Diagnosis of lacrimal punctum lesions using optical coherence tomography: a preliminary study

Evaluation of changes in lacrimal canaliculi width depending on temperature and viscosity of eye drops using spectral-domain optical coherence tomography in dogs

OBJECTIVE

To evaluate the changes in the width of the lower lacrimal canaliculi (LC) upon instillation of artificial tears (AT) at different temperatures and viscosities using spectral-domain optical coherence tomography (SD-OCT).

ANIMAL STUDIED

Eight eyes of four client-owned adult dogs.

PROCEDURES

Imaging of lower LC was performed under general anesthesia. AT at temperatures of 2°C, 20°C, and 38°C, and a high-viscosity tear gel of 20°C, were topically instilled in 100 μL volumes. SD-OCT tracked LC width changes following each instillation.

RESULTS

The average baseline width of the LC was 96.38 ± 30.18 μm. The 2°C AT expanded LC width to 183.50 ± 44.11 μm, returning to baseline in 5.00 ± 1.31 min. The 20°C AT resulted in a width of 155.25 ± 35.79 μm, with a 3.88 ± 1.25 min return. The 38°C AT expanded LC width to 131.75 ± 29.49 μm, with a 2.25 ± 0.89 min return. The high-viscosity tear gel expanded LC width to 208.57 ± 56.31 μm, with remained expanded for 10 or more minutes. In temperature comparisons, the 2°C and 20°C AT significantly expanded the LC width more and had longer return times than the 38°C AT (p < .05). Viscosity comparisons showed higher viscosity eye drops significantly expanded LC width more than lower viscosity eye drops (p < .05).

CONCLUSIONS

This study found that lower temperature and higher viscosity of eye drops had tendency to result in a wider expansion of the LC width. Additionally, the return time to baseline for LC width tended to be longer with eye drops of lower temperature and higher viscosity. This finding could be helpful in advancing future research on tear dynamics.

[Optical coherence tomography in the diagnosis of pathologies of the horizontal portion of the lacrimal drainage system]

This article reviews literature on the use of optical coherence tomography in studying the anatomical structure of the proximal lacrimal drainage system, as well as in diagnosing its pathological changes. Determining the reference values of the parameters of the lacrimal punctum and the lacrimal canaliculus remains an important issue. The review describes the advantages and disadvantages of this method, as well as the prospects for its application in clinical practice.

Evaluation of the upper and lower proximal lacrimal canaliculi using spectral-domain optical coherence tomography in normal Beagle dogs

OBJECTIVE

To confirm the feasibility of visualizing upper and lower proximal lacrimal canaliculi (LC) using spectral-domain optical coherence tomography (SD-OCT).

ANIMALS STUDIED

Eight eyes of four normal Beagle dogs.

PROCEDURES

To obtain an upper proximal LC image, the head was turned in the opposite direction to the eye being imaged, and the medial part of the upper eyelid was everted to expose the LC. To obtain a lower LC image, the lower eyelid was everted just below the punctum. Using "angle mode", the scan line was placed parallel on the long axis of the LC. The inlet LC width (LCW) was measured. Artificial tears (AT) were instilled, and LCW was compared before and after AT instillation. Additionally, the return time to the initial LCW inlet width was recorded.

RESULTS

Before AT instillation, there was a significant difference between the mean upper and lower LCW (91.8 ± 3.2 µm and 110.1 ± 8.4 µm, respectively). After AT instillation, the mean upper and lower LCW were 236.9 ± 27.7 µm and 238.4 ± 30.4 µm, respectively. Significant differences in the LCW before and after AT instillation in both the upper and lower LCWs were observed. The mean return time of the upper and lower LCW to their initial widths after AT instillation was within 4 min.

CONCLUSIONS

Spectral-domain optical coherence tomography was an effective method for providing high-resolution images of the upper and lower proximal LC. This method enables observation of LC changes after instillation of eyedrops in veterinary clinical practice.