Dr Khang Ta
Evergreen Optical Carnegie
Demodex blepharitis is a common condition that is often overlooked, misdiagnosed and poorly treated. While Demodex mites can exist in the skin of asymptomatic patients, ocular infestation usually results in disorders of eyelashes, lid margin inflammation, meibomian gland dysfunction and blepharoconjunctivitis. In chronic, untreated cases, Demodex infestation can manifest as corneal disease, resulting in ocular pain, photophobia and vision loss.
Two Demodex species have been identified to exist in humans: D folliculorum and D brevis. D folliculorum can be found in the eyelash follicle whereas D brevis live in the sebaceous glands and meibomian glands. Our current understanding is that these mites exist parasitically in human. Demodex mites can cause blepharitis by introducing bacteria including Streptococci and Staphylococci.1 Bacterium living inside Demodex can also trigger a host immune reaction and even the dying mites can release bacterial antigens that can trigger a cascade of host inflammatory responses.
Figure 1. Before treatment
Figure 2. Treatment with BlephEx
The main symptoms include itching, grittiness, crusty eyelashes, redness and irritation. While cylindrical dandruff around eyelashes is a sign of Demodex infestation, eyelash extraction and high-magnification microscope examination should be performed to confirm a diagnosis.
Conventional treatments involving baby shampoo can be effective in removing eyelash dandruff but have no miticidal effect. Antibiotics are important in reducing the bacterial load but have no direct effect on the Demodex mites. Tea tree oil treatment is currently the best way to kill Demodex in vivo.2 Commercially available preparations are available for ocular use and these are essential for any practice-based or take-home treatment plan.
Take-home treatments can often be very effective with the right patient but without a practitioner-driven program and a practice-based strategy, even the most compliant patient can struggle to manage the condition.
As an optometrist who has actively treated Demodex blepharitis for 13 years, one of my key challenges has been to effectively remove the mites from the eyelids and eyelashes. BlephEx is a hand-held electrical tool that drives a disposable micro-sponge to exfoliate the eyelid and eyelashes. Used in conjunction with a tea tree eye wash, great results can be achieved and should be central to any practice-based treatment.
A 42-year-old Caucasian female presented with a two-year history of irritated dry eyes. She noted that her discomfort had gradually worsened over the past two years, which she attributed to being tired.
Refraction revealed mild myopia and astigmatism. She was corrected to RE 6/4.8 LE 6/4.8 in the distance and N4 at near. Reading glasses were prescribed.
Figure 3. After treatment
Figure 4. Extraction of D folliculorum
Slitlamp examination revealed inflamed lid margins with cylindrical eyelash dandruff. Tear break up time was RE 5s LE 4s and fluorescein staining showed mild superficial punctate keratitis. Infrared meibography revealed some meibomian gland atrophy, and eyelash examination with high-magnification microscopy confirmed Demodex.
This patient was diagnosed with Demodex blepharitis and meibomian gland dysfunction. A treatment plan involving practice-based treatments and a take-home regimen was prescribed.
Active tea tree cleaning was performed with BlephEx exfoliation, followed by a passive tea tree gel treatment, warm compression and meibomian gland expression. The patient was given instructions on lid hygiene with eyelid wipes with tea tree oil. At her four-week review, there were no signs of Demodex blepharitis. Tear break up time had improved to RE 12s LE 10s and there were no signs of superficial punctate keratitis.
Figure 5. Meibography
- Liu J, Sheha H, Tseng SCG. Pathogenic role of Demodex mites in blepharitis. Curr Opin Allergy Clin Immunol 2010; 10: 5: 505-510.
- Gao Y-Y, Di Pascuale MA, Li W et al. In vitro and in vivo killing of ocular Demodex by tea tree oil. Br J Ophthalmol 2005; 89: 1468-1473.