Ento Key

Definition Infection of varicella (chickenpox) in the ophthalmic division of the trigeminal dermatome most frequently affecting the nasociliary branch. Key Features • Herpes zoster ophthalmicus can affect any of the…

Definitions • Corneal cross-linking (CXL) is a procedure combining corneal saturation with riboflavin and exposure to UV light to increase the amount of links between collagen fibers in the corneal…

Definition Wavefront-customized excimer laser refractive surgery corrects pre-existing lower- and higher-order aberrations. Wavefront-optimized treatments preserve pre-existing corneal optical aberrations (customizing for spherical aberration). Key Features • Zernike polynomials and Fourier…

Definition Refractive errors may be corrected by means of spectacles, contact lenses, orthokeratology, intraocular lens implants, and keratorefractive surgery. Key Features • Spectacle lens advantages: inexpensive; suitable to correct myopia,…

Definition The neutralization of an individual’s refractive error using a variety of tests in which the patient’s responses determine the lens power that best produces a sharply focused image on…

Definition An aberration is any deviation of the path of a ray of light from geometrically ideal behavior. Key Features • Aberration theory is strictly confined to geometrical optics and…

Definitions Light – Electromagnetic energy detectable by the eye. Geometrical Optics – The properties of light governed by propagation in straight lines, refraction, and reflection. Physical Optics – The properties…

Definition The classic optics of the eye are best understood in terms of the optical characteristics of its components—the cornea, pupil, crystalline lens, and retina—and how they function in combination….

Definition The molecular mechanisms underlying selected inherited eye disorders as defined by the responsible genetic mutations. Key Features • Inherited disorders affecting the ocular anterior segment. • Genetic defects causing…