Ocular Cytopathology

An atlas that features the cytologic findings of the normal features and diseases of the eye.

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Wednesday, September 21, 2005

Chapter-3-page1

CHAPTER 3

External Disease of the Conjunctiva, Cornea, and Lacrimal Drainage System

Exfoliative ocular cytology has been used effectively to identify the cell types participating in conjunctival inflammation[1] and to identify specific infectious agents, such as chlamydia.[2] Unfortunately, exfoliative cytology of the cornea and conjunctiva is less reliable for the diagnosis of neoplastic conditions. In this chapter, the utility of cytology in external ocular diseases is addressed with illustrations of selected examples.

ACUTE CONJUNCTIVITIS

Acute bacterial conjunctivitis is one of the most common causes of a red eye. The clinical finding of a red eye with mucopurulent discharge is not specific and may be seen in other conditions, including allergic conjuncttivitis. While cultures are the best means to determine a specific etiologic agent, conjunctival cytology is a simple way to confirm an acute inflammatory response. However, conjunctival cultures have certain disadvantages. They are expensive. A positive culture may not indicate pathogenicity because bacteria normally inhabit the conjunctiva and eyelid. Because many bacterial conjunctival infections are self-limited, microbial cultures are frequently superfluous. Furthermore, topical antibiotics have a broad spectrum so that initial treatment is usually based on culture results. In acute bacterial conjunctivitis, cytologic preparations show epithelial cells and numerous segmented polymorphonuclear leukocytes (Figure 3-1). These findings are not specific for bacterial conjunctivitis, but simply indicate a marked acute inflammatory response.
Gonococcal conjunctivitis is noteworthy because it requires immediate systemic treatment. Clinical findings of gonococcal conjunctivitis usually include a red eye and characteristically an intense hyperpurulent discharge. Gram stain reveals gram-negative intracellular diplococci and sheets of neutrophils. Because the disease can be fulminant, initial treatment is predicated on the results of the gram stain.

ALLERGIC CONJUNCTIVITIS

Allergic conjunctivitis includes the clinical subsets of hay fever, atopic keratoconjunctivitis, vernal conjunctivitis, giant papillary conjunctivitis, and contact allergy. All of these disorders produce symptoms of intense itching and tearing. Enlarged conjunctival papillae are seen on clinical examination (Figure 3-2).
Hay fever is the most common form of allergic conjunctivitis.[3] It is seasonal in character, mild in intensity, and shows no corneal involvement.
Atopic keratoconjunctivitis has been associated with atopic dermatitis,[4] occurs in the late teens, shows greater enlargement of papillae in the lower palpebral conjunctiva than in the upper tarsal conjunctiva, and often exhibits eyelid swelling and maceration.[5]
Vernal conjunctivitis is characterized by a seasonal predilection, propensity for elevated large cobblestone papillae of the upper tarsal conjunctiva, and grey limbal nodules called Horner-Trantas dots,[6] that are collections of eosinophils (Figures 3-3 and 3-4).

References:
1. Herbert H. Pathology and diagnosis of spring catarrh. Brit Med J 1903;2:735.
2. Duggan MA et al. Acta Cytolog. 1986
3. Friedlaender MH et al. Arch. Opthalmol. 1984
4. Hogan MJ. Am J Opthalmol. 1953
5. Donishik PC. Allerfic conjunctivitis. 1988
6. Trantas A. Le catarrhe printanier en Turquie. Arch Opthalmol 1953 (Paris) 1905;25:717-731




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