Eales' disease with central nervous system infarction

Eales' disease is a noninflammatory occlusive disorder of the retinal vasculature that causes recurrent hemorrhages into the retina and vitreous and ischemic changes in the eye. Extraocular manifestations of Eales' disease are rare and limited to the central nervous system. We report the case of a patient with Eales' disease and ischemic stroke, and we review the neurologic manifestations of this primarily ophthalmologic vasculopathy.

Tobramycin liposomes. Single subconjunctival therapy of pseudomonal keratitis

The authors compared 24 doses of hourly topical fortified tobramycin (Group A) therapy with a single subconjunctival administration of multivesicular megaliposome-encapsulated tobramycin (Group B) and free subconjunctival tobramycin (Group C) in treating a rabbit model of keratitis caused by Pseudomonas aeruginosa. One cornea each of 50 rabbits was infected with P. aeruginosa for 24 hr. The animals then were divided randomly into five groups of ten each. Groups A, B, and C were treated as described. Group D received liposomes without tobramycin and Group E, hourly balanced salt solution. Significantly fewer Pseudomonas colonies were present in the corneas of all three drug-treated groups (A, B, and C) compared with the two control groups (D and E) at 24 hr (P less than 0.005). Significantly fewer Pseudomonas colonies were present in Groups A and B compared with Group C (P less than 0.02). No significant difference was noted between Groups A and B (P = 0.30). Tobramycin encapsulated in megaliposomes may be useful in treatment of pseudomonal keratitis.

Hemorrhagic choroidal detachment with anterior vitreoretinal adhesions

We present three cases of large intraoperative or postoperative hemorrhagic choroidal detachment with subsequent adherence of the retina to anterior segment structures. Surgical management involved bimanual vitrectomy through anterior sclerotomy sites and dissection within the anterior segment. Successful retinal reattachment was achieved in two of these cases (18-months' follow up). In the third case, the retina remained attached for 4 months but then redetached.

Accuracy of topographic measurements in a model eye with the laser tomographic scanner

The authors evaluated the accuracy of topographic measurements with the laser tomographic scanner using a model eye. Diameter, depth, and shape at different axial lengths of four sample holes that simulated optic nerve heads in phakic and aphakic conditions were determined by confocal imaging. The computer-generated cross-section profiles of the simulated optic nerve heads corresponded well with the actual contours as photographed by scanning electron microscopy. The average relative error in diameter was 2.0% (range: 0.3-2.9%) for the phakic model eye and 3.6% (range: 0.6-8.2%) for the aphakic model eye. The average relative error in depth was 11.7% (range: 1.2-20.1%) for the phakic model eye and 10.1% (range: 1.7-22.6%) for the aphakic model.

Liposome suppression of proliferative vitreoretinopathy. Rabbit model using antimetabolite encapsulated liposomes

The effects of the antimetabolites, cytarabine (Ara-C) and 5-fluorouridine 5'-monophosphate (FUMP), encapsulated in multivesicular liposomes on formation of vitreous fibroproliferative membranes in New Zealand white (NZW) rabbits were studied. In pharmacokinetic studies, the drug half-life in the vitreous cavity was 124 hr after intravitreal administration of 1.0 mg of FUMP in liposomes. By contrast, the drug half-life after a single injection in nonliposome-treated controls was only 4.5 hr. In a heterologous dermal fibroblast model of proliferative vitreoretinopathy (PVR), there was a 92% decrease in frequency of tractional retinal detachments in rabbits receiving a single intravitreal injection of liposome-encapsulated 0.1 mg of FUMP compared with controls receiving liposomes without drug. A dose of 1 mg of Ara-C in liposome-treated rabbits was associated with only a 46% reduction in tractional detachment compared with controls. Multivesicular liposome-encapsulated FUMP may be useful for inhibiting formation of fibroproliferative membranes in the vitreous after vitreoretinal surgery.

Isolating the effects of primary open-angle glaucoma on the contrast sensitivity function

We evaluated spatial contrast sensitivity functions in age-matched and lens density-matched healthy eyes, eyes with primary open-angle glaucoma, and eyes with ocular hypertension. We also controlled for refraction, visual acuity, pupil size, and previous ocular history. We found an overall reduction in contrast sensitivity for the glaucomatous eyes with a significant difference at 12 cycles per degree (P less than .012). Eyes with ocular hypertension were not significantly different from normal eyes. Significant differences were noted at several spatial frequencies with less careful controls for age and lens effects. We concluded that spatial contrast sensitivity may be a useful adjunctive diagnostic test for glaucoma, but interpreting the results without other clinical data may lead to errors in diagnosis.

Reducing corneal toxicity of 5-fluorouracil in the early postoperative period following glaucoma filtering surgery

To gain a better understanding of the relationship between postoperative 5-fluorouracil administration and corneal complications associated with its use, we analysed 43 consecutive filtering procedures in which it had been employed. Nine of the 43 eyes had corneal complications during that period. At the end of the three-month period, these corneal complications had all resolved. There was no correlation between postoperative intraocular pressure lowering and incidence of corneal complications. A low dose of 5-fluorouracil, and early recognition and treatment of corneal toxicity associated with its use may reduce corneal complications while maintaining filtration in eyes with poor surgical prognosis.

Age-related changes in the human lens. Clinical assessment of age-related changes in the human lens

We compared two methods for assessing changes in the human lens associated with age. The first is a subjective method for quantifying light absorption by the lens. It is useful for determining the functional effect of age-related increases in lens density, especially for short-wavelength light. The second method objectively and rapidly measures the increase in scattered light with increasing lens density. These two methods accurately measured age-related changes and were highly correlated with each other (r = 0.72, P less than 0.001). Both methods were evaluated in a population of normal eyes, eyes with ocular hypertension, and eyes with primary open angle glaucoma. We found ni significant differences among these groups with either method.

Lysosomal enzyme activity in human aqueous humor

Activity of the lysosomal enzymes N-acetyl-beta-D-hexosaminidase, alpha-D-mannosidase, beta-D-glucuronidase, and beta-D-galactosidase was detected in aqueous humor from eyes undergoing intraocular surgery. There was no correlation between lysosomal enzyme activity and age. Lysosomal enzyme activity in human released by ocular tissues surrounding the anterior chamber including the cornea, trabecular meshwork, ciliary body, iris, and lens. Their release into aqueous humor may have a role in regulating aqueous outflow in normal and glaucomatous eyes.

New developments in the drug treatment of glaucoma

This article reviews standard treatment modalities for patients with glaucoma and describes 3 classes of drugs which are undergoing development: apraclonidine (aplonidine, ALO 2145), an alpha 2-adrenergic agonist which has been released for clinical use; topical carbonic anhydrase inhibitors, a modification of the systemic carbonic anhydrase inhibitors currently in use; and prostaglandins (PGs), a new class of drugs with topical ocular hypotensive activity. Standard treatment modalities include parasympathomimetic agents such as pilocarpine, carbachol, and phospholine iodide, which lower intraocular pressure (IOP) by increasing aqueous outflow through the trabecular meshwork. A newer form of pilocarpine as a gel produces a longer action. Adrenergic agonist medications, such as epinephrine (adrenaline) and its prodrug dipivefrine (dipivalyl epinephrine), function by increasing uveoscleral outflow and trabecular outflow facility. A decrease in aqueous formation by the ciliary processes is thought to be the mechanism of action of beta-adrenoceptor antagonists, but the physiological basis for this action has not been clearly demonstrated. A newer beta-blocker, betaxolol, has relatively selective beta 1-blocking activity. Carbonic anhydrase inhibitors are nonbacteriostatic sulphonamide derivatives which decrease aqueous formation by the ciliary body. Almost 50% of patients taking these medications are unable to tolerate them because of their adverse effects, and there is thus much interest in the development of a topical carbonic anhydrase inhibitor with the potential for fewer adverse effects. MK 507 is the most recent and most potent compound in the series of topically active carbonic anhydrase inhibitors. Apraclonidine hydrochloride is a derivative of clonidine hydrochloride, an alpha 2-adrenergic agonist. Clonidine has previously been shown to lower IOP significantly, but has the potential to produce marked lowering of both systolic and diastolic blood pressures. Its major ocular effect appears to be a decrease in aqueous production. The structural modification to apraclonidine decreases corneal absorption and the drug's ability to cross the blood-brain barrier, minimising the risk of centrally mediated cardiovascular side effects. Apraclonidine may also influence secondary avenues of aqueous outflow, such as uveoscleral outflow, and may also affect conjunctival and episcleral vascular flow. It produces a mean decrease in IOP of 25% for as long as 12 hours. Adverse effects include blanching of the conjunctiva, minimal mydriasis and eyelid retraction. This drug has been approved in the US for use in prevention of elevated IOP after argon laser trabeculoplasty and iridotomy, and has potential uses in preventing an IOP rise after YAG laser posterior capsulotomy and cataract surgery in patients already on other antiglaucomatous medications.(ABSTRACT TRUNCATED AT 400 WORDS)

MK-507 versus sezolamide. Comparative efficacy of two topically active carbonic anhydrase inhibitors

Topical carbonic anhydrase inhibitors MK-507 and sezolamide hydrochloride (previously known as MK-417) were compared in a double-masked, randomized, placebo-controlled study in 82 patients with bilateral primary open-angle glaucoma or ocular hypertension. MK-507 was given every 8 or 12 hours, sezolamide every 8 hours, or placebo every 8 or 12 hours for 4 days. Both drugs lowered intraocular pressure (IOP) substantially. MK-507 was somewhat more active than sezolamide, with a peak mean IOP reduction of 26.2% for MK-507 versus 22.5% for sezolamide, although the difference between the treatments was not statistically significant. These drugs may have potential in the treatment of glaucoma.

Reproducibility of topographic measurements of the normal and glaucomatous optic nerve head with the laser tomographic scanner

We acquired five independent topographic images of the optic nerve head of eight normal eyes and eight eyes with primary open-angle glaucoma with a laser tomographic scanner. Each image had a field of view of 15 x 15 degrees with a resolution of 256 x 256 pixels. The pixel size was approximately 15 x 15 microns. The value of a pixel of a topographic image represented the height at this position. The mean height and the standard deviation over the five topographic images were calculated for each of the 65,536 pixel positions. The standard deviation of a single height measurement in normal eyes was 38.7 microns (range, 23.4 to 62.2 microns) for areas in the peripapillary retina and 42.6 microns (range, 24.4 to 53.7 microns) for measurements within the optic nerve head area. In glaucomatous eyes, the standard deviation was 41.2 microns (range, 23.2 to 59.6 microns) in the peripapillary retina and 49.4 microns (range, 28.1 to 72.8 microns) within the optic nerve head. There was no significant difference between the standard deviation of a single height measurement in normal and glaucomatous eyes (P = .34 within the optic nerve head area; P = .57 on peripapillary retina). No correlation was found between standard deviation of the measurements and pupil size or age of the subject.

Cytokeratin patterns in corneal, limbal, and conjunctival epithelium. An immunofluorescence study with PKK-1, 8.12, 8.60, and 4.62 anticytokeratin antibodies

The authors examined immunofluorescently the specific cytokeratin staining patterns of corneal, limbal, and conjunctival epithelium with PKK-1, 8.12, 4.62, and 8.60 monoclonal anticytokeratin antibodies. Observations were made on unfixed frozen postmortem human tissue. The PKK-1 antibody stain was observed in all layers of corneal epithelium but only in suprabasal layers of limbal and conjunctival epithelium. By contrast, the 8.12 antibody stain was observed only in the superficial layer of corneal epithelium but through all layers of limbal and conjunctival epithelium. The 4.60 antibody stain was seen in focal areas of corneal and limbal epithelium and through all layers of conjunctival epithelium. The 8.60 antibody stain was not present in the three epithelia. These immunofluorescence studies showed unique cytokeratin patterns among layers in corneal, limbal, and conjunctival epithelium.

Glaucoma secondary to epithelial downgrowth and 5-fluorouracil

Since epithelial downgrowth involves an actively proliferating intraocular tissue, it is possible that the antimetabolite 5-fluorouracil may inhibit it. We report a case of secondary glaucoma caused by epithelial downgrowth in which filtration surgery was performed with adjunctive use of subconjunctival 5-fluorouracil. On cessation of the injections, the retrocorneal membrane grew rapidly to involve the entire posterior cornea. The eye eventually became blind and painful and was enucleated. The use of 5-fluorouracil given in the usual manner appears to have been a failure.

Effects of ultraviolet irradiation on prostaglandin-E2 production by cultured corneal stromal cells

We examined the effects of ultraviolet (UV) irradiation on the release of prostaglandin E2 (PGE2) by rabbit corneal stromal cells in culture. Considerable amounts of PGE2 were present in the media of control corneal cultures following 1, 2, 4, 8 and 24 hr of incubation. Irradiation with UV-A (320-400 nm) for 30 min resulted in more than a 50% increase in PGE2 release. Dexamethasone inhibited PGE2 release by corneal stromal cells. It was, however, ineffective in protecting the cells from the UV-induced release of PGE2.

Color perimetry for assessment of primary open-angle glaucoma

The authors report the development of a color perimetry procedure which compares sensitivity of the short-wavelength color-vision mechanism in the peripheral visual field for normal eyes, eyes with ocular hypertension, and eyes with primary open-angle glaucoma. To isolate the short-wavelength cone mechanism, they modified an automatic projection perimeter to blue-on-yellow color perimetry and used a monochromatic 440-nm stimulus and a broad-band bright yellow background. The three groups of subjects were matched for age and lens density. Refraction, pupil size, acuity, and medication were controlled. Under these conditions, most glaucomatous eyes showed reduced sensitivities more than two standard deviations below normal. Normal control eyes were significantly different from eyes with ocular hypertension only in the superior nasal field (P less than 0.05), but normal eyes differed from eyes with primary open-angle glaucoma in all areas of the field (P less than 0.01).

In situ localization of cytoskeletal elements in the human trabecular meshwork and cornea

The authors compared cytoskeletal elements of the in situ human trabecular-meshwork cell with in situ human corneal cells using indirect immunofluorescence staining for tubulin and intermediate filaments (vimentin, cytokeratin, and desmin) and NBD-phallacidin staining for f-actin using both fixed frozen and unfixed frozen sections from postmortem eyes. Both f-actin and tubulin were found throughout the cell body of trabecular-meshwork cells, keratocytes, corneal endothelium, and corneal epithelium. The f-actin staining pattern was concentrated at the cell periphery of these four cell types. Vimentin stain was intensely localized in focal areas of the trabecular-meshwork cell, keratocytes, and throughout the corneal endothelium. A general anticytokeratin antibody was intensely localized in corneal epithelium and endothelium. However, PKK-1 anticytokeratin antibody was seen only in superficial layers of corneal epithelium and not in corneal endothelium. The 4.62 anticytokeratin antibody was not observed in either corneal epithelium or endothelium. None of these three cytokeratin antibodies were seen in trabecular-meshwork cells or keratocytes. Desmin stain was not noted in any of these cell types. In general, cytoskeletal staining of unfixed frozen sections showed a similar staining pattern for f-actin and tubulin but a more uniform and intense staining pattern for vimentin and cytokeratin compared with fixed frozen material. The authors conclude that these cytoskeletal stains can differentiate human trabecular-meshwork cells from cells of the cornea in situ.

A double-masked three-month comparison between 0.25% betaxolol suspension and 0.5% betaxolol ophthalmic solution

In 352 patients with primary open-angle glaucoma or ocular hypertension, a multicenter double-masked, parallel-group clinical study compared the effects on intraocular pressure and ocular comfort of 0.5% betaxolol ophthalmic solution, a cardioselective beta-adrenergic blocking agent, with 0.25% betaxolol suspension. With twice-daily dosages, baseline intraocular pressure was significantly reduced (P = .0005), with no significant difference between the two groups, at Week 2 and at Months 1, 2, and 3. Further, the prevalence of ocular discomfort upon topical instillation was significantly lower for 0.25% betaxolol suspension than for 0.5% betaxolol solution (P = .0005).

Characterization of lysosomal enzymes from cultured cynomolgus monkey trabecular meshwork cells

The current study characterizes selected properties of lysosomal enzymes associated with cynomolgus monkey trabecular meshwork (MTM) cells. These proteins may participate in the turnover of macromolecules involved in regulating the aqueous outflow. Intracellular levels of lysosomal enzymes in MTM cells were similar to those found in cultured human fibroblasts. The presence of ammonium chloride increased the secretion rate of certain lysosomal enzymes from 47 to 122% of normal. Column chromatography of the secreted enzymes on the galactose-specific lectin Ricinus communis I demonstrated an increase in the number of accessible galactose residues on lysosomal enzymes secreted in the presence of ammonium chloride. The presence of mannose-6-phosphate receptors on the trabecular meshwork cells was demonstrated by the specific uptake of purified 125I-beta-D-glucosidase. This uptake represented 20% of that observed with cultured human fibroblasts and was inhibited only 50% by the presence of mannose-6-phosphate.

Histopathologic validation of Fourier-ellipsometry measurements of retinal nerve fiber layer thickness

We describe a new technique for the measurement of retinal nerve fiber layer thickness and compare its results with histopathologic measurements in the same eyes. For these studies, two fixed monkey eyes were incised and placed on a pedestal in a plastic viewing dish. The eyes were perfused to maintain a pressure between 10 and 20 mm Hg. An ellipsometer, an optical device used to measure the change in polarization of light (retardation), was implemented in a laser tomographic scanner to obtain polarization data from the two monkey retinas. For the 15 measured locations, retardation ranged between a mean (+/- SD) of 0.9 degrees +/- 1.8 degrees and 23.7 degrees +/- 0.3 degrees. Subsequently, retinal nerve fiber layer thickness was measured at the imaged points in epoxy resin-embedded sections by an observer masked to the ellipsometry data. These values ranged between 20.4 microns and 213.9 microns. There was an excellent correlation (R = .83) between retardation and the histopathologic measurement of retinal nerve fiber layer thickness. Quantitating retinal nerve fiber layer thickness may enhance discrimination between glaucomatous and normal eyes earlier than is currently available by anatomic and functional approaches.

Anterior ischaemic optic neuropathy and intraocular pressure

Anterior ischaemic optic neuropathy is a stroke syndrome of the distal optic nerve, characterised by disc oedema and optic nerve dysfunction--loss of central vision, loss of colour vision, a relative afferent pupillary defect, and nerve fibre layer field loss. We prospectively evaluated the changes of intraocular pressure throughout the day in 16 patients with non-arteritic anterior ischaemic optic neuropathy and 15 normal control subjects of similar age and race. The peak intraocular pressure exceeded 21 mm Hg in five of the ischaemic optic neuropathy patients but none of the controls. The mean peak intraocular pressure was 19.9 mm Hg for the ischaemic optic neuropathy group versus 17.6 mm Hg for controls (p = 0.034). The range of intraocular pressure was also greater for the ischaemic optic neuropathy group (p = 0.030). Eight of 16 ischaemic optic neuropathy patients had a range of intraocular pressure of 6 mm Hg or more, compared with three of 15 control subjects. The intraocular pressure exceeded 21 mm Hg during a subsequent visit in two additional patients in whom the hourly determined intraocular pressure peaked at less than 21 mm Hg. Thus, seven of 16 of our ischaemic optic neuropathy group had an intraocular pressure exceeding 21 mm Hg during the study period. Raised intraocular pressure may be a predisposing factor in some patients who develop anterior ischaemic optic neuropathy.

Ammonia as a potential mediator of adult human periodontal infection: inhibition of neutrophil function

Neutrophils (polymorphonuclear leucocytes) are the principal cell of the host defence system. Consequently, if periodontal pathogen-derived substances in the gingival crevice significantly inhibit their function, they could shift the bacterial-host balance in favour of the bacteria. The hypothesis that ammonia can inhibit neutrophil function was tested. Ammonia was specifically selected because periodontal pathogens produce substantial amounts of ammonia. The findings indicated that ammonia can inhibit neutrophil phagocytosis, degranulation and oxygen metabolism. Ammonia decreased the total number of phagocytosing polymorphonuclear neutrophils (66% of control) and also decreased degranulation (61% of control). Ammonia decreased oxygen metabolism of both resting and stimulated neutrophils (33 and 42% of control, respectively). These observations support the hypothesis that ammonia can inhibit the function of polymorphonuclear leukocytes. They suggest that the presence of ammonia in the gingival crevice may increase the risk of development of periodontal disease.

The effect of increased intraocular pressure on visual acuity and corneal curvature after radial keratotomy

To detect the effect of increased intraocular pressure on visual acuity and corneal curvature after radial keratotomy, we measured these variables in the sitting and inverted positions in 18 patients who underwent radial keratotomy (Group 1) and compared their results with those from the unoperated on eyes of seven patients (Group 2). We also compared the results before and after inversion within each group. Intraocular pressure increased to approximately two times normal in each group. Significant improvement in visual acuity and reduction in central keratometry were noted only in Group 1. By multiple regression analysis, visual improvement correlated with the number of incisions but not the time since surgery. Our study provides evidence that increased intraocular pressure may account for transient changes in vision and corneal curvature after radial keratotomy.

The extracellular matrix of the human optic nerve

The nerve fibers of the optic nerve are enclosed and segmented by extracellular matrix. With immunostains, we localized collagen types I through VI, laminin, and fibronectin in frozen sections of the extracellular matrix of the prelaminar, laminar, and retrolaminar human optic nerve. The internal limiting lamina of the optic nerve has an extracellular composition similar to the thicker adjacent retinal internal limiting lamina. We confirmed that the lamina cribrosa contains type IV collagen and laminin, whereas the sclera does not. The septa of the retrolaminar optic nerve appear as vascular inward extensions of the pia mater. The glial tube that lines the optic nerve extends forward from the retrolaminar optic nerve through the lamina cribrosa to end anteriorly at the retinal pigment epithelium. It does not separate the optic nerve from the adjacent sensory retina.

Optic neuropathy associated with cryptococcal arachnoiditis in AIDS patients

We studied two cases of bilateral visual loss secondary to an optic neuropathy in patients with cryptococcal meningitis. In both cases a history of visual loss after the onset of an episode of cryptococcal meningitis was elicited. Visual fields were consistent with optic nerve disease. The patients' visual loss appeared to be the result of perineuritic adhesive arachnoiditis. Although no surgical interventions were carried out in our patients, medical or surgical intervention may be useful to prevent or relieve constrictive arachnoiditis and preserve vision in selected patients.

Prostaglandin production by cultured cynomolgus monkey trabecular meshwork cells

Monkey trabecular meshwork (MTM) cells synthesize a variety of prostaglandins, including large amounts of prostaglandin E2 (PGE2) and smaller amounts of 6-keto-PGF1 alpha and PGF2 alpha. The predominance of PGE2 production by the MTM cells is similar to that observed in human trabecular meshwork cells. In contrast, the relative amounts of 6-keto-PGF1 alpha and PGF2 alpha were reversed compared with the human cells. The MTM cells produced increased amounts of PGE2 in response to treatment with bradykinin, platelet activating factor, and A-23187. Dexamethasone caused a dose-dependent inhibition of PGE2 production with 50% inhibition by 10(-8) M, although this response was variable.

A practical method for obtaining an index of lens density with an automated perimeter

Uncontrolled variables often limit meaningful assessment of visual sensitivity. Previously, we developed a procedure and apparatus for in vivo assessment of light absorption by the human lens. In the current study, we modified a widely used automated perimeter to include our procedure for obtaining an index of lens density. Nineteen individuals were tested on both the original apparatus and the modified perimeter. Results were comparable with a correlation of r = 0.92 (P less than 0.01). We conclude that employing the procedure on an automated perimeter is a practical method for obtaining an accurate lens density index.

Active optical depth resolution improvement of the laser tomographic scanner

Laser scanning tomography can be used to assess retinal nerve fiber layer thickness and optic disc topography of the human eye. A pinhole is located at a plane conjugate to the focal plane of the scanning laser beam. This so-called confocal configuration assures that only the light originating from the illuminated focal plane on the retina passes through the pinhole and is detected by the photomultiplier. Consequently, images with high spatial resolution in all directions are obtained. An active optical system (active mirror) further improves the lateral/depth resolution of the laser tomographic scanner. By partially compensating for the optical aberrations introduced by the cornea and lens, the active optical system allows the illuminating beam to be enlarged to 6 mm, thus improving depth resolution twofold.

Quantitative assessment of the optic nerve head with the laser tomographic scanner

We describe the use of a laser tomographic scanner to objectively measure optic nerve head topography. A laser beam is focused on the optic disc using confocal imaging. Reflected light is detected only if it originates from a small region around the focal place of the special optics. Optic disc parameters are calculated from the measured values of confocal reflected light. In five glaucomatous eyes, maximum cup depth was between 0.33 mm and 0.58 mm. Cup volume was between 0.10 mm3 and 0.65 mm3; it correlated well with ophthalmoscopy. Compared with conventional imaging systems, the laser tomographic scanner has certain advantages: 1) images can be obtained with miotic pupils; 2) clarity of media is not important; 3) low light intensity is employed; and 4) a real time image is obtained.

Isolating the color vision loss in primary open-angle glaucoma

We evaluated the results of Farnsworth-Munsell 100-Hue tests in age- and lens density-matched eyes of normal subjects, glaucoma suspects, and patients with primary open-angle glaucoma. With these controls in place, no significant correlation between the test results and age or between the test results and lens density was found. However, a significant difference in the total error scores on the 100-Hue test remained. This difference could not be explained by pupil size or medications taken. We concluded that color vision loss in glaucoma is in part attributable to the disease process and cannot be explained solely on the basis of changes in age and lens density.

Arachidonic acid metabolism in human trabecular meshwork cells

Prostaglandins and other eicosanoids in the trabecular meshwork may play important physiological and pharmacological roles in the aqueous outflow pathway. In the present studies, we employed [14C]-arachidonic acid to explore potentially important pathways for the production of eicosanoids in cultured human trabecular meshwork cells (HTM). In these cells, we demonstrated that prostaglandin E2 (PGE2) and PGF2 alpha are major cyclooxygenase products, with some 6-keto-PGF1 alpha also detected. The amount of radiolabelled PGE2 formed was substantially higher than the PGF2 alpha formed in the early time periods. The amount of PGF2 alpha in the culture media increased at a time when the amount of PGE2 was declining, suggesting a possible metabolic conversion between the prostaglandins. HTM produced a range of products of the lipoxygenase pathway. Products co-eluting with 5, 12, and 15-hydroxyeicosatetraenoic acids (HETEs) were detected, with 12 and 15-HETEs predominating. A large amount of radiolabelled product was detected also in peaks co-eluting with leukotriene B4 (LTB4) and an LTB4 degradation product. Biosynthesis of lipoxygenase products was markedly inhibited by BW 755c and partially inhibited by dexamethasone. These data emphasize that HTM cells are capable of converting arachidonic acid into a wider variety of biologically active products than previously recognized.

Intraocular pressure response after pneumatic retinopexy

We measured intraocular pressure over a five-day period in ten consecutive patients undergoing pneumatic retinopexy to determine the effect of an expanding gas bubble. During treatment, all eyes received 0.3 ml perfluoropropane gas. All eyes had an immediate rise in intraocular pressure, which in four eyes was associated with absence of central retinal artery perfusion for three minutes. Once intraocular pressure fell toward baseline (30 to 60 minutes after gas injection), we did not find a high intraocular pressure during the subsequent five-day period. We conclude that intraocular pressure-reducing medication is not routinely indicated in these eyes.

Long-term betaxolol therapy in glaucoma patients with pulmonary disease

We evaluated the use of topically administered betaxolol 0.5% in 101 glaucoma patients (47 men and 54 women) who had chronic obstructive pulmonary disease, asthma, or timolol-induced bronchoconstriction. Betaxolol 0.5% was administered twice daily and patients were reexamined at three-month intervals for up to two years. In addition to measurement of intraocular pressure, pulmonary function tests were obtained before therapy (baseline), two or three weeks after initiating betaxolol therapy, and at yearly intervals. Before treatment with betaxolol, the mean ratio of forced expiratory volumes in one second (FEV1) to forced vital capacity (FVC) was 66.3% (n = 101). After two weeks of betaxolol treatment, mean FEV1/FVC ratio was 66.2% (n = 101). After one year of betaxolol therapy, mean FEV1/FVC ratio was 60.1% (n = 24), and after two years it was 54.4% (n = 5). Nine patients developed symptoms that may have been associated with betaxolol treatment and were withdrawn from the study. Five of these patients developed symptomatic pulmonary obstruction between one and 554 days after initiating betaxolol treatment. Topically administered betaxolol was well tolerated by most glaucoma patients with concomitant pulmonary disease.

The aging lens: in vivo assessment of light absorption in 84 human eyes

We have developed an apparatus and psychophysical paradigm for the reliable and practical measurement of light absorption by the human crystalline lens. Using this procedure we can partition a loss of sensitivity with aging into that attributable to changes in the lens and that due to other factors. The procedure eliminates effects of inaccurate refractive correction and misalignment, and reduces the effects of pupil size. Results on 84 eyes showed a gradual decrease in sensitivity with age, especially for short wavelengths. We noted considerable individual variability, which points up the value of using a procedure that assesses sensitivity loss due to lens absorption for each tested individual.

Microtubule-granule relationships in motile human polymorphonuclear leukocytes

We examined the relationship of microtubules to the granule organization in stimulated human polymorphonuclear leukocytes (PMNs). Electron microscopic (EM) observations of critical-point-dried PMNs revealed that only a portion of the granules appeared in close association to microtubules. These closely associated granules appeared to be attached to the microtubule via smaller-diameter filaments. The remaining granules appeared either attached to microtubules at a further distance, via smaller-diameter filaments such as actin, or unassociated with microtubules. EM observations of PMNs treated with either the microtubule promoter drug taxol or the microtubule depolymerization drugs nocodozole and colchicine revealed a redistribution of granules towards the nucleus. Granule clustering at the periphery of the cell was also noted with nocodozole and colchicine. With cytochalasin B, a uniform distribution of granules was noted. However, granule clustering was noted when PMNs were coincubated with cytochalasin B and colchicine. These results indicate that microtubules may have both a direct and indirect role (through other cytoskeletal elements) in the organization of PMN granules.

Sustained release of the antimetabolite 5-fluorouridine-5'-monophosphate by multivesicular liposomes

We have developed a novel liposome for sustained drug delivery to the eye of the antimetabolite 5-fluorouridine-5'-monophosphate (FUMP), a potent metabolite of 5-fluorouracil. The in vitro half-life of FUMP incorporated within these liposomes was 585 hours. Following subconjunctival administration of 1 mg of FUMP to 13 New Zealand white rabbits, the tissue drug level at the injection site was significantly greater in the group treated with liposomes than it was in the group not treated with liposomes (p = .02). These liposomes offer the potential for sustained release of FUMP in the eye. By controlling the rate of drug release, it may be possible to reduce the need for frequent drug administration and its associated ocular toxicity as well as to improve treatment efficacy.

Prostaglandin E2 and protein release following Nd:YAG laser application to the anterior capsule of rabbit lens

We compared the effects of Nd:YAG laser anterior capsulotomy and photophacofragmentation on the release of prostaglandin E2 (PGE2) and protein in the New Zealand rabbit aqueous humor. Following anterior capsulotomy, the concentration of PGE2 was significantly more elevated (P less than .025) than it was in the contralateral untreated eyes at intervals from one-half hour up to four hours, and rapidly decreased in 24 hours. The concentration of protein showed a relatively gradual increase which became significant (P less than .05) after two hours, and remained elevated 24 hours after anterior capsulotomy. In contrast, photodisruption into the lens without damaging the anterior capsule showed little effect on the release of PGE2 and protein in the aqueous humor.

Quantitative assessment of cynomolgus monkey trabecular cell phagocytosis and adsorption

A simple double fluorescence technique is described which allows quantification of cynomolgus monkey trabecular cell phagocytosis and adsorption. Within the first hour of exposure, significant adsorbance and minimal phagocytosis of polystyrene beads was observed. Peak internalization occurred at six hours after increasing linearly at a rate of 20% of maximum per hour; adsorbance was constant and minimal.

Maternal corneal thickness during pregnancy

We measured central corneal thickness in 89 pregnant women. It was increased 16 micron (P = .01) compared to the control eyes of 18 nongravid and 17 postpartum women. There was no significant difference (P = .79) in corneal thickness between the nongravid and postpartum groups. When comparing subjects by week of gestation, there was no trend over time in corneal thickness (analysis by linear regression). Intraocular pressure was lowered during pregnancy, but it did not correlate with corneal thickness for either the pregnant or nonpregnant group.

The cytoskeleton of the cultured human trabecular cell. Characterization and drug responses

To determine the organization of the three major cytoskeletal elements of cultured human trabecular meshwork cells (actin filaments, microtubules and intermediate filaments), we employed fluorescence microscopy and stereo-transmission electron microscopy of extracted, S-1 labeled and critical-point dried cells. Morphologic changes resulting from treatment with cytochalasin B, colchicine, taxol and nocodozole were also characterized. Compared with the cynomolgus monkey trabecular cell, morphologic differences in overall cell shape and orientation of both actin filaments and microtubules were noted. However, the responses to cytoskeletal active drugs were quite similar. Taxol, nocodozole and colchicine had a marked effect on microtubule organization, while nocodozole and colchicine had a marked effect on vimentin filament organization. None of these drugs produced marked changes in human trabecular cell shape. In contrast, treatment with the anti-actin drug cytochalasin B resulted in both a marked change in cell shape associated with organizational changes in all three cytoskeletal elements. These studies suggest a central role of actin filaments in determining overall cell shape and cytoskeletal organization in the cultured human trabecular cell.

The effect of refractive error on automated global analysis program G-1

We determined the effect of induced refractive errors on the visual field indices of the Octopus global analysis program G-1. After cycloplegia, refractive errors were introduced randomly in ten nonglaucomatous eyes of ten patients. Mean defect values (+/- S.D.) were lowest (2.4 +/- 0.8 dB) with full cycloplegic correction. With increasing ametropia, the mean defect increased significantly; it was 3.6 +/- 0.8 dB (P less than .0001) with the addition of +1.00 diopter and 5.3 +/- 0.9 dB (P less than .0001) with +2.00 diopters of sphere over the full cycloplegic correction. No significant differences in corrected loss variance, skew, short-term fluctuation, or reliability factor could be determined with changes in refractive error.

Adjusting the dose of 5-fluorouracil after filtration surgery to minimize side effects

The antimetabolite 5-fluorouracil (5-FU) was used as adjunctive treatment in glaucomatous eyes with poor prognoses undergoing filtering surgery. By adjusting the frequency of postoperative 5-FU subconjunctival injections according to the clinical response, the author thought it might be possible to reduce episcleral fibroproliferation and maintain a patent filter while reducing complications. Sixty-three eyes underwent filtering surgery with subsequent subconjunctival injections of 5.0 to 7.5 mg 5-FU for 14 days. The antimetabolite was not administered if there was evidence of corneal toxicity as demonstrated by epithelial defects or filaments, flat anterior chamber, or a conjunctival wound leak. By adjusting the injections in this fashion, the total amount of 5-FU administered ranged between 17.5 and 62.5 mg (34.4 +/- 11.6 mg). After 1 year, successful surgical outcomes were observed in 13/15 eyes with aphakia (87%), 11/17 eyes with neovascular glaucoma (65%), 11/12 eyes with at least two previous failed filters (92%), and 5/6 eyes with inflammatory glaucoma (83%). Eyes with epithelial downgrowth and cicatrizing diseases of the conjunctiva also were treated. Overall, conjunctival wound leaks were observed in 24% of the eyes and 29% had detectable changes in their corneal epithelium with corneal defects and filaments. Although adjusting the dose of 5-FU appears to be safe and effective, this can be determined clearly only by a controlled randomized clinical trial.