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Intraocular pressure control in the first 3 months following trabecular meshwork bypass surgery combined with phaco-emulsification: demographics, underlying diagnosis and outcomes for device type

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First Author: G.Agorogiannis UK

Co Author(s):    A. Vlavianos   S. Georgoulas   J. Clarke              

Abstract Details

Purpose:

To evaluate the changes of intra-ocular pressure in patients with ocular hypertension (OHT) or glaucoma after combined operation of Phaco-emulsification and Insertion of iStent® or iStent inject® trabecular micro-bypass.

Setting:

Glaucoma Service, Moorfields Eye Hospital NHS Trust, UK

Methods:

Parameters analysed were laterality, gender, ethnic origin, age at date of surgery, diagnosis, implant type, mean deviation (MD) of pre-operative 24-2 SITA FAST visual field tests assessed with Humphrey Field Analyser and intraocular pressure (IOP) at time points pre-operatively, 1-7 days, 4-6 weeks, 3 months post-operatively.

Results:

109 patients and 136 eyes were operated for phacoemulsification with iStent® or iStent inject® from Apr 2017 to April 2019. 82 patients underwent one eye surgery and 27 bilateral. Sample was predominantly female (66 patients with 80 eyes), Caucasian (54 patients with 67 eyes) with mean age 75.35±7.75 years (range from 51.88 to 98.22 years). Condition treated was mainly POAG (74 eyes) or OHT (27 eyes). 46 eyes were implanted with the iStent® (GTS100L), 89 with iStent inject® (G2) and in 1 case type of stent wasn't recorded. IOP was found reduced in all time points; mean IOP pre-op was 17.97±5.11mmHg reduced to 15.51±4.66mmHg at 1-7 days (p<.001), 15.30±4.89mmHg at 4-6 weeks (p<.001), 14.31±3.80mmHg at 3 months (p<.001). In patients with advanced glaucoma (MD≤-12dB), no patient had higher IOP at all time points compared to pre-operative pressure. In patients with mild glaucoma (MD≥-6dB) or moderate (-6bB>MD≥-12dB) all patients with preoperative IOPs >20mmHg had favourable outcome regarding IOPs during first and between 4-6 weeks. At 3 months the reduction of IOP in open-angled eyes (n=124, mean IOP reduction -3.7±5.1mmHg) is statistically similar to eyes with angle closure mechanism (n=12, mean reduction -3.0±5.0mmHg).

Conclusions:

At 3 months the reduction of IOP in eyes treated with 2 iStent-inject was lower by 0.9 mmHg compared to the ones with 1 GTS100L (p=0.42). In our cohort study phacoemulsification with iStent® or iStent inject® seems to protect eyes with glaucoma or OHT from any undesired spikes of IOP (due to the operation per se or steroid-induced) during the first 3 months post-operatively, especially in the eyes with advanced damage and/or higher pre-operative IOPs.

Financial Disclosure:

... receives consulting fees, retainer, or contract payments from a competing company