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Pouya Alaghband, Elizabeth Angela P Galvis, Michael Madekurozwa, Esmail Eslah, Brian Chu, Darryl R Overby, K Sheng Lim; The effect of Ultrasound cycloplasty (UCP) using High Intensity Focused Ultrasound (HiFU) on aqueous humor dynamics. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1648.
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© ARVO (1962-2015); The Authors (2016-present)
Ultrasound cycloplasty (UCP) is a new procedure utilising High Intensity Focused Ultrasound (HIFU) for treating glaucoma. This study explores the effect of UCP on aqueous humor dynamics in patients with glaucoma.
All subjects attending the glaucoma clinic who had uncontrolled intraocular pressure (IOP) for treated primary open angle glaucoma (POAG) were offered UCP procedure. All UCP procedures were performed under peri-bulbar anaesthesia. Post-operatively, patients were treated topically with steroids for four weeks.All glaucoma treatments were stopped, one month before the baseline and 3 months’ post-operative aqueous dynamic measurements.Inclusion CriteriaAll adult patients with uncontrolled POAG.Exclusion CriteriaPrevious intraocular surgery, except SLT/ALT laserOther types of glaucomaUse of systemic medication such as beta-blockersA history of allergy to fluoresceinOutcome MeasuresIntraocular pressure (Goldmann tonometry)Facility of outflow (Schiøtz tonography)Rate of aqueous flow (fluorophotometry)Uveoscleral outflow (calculated from Goldmann’s equation)
32 patients were recruited into the study. One patient had very high IOP after 2 weeks’ washout and another patient had normal IOP after washout were withdrawn from the study.Uveoscleral outflow was calculated using Goldmann’s equation with an assumed episcleral venous pressure of 10 mmHg.Ft = C (IOP – Pv) + FuTherefore: Fu = Ft – C (IOP – Pv)Fu= Uveoscleral outflowFt = rate of aqueous humor formationC = tonographic facility of outflow IOP = intraocular pressurePv = episcleral venous pressureTable 1. Aqueous humor parameters comparison before and after HiFU treatment
This is the first study investigating aqueous humor dynamics after application of UCP in patients with uncontrolled POAG. We demonstrated that UCP reduced IOP 3-months postoperatively effectively by 14% whilst aqueous flow decreased by 11.3%. Moreover, tonographic outflow facility and calculated uveoscleral outflow remained unchanged.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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