ex is easier with knowledge of relative sizes for comparison. Adults are distinct, with well-developed head, neck, and legs. The other forms are more difficult to identify. In 1842, Simon identified D. folliculorum to be 0.3 to 0.4 mm long.3 The adult folliculorum average length for both males and females is about 0.286 mm, calculated using Desch measurements. Larva (length, 0.283 mm) is about the same length and width. Protonymph (length, 0.364 mm) is about 25% or one-fourth longer than the adult, with about the same width. Nymph or deutonymph (length, 0.392 mm) are much longer than adults, about 35 to 40% longer and 15 to 20% wider. The size range of 0.3 to 0.4 mm stated by other authors probably includes adults and the larger nymphs (based on Desch findings). Demodex brevis adult average length for males and females is 0.186 mm and about 50% shorter in length than D. folliculorum.
LASH SELECTION AND LIGHT MICROSCOPE VIEWING TECHNIQUES
Sampling the lashes with CD is more likely to yield better results than random epilation.23 Demodex usually resides in compact and opaque CD or deeper in the follicle. Because of this, Demodex can be very difficult to detect. Addition of fluorescein or alcohol has been used to enhance viewing with a microscope of the epilated lash.23,24 Fluorescein solution creates a yellowish contrast and induces instant dissolution and expansion of CD. Together, both properties helped significantly increase detection of mites compared with the time before the fluorescein was added. When the CD is immersed in fluorescein, it becomes semitransparent. This allows better viewing of mite structures within and behind the CD.23
Alcohol is effective in enhancing microscope confirmation of mites present. Gao et al.24,28 found that Demodex embedded in CD could not be counted unless 100% alcohol is added to stimulate them to migrate out. Drawbacks of alcohol were sometimes it could take up to 20 minutes for the mites to become visible. Alcohol can also kill the mite in 3.9 minutes.24,28
Coston11 described the original method of epilation and viewing. He advocated random epilation of four nonadjacent lashes per lid and adding a drop of oil before mounting the coverslip. Gao et al.24 improved the method to epilate lashes with CD, instead of random lashes, and to add alcohol. The method has been further modified by Kheirkhah et al.23 to add fluorescein at the edge of the coverslip11,24 (Table 2; Fig. 2).
The focus of these case reports is detection and diagnosis of the infestation. However, current treatment for this condition includes lid hygiene and tea tree oil lid scrubs and shampoo.5,6,11,12,21,25,29 As stated before, the following cases used the clinical sequence outlined previously.
A 68-year-old woman has been diagnosed with diabetes since 2008 and has been taking oral medications for the condition. The patient complained of dryness all the time and no itchiness or redness. Meibomian gland expression appeared opaque and solid (toothpaste-like) in both eyes. Schirmer test results were OD 10 mm OS 11 mm. There was moderate to severe amount of lid debris (flakes and crusting) in both eyes. There was no debris in the tear film. Diffuse CD was present with less than 10 pieces per eye, as classified by Gao et al.24 (Fig. 3). There was moderate distention of the follicles in both eyes. Lashes were epilated and viewed under a liquid-crystal display microscope (Celestron 44340 LCD Digital LDM Biological Microscope). Demodex was present in both eyes.
Patient 1 Discussion
This case demonstrates severe dryness symptoms but no itching or redness. Based on the observations of Koo et al.,5 less than one-half of Demodex patients have itching or redness. They identified that the most common symptom for Demodex was ocular dryness (74.7%), followed by itching sensation (42.7%), ocular irritation (39.1%), visual disturbance (32.0%), conjunctival injection (9.9%), and glare (3.6%). Schirmer test results were normal. Based on lid expression and the amount of lid debris, a diagnosis of evaporative dry eye or blepharitis could be m