Examining Meibomian Gland Structure and Function in Patients With Demodex Blepharitis

Findings from a retrospective analysis highlight the association between Demodex blepharitis and meibomian gland structure and function.

Cecelia Koetting, OD, FAAO, DipABO and Elizabeth Yeu, MD

Cataract and Refractive Surgery Today

Meibomian gland disease (MGD) is defined as dysfunction of meibomian glands (e.g. obstruction, atrophy, or poor-quality meibum) that leads to tear film disruption, visual disturbance, and ocular discomfort.1 Inflammation from Demodex mites may cause serious consequences, like Demodex blepharitis and MGD. When discussing MGD, it’s important to include consideration of concurrent Demodex blepharitis. According to a study published in 2022, 58% of US patients (n = 595/1032) who visited an eye care clinic and underwent a slit-lamp examination, regardless of chief complaint, had Demodex blepharitis, including consultations for cataract or refractive surgery.2 A retrospective study by Cheng et al reported a positive rate of Demodex infestation in MGD patients (89%; n = 103 eyes of 52 patients) compared to control (43%; n = 62 eyes of 31 non-MGD patients).3 In a separate single-center study, Bhandari et al concluded that the incidence of Demodex infestation was 60% for patients with MGD (n = 60) and 18% for control (n = 50).4 Finally, Lim Bon Siong et al reported that the overall incidence of Demodex blepharitis was 85% for MGD patients (n = 65) and 34% for control patients (n = 50).5 Although Demodex blepharitis may be asymptomatic in a small proportion of patients (≤1% in one prospective observational study of 515 patients; n = 4), most patients (98.3%) reported two or more symptoms.6 Symptoms can stem from Demodex mites triggering inflammation leading to swollen eyelid margins, reduced gland openings, and compromised meibum flow.7,8 Additionally, Demodex infestation may be an important contributor to inflammatory MGD and can lead to structural and functional changes in the meibomian glands.8 Symptoms from Demodex blepharitis and MGD can impact tear film stability and ocular surface integrity, and may also lead to altered biometry and abnormal corneal topography measurements, which can potentially affect cataract or refractive surgery planning and increase the risk of postoperative dissatisfaction.9-12 Therefore, evaluation for Demodex blepharitis should be considered when managing MGD, particularly in patients undergoing such procedures. Study Rationale and Design In early 2025, we published a study in the Journal of Cataract and Refractive Surgery to answer one primary question: How do structural and functional measures of MGD compare in eyes with moderate-to-severe Demodex blepharitis (collarette grades 2–4) versus those with collarette grade 0? For this retrospective, single-center, observational study, we examined case records of 438 patients ≥18 years with available data for collarettes and MGD signs (e.g., telangiectasia, meibum expressibility, meibum quality, meibography).8 Collarettes were graded per eyelid on a 0 to 4 scale: Grade 0: 0 to 2 lashes/eyelid with collarettes. Grade 1: 3 to 10 lashes/eyelid with collarettes. Grade 2: >10 to <1/3 (~50) lashes/eyelid with collarettes. Grade 3: ≥1/3 to <2/3 (~100) lashes/eyelid with collarettes. Grade 4: ≥2/3 (~150) lashes/eyelid with collarettes.

The First Win Is On The Surface

Cathleen M. McCabe, MD

Cataract and Refractive Surgery Today

Key Takeaways Ocular surface disease management belongs at the start of cataract and refractive surgical planning because tear film instability makes preoperative measurements unreliable, reduces refractive accuracy, degrades postoperative visual quality, and compromises patient satisfaction. Stable ocular surface data support a sound surgical plan from the outset. Patients with ocular surface disease often lack classic dry eye symptoms and instead attribute blur, glare, fluctuating vision, irritation, or reduced visual quality to cataract, a cloudy capsule, or an imperfect surgical result. Early tangible improvement builds trust in the diagnosis and strengthens treatment adherence. Long-term, multifaceted ocular surface disease management gains traction when patients experience an early win in comfort or visual quality, a milestone that supports reliable measurements before surgery and reassures dissatisfied patients after surgery. Newer therapies and treatment strategies make these early wins more achievable. Guidance on ocular surface disease (OSD) management is plentiful. Cataract and refractive surgeons understand how tear film instability can affect preoperative measurements, the refractive accuracy of surgical intervention, patients’ postoperative quality of vision, and, ultimately, their satisfaction. We also know how common OSD is in our patient population. For many of us, however, the ocular surface remains a secondary consideration—something to address after measurements are taken, the IOL is chosen, or a patient returns dissatisfied.

Extending Treatment Efficacy in Wet AMD

Lejla Vajzovic, MD; Robert L. Avery, MD; Carl D. Regillo, MD; and Durga S. Borkar, MD, MMCi

Eyetube

Podcast moderator Lejla Vajzovic, MD, sits down with Robert L. Avery, MD; Carl D. Regillo, MD; and Durga S. Borkar, MD, MMCi, to explore how new therapies hold promise for extending treatment efficacy in patients with wet AMD. They touch on various drug delivery platforms, gene therapy, tyrosine kinase inhibitors, and the challenges of drug development and approval.