Lacrimal System Disorders - An Overview

Introduction

The eye is one of the most important organs of the human body. Protection of the eye and other ocular structures is necessary for proper vision. Tears are one of the most necessary parts of the ocular system. It not only has emotional values but also protects the eye from foreign substances. Tears are produced by the lacrimal gland. But, with the help of other structures, tears are distributed in the ocular system. Together, these structures form the lacrimal apparatus.

What Is Lacrimal Apparetus?

The lacrimal apparatus or tear system is an organ system associated with tear production. The lacrimal apparatus consists of the lacrimal gland and nasolacrimal duct. The lacrimal gland is a multilobular tear-shaped gland. It is located just above the eye within the frontal bone in a position named the lacrimal fossa. The levator palpebrae superioris tendon bisect this gland and form two lobes. Acinar, ductal, and myoepithelial are different cell types that are present within this gland. Acinar cells consist of 80 percent of the cellular population of the lacrimal gland. These cells produce several types of proteins. Ductal cells form networks of ducts within the lacrimal gland. These cells secret water and electrolytes and modify the secretion produced by acinar cells. Myoepithelial cells contain multiple processes that help the secretion move out of the lacrimal gland. The secreted fluid from both glands reaches the conjunctival fornix via the excretory duct.

The function of the lacrimal duct is to transmit the tear from the eyes to the nasal cavity. After reaching the upper eyelid the tear film is distributed throughout the eye. This tear is collected from both the upper and lower eyelid by the lacrimal punctum. After entering into the lacrimal punctum the tear travels through the vertical canaliculus for 2 millimeters. After this, the vertical canaliculus forms the ampulla. From here both the canaliculi make a 90-degree turn and enter into the lacrimal sac. The lacrimal duct is extended from the lacrimal sac in a downward direction and drains into the nose. The disorder of the lacrimal apparatus can be divided into; disorder of the lacrimal gland, and disorder of the lacrimal sac. Dry eye disease is a disorder of the lacrimal system that affects tear production.

What Are the Disorders of Lacrimal Gland?

The most common disorder of the lacrimal gland is inflammation of the lacrimal gland. Inflammation of the lacrimal gland is known as dacryoadenitis. The causative factors for these conditions are:

1. Infections: This is mainly caused by bacteria like Pneumococci species, Staphylococcus aureus, and Streptococcus pneumoniae. Other than this corynebacterium species, Histoplasma species, Blastomyces species, and Haemophilus species are also responsible for this. Viral infections like mumps and measles are also responsible for this condition.

2. Auto-immune Disorders: Sjögren's syndrome is one of the most autoimmune diseases responsible for inflammation of the lacrimal gland. In this condition, patients develop autoantibodies directed against organ and non-organ-specific autoantigens. Ribonucleoproteins Ro/SSA and La/SSB are the most common autoantibodies found in this condition. Also, autoantibodies against alpha-fodrin and M3 muscarinic receptors are present in this disease. These antibodies act against the lacrimal gland and are responsible for T-lymphocyte infiltration. Also, the expression of pro-inflammatory mediators like cytokines is associated with Sjögren's syndrome.

Sarcoidosis is another chronic inflammatory condition that is associated with inflammation of the lacrimal gland. In this condition, the over-activation of immune cells is responsible for the formation of granulomas. This is a T-lymphocyte-driven disorder characterized by the infiltration of T- lymphocytes inside the lacrimal gland. Graft-versus-host disease is also associated with the inflammation of the lacrimal gland. This condition develops after organ transplantation, bone transplantation, and unirradiated blood. In this condition, the graft's immune cells recognize the host cells as foreign cells and destroy them by attacking them. Other than this, systemic disorders like hepatitis C (infection caused by the hepatitis C virus), severe diabetes, thyroid disorders, and acquired immunodeficiency syndrome are responsible for this condition.

1. Hormonal Imbalance: Hormones play a crucial role in the regulation of inflammation. Androgen has anti-inflammatory properties. On the other hand, hormones like estrogen and prolactin are associated with the increased inflammatory response. As a result, conditions like androgen deficiency are associated with increased destruction of cells of the lacrimal gland.

2. Neural Dysfunction: The lacrimal gland is directly influenced by the action of parasympathetic and sympathetic nerves. Destruction of nerve fibers or disease affecting neurotransmission may affect the functioning of the lacrimal gland. Neural degeneration with aging may also be associated with disorders of the lacrimal gland.

A. Symptoms of Lacrimal Gland Disorder:

The symptoms of lacrimal gland disorder are the following:

1. Presence of swelling in the upper outside corner of the eye.

2. Pain during eye movement.

3. Difficulty in opening the eye.

4. Redness of the eye.

5. Presence of double vision.

6. Drooping of the upper eyelid.

B. Treatment Options:

The treatment option for such a condition depends upon the causative factors responsible for such a condition. In case of infectious conditions, systemic antibiotics or antiviral drugs can be prescribed. For autoimmune conditions, systemic steroid therapy can be used.

What Is the Disorder of Lacrimal Sac?

Inflammation of the nasolacrimal sac is known as dacryocystitis. This inflammation causes stagnation of the tear in the lacrimal duct and produces dryness of the eye. This is caused by several conditions. The conditions are:

1. Acute infection of the lacrimal duct is one of the main reasons for the inflammation of the lacrimal sac. This infection is mainly caused by pathogens like Staphylococcus spices, Streptococcus species, Haemophilus influenza, and Pseudomonas aeruginosa.

2. The presence of the stone inside of the sack (dacryoliths) also may be associated with the accumulation of fluid and inflammation of the duct.

3. Endosinus or endonasal surgical procedures often cause trauma to the lacrimal sac and cause inflammation.

4. Different drugs such as Fluorouracil, Pilocarpine, Dorzolamide, and Docetaxel are associated with inflammation of the lacrimal sac.

5. Benign and malignant tumors of the lacrimal duct are also responsible for the production of obstruction.

6. In cases of babies, amniotic fluid sometimes enters the lacrimal sac. This fluid often gets infected and causes inflammation of the lacrimal sac.

A. Symptoms of Disorders of Lacrimal Sac:

The symptoms are:

1. Swelling and redness in the inner corner of the eye.

2. Pain in the inner corner of the eye.

3. Purulent discharge often comes out of the superior and inferior puncta.

4. Excessive tearing can be observed.

B. Treatment Options:

The treatment options depend open the causative factor of this condition. Antibiotic therapy is advised in case of the presence of any infection. Warm compression has often proved to be beneficial to reduce the symptoms. Minimally invasive lacrimal duct surgery can be done to remove stones and obstructions. In the case of the neonates' dacryocystorhinostomy (creation of a new path for the lacrimal duct) can also be done.

What Is Dry Eye Disorder?

Dry eye disease is a condition characterized by tear deficiency in the eye. The deficiency may be caused by decreased production of tears or may be caused by excessive evaporation. This condition leads to visual problems and irritation in the eye. This condition can be a single entity or may be caused by other factors like diseases. Several factors are involved in this condition. Factors associated with decreased production of the tears are:

1. Autoimmune disorders like Sjögren's syndrome, rheumatoid arthritis, and sarcoidosis.

2. Drugs like anti-cholinergic drugs, beta-blockers, diuretics, and antiviral drugs.

Factors that are associated with increased evaporation or destabilization of the tear film are:

1. Staphylococcal and Moraxella infection.

2. Bell’s palsy.

3. Seborrhoeic dermatitis.

4. Meibomian gland dysfunction.

A. Symptoms of Dry Eye Disease:

The symptoms are:

1. Redness of the eye.

2. Presence of the foreign body in the eye.

3. Itching sensation and difficulty in eye-opening.

4. Diminished vision and photophobia.

5. Symptoms are worse in the morning; eyelids are stuck after waking.

B. Treatment:

The primary treatment for this condition is to ask the patient to maintain eyelid hygiene. The patient is asked to clean the eyelid with water and a clean cloth. Warm compression for 5 to 10 minutes a few times a day can be helpful. Massaging the lid margin and scrubbing with moist cloth help to clean debris. To alleviate dry eye conditions, artificial eye drops are given. Topical antibiotics such as Bacitracin, Erythromycin, Azithromycin, or Tobramycin can be prescribed. The topical application of steroid ointments can help reduce inflammation.

Conclusion

The lacrimal system is an integral part of ocular functioning. An adequate amount of production of tears is essential in maintaining the normal function of the eye. Various infections and autoimmune conditions are the main factors responsible for the development of lacrimal system disorder. Early diagnosis and proper medications are necessary to treat such condition