Abstract
Purpose: :
To ascertain if a difference in patterns of failure found when comparing the results of subscleral implantation of the Ex-PRESS glaucoma shunt would persist or change in a longer term follow up.
Methods: :
This study sought to examine, in particular, whether the patterns of failure found, when comparing results of subscleral Ex-PRESS shunt implantation in 63 eyes of African American patients and 44 eyes of Caucasian patients followed for an average of 12 months would persist in a longer follow up period.
Results: :
Mean age was 71 and 76 for African American and Caucasian patients respectively. Mean length of follow up was 29 months (12-81) for African American patients and 25 months (12-66) for Caucasian patients.Mean pre-operative IOP was 27 mmHg and 30 mmHg in African American and Caucasian eyes respectively. Mean post-operative IOP was 13mmHg and 12mmHg for African American and Caucasian eyes respectively. Pressure reduction in both groups was significant by the Wilcoxon signed -rank test (p<0.05). In the African American patients, 14 of the 27 eyes that failed, did so in the first year of follow up, with 10 of the eyes failing in the first 6months. Only 2 of the 17 eyes that failed in the Caucasian patients, did so within the first year of follow up, with the majority failing after one year. Mean length of failure was 18.8 months in African American patients and 26 months in Caucasian patients.Using Kaplan- Meier survival curves, the success rates respectively in Caucasian and African American patients were 95% and 84% at 6 months, 95% and 77.6% at 12 months, 84% and 63% at 18 months and 64.4% and 63% at 24 months. The Log- Rank Test for Comparison of Survival Curves indicated a significant difference between the two groups at 6 months and 12 months (p>0.05). The difference between survival curves was not statistically significant at 18 and 24 months.
Conclusions: :
This study shows that patterns of failure between African American and Caucasian glaucoma patients treated with subscleral implantation of the Ex-PRESS glaucoma shunt, change significantly with the passage of time. African American patients fail early while Caucasian patients fail later at a greater pace resulting in a similar survival rate at two years. The possible causes for this pattern are now the basis for an ongoing study by the authors.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • intraocular pressure • wound healing