Posters

Comparison of induced astigmatism after standard guarded trabeculectomy with MMC and glaucoma drainage device implantation

Poster Details

First Author: M.Zozolou GREECE

Co Author(s):    A. Manaios   D. Tsoukanas   T. Filippopoulos        

Abstract Details

Purpose:

To compare induced astigmatism between guarded trabeculectomy and glaucoma drainage device surgery (GDD) in a tertiary glaucoma referral center.

Setting:

Retrospective, comparative, single surgeon, consecutive interventional case series. Tertiary glaucoma referral center- Athens Vision Eye Institute, Athens.

Methods:

Trabeculectomy and GDD cases operated within the last calender year were identified from surgical log books, one eye per patient was randomly selected. Incusion criteria included Snellen best corrected visual acuity >20/100, spherical equivalent ≤±8D, refractive astigmatism <3D. Exclusion criteria included combined cases, pars plana GDDs and cases associated with delayed post-operative hypotony and/or aqueous leaks requiring additional suturing. Refractive surgically induced astigmatism (SIA), keratometric induced astigmatism and change in spherical equivalent (SE) was compared utilizing vector analysis 3 months after surgery. All outcome measures were correlated with post-op intraocular pressure (IOP), medication requirements and pre-op central corneal thickness (CCT).

Results:

We identified 35 eyes(35 patients) the majority of which (37.1%) had primary open angle glaucoma with an average baseline mean deviation of -14.7±10dB on perimetry. The average pre-op IOP decreased significnatly from 27.7±7.4 mmHg to 12.8±4.1 mmHg (p<0.001) for the trabeculectomy group (n=22) and from 34.4±10.4 mmHg to 15.1±4 mmHg (p<0.001) for the GDD (N=13) group at 3 months. The two groups did not differ with respect to age, pre-op IOP, medication requirements, SE or CCT. The magnitude of the SIA was 1.5±1.1D (median axis 100º) for the trabeculectomy group and 1.2±1.2D (median axis 97º) for the GDD group (p=0.45).

Conclusions:

Trabeculectomy and GDD surgery induce comparable amounts of astigmatism 3 months after surgery. The effect appears not to be fully predictable as there is considerable variability in range and axis. The association between SIA and post-op IOP is weak. FINANCIAL DISCLOUSRE: NONE