Miles A. Galin

Time analysis of corneal endothelial cell density after cataract extraction.

Serial endothelial photographs were taken preoperatively and postoperatively in 200 eyes; 111 eyes contained a Rayner iris clip lens, 54 eyes contained a Fyodorov Sputnik lens, and 35 eyes had no lens. Central endothelial cell density was changed in all instances, with counts in implanted eyes declining 25 to 30%, and in nonimplanted eyes 10 to 15%. In both instances, the decline essentially ceased at about three months. The cause of the greater decline in implanted eyes appeared to be mechanical and subsequent cell loss after the 90-day period was virtually equal for the two groups. Methods that may be used to alter the difference in cell density occurring with implantation are best analyzed by using the 90-day period data for comparison.

Endothelial Cell Loss from Intraocular Lens Insertion

ALTHOUGH intraocular implants for replacement of cataractous lenses were first used more than 25 years ago, they have begun to gain acceptance only recently in the United States, and still with considerable caution.1,2 One of the chief reasons for concern has been the high incidence of early and, in particular, late development of bullous keratopathy due to corneal endothelial decompensation arising in the early series of eyes with anterior chamber and angle-supported lenses. Barraquer inserted nearly 500 such lenses in the late 1950s but had removed half of them by 1970 many because of corneal edema, a complication which was nqt recognized until several

Levobunolol: A Beta-adrenoceptor Antagonist Effective in the Long-term Treatment of Glaucoma

We compared the ocular-hypotensive efficacy and systemic and ocular safety of an ophthalmic solution of levobunolol (0.5% and 1%) twice daily, with timolol (0.5%) twice daily in a long-term double-masked study of 391 patients with open-angle glaucoma or ocular hypertension. Patients received the test medication in both eyes for up to two years. Over the two-year period, both concentrations of levobunolol reduced mean IOP by 27% (range, -6 to -8 mmHg). This ocular-hypotensive effect was sustained throughout the study and was similar to that produced by timolol. Slight decreases in mean heart rate and blood pressure were observed. No unexpected adverse ocular or systemic reactions were reported. The results of these studies indicate that levobunolol is an effective therapy for the long-term treatment of glaucoma.

Longterm timolol therapy

Of 145 patients registered for an investigation of timolol, 27 patients were dropped for unrelated reasons. Among the remaining 118 patients (212 eyes), a significant reduction in intraocular pressure resulted from twice-a-day topical instillation of 0.25 or 0.5% timolol to ocular hypertensives, primary open-angle glaucoma or aphakic glaucoma patients. Outflow facility improved only slightly, but remained improved throughout the course of this study. A significant reduction in aqueous secretion, however, was the predominant cause of intraocular pressure reduction. Timolol alone controlled intraocular pressure in 87% of ocular hypertensives, in 68% of patients with chronic open-angle glaucoma and in 68% of patients with angle-unobstructed aphakic glaucomas. The addition of epinephrine brought the intraocular pressure to less than 22 mm Hg in 85% of the total group of patients.

Levobunolol vs timolol for open-angle glaucoma and ocular hypertension.

A group of 162 patients with chronic open-angle glaucoma or ocular hypertension were treated twice daily for up to 15 months with one of the following topical ophthalmic solutions: 0.5% levobunolol, 1% levobunolol, or 0.5% timolol. Overall mean reductions in intraocular pressure were 8 mm Hg for patients receiving 0.5% levobunolol or timolol and 8.2 mm Hg for patients receiving 1% levobunolol. There were no significant differences between levobunolol and timolol in mean reductions in intraocular pressure, percent of patients with adequately controlled intraocular pressure, or life-table estimates of the probability of successful treatment.

The Effects of Timolol on Cataract Extraction and Intraocular Pressure

We studied the effect of timolol on post-operative intraocular pressures (IOPs) in a control and experimental group of 30 eyes, each in patients who had uncomplicated intracapsular cataract extractions, most with iris clip lenses. Closure of the eye in each case was with three 6-0 silk sutures preplaced in a morticed incision. Six control eyes had IOP increases of 6 mm Hg or more within 24 hours of surgery. One patient treated with timolol had an IOP increase of 6 mm Hg or more. The differences in IOP between the control and experimental groups were statistically significant at the .01 level. The pressure lowering ability of timolol appears to be prophylactic as well as therapeutic. It is well suited for pseudophakic eyes as pressure reduction is not associated with pupillary alterations.

Detection, Removal, and Effect of Unpolymerized Methylmethacrylate in Intraocular Lenses

Gas-liquid chromatography, infrared spectroscopy, or Raman spectroscopy were used to determine the level of monomer in intraocular lenses and in the preforms used in each step of the manufacturing process. Heating, lathing, molding, and grinding caused an increase in monomer content, presumably the result of depolymerization. The tendency of methylmethacrylate to volatilize, repolymerize, or dissolve precludes high monomer contents from persisting in intraocular lenses. Vacuum ovens or water baths significantly reduced the monomer content to levels of 0.5% or less. Lenses with a monomer content higher than that found in currently available commercial lenses had no effect on rabbit kidney cell cultures. Lens fragments with a similarly elevated monomer content were indistinguishable from lenses with a low monomer content in rabbit eyes. According to these data, monomer does not appear to be a toxic agent in currently available intraocular lenses.

Tissue Culture Methods for Testing the Toxicity of Ocular Plastic Materials

A screening method using tissue culture techniques determined inertness of ocular alloplastics. Secondary rabbit kidney cells revealed the presence of toxic constituents by absence of growth or cytopathic changes, or both. The optical portions of the lenses studied were nontoxic, whereas the polyamide loops of one lens were toxic. A keratoprosthesis that had been in situ in a patient for two years was highly toxic in culture. A neutralized agar overlay technique was not sufficiently sensitive to screen anterior chamber implants. The tissue culture technique, in combination with chemical, optical, and animal experimentation, may be helpful in determining which implant systems are most suitable for in vivo use.

THE OCULAR PULSE — TECHNICAL FEATURES

Ocular techniques to study carotid occlusive disease include ophthalmodynamometry, carotid compression-tonography, and ocular pulse measurements. Studies using this latter method have been concerned primarily with the amplitude of the recorded pulse, and it has been noted that a reduction in amplitude of the ocular pulse occurs on the side of carotid occlusive disease (Castren et a2. 1964, B y n k e 1966, 1968a, 1968b, and 1969, B y n k e and Krakau 1964, Lester 1966, Bron et al. 1967, Galin et al. 1967b). Changes in the contour of the ocular pulse recordings have not received much attention although contour analysis has been of great importance in peripheral vascular disease (Winsor 1959). Ocular pulses recorded from the surface of the eye with a suction cup are similar in all respects to pulses recorded by direct cannulation and reflect the pressure changes occurring in the eye during the cardiac cycle (Lawrence et al. 1966). This report concerns itself with a consideration of the suction technique used to record ocular pulses and the effects of various physical factors upon the pulse amplitude, peak characteristics and notching.

Experimental Cataract Surgery

The use of intraocular lenses in cataract surgery leads to a greater corneal complication rate than surgical treatment without such devices. 1–3 It has been assumed that the predominant reason for this is surgical trauma at the time of lens insertion. 4 A laboratory study to verify and analyze this difference has been carried out, the cat being used as an experimental model. This first report evaluates the effect of the usual steps of cataract extraction on the density of corneal endothelial cells.