Abstract
Purpose: :
To prospectively investigate the effect of intraocular pressure (IOP) reduction following glaucoma surgery on optic nerve head topography and retinal nerve fiber layer (RNFL) thickness.
Methods: :
Patients meeting eligibility criteria with medically uncontrolled glaucomatous optic neuropathy requiring trabeculectomy or aqueous drainage device implantation were prospectively recruited. Eyes with visual acuity less than 20/40 or visual field mean deviation less than -20dB, history of prior intraocular surgery, ocular disease other than glaucoma, or unreliable standard automated perimetry (SAP) were excluded. All patients underwent complete ocular examination, blood pressure, SAP, optical coherence tomography (OCT), scanning laser polarimetry (SLP) and confocal scanning laser ophthalmoscopy (HRT) prior to surgery and at the two-month postoperative visit. A paired samples Student’s T-test was used for the analysis.
Results: :
Twelve patients (mean age 70.5±11.3 years, average SAP mean deviation 6.9±7.7 dB) were enrolled. The mean post-operative IOP (12.8±7.6mmHg) was significantly (p= 0.004) reduced compared with mean pre-operative IOP (19.0±6.4 mmHg). The mean post-operative HRT rim area and volume (1.06±0.30mm2 and 0.23± 0.10mm3) significantly increased (p=0.02 and 0.04) compared with mean pre-operative values (0.97±0.26mm2 and 0.19±0.08mm3). The mean superior, inferior and average RNFL thickness measured using OCT and SLP showed no change (p>0.8). No significant change (p>0.08) was observed in systolic, diastolic, or mean ocular perfusion pressure.
Conclusions: :
Although RNFL thickness measures remain stable following surgical IOP reduction, assessments of the neuroretinal rim significantly increase requiring creation of a new baseline topography map.
Keywords: intraocular pressure • imaging/image analysis: clinical • optic nerve