What is the Difference Between Anterior and Posterior Blepharitis

Blepharitis is a condition that causes inflammation in the eyelid margin. It can be classified into two types: anterior and posterior blepharitis. Blepharitis results in ocular discomfort and irritation. Though this condition is not sight-threatening, blepharitis can lead to permanent changes in the eyelid margin or vision loss.

The key difference between anterior and posterior blepharitis is their anatomical location. Anterior blepharitis affects the eyelid skin, the base of the eyelashes, and the eyelash follicles, while posterior blepharitis affects the meibomian glands and gland orifices.

CONTENTS

1. Overview and Key Difference
2. What is Anterior Blepharitis
3. What is Posterior Blepharitis
4. Similarities – Anterior and Posterior Blepharitis
5. Anterior vs Posterior Blepharitis in Tabular Form
6. Summary – Anterior and Posterior Blepharitis
7. FAQ – Anterior and Posterior Blepharitis

What is Anterior Blepharitis?

Anterior blepharitis is a type of blepharitis that affects the outside of the eyelid where the eyelashes attach. It is further divided into three types: seborrheic, ulcerative, and Demodex. Seborrheic blepharitis is caused by dandruff. In this condition, the eyelids become red and produce waxy scales that build up on the eyelashes, which triggers eye itching. Ulcerative blepharitis is caused by bacteria and usually affects children. It causes hard crusts to form around the eyelashes, which become matted during sleep. This makes it difficult to open the eyes in the morning.

Demodex blepharitis is caused by an infestation of Demodex mites. The symptoms of Demodex blepharitis include burning, itchy, scratchy, dry eyes, aching, fatigued, heavy, sore eyes, light sensitivity, and blurred vision.

Anterior blepharitis can be diagnosed through eye examinations and cultures of eyelid margins. Furthermore, treatment options for anterior blepharitis include controlling dandruff, topical antibiotics such as creams like bacitracin or erythromycin that can be applied to the eyelid margin for 2 to 8 weeks, and hypochlorous-based acid for Demodex mites or topical medicines with a low concentration of tea tree oil.

What is Posterior Blepharitis?

Posterior blepharitis is a type of blepharitis that develops when the oil glands in the inner eyelid allow bacteria to grow. These glands are known as meibomian glands and secrete an oil that gets mixed with tears. Oil is important in preventing tear film evaporation. The typical symptoms of this condition include red, burning eyes,  dry eyes, and fluctuations in vision. Posterior blepharitis also occurs as a result of skin conditions such as rosacea, acne, and scalp dandruff.

Posterior blepharitis can be diagnosed by examining the posterior eyelid margin. The treatment options for posterior blepharitis may include eyelid hygiene and taking oral tetracyclines. and macrolide antibiotics.

Similarities Between Anterior and Posterior Blepharitis

1. Anterior and posterior blepharitis are two types of blepharitis according to anatomic location.
2. Both types result in discomfort and irritation in the eye.
3. Both types are not sight-threatening but can lead to permanent changes in the eyelid margin or vision loss from corneal neovascularization, superficial keratopathy, and ulceration.
4. Both types can be diagnosed through eye examination.
5. They can be treated through topical and oral medications that reduce eye inflammation.

Difference Between Anterior and Posterior Blepharitis

Definition

1. Anterior blepharitis develops at the outside front edge of the eyelid where the eyelashes attach.
2. Posterior blepharitis develops at the inner edge of the eyelid that touches the eyeball.

Commonness

1. Anterior blepharitis is less common.
2. Posterior blepharitis is more common.

Causes

1. Anterior blepharitis is commonly caused by bacteria (staphylococcal) or dandruff on the scalp and eyebrows.
2. Posterior blepharitis can occur when the glands of the eyelids irregularly produce oil that allows bacterial growth and skin conditions, such as rosacea and scalp dandruff.

Symptoms

1. Symptoms of anterior blepharitis include eyelids becoming red and producing waxy scales that build up on the eyelashes, eye itching, hard crusts forming around the eyelashes which become matted during sleep, difficulty opening the eyes in the morning, burning, itchy, scratchy, dry eyes, aching, fatigued, heavy, sore eyes, light sensitivity, and blurred vision.
2. Symptoms of posterior blepharitis include red, burning eyes, or dry eyes and fluctuations in vision.

Diagnosis

1. Anterior blepharitis can be diagnosed through medical history, eye examination, and cultures of the eyelid margins.
2. Posterior blepharitis can be diagnosed through diagnosed by examining the posterior eyelid margin and symptom evaluation.

Treatment

1. Treatments for anterior blepharitis may include controlling dandruff through antidandruff shampoos, applying topical antibiotics such as creams like bacitracin or erythromycin in the affected area for 2 to 8 weeks, using low-concentration tea tree oil or hypochlorous acid-based solutions to target Demodex mites.
2. Treatments for posterior blepharitis may include eyelid hygiene, oral tetracyclines, macrolide antibiotics, steroid eye drops, ointments to reduce redness and swelling, and artificial tears to help keep eyes moist.

The following table summarizes the difference between anterior and posterior blepharitis.

Summary – Anterior vs Posterior Blepharitis

Blepharitis is a condition that causes the inflammation of the eyelids. In this condition, eyes become red, itchy, and irritated, with dandruff-like scales that form on the eyelashes. There are two types of blepharitis as anterior and posterior. Anterior blepharitis affects the outside front of the eyelid where the eyelashes attach. Posterior blepharitis, on the other hand, affects the meibomian glands, which are in the inner eyelid. This is the key difference between anterior and posterior blepharitis.

FAQ: Anterior and Posterior Blepharitis

1. How to fix a swollen eyelid?

• A swollen eyelid can be relieved by a cool compress over the eye. This may help relieve swelling in the eyelid, while a saline rinse can help clear away crust and discharge. If the condition is not improved, a doctor can recommend treatment based on the cause.

2. What is the most common cause of anterior blepharitis?

• Anterior blepharitis is caused by bacteria (Staphylococcus), dandruff of the scalp, and eyebrows or Demodex mites.

3. How does it treat anterior blepharitis?

• Treatment options for anterior blepharitis involve managing dandruff, applying topical antibiotic creams such as bacitracin or erythromycin to the eyelid margin for 2 to 8 weeks, and using low-concentration tea tree oil or hypochlorous acid-based solutions to target Demodex mites.

4. How does it treat posterior blepharitis?

• Posterior blepharitis can be treated by taking oral tetracyclines and macrolide antibiotics, steroid eye drops and ointments to reduce redness and swelling, and artificial tears to help keep eyes moist.

5. What vitamin deficiency causes blepharitis?

• Vitamins are organic chemical compounds that help optimal bodily function. Some research links blepharitis to not having enough vitamin D in the diet. Vitamin D deficiency may also be linked to an increased risk of MGD (meibomian gland dysfunction), which can lead to posterior blepharitis.

Reference:

1. “Blepharitis.” AOA.Org.
2. “Blepharitis.” DermNet®.

Image Courtesy:

1. “Lid scrubs are essential for blepharitis management” By Community Eye Health (CC BY-NC 2.0) via Flickr
2. “Blepharitis – folliculitis stage” By Docjmrmd – Own work (CC BY-SA 4.0) via Commons Wikimedia

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