Wednesday, July 27, 2011

Practicing through the "incision"

When practicing intraocular maneuvers it is important to get the sensation of working through limited space (like the scleral tunnel) where you will be able to execute a limited range of movements with your hand and your forceps
To practice these movements, you may cut out a cup of a quail eggs box, cut off a the bottom (to allow visualization) and a thin rectangle through which the Utrata forceps will get in, and fix it with pins to a styrofoam head or plaque.
You will be able to practice the capsulorrhexis on a grape or tomato, nuclear rotation, IOL insertion, etc.




Saturday, May 28, 2011

The Surgical Microscope

The surgical microscope is one of the devices residents will need to learn to use for ophthalmic surgery.
Operating under the microscope requires visuo-spatial coordination, coordinating the use of both hands at the same time, and using the zoom, focus and X-Y controls of the foot-pedal to have the best field visualization and a neat image in every step of the surgery.
Ophthalmic surgical microscopes come in a variety of models and prices, starting at U$S 6.000. Very economic optical microscopes that may replace the ophthalmic microscope for the wet laboratory (with the exception of the foot-pedal) are those  usually used for working on electronic circuits.
These microscopes cost around U$S 216. We have found them very useful for practicing different steps of surgery (like the capsulorhexis we learned about in the previous post), to learn how to hold instruments appropriately, place stitches, etc.



Focal distance is quite short, so we taped a -8 magnification lens that allows a longer focal distance and working room, as you can see in the images below:


You can buy these microscopes at The Microscope Depot®. (We have no financial interest in this product).



Monday, April 25, 2011

Continuous Curvilinear Capsulorhexis on Grapes

This idea came from Figueira EC et al: The grape: An appropriate model for continuous curvilinear capsulorhexis, J Cataract Refract Surg 2008, 34:1610-1. 
These authors compare the tensile strength of the red globe grape's skin and the tensile strength of the aging human capsule, which are similar; comparatively, the tensile strength of the porcine anterior capsule resembles more to the human infant's capsule.
In the video you will see the procedure performed by one of our residents. The grape's skin is even more fragile than the human's anterior capsule, so you should be very delicate to avoid tearing it off.
Movements with the Utrata forceps are similar to those in live patients: after central perforation and formation of a small triangular flap, follow an imaginary helix centrifugally from the center to the periphery (you may also watch 'Teaching capsulorhexis' at http://icopedia.ophthalmologyblogs.org).



video