ade. Because the Schirmer test results were normal for this patient, aqueous deficient dry eye could be ruled out. However, a closer examination of the lids reveals a diffuse amount of CD, pathognomonic for Demodex, along with the lid debris. As mentioned previously, literature points to the link between MGD and blepharitis with Demodex.14,20
Three studies have associated diabetes with Demodex infestation.30–32 Yamashita et al.30 studied 42 patients in each group (control and Demodex). They found no statistically significant differences between the control and diabetes groups with regard to age and sex in both groups (p > 0.05). Demodex folliculorum was significantly more prevalent in diabetic patients (27.4%) than in control patients (19.0%).30 Clifford and Fulk32 analyzed the prevalence of Demodex on 256 subjects and also concluded that mites were more abundant in patients with diabetes. Akdeniz et al.31 found a significantly higher mean mite density and bigger mite mean size on cheek biopsy of diabetic patients compared with a control group. Both Yamashita et al.30 and Clifford and Fulk32 examined lash follicles, whereas Akdeniz et al.31 did not. The relationship between diabetes and Demodex has been theorized as a result of peripheral vascular insufficiency. Persons with diabetes may have a reduced ability of their immune systems to control mites because of vascular insufficiency.31–33
In contrast, Lee et al.6 found no relationships between Demodex in lashes and systemic diseases such as diabetes and hypertension. The number of subjects with diabetes was not stated. Lee et al.6 mention the study by Forton et al.,33 where 96% of their Demodex patients were healthy. Forton et al.33 only found three patients with diabetes in his Demodex sample of 115 patients. Forton et al.33 did not study lash follicles but found Demodex by skin biopsy.6,33
A 44-year-old Hispanic man presents with moderate to severe dry eye. The patient reported the frequency of dryness and redness to be sometimes (mild). Meibomian gland expression appears clear to mildly opaque, few particles, low viscosity. The cornea was clear in both eyes. There was mild bulbar conjunctival injection and a diffuse amount of CD present in both eyes. The lids appeared to be mildly greasy, with a mild amount of distention at the base of the lashes. Epilation of two lashes from each upper lid reveals Demodex present. On one follicle, the microscope at 10× showed D. brevis (Fig. 4).
Patient 2 Discussion
Of the two species in humans, D. brevis is not commonly seen in the general population. Demodex brevis normally resides singly in the sebaceous and meibomian glands.14 Because the mite is not usually found on the lash follicles, detection after epilation is rare.3 Gao et al.24 reported that five of 422 epilated specimens were D. brevis. According to Tseng, the prevalence of D. brevis is 9.1%.14 From an eye care practitioner’s point of view, D. brevis may be rarely seen and may require more lashes to be epilated.19 But, in the big picture outside the lids, D. brevis does inhabit a larger area of the human body compared with D. folliculorum.26
In 1963, Akbulatova first identified D. brevis.3,22 Demodex brevis is typically smaller than D. folliculorum and has a spindle shape and stubby legs.3 Demodex brevis presence is much higher in patients who developed corneal lesions, such as peripheral and nodular scarring, vascularization, and central opacities.3,14 Because D. brevis primarily resides in meibomian glands, the inflammation has greater proximity and might more easily reach the conjunctiva and the cornea.19 In this case, the patient did not have any corneal abnormalities.
A 40-year-old white woman presented with a history of allergies and dry eyes. There was MGD present (opaque or many particles with medium viscosity) in both eyes and inferior nasal and temporal lissamine green staining in the right eye. The right eye also had grade 1 corneal infiltration in the peripheral cornea. Closer examination of the lids revealed CD (diffuse amount; greater than 10 pieces per eye