Portland Community College | Portland, Oregon

Upon successful completion students should be able to:

1. Effectively perform automated visual field testing in the clinical setting.
2. Skillfully assess and evaluate the visually compromised patient in the clinical setting.
3. Apply the vision screening process to patient intake under the supervision of a qualified ophthalmic technician.

The class will be presented by means of lecture/discussion, audio-visual presentations, handouts and demonstrations. There will be comprehensive lab work requiring demonstrated competency to receive a satisfactory grade. Guest speakers and field trips may be utilized by the instructor as a means of assisting the student in mastering course goals and objectives.

At the beginning of the course, the instructor will detail the methods used to evaluate student progress and the criteria for assigning a course grade. The methods may include one or more of the following tools: examinations, quizzes, homework assignments, research papers, laboratory modules and student participation.

LENSOMETRY

• Demonstrate location of optical center of lens.
• Demonstrate measurement and proper recording of single vision and multifocal spectacles.
• Demonstrate two methods of measurement of spectacles with prism.
• Discuss the significance of vertex distance.
• Demonstrate usage and measure base and power curves of spectacles lenses using the Geneva clock.
• Convert Geneva lens clock measurements into plus cylinder spectacle prescription.

INTRO TO VISUAL FIELDS/AMSLER GRID

• Define the limits of the normal human visual field in degrees from central fixation.
• Define coordinates of the visual field, including radial meridian and circles of eccentricity.
• Discuss the "island of vision" analogy.
• Define "depression, general defect and focal defect" of the visual field.
• Define quadrant, sector, hemi, altitudinal, bitemporal, nasal step, homonymous, congruous, incongruous, ipsilateral and contralateral as they apply to the depressions of the visual field.
• Define "scotoma" and list the 5 criteria for exploring scotoma of the visual field.
• Define "central, pericentral, paracentral, cecal, centro-cecal" as they apply to scotomas of the visual field.
• List the sequence of the visual pathway from the retina to the visual cortex in correct order.
• List the location and dimensions of the normal blind spot.
• Define visual field terminology including: isopters, threshold, suprathreshold, apostilb, decibel.
• Discuss methods of measuring the visual field.
• List and describe visual field screening methods including gross confrontational fields, Amsler grids, FDT.
• Define "footcandle".
• List and describe manual techniques for testing the visual field including tangent screen and Goldmann perimetry.
• Demonstrate calibration of the Goldmann perimeter including both stimulus and background.
• List automated methods for testing the visual field.
• Describe when corrective lenses are required and for which portion of the Goldmann perimetry.
• Describe the process for choosing the appropriate corrective lenses to use for each patient during Goldmann perimetry.
• Distinguish the differences between static and kinetic field testing.
• Differentiate testing strategies for glaucoma and neurological examinations.
• Define minimum criteria for testing an Armaly-Drance glaucoma screening examination including blind spot screening methods.
• Describe the procedure for confirming respect for the horizontal and vertical meridian.
• Describe screening of possible malingering patient with Tangent screen and expected results.
• Demonstrate Amsler grid, confrontation fields, tangent screen and automated (Humphrey) visual fields and show proper documentation.

ESTIMATION OF ANTERIOR CHAMBER DEPTH

• Demonstrate the technique for estimation and grading of anterior chamber depth using both penlight and slit lamp screening methods.
• List the estimation grading scale.

BASIC TONOMETRY

• Discuss the principles and differences between applanation and indentation tonometry and the advantages/disadvantages of each.
• Discuss possible errors in tonometry testing.
• Discuss proper methods of cleaning and list 3 acceptable methods for disinfecting tonometers which contact the eye.
• Discuss technique for each method of tonometry including: non-contact, Tonopen, Schiotz, pneumatonometer, hand-held applanation, Mackay-Marg and Goldmann applanation.
• Demonstrate proper setup of the Goldmann applanation tonometer, including proper positioning of cobalt filter, biprism, magnification, location and illumination of light source.
• Describe the proper endpoint image in Goldmann applanation tonometry.
• Describe interpretation of the measuring dial of a Goldmann applanation tonometer in recording intra-ocular pressure.
• Describe and give the proper abbreviation of the units measured in tonometry.
• Discuss the methods of assessing scleral rigidity.
• Describe the intra-ocular pressure changes during the systole and diastole of the heartbeat.
• Describe the proper rotation of the tonometer prism head for patients with corneal cylinder of more than 3 diopters.
• Demonstrate the process of checking calibration of a Goldmann applanation tonometer in all three measurement ranges.
• Demonstrate checking of calibration of TonoPen and proper measurement technique including replacement of OcuFilm covers.
• Name factors altering intraocular pressure.
• Demonstrate non-contact tonometry and Schiotz tonometry including checking of calibration, cleaning and assembly.
• Describe when additional weights are required in measurement with Schiotz tonometers..
• Describe how central corneal thickness relates to measurement of intraocular pressure readings.
• Describe how intraocular pressure reading are converted for thick or thin corneas.
• List 3 types of patients for whom tonometry should not be performed.

KERATOMETRY

• List 4 applications for keratometry.
• Describe the "average" corneal measurement.
• Demonstrate proper focusing of the eyepiece to assure accuracy.
• Describe method of assuring measurement of corneal apex.
• Describe the reason for rotating the instrument to align horizontal mires.
• Define corneal astigmatism.
• Define "with the rule" , "against the rule" and "oblique" astigmatism.
• Discuss technique, demonstrate measurement and properly record corneal curvature using the keratometer.
• Demonstrate checking calibration of keratometer with calibration balls.
• Convert "K" readings to mm of radius.
• Describe method of grading amount of distortion in corneal mires.
• Describe method of extending the range of keratometer in both the upper and lower ranges of measurement.
• List 4 ways to avoid errors in keratometry.