CORNEAL DISORDERS
DRY EYE
- The continuous production and drainage of tears are vital for maintaining the eye’s health. Tears serve to keep the eye moist, facilitate wound healing, and safeguard against infections. Additionally, the tear film smoothens the cornea’s surface, enhancing visual clarity and giving it a polished appearance.
- Dry eye is a prevalent condition, particularly among women following menopause.
- Causes:
- Tears are predominantly produced by the lacrimal gland located in the upper outer part of the eye socket. Tears exit the eye through either evaporation or drainage. The tear drainage system extends from the inner corner of both eyelids and drains into the nose. Dry eyes commonly occur with age due to reduced tear production by the lacrimal gland. Other causes may include eyelid problems such as blepharitis, resulting in poor tear quality. Dry eye can also arise in dry climates and due to certain medications like antihistamines, nasal decongestants, tranquillisers, and antidepressants. Individuals with connective tissue diseases such as rheumatoid arthritis may develop dry eye. Additionally, dry eye can be a symptom of Sjögren’s syndrome, an autoimmune disorder affecting the body’s lubricating glands, leading to dry eyes and dry mouth.
SIGNS & SYMPTOMS
Patients experiencing dry eye commonly report persistent discomfort, often characterized by a burning or gritty sensation. Some describe it as feeling scratchy or sandy, as if something is lodged in the eye. Additional symptoms may include stinging, stringy discharge, a sense of heaviness, blurred vision, or excessive watering, particularly if tear quality is poor. The eyes may appear red and lose their shiny appearance, and stringy mucus strands and filaments may be noticeable. Reduction in the tear film on the lower eyelid and rapid tear break-up time may also occur.
TREATMENT
The primary treatment for dry eye typically involves frequent use of lubricating drops or artificial tears, readily available over the counter. Sterile ointments may be used at night, although they can initially cause blurry vision in the morning. Patients may have varying preferences for drops and require different frequencies of administration, ranging from once daily to every 15 minutes. While drops are usually cheaper than prescription charges, they are available on prescription if needed. Additional measures for relief may include using humidifiers, wearing wrap-around glasses outdoors, and avoiding windy and dry conditions. In severe cases, temporary or permanent closure of tear drains may be beneficial. Some individuals utilize swimming goggle-type protection to reduce evaporation. Severe dry eye patients may require punctal plugs for tear drainage occlusion. Recent findings suggest that cyclosporine (0.05%) drops can enhance tear formation, while autologous serum drops aid in healing micro epithelial defects. Patients undergoing treatment should receive proper counseling before considering cataract surgery.
CORNEAL ULCER
- A corneal ulcer develops when the surface of the cornea is compromised or damaged. Ulcers may be sterile (without infecting organisms) or infectious. The term “infiltrate” is often used interchangeably with ulcer, referring to an accumulation of inflammatory cells in an abnormal area of the body.
- Differentiating between infectious and non-infectious ulcers is crucial for determining the appropriate course of treatment. Bacterial ulcers are typically extremely painful and are associated with a break in the epithelium, the cornea’s superficial layer. In severe cases, the inflammatory response may involve the anterior chamber along with the cornea. Certain bacteria, such as Pseudomonas, can cause rapid and severe damage, potentially leading to blindness within 24-48 hours if left untreated.
- In contrast, sterile infiltrates cause minimal or no pain and are often found near the cornea’s peripheral edge. They may not necessarily involve a break in the corneal epithelial layer.
- Various factors can cause corneal ulcers. Many patients sustain corneal epithelial injuries while working in fields, leading to fungal corneal ulcers due to vegetative foreign bodies. Contact lens wearers, especially soft lens wearers, are at increased risk of ulcers if they do not adhere to strict cleaning, handling, and disinfection regimens for their lenses and cases. Soft contact lenses, with their high water content, can easily harbor bacteria and infecting organisms if not properly cared for. Pseudomonas is a common cause of corneal ulcers in contact lens wearers.
- Bacterial ulcers may occur in individuals with conditions compromising the corneal surface, creating an opportunity for organisms to infect the cornea. Fungal corneal ulcers require early diagnosis and prompt treatment, as medications used to treat them may not penetrate deeply into the eye. Patients with severely dry eyes, difficulty blinking, or inability to care for themselves are also at risk. Other causes of ulcers include herpes simplex viral infections, inflammatory diseases, corneal abrasions or injuries, and systemic diseases.
SIGNS AND SYMPTOMS
- The symptoms of corneal ulcers vary depending on whether they are infectious or sterile and the aggressiveness of the infecting organism. Common symptoms include red eye, tearing, discharge, and light sensitivity. In some cases, there may be severe pain, while in others, a white spot on the cornea may be visible, although it may not always be apparent to the naked eye.
DETECTION AND DIAGNOSIS
Corneal ulcers are diagnosed with a careful examination using a slit lamp microscope. Special types of eye drops containing dye such as fluorescein may be instilled to highlight the ulcer, making it easier to detect. If an infectious organism is suspected, the doctor performs corneal scraping and may order a culture. After numbing the eye with topical eye drops, cells are gently scraped from the corneal surface and tested to determine the infecting organism.
TREATMENT
The treatment approach varies depending on whether the corneal ulcer is sterile or infectious. Bacterial ulcers necessitate aggressive treatment, often involving antibacterial eye drops administered every 15 minutes. Steroid medications are avoided in cases of infectious ulcers. Severe ulcers may require hospitalization for intravenous antibiotics and continuous therapy. Sterile ulcers are typically managed by reducing the eye’s inflammatory response with steroid drops, anti-inflammatory drops, and antibiotics. Sterile ulcers at risk of or causing corneal perforations may be treated with corneal glue. Large or infective corneal perforations may require Tectonic Penetrating Keratoplasty.