Test 7
1. True statements about slit-lamp include:
a. contains two convex lenses separated by a distance greater than the sum of their focal 
b. the image formed is real, erect and magnified
c. Porro prism is found in the slit-lamp to invert the image formed
d. Porro prism in the slit-lamp reduces the length of the microscope
e. variable magnification can be achieved by using zoom lenses.
2. The following are true about the direct ophthalmoscope:
a. the retina image of a hypermetropic patient appears smaller than that of a myopic patient
b. a divergent beam of light is used to illuminate the patient's retina
c. a -2.00D observer (without glasses) who needs +2.00D lens to examine a patient 
    (without glasses on) suggests that the later is hypermetropic.
d. up to X15 magnification can be achieved 
e. it is a sensitive tool for detecting macular oedema

3.In slit-lamp examination:

a. specular reflection is useful in examining the corneal endothelium
b. the angle of incidence and reflection are equal in specular reflection
c. total internal reflection is used in sclerotic scatter
d. in retroillumination, a secondary light source is used to illuminate a more anterior surface
e. corneal oedema is best highlighted with retroillumination
4. With regard to von Helmholtz keratometer:
a. it uses the first Purkinje-Sanson image
b. the image is real, erect and magnified
c. it uses a circular object of known size and distance 
d. the image size varies with corneal curvature. 
e. Wollaston prism is used to produce image doubling.

5. In indirect ophthalmoscope:

a. the illumination and viewing axes are co-axial.
b. as the condensing lens is moved away from the patient, the image size is determined by 
    the refractive status of the patient.
c. the higher the power of the condensing lens, the smaller the image size
d. the field of illumination is wider in myopes than hypermetropes
e. the field of vision is wider with a +20D condensing lens than +30D lens.

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