Manahan, Maclester T. OP 1-1
Object of interest is illuminated only by light
reflected from the structures behind it.
Vary angle of illumination
Moderately wide beam
Slit beam is offset
Medium to high magnification
Reflected light from iris or fundus
1. Assessment of pupils and all parts of the
transparent ocular media (tear film, cornea,
aqueous, lens, and vitreous).
2. Used to observe whether the opacity is
-Obstructive – Opaque to light
-Respersive – Scatters light
-Refractile – Refracts, minimizes or distorts the
views of background.
3. Observe anterior capsular changes
-Deposits, Foreign bodies, Opacities Below
The observed feature on the cornea is viewed in
the direct pathway of reflected light. The angle
between the microscope and the illuminating arm
is about 60°.
The angle between the microscope and slit-lamp
arms is greatly reduced or increased so that the
feature on the cornea is viewed against a dark
background. It may be necessary to uncouple the
Alignment of reflected beam
with area under observation
Direct and full view
Margin or edge
Look to the side of the corneal block
Objects viewed may have one color in direct and
a different color with retroillumination.
The object (observed structure) is viewed in the
direct pathway of the reflected light. The
illuminated background is directly behind the
The object (observed structure) is not viewed in the direct
pathway of the reflected light. The retro-illumination object is
viewed against a dark non-illuminated background. The
reflecting illuminated surface is to one side of the axis of
Limbal vessel engorgement seen with retroillumination and very high magnification. This may
be a prelude to vascularization.
Vascular ingrowth into the cornea arising from a
vaso-proliferative stimulus..Observe the looping and
branching limbal vessels seen against the illuminated
background of the clear cornea.
Lipoidal deposition on the lens surface, common with
high water content hydrogel lenses.