Purpose. To evaluate potential risk factors for developing tube shunt exposure in glaucoma patients. Patients and Methods. Forty-one cases from 41 patients that had tube shunt exposure from 1996 to 2005 were identified from the Robert Cizik Eye Clinic and Bascom Palmer Eye Institute. Each case was matched with 2 controls of the same gender and with tube shunts implanted within 6 months of the index case. Conditional logistic regression was used to determine risk factors. Results. The study cohort includes a total of 121 eyes from 121 patients. The mean age was 63.6？±？19.7 years, ranging from 1 to 96 years. The average time to exposure was 19.29？±？23.75 months (range 0.36–85.74 months). Risk factors associated with tube exposure were Hispanic ethnicity ( ; OR？=？3.6; 95% CI, 1.3–9.7), neovascular glaucoma ( ; OR？=？28.5; 95% CI, 2.6–316.9), previous trabeculectomy ( ; OR？=？5.3; 95% CI, 1.6–17.7), and combined surgery ( ; OR？=？3.7; 95% CI, 1.1–12.7). Conclusions. Hispanic ethnicity, neovascular glaucoma, previous trabeculectomy, and combined surgery were identified as potential risk factors for tube shunt exposure. These potential risk factors should be considered when determining the indication for performing tube shunt implantation and the frequency of long-term followup. 1. Introduction Tube shunts have historically been used to treat glaucoma in cases that are refractory to filtering surgery or in those where filtering surgery is unlikely to be successful. In recent years, the indications have broadened, with some clinicians advocating shunts as primary surgical treatment for advanced glaucoma [1]. The overall use of tube shunts has been steadily increasing over the past decade, with one study showing an annual increase in the number of shunts placed between the years of 1995 and 2004 totaling 184% [2]. These devices function by draining aqueous through a silicone tube to a reservoir plate, which is covered by Tenon’s capsule and conjunctiva. The tube is generally covered by one of a variety of patch materials where it enters the eye to prevent exposure through the overlying tissue. Such exposures may lead to more serious complications, such as endophthalmitis, if not promptly identified and treated [3]. The Tube versus Trabeculectomy and Ahmed Baerveldt Comparison studies reported the incidence of tube exposure as 5% at 5 years of followup and 1% at 1 year of followup, respectively [4, 5]. The specific causes of tube exposure, however, have not been clearly elucidated in the literature. Byun et al. concluded that the number of previous ocular surgeries
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