 My name is Charles Weber, I'll be speaking about the basics of the glaucoma evaluation and the care of the glaucoma patient. In this lecture, we'll go over the glaucoma exam and important points in that exam are measurement of intraocular pressure, gonioscopy, and a detailed evaluation of the optic nerve head. We'll go over quantified characterization of the optic nerve and the various imaging devices and the reporting styles of those devices and then we'll also finish up with going over visual field testing and the common ways to do that. First component of any patient visit is going to be the history asked of that patient. That would include current complaint from the patient, symptoms, onset, duration, severity and location, past ocular, medical and surgical history, medications and allergies, review of systems, assessing their full general health and not just related to their ocular health as well as their social history which includes tobacco, alcohol and other drug use as well as their occupation and hobbies and any family history of both general medical issues as well as ocular health issues. The general exam, in addition to basic components like assessing visual acuity, will include refraction and that's necessary to perform accurate perimetry to assess the patient's field of vision which we'll get to later. It's also necessary to gauge ocular morphology. For example, with a patient that is farsighted or hyperopic, they'll have potentially an association or higher risk of developing angle closure glaucoma and they may have a smaller disc. This might be the opposite in a patient that's myopic with a larger optic disc and more open or more likely to have open angles. The exam also includes assessment of the external adnexe, the patient's pupils with careful attention for any affurent pupillary defect, confrontation visual fields, ocular motility and slit lamp bimacroscopy. Under the slit lamp, paying close attention to the congenitiva, things that would be perhaps more likely to be seen in a glaucoma patient or at least salient points to be observed, any evidence of congenitival hyperemia, episcleryl venous dilation, hypersensitivity, reactions and characteristic changes associated with ocular allergy, including to topical medications. The presence of any previous surgery, including a filtering bleb and when present, assessing its morphology. Assessment of the episclera and sclera, looking at, in particular, or looking for, sentinel vessels that might suggest an intraocular tumor, thinning of the sclera or an area of staphiloma. Final exam, looking for enlargement of the cornea, endothelial abnormalities such as cruchenberg spindle, keratic precipitates, goutte, beaten bronze appearance of the endothelium, an anteriorly displaced Schwabbe's line, central corneal thickness and pochymetry is an also important thing to look at and will also discuss its measurement in future slides. Examination of the anterior chamber includes an estimation of angle width, comparison between the two eyes, presence of any inflammatory cells, red blood cells and any other material within the anterior chamber. Continuing with the slit lamp exam, it includes examination of the iris, looking at heterochromia areas of atrophy, either generally or sectorally, translumination defects of the iris tissue, both peripherally and more centrally, ectropion UVA, core ectopia, iris nevi, nodules, exfoliative material, neovascularization or any evidence of prior trauma, for example, a sphincter tear. Examination of the lens includes special attention to any lens movement, presence of pseudo exfoliation to the lens capsule or subluxation or areas of zonular injury or loss, and then a dilated assessment of the fundus, including assessment of the optic disc, which we'll discuss in greater detail, any evidence of posterior segment pathology including retinal hemorrhages, vitreous hemorrhages, chorotal effusions, masses, inflammatory lesions, retinal vascular occlusions, diabetic retinopathy and retinal detachment. Intraocular pressure measurement, regardless of the device used, it's important to ensure that that device is in good working order and that it's properly calibrated. There's a number of different ways to measure intraocular pressure and number of different devices. The most commonly used device in the United States in an ophthalmologist's office would be the Goldman intraocular pressure tonometer, and that's depicted here. You'll see on the left hand side of the screen what the mire should properly look like, not too thin, not too thick, and aligned. The alignment is discussed or depicted on the right hand image in the leftmost of those diagrams shows high intraocular pressure, or in other words, the tonometer being too low and needing to be adjusted such that a higher IOP is dialed in. The middle diagram shows too low on the intraocular pressure gauge and on the far right is just right. So just the proper amount of overlap with the inner edges of the rings, just touching one another, giving the correct intraocular pressure measurement. Central corneal thickness and corneal pochimetry is also important in assessment of the glaucoma patient. We know this primarily from the ocular hypertension treatment study, which showed that a thinner cornea conferred a higher risk of glaucoma. The corneal thickness is thought to be more of a biomarker for structural or physical factors involved in the pathogenesis primary opening glaucoma, and is more than simply just an adjustment that's made to intraocular pressure. The figure taken from the OATS data depicted on the right hand side of the screen shows in the far upper left when the risk is assessed by the height of the columns. We can see that with a thinner central corneal thickness and a higher intraocular pressure, there is a higher risk of ultimately developing glaucoma, and those patients followed in the OATS study. As we move to the right in the diagram in each of those rows, there is a reduction in overall prevalence of developing glaucoma as we increase in central corneal thickness. Gonioscopy is also important in the assessment of the glaucoma patient. It's an essential diagnostic tool and examination technique. It's required to visualize the anterior chamber angle due to total internal refraction at the tear-air interface, and depending on the lens used for visualization, we can either observe it directly or indirectly. Depicted in the image on the right hand side of the screen is an indirect view of the anterior chamber angle with a mirrored lens on the surface of the cornea. Direct gonioscopy examples of these lenses are Kepe, Barkhand, Worst, Swan Jacobs, and Richardson. The lens is placed on the surface of the eye, and sealing solution or some other coupling solution is used to fill the space between the gonioscopy lens and the cornea. It gives an erect view of the angle structures and is really mostly used and essential to angle surgery. On the right hand side of the screen, you'll see an example of direct gonioscopy where the goniolens allows us to overcome the total internal refraction for direct observation of the anterior chamber angle. Indirect gonioscopy is more frequently used in clinical examination. It gives an inverted and slightly foreshortened image of the regular mesh work and angle structures. There are two main groups of lenses used in indirect gonioscopy, either flanged or non-flanged. The flanged or goldman type lens requires a coupling gel or viscous fluid. It gives the clearest view, but if there's any pressure applied to the cornea, it can give a distorted anterior chamber angle view and can narrow it artificially. A non-flanged goniolens such as Pozner, Sussman, Zeiss, they give a smaller area of contact which allows for dynamic or indentation gonioscopy and it's coupled merely by the patient's tear film and doesn't require any additional coupling agent. Important points with gonioscopy are first, orienting yourself and recognizing the important angle landmarks. Scleral spur and Schwabbe's line are the most consistent of the landmarks and an easy way to identify Schwabbe's line is with the corneal light wedge which is depicted here in the right hand image. As the two parallel light beams converge, they converge at the peripheral cornea corresponding to Schwabbe's line. This serves as a point of orientation for then going on to identify the other angle structures. Postural to Schwabbe's line is the non-pigmented trabecular mesh work followed by the pigmented trabecular mesh work, the scleral spur and then finally the ciliary body and iris root insertion. It's important also to evaluate for any pathology that's present such as evidence of previous trauma with angle recession, areas of urethral dialysis, peripheral anterior sinecchiae and any other important findings such as neovascularization. There are a variety of different gonioscopy grading systems. The two most common are the Schaefer system and the Spath system. This slide depicts the Schaefer system which describes the angle between the trabecular mesh work and the iris. A grade four angle is a 45 degree insertion of the iris in the angle it forms with the trabecular mesh work. Grade zero is closed angle and then the different grades in between correspond to varying degrees of iris insertion. Spath grading provides greater detail and goes on to describe the peripheral iris contour insertion of the iris root and effects of dynamic gonioscopy. The Spath grading is typically presented in a way that gives a letter as the first capital letter as the first item, a number corresponding to the angle of approach of the iris to the angle structures, a lowercase letter that describes the peripheral iris and then a grade of trabecular mesh work pigmentation. The iris insertion A stands for anterior to Schwab's line, B stands for between the Schwab's line and the scleral spur, C indicates that the scleral spur is visible, D indicates that the deep sclerary body is visible, and E stands for extremely deep with a greater than expected amount of sclerary body visible. Their approach comes with experience to grade this degree of angle and is noted second. Peripheral iris there can be a few different ways to describe its insertion, regular or flat indicating essentially normal presence of iris insertion can be steep or bowed anteriorly or there may be evidence of plateau iris and queer or concave indicates a backward bowing. The trabecular mesh work pigmentation, the assessment of this also comes with experience and frequent viewing of the trabecular mesh work, zero is no pigment going up to grade four which is very intense or broadly distributed pigmentation. The optic nerve exam can be performed clinically in three different ways either with a direct ophthalmoscope, an indirect ophthalmoscope or a silt lamp bio microscope using a posterior pole lens. The direct ophthalmoscope does not provide sufficient detail to detect subtle changes over time, can be useful in screening for glaucomatis optic atrophy but due to its non-depth of detail it does not provide an excellent way to provide assessment in time. The indirect ophthalmoscope can be used to observe cupping and pallor but they're less pronounced in that method and the magnification is inadequate so it's not generally recommended for assessment of the glaucoma patients and the optic nerve head in particular. Silt lamp bio microscope using a posterior pole lens is the best method for examination for the diagnosis of glaucoma. It gives a binocular view and excellent detail and magnification. The cup to disc ratio alone when noting the optic nerve appearance is not adequate. Early changes that can indicate glaucomatis optic neuropathy would include generalized enlargement of the cup, focal enlargement of the cup, vertical elongation of the cup, presence of a disc hemorrhage, an area of nerve fiber layer loss, asymmetry of cupping and beta zone peripapillary atrophy and we'll show some examples of each of those. A general rule is the isn't rule in assessment of the optic nerve which is meant to indicate that the inferior rim is typically the thickest followed by the superior rim followed by the nasal rim and the thinnest portion of the neuro fiber rim is the temporal rim. This is an excellent example of a normal disc. We see a robust retinal nerve fiber layer. The isn't rule is followed. There's no peripapillary atrophy and there's no disc hemorrhage. This is a large normal disc which does have an increased cup to disc ratio but is otherwise healthy. There's a robust nerve fiber layer. It follows the isn't rule. There's no peripapillary atrophy and there's no disc hemorrhage. This shows a disc hemorrhage with a corresponding RFL wedge defect in area of focal thinning. We can see an inferior temporal notch to the neuro fiber rim. There's a corresponding wedge defect in loss of nerve fiber layer in the same area as the disc hemorrhage. Here we see an example of beta zone peripapillary atrophy with notching and there's also alpha zone peripapillary atrophy present as well which is essentially normal. The alpha zone is the temporal zone depicted here. The beta zone is area of peripapillary atrophy is inferior to the nerve fear where there's an arrow depicting the area of notch. There are a few different ways in which we can quantitatively measure the RFL and there's a few different imaging devices to do that. One of which is the confocal scanning laser tomograph. The other is scanning laser polymetry and a third and more most commonly used type in the United States is optical coherence tomography. We'll take a look at each of those. Confocal scanning laser tomography, the most widely available platform for this is the Heidelberg retinal tomograph. There are serial images that are acquired in planar views and those are stacked upon one another after being aligned to give a 3D morphology of the disc and that's what these images are depicting. Any images of unacceptable quality are automatically eliminated by the device. The output looks like this. At the very top of the output in the area with the capital A next to it gives the quality parameters as well as the patient's identification information. The next section below that shows the image of the disc and nerve fiber layer. C shows more fields analysis of the disc morphology and alerts the examiner to areas of possible difference from the normative database and its own internal regression analysis within the software. The RFL contour is depicted at the bottom portion of the output showing any areas of concern as well. Scanning laser polymetry or GDX takes advantage of the fact that there is a difference in the way in which polarized light is reflected by the nerve fiber layer due to its birefringence and can detect areas of nerve fiber layer damage as a result. The GDX output looks somewhat similar to the Heidelberg as well as the OCT output again showing identification information at the top of the output. There is a section showing essentially an ANFOS or fundus image of the disc at the top portion. Finally it shows summary parameters of the RFL showing areas of the birefringence and detection of possible areas of thinning and then this is used to produce an outline of the RFL as well as highlight areas that are substantially different from the normative database. The most widely used imaging technology in the United States for quantitative assessment of the optic nerve and retinal or fiber layer is optical coherence tomography and there's two main groups of this technology. Time domain is the older device which takes longer to acquire its scans and has less detail. Spectral domain uses a spectral interferogram and Fourier transform to essentially acquire more imaging in less time and in greater detail and so gives us a bit more information about the health of the retinal or fiber layer and greater ability to assess change in time. So again time domain OCT slow and relatively inefficient spectral domain OCT fast in higher resolution. The imaging of the optic nerve fed in RFL the output looks similar to this where we see both a vertical and transverse slice through the optic nerve head as well as a created on FOSS image and highlighted areas of possible change from the normative database. Identification information has been eliminated from the top portion of this output as well as the quality parameters have been cut off by this particular example. At the top portion shows various characteristics of the patient's optic disc, its size, the primary area and the average RFL thickness to give a general overview. Detailed sections are depicted in the bottom portion of the output with green representing average or normal thickness of the RFL in areas of yellow or red falling outside of what's considered the normal range. For each of these devices when the imaging report is evaluated it's important to look at the proper patient is identified that you're looking at the output that corresponds to that particular patient that the correct age and date of birth has been placed into the imaging device for proper comparison to the normative database that the scan has sufficient signal strength to give sufficient quality that it's well centered and aligned. If these are not met the output data may be insufficient to make a quality of assessment of the patient's optic nerve and RFL. Moving on to the visual field, so the overall goal of glaucoma management is preservation of the patient's functional vision and quality of life and the most important assessment of that is the visual field. This diagram depicts the hill of vision with greater detail of vision occurring at the fovea which is the point of fixation at the top of the hill and then decreasing detail as we move out in the field of vision and we're trying to do our best to maintain the entirety of this field of vision for each of our patients. The main purposes of perimetry are to identify anyone with an abnormal visual field and then to also provide a quantitative assessment of that patient's visual field whether normal or abnormal and following that over time. There are two major types, automated static perimetry, this would be frequency doubling technology, a Humphrey visual field for example and then manual kinetic and static perimetry using a Goldman type bull perimeter. I'll discuss mostly the Humphrey visual field testing which is the most widely used type in the United States. There are multiple different testing algorithms available on this device. The different algorithms provide pros and cons to each of them. In general the 30-2 is considered too time consuming to do on a regular basis for patients. It suffers from patient fatigue and may have more variability as a result. The 24-2 algorithm is my preferred approach. There are two types that are possible to use for that, CEDA FAST and the CEDA standard. The FAST is adequate for screening but it doesn't tend to do as well in detecting areas of change or mild loss. FAST can be useful in glaucoma suspects when you're generally searching for an area of scatoma in a glaucoma patient or someone suspicious for glaucoma or in someone that just simply cannot sit for a full standard test. The standard is truly best when used in a confirmed glaucoma patient in detecting progression over time as it provides greater detail. The FAST PAC size 5 is available for patients with low visual acuity providing a larger stimulus but still allows us to detect any scatomas due to glaucoma. The 10-2 algorithm is useful in advanced glaucoma when the peripheral vision is sufficiently changed that a 24-2 or wider field may be of insufficient detail of the remaining vision and it's also useful for macular pathologies. The interpretation of the visual field is important similar to the imaging devices to confirm that the proper patient is being examined, that their age has been input appropriately and that you're looking at the proper date of test. Check the testing algorithm, make sure that you're comparing apples to apples that if the patient had a 24-2 CETA standard in the past that that's what you're comparing to that particular exam day. Confirm that there's an appropriately sized target for the patient's visual acuity. Due to the pupil diameter and refraction both of which can affect the quality of the test. Look at the reliability parameters including the fixation losses, false positives and false negatives and then move on finally to looking at the actual output from the visual field test and evaluate the numerical values of each of the different tests. Be mostly at the pattern deviation for glaucoma's field loss. In the assessment of progression it's important to separate real change from ordinary variation. There's some variability in a particular patient from test day to test day and not every visual field is going to look identical in time even if their glaucoma has been stable. Find the likelihood that change has taken place and that that change is related to glaucoma. Run progression algorithms when you're able to. So if a patient has at least two baseline visual fields and the Humphrey visual field test subsequent tests can then be used to run the progression algorithms and allow the computer's automated software to make an assessment of progression. Take the exam with optic nerve imaging and with the patient's optic nerve head examination. It should fit if there's progression on visual field that there is also progression on their optic nerve head analysis as well as on your examination of the patient. So in conclusion really overall is the attention to detail is paramount. The clinical examination will allow for the most accurate diagnosis of the glaucoma and the glaucoma subtype and then that will further allow you to risk stratify that patient for possibility of future progression or change in time. Testing characterizes the degree of change that's taken place for that particular patient and then subsequent testing allows for detection of advancing glaucoma's change in visual field loss which is of course important to maintaining that patient's functional vision and quality of life.