A placebo-controlled, double-masked evaluation of mitomycin C in combined glaucoma and cataract procedures.

PURPOSE: This study was performed to determine if adjunctive use of mitomycin C (MMC) would increase the success of combined phacoemulsification, intraocular lens implantation, and trabeculectomy surgery with releasable sutures. METHODS: Seventy-two eyes with cataract and glaucoma, requiring surgery for decreased vision, uncontrolled intraocular pressure, or to obtain a better view of the optic nerve, were randomized to receive a 2.5-minute subconjunctival exposure to either MMC (0.5 mg/ml) or placebo balanced salt solution. Postoperative evaluations at 3, 6, and 12 months were performed by a masked observer who recorded visual acuity, intraocular pressure, glaucoma medications, presence of filtering blebs, and complications. Endothelial cell counts were measured before and 3 months after surgery. RESULTS: The MMC group had significantly greater reduction in mean intraocular pressure through the first 12 months of follow-up (7.05-7.65 mmHg versus 2.62-3.84 mmHg; P = 0.001-0.028). In addition, through the first 6 months of follow-up, the MMC group required significantly fewer medications (0.4-0.5 versus 1.1-1.2; P = 0.002-0.004). Requirements for additional glaucoma surgery were less in the MMC group (4/ 36) than in the placebo group (7/35) (P = 0.301). Filtering blebs were significantly larger at 6 and 12 months (P = 0.002 and P = 0.001, respectively), and would leaks were more common (P = 0.101) in the MMC group. The mean decrease in endothelial cell count at month 3 was slightly, although not significantly, greater in the MMC treatment group (206.9 versus 91.3 cells/mm2* P = 0.377). CONCLUSION: The increased success of the glaucoma procedure in the MMC group together with relatively minor toxicity, suggests its use is beneficial in combined glaucoma-cataract surgery.

Surgical management of a long-standing subfoveal neovascular membrane secondary to ocular histoplasmosis.

Subretinal neovascular membranes located under the fovea typically lead to significant visual loss. Laser treatment has been limited due to the anatomic location of the neovascular process, but surgical removal has been reported with promising results. We surgically removed a long-standing, presumed ocular histoplasmosis syndrome (POHS) subfoveal neovascular membrane that had been present for 10 months in a patient's only functional eye, with unexpected good results. This case suggests that the good visual outcomes achieved by surgically excising smaller subfoveal neovascular membranes early in their natural history also can be achieved in selected patients with more chronic and severe subfoveal neovascular processes.

Temporal arteritis. Aggressive treatment prevents visual complications.

Visual loss is the most common complication of temporal arteritis when the disease is misdiagnosed or undertreated, yet treatment recommendations vary among different medical disciplines. In this article, Dr Wind presents a case report and information from the medical literature illustrating different treatment regimens and visual outcomes in patients with temporal arteritis.

Effects of Ca++ depletion on lens equatorial currents in frog lenses.

The combination of the vibrating probe measuring the outward equatorial current (J) with microelectrodes measuring PD and the response to injected current provides one of the best means of relating macro findings of lens currents to the micro data that have been reported using the patch clamp technique. In standard frog Ringers solution the equatorial current appears to be a relatively pure K+ current with a reversal potential of -95 mV. This agrees with the reversal potential of the 45 pS K+ channel. When Ca++ is removed from the medium bathing the lens the input resistance (R) decreases, the PD becomes less negative and the current J increases. This process can be reversed by adding Ca++ or Mn++ to the Ca++ deficient medium. When all Ca++ is removed from the medium by adding EGTA in the absence of Ca++, the increase in J is less than expected. However, if Na+ is replaced by TMA in the Ca++ depleted EGTA medium the current is seven times as great. These changes are consistent with those found in non-selective cation channels in the absence of Ca++.

Effect of ouabain on lens equatorial currents.

The equatorial potassium current measured with the vibrating probe is a segment of the potassium electrical loop. The equatorial current, J, was measured simultaneously with the PD and with the response to an injected current, I. The injection of sufficient inward current, I, made the PD more negative and increased the electrical gradient so that the current J became zero. The PD at which this occurs (PDJ-0) is the reversal potential. Following treatment with ouabain, the PD and PDJ-0 both become less negative. Since the driving force for the current, J, is equal to the difference between PD and PDJ-0, J may increase, stay the same or decrease depending on the relative changes in PD and PDJ-0. In the presence of ouabain, the PDJ-0 changes in parallel with or more rapidly than the PD.

Equatorial potassium currents in lenses.

Earlier work with the vibrating probe demonstrated the existence of outward potassium currents at the equator and inward sodium currents at the optical poles of the lens. By adding microelectrodes to the system, it is possible to relate steady currents (J) to the potential difference (PD) measured with a microelectrode. By injecting an outward current (I), it is possible to determine resistances and also the PD at which the steady outward potassium current becomes zero (PDJ = 0). At this PD the concentration gradient for potassium efflux and the electrical gradient for potassium influx are balanced so that there is no net flow of potassium across the membranes associated with the production of J. The PDJ = 0 for 18 rat lenses was 86 mV and that for 12 frogs lenses was -95 mV. This agrees with the potassium equilibrium potential and provides strong evidence to support the view that the outward equatorial current, J, is a potassium current. With the injection of outward current, I, the PD becomes more negative, the outward equatorial current, J, decreases, and the inward current at the optical poles increases. This suggests that there are separate electrical loops for K+ and Na+ that are partially linked by the Na, K-pump. Using Ohm's law, it is possible to calculate the input resistance (R = delta PD/I), the resistance related to the production of J (RJ = delta PD/delta J), and the effect of the combined resistances (delta J/I). The driving force for J can be estimated (PDJ = 0-PD). The relationships among currents, voltages and resistance can be used to determine the characteristics of the membranes that are associated with the outward potassium current observed at the equator. The effects of graded deformation of the lens were determined. The effects were reversible. The sites of inward and outward currents were not altered. Following deformation, the equatorial current, J, increased, and the PD became less negative. The PDJ = 0 remains the same so the ratio of K+ concentrations across the membrane responsible for J is unchanged. Therefore, the decrease in PD is ascribed to an increase in Na+ permeance with a resultant increase in driving force accounting for the increase in J.

Pulsed Doppler assessment of left ventricular diastolic filling in coronary artery disease before and immediately after coronary angioplasty.

To determine if left ventricular (LV) diastolic filling abnormalities are detectable by Doppler echocardiography in patients with coronary artery disease (CAD), 34 patients with CAD and 24 normal, age-matched control subjects underwent mitral valve pulsed Doppler examination. At catheterization, all CAD patients had typical angina, at least 70% diameter narrowing of 1 major coronary artery, ejection fraction of 50% or more and no valvular heart disease. Seventeen CAD patients underwent coronary angioplasty and had a Doppler examination 1 day before and 1 day after the procedure. Doppler diastolic time intervals, peak velocities at rapid filling (E velocity), atrial contraction (A velocity) and the ratio peak E/peak A velocities were measured. The following areas under the Doppler velocity envelope and their percentage of the total area were calculated: first third of diastole (0.33 area), triangular area under the peak E velocity (E area), and triangular area under the peak A velocity (A area). Patients with CAD and normal subjects were significantly different (p less than 0.01) in peak E velocity (CAD 0.60 +/- 0.12 m/s, normal 0.68 +/- 0.12 m/s), peak A velocity (CAD 0.59 +/- 0.12 m/s, normal 0.48 +/- 0.11 m/s), ratio peak E/peak A velocities (CAD 1.0 +/- 0.27, normal 1.5 +/- 0.32), A area (CAD 0.052 +/- 0.015 m, normal 0.036 +/- 0.010 m), ratio E area/A area (CAD 1.7 +/- 0.53, normal 2.5 +/- 0.69), and all area fractions. In the CAD patients who had undergone coronary angioplasty, no differences were found in any Doppler index before and immediately after the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)