Corneal conditions: Importance of early detection and management

Image credti: AdobeStock/vxnaghiyev/AI

In a recent Optometry Times Insights discussion, Crystal Brimer, OD, FAAO, and Jacqueline Theis, OD, FAAO, explored the timely diagnosis and management of common corneal diseases. Theis and Brimer pointed out that undiagnosed dry eye, superficial punctate keratitis (SPK), and exposure are very common in practice.

Because they both see trauma in their practices, Theis and Brimer see many cases of neurotrophic keratitis and neuropathic pain. In patients with brain injury from trauma, stroke, or diabetes, the cornea lacks corneal sensitivity, which affects blinking, with resultant exposure. Interestingly, patients with a history of brain injury are more likely to have dry eye than patients without brain injury. Theis noted that clinicians equate photophobia with brain injury; however, in many cases, photophobia is simply glare, because patients are not sleeping and their eyes are dry.

Corneal dystrophies are another issue for Brimer. “Unless all the corneal layers are evaluated, corneal dystrophies can be overlooked if patients are asymptomatic. Dystrophies are important to document because they contribute to symptoms and disease and compromise the corneal integrity,” she said.

Differential diagnosis

Corneal disorders are difficult to diagnose because of the overlap of the signs and symptoms of many corneal conditions, Theis commented. When patients present with red, tearing eyes, the most important underused tools are fluorescein dye and lissamine green, which are helpful and do not affect nerve function, she explained. She does not use rose bengal often but relies on sodium fluorescein to assess the tear breakup time.

Theis emphasized the importance of lid evaluation because of nocturnal lagophthalmos in patients with brain injury when the orbicularis oculi is not functioning properly. Lid taping at night may be a simple fix, or surgery may correct the problem.

For her, the most important step is a complete examination to narrow the differential diagnosis and identify dysfunctional blinking, blepharitis, or Demodex blepharitis, the last of which is common in previously hospitalized patients. Because of the discomfort associated with every blink, proper treatment can improve patients’ quality of life.

For Theis, patient history is key. The time of onset is relevant because punctate keratitis can have a lot of differentials, she explained.

According to Brimer, in a dry eye referral center, recurrent corneal erosions are common and clinicians should be alert for them. Signs of a recurrence may include fragile-looking epithelium or a regeneration line.

Infrequent findings

Corneal ulcers are not seen as often in Theis’ chronic care practice as they are in acute care practice for contact lens wearers. Infectious causes (eg, fungus, Acanthamoeba, and Pseudomonas) along with simplex keratitis are also less common in primary eye care practices but should be considered in the differential diagnosis.

Early detection

Brimer has become increasingly aware of the importance of early diagnosis. When she sees any degree of staining, she no longer observes the patient and offers direct and aggressive intervention options.

Theis explained that patients with neurologic issues do not respond like other patients in an ocular surface clinic because most of them have neuropathic or neurotrophic problems, an understanding that she has gained over time. “Early intervention is important because many patients with neuropathic eye pain have had untreated dry eye for long periods. When a patient has ocular surface inflammation that is not treated normally, the nerve will fire a signal to the brain to express pain,” she explained.

Without treatment, the nerve signal can permanently turn on the second- and third-order neurons and, despite appropriate corneal treatment, the pain can become chronic and harder to treat. “I do not wait until I see SPK to treat dry eye. With intermittent blurry vision, a tear breakup time below 5 or 6 seconds, or risk factors for dry eye, I proactively treat those patients, especially in my clinic when patients present after brain surgery,” Theis said.

Patient education and testing

Theis emphasized the importance of patient education about her examination steps (eg, evaluating eyelashes for evidence of infection, evaluating meibomian gland function, and simultaneously underscoring the importance of annual eye examinations). She relies heavily on sodium fluorescein staining and the proparacaine challenge. She explained that for a patient presenting with dry eye complaints, if the problem is nociceptive SPK pain, they should feel better when proparacaine is instilled. However, if pain persists after the instillation, they have neuropathic pain requiring longer treatment. This step is very helpful diagnostically, she said.

Brimer and Theis consider testing for corneal sensitivity mandatory for patients with diabetes and histories of herpes or laser-assisted in situ keratitis who are more likely to have sensitivity issues that will not present until their problems are advanced. Neurotrophic keratitis can result from contact lens wear and some rare but serious conditions such as acoustic neuromas. Testing cranial nerve 8 may reveal a different hearing level in 1 ear. A patient’s life can be saved by recognizing the need for a brain scan.

Brimer reported that every patient with dry eye has decreased corneal sensitivity, and her go-to is the “Q-tip test,” wherein she uses the softened end of a cotton swab to gently prod the zones of the cornea to test for reactivity. Theis uses the same test but prefers to use unflavored dental floss to test her patients. When clinicians recognize decreased corneal sensitivity, they can treat the patient differently from dry eye and educate them about their condition.

Another routine evaluation is looking under the patient’s lid to get a vertical view of the lashes and their base to rule out collarettes. She also advised examining the meibomian gland orifices, identifying hidden fine trichiasis under the lid, superior limbal keratitis, or a wayward contact lens.

Diagnostic technologies

In addition to a camera attached to her cell phone that she uses as a teaching tool, Theis is excited about upcoming technology that can measure corneal anesthesiometry to identify hypofunction and hyperfunction and evaluate corneal hyperalgesia. Optical coherence tomography (OCT) can visualize the corneal layers to see, for example, a small amount of stromal haze that is invisible by slit lamp. “If a patient has unexplainable reduced vision and symptoms, I use OCT to capture a picture of the cornea, measure the corneal thickness, and identify edema,” she explained.

Brimer depends on the OCULUS Keratograph 5M, a corneal topographer with a built-in keratometer and color camera. This instrument visualizes thelipid layer and oil as well as tear film debris and measures the tear meniscus height. She obtains pictures and fluorescein videos and shows patients the partial blink, staining, and evaporation. She then obtains a lissamine green picture that shows the lid margins, wiper epitheliopathy, and conjunctival staining. “By showing them what you’re looking for, they have a better sense of the treatment goals, which give them a reason to adhere to treatment despite [the fact] that they have started to feel better,” Brimer said.

Managing common corneal conditions

Diagnosing is key and goes hand in hand with appropriate testing. The first go-to treatment is over-the-counter products for mild dry eye. When the patient has a neurotrophic cornea but no keratitis, this can be prevented with nonpreserved artificial tears. Most people, Brimer pointed out, need lubrication. If the eyes improve, they have regular dry eye.

She also explained that warm compresses applied for 10 minutes provide much better efficacy over time than most other treatments. “We should tell patients that warm compresses and heat applied to the eyelids help meibomian gland disease and are one of the most effective ways to treat dry eye and the associated pain. This regimen must be followed daily. It’s not as easy as a drop but obtains better result,” she said.

Brimer described that an alternative to warm compresses is the NuLids device, which is similar to a toothbrush and helps liquefy and move meibum without heat. For patients needing a more aggressive approach, such as intense pulsed light (IPL) therapy, low-level light therapy, and radio frequency, LipiFlow (Johnson & Johnson), TearCare (Sight Sciences), Cequa (Sun Pharmaceutical Industries), and Viva Dry Eye Therapy (Amcon) are options. Theis explains that the key to the treatment choice is determining the source of the keratitis and not assuming all patients have the same dry eye condition and treating them with drops.

For patients experiencing treatment failure on tears after long-term use, insurance companies may block coverage of another type of dry eye therapy or prescription eye drops that may be prohibitively costly. Use of drops 4 times daily with no beneficial effect may signal the need for another therapy.

Theis also emphasized that patients should not be overloaded with treatments at once because that is a recipe for failure. Additional treatments should be introduced slowly to ensure that they are incorporated into the patient’s care regimen.

In her practice, Brimer focuses on incorporating lifestyle changes, such as adding ω-3 supplements and changes in diet and sleep. She discusses exercise, anxiety, stress, depression, and smoking. She also treats the inflammation, meibomian gland disease, bacteria, and allergy separately. Patients with advanced cases undergo in-office treatments (eg, IPL, radio frequency, and low-level light). In cases where the resolution is dubious, she adds a prescription drug. For her patients who are receiving the in-office treatments and tape their eyes shut at night but for whom staining persists, she addresses the neurotrophic element with proparacaine.

For Theis’ patients with more advanced neurotrophic keratitis in whom staining persists despite those previously mentioned treatments, she prescribes cenegermin-bkbj ophthalmic solution 0.002% (Oxervate; Dompé), plasma-rich protein drops, and autologous serum tears. When medications prove ineffective, there are surgical options.

She emphasized that each case is different and that the source of the pain must be treated, which may be chronic dry eye. In her clinic, the neuropathic pain often originates from the trigeminal neuralgia or occipital neuralgia. Some cases may be referred to a pain management specialist.

Musculoskeletal or cervicogenic pain, mentioned infrequently, can cause eye pain, and the patient may be referred to an orthopedic physical therapist. “The pathophysiology of our neck muscles overlaps with the pathophysiology of our corneal nerves at the superior cervical ganglion level,” she explained.

Key takeaways

For Theis, a complete anterior segment evaluation is a must. She follows this with specific questions to her patients about the status of their eyes and whether they are experiencing pain.

Because all her patients have a brain injury and memory lapses, she provides handouts with information she discussed during the examination. The handouts have boxes to be checked indicating that they read the material. This homework provides an opportunity for them to ask questions during the next examination or report information about a condition that had not been mentioned previously.

There is no one best treatment for corneal sensitivity and dry eye disease, but there are plenty of choices on the market. Intensive curiosity and thorough questions during diagnosis will help pinpoint where to begin, but it’s up to the optometrist to decide what is best for their patient.