Bulbar conjunctiva

Chemosis Edema of the bulbar conjunctiva, forming a swelling around the cornea. 

These include absorption by adjacent palpebral and bulbar conjunctiva, with concomitant rapid removal from ocular-tissues by peripheral blood flow. For example, the extensive vascularity of the uvea underlies the bulbar conjunctiva, a mucous membrane, and the sclera, a white tissue providing a tough outer covering [177]. Binding of drug to either external sites, like the tear polymers such as mucins or lysozyme, or internal tissues like the sclera can be detrimental to efficacy. 

Redness (refers to palpebral and bulbar conjunctivae excluding cornea and iris)... 

Inflammatory conditions Treatment of steroid-responsive inflammatory conditions of the palpebral and bulbar conjunctiva, lid, sclera, cornea, and anterior segment of the globe, such as Allergic conjunctivitis acne rosacea superficial punctate keratitis herpes zoster keratitis iritis cyclitis and selected infective conjunctivitis (when the inherent hazard of steroid use is accepted to obtain an advisable diminution in edema and inflammation [prednisolone]) vernal conjunctivitis episcleritis epinephrine sensitivity and anterior uveitis. 

Fig. 7.1 Front view of the right eyeball. 1, Upper eyehd crease 2, Cornea 3, Pupil 4, Iris 5, Lower eyehd margin 6, Bulbar conjunctiva 7, Lacrymal caruncle 8, Lacrymal meatus 9, Lacrymal caniculus 10, Lateral canthus...

Fig. 7.2 Horizontal section of the eyeball via the fovea centralis (Some extraocular structures are mentioned). 1, Levator muscle 2, Orbicularis oculi muscle 5, Eyelid skin 4, Palpebral conjunctiva 5, Bulbar conjunctiva 6, Superior tarsal plate 7, Upper eyelid margin 8, Cornea 9, Conjunctival sac 10, Sclera...

The preferred site for the instillation of eyedrops is the lower conjunctival sac (cul-de-sac). The anterior wall of this sac is the conjunctiva of the lower eyelid (palpebral conjunctiva), whereas the conjunctiva that covers the eyeball (bulbar conjunctiva) forms the posterior border, and the forniceal conjunctiva (the conjunctival bridge between bulbar and palpebral parts) lines the crater and the lateral borders of this space (Figure 24.1). 

FIGURE 24.1 Ocular and periocular tissues. EL, eyelid DD, drug droplet COR, cornea AC, anterior chamber PC, posterior chamber AOF, aqueous outflow tract (trabeculum meshwork and Schlemm canal) BCNJ, bulbar conjunctiva PCNJ, palpebral conjunctiva FCNJ, fornical conjunctiva FNX, fornix (conjunctival sac/cul-de-sac) SC, sclera IR, iris CB, ciliary body CHOR, choroid RET, retina ONH, optic nerve head V, vitreous L, lens Z, lens zonulae ORF, orbital fat. 

In addition to the corneal route, topically applied ocular drugs may be absorbed via a noncorneal absorption route that involves drug transport across the bulbar conjunctiva and underlying sclera into the uveal tract and vitreous humor.65 The intercellular spaces of the conjunctival epithelium are wider than those of the corneal epithelium. As a result, the conjunctiva has higher permeability than the cornea to agents such as mannitol, inulin, and FITC-dextran.86 The penetration of peptides, however, is limited by enzymatic degradation.87 The limit of molecular size for conjunctival penetration is between 20,000 and 40,000 Da. Vitreous can act as an aqueous and unstirred diffusion barrier to drug permeation.64... 

Figure 1-1 Self-induced injury. Fluorescein staining of the inferior bulbar conjunctiva shows a typical epithelial defect caused by contact with an ointment tube tip. (From Solomon A. Inadvertent conjunctival trauma related to contact with drug container tips. Ophthalmology 2003 110 798.)...

With the patient looking down and the upper lid retracted, a drop of solution is applied to the superiorly exposed bulbar conjunctiva. 

For administration, the drug-impregnated paper strip is moistened with a drop of normal saline or extraocular irrigating solution, and the applicator is gently touched to the superior or inferior bulbar conjunctiva or to the inferior conjunctival sac.To avoid the risk of cross-contamination between eyes, practitioners should use separate applicators for dye delivery to eyes with suspected infection. 

Figure 23-5 Inflammation of temporal bulbar conjunctiva and excoriation of outer canthus arrow ), characteristic of angular blepharoconjunctivitis.

The conjunctiva proceeds onto the globe from the fornix to form the bulbar conjunctiva, which overlies Tenon s capsule and merges with the limbal cornea. Loosely attached to the capsule over the entire globe, the bulbar conjunctiva forms a homogeneous layer of stratified squamous epithelium at the limbus and contains many goblet... 

Acute S. aureus conjunctivitis occurs less commonly than does chronic staphylococcal conjunctivitis. It is usually characterized by inferior palpebral conjimctival hyperemia with a mucopurulent discharge. In many cases the bulbar conjunctiva beneath the eyelid is more hyper-emic than is the exposed bulbar conjunctiva. The presence of staphylococcal exotoxins may cause SPK and marginal corneal infiltrates that frequently accompany the conjunctivitis (Figure 25-4C). 

S. pneumoniae is a common cause of acute bacterial conjunctivitis in children (Figure 25-5). Concurrent upper respiratory tract infections and otitis media, especially in children younger than 4 years, are common. In moderate climates S. pneumoniae is often the cause of acute bacterial conjunctivitis epidemics. This condition commonly presents with diffusely scattered petechial hemorrhages, especially on the superior bulbar conjunctiva, a mucopurulent discharge in the lower fornix, and transient marginal corneal infiltrates. Pseudomembranes may form. 

In its early stages trachoma presents as a chronic follicular conjunctivitis with a predilection for the superior tarsal and bulbar conjunctiva. Over time, the conjunctival reaction becomes papillary in nature and, with the inflammatory infiltration that occurs, the follicular character of the infection can become obscured. Patients experience symptoms of photophobia, tearing, and mucoid or mucopurulent discharge. Limbal edema and superior bulbar conjunctival hyperemia also may occur. Conjunctival follicles that form at the limbus are characteristic of severe trachoma. Primary corneal involvement often includes superior epithelial keratitis and superficial superior pannus formation. A wide variety of corneal infiltrates... 

The term pterygium means wing, which is descriptive of its typical appearance in most patients. Pterygia are primarily located in the interpalpebral area and more frequently occur in the nasal aspect of the bulbar conjunctiva. They appear as a wedge-like structure with its base toward the medial or lateral canthus and its apex toward the corneal surfece (Figure 25-35). 

Lehr, Lee, and Lee ° investigated two gentamicin formulations of polycarbophil (neutralized vs. non-neutralized) to pigmented rabbit eye. Both polymeric formulations doubled the uptake of gentamicin by the bulbar conjunctiva. 

Injection of soluble drug under the dorsal bulbar conjunctiva results in transient leakage of the dmg from the injection port onto the ocular surface. However, the bioavailability on the ocular surface of subconjunctivally injected dmgs is likely to be highly unpredictable in the horse and this route should not be used alone as a means of delivering topical medication. In general, where used to supplement direct topical instillation, subconjimctival injections require to be repeated every 12-36 h. 

Injection of hydrophilic drugs under the bulbar conjunctiva results in direct diffusion of relatively high levels of the drug into the anterior chamber, comeal stroma, posterior chamber and anterior vitreous. In the horse, the route is used most frequently to manage acute anterior segment disease or, using depot corticosteroid preparations, in the management of anterior uveitis uncomplicated by comeal ulceration. 

To evaluate the distribution and metabolism of [3H] tafluprost in ocular tissues and to study the IOP-lowering effects of the major metabolites of tafluprost, single ocular doses of [3H]tafluprost were administered to male/female cynomolgus monkeys (1 pg/eye for tissue distribution studies and 10 pg/eye for metabolic studies) [46]. Tafluprost was rapidly absorbed into ocular tissues and subsequently entered the systemic circulation. The highest concentrations of radioactivity were observed in the bulbar conjunctiva and the palpebral conjunctiva (323 and 180ng-eq/g, respectively) at 0.083 h after administration, and in the cornea (784ng-eq/g) at 0.25 h after administration. Nonvolatile radioactivity in plasma peaked (0.907 ng-eq/g) at 0.083 h after administration and then declined steadily. Three major metabolites shown in Figure 2.7, a carboxylic acid of tafluprost (AFP-172), 1,2-... 

In humans, the adult eyeball measures approximately one inch (2.5 centimeters) in diameter, and of its total surface area, only the anterior one-sixth is exposed to the external environment. This exposed area is protected by accessory structures of the eye, including the eyelids, eyelashes, eyebrows, lacrimal (tearing) apparatus, and extrinsic eye muscles. Each eyelid possesses a conjunctiva, which is a thin, transparent, and protective mucus membrane. The conjunctiva lines the inner aspect of the eyelids as the palpebral conjunctiva and folds back (reflects) over the eyelids onto the anterior exposed surface of the eyeball as the bulbar (ocular) conjunctiva. The bulbar conjunctiva covers only the white of tlae eye (not the cornea that covers over the iris and pupil). Because tlie bulbar conjunctiva is quite thin, blood vessels are clearly visible beneath it. When these blood vessels are dilated and congested from local irritation or infection (conjunctivitis, or inflammation of the conjunctiva), the result is the appearance of reddened and irritated bloodshot eyes. 

Dexamethasone is a steroid antibiotic combination. Tobramycin inhibits bacterial protein synthesis, causing death dexamethasone suppresses the inflammatory response. The combination is indicated in superficial bacterial ocular infection or risk of bacterial ocnlar infection inflammatory conditions of palpebral and bulbar conjunctiva, cornea, and anterior segments of globe where inherent risk of steroid use in certain infective conjunctivitis is accepted to obtain a diminution of edema and inflammation chronic anterior uveitis and comeal injury from chemical, radiation, or thermal bums, or penetration of foreign bodies, where risk of superficial ocular infection is high, or an expectation, or when potentially dangerous numbers of bacteria will be present in the eye. 

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