Creating THELMA - The Human Eye Learning Model Assistant
2008, Volume 1, Number 1 25 Introduction Teaching the technique of direct ophthalmoscopy can be challenging and frustrating for both student and men-tor. Direct ophthalmoscopy is best practiced with a pa-tient (or peer) who has a dilated pupil and a high degree of patience and resilience. Patients in a university set-ting are inundated with multiple tests and examinations, and a prolonged fundus examination is one of the least favorable. Improving upon previous models developed over the past 30 years, including those created by Colenbrander, Dodaro and Maxwell, and Lippa, The Human Eye Learning Model Assistant (THELMA) was fashioned from a styrofoam wig head, wig stand, and modified practice eye model to teach and test direct ophthalmoscopy skills. In 1972 August Colenbrander, MD described his man-nequin for ophthalmoscopy [1]. Colenbrander believed the light source should be the ophthalmoscope. There-fore, he used 35mm fundus slides with retroflective scotch-light material which served to reflect light at a narrow angle back to its source. This reduced the amount of scatter and allowed the user to practice the manual skill of directing the beam of the ophthalmo-scope through the pupil. The Colenbrander model could be viewed using direct and indirect ophthalmoscopy, and corneal and lens opacities could be simulated. The commercial Colenbrander model is unfortunately no longer available. In 1981, David Miller, MD described a jar model [2]. Glossy prints of eight common retinal abnormalities were fitted inside a two-ounce white jar with two pupillary apertures drilled through the lid. The lamp from the ophthalmoscope was the light source, and a +20D lens was required to view the images.A decade laterPaul Bradley developed a simple model consisting of a styrofoam wig head with a ping pong ball cut in half and painted with five sets of small-font text placed in the center and close to the equator of the globe [3]. Although retinal images were not displayed, students were able to practice angling and focusing their direct ophthalmoscopes to view all sets of text. Building upon the foundations of the Colenbrander slide model, another eye model was developed by Nicholas Dodaro and Donald Maxwell, Jr., MD [4]. This one utilized a diffuser. Light from the ophthalmoscope shined through a small area of the slide and struck the diffuser which then illuminated the entire background surface. Light reflected through the slide allowed the observer to view the entire image on the slide. Without the diffuser, no image on the slide could be seen. Al-Creating THELMA - The Human Eye Learning Model Assistant Kristina Y. Pao 1* , Tara A. Uhler, MD 2 , Edward A. Jaeger, MD 2 1 Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 2 Department of Ophthalmology, Thomas Jefferson University and Wills Eye Institute, Philadelphia, PA * Corresponding Author & e-mail: Kristina.Pao@gmail.com Reprint requests to Tara A. Uhler, MD, Wills Eye Institute, 840 Walnut Street, Suite 800, Philadelphia, PA 19107 Abstract : To create an eye model for teaching medical students and non-ophthalmology residents direct ophthalmoscopy. : A styrofoam wig head was adapted to view 60 degree images of the posterior pole through a modified practice eye model using slides or printed images affixed to interchangeable retinal plugs. : Slide images are clearer and easier to view but are larger than real size and require indirect illumination. Print images are closer to real size and use direct illumination but need better fidelity. : Both slide and print methods are useful teaching aids. THELMA is a funduscopic eye model developed to assist teaching and testing direct ophthalmoscopy skills. Accepted for publication November 25, 2007 Revision received December 7, 2007 2008; 1:25-29 Available on the web at http://www.academic-ophthalmology.com The author(s) have no personal financial interest in any of the prod-ucts or technologies cited herein. Â 2008