1. Ocular Instrumentation Lynn E. Konkel, M.S., CPOT Heart of America – February 2013

2. Overview Identify most commonly used equipment Identify the reason for use Note: there are many different brands of the same type of equipment, all the brands are not depicted in this presentation Recommend maintaining the manuals for all equipment in a central location. The manuals are very helpful for use, calibration, care and servicing of equipment

3. Pretesting Equipment

4. Transilluminator Handle that contains a rechargeable battery Preferred over a penlight Dial control for the brightness of the light Recommended for assessing pupil reflexes Also may be used to provide additional light source when needed Maintain back up light bulb

5. Pinhole Disk Instrument that looks like an occluder but has multiple holes 0.5 to 2mm in diameter. Used to assess whether the reduced visual acuity is due to refractive error or some other condition. If the visual acuity improves with the pinhole then usually expect a refractive error.

6. Maddox Rod A group of either red or colorless parallel glass rods Used to dissociate the eyes, prevent fusion Used to detect or measure amount of heterotropia or heterophoria. Rods held vertically Rods held horizontally

7. Stereopsis plates Color vision plates Ishihara Pseudoisochromatic

8. Keratometer Kera is the root word for cornea; meter is the suffix for measure therefore this is a instrument that measure the corneal curvature. Obtains the curvature in diopters along the area of least and most curvature. Ex: 44.50@175; 45.25@ 85 Available in manual or automated versions Maintain a stock of replacement bulbs

9. Tonometer Tono = pressure, meter again is to measure. This instrument measures the intraocular pressure. Many styles of tonometers, manual and automated versions. Pictured here is the noncontact tonometer = automated, “air puff”. Readings are stated in millimeters of mercury (mmHg) Record time of day Diurnal variation

10. Tonometer cont. Tonopen Maintain supply of tip covers and batteries Use with corneal anesthetic Goldmann Needs no electricity or special supplies to maintain however, needs an operating slit lamp unless using the hand-held model Use with combo drug of corneal anesthetic and fluorescein, brand name = Fluress

11. Visual Field Testing Eye maintains steady fixation and tests the retina for areas of decreased (or absent) vision. Typically used to test area outside the macula (central vision) Compare/contrast visual field testing to visual acuity testing Typically need to use trial lenses when testing the central visual field (lenses removed for area outside the central 30°) Equipment is complicated, keep manual handy.

12. Visual Field Testing - cont. Amsler grid Used when you want to assess the macular area of the retina. Can detect Central scotomas Paracentral scotomas Distortion = metamorphopsia

13. Auto-refractor Instrument used to estimate a refractive error. Automated version of a retinoscope Can be in combination with an auto-keratometer.

14. Examination Room

15. Projector & Slides Projector – used to project letters, characters, shapes on a silver screen Slides Snellen letters Landoldt rings Numbers Tumbling E’s Worth 4-dot Means to isolate lines/letters Filters – red/green

16. Retinoscope Obtains an estimate of the patient’s refractive error without any input needed from the patient (objective measurement) Projects light onto the retina, moving the light back and forth gives the doctor input as to whether the patient has myopia/hyperopia/astigmatism. Use lenses in the phoropter to neutralize the movement of the light.

17. Ophthalmoscope Instrument used to exam the retina. Eyes are typically dilated for wider view. Direct (pictured on left) Uses internal lenses to assist in focus Can magnify 15x Indirect Monocular – greater magnification then direct, not used much today. Binocular – allows for stereoscopic and wider view of the retina, worn on head and used with handheld condensing lens. Image is inverted (upside down and reversed left/right). Very commonly used today especially for patient’s with disease.

18. Ophthalmoscope Binocular indirect

19. Phoropter Used to obtain patient’s correction for refractive error Distant Rx Near Rx Used to measure phoria’s, accommodation, etc. Contains concave, convex, cylindrical lenses along with prisms and various other lenses (Maddox rod for example)

20. Trial Lenses Tray of lenses and accessories Lenses – sphere & cylinder Prisms Occluders Pinhole disk Maddox Rod/red lens Frame Uses: Test refractive error of an eye Let the patient test how a potential Rx will be Used with other instruments such as visual field bowl analyzers

21. Slit Lamp – Biomicroscope Instrument used to examine the external and anterior structures of the eye under magnification. Can have attachments such as: Goldmann tonometer Camera Observation tube Handheld lenses used in conjunction with slit lamp can be used to examine the retina.

22. Slit Lamp “Accessories” Hruby lens – 55 D lens Goniolens – consists of a contact lens and a mirror. Use a corneal anesthetic and a gel (goniogel). Goldmann tonometer

23. Ancillary Testing Instruments

24. Pachymeter Measures the corneal thickness Used to assist in the diagnosis of glaucoma Do thinner corneas mean increase risk of developing glaucoma? Do thinner corneas mean we are underestimating the IOP? Do thicker corneas mean we are overestimating the IOP? Evaluated prior to refractive surgery Need a corneal anesthetic

25. A-scan Ultrasound Biometry Measure the length of the eyeball Used to calculate the power of the lens implant needed for cataract surgery Requires corneal anesthetic Test being replaced by automated instruments such as the IOL Master Noncontact = no anesthetic

26. Fundus Camera Instrument that takes a picture of the patient’s retina. Documents what is seen on ophthalmoscopy. Can center picture on various parts of the retina – disk, macula, periphery Nonmydriatic versus mydriatic

27. Automated optic nerve/retina instruments Heidelberg Retina Tomograph (HRT). Used to assist in the diagnosis and management of glaucoma GDx Nerve Fiber Analyzer Used to assist in diagnosis and management of glaucoma. Ocular Coherence Tomography (OCT). Used to assist in diagnosis of retinal pathology

28. Corneal Topography Advanced analysis of the corneal curvature Measures the cornea’s shape fro apex to the periphery Used to: Treat and monitor patient’s with corneal disease Prior to refractive surgery

29. Lasers Tunable dye lasers Used in the anterior segment Trabeculoplasty Iridoplasty Photodisruptive lasers YAG laser (pictured), used for secondary cataract, iridotomy. Thermal photocoagulation Argon blue-green/argon monochromatic green/krypton red Extensively used to treat diabetic retinopathy, CRVO, retinal holes, retinal detachments Excimer laser Used in phtorefractive keratotomy Ablates a small amount of the corneal stroma to flatten the corneal

30. Optical Dispensary

31. Lensometer

32. Lens gauge/clock Lens thickness gauge

33. Corneal reflex pupilometer PD stick

34. Where to obtain more information on this subject: AOA Paraoptometric Section, Self-Study Course for Paraoptometric Assistants and Technicians, Revised 3rd Edition Butterworth-Heinemann 1997 Stein, Stein, Freeman, The ophthalmic assistant (8 th edition) Mosby 2006 Cassin, Rubin, Dictionary of eye terminology (6 th edition) Traid 2011

35. Questions?