Dry Eye Disease (DED) is one of the most common eye disorders worldwide. It is a multifactorial disease of tears and the ocular surface broadly due to reduced production or increased evaporation of tears, both of which are necessary for good vision, leading to the following:
- symptoms of discomfort,
- visual disturbance,
- tear film instability, and
- inflammation of the ocular surface.
DED is characterized by loss of homeostasis of the tear film of the eye and can result in a vicious cycle of corneal epithelial damage and inflammation; this is an important clinical concept that may help to determine approaches to management.
PREVALENCE:
The global prevalence of DED is not constant and is observed to be highest in Southeast Asia and lowest in Europe and the USA. The prevalence is noted to increase with age, and higher in women, especially those who have undergone menopause.
ETIOLOGY:
● Inadequate tear formation: Owing to various medical conditions or as a side effect of certain medications, tear production tends to decrease with age. Symptoms of DED can develop when the normal amount of tear production reduces.
● Increased tear evaporation: DED symptoms can develop when tears evaporate too quickly or do not evenly spread over the cornea due to deficit in any of the three tear layers. Moreover, environmental conditions such as wind and dry climate can increase tear evaporation and subsequently diminish the tear volume. Meibomian gland dysfunction often leads to this type of DED.
The following are some factors associated with DED:
- Certain diseases like rheumatoid arthritis, Sjogren’s syndrome, thyroid disease, and lupus
- Blepharitis
- Entropion, ectropion
- Exposure to smoke, wind, or an excessively dry climate
- Increased screen time, reading, and other activities that reduce blinking
- Decreased corneal sensation
- Prolonged use of contact lenses
- Having refractive eye surgery such as LASIK
- Use of certain medicines like diuretics, beta-blockers, allergy and cold medicines, and anxiety and antidepressant medicines
SYMPTOMS:
- Stinging and burning of eyes
- Blurred vision, especially while reading
- Scratchy or gritty feeling like something is in the eye
- Mucus string in or around the eyes
- Red eyes, especially on exposure to wind or cigarette smoke
- Pain on wearing contact lenses
DIAGNOSIS:
Comprehensive eye examinations are conducted to assess patients with DED, such as:
- maintaining records of symptoms and any health problems, medications, or environmental factors that may be contributing to the DED;
- recording different observations and measurements like tear secretion, tear clearance, ocular surface damage, tear film stability, tear volume, lipid layer assessment, and tear osmolarity;
- examining the eye externally (lid structure and blink dynamics);
- evaluating eyelids and cornea using bright light and magnification;
- measuring the quantity and quality of tears for any abnormalities (special dyes may be injected in eyes to observe tear flow and to highlight any changes to the outer surface of the eye caused by insufficient tears);
- performing slit lamp examination in every patient; and
- measuring osmolarity as it correlates best with severity in DED (however, for clinical purposes, Schirmer’s test remains a useful measure of tear production).
Diagnosing and treating DED can be tricky and time-consuming. Patients usually require a combination of treatments, with lifestyle changes, to bring effective and lasting relief.
PREVENTION:
- Avoiding the use of hair dryers.
- Avoiding rooms with high temperatures. Humidifiers can be used in winters.
- Protecting eyes from dry wind by wearing wraparound glasses when outdoors.
- Adding omega-3 fatty acids to the diet for dry eye relief. They are naturally found in oily fish and flaxseeds or can be added as a dietary supplement.
- Using artificial tear ointment or thick eye drops before bedtime to prevent waking up with dry and scratchy eyes.
TREATMENT:
Current treatments for ocular surface disease include lifestyle changes, a nasal spray, punctal plugs, anti-inflammatory medications, deep cleaning devices, and specialized contact lenses. For irritated eyes, the following is typically prescribed:
● Prescription eye drops or ointments
● Warm compresses on the eyes
● Massaging of eyelids
● Certain eyelid cleaners
NEWER TREATMENTS:
The following are a few FDA-approved prescription medications for DED:
- Varenicline is a highly selective cholinergic agonist that binds to cholinergic receptors with high affinity and activates the trigeminal parasympathetic pathway, accessible via the nose, resulting in enhanced basal or natural tear film production. This nasal spray may be easier to apply than eye drops, and it eliminates undesirable ocular stinging and burning sensations.
- Cyclosporine-based medicines were specifically developed for chronic DED where inflammation leads to reduced tear production. The treatment can take 3 to 6 months to be effective and may cause temporary burning or discomfort.
- Lifitegrast is administered as an anti-inflammatory eye drop, and the medicine can take up to 3 months to relieve symptoms.
- Loteprednol is the first ocular corticosteroid approved by the FDA for treatment of dry eye flares. Given the side effects of steroids, it can only be used for 2 weeks at a time. It works more quickly than immunomodulator-based medicines, and both may be used in conjunction to alleviate symptoms.
- OptiLight is an intense pulsed light (IPL) device that was approved by the FDA in 2021. It aims to improve the symptoms of DED caused by meibomian gland dysfunction.
The new treatments for DED target following problems:
- underlying inflammation (blepharitis, uveitis),
- meibomian gland dysfunction, and
- allergic conjunctivitis.
Despite DED being one of the most universal and uncomfortable eye conditions, few newer treatment options have been introduced so far.
New Hope in DED treatment:
Link_TSG6, a biological drug that harnesses the protective effects of TSG-6, a protein that is made in our bodies in response to inflammation and injury, was studied in two validated mouse models of DED. The results showed that topically administered Link_TSG6 dose-dependently reduced corneal epithelial defects and suppressed inflammatory markers while increasing tear production and conjunctival goblet cell density. Thus, it appears to be a promising treatment for DED.
CONCLUSION:
The understanding of DED has considerably advanced over a period of time, leading to improvements in detection and management of this common condition, which have benefited many DED patients. There is a desperate need for treatments that rapidly and significantly improve the signs and symptoms of DED and provide patients with an improved quality of life.
OUR SERVICES:
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