Optic nerve involvement in viral spread in herpes simplex virus type 1 retinitis.

Colchicine was used to block fast axonal transport of the optic nerve of the uninjected eye after uniocular anterior chamber inoculation of herpes simplex virus type 1 (HSV-1). The results of these experiments suggest that second-wave virus is transported to the retina of the uninjected contralateral eye through the optic nerve of the uninjected eye, since intravitreal treatment with colchicine reduced both the viral titer and prevalence of animals with histopathologic evidence of retinitis. The chemical block to viral entry provided by colchicine was both dose- and time-dependent, with administration of colchicine that was timed to interfere with the second viral wave being the most effective. Colchicine did not appear to be directly inhibitory to viral replication or toxic to the virus, and colchicine did not cause clinical or microscopic evidence of retinal inflammation. Intravitreal injection of colchicine did not alter the timing or recovery of the first wave of virus.

Short-term effects of levobunolol on ocular pulsatile flow.

In a randomized, double-masked, placebo-controlled study, we evaluated the effect of levobunolol 0.5%, a nonselective beta-blocker, on intraocular pressure, volume amplitude, and ocular pulsatile flow in healthy individuals and patients with glaucoma. Volume amplitude and ocular pulsatile flow were derived from measurements of pulse amplitude with a pneumatonometer. Two hours after instillation of levobunolol, intraocular pressure decreased from 26.0 +/- 5.1 mm Hg to 17.8 +/- 3.9 mm Hg (28.3%) (P less than .001) in glaucomatous eyes and 20.2 +/- 3.6 mm Hg to 14.5 +/- 4.2 mm Hg (29.6%) (P less than .001) in healthy eyes. Ocular pulsatile flow was increased after treatment with levobunolol from 482.1 +/- 133.3 microliter/minute to 548.5 +/- 180.3 microliter/minute (13.3%) (P less than .006) in glaucomatous eyes and 457.6 +/- 178.2 microliter/minute to 528 +/- 223.8 microliter/minute (12.3%) (P greater than .05) in healthy eyes. There was no significant change in intraocular pressure, volume amplitude, or ocular pulsatile flow in placebo-treated eyes. The implication of these data for glaucoma therapy is not clear. Although we used an instrument that supposedly measures total pulsatile flow, it may be that optic nerve blood flow is dependent on total, both pulsatile and nonpulsatile, flow. Further, even though retinal blood flow is a small component of total ocular blood flow, it may be equally or more important than choroidal flow because of the necessity to maintain the perfusion of the retinal ganglion cells.

Age-related changes in the human lens: a comparison of Scheimpflug photography and lens density index.

Two quantitative techniques, Scheimpflug photography and the lens density index (LDI), were used to measure lens density in 52 patients. In the Scheimpflug technique, a digitized slitlamp camera provides peak and average nuclear density based on a densitometric analysis of the lens nucleus. The LDI is a psychophysical measurement of the difference between retinal scotopic thresholds for two wave-lengths of light. Both the Scheimpflug technique and LDI revealed an age-related increase in lens density. Peak and average nuclear density were highly correlated with the LDI.

Reproducibility of optic nerve head topography measurements in eyes with undilated pupils.

A confocal scanning diode laser ophthalmoscope (Retina Tomograph, Heidelberg Engineering, GmbH, Heidelberg, F.R.G.) was used to examine the optic nerve head in both normal healthy (n = 10) and glaucomatous (n = 10) eyes. An image series was obtained from 32 transverse optical sections taken at consecutive height planes (50-80 mum each) over a 1.5-2.5-mm scan depth. Each image was then analyzed to create a topographic map containing 256 +/- 256 pixels (65,536 pixels) with afield of view of 10+/-. Images were obtained through undilated pupils. Reproducibility was 30.1 +/- 7.0 and 31.8 +/- 10.6 mum in normal and glaucomatous eyes, respectively. The instrument provides highly reproducible topographic data of the optic nerve head in patients with undilated pupils.

Anterior chamber angle configuration before and after iridotomy measured by scheimpflug video imaging.

Anterior chamber angles were measured before and after laser iridotomy in 12 patients with narrow angles using Scheimpflug video image analysis. The angle increased from a mean of 15.3 +/- 2.5 degrees (mean +/- SD) to 21.2 +/- 3.3 degrees following iridotomy. This difference was significant (p < 0.0005). There was no significant change in the depth of the axial anterior chamber. This instrument may be useful as an adjunct to clinical examination, particularly when an objective, quantitative grading of anterior chamber angle changes is required.

Reproducibility of quantitative anterior chamber angle measurements with scheimpflug video imaging.

A Scheimpflug video camera with digital image analysis was used to assess iridocorneal angles in 11 eyes with nonoccludable open angles and nine eyes with occludable narrow angles. Normal eyes had a mean angle width of 28.2 +/- 2.5 degrees and eyes with occludable narrow angles had a mean angle width of 17.5 +/- 3.2 degrees . Interobserver variability was 1.98 degrees and 1.94 degrees in open and narrow angles, respectively. Intraobserver variability was 1.81 degrees . This technique provides a method for longitudinal observation and quantitative assessment of the iridocorneal angle.

The effect of topical beta-adrenoceptor blocking agents on pulsatile ocular blood flow.

Thirty-three ocular hypertensive patients (21 with primary open angle glaucoma and 12 glaucoma suspects) were randomly assigned to receive either timolol, levobunolol or betaxolol in one eye. Pulsatile ocular blood flow (POBF) was measured before treatment (baseline) and 2 hours after drop administration. After 1 week of regular twice-daily dosage, POBF was measured again both immediately before and 2 hours after drop instillation. All measurements were made by an investigator masked to treatment. POBF increased by 11% (p = 0.09) at week 0 after levobunolol administration, and by 22% (p = 0.20) at week 1 before drop administration compared with baseline. It dropped by 23% and 25% (p = 0.04 and 0.06, respectively) before and after betaxolol administration at week 1. Although POBF was reduced in the timolol group, this change was not significant. These results can not be explained uniformly by changes in intraocular pressure or blood pressure. The relevance of these measurements to visual function in glaucoma is not known.