Dacryoscintigraphy in Measurement of Tear Clearance in Patients With Meibomian Gland Dysfunction
Narrative Responses:
Purpose
To measure tear-clearance in Meibomian Gland Dysfunction (MGD) patients with a dynamic nuclear medicine method, dacryoscintigraphy (DSCI).
Methods
36 patients were examined including 14 healthy volunteers and
22 MGD patients. One drop of a solution with 10 MBq 99mTc sodium pertechnetate was instilled with a micropipette into the lacrimal lake of both eyes. Measurements were performed according to a dynamic data acquisition protocol, which resulted in summed DSCI images. Data were also evaluated in special regions of interest (ROIs) separately, and consecutive time activity curves were created. Tear break up time (TBUT) and Schirmer I test were also performed prior to DSCI measurements. Tear clearance (T ½) values were calculated based on the activity curves.
Results
The clearance (T ½) values were 6.38 min (SD±1.9) in MGD patients and 29.78 (SD±8.28) in normal controls, respectively. The difference was significant (p<0.01). Schirmer I test values were 7.35 (SD±4.96) in MGD patients and 16.28 (SD±8.62) in the control group. TBUT values were 5.36 (SD±2.62) in MGD patients and 15.15 (SD±2.38) in normal patients.
Conclusion
Tear clearance values were significantly higher in MGD patients than is normal volunteers, which may be the result of increased drainage of tear from the eyes towards the nasal cavity in MGD patients. The reasons for increased drainage in MGD patients without reflex tearing are yet to be investigated.