Abstract
Purpose :
The purpose of this study is to examine the effect of systemic comorbidities on post-operative intraocular pressure (IOP) and medication burden in patients with ocular hypertension (OHTN) and mild to moderate open angle glaucoma (OAG) that have undergone cataract extraction with trabecular micro-bypass stenting (CE-IS) or cataract extraction alone (CE).
Methods :
This is a retrospective case-control study of 112 consecutive eligible eyes with ocular hypertension or open angle glaucoma that underwent either CE (48 eyes, 31 patients) or CE-IS (64 eyes, 38 patients). Mean IOP and median number of IOP lowering medications for up to one year preoperatively were considered baseline. Failure was defined as inability to either reduce medication burden or decrease IOP by 20% compared to baseline on 2 consecutive visits. The effect of systemic risk factors on time to failure was analyzed using Kaplan-Meier curves, log rank test and Cox proportional hazards models.
Results :
Among all eyes evaluated, the odds of failure were higher CE group when compared to the CE-IS group over the follow up period (p=0.03). In the CE group, hypertension was associated with significantly increased failure when compared to patients without hypertension (p=0.008). However, in the CE-IS group, there was no increased risk of failure among hypertensives compared to non-hypertensives (p=0.51). Diabetes (DM) and hyperlipidemia (HL) did not predict failure in either the CE group (p=0.49 for DM, p=0.49 for HL) or the CE-IS group (p=0.29 for DM, p=0.54 for HL).
Conclusions :
It is well known that cataract surgery alone is an effective method of lowering IOP, however the mechanism of IOP lowering is incompletely understood. We found that systemic hypertension was a risk factor for failure of cataract surgery alone to reduce IOP and medication burden in eyes with OHTN or mild to moderate OAG. However, hypertension was not found to be a risk factor for failure among eyes that underwent iStent implantation with cataract surgery. Further investigation is warranted to elucidate the interaction between blood pressure and anti-hypertensive medications and the changes in aqueous outflow pathways after CE and CE-IS.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.