Tear meniscus level as an indicator of nasolacrimal obstruction.

PURPOSE: To quantitate the normal level of the tear meniscus, and to determine whether it is an accurate diagnostic indicator of nasolacrimal drainage obstruction.

METHODS

We performed a retrospective, controlled, case series study on patients evaluated from 2000 to 2002 for epiphora. The height of the tear meniscus was measured using the slit lamp by one experienced observer. Nasolacrimal outflow status was assessed by probing and irrigation. Patency on the nontearing eye was also confirmed by probing and irrigation, and the corresponding tear meniscus levels comprised one control group (59 sides of 62 patients). Tear meniscus levels in patients with ptosis or dermatochalasis without epiphora comprised the second control group (78 sides of 39 patients). The 2 control groups were combined to determine the normal tear meniscus level and ratio between the two sides. The control tear meniscus levels and ratios in patients without epiphora were compared with the tear meniscus levels and ratios in patients with nasolacrimal obstruction (65 sides of 62 patients).

RESULTS

The 2 control groups examined did not statistically differ with respect to tear meniscus height (P = 0.06). The control median tear meniscus level (0.2 mm) significantly differed from the obstructed median tear meniscus level (0.6 mm) (P<0.0001). The control median ratio between the two sides (1.0) significantly differed from the obstructed ratio (2.5) (P<0.0001). The absolute tear meniscus level and the tear meniscus ratio were both accurate indicators of obstruction. The percent change in absolute tear meniscus level after lacrimal surgery was -58.3%.

CONCLUSIONS

To our knowledge, a quantitative analysis of the tear meniscus height has not been previously documented in the literature. Patients with nasolacrimal system stenosis or obstruction have elevated tear meniscus levels and ratios relative to control subjects. The absolute tear meniscus level and ratio tests are excellent diagnostic indicators of nasolacrimal obstruction and its resolution after successful lacrimal surgery.