyloblepharon: Ankyloblepharon is a condition where the eyelids are partially or completely fused, affecting eyelid function.

2. Conjunctiva

• Concretions: These are small, calcified deposits that can form on the conjunctiva, often without causing symptoms.
• Pseudocyst:. pseudocyst on the conjunctiva is a fluid-filled sac that is not a true cyst, usually arising from tissue injury or inflammation.
• Xerosis: Xerosis refers to dryness of the conjunctiva, which can lead to discomfort and irritation.
• Symblepharon: Symblepharon is the abnormal adhesion of the conjunctiva to the eyelid or globe, which can restrict eye movement.

3. Cornea

• Corneal Opacity: This refers to the clouding of the cornea, which can impair vision.
• Corneal Ectasia: Corneal ectasia is the abnormal thinning and bulging of the cornea, leading to visual distortion.
• Corneal Xerosis: Corneal xerosis is the dryness of the cornea, which can result in discomfort and increased risk of infection.
• Total Corneal Pannus: This condition involves the invasion of blood vessels and inflammatory tissue into the cornea, often due to chronic irritation.

4. Other Sequelae

• Chronic Dacryocystitis: This is the persistent inflammation of the tear sac, leading to swelling and discomfort.
• Chronic Dacryoadenitis: Chronic dacryoadenitis involves the long-term inflammation of the lacrimal gland, causing pain and swelling.
• Secondary Glaucoma: Rarely, scarring of the episcleral drainage channel can lead to secondary glaucoma, a condition characterized by increased intraocular pressure.
• Corneal Ulcers: Trachoma can lead to corneal ulcers due to irritation from concretions or trichiasis, especially when compounded by bacterial infection.

Note: Dacryoadenitis is the inflammation of the lacrimal gland, resulting in swelling and discomfort in the affected area.

Classification of Trachoma by WHO

• TF: Trachomatous follicular inflammation is identified by the presence of more than five follicles, each larger than 0.5 mm, on the upper tarsus.
• TI: Trachomatous intense inflammation is characterized by thickening and obscuring of over 50% of large, deep tarsal vessels.
• TS: Trachomatous (conjunctival) cicatrization is marked by white lines, bands, or sheets of fibrosis in the tarsal conjunctiva, which appears glistening and fibrous with straight, angular, or feathered edges.
• TT: Trachomatous trichiasis is indicated by at least one in-turned eyelash or evidence of recent removal.
• CO: Corneal opacity that obscures part of the pupil margin, resulting in a visual acuity of less than 6/60.

Mnemonic: FISTO

The treatment for trachoma involves tetracycline and can be administered through two regimens:

• Topical Regimen: Involves the use of tetracycline 1% or erythromycin 1% ointment, applied four times a day (QID), with the ointment also applied at night.
• Systemic Regimen: Includes oral tetracycline or oral erythromycin given QID, oral doxycycline taken twice a day (BD), or a single dose of Azithromycin.

Adult Inclusion Conjunctivitis

Adult Inclusion Conjunctivitis is a type of acute follicular conjunctivitis characterized by mucopurulent discharge. It primarily affects sexually active young adults and is caused by serotypes D to K of  Chlamydia trachomatis  .

Sources and Transmission

• Urethritis in males and cervicitis in females are the main sources of infection for Adult Inclusion Conjunctivitis.
• The infection can spread to the eyes through contaminated fingers or, more commonly, through contaminated swimming pool water, leading to what is often referred to as 'swimming pool conjunctivitis.'

Ophthalmia Neonatorum

• Neonatal conjunctivitis, also known as Ophthalmia neonatorum, is a condition characterized by inflammation of the conjunctiva within the first month of life. This condition can be caused by various infectious agents, including Chlamydia, Gonococci, and other miscellaneous factors.
• Chlamydial conjunctivitis occurs when symptoms manifest between 5 to 14 days after birth, leading to acute mucopurulent conjunctivitis. If left untreated, ocular complications may arise, such as superior corneal pannus, conjunctival scarring, and corneal opacity. Additionally, systemic complications like otitis, rhinitis, and pneumonitis may occur. The treatment for chlamydial conjunctivitis involves systemic erythromycin and topical tetracycline.

Gonococcal Conjunctivitis

• Gonococcal conjunctivitis is a severe eye infection in newborns caused by the bacterium Neisseria gonorrhoeae. This infection is transmitted from the mother to the newborn during delivery.
• Symptoms of gonococcal conjunctivitis typically appear within 1 to 3 days after birth. The condition is characterized by hyper-acute purulent conjunctivitis, which may be accompanied by chemosis (swelling of the conjunctiva) and, in some cases, the formation of a membrane or pseudomembrane on the conjunctiva.
• Treatment for gonococcal conjunctivitis involves the use of antibiotics, with ceftriaxone or cefotaxime being the first-line options. Prompt treatment is crucial to prevent serious complications, including corneal perforation and vision loss.

Miscellaneous Conjunctivitis

• Chemical conjunctivitis occurs as a result of using 1% silver nitrate to prevent infective conjunctivitis, a practice known as the 'Crede's method.' It can also occur from the use of antibiotics to prevent gonococcal infection. Clinically, it presents with mild conjunctival hyperemia lasting no longer than 24 hours.
• Simple bacterial conjunctivitis is most commonly caused by Staphylococcus aureus. Herpes simplex conjunctivitis, caused by type-2 HSV due to maternal infection, presents as blepharoconjunctivitis and keratitis.
• Sticky eye is not a specific clinical condition but refers to the eye becoming sticky due to discharge.

Acute Hemorrhagic Conjunctivitis

Acute hemorrhagic conjunctivitis is a highly contagious eye infection caused by Enterovirus 70, a member of the Picornavirus group. The condition is self-limiting and typically resolves within 7 days. Patients usually experience bilateral, profuse watery discharge, and palpebral follicles are present.

• Enterovirus 70: This virus is the primary cause of acute hemorrhagic conjunctivitis. It belongs to the Picornavirus group and is known for its highly contagious nature.
• Adenovirus: Severe infections caused by adenoviruses can also lead to acute hemorrhagic conjunctivitis. Adenoviruses are a group of viruses that can cause a range of illnesses, including respiratory infections and conjunctivitis.
• Echo virus 34: This specific strain of the echo virus can cause acute hemorrhagic conjunctivitis. Echo viruses are similar to enteroviruses and can lead to various infections in humans.
• Coxsackie virus 24: Another member of the enterovirus family, Coxsackie virus 24 can also be responsible for acute hemorrhagic conjunctivitis. Coxsackie viruses are known to cause a variety of illnesses, including hand, foot, and mouth disease.

Treatment and Management: There is no specific antiviral treatment for acute hemorrhagic conjunctivitis. However, supportive care is often recommended to alleviate symptoms and promote recovery. This may include measures such as:

• Warm compresses: Applying warm compresses to the affected eyes can help relieve discomfort and reduce inflammation.
• Artificial tears: Lubricating eye drops can help soothe the eyes and relieve dryness caused by excessive tearing.
• Hygiene practices: Maintaining proper hygiene, such as frequent handwashing and avoiding touching the eyes, can help prevent the spread of the infection.

Causes of Subconjunctival Hemorrhage

• Trauma: Any injury to the eye or the surrounding area can cause blood vessels to rupture, leading to subconjunctival hemorrhage.
• Foreign body: The presence of a foreign object in the eye can irritate the conjunctiva and cause bleeding.
• Hypertension: High blood pressure can weaken blood vessels, making them more susceptible to rupture and causing subconjunctival hemorrhage.
• Bleeding diathesis: Conditions that affect blood clotting, such as hemophilia or von Willebrand disease, can lead to spontaneous bleeding in the conjunctiva.
• Pertussis: Also known as whooping cough, this bacterial infection can cause severe coughing fits that increase pressure in the blood vessels, leading to subconjunctival hemorrhage.
• Pneumococcal infection: Infections caused by the bacteria Streptococcus pneumoniae can lead to inflammation and bleeding in the conjunctiva.
• Viral infections: Certain viral infections can cause inflammation and damage to the blood vessels in the conjunctiva, leading to subconjunctival hemorrhage.

Allergic Conjunctivitis

A. Spring Catarrh or Vernal Keratoconjunctivitis (VKC)

• VKC is a recurrent and bilateral inflammation of the outer eye, primarily affecting children and young adults, with a higher prevalence in males.
• This condition is allergic in nature, involving IgE-mediated reactions. It is characterized by a papillary reaction without a follicular component.
• VKC typically begins after the age of 5 and usually resolves by puberty, although it can occasionally persist beyond 25 years of age.
• Symptoms often exacerbate in warm weather and include:

Intense ocular itching

• Lacrimation (tearing)
• Photophobia (sensitivity to light)
• Foreign body sensation
• Blurring of vision
• Thick mucus discharge (ropy)
• Rarely, ptosis (drooping eyelid)
• There are three main clinical types of VKC:
• Palpebral VKC: Characterized by papillary hypertrophy in the upper eyelid conjunctiva, with severe cases showing a cobblestone appearance due to flat-topped polygonal papillae.
• Limbal VKC: Involves hypertrophy of limbal papillae and the presence of Horner Trantas Spots, which are primarily composed of eosinophils.
• Mixed form: Features both limbal and palpebral conjunctiva involvement.
• Corneal changes associated with VKC may include:
• Punctate epitheliopathy: Characterized by microerosions.
• Macroerosions
• Plaque: Dried mucus over epithelial macroerosions.
• Subepithelial scarring: Typically appears as a ring.
• Pseudogerontoxon: Resembles Arcus senilis and is sometimes referred to as 'Cupid's bow.'
• Keratoconus may also be present.
• Treatment options for VKC include:
• Topical steroids, such as Fluorometholone.
• Sodium cromoglycate: 2% drops.
• Lodoxamide: 0.1% drops, which are considered superior to sodium cromoglycate.
• Acetylcysteine: 5% drops for treating plaques due to its mucolytic properties.
• Lamellar keratectomy: A procedure to remove plaques and accelerate re-epithelialization.

B. Phlyctenular Keratoconjunctivitis

Also referred to as Phlyctenulosis.

• This condition primarily impacts children.
• Etiology: It is triggered by an allergic reaction resulting from a non-specific delayed hypersensitivity to staphylococci, mycobacterial antigens, or other bacterial antigens present in the body.
• Clinical Feature: The hallmark is a small, pinkish-white lump near the limbus, surrounded by redness, known as a phlycten. A corneal phlycten can lead to a fascicular ulcer, which may subsequently progress to a ring ulcer.
• Differential Diagnosis (D/D). While the signs may appear similar, pain is characteristic of scleritis and episcleritis. These conditions exhibit deep congestion, whereas phlyctenular conjunctivitis is marked by superficial conjunctival congestion.
• A brief course of topical steroids is recommended to reduce inflammation.
• Any coexisting staphylococcal blepharitis should be treated.

Xerophthalmia

• Xerophthalmia is a significant cause of blindness in certain regions, especially among children.
• Vitamin A deficiency impacts the eyes by causing alterations in the conjunctiva, cornea, and retina, along with impairing the function of retinal rods and cones.
• This deficiency, known as xerophthalmia, results in epithelial xerosis instead of parenchymatous xerosis.
• A lack of dietary vitamin A can arise from either inadequate intake or poor absorption.

New WHO Classification of Xerophthalmia

• XN: Night blindness.
• X1A: Conjunctival xerosis.
• X1B: Bitot's spots.
• X2: (Description not provided).
• X3A: Keratomalacia affecting less than one-third of the corneal surface.
• X3B: Keratomalacia affecting more than one-third of the corneal surface.
• XS: Corneal scar due to xerophthalmia.
• XF: Xerophthalmic fundus.

Local Ocular Therapy

• Topical artificial tears
• In cases of keratomalacia, manage it as a bacterial corneal ulcer.

Vitamin A Therapy

• For infants under 1 year:
• Administer 1 lakh IU of Vitamin A via injection on days 0, 1, and 14.
• Also give 2 lakh IU orally on the same schedule.
• For infants less than 1 year, use half the dose.

Treatment of Underlying Conditions

• Address protein-energy malnutrition (PEM) and other nutritional disorders such as:
• Diarrhea, dehydration, and electrolyte imbalance.

WHO recommendations for Xerophthalmia prophylaxis:

• For infants under 6 months: Avoid giving 50,000 IU orally if breastfed.
• For 6-12 months (under 8 kg): Administer 1 lakh IU orally.
• For children over 1 year and under 6 years: Provide 2 lakh IU orally every 6 months.

Revised Schedule Under CSSM:

• First dose 1 lakh IU: at 9 months with measles vaccination.
• Second dose 2 lakh IU: at 18 months with DPT booster.
• Third dose 2 lakh IU: at 2 years of age.

Causes of Night Blindness:

• Vitamin A deficiency (Xerophthalmia).
• High myopia.
• Retinitis pigmentosa.
• Late-stage primary open-angle glaucoma.
• Congenital stationary night blindness.
• Oguchi's disease.
• Fundus albipunctatus.
• Favre-Goldmann syndrome.
• Choroideremia.
• Gyrate atrophy of the choroid.
• Generalized choroidal atrophy.

Causes of Parenchymatous Xerosis

• Cicatrizing Disorders: Conditions that cause scarring and contraction of tissues.
• Overexposure to the Atmosphere: Conditions that lead to excessive exposure of the eye surface to air.
• Cicatricial Pemphigoid: An autoimmune disorder leading to scarring of the conjunctiva.
• Stevens-Johnson Syndrome:. severe skin and mucous membrane condition causing conjunctival scarring.
• Trachoma:. bacterial infection causing scarring of the conjunctiva and cornea.
• Diphtheric Membranous Conjunctivitis:. severe form of conjunctivitis leading to membrane formation and scarring.
• Thermal and Chemical Burns: Injuries to the eye surface leading to scarring and contraction.
• Radiotherapy: Treatment causing damage and scarring of the conjunctival tissue.

Pre-Corneal Tear Film Layers

• Lipid Layer: Produced by Meibomian glands and glands of Zeis, it prevents tear evaporation.
• Aqueous Layer: Comprising 95% from main lacrimal glands and the rest from accessory glands of Krause and Wolfring, it provides the bulk of the tear film.
• Mucin Layer: Secreted by goblet cells and glands of Henle and Manz in the conjunctiva, it helps in tear film stability and spreading.

Keratoconjunctivitis Sicca (KCS)

• KCS is a dry eye condition primarily caused by a deficiency in the aqueous layer of the tear film.
• Types of KCS:
• Pure KCS: Involves only the lacrimal glands.
• Sjögren's Syndrome: KCS accompanied by xerostomia (dry mouth), hypergammaglobulinemia, rheumatoid arthritis (RA), and increased antinuclear antibodies (ANA). This is also known as Primary Sjögren's syndrome or Sicca syndrome. When associated with connective tissue disorders, it is referred to as Secondary Sjögren's syndrome.

Causes of KCS:

• Destruction of lacrimal glands due to tumors or inflammatory conditions.
• Dysfunction of Meibomian glands.
• Congenital or surgical absence of lacrimal glands.
• Blockage of the excretory ducts of the lacrimal glands.
• Destruction of goblet cells leading to conjunctival scarring.
• Neurological conditions such as Familial dysautonomia (Riley-Day Syndrome).

Symptoms of KCS: Include irritation, foreign body sensation, burning, and discharge of stingy mucus. Severe pain may occur due to filamentary keratitis.

On Examination

Tear Film:

• Marginal tear meniscus appears concave, small, and measures less than 1 mm.
• Increased presence of mucus strands and debris in the tear film.

Corneal Abnormalities:

• Punctate epitheliopathy characterized by small epithelial defects.
• Filamentary keratitis marked by the presence of filaments on the corneal surface.
• Mucous plaques observed on the cornea.

Investigations

Tear Film Break-Up Time:

• Normal: > 34 seconds
• Abnormal: < 10 seconds

Rose Bengal Staining: Staining pattern helps in identifying dead cells and mucus in KCS.

Schirmer's Test:

• Normal: > 15 mm
• Borderline: 5 mm to 10 mm
• Abnormal: < 5 mm

Lactoferrin Levels in Tears: Normal levels are around 327 mg/dL; levels under 90 mg/dL are considered pathological.

Tear Osmolality:. sensitive indicator of dry eye disease; normal levels are around 302 mosm/L. Values of 310-311 mosm/L indicate early dry eye, while 312 mosm/L is indicative of KCS.

Tear Substitutes:

• Types of Artificial Tears/Tear Substitutes:
• Polyvinyl alcohol and povidone-based products.
• Sodium hyaluronate (Healon) diluted 1:10 with sterile balanced salt solution.
• Hydroxypropyl methyl cellulose-based products.
• Gel tears made of high molecular weight cross-linked polymers of acrylic acid.
• Patient's own serum diluted with preservative-free normal saline.
• Mucolytic Agents: 5% Acetylcysteine drops to help break down mucus in the tear film.
• Topical Cyclosporine: An immunomodulatory treatment for dry eye caused by autoimmune conditions, promoting tear secretion.

Reduction of Tear Drainage: Punctal Occlusion

• Temporary: This is done by using heat to cauterize the puncta, which are the small openings in the eyelids where tears drain.
• Permanent: This involves the use of silicone plugs to block the puncta and reduce tear drainage.

Ocular Lesions of Measles

• Catarrhal conjunctivitis: Inflammation of the conjunctiva characterized by redness and discharge.
• Koplik's spots: These are small, bluish-white spots that appear on the conjunctiva and are indicative of measles infection.
• Corneal ulceration: This can occur due to xerophthalmia, a condition caused by vitamin A deficiency leading to dry eyes and corneal damage.
• Optic neuritis: Inflammation of the optic nerve, which can lead to vision loss and other visual disturbances.
• Retinitis: Inflammation of the retina, which can cause vision problems and is associated with measles infection.

Ocular Features of Mumps

• Acute Dacryocystoadenitis: Inflammation of the lacrimal gland, which can cause swelling and pain in the upper eyelid.
• Uveitis: Inflammation of the uvea, the middle layer of the eye, which can lead to pain, redness, and vision problems.
• Conjunctivitis: Inflammation of the conjunctiva, leading to redness, itching, and discharge from the eye.

Ocular Manifestations of Chickenpox

• This section discusses the eye-related issues that can occur with different viral infections.
• Varicella, known as Chickenpox, and Zoster, which includes Herpes Zoster Ophthalmicus (HZO), are caused by the same virus. However, there is no proof that HZO can be contracted from someone with Chickenpox.
• When pregnant women contract Chickenpox, it can result in several serious eye conditions in the newborn, including:
  • Horner's syndrome:. condition affecting the eye and facial muscles.
  • Optic nerve hypoplasia: Underdevelopment of the optic nerve, leading to vision problems.
  • Chorioretinitis: Inflammation of the choroid and retina, which can impair vision.
  • Cataract: Clouding of the eye's lens, which can cause blurred vision.

Degenerations of the Conjunctiva

A. Pinguecula

• Pinguecula is characterized by the appearance of yellow-white deposits on the bulbar conjunctiva, close to the limbus.
• Histological examination of pinguecula reveals degeneration of collagen fibers within the conjunctival stroma. Additionally, there is thinning of the epithelium and calcification.

B. Pterygium

• Pterygium involves the invasion of the cornea by a triangular sheet of fibrovascular tissue.
• This condition is triggered by exposure to dirt and ultraviolet rays.
• Stocker's line is observed as an iron deposition line in the cornea, resulting from chronic irritation caused by pterygium.
• The most reliable method to prevent recurrences of pterygium is surgical excision with autograft.
• Postoperative treatments such as beta-radiation, topical Thiotepa, or Mitomycin-C may also aid in preventing recurrence. Mitomycin-C can also be utilized before surgery.

C. Concretions

• Concretions are small deposits that are yellow-white in color. These deposits are found in the palpebral conjunctiva.

D. Retention Cyst

• A retention cyst is a type of lesion that is asymptomatic and characterized by a thin wall. It contains clear fluid and occurs due to the blockage of Krause's gland.

Other Types of Conjunctival Cysts

• Lymphangiectasis: This condition involves the dilation of lymph spaces.
• Implantation Cyst: This type of cyst occurs after squint surgery.
• Hydatid Cysts: These cysts are caused by the Hydatid disease.
• Cysticercosis Cysts: These cysts are associated with the parasitic infection caused by Taenia solium.
• Lymphangioma: This is a solitary, multilocular cyst that is formed by the abnormal growth of lymphatic vessels.