Ophthalmology (Eye & Ear Hospital) - Research Publications

Permanent URI for this collection

http://hdl.handle.net/11343/175

Filters

2001 - 2009 2
Reset filters

Settings
Statistics
Citations
Subject: intraocular pressure ×

Search Results

Now showing 1 - 2 of 2
  • Item
    Thumbnail Image
    Functional Changes in the Retina during and after Acute Intraocular Pressure Elevation in Mice
    Kong, YX ; Crowston, JG ; Vingrys, AJ ; Trounce, IA ; Bui, BV (ASSOC RESEARCH VISION OPHTHALMOLOGY INC, 2009-12)
    PURPOSE: To examine retinal function using the full-field electroretinogram (ERG) during and after acute intraocular pressure (IOP) elevation in wild-type mice. METHODS: IOP was elevated by anterior chamber cannulation in wild-type C57/BL6 mice. The pressure-function relationship was determined by IOP elevation in steps from baseline to 80 mm Hg. The rate of functional recovery was assessed for 60 minutes after an IOP spike of 50 mm Hg for 30 minutes. During and immediately after IOP elevation, scotopic ERG signals were recorded in response to dim and bright flashes (-4.54, -2.23, and 0.34 log cd x s x m(-2)) and analyzed for photoreceptoral (a-wave), ON-bipolar (b-wave), oscillatory potentials (OPs), and scotopic threshold responses (positive [p]STR/negative [n] STR). A full ERG protocol was collected 2 days before and 7 days after the single 50-mm Hg IOP spike. RESULTS: The pSTR was most sensitive to IOP elevation with 50% amplitude loss (mu) at 41 mm Hg (mu, 95% confidence limits (CL): 37.7, 45.6) followed by nSTR at 45 mm Hg (95% CL: 41.0, 49.1). pSTR was significantly more sensitive than the b-wave (95% CL: 41.4, 49.1), a-wave (95% CL: 47.6, 55.3), and OPs (95% CL: 49.6, 59.2). pSTR showed slower recovery immediately after the 50 mm Hg spike compared with the b-wave (P = 0.02). One week after the 50-mm Hg spike, pSTR (-30% +/- 6%, P < 0.001) and OP (-27% +/- 2%, P < 0.001) amplitudes were reduced, whereas other components were unaffected. CONCLUSIONS: The STR in mice is more sensitive to acute IOP elevation and recovers slower than other ERG components. Reduction in pSTR and OP amplitude at 1 week suggests persistent impairment of inner retinal function can occur after a single IOP spike.
  • Item
    Thumbnail Image
    Intraocular pressure before and after cataract surgery in participants of the Melbourne Visual Impairment Project
    Dimitrov, Peter N. ; Mukesk, Bickol N. ; Taylor, Hugh R. ; McCarty, Catherine A. ( 2001)
    The purpose of this study was to investigate the effect of cataract surgery on intraocular pressure (IOP) in a cluster stratified random sample of the population of Victoria, Australia. A total of 3271 participants aged 40 years or older were examined at baseline for the Visual Impairment Project. The baseline study (1992-1994) was followed by a 5-year incidence study. The IOP data were compared between participants who had cataract surgery between the two stages of the study and participants with and without cataract at follow up. The IOP was also compared before and after cataract extraction in glaucoma participants. An eligible 89 non-glaucoma and 24 glaucoma participants had cataract surgery between the two time points. The analyses showed that IOP increases with age in non-operated eyes in both glaucoma and non-glaucoma groups. However, IOP decreased significantly after cataract surgery in eyes with glaucoma but did not change significantly in non-glaucoma participants.