The Retinal Diagram Window

The Retinal Diagram window is where the shape of the tumor base and other anatomic landmarks of interest are digitized. Photographs of the inner surface of the eye can be displayed in this window to assist the digitization. This window is also where the height and shape of the tumor is entered, muscle insertions are estimated, the plaque is positioned and suture coordinates on the scleral surface are calculated. In fact, most of the work and decisions involved in eye plaque treatment planning will be performed in this window using this map of the inner surface of the eye.

A retinal diagram is a 2D polar map of the retinal surface, in cartography it is referred to as an azimuthal equidistant projection. All points on such a map are at proportionately correct distances from the center point, and are also at the correct azimuth from the center point. The flag of the United Nations contains an example of a polar azimuthal equidistant projection with the north pole at its center.

Window

The standard Posterior retinal map is centered at the posterior pole of the eye. The radial spokes are meridian lines which extend to the inner limbus. The circles, in expanding order, represent the equator, ora serrata, and the inner limbus. The ciliary body is approximated as occupying the space between the ora and the inner limbus. In Plaque Simulator, the standard retinal diagram is modeled as being an oblate spheroidal surface 1 mm inset from the outer surface of the sclera. By default, the tick marks on the diagram are spaced at 1 mm of arc increments. You may optionally display tick marks using degree spacing. 5 degrees is approximately 1 mm of arc on the inner sclera near the equator of a 25 mm diameter eye.

Standard Posterior Centric Projection with Clock Hour Meridians

PosteriorProjection

Plaque Simulator suture coordinates are a 2D coordinate system on the outer surface of the sclera. A suture coordinate consists of a meridian plane (analogous to earth longitude), expressed as either a clock hour or a toric axis marker angle, and a chord distance along that meridian, measured from the limbus circle. For example, using the default clock hour method, the coordinates of the sutures are at (3:24,12.0 mm) and (4:52,12.0 mm). Using the optional axis marker method, those same coordinates would be expressed as the azimuthal angle and caliper distance pair (168°,12.0 mm) and (124°,12.0 mm). The Retinal Diagram Document preferences can be set to print both a clock hour and an angular version of the diagram (on separate pages) for reference during surgery.

Standard Posterior Centric Projection with Angular Meridians

PosteriorProjectionToric


The alternative Anterior map is centered on the pole of the oblate anterior inner surface of the eye. As in the posterior projection, the inner oblate surface is modeled as being 1 mm inset from the outer surface of the sclera from the posterior pole to the limbus and the curvature is then extrapolated from the inner limbus to the pseudo anterior pole which approximates the center of the pupil opening in the iris.

AnteriorPoleLocation

The radial spokes are meridian lines which extend from the inner limbus to the posterior pole. The circles, in expanding order, represent the inner limbus, ora serrata, equator, macula, fovea and finally the posterior pole, a point in 3D space which distorts to form the outermost circle of this 2D map. The tick marks on the diagram default to a spacing of 1 mm of arc but may optionally be displayed using degree spacing.

The anterior projection should be used when working with iris and ciliary tumors. A limitation of the anterior projection is that you can not overlay a fundus collage or an scanning laser ophthalmoscopy (SLO) picture. You may, however, overlay a picture of the iris. This example illustrates treatment of the entire iris. The target region is modeled as a composite of 4 small tumors.

IrisWith4Tumors

Anterior Centric Projection with Clock Hour Meridians

AnteriorProjection


The Diagram control in the toobar selects between standard and extended posterior maps. The extended posterior retinal map is also centered at the posterior pole of the eye. The radial spokes are meridian lines which extend to the pseudo anterior pole located at the center of the pupil opening in the iris (rather than to the inner limbus as for the standard posterior map).

AnteriorPoleLocation

The circles, in expanding order, represent the equator, ora serrata, the inner limbus, the pupil opening in the iris and the pseudo anterior pole. The pseudo anterior pole is, of course, actually a point in 3D space which distorts to form the outermost circle of this 2D map (this is analogous to the way the northern and southern poles of the earth distort to form the northern and southern rectangular edges of the commonly encountered Mercator cylindrical projection map of the earth). The iris is approximated as occupying the space between the inner limbus and the pupil opening in the iris. The pseudo anterior pole lies at the center of the pupil (aka iris center).

This extended projection is best used when working with anterior and ciliary tumors that extend to the inner limbus so that you can overlay a wide angle SLO picture as well as plot isodose coverage of the tumor base and base-margin (PTV) that extends anteriorly to the inner limbus. Alternatively, you can use the anterior projection for these cases.

Extended Posterior Centric Projection with Clock Hour Meridians

PosteriorProjectionIris
CastroviejoCalipers

Castroviejo caliper

To use the calculated suture eyelet coordinates, clock hour (or angle) meridian and distance, the surgeon first marks the calculated meridian lines on the sclera, either by visually estimating from experience, or using a toric (azimuthal) axis marker. Then, using a Castroviejo caliper, the suture points are marked at the calculated chord distances from the limbus along the clock hour (or anglular) meridian lines.

AxisMarker

Toric axis marker


Toolbar controls

The toolbar buttons near the top of the window select which tumor is currently being edited, cursor function, enable multiple tumors, and select between left and right eye. Just below the toolbar is the window's status line which reports an assortment of information.

Plaque simulator supports up to 4 tumors per plan. Only one of these tumors is "active", or "editable" at any times. In most instances you will simply use tumor #1 for planning, with tumors 2..4 reserved to create complex shapes or to be used as retinal regions of interest.

Toolbar

SelectMatrixBtn
Plaque 1..4 - Selects the plaque (and its associated dose matrix) that is currently "active".

DragTumor
Drag tumor
When enabled, click the cursor on the tumor to drag it on the diagram. The command and control keys rotate the tumor while dragging.
RotateTumor
Rotate tumor
Sets the cursor mode for rotating the active tumor.
DragApex
Drag apex
When enabled, click the cursor on the tumor apex to drag it on the diagram.
DragPlaque
Drag plaque
When enabled, click the cursor within the projected outline of the plaque to drag it on the diagram. While dragging (ie the mouse button remains down), the plaque will initially rotate to keep the eyelets balanced towards the limbus until you press the option key or invoke manual keyboard rotation by pressing either the command (cw) or control (ccw) keys. Once auto-balancing is disabled, it will remain disabled for the duration of the drag.
DragApex
Edit margin
When enabled, the tumor margin becomes editable. The current spherical polygon auto-margin implementation only works properly for tumors with convex perimeters. You can manually drag margin handles to adjust the margin for concave perimeters.
DigitizePOI
Digitize POI
When enabled, the next cursor click on the diagram digitizes a point of interest.
SelectLandmark
Select landmark
Sets the cursor mode for selecting landmarks for some future action.
LoadSlotBtn
Load slot
Sets the cursor mode for loading and unloading of sources into plaque placeholders.

SelectTumorBtn
Tumor 1..4 - Selects the tumor that is currently "active" and editable.

SingleTumor
Single tumor
Sets the window layout to display only the "active" plaque as determined by the plaque button.
MultiTumor
Multiple tumors
Divides the window layout into 4 panes to display all four plaques. The pane of the active plaque is bounded with a thicker black frame.

LeftEye
Left Eye
Selects left eye.
RightEye
Right Eye
Selects the right eye.

LayoutBtn
Layout - Selects between single and four pane display.

LayoutBtn
Diagram - Selects between standard and extended posterior diagrams.

DuplicateTumor
Duplicate Tumor 1..4 - Makes the currently "active" tumor an exact copy of one of the other three tumor models. For example, if tumor #1 is the active tumor, its segment in the 4 part control is disabled and you can elect to make tumor #1 a copy of either tumor #2, #3 or #4. This control will be hidden when the window width is too narrow to allow it to be visible.

LayoutBtn
Calculate 2D Matrices - Convenience button to recalculate all 2D matrices and the dose histogram. Same as clicking Calculate 2D Matrices in either the Dosimetry menu or Dosimetry window toolbar. This control will be hidden when the window width is too narrow to allow it to be visible.

Tumor group

The controls in this group apply to tumor digitization and shape. Buttons with small triangles in the lower right corner also include a contextual menu which lists options for that button's function. Contol-clicking (note: the rightmost button on a multi-button mouse is usually equivalent to a "control-click" in MacOS) on these buttons displays the menu.


TumorGroup
  • Peak - the tumor has a conical peak-like shape.
    PeakBtn
    PhotoMenu
    • Truncated Cone - the tumor is a truncated conic which is clipped at the apex height. The height of the missing conic peak defaults to 20 mm but can be customized in the Custom Shape... sheet.
    • Constant Thickness - the tumor has constant thickness defined by the apex height.
  • Dome - the tumor is domed shaped (default).
  • Mushroom - the tumor is mushroom shaped, the popup menu further refines the shape.
    MushroomBtn
    PhotoMenu
    • Stem - the tumor has a generic mushroom-like shape with a stem.
    • Ball - the tumor has a generic ball or button-like shape.
    • Custom Shape... - opens a dialog sheet that permits more precise customization of the tumor shape.
  • Apex - opens the Tumor Apex modal sheet to enter the tumor height, usually determined from ultrasound images, and set the PTV margin surrounding the base.
  • Std. - opens the Standard Tumor dialog to create a tumor with a circular or elliptical base.
  • Lock - lock the active tumor location.
  • Tumor - begin digitizing the base perimeter of the active tumor.
  • Clear - delete the active tumor perimeter.
  • Shade - tint the tumor perimeter.
  • Photo - map a fundus photo collage onto the diagram, the popup menu adjusts the appearance of the fundus collage.
    PhotoBtn
    PhotoMenu
    • Auto Correct Collage - when enabled, the fundus collage is circumferentially warped to display correctly on the retinal diagram.
    • Transparent Background - makes fundus collage pixels of the selected color (e.g. black or white) transparent when mapped to 2D and 3D surfaces. The color to make transparent is set in the Image Window when calibrating the fundus image.
    • Photo slider - eliminates the fundus photo backgound.
  • Landmark - enables landmark digitization.
    LandMarkBtn
    LandmarkOptionsMenu
    • Select All - Select all landmarks for a subsequent action such as deletion.
    • Deselect all - Deselects all landmarks.
    • Properties... - Opens the landmark properties sheet.
  • Clear Landmark - deletes any currently selected landmark(s).
  • LandMk menu - selects current landmark type.
    LandmarkTypeMenu
    • Artery - Subsequent landmarks are tagged as type artery.
    • Vein - Subsequent landmarks are tagged as type vein.
    • Other - Subsequent landmarks are untyped - useful to mark areal regions.

Plaque group

The controls in this group adjust basic plaque location which is sufficient in most instances. For greater control over plaque location, offset and orientation use the 3D Setup window and its helper windows.


PlaqueGroup
  • Plaque - rotate the active plaque.
  • Lock - lock the active plaque location.
  • Center - center the active plaque on the active tumor and balance the plaque eyelets.

Tools group

The controls in this group apply to diagram appearance and the digitization of retinal landmarks. Buttons with small triangles in the lower right corner also include a contextual menu which lists options for that button's function. Contol-clicking (note: the rightmost button on a multi-button mouse is usually equivalent to a "control-click" in MacOS) on these buttons displays the menu.


ToolsGroup
  • Ruler - displays a distance measuring tool on the diagram. The ruler measures the chord or arc length between any two points on the diagram. The ruler is primarily used to measure tumor size and dosimetric margins around the tumor base. To use the ruler, simply drag the handle at each end to the desired position, or drag the distance indicator at the ruler center.
    RulerBtn
    RulerMenu
    • Properties... - Opens the ruler properties sheet where you can customize ruler properties and enable multiple rulers.
  • RulerProperties
  • Coord. - displays scleral suture coordinates for the eyelets.
    CoordBtn
    EyeletMenu
    • Balancing Eyelets Only - Show coordinates only for the balancing eyelets. A pair of balancing eyelets is used to auto-center and orient the plaque for easiest surgical placement. The balancing eyelets are also (usually) the eyelets that will be used to attach the plaque to the sclera. This is the recommended display setting.
    • All Eyelets - Show coordinates for every suture eyelet.
    • Balance Anteriorly - When dragging, rotate the plaque so that the designated pair of balancing eyelet are equidistant from the limbus in the direction of the anterior pole. This is the default behavior and applies to almost all tumors.
    • Balance Posteriorly - Rotate the plaque so that the designated pair of balancing eyelet are equidistant from the limbus in the direction of the posterior pole. This behavior is useful when positioning a plaque over the cornea in order to treat tumors that extend into the iris. In this rare situation we need to keep the suture eyelets posterior to the limbus while most of the plaque face needs to be anterior to the limbus to cover tumor in the iris.
    • Show Toric Axis Markers - Show toric axis marker settings on the diagram.
    • As Clock Hours - Meridians are expressed as clock hours.
    • As Degrees - Meridians are expressed as toric axis marker degrees.
  • Labels - displays tick marks and other labels on the diagram.
    LabelsBtn
    LabelsMenu
    • Seed Strength - Enable to show seed strength overlays similar to those displayed in the plaque loading window. Useful primarily when loading a plaque with multiple seed strengths. Disabled by default.
    • Slot Index - Enable to show seed slot index overlays. Useful primarily when loading a plaque with multiple seed strengths. Disabled by default.
  • Nerve - projects the myelin sheath surrounding the optic nerve onto the diagram. This is the closest that a plaque and/or its notch can physically be placed adjacent to the disc without pressing on the nerve. PS will alert you to plaque collision with this projection.
  • Macula - outlines the macular region.
  • Muscle - projects muscle insertions onto the diagram. Muscle labels can be disabled in the Diagram Options menu.

Optic Disc group

The controls in this group adjust the location of the optic disc with respect to the geometric posterior pole of the eye.


OpticDiscGroup
  • Elevation - this slider adjusts the elevation angle of the center of the optic disc relative to the geometric axial bisecting plane (aka the 3 o'clock or 9 o'clock meridian plane). This slider covers a range of ±10° in 1° increments. For greater range or finer increments set the elevation in the Eye Size Window. By default, the optic disc is assumed to be centered on the axial bisecting plane. This is usually a sufficient approximation for treatment planning. If CT or MRI based 3D modeling reveals that the nerve is not vertically (ie inf-to-sup) centered on the axial bisecting plane and the precise disc elevation is of dosimetric importance then you may wish to adjust the disc elevation. The aziumthal angle of the disc relative to the geometric posterior pole is usually adjusted when modeling the eye from an axial plane reconstruction in the Image Window.
  • Azimuth - this slider adjusts the azimuth angle between the center of the optic disc and the geometric posterior pole in the axial bisecting. This slider covers a range from 18° to 26° in 0.1° increments. For greater range or finer increments set the azimuth in the Eye Size Window. The default azimuth angle is 21.9°.
  • Sheath Diameter - this slider adjusts the diameter of the sheath surrounding the optic nerve where it connects to the eye. The default diameter is 5 mm, but it is common to encounter diameters up to 6.5 mm. Accurately determining the nerve sheath diameter is important when planning posterior and peripapillary tumors because the sheath presents a physical obstruction to plaque placement which limits how closely the seeds in a plaque can approach the optic disc. Plaques that locate their seeds far from the notch and plaque perimeter can only deliver sufficient dosimetric coverage to the retinal region between the sheath perimeter and disc by prescribing at a great altitude. Eye Physics notched plaques are designed with 7 mm wide notches and locate collimated sources as closely as possible surrounding the notch and usually tangent to the plaque perimeter in order to help compensate for the physical obstruction presented by the nerve sheath. This design enables the Rx point to be at a low altitude if desired and is ideal for intensity modulating the strength of seeds adjacent to the notch and/or plaque perimeter in the manner of a historically classic Patterson-Parker planar implant.

Isodose group

The controls in this group apply to the appearance of isodose maps on the retinal diagram. Buttons with small triangles in the lower right corner also include a contextual menu which lists options for that button's function. Contol-clicking (note: the rightmost button on a multi-button mouse is usually equivalent to a "control-click" in MacOS) on these buttons displays the menu.


IsodoseGroup
  • Matrix - Enables isodose plotting, popup menu selects dose matrix size.
    MatrixBtn
    MatrixMenu
    • 90 X 90 - Low resolution (fastest).
    • 120 X 120 - Medium resolution.
    • 180 X 180 - Standard resolution.
    • 270 X 270 - Better resolution.
    • 360 X 360 - High resolution.
    • 540 X 540 - Higher resolution.
    • 720 X 720 - Maximum resolution (slowest).
  • Lines - Enables isodose lines, popup menu changes labeling properties.
  • Tint - Enables isodose areal tinting, the popup menu adjusts tint opacity.
    TintBtn
    TintSlider
    • Slider - adjusts isodose tinting opacity.
  • Isodose labels spacing slider (S) - Interactively adjusts the location of isodose labels before any shifting required to prevent overlap.
  • Isodose labels clustering slider (C) - Isodose labels on the retinal diagram gravitate towards the posterior pole but are not allowed to overlap. This slider interactively adjusts the allowed proximity between isodose labels.
  • Isodose labels font size slider (F) - Adjusts the font size of isodose labels.

Footer controls
Footer

WndwSize
Opens the Window Size Dialog dialog.

ZoomOut
Zoom out
Reduces the diagram size by a factor of 2.
ZoomIn
Zoom in
Enlarges the diagram by a factor of 2.
ZoomIn
Home
Resets the diagram to its standard settings.

Units
This pop-up menu displays and selects isodose plotting units.
UnitsMenu

PosteriorBtn
Selects the standard posterior pole centered retinal diagram.

AnteriorBtn
Selects the alternative anterior oblate hemispheroid azimuthal equidistant projection.

MMArcBtn
Sets tick mark spacing to 1 mm of arc.

DegreesBtn
Sets tick mark spacing to 5 degrees. (5 degrees is approximately 1 mm of arc on the inner sclera near the equator of a 25 mm diameter eye)

AutoFooterBtn
Enables automatic scaling of diagram line width and label font size as a function of window frame size and zoom magnification.

LabelsSlider
Slider manually adjusts the font size used for diagram labels (this slider becomes active when the auto scaling checkbox is disabled).