The three types of illumination that are used most to examine the eye prior to a contact lens fitting are diffuse, direct and indirect illumination.
The best method for examination of the endothelium is sclerotic scatter.
False: Specular reflection is used for examining the endothelium. Sclerotic scatter is used to observe disturbances in corneal transparency, deposits, scars or other opacities and edema.
In order to focus the slit lamp, hold the joystick forward as far as possible, and then pull it back toward you to focus the slit of light on the cornea.
False: Begin by holding the joystick back as far as possible, and then move forward until the slit of light is sharply focused on the cornea.
Iris transillumination and retroillumination from the fundus are usually performed in conjunction with pupil dilation.
Tangential Illumination is the only illumination that can be observed with the naked eye rather than through the oculars.
False: Sclerotic scatter is the illumination that can be observed with the naked eyes. Tangential illumination must be observed through the oculars, as must all other illuminations. It is effective in determining raised areas on the iris as in tumors and it is used as an adjunct technique in determining glaucoma.
Sclerotic scatter is the only illumination that can be observed with the naked eye rather than through the oculars.
True: This is advantageous for a general view of the cornea.
All of the following are forms of direct focal illumination: optical sectioning, proximal illumination, diffuse, specular reflection, and sclerotic scatter.
Since retroillumination is formed by light reflecting from behind, surface deposits, scars or anything else that is raised shows well using this lighting.
True: This illumination is used to observe curling edges in a soft lens, bevels and edge quality in rigid lenses and, also, allows vascularization to be seen.
Sclerotic scatter is the illumination typically used to detect edema
True: Once the illumination has been set up, the examiner views the cornea with the naked eye and not through the oculars, unless the slit lamp has been taken out of click stop. Edema appears as a grayish-white cloudy area of opaqueness.
The illuminated targets of known size reflected back from the corneal surface in a keratometer or ophthalmometer are referred to as the corneal cap.
False: The illuminated targets are called mires. The corneal cap is the 3mm to 5 mm most central zone of the cornea. It is the steepest curvature on the cornea.
What form of illuminations are useful in detecting a variety of corneal anomalies such as edema, abrasions, scarring, striae, neovascularization, keratitis, keratoconjunctivitis, ulcers, erosions & degenerations, etc.
Match to the image:
Specular reflection, Diffuse, Sclerotic scatter, Direct-focal, Indirect, Retroillumination
5. Specular Reflection
6. Sclerotic Scatter
2. Direct Focal