Key Concepts Genes represent the fundamental units of heredity. Identification of disease-causing genetic variants provides insight into pathogenesis of corneal disorders. Population-based and family-based studies allow researchers to identify disease-associated genetic variants. Genetic discoveries refine the classification of diseases historically…
Key Concepts Since specific ophthalmic microbiology testing is not available at all laboratories, ophthalmologists need to locate microbiology testing for their practices. Microbiology testing must be validated for ocular specimens. Laboratories, in general, are oriented to systemic treatment and may…
Key Concepts Dry eye disease (DED) is an umbrella term comprising a variety of clinical manifestations with differing underlying pathophysiologies. In patients presenting with DED, a comprehensive, systematic examination is needed; this should include medical history, symptom assessment, ocular surface…
Key Concepts Isolation of the layer or entity to be viewed is the key to slit lamp biomicroscopy. Techniques of biomicroscopic examination include diffuse illumination, broad beam illumination, optical section, indirect illumination, red reflex illumination, specular reflection, and sclerotic scatter.…
Key Concepts An anatomically and physiologically normal eyelid is vital in maintaining the health of the eye. Observing unconscious behaviors while collecting the patient’s history may provide valuable insight into underlying disorders. Examination should begin under ambient lighting prior to…
Key Concepts Four regions of the cornea are: (1) epithelium, (2) subepithelial zone (epithelial basement membrane, Bowman layer, superficial stroma), (3) stroma, and (4) endothelium and Descemet membrane. Six corneal responses are: (1) defects and their repair, (2) fibrosis and…
Key Concepts The eyelids function to cover, cleanse, and lubricate the eye. The eyelid skin is the thinnest in the body and allows for unrestricted movement. The tarsal plates provide structural stability to the eyelids. The orbicularis oculi is important…
Key Concepts Tear film stability is essential to maintaining ocular surface health. Lipids, mucins, and aqueous are the major components. There has been a shift from a strict three-layer model to understanding the tear film as a single dynamic functional…
Key Concepts The conjunctival and limbal epithelia are derived from surface ectoderm. The mucocutaneous junction at the lid margins is the junction between hydrophobic (unwettable) epidermis and hydrophilic (wettable) conjunctiva. The corneoscleral limbus is a unique stem cell niche microenvironment…
Key Concepts The principal physiologic role of the cornea is to allow external light to enter the eye and to contribute to its focusing on the retina. Thus transparency and refractive power are essential for this function. The cornea consists…