Carrington Family Vision Center, Dr. Kathy Hendrickson

02/06/2026

Physical examination of the meibomian glands
When evaluating the meibomian glands, I will be evaluating your eyelids, eyelid margins, eyelashes, and meibomian gland openings. I will also apply gentle pressure to your eyelids to evaluate the quantity and quality of the oil (meibum) secreted by your meibomian glands. The images obtained by the BOSA allow me to view the structure of the meibomian glands.  When the meibomian glands are healthy, meibum has a consistency similar to olive oil and flows easily. The arrows in the photo are pointing to healthy oil.
Coming up next: tear breakup time.

02/04/2026

Blog Update: Macular Degeneration--A Common Vision Condition

Age-related macular degeneration, often called ARMD or AMD, is the leading cause of vision loss among Americans 65 and older.AMD causes damage to the macula, which is the central portion of the retina responsible for sharp central vision. AMD doesn't lead to complete blindness because peripheral vis...

02/02/2026

Lids and Lashes
The BOSA takes magnified images of eyelids and eyelashes. Eyelids and eyelashes play an important role in protecting our eyes. Common eyelid and eyelash issues include: blepharitis, chronic inflammation, blocked and infected oil glands, and makeup allergies. Demodex blepharitis (photo) is caused by an overgrowth of Demodex mites. The collarettes at the base of the eyelashes are the key diagnostic sign of demodex blepharitis.
Coming up next: physical examination of the ocular surface.

01/31/2026

Tear Film Stability Assessment
The tear break-up time test measures how long your tear film remains intact after you blink. As you hold your eyes open, the BOSA assesses the tear film to determine when and where it starts breaking apart. A healthy tear film should remain stable for at least 10 seconds. Shorter break-up times indicate poor tear quality, often due to insufficient oil. The BOSA calculates the initial and average tear breakup time. It also gives a visual representation of when and where the tears are breaking up.
Coming up next: lids and lashes.

01/31/2026

Lipid Layer Thickness 
Lipid Layer Interferometry is used to measure the thickness and quality of the tear film’s lipid layer. It is used to monitor the tear film and plays a role in diagnosing dry eye disease.
Coming up next: tear film stability assessment.

01/29/2026

Meibum
This is not what meibum should look like. Meibum should be the consistency of olive oil. Prolonged intervals between blinks and incomplete blinking can lead to limited meibum expressed from the meibomian glands. Meibum can become stagnant and thicken within the glands over time resulting in meibomian gland dysfunction. The image shown was a case study of mine. I was not able to express any oil from the glands. The image below was taken after one dry eye treatment session. The meibum had softened to the consistency of toothpaste and was starting to flow (with help) out of the glands. I will share what the meibum looked like after the treatments were completed when I write about treatment options.
Coming up next: lipid layer thickness.

01/28/2026

Meibography and Meibum
Meibography a non-invasive technique used to capture images of the meibomian glands. The outermost lipid layer of the tear film (meibum) 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 and spread evenly along the ocular surface as the lid opens.
Coming up next: meibum

01/28/2026

Blog Update: What Does 20/20 Even Mean?

One of the most commonly asked questions in an eye exam comes right after the refraction, or glasses prescription check: “What is my vision?”Almost invariably, people know the term “20/20”. In fact, it’s a measure of pride for many people. “My doctor says I have 2...

01/27/2026

Tear meniscus height refers to the height of the tear film at the lower eyelid margin. It is an important indicator of ocular surface health and is used to assess conditions like dry eye syndrome. A healthy tear meniscus is crucial for maintaining eye comfort and function. Regular tear meniscus height assessments can help track changes in ocular surface health over time.
Coming up next: meibography.

01/26/2026

Eye Blink
Both blink frequency and efficiency play an important role in the health of the ocular surface. When blinking mechanisms are altered, the risk of ocular surface disease 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.
A normal blink rate is one blink every 3-4 seconds. When using electronic devices, the blink rate can drop to one blink every 8-12 seconds.
Coming up next: tear meniscus height.

01/25/2026

Patient History and Symptom Questionnaire
The evaluation starts with a detailed discussion of the patient’s medical history, including any preexisting eye conditions, medications, and environmental factors. Patients are asked to complete a questionnaire that assesses the severity and impact of their dry eye symptoms on their daily activities and quality of life. The BOSA calculates a score questionnaire allowing for comparison over time.
Coming up next: eye blink.

01/24/2026

After a brief introduction to the ocular surface we will jump back to the BOSA and how it can assist in clinical decision making and educating the patient. The BOSA can quickly and easily identify key ocular surface metrics. The BOSA dashboard allows for a quick assessment of test results prior to the comprehensive physical examination of the ocular surface.
Coming up next: patient history and symptom questionnaire