1. iStent with phacoemulsification, n=50
iStent with phacoemulsification A retrospective study of surgeries performed in a tertiary unit serving a diverse ethnic population
Dhakshi Muhundhakumar1, Meena Arunakirinathan1,2, Faisal Ahmed1
1Western Eye Hospital, 2Moorfields Eye Hospital, London, United Kingdom
BACKGROUND
Primary open angle glaucoma (POAG) is the leading cause of blindness globally1; it places huge logisitical and financial demands on healthcare systems worldwide. The mainstay of treatment is control of intraocular pressure (IOP,) through either topical administration of drops, laser treatment or ultimately filtration surgery2. Conventional glaucoma surgery, can involve high failure and complication rates.3
Minimally Invasive Glaucoma surgeries, using devices such as the iStent as an adjunct during cataract surgery, have been shown to succesfully lower IOP with a good safety profile.4 The iStent is a 1mm titanium shunt that inserts into the trabecular meshwork and allows aqueous to drain from the anterior chamber into Schlemm’s canal.
PURPOSE
The iStent is gaining popularity owing to its superior cost analysis, reduction in reliance on topical therapies and a good safety profile.4 This study retrospectively assessed outcomes in a cohort of patients with glaucoma requiring cataract surgery. The following groups were assessed:
iStent with phacoemulsification, n=50
Control group : phacoemulsification alone with no other glaucoma surgery, n = 50
METHODS
The study included adults, over the age of 18 with Open Angle Glaucoma or Ocular Hypertension. Patients with prior glaucoma surgery were excluded. A retrospective review of patient notes was performed, for patients undergoing phacoemulsification with iStent at the Western Eye Hospital from December 2012 to An age matched control group of patients who had phacoemulsification alone over a 3 year period were used for comparison. Average follow up was 18 months. Date was collected on patient demographics, IOP (Goldman applanation), acuity, number of glaucoma medications and mean deviaton on the visual field.
RESULTS
The male female distribution between the groups was 46% male, 54% female. Average age in the iStent group was 75.6 years and in the control group years. Pre-op mean deviation was in the iStent group and in the control.
Chart 1: % change in IOP in each group
Table 1: Pre-op and post-op IOP (mmHg) and number of medications (Meds), with % reduction over the 18 months and p valules.
Chart 2: % change in no. of meds
Table 2:
Complication rates in the iStent and control groups as a %, during 18 months follow up
CONCLUSIONS
Over the 18 month follow up period:
The iStent group showed a statistically significant (p<0.05) reduction in IOP from 17.4mmHg pre-op to 14.5mmHg post-op. In contrast the 9.8% IOP reduction in the control group failed to reach statistical significance.
The iStent group showed a 47.6% drop in medications used, which was statistically significant.
Complication rates were comparable between the two groups, with the episodes of corneal oedema and uveitis in the iStent group resolving with treatment during the follow up period.
REFERENCES
Kapetanakis VV, Foster PJ, Global variations and time trends in POAG: a systematic review and meta-analysis, BJO 2015
Musch DC, Gillespie BW, Lichter PR, Collaborative Initial Glaucoma Treatment Study G, Ophthalmology, vol.115, no.6, pp ,2008
Gedde SJ, Herndon LW, Schiffman JC, Surgical complications in the Tube versus Trabeculectomy study during the 1st year, AJO, vol.143, no.1, pp23-31.e2, 2007
Malvankar-Mehta, Iordanus, iStent with phaco versus phaco alone for pts with glaucoma and cataract: a meta-analysis. PLoS ONE 10(7)