The iStent trabecular micro-bypass stent reduces post cataract surgery IOP spikes in advanced glaucoma

Session Details

Session Title: Glaucoma

Session Date/Time: Monday 09/10/2017 | 08:00-10:30

Paper Time: 09:18

Venue: Room 4.1

First Author: : G.Moussa UK

Co Author(s): :    P. Pandey   S. Begum   I. Masood              

Abstract Details

Purpose:

Cataract surgery in patients with advanced glaucoma is fraught with risk. The trabecular meshwork in such patients has a far less reserve and therefore this group of patients can suffer with higher post-­‐operative IOP spikes leading to pain, corneal oedema, glaucomatous nerve damage or anterior ischemic optic neuropathy, further visual field loss and loss of fixation. We present data, which demonstrate that the iStent is extremely useful in blunting the post-operative IOP spike following cataract surgery in moderate to advanced glaucoma.

Setting:

Data was collected in a tertiary referral centre in the West Midlands,at Birmingham Midland Eye Centre

Methods:

A non-comparative case series where data was collected prospectively on patients with moderate to advanced glaucomatous optic neuropathy. Sixty-six consecutive cases were identified (26:40 male F:M, Mean age 76.0 years). Eighteen had advanced glaucoma. Following routine clear corneal temporal section phacoemulsification followed by implantation of 1-2 iStents depending on the target IOP in the nasal quadrant Schlemm canal. IOP readings were checked 2 hours post operatively and then 24 hours post operatively. All patients were prescribed a stat dose of Diamox 250mg immediately after surgery. Statistical analysis was performed with SPSS Version 23.0 statistic software package.

Results:

Sixty-six eyes from 59 patients (26:40-female:male,mean age 76.0years,SD±9.9). Mean IOP; pre-operatively 23.0mmHg(SD±7.1), immediately post-operatively 19.0mmHg(SD±9.4), 1-day post-operatively 14.9mmHg(SD±6.6) significant using Wilks’ Lambda Multivariate Analysis of Variance was significant (MANOVA), p=7*10^-8). Difference in mean IOP pre-operatively and immediately post-operatively was significant (paired t-test,p=0.004). No complications reported. Percentage of patients with 2-hour postop IOP<15mmHg, 42.4%. IOP<21 mmHg,66.7%. IOP<25 mmHg,72.7%. IOP<30 mmHg,86.4%. IOP<35mmHg 98.5%. One IOP spike reported at 55mmHg. No statistical significance was found between immediately post-operative IOP between one iStent(n=18,mean=19.1,SD±8.2) and two iStents(n=44,mean=18.9,SD±10.2) (independent samples T-test p=0.944).

Conclusions:

The majority of patients did not suffer a significant IOP spike. This was despite borderline IOP in a number of patients with vulnerable optic discs. Two hours postoperative IOP was statistically significantly lower than preoperative. In the past, many of these patients would have required combined cataract and filtering surgery but now they can be managed successfully with iStent implantation at the time of cataract surgery, a procedure with an extremely favourable risk profile. The iStent may have great value in managing such complex cases.

Financial Disclosure:

NONE