Purpose
Glaucoma tube shunts (TS) are presumed inert following insertion. Novel intraluminal deposits noted in exposed TS of several patients led to an observational study using spectral domain optical coherence tomography (SD-OCT) to characterize these TS deposits.
Methods
Fifteen TS in 11 patients diagnosed with primary open angle, neovascular, aphakic, and uveitic glaucomas underwent 5-line raster anterior segment SD-OCT imaging. Ahmed (n=11) and Baerveldt (n=4) TS were examined. Patients with TS were randomly selected from 2013 to 2014, adults older than 18 years, had light perception or better visual acuity, and no history of retinal surgery with silicone oil. TS were classified as having or not having luminal deposits.
Results
The exposed tubes of two patients had highly reflective intraluminal deposits in the corresponding exposed areas. Six tubes without exposure had a thin rim of highly reflective material. Seven tubes were clear of luminal deposits. The most common diagnosis in the study was uveitic glaucoma in 5 of the 15 eyes (33% with deposits). The next most common diagnosis was primary open angle glaucoma in 4 of the 15 eyes (25% with deposits). The distribution of diagnoses within each group was insignificant for this sample size (p=0.19 deposit, p=0.22 clear). Type of TS was likewise insignificant (p=0.09 deposit, p=0.41 clear). There were 2 non-valved Baerveldt tubes in each group. The mean duration since tube shunt implantation was 15.0 months in the deposit group and 33.7 months in the group without luminal deposits. The majority of patients in each group were using eye drops upon presentation (88.9% deposit, 83.3% clear) and the average intraocular pressure was 20.2 mmHg and 19.0 mmHg in the deposit and the clear groups, respectively.
Conclusions
This study describes intraluminal deposits in tube shunts that may occur as a response to the implanted drainage device. This novel finding suggests that the aqueous tube shunts in glaucoma drainage devices are not inert objects and future studies are needed to examine the functional impact of tube deposits.