Given the growing emphasis on ocular surface optimization in refractive cataract surgery, Darrell White, MD, a cataract and refractive surgeon in Cleveland, Ohio, speaks with Himani Goyal, MD, about why Demodex evaluation belongs at the start of every pre-surgical ocular surface exam. Dr. Goyal is a cataract and cornea specialist at NYU Langone Health and Bellevue Hospital in New York, where she also teaches ophthalmology residents.
Demodex blepharitis fast facts
- Demodex blepharitis (DB) frequently contributes to chronic lid margin inflammation and meibomian gland dysfunction.1
- The prevalence of Demodex blepharitis is high. In a study involving over 1,000 US eyecare patients, collarettes, the pathognomonic sign of Demodex blepharitis, were identified in 57.7% of patients.2
- Treating DB before cataract or refractive surgery may help optimize the ocular surface, improve measurement accuracy, and support better visual outcomes and patient satisfaction.3,4
- Lotilaner ophthalmic solution, 0.25% (Tarsus Pharmaceuticals), is the first FDA-approved treatment that directly targets Demodex mites.5
- The introduction of an FDA-approved treatment for Demodex blepharitis has prompted many clinicians to implement routine screening as part of comprehensive eye examinations.6
A deeper dive into Demodex screening before ocular surgery
Drs. White and Goyal emphasize that ocular surface optimization begins long before patients enter the operating room. Demodex blepharitis is increasingly recognized as an important contributor to ocular surface inflammation that should also be addressed at the start of the pre-surgical examination—before diagnostic drops are instilled or ocular measurements are obtained.
“The very first thing I look for is Demodex infestation.”
Demodex mites are the most common ectoparasites found on human skin. Demodex folliculorum inhabits eyelash follicles and causes the characteristic collarettes, or cylindrical dandruff, seen at the base of the lashes. Demodex brevis resides within the meibomian glands, where it may contribute to gland dysfunction and tear film instability.1
Incorporating DB screening into ocular surface exams
For clinicians, recognizing Demodex can be straightforward, but Dr. White emphasizes that timing matters. Rather than waiting until later in the examination, he begins by evaluating the eyelids for signs of Demodex before assessing the broader ocular surface. Drs. White and Goyal stress that identifying Demodex is only one component of a comprehensive ocular surface evaluation.
They also assess patients for additional signs of meibomian gland dysfunction and ocular surface disease, including:
- Lid margin erythema
- Telangiectasia
- Inspissated or capped meibomian glands
- Rapid tear break-up time
- Tear film debris
- Fluctuating visual quality
If left untreated, these findings may result in inconsistent vision, ocular discomfort, and diminished patient satisfaction following surgery.
“My threshold to treat is very low. The second I see any signs of Demodex, I treat it.”
Dr. Goyal explains that the meibomian glands play a critical role in maintaining a healthy tear film. The lipid layer these glands produce slows tear evaporation, and disruption of normal gland function can accelerate tear break-up and worsen evaporative dry eye symptoms.
Since cataract and refractive procedures can temporarily exacerbate ocular surface inflammation, managing pre-existing disease prior to surgery may promote improved visual outcomes and a more comfortable postoperative recovery.
Why treatment matters before surgery
Ocular surface disease can influence keratometry, biometry, and other pre-operative measurements. Identifying and treating Demodex infestation prior to surgery may enhance refractive accuracy and improve the overall patient experience.
The discussion underscores a key treatment consideration. While topical corticosteroids may provide temporary reduction of inflammation, they do not eradicate Demodex mites. Dr. Goyal notes that studies indicate mite populations may increase following corticosteroid therapy, emphasizing the necessity of addressing the underlying cause of inflammation rather than solely treating the inflammatory response.
“If we're not getting to the root cause of that inflammation, the steroids will decrease inflammation, but they won't take away the Demodex mites.”
Drs. White and Goyal also highlight the importance of patient education. Presenting patients with slit-lamp photographs of collarettes can facilitate understanding of the rationale for treatment and reinforce the potential impact of Demodex on vision, comfort, and surgical outcomes.
In conclusion
With ocular surface optimization gaining prominence in refractive cataract surgery, routine evaluation for Demodex blepharitis is emerging as a practical component of the standard pre-operative examination.
Early identification and treatment of Demodex may reduce ocular surface inflammation, enhance tear film stability, and better prepare patients for favorable surgical outcomes.
This article was written by Lindsay Curtis based on the recorded conversation between Drs. White and Goyal.
