Ординатура / Офтальмология / Английские материалы / Comprehensive Ophthalmology_Khurana_2007

i. Capillary haemangioma (Fig. 14.40) is the most common variety which occurs at or shortly after birth, often grows rapidly and in many cases resolves spontaneously by the age of 7 years. These may be superficial and bright red in colour (strawberry naevus) or deep and bluish or violet in colour. They consist of proliferating capillaries and endothelial cells.

Treatment. Unless the tumour is very large it may be left untouched until the age of 7 years (as in many cases it resolves spontaneously). The treatment modalities include:

Excision: It is performed in small tumours.

Intralesional steroid (triamcinolone) injection is effective in small to medium size tumours.

Alternate day high dose steroid therapy regime is recommended for large diffuse tumours.

Superficial radiotherapy may also be given for

large tumours.

ii. Naevus flammeus (port wine stain). It may occur pari passu or more commonly as a part of SturgeWeber syndrome. It consists of dilated vascular channels and does not grow or regress like the capillary haemangioma.

Fig. 14.40. Capillary haemangioma.

Fig. 14.41. Neurofibroma upper eyelid.

MALIGNANT TUMOURS

1. Basal-cell carcinoma

It is the commonest malignant tumour of the lids (90%) usually seen in elderly people. It is locally malignant and involves most commonly lower lid (50%) followed by medial canthus (25%), upper lid (10-15%) and outer canthus (5-10%).

Clinical features. It may present in four forms:

Noduloulcerative basal cell carcinoma is the most common presentation. It starts as a small nodule which undergoes central ulceration with pearly rolled margins. The tumour grows by burrowing and destroying the tissues locally like a rodent and hence the name rodent ulcer (Fig. 14.42).

Other rare presentations include: non-ulcerated nodular form, sclerosing or morphea type and pigmented basal cell carcinoma.

Histological features. The most common pattern is solid basal cell carcinoma in which the dermis is invaded by irregular masses of basaloid cells with characteristic peripheral palisading appearance.

Fig. 14.42. Basal cell carcinoma lower eyelid.

Treatment

Surgery. Local surgical excision of the tumour along with a 3 mm surrounding area of normal skin with primary repair is the treatment of choice.

Radiotherapy and cryotherapy should be given only in inoperable cases for palliation.

2. Squamous cell carcinoma

It forms the second commonest malignant tumour of the lid. Its incidence (5%) is much less than the basal cell carcinoma. It commonly arises from the lid margin (mucocutaneous junction) in elderly patients. Affects upper and lower lids equally.

Clinial features. It may present in two forms: An ulcerated growth with elevated and indurated margins is the common presentation (Fig. 14.43). The second form, fungating or polypoid verrucous lesion without ulceration, is a rare presentation.

Metastasis. It metastatises in preauricular and submandibular lymph nodes.

Histological features. It is characterised by an irregular downward proliferation of epidermal cells into the dermis. In well-differentiated form, the malignant cells have a whorled arrangement forming epithelial pearls which may contain laminated keratin material in the centre.

Treatment on the lines of basal cell carcinoma.

3. Sebaceous gland carcinoma

(which may be mistaken for a chalazion). Which then grows to form a big growth (Fig. 14.44). Rarely, a diffuse tumour along the lid margin may be mistaken as chronic blepharitis. Surgical excision with reconstruction of the lids is the treatment of choice. Recurrences are common.

4. Malignant melanoma (melanocarcinoma)

It is a rare tumour of the lid (less than 1% of all eyelid lesions). It may arise from a pre-existing naevus, but usually arises de novo from the melanocytes present in the skin.

Clinically, it often appears as a flat or slightly elevated naevus which has variegated pigmentation and irregular borders. It may ulcerate and bleed.

Metastasis. The tumour spreads locally as well as to distant sites by lymphatics and blood stream.

Treatment. It is a radio-resistant tumour. Therefore, surgical excision with reconstruction of the lid is the treatment of choice.

Fig. 14.43. Squamous cell carcinoma of upper lid.

It is a rare tumour arising from the meibomian glands. Clinically, it usually presents initially as a nodule

Fig. 14.44. Meibomian gland carcinome lower eyelid.

APPLIED ANATOMY

The lacrimal apparatus comprises (1) Main lacrimal gland, (2)Accessory lacrimal glands, and (3) Lacrimal passages, which include: puncta, canaliculi, lacrimal sac and nasolacrimal duct (NLD) (Fig. 15.1).

Main lacrimal gland

It consists of an upper orbital and a lower palpebral part. (1) Orbital part is larger, about the size and shape of a small almond, and is situated in the fossa for lacrimal gland at the outer part of the orbital plate of frontal bone. It has got two surfaces — superior and inferior. The superior surface is convex and lies in contact with the bone. The inferior surface is concave and lies on the levator palpebrae superioris muscle. (2) Palpebral part is small and consists of only one or two lobules. It is situated upon the course of the ducts of orbital part from which it is separated by LPS muscle. Posteriorly, it is continuous with the orbital part.

Ducts of lacrimal gland. Some 10-12 ducts pass downward from the main gland to open in the lateral part of superior fornix. One or two ducts also open in the lateral part of inferior fornix.

Accessory lacrimal glands (Fig. 14.4)

1.Glands of Krause. These are microscopic glands lying beneath the palpebral conjunctiva between fornix and the edge of tarsus. These are about 42 in the upper fornix and 6-8 in the lower fornix.

2.Glands of Wolfring. These are present near the upper border of the superior tarsal plate and along the lower border of inferior tarsus.

Structure, blood supply and nerve supply

Structure. All lacrimal glands are serous acini, similar in structure to the salivary glands. Microscopically

Fig. 15.1. The lacrimal apparatus.

these consist of glandular tissue (acini and ducts), connective tissue and puncta.

Blood supply. Main lacrimal gland is supplied by lacrimal artery which is a branch of ophthalmic artery.

Nerve supply. (1) Sensory supply comes from lacrimal nerve, a branch of the ophthalmic division of the fifth nerve. (2) Sympathetic supply comes from the carotid plexus of the cervical sympathetic chain. (3) Secretomotor fibres are derived from the superior salivary nucleus.

Lacrimal passages

1.Lacrimal puncta. These are two small, rounded or oval openings on upper and lower lids, about 6 and 6.5 mm, respectively, temporal to the inner canthus. Each punctum is situated upon a slight elevation called lacrimal papilla which becomes prominent in old age. Normally the puncta dip into the lacus lacrimalis (collection of tear fluid in the inner canthus).

2.Lacrimal canaliculi. These join the puncta to the lacrimal sac. Each canaliculus has two parts: vertical (1-2 mm) and horizontal (6-8 mm) which lie at right angle to each other. The horizontal part converges towards inner canthus to open in the sac. The two canaliculi may open separately or may join to form common canaliculus which opens immediately into the outer wall of lacrimal sac. Afold of mucosa at this point forms the valve of Rosenmuller which prevents reflux of tears.

3.Lacrimal sac. It lies in the lacrimal fossa located in the anterior part of medial orbital wall. The lacrimal fossa is formed by lacrimal bone and frontal process of maxilla. It is bounded by anterior and posterior lacrimal crests. When distended, lacrimal sac is about

15mm in length and 5-6 mm in breadth. It has got three parts: fundus (portion above the opening of canaliculi), body (middle part) and the neck (lower small part which is narrow and continuous with the nasolacrimal duct).

4.Nasolacrimal duct (NLD). It extends from neck of the lacrimal sac to inferior meatus of the nose. It is about 15-18 mm long and lies in a bony canal formed by the maxilla and the inferior turbinate. Direction of the NLD is downwards, backwards and laterally. Externally its location is represented by a line joining inner canthus to the ala of nose. The upper end of the NLD is the narrowest part.

There are numerous membranous valves in the NLD, the most important is the valve of Hasner, which is present at the lower end of the duct and prevents reflux from the nose.

TEAR FILM

Structure of tear film

Wolff was the first to describe the detailed structure of the fluid covering the cornea and called it precorneal film. He described this film to consist of three layers, which from posterior to anterior are mucus layer, aqueous layer and lipid or oily layer (Fig. 15.2).

1.Mucus layer. It is the innermost and thinnest stratum of the tear film. It consists of mucin secreted by conjunctival goblet cells and glands of Manz. It converts the hydrophobic corneal surface into hydrophilic one.

2.Aqueous layer. The bulk of tear film is formed by this intermediate layer which consists of tears secreted by the main and accessory lacrimal glands. The tears mainly comprise of water and small quantities of solutes such as sodium chloride, sugar, urea and proteins. Therefore, it is alkaline and salty in taste. It also contains antibacterial substances like lysozyme, betalysin and lactoferrin.

3.Lipid or oily layer. This is the outermost layer of tear film formed at air-tear interface from the secretions of Meibomian, Zeis, and Moll glands. This layer prevents the overflow of tears, retards their evaporation and lubricates the eyelids as they slide over the surface of the globe.

Fig. 15.2. Structure of the tear film.

Functions of tear film

1.Keeps the cornea and conjunctiva moist.

2.It provides oxygen to the corneal epithelium.

3.Washes away debris and noxious irritants.

4.Prevents infection due to presence of antibacterial substances.

THE DRY EYE

The dry eye per se is not a disease entity, but a symptom complex occurring as a sequelae to deficiency or abnormalities of the tear film.

Secretion of tears

Tears are continuously secreted throughtout the day by accessory (basal secretion) and main (reflex secretion) lacrimal glands. Reflex secretion is in response to sensations from the cornea and conjunctiva, probably produced by evaporation and break-up of tear film. Hyperlacrimation occurs due to irritative sensations from the cornea and conjunctiva. Afferent pathway of this secretion is formed by fifth nerve and efferent by parasympathetic (secretomotor) supply of lacrimal gland.

Elimination of tears

Tears flow downward and medially across the surface of eyeball to reach the lower fornix and then via lacus lacrimalis in the inner canthus. From where they are drained by lacrimal passages into the nasal cavity (Fig. 15.3A). This is brought about by an active lacrimal pump mechanism constituted by fibres of the orbicularis (especially Horner’s muscle) which are inserted on the lacrimal sac. When the eye lids close during blink, contraction of these fibres distends the fundus of the sac, creates therein a negative pressure which syphons the tears through punctum and canaliculi into the sac (Fig. 15.3B). When the eyelids open, the Horner’s muscle relaxes, the lacrimal sac collapses and a positive pressure is created which forces the tears down the nasolacrimal duct into the nose (Fig. 15.3C). Therefore, in atonia of sac, tears are not drained through the lacrimal passages, in spite of anatomical patency; resulting in epiphora.

A B C

Fig. 15.3. Elimination of tears by lacrimal pump mechanism.

keratoconjunctivitis sicca. It is seen in conditions like congenital alacrimia, paralytic hyposecretion, primary and secondary Sjogren’s syndrome, Riley Day syndrome and idiopathic hyposecretion.

2.Mucin deficiency dry eye. It occurs when goblet cells are damaged, as in hypovitaminosis A (xerophthalmia) and conjunctival scarring diseases such as Stevens-Johnson syndrome, trachoma, chemical burns, radiations and ocular pemphigoid.

3.Lipid deficiency and abnormalities. Lipid deficiency is extremely rare. It has only been described in some cases of congenital anhydrotic ectodermal dysplasia along with absence of meibomian glands. However, lipid abnormalities are quite common in patients with chronic blepharitis and chronic meibomitis.

4.Impaired eyelid function. It is seen in patients with Bell’s palsy, exposure keratitis, dellen, symblepharon, pterygium, nocturnal lagophthalmos and ectropion.

5.Epitheliopathies. Owing to the intimate relationship between the corneal surface and tear film, alterations in corneal epithelium affect the stability of tear film.

Clinical features

Symptoms suggestive of dry eye include irritation, foreign body (sandy) sensation, feeling of dryness, itching, non-specific ocular discomfort and chronically sore eyes not responding to a variety of drops instilled earlier.

Signs of dry eye include: presence of stringy mucus and particulate matter in the tear film, lustureless ocular surface, conjunctival xerosis, reduced or absent marginal tear strip and corneal changes in the form of punctate epithelial erosions and filaments.

Tear film tests

These include tear film break-up time (BUT), Schirmer- I test, vital staining with Rose Bengal, tear levels of lysozyme and lactoferrin, tear osmolarity and

conjunctival impression cytology. Out of these BUT, Schirmer-I test and Rose Bengal staining are most important and when any two of these are positive, diagnosis of dry eye syndrome is confirmed.

1.Tear film break-up (BUT). It is the interval between a complete blink and appearance of first randomly distributed dry spot on the cornea. It is noted after instilling a drop of fluorescein and examining in a cobalt-blue light of a slit-lamp. BUT is an indicator of adequacy of mucin component of tears. Its normal values range from 15 to 35 seconds. Values less than

10seconds imply an unstable tear film.

2.Schirmer-I test. It measures total tear secretions. It is performed with the help of a 5 × 35 mm strip of Whatman-41 filter paper which is folded 5 mm from one end and kept in the lower fornix at the junction of lateral one-third and medial two-thirds. The patient is asked to look up and not to blink or close the eyes (Fig. 15.4). After 5 minutes wetting of the filter paper strip from the bent end is measured. Normal values of Schirmer-I test are more than 15 mm. Values of 5-10 mm are suggestive of moderate to mild keratoconjunctivitis sicca (KCS) and less than 5 mm of severe KCS.

3.Rose Bengal staining. It is a very useful test for detecting even mild cases of KCS. Depending upon the severity of KCS three staining patterns A, B and C have been described: ‘C’ pattern represents mild or early cases with fine punctate stains in the interpalpebral area; ‘B’ the moderate cases with extensive staining; and ‘A’ the severe cases with confluent staining of conjunctiva and cornea.

Fig. 15.4. Schirmer test.

Treatment

At present, there is no cure for dry eye. The following treatment modalities have been tried with variable results:

1.Supplementation with tear substitutes. Artificial tears remains the mainstay in the treatment of dry eye. These are available as drops, ointments and slowrelease inserts. Mostly available artificial tear drops contain either cellulose derivatives (e.g., 0.25 to 0.7% methyl cellulose and 0.3% hypromellose) or polyvinyl alcohol (1.4%).

2.Topical cyclosporine (0.05%, 0.1%) is reported to be very effective drug for dry eye in many recent studies. It helps by reducing the cell-mediated inflammation of the lacrimal tissue.

3.Mucolytics, such as 5 percent acetylcystine used

4times a day help by dispersing the mucus threads and decreasing tear viscosity.

4.Topical retinoids have recently been reported to be useful in reversing the cellular changes (squamous metaplasia) occurring in the conjunctiva of dry eye patients.

5.Preservation of existing tears by reducing evaporation and decreasing drainage.

Evaporation can be reduced by decreasing room

temperature, use of moist chambers and protective glasses.

Punctal occlusion to decrease drainage can be carried out by collagen implants, cynoacrylate tissue adhesives, electrocauterisation, argon laser occlusion and surgical occlusion to decrease the drainage of tears in patients with very severe dry eye.

SJOGREN’S SYNDROME

It is an autoimmune chronic inflammatory disease with multi-system involvement. It typically occurs in women between 40 and 50 years of age. Its main feature is an aqueous deficiency dry eye — the keratoconjunctivitis sicca (KCS). In primary Sjogren’s syndrome patients present with sicca complex– a combination of KCS and xerostomia (dryness of mouth). In secondary Sjogren’s syndrome dry eye and/or dry mouth are associated with an autoimmune disease, commonly rheumatoid arthritis. Its pathological features include focal accumulation and infiltration by lymphocytes and plasma cells with destruction of lacrimal and salivary glandular tissue.

THE WATERING EYE

It is characterised by overflow of tears from the conjunctival sac. The condition may occur either due to excessive secretion of tears (hyperlacrimation) or may result from obstruction to the outflow of normally secreted tears (epiphora).

Etiology

(A) Causes of hyperlacrimation

1.Primary hyperlacrimation. It is a rare condition which occurs due to direct stimulation of the lacrimal gland. It may occur in early stages of lacrimal gland tumours and cysts and due to the effect of strong parasympathomimetic drugs.

2.Reflex hyperlacrimation. It results from stimulation of sensory branches of fifth nerve due to irritation of cornea or conjunctiva. It may occur in multitude of conditions which include:

Affections of the lids: Stye, hordeolum internum,

acute meibomitis, trichiasis, concretions and entropion.

Affections of the conjunctiva: Conjunctivits which may be infective, allergic, toxic, irritative or traumatic.

Affections of the cornea: These include, corneal abrasions, corneal ulcers and non-ulcerative keratitis.

Affections of the sclera: Episcleritis and scleritis.

Affections of uveal tissue: Iritis, cyclitis, iridocyclitis.

Acute glaucomas.

Endophthalmitis and panophthalmitis.

Orbital cellulitis.

3. Central lacrimation (psychical lacrimation). The exact area concerned with central lacrimation is still not known. It is seen in emotional states, voluntary lacrimation and hysterical lacrimation.

(B) Causes of epiphora

Inadequate drainage of tears may occur due to physiological or anatomical (mechanical) causes.

I Physiological cause is ‘lacrimal pump’ failure due to lower lid laxity or weakness of orbicularis muscle.

II Mechanical obstruction in lacrimal passages may lie at the level of punctum, canaliculus, lacrimal sac or nasolacrimal duct.

1.Punctal causes include:

Eversion of lower punctum: It is commonly seen in old age due to laxity of the lids. It may also occur following chronic conjunctivitis, chronic blepharitis and due to any cause of ectropion.

Punctal obstruction: There may be congenital absence of puncta or cicatricial closure following injuries, burns or infections. Rarely a small foreign body, concretion or cilia may also block the punctum. Prolonged use of drugs like idoxuridine and pilocarpine is also associated with punctal stenosis.

2.Causes in the canaliculi. Canalicular obstruction may be congenital or acquired due to foreign body, trauma, strictures and canaliculitis. Commonest cause of canaliculitis is actinomyces.

3.Causes in the lacrimal sac. These include congenital mucous membrane folds, traumatic strictures, dacryocystitis, specific infections like tuberculosis and syphilis, dacryolithiasis, tumours and atonia of the sac.

4.Causes in the nasolacrimal duct. Congenital lesions include non-canalization, partial canalization or imperforated membranous valves. Acquired causes of obstruction are traumatic strictures, inflammatory strictures, tumours and diseases of the surrounding bones.

Clinical evaluation of a case of ‘Watering eye’

1.Ocular examination with diffuse illumination using magnification should be carried to rule out any cause of reflex hypersecretion located in lids, conjunctiva, cornea, sclera, anterior chamber, uveal tract and so on. This examination should also exclude punctal causes of epiphora and any swelling in the sac area.

2.Regurgitation test. A steady pressure with index finger is applied over the lacrimal sac area above the medial palpebral ligament. Reflux of mucopurulent discharge indicates chronic dacryocystitis with obstruction at lower end of the sac or the nasolacrimal duct.

3.Fluorescein dye disappearance test (FDDT). In this test 2 drops of fluorescein dry eye are instilled in both the conjunctival sacs and observations are made after 2 minutes. Normally, no dye is seen in the conjunctival sac. A prolonged retention of dye in conjunctival sac indicates inadequate drainage which may be due to atonia of sac or mechanical obstruction.

4. Lacrimal syringing test. It is performed after topical anaesthesia with 4 percent xylocaine (Fig. 15.5). Normal saline is pushed into the lacrimal sac from lower punctum with the help of a syringe and lacrimal cannula.

Fig. 15.5. Technique of lacrimal syringing.

A free passage of saline through lacrimal passages into the nose rules out any mechanical obstruction.

In the presence of partial obstruction, saline passes with considerable pressure on the syringe.

In the presence of obstruction no fluid passes into nose and it may reflux through same punctum (indicating obstruction in the same or common canaliculus) or through opposite punctum (indicating obstruction in the lower sac or

nasolacrimal duct).

5. Jones dye tests. These are performed when partial obstruction is suspected. Jones dye tests are of no value in the presence of total obstruction.

i.Jones primary test (Jones test I). It is performed to differentiate between watering due to partial obstruction of the lacrimal passages from that due to primary hypersecretion of tears. Two drops of 2 percent fluorescein dye are instilled in the conjunctival sac and a cotton bud dipped in 1 percent xylocaine is placed in the inferior meatus

at the opening of nasolacrimal duct. After 5 minutes the cotton bud is removed and inspected. A dye-stained cotton bud indicates adequate drainage through the lacrimal passages and the cause of watering is primary hypersecretion (further investigations should aim at finding the cause of primary hypersecretion). While the unstained cotton bud (negative test) indicates either a partial obstruction or failure of lacrimal pump mechanism. To differentiate between these conditions, Jones dye test-II is performed.

ii. Jones secondary test (Jones test II). When primary test is negative, the cotton bud is again placed in the inferior meatus and lacrimal syringing is performed. A positive test suggests that dye was present in the sac but could not reach the nose due to partial obstruction. A negative test indicates presence of lacrimal pump failure.

6. Dacryocystography. It is valuable in patients with mechanical obstruction. It tells the exact site, nature and extent of block (Fig. 15.6). In addition, it also gives information about mucosa of the sac, presence of any fistulae, diverticulae, stone, or tumour in the sac.

To perform it a radiopaque material such as lipiodol, pentopaque, dianosil or condray-280 is pushed in the sac with the help of a lacrimal cannula and X-rays are taken after 5 minutes and 30 minutes to visualize the entire passage. For better anatomical visualization the

Fig. 15.6. Normal dacryocystogram.

modified technique known as substraction macrodacryocystography with canalicular catheterisation should be preferred.

7. Radionucleotide dacryocystography (lacrimal scintillography). It is a non-invasive technique to assess the functional efficiency of lacrimal drainage apparatus. A radioactive tracer (sulphur colloid or technitium) is instilled into the conjunctival sac and its passage through the lacrimal drainage system is visualised with anAnger gamma camera (Fig. 15.7).

Fig. 15.7. Lacrimal scintillography showing: A, normal lacrimal excretory system on right side; B, obstruction at the junction of lacrimal sac and nasolacrimal on left side.

DACRYOCYSTITIS

Inflammation of the lacrimal sac is not an uncommon condition. It may occur in two forms: congenital and adult dacryocystitis.

CONGENITAL DACRYOCYSTITIS

It is an inflammation of the lacrimal sac occurring in newborn infants; and thus also known as dacryocystitis neonatorum.

Etiology

It follows stasis of secretions in the lacrimal sac due to congenital blockage in the nasolacrimal duct. It is of very common occurrence.As many as 30 percent of newborn infants are believed to have closure of nasolacrimal duct at birth; mostly due to ‘membranous occlusion’ at its lower end, near the valve of Hasner.

Other causes of congenital NLD block are: presence of epithelial debris, membranous occlusion at its upper end near lacrimal sac, complete noncanalisation and rarely bony occlusion. Common bacteria associated with congenital dacryocystitis are staphylococci, pneumococci and streptococci.

Clinical picture

Congenital dacryocystitis usually presents as a mild grade chronic inflammation. It is characterised by:

1.Epiphora, usually developing after seven days of birth. It is followed by copious mucopurulent discharge from the eyes.

2.Regurgitation test is usually positive, i.e., when pressure is applied over the lacrimal sac area, purulent discharge regurgitates from the lower punctum.

3.Swelling on the sac area may appear eventually.

Differential diagnosis

Congenital dacryocystitis needs to be differentiated from other causes of watering in early childhood especially ophthalmia neonatorum and congenital glaucoma.

Complications

When not treated in time it may be complicated by recurrent conjunctivitis, acute on chronic dacryocystitis, lacrimal abscess and fistulae formation.

Treatment

It depends upon the age at which the child is brought. The treatment modalities employed are as follows:

1.Massage over the lacrimal sac area and topical antibiotics constitute the treatment of congenital NLD block, up to 6-8 weeks of age. Massage increases the hydrostatic pressure in the sac and helps to open up the membranous occlusions. It should be carried out at least 4 times a day to be followed by instillation of antibiotic drops. This conservative treatment cures obstruction in about 90 percent of the infants.

2.Lacrimal syringing (irrigation) with normal saline and antibiotic solution. It should be added to the conservative treatment if the condition is not cured up to the age of 2 months. Lacrimal irrigation helps to open the membranous occlusion by exerting hydraulic pressure. Syringing may be carried out once or twice a week.

3.Probing of NLD with Bowman’s probe. It should be performed, in case the condition is not cured by the age of 3-4 months. Some surgeons prefer to wait till the age of 6 months. It is usually performed under general anaesthesia. While performing probing, care must be taken not to injure the canaliculus. In most instances a single