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INTRODUCTION TO OCULAR HEALTH ASSESSMENT
Ocular health assessment is usually performed at the end of the examination since pillary dilation and the bright illumination required for many of these procedures may alter other test results．By this point in the examination, the examiner should have a clear indication of the patient’s ocular health status．The case history provides many clues about the health of the eyes．Symptoms such as haloes around lights．flashes of light，or eye pain，imply potentially serious problems．The patient may have a medical condition that has associated ocular manifestations, or he may be taking a systemic medication that produces ocular side effects．Many of the entrance tests such as pillary testing，color vision testing，and extraocular motility testing primarily screen for ocular health problems．The patient’s best corrected visual acuity is an excellent indicator of the health of the eye．If visual acuity is 20/20 or better, the macula and optic nerve are functioning well and the media along the visual axis are clear．If it is not 20/20 and functional etiologies have been ruled out, an ocular health problem is the likely cause．
The main route or the core testing portion of the ocular health examination is designed to effectively and efficiently screen for disease or potential problems in each of three major areas：
1.the anterior segment of the eye
2.the posterior segment of the eye
3.the neurological elements of the eyes and the visual system(including screening for glaucoma)．
If the main route uncovers unusual findings or if the patient’s symptoms or case history suggest an ocular health problem，side trips or problem-specific testing are incorporated into the examination(see Figure 5-1)．There are numerous problem-specific tests available, and that number continues to enlarge as new technology and instrumentation become available．It is beyond the scope of this book to include all these techniques．The techniques chosen for inclusion in this text allow the examiner to assess a wide range of common ocular problems without the need for expensive, hightechnology equipment．
The main route suggested in this section is not meant to be rigidly defined．Individual examiners may prefer to modify this portion of the exam based on their own professional judgment or patient population．For instance，an examiner whose patient population is primarily geriatric may include the Amsler grid test in his main route to routinely screen for macular disease．
When contemplating the tests to include in the core examination, it is important to determine whether or not the patient’s eyes will be dilated．Pillary dilation greatly enhances the examiner’s ability to observe certain ocular structures，such as the crystalline lens, the vitreous, and the peripheral retina．Pillary dilation makes possible a number of techniques which are difficult or impossible to perform on the undilated eye．These procedures include binocular indirect ophthalmoscopy，fundus biomicroscopy, and Goldmann 3-mirror lens eva luation．Standards of optometric care have shifted significantly over the past several years, as demonstrated by the changes in state pharmaceutical laws, so it is advisable for all comprehensive ocular examinations to include a dilated fundus eva luation．
When incorporating pillary dilation into the examination，careful consideration must be given to the sequence of testing．The pharmaceutical agents used for dilation affect the accommodative mechanism of the eye．All tests that require accurate focusing must be completed prior to instillation of the dilating drops．Pillary testing must also be completed before dilation, since the pils will be unable to constrict after dilation．Biomicroscopy should be performed to eva luate the integrity of the anterior segment of the eye and the anterior chamber angle depth must be estimated via the van Herick technique to determine if it is safe to dilate．1f the angle depth is less than 1/4:1，gonioscopy should be performed to more accurately assess the angle．Finally，the patient’s intraocular pressure must be measured prior to dilation．All techniques that are enhanced by pillary dilation should be delayed until after dilation occurs ．These include biomicroscopy of the crystalline lens and anterior vitreous, and eva luation of the posterior segment．Figure 5-2 presents a suggested examination sequence for a comprehensive examination when the patient’s pils are to be dilated．
A number of techniques described in this section involve instruments which are placed in direct contact with ocular surfaces or fluids．It is critical that these instruments be disinfected following the guidelines set forth by the Centers for Disease Control (CDC)．It is recommended that instruments be soaked for at least ten minutes in one of the following solutions：3% hydrogen peroxide, 70% ethanol or isopropyl alcohol，or 0.5% sodium hypochlorite(1 to 100 dilution of common household bleach)．The examiner should observe universal health precautions whenever a procedure involves touching a patient：vigorous hand washing with soap and water or a germicidal handwashing solution is appropriate before and after every patient encounter to prevent the spread of infection．
The procedures presented in this chapter are groed according to their primary purpose．Techniques for eva luating the anterior segment of the eye are presented first．Procedures for observing the posterior segment are next．Tests used to assess the neurologic elements of the eye，including screening for glaucoma，are at the end of the chapter． |
