[Local Medical]Dry eye syndrome can cause blindness if the cornea is scarred

Written by ◆ Yang Qianni and compiled by ◆ Liang Yingxiu

Modern people are prone to dry eyes and discomfort due to staring at computers for long periods of time, whether they are driving long distances back home, staying up late to surf the Internet, watching TV or even playing mahjong.

Therefore, if you use your eyes uncontrollably, you may have to report to the eye clinic frequently!

(Kuala Lumpur News) Dry eye syndrome is one of the common diseases in ophthalmology clinics. First, let us first understand the tear film, which is a liquid film covering the surface of the eyeball that lubricates and protects the cornea and conjunctiva. Although the tear film is thin and transparent, its structure can be divided into three layers from the inside to the outside, namely the mucin layer, the aqueous layer and the lipid layer.

Normally, the tear film is always present, but when a person stops blinking, the tear film evaporates. The mucus layer is mainly secreted by conjunctival goblet cells (goblet cells), which can stabilize the tear film; the aqueous layer in the middle is composed of water and water-soluble proteins, which can provide nutrients to the cornea; the lipid layer can prevent tears from flowing too quickly Evaporate.

Therefore, dry eye syndrome can also be divided into two types: Aqueous Tear Deficiency (ATD) and excessive tear evaporation dry eye (evaporative), with the latter being the most common.

Hormonal changes are to blame

Dr Then Kong Yong, consultant ophthalmologist and cornea specialist, pointed out that in fact, most people will develop some degree of dry eye syndrome at a certain age, and most of the causes of dry eye syndrome are difficult to determine.

“However, hormonal changes are a known cause, and menopausal women are more likely to suffer from dry eyes. In addition, patients undergoing excimer laser in situ keratomileusis (LASIK) may also Will experience dry eye syndrome.”

“Many patients with dry eye syndrome are also found to have mild inflammation of the eyelid (eyelid) edges, known as blepharitis. Blepharitis can damage the quality of the tear film and cause dry eye symptoms. Blepharitis can cause swelling of the eyelid edges. It can be red, itchy or painful, and sometimes you can see crusty debris stuck to the eyelashes. Although it is not contagious, blepharitis can affect both eyes.”

He cautions that if left unchecked, blepharitis can cause other eye problems such as cysts, styes or conjunctivitis. Therefore, the cleaning of eyelids cannot be ignored.

Severe eye redness, swelling and pain

Dry eye syndrome is usually diagnosed based on symptoms, he said. Mild cases include mild irritation, burning, grittiness, itching and intermittent blurred vision. In fact, dry eyes sometimes cause watery symptoms called pseudoeporia. This is caused by the surface being too dry, stimulating the tear glands to secrete large amounts of reflex tears.

Most cases of dry eye are mild, but severe cases may cause persistent eye redness, swelling and pain. If the cornea is severely scarred, it can lead to blindness. These patients often suffer from a condition such as Stevens-Johnson Syndrome (SJS) or from chemical burns that lack the goblet cells of the conjunctiva, causing scarring and blindness, but are very rare.

“Tears contain immunoglobulin A (IgA),

Lactoferrin

and other antibacterial substances that help protect the eyes from bacterial infections,

Dry eye syndrome increases the risk of infection.

For example,

SJS patients are more likely to develop bacterial corneal ulcers (bacteria cornea ulcer).

Their corneas may even melt.

Even if there is no infection, when the eyes continue to be dry,

The cornea also gradually thins and becomes perforated. “

He reminded that severe dry eye syndrome may also gradually cause the reduction and deficiency of limbal stem cells (Limbal Stem Cells, LSCs). Loss of LSCs due to inflammation, genetic disease or burns is one of the main causes of chronic ulcers and blindness. These stem cells are located on the limbus at the junction of the cornea and the white of the eye and have the ability to repair and regenerate damaged tissue. Patients who lack limbal stem cells have difficulty recovering from eye wounds, resulting in corneal scarring.

Test strips to test tear production

“What these patients need is not just dry eye treatment, but another more complex surgery called autologous cultured oral mucosal epithelial transplantation (COMET). Because the cells in the oral cavity are similar to those on the conjunctiva of the eye, they both contain cup-shaped cells, so we will extract stem cells from the mouth and culture them in the laboratory. Afterwards, we will transplant the stem cells into the eyes to encourage the eyes to secrete more mucin and stabilize the tear film.

However, this is a complex and rare treatment, and only one ophthalmology center in Malaysia offers this service. “

If a patient has dry eye symptoms, the ophthalmologist will use a slit lamp microscope to look at the eyelid margins and surface of the eye. A special fluorescent dye (stain) is placed in the eye to check for microscopic damage caused by dryness.

Doctors also assess whether a patient’s dry eye syndrome is due to rapid evaporation or reduced tear production, he said. When patients complain of very dry eyes or persistent tearing, a Schirmer test is commonly used to determine tear production.

In addition to slit lamp microscopy, there are now new instruments such as the non-invasive Ocular Surface Analyzer (OSA) that can perform several examinations, such as the evaluation of the tear film meniscus (tear menicus) and the lipid layer of the ocular surface. Thickness and distribution, blink pattern, etc., provide a comprehensive analysis to understand which layer of the tear film problem is causing the patient’s dry eye syndrome.

For example, Meibomian Gland Dysfunction (MGD) is known to be one of the main causes of dry eye syndrome, and OSA can identify the number of meibomian glands through meibography. The meibomian glands produce oily meibum fluid, which slows the evaporation of the aqueous layer.

Artificial tears have their own pros and cons

There are many types of artificial tears on the market that can be used to treat dry eye syndrome. They are broadly divided into drops, gels and ointments, and there are also preservative- and preservative-free formulations.

He also emphasized that these products have their own advantages and disadvantages, such as the drops are easy to use, can be easily carried and used at any time, and are economical. Artificial tear gel is a little tricky to use and the user’s vision will be blurred for a few minutes, but the effect lasts longer than drops, so it doesn’t have to be used as frequently. As for the ointment, the effect lasts longer, but the blurred vision will last longer after use, so it is best to use it before going to bed.

Generally speaking, artificial tears without preservatives are better, but the price is relatively higher. Patients with mild dry eye disease who wear glasses can use general artificial tears, but use them more frequently (more than 4 to 5 times a day); those who wear contact lenses and patients with severe dry eye disease are recommended to use preservative-free artificial tears.

Tear duct plugs reduce tear loss

Optional pulsed light therapy for mild cases

As the medical community better understands the causes of dry eye, new artificial tear alternatives are emerging, such as cyclosporine, which targets the inflammatory part of dry eye, but they can only be prescribed by an ophthalmologist.

In addition, there are also new artificial tears on the market, which mainly stimulate conjunctival goblet cells to secrete more mucin.

Zheng Kangyong pointed out that punctual plugs are also an effective method to treat dry eye syndrome. It reduces tear loss and increases the time artificial tears stay in the eye. Tear duct plugs are made of silicone and can be removed when necessary. It should be noted that if the effect of the tear duct plug is excessive, it will cause excessive tearing symptoms.

3 courses of treatment without hospitalization

“Most dry eyes caused by MGD are mild. Artificial tears containing oil can be used. If the effect is not big or severe, pulsed light therapy (Intense Regulated Pulsed Light, IRPL) can be chosen, which can help reduce blepharitis and Unclogs the meibomian glands to improve function. The treatment covers 3 sessions, is painless and does not require hospitalization. Each eye is exposed to only a few minutes and costs approximately RM1,700.”

Decreased tear production due to corrective surgery

Question 1. Why do my eyes get dry easily after corrective surgery such as LASIK?

Answer 1.Many patients who undergo LASIK surgery mention dry eye problems, but most cases disappear within 6 months, and only a few patients suffer from long-term dry eye problems.

Although the cause of dry eye after LASIK has not yet been determined, a loss of the mucus layer on the surface of the cornea may be the culprit.

The function of the mucus layer is to reduce surface tension, allowing for better distribution of tears throughout the eye. Since the corneal nerves may be damaged during the LASIK process, the corneal sensation will decrease and tear secretion will decrease.

Text◆Chen Wenbin (President of the Hong Kong Society of Optometrists)

Primary eye care

Recently, I collaborated with an NGO to provide a group of cleaning workers with comprehensive eye examinations and eye health lectures, which included visual acuity, prescription, and intraocular pressure examinations, as well as using diagnostic drugs to dilate the pupils to see if there are cataracts, jaundice, etc. Degeneration of spots and eye problems due to diabetes.

It was found that most of the workers had never had an eye examination, and they were not even aware that they had cataracts and other conditions. Some workers’ vision was as poor as only 10% to 20%.

I can’t help but think that good vision is a basic element of physical and mental health. In addition to affecting daily life, work performance and even economic status, poor vision can also easily lead to serious health problems due to falls. In the highly developed Hong Kong, why don’t the public know how to protect their eyesight? This actually involves a very important concept – primary eye care.

Hope grassroots eye care works

Primary eye care is an important part of the primary healthcare system, and the concept is to serve as the first (without referral) point of contact (easily accessible near the community where one lives and works). Involves basic care and routine examinations to prevent diseases. In Hong Kong, the word “primary care” has another meaning, referring to classes and disadvantaged groups that lack resources; the general public may not understand that primary care is a healthcare concept.

For example, friends talk about eye problems: “My eyes seem to be blurred when I see recently. Why can’t I find an optometrist’s eye examination service when I go directly to a public hospital?”

“My eyes seem to be white. Do I have cataracts?” Or a friend waited for a long time in a public hospital for an “eye test”, but after seeing it, he said there was no problem and closed the file. Why is there no follow-up date for “regular eye test”? Woolen cloth? The above questions are often shared by the elderly in the eye examination room.

I can only explain that hospitals are mainly used for treatment (secondary care) rather than routine examinations. The World Health Organization emphasizes the importance of integrating primary eye care into primary care. Everyone has access to primary care health facilities in the community for basic eye problems, rather than flocking to overused hospitals.

Registered Optometrists (Part 1) receive 5-year university training in order to play a role in primary eye care, including promoting eye health, preventing diseases that lead to vision loss, and strengthening referral pathways and vision rehabilitation.

Encourage regular eye examinations

There are many registered optometrists (Part 1) in the community who provide comprehensive eye examinations, including a series of comprehensive investigations to protect vision and eye health, and serve people of different ages. For example, dilating students’ pupils to check refractive index such as farsightedness, myopia, astigmatism, etc., and checking the coordination ability of the eyes to find out development deviations such as strabismus and amblyopia; checking whether workers will have dry eyes after long-term computer work; for invisible Provide regular care for glasses wearers; dilate pupils for middle-aged and elderly people to check for degenerative eye problems, such as presbyopia, cataracts, or the risk of degenerative eye diseases such as glaucoma and macular degeneration.

As for those with visual impairment, they can also find a registered optometrist (Part 1) for vision rehabilitation training, etc. All of the above vision care can be done in the community.

As the population ages and people use more electronic products, the need for eye care is also increasing. Many people already receive regular comprehensive eye examinations from registered optometrists (Part 1) every year. However, many people’s awareness of primary eye care is still weak. We hope that the government will encourage people to receive regular primary comprehensive eye examinations through policies. , including seeking professional advice from an optometrist.

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