RESUMO
PURPOSE: To determine the normative characteristics of corneal subbasal nerves in different age groups using laser scanning in vivo confocal microscopy (IVCM). PATIENTS AND METHODS: This descriptive observational study recruited healthy subjects (aged 20-60 years) from Siriraj Health-Screening Center. Excluded were individuals who had abnormal ocular symptoms, previous ocular surgery, a history of any diseases related to systemic and/or corneal neuropathy, or abnormal corneal sensitivity. Corneal IVCM (HRT3/Rostock Corneal Module) was performed at the central cornea to analyze the subbasal nerve plexus. The corneal nerve characteristics, comprising the number and density of nerves (main nerve trunks, branches, and total nerves) were analyzed using the NeuronJ program, and the corneal nerve tortuosity was graded. The correlations between the subbasal nerve density, tortuosity and age were then analyzed. RESULTS: Eighty subjects were enrolled, with twenty in each of four age groups (20-30, >30-40, >40-50, and >50-60 years). Overall, the mean number and density of main nerve trunks were 27.93±0.81/mm2 and 11.22±0.30 mm/mm2, respectively. As of the nerve branches, the average number and density were 103.56±2.37/mm2 and 9.15±0.30 mm/mm2, respectively. The total nerve density was 20.37±0.39 mm/mm2. There were no significant differences between subbasal nerve parameters of the four age groups. It is noteworthy that 65% of the subjects aged over 40 years revealed high-grade nerve tortuosity. CONCLUSION: The corneal subbasal nerve numbers and densities were not significantly different among a healthy population aged 20-60 years. However, there was a trend towards high tortuosity of the corneal nerve in people aged over 40 years.
RESUMO
PURPOSE: To compare the degree of tear film instability and severity of meibomian gland dysfunction between subjects who use eyeliner and those who do not use eyeliner. METHODS: This cross-sectional study included 42 healthy volunteer women who had no dry eye symptoms (Ocular Surface Disease Index score < 13) and aged between 18 and 40 years. The subjects were classified into 2 groups: an eyeliner-use group (EL: regularly used eyeliner ≥3 d/wk and continuously used ≥6 mo) and a noneyeliner-use group as controls. A questionnaire for ocular surface symptoms using a visual analog scale was administered. Then, a number of eye tests were performed [grading of conjunctival inflammation, fluorescein tear breakup time, ocular surface fluorescein staining, Schirmer I, evaluation of meibomian gland (MG) function, detection of eyelid margin abnormalities, and Demodex detection]. RESULTS: Tear breakup time was significantly lower in the EL group compared with controls (3.0 ± 1.9 vs. 5.8 ± 2.1 s, P < 0.001). MG grading was significantly higher in the EL group than in controls (P = 0.004); higher grade (grades 2-3) was found in 85.7% of EL and 47.6% of controls. Meiboscore was also higher in EL than in controls (P = 0.001). Regarding the morphological changes in lid margin, only telangiectasia was detected significantly more in EL (28.6%) compared with controls (4.8%) (P = 0.041). Conjunctival inflammation was observed 4 times more in EL (66.7%) than in controls (14.3%), P = 0.001. Other outcomes included ocular surface symptoms and fluorescein staining scores, and Schirmer I and Demodex detection were not significantly different between both groups. CONCLUSIONS: The regular use of eyeliner induces tear film instability and MG dysfunction.