* Make sure you read the article titled "How To Perform Scleral Indentation" Review Of Optometry November, 1986 by Anthony A. Cavallerano, O.D., Leo Semes, O.D., John Potter, O.D., and Matthew Garston, O.D. Plus the chapter in Dr. Casser's book too.

• Schepen's thimble depressor, open or closed end-------Proper, Topcon, Heine, etc. For stability the thimble type depressors are best held between the thumb and index finger.
• Articulated scleral depressor-------Mira
• Mainster-`S' or Double-ended Flat-------Pencil clip type
• There are others:---(Even)--Q'Tips, Coins, paper clips, Etc.

Scleral indentation is not performed on every patient but is reserved for those cases when more information is needed. Scleral indentation is the procedure of choice any time you need to get a totally different view and perspective of an area of peripheral retina that has a questionable diagnosis. There are a number of conditions that scleral indentation will help decide if the condition should be monitored or referred.

CONDITIONS OR CONCERNS THAT NEED INVESTIGATING

• Peripheral retinal holes or breaks, if fluid is present you will notice white with pressure, breaks will open up in a gapping manner.
• Lattice degeneration with questionable breaks within the area of lattice or outside the area; will make the breaks easier to a evaluate and holes will appear darker and surrounding tissue lighter if there is a edematous cuff.
• Vitreoretinal adhesions or traction-helps give you a better idea of the over-lying vitreous liquefaction.
• White without pressure with areas of possible breaks or normal retina.
• Questionable hemorrhages/holes diagnosis, i. e., hemorrhages will just become elevated with indentation, holes will either gap open, look larger and/or appear darker with a surrounding edematous (white) cuff.
• Questionable areas of possible RD or flat retinoschisis---"Correct indentation is not believed to enlagre retinal holes or cause RD."

THINGS TO AVOID DOING

• Never indent the tarsal plate (on top of the Meibomian glands) a secondary inflammation is possible.
• Never indent too close to the limbus (6-7 mm) behind it; or you will be putting pressure on the ciliary body.
• Do not pinch the depressor against the skin and the orbital rim (bone).
• Do not indent patients who may have had a penetrating ocular or orbital injury.
• Do not indent patients with recent intraocular surgery of less than three or four weeks post-op.
• Be extremely careful with patients who have IOL's and even more so if they are anterior or iris attached IOL's.
• Patients with high intraocular pressures the procedure may be painful.

PROCEDURE

Dr. Casser's book says 7 mm and 14 mm every eye is a little different. The superior temporal retina is probably the easiest to indent using a scleral depressor. Then the temporal retina at (9) O'clock right eye and (3) O'clock left eye using a Q'Tip.

1.) Maximum dilation is of utmost importance, this will greatly improve your ability to see the indented retina. At least i gtt 1% tropicamide and i gtt 2.5% Phenylephrine HCl should be used. As a rule scleral indentation is performed through the lids. However, there are times when you will have to use a anesthetic and place the depressor directly on the sclera. If this is the case be careful on older patients for their scleral vessels are more fragile and hemorrhage easily. If you are going to place the depressor directly on the sclera it needs to be sterilize. Use a 70% isopropyl alcohol swab to clean the depressor. Then, "Very important", rinse it off with saline solution and dry off all moisture with a tissue. You don't want to create a nasty alcohol burn on the conjunctiva. In cases of prolonged scleral indentation a drop of anesthetic plus a drop of Celluvisc® is suggested to keep the eyes from drying and patient from tearing.

 

2.) To indent and see the superior temporal retina have the patient look down and insert the depressor just above the tarsal plate and slide the depressor up along the contour of the globe. Then have the patient look slowly up while you gently allow the depressor to follow the lid while sliding the depressor back farther along the orbit. This will allow the depressor to retract the upper lid so it will stay out of your line of view and the pupil. The equator (Vortex Ampullae) are located 11 to 15 mm from the limbus.

 

3.) Shine your BIO in the pupil and observe the red-orange reflex, at this point you should not be using your condensing lens.

 

4.) Have the patient look in the direction where you have placed the depressor. Apply a light amount of pressure with your depressor, if you are properly aligned along the correct axis with the depressor, you should see a darkening or change in the quality of the red-orange reflex, you may have to turn your light source up for the peripheral retina.

 

5.) Insert your condensing lens and adjust yourself so the light shines into the eye in the direction of the depressor. Hopefully, you should have a fairy full lens of imaged retina.

 

6.) Again apply a light amount of pressure with your depressor, you many not have to apply any pressure since the depressor is taking up space and it will be exerting its own pressure. Pay attention to the lower part of your condensing lens. You should now be seeing in that area an elevated possibly "grayish mound" of the indented retina. If you have accomplished this fete you are now seeing the so called "Mouse under the blanket" phenomena. This area may not have a grayish appearance, but just and elevated area with sharply demarcated edges.

 

7.) If you still do not see the elevated normal or grayish retina, check your alignment again; the BIO and depressor must be in direct alignment. Then carefully move the depressor deeper back on to the orbit and gently move it left to right or forward and backward in small amounts. This slight motion may in itself make the area of indentation more obvious, the "Mouse moving under the blanket". If you see the indented retina and it is not directly under the area you are trying to indent have the patient look slowly in the direct of that area.

To bring the hole into view, without moving the depressor, have the patient look slightly to their right and down a little. This works just the same as with your Super Field or 90 diopter lens and the slit lamp.

8.) When you want to see more peripheral retinal areas you will have to have the patient look father away form you. When you want to examine equatorial areas of the retina have the patient to look toward you. Scleral indentation like any other procedure takes time and practice to master. You may find, in the beginning, the use of a practice egg-eye helpful in understanding and getting the feel for the amount of pressure needed to accomplish the desired minimum pressure. The amount of pressure applied is very close to that used when digitally palpating an eye for intraocular pressures. Scleral indentation is not a procedure that is perform on every patient, but rather another procedure that enables you to make a better more accurate diagnosis.

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