Impression cytology and ocular surface characteristics in patients with seborrhoeic dermatitis

Ocular Manifestations in Seborrheic Dermatitis Epidemiology, Clinical Features, and Management: A Comprehensive Review

Seborrheic dermatitis (SD) often leads to ocular manifestations (OM) that are frequently overlooked. This study comprehensively explains the genesis of these ocular issues, which involves a combination of Malassezia overgrowth, changes in sebum production, and inflammatory responses in the body. The periocular region is rich in sebaceous glands, allowing Malassezia to thrive, which can lead to an inflammatory reaction that spreads to the eye surface, causing disorders such as blepharitis, conjunctivitis, keratitis, and ocular surface diseases. Although epidemiological data are limited, it is well established that ocular involvement occurs in approximately 10%-40% of individuals with SD. Early detection and treatment are crucial to prevent potential vision-threatening complications. A comprehensive diagnostic approach is necessary, including clinical examination, slit-lamp biomicroscopy, tear film analysis, and corneal imaging. Managing these conditions requires a multidisciplinary strategy involving collaboration between dermatologists and ophthalmologists. The treatment should involve topical and systemic medications to address the skin and ocular components. Patient education is critical for improving adherence to therapy, self-management, and the early identification of problems. In the future, it will be essential to investigate the intricate interactions between Malassezia species and host immunological processes. This collective effort will involve creating new biomarkers and diagnostic tools, investigating targeted immunomodulatory drugs and novel lipid-based medicines as potential treatments, and conducting large-scale longitudinal studies to understand the epidemiological patterns and prognostic variables better. By raising awareness, encouraging collaboration across disciplines, and advancing research, healthcare practitioners can significantly improve patients' quality of life with SD and OM.

Biomarkers of ocular surface disease using impression cytology

Impression cytology (IC) is a technique which permits the retrieval of the outermost layer of ocular surface cells via the use of various types of filters. It is a minimally invasive method of evaluating human conjunctival epithelial cell morphology in the diagnosis of dry eye disease, a common and distressing disorder associated with ageing, contact lens wear, autoimmune disorders and refractive (LASIK) surgery. IC may also be utilized in the diagnosis of other ocular diseases, such as keratoconus and thyroid orbitopathy. More recently, IC has been utilized for the subsequent investigation of gene and protein expression of conjunctival cells in order to identify novel diagnostic biomarkers and to further our understanding of the mechanisms underlying ocular surface disease. This review will therefore examine the literature concerning the role of IC in identifying cellular markers of eye disease, systemic diseases with ocular involvement and potential novel therapeutic targets.

Assessment of Consistency in Assignment of Severe (Grade 3) Squamous Metaplasia to Human Bulbar Conjunctiva Impression Cytology Cell Samples

Nucleus-to-cytoplasm (N:C) characteristics of published images of human bulbar conjunctival cells designated as showing severe (grade 3) squamous metaplasia were retrospectively assessed. From publications over a 40-year period, measurements were made from images of cell and nucleus size (based on areas and dimensions) and four different calculations were made for nucleo-cytoplasmic (N:C) ratios. From 54 published images, the mean nucleus-to-cytoplasm area ratio (NU/CYT AREA ratio) was 0.145 +/- 0.077 (range 0.052 to 0.346), compared to two different reference set values of 0.069 +/- 0.017 and 0.080 +/- 0.021. Similarly, a nucleus-to-cytoplasm length ratio (as LNLONG) was 0.308 +/- 0.080 (range 0.191 to 0.475) compared to reference values of 0.226 +/- 0.032 and 0.236 +/- 0.034. Similar differences in reference values were obtained using two other N:C ratio calculations. A wide range of values was found for morphometric N:C indices from published images, especially those without a scale bar, indicating a high incidence of inconsistent grading assignments. Overall, only about 30% of the published images showed morphological features consistent with severe squamous metaplasia (i.e., with the rest neither enlarged nor showing substantially changed N:C ratios) with no substantial pictorial evidence indicating that cells from the human bulbar conjunctiva have pyknotic nuclei. Current evidence indicates that grade 3 squamous metaplasia cells should be substantially enlarged.

Goblet cells of the normal human bulbar conjunctiva and their assessment by impression cytology sampling

Goblet cells of the conjunctiva are the main source of mucus for the ocular surface. The objectives of this review are to consider the goblet cells as assessed by various histological, cytological and electron microscopy methods, and to assess the consistency of published reports (over more than 25 years) of goblet cell density (GCD) from impression cytology specimens from nominally healthy human subjects. Reported GCD values have been notably variable, with a range from 24 to 2226 cells/mm² for average values. Data analysis suggests that a high density of goblet cells should be expected for the healthy human conjunctiva, with a tendency toward higher values in samples taken from normally covered locations (inferior and superior bulbar conjunctiva) of the open eye (at 973 +/- 789 cells/ mm²) than in samples taken from exposed (interpalpebral) locations (at 427 +/- 376 cells/mm²). No obvious change in GCD was found with respect to age, perhaps because the variability of the data did not allow detection of any age-related decline in GCD. Analyses of published data from 33 other sources indicated a trend for GCD to be lower than normal across a spectrum of ocular surface diseases.