Retinal Detachment - Diagnosis

Detection of primary retinal tear

Primary breaks are considered the main cause of retinal detachment, although there may be secondary breaks. Identifying primary changes is extremely important. They have the following characteristics.

Distribution by quadrants

• About 60% - in the superior temporal quadrant.
• About 15% - in the superonasal quadrant.
• About 15% - in the lower temporal quadrant.
• About 10% - in the lower nasal quadrant.

Thus, the superotemporal quadrant is the most common location of retinal breaks and if they are not detected initially, it must be examined in detail in the future.

In approximately 50% of retinal detachments, multiple tears can be found, most of which are located within 90°.

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Configuration of retinal detachment

Subretinal fluid usually spreads according to the direction of gravity. The configuration of the retinal detachment is limited anatomically (ora serrata and optic disc, as well as the area of the primary retinal break. If the primary break is located above, the subretinal fluid first flows down according to the side of the break, and then rises back. Thus, by analyzing the configuration of the retinal detachment, it is possible to determine the probable location of the primary break.

A flat inferior retinal detachment, in which the subretinal fluid is slightly elevated on the temporal side, indicates a primary rupture in the same half.

A primary tear located at 6 o'clock will result in retinal detachment below with a corresponding fluid level.

In bullous inferior retinal detachment, the primary break is usually localized in the horizontal meridian.

If the primary rupture is located in the superonasal quadrant, subretinal fluid will move toward the optic disc, then upward to the temporal side to the level of the rupture.

Subtotal retinal detachment with the apex superiorly indicates a primary break located peripherally near the superior border of the detachment. If the subretinal fluid crosses the vertical midline superiorly, the primary break will be located at 12 o'clock, the inferior edge of the retinal detachment corresponding to the side of the break.

When a primary rupture is diagnosed, secondary ruptures can be avoided by following the principles of preventive treatment. The configuration of the retinal detachment helps confirm the primary nature of the rupture.

The sectoral appearance of photopsies has no diagnostic value in determining the localization of the rupture. However, the quadrant in which visual field changes are first noted deserves special attention, since it corresponds to the area of origin of the retinal detachment. Thus, if visual field defects are noted in the superonasal quadrant, the primary rupture may be localized in the inferotemporal quadrant.

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Ultrasound diagnostics

B-scan ultrasound is indicated when the media are opacified and an occult retinal break or detachment is suspected. This is especially true when there is recent vitreous hemorrhage that prevents fundus examination. In such cases, ultrasound helps differentiate posterior vitreous detachment from retinal detachment. It can also detect the presence of breaks in flat retinal detachments. Dynamic ultrasound, in which structures are examined while the eye is moving, is useful for assessing vitreous and retinal mobility in eyes with vitreorostinopathy.

Indirect ophthalmoscopy

Indirect ophthalmoscopy uses condenser lenses of varying power. The higher the power, the lower the magnification; the shorter the working distance, the larger the area to be examined. The examination technique is as follows:

1. The pupils of both eyes should be dilated as much as possible.
2. The patient must be absolutely calm.
3. The lens is held at all times with the flat part facing the patient, parallel to his iris.
4. The pink reflex is brought out, then the fundus.
5. If visualization of the fundus is difficult, it is necessary to avoid moving the lens relative to the patient's eye.
6. The patient is asked to move his eyes and head to select the optimal position for examination.

Sclerocompression

Target

Sclerocompression improves visualization of the retinal periphery anterior to the equator and enables dynamic observation.

Technique

1. To examine the ora serrata area at 12 o'clock, the patient is asked to look down. A scleral compressor is placed on the outer surface of the upper eyelid at the edge of the tarsal plate.
2. The patient is then asked to look up, while the compressor is moved to the anterior orbit parallel to the eyeball.
3. The doctor must align his gaze with the lens and the compressor, which he will use to apply gentle pressure. The pressure is determined as a shaft on the fundus. The compressor must be directed along a tangent line relative to the eyeball, since perpendicular pressure is inconvenient.
4. The compressor is moved to examine adjacent areas of the fundus, while the doctor’s gaze, the lens and the compressor must always be located in a straight line.

Retinal map

Technique. In indirect ophthalmoscopy, the image is inverted vertically and laterally, so the upper half of the chart will show the inferior retina. In this case, the inverted position of the chart relative to the patient's eye corresponds to an inverted image of the fundus. For example, a U-shaped break at 11 o'clock in the eye will correspond to 11 o'clock on the chart. The same applies to the area of "lattice" dystrophy between 1 and 2 o'clock.

Color codes

• The boundaries of the retinal detachment are separated, starting from the optic disc in the direction of the periphery.
• The detached retina is shown in blue, the flat one in red.
• The retinal veins are shown in blue, while the arteries are not shown at all.
• Retinal breaks are colored red with a blue outline; the retinal break valve is colored blue.
• Thinning of the retina is marked with a red stroke with a blue outline, “lattice” degeneration is marked with a blue stroke with a blue outline, pigment in the retina is marked with black, exudate in the retina is marked with yellow, and opacities of the vitreous body (including blood) are marked with green.

Inspection with a Goldmann three-mirror lens

The Goldmann three-mirror lens consists of several parts:

1. The central part allows the posterior pole to be seen within 30°.
2. Equatorial mirror (the largest, rectangular in shape), allowing visualization of the area from 30 to the equator.
3. Peripheral mirror (medium in size, square in shape), allowing visualization of the area from the equator to the ora serrata.
4. The gonioscopic mirror (the smallest, dome-shaped) can be used to visualize the extreme periphery of the retina and the pars plana, so it is rightly believed that the smaller the mirror, the more peripheral the area of the retina it displays.

The central part of the mirror displays the actual vertical image of the rear segment. In relation to the three mirrors:

• The mirror should be positioned opposite the area of the retina being examined.
• When viewing the vertical meridian, the image is inverted from top to bottom.
• When viewing the horizontal meridian, the image is rotated in the lateral direction.

Technique

1. The contact lens is applied as in gonioscopy.
2. The light beam should always be at an angle, except when examining the vertical meridian.
3. When examining sectors of the peripheral retina, the axis of the light beam is rotated so that it always hits the right corner of each mirror.
4. To visualize the entire fundus, the lens is rotated 360, first using the equatorial mirror, then the peripheral one.
5. To provide a more peripheral visualization of a given sector, the lens is tilted in the opposite direction, and the patient is asked to look in the same direction. For example, to view the most peripheral zone corresponding to the 12 o'clock meridian (mirror corresponding to 6 o'clock), the lens is tilted downwards, and the patient is asked to look upwards.
6. The vitreous cavity is examined through the central lens using both horizontal and vertical light beams, then the posterior pole is examined.

Indirect slit lamp biomicroscopy

This is a method of using high power lenses (usually +90 D and +78 D) to provide a large area for examination. The lenses are used in a similar way to conventional indirect ophthalmoscopy; the image is inverted in the vertical and lateral directions.

Technique

1. The width of the slit beam should be 1/4 of its full diameter.
2. The illumination angle is adjusted according to the axis of the slit lamp visualization system.
3. The lens is immediately placed in the slit beam area directly in front of the patient's eye.
4. The red reflex is determined, then the microscope is moved back until the fundus is clearly visualized.
5. The fundus of the eye is examined with the slit lamp constantly adjusted in the horizontal and vertical directions and the lens fixed.
6. The beam width can be increased for a wider view.
7. Increasing the lens power is used for more detailed examination.
8. During the examination of the periphery, the patient's gaze should be directed according to the area of visualization, as in indirect ophthalmoscopy.

Interpretation of results

• The vitreous body in young people normally has a uniform consistency and the same density.
• The central part of the vitreous cavity may contain optically empty areas (lacunae). The compaction of the cavity contents may be mistaken for a posterior detachment of the hyaloid membrane (pseudovitreous detachment).
• In eyes with vitreous detachment, a detached hyaloid membrane is identified.
• Weiss ring is a rounded opacity representing glial tissue detached from the edge of the optic disc. It is pathognomonic of vitreous detachment.
• Pigment inclusions (in the form of "tobacco dust") in the anterior vitreous of a patient complaining of sudden flashing lights and blurriness in the eye may be the cause of a retinal tear. In this case, careful examination of the periphery of the retina (especially the upper half) is necessary. The inclusions are macrophages containing destroyed RPE cells.
• Multiple small opacities in the anterior vitreous or retrohyaloid space are a sign of the presence of blood.
• Under conditions of wide field of view, it is possible to examine equatorial retinal breaks.

Differential diagnosis of retinal detachment

Degenerative retinoschisis

Symptoms. Photopsies and floating opacities are not observed, since there is no vitreoretinal traction. The process most often does not extend to the posterior pole, so there are practically no changes in the visual field, and if they are present, they are characterized by absolute scotomas.

Signs

• The retina is raised, convex, smooth, thin and immobile.
• The thin inner leaflet of "schisis" may be mistaken for old atrophic rhegmatogenous retinal detachment. However, in retinoschisis, demarcation lines and secondary cysts are absent in the inner leaflet.
• In eyes with reticular retinoschisis, tears may be in one or two layers.

Choroidal detachment

Symptoms: Photopsies and floaters are not observed, since there is no vitreoretinal traction. Visual field changes occur with extensive choroidal detachments.

Signs

• Intraocular pressure may be very low due to concomitant ciliary body detachment.
• Choroidal detachment appears as a brown, convex, smooth, bullous, relatively immobile, elevated mass.
• The periphery of the retina and the serrated line can be seen without the use of sclerocomirision.
• The elevation does not extend to the posterior pole, since it is limited by strong adhesions between the suprachoroidal membrane and the sclera at the entry of the vortex veins into the scleral canals.

Uveal effusion syndrome

Uveal effusion syndrome is a rare, idiopathic condition characterized by choroidal detachment associated with exudative retinal detachment. Characteristic residual mottling is often observed after resolution of the UVE process.

Uveal effusion may be mistaken for either retinal detachment with complicated choroidal detachment or annular melanoma of the anterior choroid.

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