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PubMed1991

[Choroidal detachment associated with rhegmatogenous retinal detachment and aqueous flare].

The aqueous protein level (APL) in eyes of rhegmatogenous retinal detachment (RRD) combined with or without choroidal detachment (CD) was investigated using a laser flare-cell meter. The APL in eyes of RRD with CD was 70 times higher than in eyes of simple RRD. The APL increased suddenly with the appearance of CD and decreased rapidly in accordance with the disappearance of CD. The longer the CD continued, the higher the APL remained preoperatively as well as postoperatively. The APL in eyes of RRD with CD was still twice as high as in eyes of simple RRD 6 months after successful retinal reattachment. This marked and prolonged intraocular inflammation in eyes of RRD with CD might result in a poorer visual outcome. The extremely high APL might be caused by reflux of suprachoroidal protein through the uveoscleral route and/or venous protein through the trabecular meshwork due to ocular hypotony and possibly by diffusion of protein via posterior chamber and vitreous cavity due to the breakdown of the blood-ocular barrier.

Adult↗
PubMed1991

Response of argon laser trabeculoplasty with varying anterior chamber anatomy.

We studied one randomly selected eye of 50 consecutive primary open-angle glaucoma patients treated with argon laser trabeculoplasty to assess response differences as functions of anterior chamber anatomy and refraction. We found no significant differences related to these variables, and thus conclude that argon laser trabeculoplasty may be performed successfully in patients with crowded angles as long as the trabecular meshwork can be visualized.

Anterior Chamber↗
PubMed1991

Angle closure glaucoma precipitated by aerosolized atropine.

Angle closure glaucoma is an infrequent form of glaucoma occurring when the filtration mechanism for the aqueous humor is obstructed by apposition of the peripheral iris to the trabecular meshwork. Anatomic features associated with acute-angle closure include congenitally small anterior segments, increased lens thickness, and shallow anterior chamber depth. We present two patients who developed signs and symptoms of angle closure glaucoma after receiving aerosolized atropine for treatment of chronic obstructive pulmonary disease. We recommend that before instituting therapy with an inhaled anticholinergic agent, the patient should be questioned concerning prior history of angle closure glaucoma symptoms and signs and the anterior chamber depth should be examined using iris illumination. Patients having shallow anterior chambers, or possible prior angle closure glaucoma attacks, should be examined by an ophthalmologist before inhalant anticholinergic therapy.

Administration, Inhalation↗
PubMed1991

[Internal sclerostomy with a high-powered argon laser].

A full-thickness sclerostomy from the anterior chamber to the subconjunctival space was created in 9 eyes of 7 rhesus monkeys using an argon endolaser. After the injection of sodium hyaluronate into the subconjunctival space and the anterior chamber, a 300 microns fiberoptic fiber coupled with an argon laser (HGM, model 20) was inserted to the anterior chamber and positioned at the trabecular meshwork. A patent sclerostomy was created in all 9 eyes by 1 to 3 laser pulses with an energy of 4W with a duration of 0.5 second. Preoperative intraocular pressure in treated eyes and untreated eyes, measured with a pneumatic tonometer, was the same. After one month, the intraocular pressure of the treated eyes was 4.6 +/- 0.4mmHg lower than that of the untreated eyes. Histologic study revealed that the sclerostomies with a diameter of 200-300 microns from the anterior chamber opening to the subconjunctival space were patent at one month after the treatment. Internal sclerostomy with a high powered argon endolaser may hold potential as a new filtering procedure which can easily be performed with a minimum of conjunctival damage.

Animals↗
PubMed1991

Immune response to Staphylococcus aureus endophthalmitis in a rabbit model.

Staphylococcus aureus is an important cause of severe bacterial endophthalmitis. Both immunoglobulin (Ig) G and A antibody titers to ribitol teichoic acid (RTA), the major antigenic determinant of the S. aureus cell wall, were measured by an enzyme-linked immunosorbent assay in serum, tears, aqueous, and vitreous on days 3, 7, 10, 14, 21, and 30 after intravitreal injection of viable S. aureus in rabbits. Clinical examination showed vitreous opacification in all rabbits from days 7-30. Histopathologic examination showed acute inflammation on day 3 and chronic inflammation on days 7-30 in the conjunctiva, cornea, iris, ciliary body, and trabecular meshwork. The vitreous cavity contained neutrophils and necrotic cells on all days. Retinal necrosis was present on days 14-30. Lymphoid follicles with plasma cells were identified in the conjunctiva, ciliary body, and choroid. The vitreous of experimental eyes showed increasing numbers of bacteria from days 3-14, followed by a decrease in numbers on day 21 and absence of viable bacteria on day 30. Increases in IgG antibody levels to RTA were first detected in serum where they were higher than in tears, aqueous, and vitreous until day 14. Vitreous IgG antibody levels to RTA in experimental eyes exceeded all other samples on day 14 and progressively increased thereafter; the other samples declined. The IgA antibody levels were increased in tears on day 14 and in the vitreous of experimental eyes on days 14, 21, and 30. Vitreous IgG antibody levels to RTA were substantially higher than vitreous IgA antibody levels. An inverse correlation was found between vitreous IgG antibody levels and positive vitreous cultures, suggesting that the humoral immune response may be important in the spontaneous sterilization of the vitreous in this model.

Animals↗
PubMed1991

High-voltage electron microscopy of normal human cornea.

Conventional transmission electron microscopy (CTEM) was compared with high-voltage electron microscopy (HVEM) on 11 normal human corneas (age range, 30 weeks of gestation to 92 yr). Epithelial anchoring fibrils were noted between the basal epithelial cells and Bowman's layer (BL) as previously reported. Parallel pairs of fibers, 27.5 nm in diameter, were observed crossing into the anterior stromal lamellae from BL; their termination sites, however, were not identified. The lateral termination of BL was marked by the presence of a keratocyte lying directly below the end of the multilaminar basal lamina. In this region, BL tapered and became interwoven with the scleral collagen fibrils in the substantia propria. The HVEM accentuated the orthogonal relationship of collagen bundles apparently emerging from the stromal keratocytes. The posterior corneal stroma appeared to be attached to the anterior surface of Descemet's membrane (DM) by fibers 22.3 nm in diameter that were associated frequently with a dense amorphous material. In the periphery, DM tapered to a thin strand, 0.5 microns in thickness, containing cable-like strands of banded collagen. The posterior nonbanded portion continued laterally and anteriorly in a series of folds between the fibrous collagen sheets of the anterior trabecular meshwork. In addition, HVEM enhanced the visibility of extracellular matrix interactions in the lateral terminations of BL and DM, attachment fibers from BL to the stroma and from the stroma to DM, and keratocyte and collagen fiber orientations not seen easily by CTEM.

Adolescent↗
PubMed1990

Internal sclerostomy with argon contact laser--animal experiment using 5-fluorouracil.

A full-thickness sclerostomy was carried out with an ab interno approach, using an argon endolaser, in 9 eyes of 7 rhesus monkeys. After the injection of sodium hyaluronate into the subconjunctival space and the anterior chamber, a 300 micron fiber optic probe coupled with a water-cooled argon laser was inserted into the anterior chamber through the corneal incision made by a 23-gauge needle and positioned on the trabecular meshwork opposite to the corneal incision. A patent sclerostomy was obtained in all 9 eyes by 1 to 3 laser pulses with an energy of 4 W and a pulse duration of 0.5 seconds. After the surgery, 0.1 ml of 5-fluorouracil was injected subconjunctivally every day for one week. Intraocular pressure (IOP) was determined by pneumatic tonometer for one month at appropriate intervals. Mean preoperative IOP was 22 mmHg in both operated and nonoperated eyes. After one month IOP was 4.6 +/- 0.4 mmHg lower in the operated eyes than in the nonoperated eyes. Histologic study revealed that the sclerostomies from the anterior chamber opening to the subconjunctival space with the diameter of 200-300 microns still remained patent one month after surgery. Ab interno sclerostomy with an argon endolaser would be useful as a new filtering procedure which can easily be performed with minimum conjunctival damage.

Animals↗
PubMed1990

Acute angle-closure glaucoma in a patient with acquired immunodeficiency syndrome successfully treated with argon laser peripheral iridoplasty.

Laser iridectomy relieves pupillary block and is the procedure of choice for angle-closure glaucoma. Since not all cases of angle closure glaucoma are due to this mechanism, iridectomy is not always curative. Argon laser peripheral iridoplasty causes a contraction of peripheral iris away from the trabecular meshwork, and is useful in these circumstances. We successfully treated bilateral acute angle-closure glaucoma in a patient with acquired immunodeficiency syndrome with this procedure.

Acquired Immunodeficiency Syndrome↗
PubMed1989

A latent collagenase in human aqueous humor.

It has been suggested that the trabecular meshwork may be involved in the pathogenesis of open-angle glaucoma, and some authors have pointed out that disorders of the extracellular matrix components may play a role; nevertheless, nothing is known about the normal metabolism of connective tissue molecules in this particular tissue. We recently initiated some studies in this field and have focused on the in vitro effects of aqueous humor on collagen metabolism. We report the finding of a latent collagenase of low molecular weight in aqueous humor obtained from cataractous patients; the enzyme was identified through several methods, including its in vitro activity against radiolabelled type I collagen and additionally with a zymogram technique. It was partially characterized by high-performance liquid chromatography.

Aqueous Humor↗
PubMed1985

Quantitation of uveoscleral outflow in normotensive and glaucomatous Beagles by 3H-labeled dextran.

In uveoscleral outflow, aqueous humor leaves the anterior chamber and passes caudally through the trabecular meshwork and the sclerociliary cleft to enter the supraciliary and suprachoroidal spaces. The fluid is then absorbed by choroidal and scleral circulations. Using 3H-labeled dextran, uveoscleral outflow was quantitated in normotensive and glaucomatous Beagles under general anesthesia. The intrascleral plexus was isolated and 3H-labeled dextran was injected into the anterior chamber. Intrascleral plexus contents were sampled every 5 minutes over a 30- to 60-minute period. The eyes were enucleated, sectioned, and prepared for scintillation counting. Uveoscleral outflow accounted for 15% and 3% of the total aqueous humor outflow in the normotensive dogs and in the advanced glaucomatous dogs, respectively. In the advanced glaucomatous Beagle, conventional and uveoscleral outflow pathways were reduced and contributed to the etiopathogenesis of glaucoma.

Animals↗
PubMed1989

[Effects of an anti-prostaglandin agent added to the irrigation solution on damage to the anterior segment in monkey eyes induced by pars plana vitrectomy].

Flurbiprofen is a water-soluble, non-steroid anti-inflammatory agent and is capable of marked inhibition of prostaglandin synthesis. In a previous study by the authors, it was determined that the optimum concentration of flurbiprofen for intraocular irrigation solution in monkey retinas is 4 to 40 micrograms/ml. The present study was conducted to determine the optimum concentration of flurbiprofen for the irrigation solution, as well as to evaluate its toxic effects on the anterior segment tissues. In a pilot experiment, flurbiprofen was injected directly into the anterior chamber of pigmented Japanese rabbits to investigate its overall toxicity and to quantify the concentration at which it could become toxic to the cornea. This experiment showed that aqueous concentrations of flurbiprofen greater than 1,000 micrograms/ml were toxic. In a subsequent study, the twelve eyes of six Japanese monkeys (Macaca fuscata) underwent vitrectomy using balanced salt solution (BSS) containing concentrations of flurbiprofen from 4 to 800 micrograms/ml and BSS alone. This experiment showed that BSS containing 4 to 100 micrograms/ml of flurbiprofen prevented post-operative occurrence of edema in non-pigmented epithelial cells in the ciliary body. Furthermore, it was observed that infiltration of inflammatory cells into the trabecular meshwork and swollen mitochondria in the corneal endothelial cells were likewise prevented. This is thought to be due to the pharmacological action of flurbiprofen; which has an inhibitory effect on leucocyte migration and prostaglandin synthesis as well as stabilization of the cell membrane. However, these effects were not observed in the eyes vitrectomized with flurbiprofen concentrations between 400 and 800 micrograms/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Optic disc measurements with computerized image analysis in experimental chronic glaucoma].

We quantitatively analyzed morphological changes of the optic disc of ten Japanese monkey eyes exposed to sustained intraocular pressure (IOP) elevation by repeated argon laser application to the trabecular meshwork. Using a computerized image analyzer (Topcon IMAGEnet), we measure the cup-disc ratio (CDR), disc area (DA), cup volume/disc area (CV/DA), and rim area/disc area (RA/DA). The duration of IOP elevation was 48.4 +/- 0.8 (mean +/- SD) weeks, and the mean IOP during the experiment was 26.3 +/- 2.6 mmHg [the mean IOP during the experiment/pre-treatment IOP was 2.05 +/- 0.55 (IOP ratio)]. In advanced glaucomatous eyes (the duration of IOP elevation of approximately one year), comparing pretreatment, the CV/DA increased 4.96 times, the vertical CDR increased 1.78 times, the horizontal CDR increased 1.69 times, the DA increased 1.42 times, and the RA/DA decreased 0.54 times. A significant positive correlation was found between the IOP ratio and, both the vertical CDR (gamma = 0.65) and the CV/DA (gamma = 0.68). These results suggested that the development of glaucomatous optic disc cupping correlated with the degree of IOP elevation in monkey eyes. Using this computer image analyser, the longitudinal quantitative follow-up of disc changes of experimental glaucoma may be useful for understanding the mode of human glaucomatous optic nerve damage.

Animals↗
PubMed1989

Laser trabeculoplasty retreatment.

Thirty-seven eyes of 30 patients classified as late treatment failures following 360 degrees of argon laser trabeculoplasty (ALT) underwent retreatment of the trabecular meshwork. Retreatment was considered successful if the intraocular pressure was maintained at 21 mm Hg or below and if the visual fields and optic nerve remained stable. By the Kaplan-Meier survival analysis the rates of success were: 100% at 3 months, 91% at 6 months, 77% at 9 months; 70% at 1 year, and 47% at 16 and 20 months. The mean decrease in intraocular pressure 1 month after retreatment was 6.5 +/- 4.9 mm Hg (from 23.9 to 17.5). Three patients followed for 3 years or longer had a mean decrease of -5.67 mm Hg. Repeat argon laser trabeculoplasty appears to be a reasonable treatment option for selected patients who are late failures after initial treatment.

Aged↗
PubMed1989

Pattern-evoked potentials and optic nerve fiber loss in monocular laser-induced glaucoma.

ERG and VEP responses to counterphase checkerboard stimuli were obtained from cynomolgus monkeys with monocular glaucoma induced by laser photocoagulation of the trabecular meshwork. The glaucomatous eyes showed reductions of PERG amplitude that were directly related to the histologically defined nerve damage. VEP amplitudes were also reduced in the glaucomatous eyes, but were more variable and less affected by damage than the PERG responses. An acute increase in eye pressure to 40 mm Hg in eyes without damage had no detectable effect on PERG amplitudes.

Animals↗
PubMed1988

A re-evaluation of corneal development.

The corneal epithelium is initially a continuation of the surface ectoderm, but later on in development appears to arise from the superficial cells of the corneal stroma. The corneal epithelium varies in thickness depending on the status of the lids, viz either fused or open. When the lids are fused, the epithelium is only 2 to 3 layers in depth. When the lids are separated, a basement membrane is distinguishable and the epithelium is 4 to 5 layers in depth. Bowman's membrane develops from processes of the superficial mesenchymal cells of the stroma that become thickened and are arranged in the long axis of the corneal surface. The corneal stroma develops from in situ mesenchymal tissue and does not migrate from the limbal mesenchymal tissue. The attenuation of the central cornea, early in development, is due to the impingement of the lens against the developing cornea. The central constriction of the cornea has led previous observers to believe that the stroma migrates from the peripheral limbal area towards the center of the cornea. Descemet's membrane arises from processes of the deep mesenchymal cells of the corneal stroma. These processes thicken and become arranged in the long axis of the posterior surface of the cornea. The membrane is initially cellular, and well-defined septae are noted between the cells. With maturity, Descemet's membrane becomes a homogeneous structure. The endothelium is derived from the mesenchymal cells of the posterior stroma. These cells are initially cuboidal but then become flattened. During the early development of the cornea, the tunica vasculosa lentis may play an important role. It is suggested that the anterior chamber is maintained early on by a transudate from the vessels of the tunica vasculosa lentis. The vessels of the tunica vasculosa lentis are compressed by the vanguard of the optic cup against the equator of the lens. With regression of this vascular system, there is a simultaneous development of aqueous humor. The hydrodynamic force of aqueous production assists corneal molding by a vis a tergo affect. Pari passu with this hydrodynamic force, the corneal stromal fibers increase in length and width. The structures involved in aqueous humor production, viz the ciliary epithelium, and the aqueous humor drainage, viz the filtration angle, trabecular meshwork and aqueous veins, develop contemporaneously as the tunica vasculosa lentis regresses. The limiting and fixed stabilizing site is at the limbus, the site of insertion of the rectus muscles. At these sites a dimpling occurs as the cornea is enlarging.

Cornea↗
PubMed1988

Ophthalmic irrigants: a current review and update.

The search for an ideal intraocular irrigating solution is of paramount importance to te ophthalmic surgeon. An intraocular irrigating solution, as well as surgical technique, can have deleterious effects on ocular tissues. Since an intraocular irrigating solution comes in contact with the cornea, lens, trabecular meshwork, uvea, vitreous, and retina, and ideal irrigant would be ome that ensures biological function for all of these tissues. In a practical sense, the best irrigant is one that causes the least possible damage to the structural integrity and function of the intraocular environment. This paper summarizes the development, uses, and efficacy of intraocular irrigating solutions as currently used during intraocular surgery.

Animals↗
PubMed1988

Calcitonin gene-related peptide immunoreactive nerves in human and rhesus monkey eyes.

Using immunohistochemical methods, calcitonin gene-related peptide localizes to peripheral nerve fibers of the human and rhesus monkey eye. Immunoreactive nerve fibers are found in the cornea, about limbal blood vessels and in the trabecular meshwork. Many immunoreactive iris nerve fibers are present, mostly within the stroma. A particularly dense network occurs just anterior to the iris sphincter muscle, but only a small number of immunoreactive nerve fibers are visualized within it. The ciliary muscle and ciliary processes also are innervated. Immunoreactive nerve fibers are associated with uveal blood vessels, most prominently in the choroid and ciliary body. Apposition of immunoreactive nerve fibers to uveal melanocytes is seen. In lower mammalian species, calcitonin gene-related peptide co-localizes with substance P in many ocular nerve fibers. The comparative distribution in human and monkey eyes of nerve fibers immunoreactive to these two peptides is discussed.

Adolescent↗
PubMed1987

Contact laser: thermal sclerostomy ab interna.

An experimental technique utilizing a sapphire contact laser probe for thermal sclerostomy ab interna is described. The contact laser probe with a tip diameter of 0.2 mm is brought in contact with the trabecular meshwork. Using 3.50 watts of cw Nd:YAG at 0.1 second duration, three to five exposures established communication between anterior chamber and subconjunctival space in pigmented rabbits.

Animals↗