Dr William Trinh
BOptom BSc OD
Demodex blepharitis is frequently encountered in ophthalmic practices and often associated with other ocular surface diseases.1 As this case report shows, it can be easily and effectively managed in any optometry practice.
A 74-year-old male presented to the practice, reporting that his eyes had often been itchy and irritated in the past few months, despite using Genteal eye-drops three or four times daily. The patient had an unremarkable medical history and did not take any systemic medications. His ocular history included mild bilateral cataracts and right eye posterior vitreous detachment.
On examination, his best corrected visual acuity was 6/12 R and 6/9 L, and intraocular pressures were 14 R and 13 L. Anterior examinations revealed numerous collarettes, which had the appearance of clear yellow cylindrical dandruff attaching to the eyelid margin and encircling the eyelashes (Figures 1 and 2). The condition was worse in the upper eyelid in both eyes, with moderately injected eyelid margins. Bulbar and tarsal conjunctivas were quiet and there was no superficial corneal erosion observed. There were moderate anterior cataracts, worse in the right eye.
Figure 1. Right eye, day 1
Figure 2. Left eye, day 1
The patient was diagnosed with Demodex blepharitis and was given information regarding the treatment, which involved tea tree oil in office. The patient’s consent was provided. Treatment of Demodex blepharitis was initiated with one drop of proparacaine into the conjunctiva fornix to reduce the irritation and burning sensation prior to applying tea tree oil (TTO) to the roots of upper and lower eyelashes with a cotton bud. The patient was instructed to close his eyes for five minutes.
After this period of time, the patient’s eyelids were then re-examined and all the melted collarettes were wiped off with a fresh cotton bud. One drop of Prednefrin Forte 1% was instilled into the conjunctiva fornix to reduce the hyperaemia and the patient was prescribed hydrocortisone 1% ointment applied to the lid margins at night time and advised to continue Genteal eye-drops. At one week follow up, the patient no longer reported any symptoms of itchy or irritated eyes. On examination, there were no visible collarettes detected and the eyelids and conjunctiva were quiet (Figures 3 and 4).
Figure 3. Right eye, post 7 days
Figure 4. Left eye, post 7 days
Demodex blepharitis is one of the most common ocular conditions seen in eye-care practices. Most literature reviews show about 30 per cent2,3 of all patients who come to see eye care practitioners have Demodex blepharitis and they are often associated with meibomian gland dysfunction (MGD), anterior blepharitis, vulgaris acne and rosacea.4 Demodex blepharitis is found more commonly in the older population5 and in nursing home environments.
Demodex blepharitis is caused by Demodex mites infecting the eyelid. Demodex mites are eight-legged ectoparasites that can live inside the lash of sebaceous glands and meibomian glands. Studies have shown that Demodex mites usually migrate from a patient’s face to the eyelid margins due to the increased sebum secretion from the meibomian glands.6
If Demodex blepharitis is left untreated, it can cause symptomatic blepharokerotoconjuntivitis such as chronic dry, itchy, irritated, gritty, stinging, burning, watery and red eyes. Therefore, to provide effective treatment it is important for eye-care practitioners to be familiar with Demodex blepharitis and associated conditions in order to provide accurate differential diagnosis and effective treatment
Demodex blepharitis can be easily and differentially diagnosed from other types of blepharitis on clinical examination by the appearance of cylindrical collarettes, which are made up of oil, eggs and dead skin. It is possible to extract the mites for slide microscopic examination, but this is generally regarded as unnecessary and time-consuming in the clinical setting.
To eliminate or improve Demodex blepharitis, it is required to eliminate or reduce the Demodex mite population on eyelids by physical removal, chemical killing or oxygen deprivation while also improving the skin condition on the eyelids by lid hygiene and anti-inflammatory medications.
In mild cases of Demodex blepharitis without symptoms, daily routine eyelid hygiene and warm compress are sufficient. In mild cases of symptomatic Demodex blepharitis, chloramphenicol ointment or hydrocortisone ointment should be added, depending on the associated other anterior or posterior blepharitis. In moderate to severe cases of Demodex blepharitis, TTO should be applied to eliminate the Demodex mites effectively.7
The exact mechanism of TTO on killing demodex is unclear; however, it is believed TTO compromises the mites cytoplasmic membrane, has an anti-inflammatory property and anti-cholinesterase activities.8
One hundred per cent TTO concentrated can be obtained from a local pharmacy and can be used in the practice as one-time treatment for patients. Commercially prepared TTO wipes (Cliradex terpinen 4-ol or Blephadex) can be prescribed for patients, especially for children, to use twice daily at home for one month. However, moderate-to-severe cases of demodex may require the TTO to be at full strength to be an effective agent as described in this case. The killing effect of TTO demodex mites is dose-dependent; 100 per cent, 50 per cent, 25 per cent and 10 per cent of TTO completely kills demodex mites in 3.7 minutes, 14.8, 34.7 and 150 minutes, respectively.9
The incidence of toxicity keratitis from 100 per cent concentrated TTO is generally not encountered as the TTO is applied only to the outer eyelid margins. Mild lid allergic reactions can occur in some patients and can be treated easily with topical steroids. The possibility of chemical irritation of TTO can be further reduced by the use of disposable bandage contact lenses during the in-office procedure.
As with most chronic conditions, the recurrence of Demodex blepharitis is almost inevitable so regularly-scheduled eye examinations are very important.
Demodex blepharitis is a common yet easily-overlooked ocular condition encountered in ophthalmic practices. Optometrists’ awareness and sound knowledge of Demodex blepharitis are important. A simple but effective treatment can be applied to manage the condition and improve our patients’ quality of life.
- Gao YY, Di Pascuale M, Li W et al. High prevalence of Demodex in eye lashes with cylindrical dandruff. Invest Ophthalmol Vis Sci 2005; 46: 3094-3098.
- Kemal M et al. The prevalence of Demodex folliculorum in blepharitis patients and the normal population. Ophthalmic Epidemiology 2005;12: 287-290.
- Lemp MA, Nichols KK. Blepharitis in the United States 2009: a survey-based perspective on prevalence and treatment. Ocul Surf 2009; 7: S1–S14.
- Bernardes TF, Bonfioli AA. Blepharitis. Semin Ophthalmol 2010; 25: 79-83.
- Roth AM. Demodex folliculorum in hair follicle of eyelid skin. Ann Ophthalmol 1979; 11: 37-40.
- Coston T. Demodex folliculorum blepharitis. Trans Am Ophthalmol Soc 1967; 65: 361-392.
- Tighe S et al. Terpinen 4 ol is the most active ingredient of tea tree oil to kill Demodex mites. Transl Vis Sci Technol 2013; 2: 7: 2.
- Mills C et al. Inhibition of acetylcholinesterase by TTO. J Pharm Pharmaco 2004; 56: 375-379.
- Gao Y et al. In vitro and in vivo killing of ocular demodex by TTO. Br J Ophthalmol 2005; 89: 11: 1468-1473.