Lacrimal pathology evaluated by dynamic lacrimal scintigraphy

Silicone versus collagen plugs for treating dry eye: results of a prospective randomized trial including lacrimal scintigraphy

PURPOSE

To compare the short-term efficacy of collagen and silicone plugs for treating dry eye using quantitative lacrimal scintigraphy.

DESIGN

Prospective randomized clinical trial.

METHODS

In this institutional study, 24 dry eye patients were evaluated in two groups: group I (n = 22 eyes) received collagen plugs and group II (n = 26 eyes) received silicone plugs. Comparisons were made with normal control subjects (n = 22 eyes). Data for the Schirmer I test, tear break-up time, and ocular surface staining with rose bengal dye were recorded before and after punctal occlusion. Lacrimal scintigraphy was performed at each time point, and the time to half maximum activity on the ocular surface (T(1/2)), and the percentage retention of activity on the ocular surface at the end of the dynamic study (RI) were recorded.

RESULTS

In both patient groups, Schirmer I results, tear break-up times, and rose bengal staining scores improved significantly after plug insertion. Mean T(1/2) values and RI values increased significantly in both groups (P < .0001 for both). The differences for these values between groups I and II was statistically insignificant (P > .05).

CONCLUSIONS

Collagen and silicone plugs both resulted in significant increases in aqueous tear volume, half-life of nuclear material on the ocular surface, and percentage of nuclear material retention. The groups' post-insertion values for all parameters were similar. These results suggest that these two plug types have similar efficacy as treatments for dry eye in the short term. Further studies evaluating long-term results are required.

99mTc-diflunisal and the human iris: topical application reveals localization

Following the instillation of a drug into the eye, drainage mechanisms will commence at once. In this report, an attempt was made to assess the dynamics of an instilled nonsteroidal anti-inflammatory drug (NSAID), diflunisal, labeled with 1 MBq 99mTc followed by twenty minutes of scintigraphy. The results obtained with this labeled drug were compared with instillation of the same volume and activity of 99mTcO4-. Although the pertechnetate anion is an excellent and innocuous indicator for detecting the external lacrimal drainage system of the eye, it cannot visualize the internal structures. A clear scintigraphic difference was noted between labeled diflunisal and the pertechnetate anion. Scintigraphic activity surrounding the pupil of the eye provides evidence of visualization of the iris/ciliary body. This seems reasonable as the cyclooxygenase enzyme is located in this structure, and NSAIDs exert their mechanism of action via this complex. With this technology, visualization of some internal structures of the eye may be facilitated.

Lacrimal dacryoscintigraphy

Lacrimal dacryoscintigraphy facilitates definite diagnosis of obstructions and stenosis of the lacrimal drainage system with little stress to the patient. Together with x-ray dacryocystography it is an important diagnostic tool especially for pre- and postoperative evaluation of the drainage apparatus. Dacryoscintigraphy is the best method for measuring the dynamics of tear drainage especially in the canaliculi. Although it is not a substitute for other methods in general use, it complements them and expands their diagnostic accuracy.