OSD in the Blink of an Eye

Although blinking is thought to be a simple function, its mechanics have complex dynamics that play a vital role in protecting the eye and maintaining a stable tear film. Various intrinsic and extrinsic factors can alter both blink rate and blink completeness, including neurologic changes from a nerve palsy or stroke; anatomic changes from aging, injury, or previous surgery; and environmental factors, such as digital device use.

In this article, I discuss the role of blinking in the context of ocular surface disease (OSD) and offer insights for educating patients and instituting management strategies to address any disruptions in blink dynamics that are encountered.

BLINKING AND TEAR FILM MAINTENANCE

To understand how blinking affects the ocular surface, we must first understand its relationship to tear film creation and maintenance. The delicate balance of each layer of the tear film is what creates the perfect homeostasis needed for tear film stability and optical clarity. The composition of the tear film includes the inner mucin layer, middle aqueous layer, and outer lipid layer. The innermost layer of mucin is secreted by the goblet cells of the conjunctiva, while the aqueous layer of the tear film is created in the lacrimal gland and is continuously secreted into the conjunctival fornix. The outermost lipid layer of the tear film is created within the meibomian glands of the upper and lower eyelids. Ideally, the force of each blink should allow meibum to be expressed along the lid margin upon lid closure and spread evenly along with the mucin and aqueous layers over the ocular surface as the lid opens.

However, prolonged intervals between blinks can lead to excessive tear evaporation, resulting in fluctuations in vision, burning, pain, and reflex tearing. With reduced blinking also comes limited meibum expressed from the meibomian glands. Meibum can become stagnant and thicken within the glands over time, resulting in meibomian gland dysfunction (MGD), which can further contribute to a tear film imbalance and excessive tear evaporation.¹ Incomplete blinking causes similar effects and poses an increased risk for excessive tear evaporation and, therefore, increased exposure to the lower half of the cornea.

ASSESSING BLINK QUALITY

Simple steps can be taken to better evaluate how blinking mechanisms may be affecting a patient’s ocular surface. For one, have patients complete a dry eye symptom questionnaire, such as the Standardized Patient Evaluation of Eye Dryness or the Ocular Surface Disease Index. These surveys can be delegated to staff when they are taking patient history, especially in those whose chief complaints indicate symptoms related to OSD.

Another helpful tip is to regularly discuss computer and digital device use with each patient. This should include noting the types of devices they use and the total time they spend on those devices per day. As you walk in the room and introduce yourself, you can start making observations immediately. For example, I always make note of whether the patient is on their phone when I walk in, which clues me in to their typical device use. I also like to look at the patient’s face, noting any significant anatomic changes that could possibly contribute to altered blinking mechanisms, such as a nerve palsy, ptosis, dermatochalasis, ectropion/entropion, or proptosis.

Behind the slit lamp, watch how your patients are blinking, and take note of blink rate and completeness. A patient should be blinking completely every 3 to 6 seconds. Fluorescein staining is essential to evaluate tear breakup time and assess corneal health (Figure). In addition, if you have a slit-lamp camera with photo and video capabilities, record the patient’s blinks to help you educate them later on the importance of blinking and how it relates to their symptoms.

The meibomian glands should also be evaluated for MGD using any of the methods below.

• Conduct a careful slit-lamp assessment, looking for capped glands and lid margin changes, such as lid margin notching, erythema, or telangiectasia.
• Perform gland expression with digital pressure, a cotton-tipped applicator, or special-expression forceps to assess the quality of meibum.
• Use imaging with infrared meibography to document the structure of the meibomian glands.

In addition, new technology, such as the TearScience LipiView II Ocular Surface Interferometer (Johnson & Johnson Vision) and M&S Bruder Ocular Surface Analyzer (Bruder), can objectively quantify the number of complete and partial blinks, along with other compelling OSD data.

PATIENT EDUCATION

Once you have determined the patient’s blinking dynamics could be contributing to their OSD, the next step is to educate them on your observations. I find that pictures and videos, such as those you have captured of the patient while they are in your office or from a photo library of similar findings, are the best way to provide clear education. Discuss with them what factors might be contributing to the changes in their blinking and how blinking contributes to tear film production and stability. Be sure to relate this back to the patient’s specific ocular surface symptoms.

Next, create a customized treatment plan. OSD is multifactorial, so discussing blinking and MGD may only play a small role in this plan. A step-wise approach may include at-home and in-office treatments, prescription medications, nutraceuticals, biologics, and lifestyle and/or behavioral modifications.

DIGITAL DEVICE USE AND BLINK DYNAMICS

The most common factor that can alter blink dynamics, in my opinion, is linked to increased digital device use, which contributes to OSD and MGD. Studies have shown that blink rates can be reduced by almost half when working on a computer or device compared with the blink rate at rest.^1,2 Incomplete blinking has also been noted in patients using digital devices, resulting in “half blinks,” which lead to disruption in the production and distribution of the tear film.

Several options can help address MGD, blinking dynamics, and tear evaporation for dry eye changes related to digital screen use.

Improve Meibum Quality and Expression

First-line treatment may involve daily use of warm compresses at home. A variety of compresses are available on the market, including microwaveable, electrical, and disposable options. More advanced treatments may include in-office thermal pulsation, radiofrequency, intense pulsed light therapy, and low-level light therapy. You may also consider supplementation with nutraceuticals and/or dietary changes to increase the patient’s intake of omega-3 fatty acids.

Behavior Modification During Screen Time

If increased demand on digital devices resonates with your patient, an additional step in treatment could involve behavioral modifications for patients during screen time, such as initiating blinking exercises and taking periodic breaks from screens throughout the day.

I find that a great way to help patients with this task is to have them set timers or calendar notifications to remind them to look away from their screens and blink throughout the day. Some patients might also benefit from supplementing with preservative-free artificial tears during screen time.

Eye Drops

A more recent development for preventing tear evaporation is perfluorohexyloctane ophthalmic solution (Miebo, Bausch + Lomb), which aims to create a barrier within the tear film to prevent evaporation of natural tears.³ Another option that targets evaporation is Systane Complete Lubricant Eye Drops (Alcon).⁴ I recommend that patients keep a bottle of preservative-free artificial tears near their workspace so they are easily accessible to use throughout the day.

NOT AS SIMPLE AS IT SEEMS

Blinking is a complex and dynamic function that can be easily influenced by anatomic, neurologic, and environmental factors. When blinking mechanisms are altered, such as by prolonged digital device use, the risk of OSD may significantly increase, as lower blink rate and increased percentage of incomplete blinks are linked to dry eye symptoms, rapid tear evaporation, and corneal staining.^1,2

Treating and preventing ocular surface damage in patients with altered blinking mechanisms requires good observation to identify those at risk of developing OSD and top-notch patient education to help them better understand how blinking—and time spent on digital devices—contributes to their ocular health.