Most patients under routine glaucoma care demonstrate slow rates of visual field progression. The MD rate in the current study was similar to an interventional prospective study, but considerably less negative compared to published studies with similar design.

We describe a complication of posterior chamber phakic intraocular lens (PCP IOL) implantation for high myopia. Both eyes of a 44-year-old patient were treated prophylactically with a neodymium:YAG laser iridotomy before PCP IOL implantation. Bilateral PCP IOL implantation was performed uneventfully, although a peripheral iridotomy was required immediately after implantation in the right eye because of early pupillary block glaucoma. Two months later, the left eye developed pupillary block glaucoma despite apparently patent iridotomies. The PCP IOLs were subsequently removed.

Membrane potential and ionic currents were studied in cultured rabbit retinal pigment epithelial (RPE) cells using whole-cell patch clamp and perforated-patch recording techniques. RPE cells exhibited both outward and inward voltage-dependent currents and had a mean membrane capacitance of 26 +/- 12 pF (SD, n = 92). The resting membrane potential averaged -31 +/- 15 mV (n = 37), but it was as high as -60 mV in some cells. When K+ was the principal cation in the recording electrode, depolarization-activated outward currents were apparent in 91% of cells studied. Tail current analysis revealed that the outward currents were primarily K+ selective. The most frequently observed outward K+ current was a voltage- and time-dependent outward current (IK) which resembled the delayed rectifier K+ current described in other cells. IK was blocked by tetraethylammonium ions (TEA) and barium (Ba2+) and reduced by 4-aminopyridine (4-AP). In a few cells (3-4%), depolarization to -50 mV or more negative potentials evoked an outwardly rectifying K+ current (IKt) which showed more rapid inactivation at depolarized potentials. Inwardly rectifying K+ current (IKI) was also present in 41% of cells. IKI was blocked by extracellular Ba2+ or Cs+ and exhibited time-dependent decay, due to Na+ blockade, at negative potentials. We conclude that cultured rabbit RPE cells exhibit at least three voltage-dependent K+ currents. The K+ conductances reported here may provide conductive pathways important in maintaining ion and fluid homeostasis in the subretinal space.

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