Abstract
Purpose: :
Conjunctival impression (CI) is an accepted, minimally invasive technique for harvesting the most superficial layer of the conjunctival epithelium. It can be used to support the diagnosis of ocular surface disorders (OSD), the monitoring of their treatment, and the investigation of their etiology.Current CI method is neither obvious nor easy a procedure that remains operator-dependant, in spite of various attempts of improvement. The prevalent method is relatively cumbersome and time-consuming for a clinician within the scope of routine daily use. Furthermore, due to its variable and irregular sampling, it is not effectively compatible with the development of quantitative analytical tools to analyse biomarkers on collected cells, despite the availability of modern techniques, such as FCM, PCR or ELISA. For that purpose, we have developed and evaluated EYEPRIM®, a new single-use device for reliable and effective CI.
Methods: :
Conjunctival epithelium of pigmented rabbits was sampled either using the EYEPRIM device equipped with 69sq.mm Polysulfone 0.2µm membranes or by applying manually a 63sq.mm similar membrane. Left Eye (LE) and Right Eye (RE) superotemporal quadrants were collected with both techniques. The other three quadrants were collected on both eyes using EYEPRIM. Superotemporal quadrants were also collected with EYEPRIM by trained and candid operators. Membranes were stained with PAS-Hematoxylin, and cells counted at 3 locations per sample on a 170µmx133µm area using confocal microscopy.
Results: :
On average, EYEPRIM collected 55% more cells than the current CI method. For all EYEPRIM groups, we achieved a mean sampling of 17 500 (SD 3100) cells/sqmm. No significant difference was noted between the LE and RE quadrants collected with EYEPRIM. Cell counts in the infero-temporal quadrant were lower than in the other quadrants, likely due to nictitating membrane in the rabbit eye: InferoTemporal 367 (SD 78), InferoNasal 296 (SD 93) SuperoTemporal 417 (SD 53) SuperoNasal 376 (SD 68), per 0.023sqmm.
Conclusions: :
These results evidence the efficiency of EYEPRIM to collect cells from conjunctival epithelium. By controlling both the application surface and pressure, EYEPRIM demonstrated a performance and repeatability higher than those of the current CI method. EYEPRIM cell collection device improves the CI procedure and may offer new possibilities for the quantitative exploitation of CI.
Keywords: cytology • conjunctiva • flow cytometry