Abstract
Purpose: :
To prospectively evaluate the efficacy, sensitivity and specificity of new confocal microscopy (CM) parameters: meibomian gland acinar longest diameter (MGLD), MG acinar shortest diameter (MGSD), inflammatory cell density (ICD) and MG acinar unit density (MGAUD) in the diagnosis of MGD.
Methods: :
Twenty-one MGD patients (9 males, 12 females) and 27 age and sex matched controls (13 males, 14 females) were recruited. All subjects underwent slit lamp examinations, tear break-up time measurements, vital stainings, Schirmer test, lid meibography, MG expressibility and CM of the lids (HRTII-RCM) and were compared between the two groups by Mann Whitney test. Spearman test was employed to test the correlation between the clinical findings of tear functions, vital staining scores and the four CM parameters. The sensitivity, specificity and cut off value of CM parameters were tested with the ROC technique.
Results: :
The mean tear stability, vital staining scores, MG expressibility and drop out grades were significantly worse in MGD patients compared to controls (p<0.001). The mean values of the MGLD, MGSD, ICD and MGAUD in MGD patients were 85.87±18.27µm, 35.57±10µm, 1044.75±524.03cells/mm2 and 61.82±17.14units/mm2, respectively. These values were significantly worse than those observed in the controls. MGLD:55.97±9.66µm, MGSD:17.40±3.86µm, ICD:62.17±45.52 cells/mm2, and MGAUD:111.76±34.33 units/mm2 (p<0.0001). All CM parameters showed strong significant correlation with MG expressibility and drop out grades.ICD showed significant negative correlation with tear stability and positive correlation with vital stainings. MGAUD showed significant correlation with tear stability and negative correlation with vital stainings. MG diameter values showed significant negative correlation with tear stability and positive correlation with vital stainings. The cut off values for MGLD, MGSD, ICD and MGAUD in the diagnosis of MGD were 65µm, 25µm, 300cells/mm2 and 70units/mm2, respectively. The sensitivity and specificity values of these parameters under these cut off values were 93% and 80% for MGLD, 85% and 98% for MGSD, 100% and 100% for ICD, 85% and 86 % for MGAUD.
Conclusions: :
CM has the potential to diagnose the simple MGD with high sensitivity and specificity. CM based diagnostic parameters correlate significantly and strongly with the status of the ocular surface disease.
Keywords: cornea: tears/tear film/dry eye • imaging/image analysis: clinical • inflammation