Nursing Issues within an Ophthalmic Care Pathway - Essay Example

A Critical Evaluation of Relevant Nursing Issues within an Ophthalmic Care Pathway: For example, Measurement of the Intraocular Pressure (IOP) Introduction This assessment provides the students with an opportunity to demonstrate their specialist knowledge through a critical evaluation of relevant nursing issues within an ophthalmic care pathway. I chose to write about tonometry. Before coming to the nursing issues associated with nursing in an ophthalmic care pathway, it is important to delineate the basic academic concepts associated with tonometry. Tonometry involves measurement of intraocular pressure (IOP). This entity draws its relevance with the disease glaucoma (Gazzard et al., 2003, 720-725). This term covers a group of eye diseases characterised by elevated intraocular pressure, and from that point of view, glaucoma might be defined as a pathological rise in the intraocular pressure sufficient enough to damage vision. This is to distinguish the normal elevation of intraocular pressure seen in otherwise normal individuals. Measurement of intraocular pressure is thus one of the first completely new skills that a new ophthalmic nurse practitioner must master. Therefore, knowledge about it is important. Measurement of the intraocular pressure in a large number of normal subjects reveals a normal distribution extending from pressures of 10-12 mmHg to 25-28mmHg (Rossetti et al., 2008, 1053). The pattern of distribution fits a Gaussian curve, so that the majority of subjects have a pressure of about 16mmHg. For clinical purposes, it is necessary to set an arbitrary upper limit of normal. By and large, the eye can stand low pressures remarkably well, but when the pressure is abnormally high, the circulation of blood through the eye becomes jeopardised and serious damage can ensue. For clinical purposes, an upper level of 21 mmHg is often accepted. Above this level, suspicions are raised and further investigations undertaken. Thus measurement of IOP is a significant initial clinical diagnostic step that determines further course of action in such patients (Collaer, Zeyen, and Caprioli, 2005, 196-200). Many nurses need to practice the skill of this measurement since accuracy is a very important parameter leading to the further steps in the ophthalmic care pathway. Rationale Now, the question is, why I have chosen measurement of intraocular pressure to demonstrate my skill as a new specialist nurse. Glaucoma is second only to cataract as a leading cause of global blindness and is the leading cause of irreversible visual loss, largely due to primary open-angle glaucoma (POAG). In 2002, it was estimated that 161 million individuals worldwide had visual impairment and 37 million were blind. Glaucoma accounted for 12.3% of global blindness, Bilateral blindness from glaucoma is projected to affect 8.4 million individuals worldwide by 2010 and greater than 11 million by 2020. Globally, glaucoma is a significant cause of vision loss that disproportionately affects women and Asians (Cedrone et al., 2008, 3-14). While increased IOP is a strong risk factor for the development of glaucoma, it must be remembered that many people with glaucoma have untreated IOPs of 21 mm Hg or less. Elevated intraocular pressure (IOP) is the most important known risk factor for the development of POAG, and its reduction remains the only clearly proven treatment. Several studies have confirmed that reduction of IOP at any point along the spectrum of disease severity reduces progression (Bowling, Chen, and Salmon, 2005, 1102-1104). The Collaborative Normal Tension Glaucoma Study has revealed that IOP reduction reduces the development of POAG in patients with ocular hypertension and reduces progression in patients with glaucoma despite normal IOP (Anderson, and Normal Tension Glaucoma Study, 2003, 86-90). In the UK, as mentioned by Kroese et al. (2002), glaucoma is, indeed, the second most common cause of blindness as estimated from blindness certification. This accounts for 11.7% of all certifications. In the age group of 40-89 years, the prevalence is 1.2% in the white population of the United Kingdom. This indicates this is a grave problem, and as a specialist nurse, I have responsibilities to pinpoint the glaucoma suspect and follow a patient with established glaucoma, where, although not in all cases, IOP measurement is the first most important nursing clinical skill in the care pathway of these patients (Kroese et al., 2002, 978-980). Added to these, since glaucoma has a genetic predisposition, people with a family history of glaucoma and all people over 40 are needed to be routinely checked for IOP. It is, however, to be remembered that IOP measurement alone should not be given a great weightage, since in normal-pressure glaucoma may progress to retinal and visual field changes even while registering a normal IOP (Drance, 2004, 588-592). It is to be remembered also that false positive rates in this method alone is high, so before interpreting the results and declaring them, I needed to be sure always that it is showing a high IOP, and skills are very important determinants of this pathway. Basic Nursing Pathway Considerations The current treatments for glaucoma focus on lowering IOP. This approach may not be enough, as 25 to 38% of patients may continue to lose visual fields and develop blindness even when IOP has been reduced to the normal range. Hattenhauer and associates' (1998) research has suggested that 27% of glaucoma patients go blind in at least one eye after 20 years or more with the disease. It is well known that the underlying pathology in primary open angle glaucoma (POAG) is the death of retinal ganglion cells, where elevated intraocular pressure may play a significant role (Hattenhauer et al., 1998, 2099-2104). There are other intricacies related to the pathogenesis of this blindness related to retinal degeneration; however, clinically for all practical purposes and as has been indicated by research, clinical detection of glaucoma still depends of elevated intraocular pressure and the therapy target is accomplishment of reduction of the same. There are several risk factors for developing POAG and not every patient has all the known risk factors. While some factors appear to complement each other, there are several that may very well operate independently. It is well accepted that POAG is a disease of the elderly and the risk increases with aging. This high prevalence in older populations may be explained on the basis of prolonged exposure to raised IOP or deteriorating microcirculation of the optic nerve head. Several studies have demonstrated that increased IOP is associated with greater prevalence of POAG and glaucoma-related visual field defects in established POAG patients (Shaikh et al., 2003, 445). This clinical observation is amply supported by experimental studies in primates and experience with treating patients with acute glaucoma. In practice I have seen that patients show great variability in response to elevated IOP. I have mentioned previously not all patients exhibit elevated IOP at all times. The term normal tension or low-tension glaucoma is reserved for patients who never show raised IOP. This does not mean that IOP stays normal at all times in these patients. It may be rising at certain times of the day, and this observation has prompted some to recommend diurnal or serial tonography (Gonzalez-Meijome et al., 2008, 457-462). Doing a serial tonometry is difficult in clinical nursing practice due mainly to workload and patient pressure. To accommodate this property of IOP, what I do is measure IOP at different times of the day on different visits. I prefer Goldmann type applanation tonometry for a standardized testing, and I always make it a point to note the time of the day on the examination chart so a diurnal comparison can be drawn in the future. While measuring, it is also important to remember that IOP is influenced by both physiologic and pathologic factors, and it is always prudent to perform multiple pressure measurements over a period of days or weeks to better assess the patient's pressure status (Fogagnolo et al., 2006, 24-28). While this is feasible in an admitted patient, for a outpatient this is impossible. However, it would also be necessary for me to make these patients feel comfortable while measuring their IOP. Before going into the nursing issues with specialist knowledge in this area and skills, it would be worthwhile to go through the relationship of intraocular pressure as an entity and glaucoma. Glaucoma has been traditionally defined as increased intraocular pressure (IOP) beyond the normal pressure range mentioned above. As many as one-half of patients with open-angle glaucoma have normal IOP. A patient with increased IOP and no evidence of optic nerve damage is called a glaucoma suspect. Elevated IOP is a modifiable risk factor in open-angle glaucoma, but it is not diagnostic of the condition. Angle-closure glaucoma may or may not be associated with elevated IOP, but when it is elevated it occurs in proportion to the degree of angle closure (Levy, 2006, 1253-1254). Principles and Apparatus The measurement of intraocular pressure (IOP) is based on the Imbert-Fick principle. This states that the pressure inside the eyeball would be equal to the force necessary to flatten the surface divided by the area of flattening. In all types of measurement of intraocular pressure, this method is utilised where the instrument to measure it would flatten the cornea, and the IOP is determined by measuring the applanating force and the area flattened. The force necessary to flatten the cornea is converted to millimeters of mercury by multiplying the grams by 10 (Shaw, 2006, 420-460). The gold-standard method of intraocular pressure measurement is Goldmann applanation tonometry. The Goldmann tonometer is supplied as an accessory to the slit-lamp microscope. This works on the following principle, when a fixed flat surface is pressed against a spherical surface, such as the cornea, at the point at which the spherical surface is exactly flattened, the intraocular pressure is equal to the pressure being applied. The applanation head is a small Perspex rod with a flattened end, which is fitted to a moveable arm. The tension applied to the moveable arm can be measured directly from a dial on the side of the instrument. The observer looks through the rod using the microscope of the slit-lamp, and the point at which exact flattening occurs can thus be gauged. For applanation tonometry, the patient is seated at the slit-lamp and not lying down but it is still necessary to instill a drop of local anaesthetic beforehand. Because the measurement of the intraocular pressure is such a basic requirement in any eye clinic, attempts have been made to introduce even more rapid and efficient devices (Shaw, 2006, 420-460). 'Air puff' non-contact tonometer, which uses a pulsed jet of air to deform the corneal apex. This method carries less risk of cross-infection and is useful in mass screening. This is less accurate than Goldmann tonometry but Kumar et al. (2006) found that it was within reasonable limits and an acceptable screening method (Kumar et al., 2006, 666-670). Tonopen is a light portable instrument with an in-built software that automatically self-calibrates after each use and selects the acceptable measurements. It is slightly less accurate than the Goldmann tonometry, although van der Jagt and Jansonius (2005) found that this was within reasonable limits (van der Jagt and Jansonius, 2005, 429-435). In Schitz tonometer, a preset weight is placed on the tonometer, which is then placed on the anaesthetised cornea. The amount that the plunger sinks is measured off the scale and the reading is converted to millimetres of mercury from a conversion table. This can be used only on a recumbent patient. The Perkins tonometer is a hand-held tonometer that is based on the same principle as the Goldmann tonometer. Perhaps the most ingenious to date is the air puff tonometer, which measures the indentation of the cornea in response to a puff of air by a photoelectric method. This air puff tonometer is less accurate than applanation, but it is useful for screening, although abnormal results should be confirmed by Goldmann tonometry (Whitaker Jr, Whitaker, and Dill, 1999, 86-91). Technique of Measurement In our clinic Goldmann tonometer is used to measure IOP. The Goldmann tonometer consists of two main parts, a small Perspex cylinder that is applied to the eye by a lever attached to a coiled spring. The tension is controlled by a calibrated drum at the side of the instrument. It is used together with a slit-lamp. I took good care when handling the tonometer to avoid damage to the spring-loaded device. It is often needed in practice to calibrate the tonometer before each clinic. Sometimes work pressure is so much that it cannot be done in every clinic, so at the very least weekly calibration is necessary to ensure accurate intraocular measurement. Any defective tonometer showing >2 mmHg on calibration is usually sent away for repair. This indicates accuracy in measurement is very important (Kaufmann, Bachmann, and Thiel, 2004, 3118-3121). Method I as the specialist nurse have always followed the method very carefully and accurately. The patient who is a suspect and has been advised an IOP measurement is given a clear and concise explanation of the procedure of IOP measurement so the cooperation is ensured. If any patient is wearing contact lenses, they should be removed, and lidocaine ophthalmic drops are used to anaesthetize the cornea. Spread of infection is an issue, and the use of disposable prisms or prism covers is good practice. Sometimes multi-use prisms are available in the clinic, and according to department guidelines, it is always ensured that they are sterilised appropriately between patients. I would always ensure that sufficient numbers of prisms are available so effective sterilisation is ensured. The prism is placed in the clip at the end of the tonometer arm. I would also support the lever with a finger to minimise damage to the spring lever during the attachment of the prism. Next, I would turn the tonometer calibration arm to 1 so that the arm is exerting a slight forward pressure. The complete tonometer would now be placed on the mounting plate on the viewing arm of the slit-lamp and the slit-lamp magnification will be set to 10X with the blue filter in place. The illuminating arm of the slit lamp will be placed at an angle of 60 degrees to the slit-lamp (Tonnu et al., 2005, 847-850). I would then instruct the patient to look straight ahead, and then the slit-lamp will be advanced until a bright blue hue is seen just before touching the cornea. I would observe very minutely up to this point using the naked eye from the side. Next, looking down the viewing piece of the slit-lamp microscope, the tonometer prism is brought gently into contact with the cornea. At that point in time, through the tonometer, I would be able to see two half circles adjacent to each other. These two half circles are important in that they must be symmetrically placed on the apex of the cornea. To make any fine adjustments, the slit-lamp may need to be pulled slightly away from the cornea, and this is necessary to minimise any corneal epithelial damage. The calibrated wheel is turned until the half-circles just overlap, and when the inside edges of the half circles are just touching, the IOP reading is taken (Schneider and Grehn, 2006, 2-6). Nursing Issues Since there are inaccuracies inherent in all methods of tonometry, it may lead to varying IOP measurements seen in individual patients. For our practice, the mean IOP is 16 mmHg; the arbitrary normal range is 10-21 mmHg. In most ophthalmic care pathways, the patient with a presumptive diagnosis of glaucoma suspect is first subjected to an examination where IOP measurement is the first most important step. If the IOP is measured to be high, the patient is immediately subjected to recheck of IOP with a close followup with evaluation of the risk factors that the patient might have been having, and if the IOP is estimated to be more than 30 mmHg, immediate treatment is begun for IOP reduction. A very careful examination is necessary in each visit to watch for progression, deterioration, and success in treatment. A study by Owen et al. (2006) showed that 29% of eyes with an IOP from 30 to 36 mm Hg showed some degree of measurable damage and 72% of eyes with IOP greater than 36 mm Hg showed damage (Owen et al., 2006, 861-868). Stamper et al (1999) also found similar correlations with 28% of eyes with an IOP greater than 30 mm Hg showing damage (Stamper, Lieberman, and Drake, 1999, 299-316). Pohjanpelto and Palva (1974) reported that 11% of eyes with IOP from 30 to 34 mm Hg and 27% of eyes with IOP 35 to 39 mmHg showed changes consistent with POAG. Based on these studies, most physicians would treat ocular hypertension when the IOP reaches 30 mm Hg or greater consistently. However, for an ophthalmic nurse with practice in this area, the IOP must be evaluated in the clinical context. There is no clearly defined level of safe IOP; some individuals may develop optic nerve damage with an IOP of 12 mmHg while others may not develop damage even with an IOP of 30 mmHg (Pohjanpelto and Palva, 1974, 933-937). Nurses have very important roles to play in the clinic delivering specialist practice eye care in glaucoma in that they can deliver both the verbal and written explanations of glaucoma, since this simple step can ensure compliance. The explanation of the eye test and test of IOP is also similarly important, since with understanding, the patients' anxiety levels may go down, they may become more cooperative during the test, and these may help to change their behaviours to this disease. Although for them, using a Schiotz tonometer is rather an easy procedure to perform, there are now concerns regarding its disinfection procedure. Since these come into contact with the cornea and the tear film, they must be properly disinfected to prevent cross-infection (Chronister, 1997, 164-166). These contact devices have been recommended to be disinfected appropriately before and after use; however, recently it has been found that use of recommended disinfectants may lead to damage of these tonometers leading to error in reading. Pulsair 3000 and Impact Probe rebound tonometer has been used, and it has been found that in the clinical setting, even without use of any local anesthetic, rebound tonometer is well tolerated, takes a little more time to perform, but produces equivalent results (Alward, 1998, 1298-1307). There has always been a concern about the safety of nurse-run IOP measurements and its accuracy. Studies reveal that many elderly patients do not get an appropriate glaucoma checkup. Many patients feel that they would have get their eyes checked earlier, would have started treatment earlier if they would have known or told, and many patients wait for a long period of 18 weeks to get treatment (Wallace et al., 2008, 7-23). Given the frequency of this condition and given the fact that sustained elevated intraocular pressure for such a prolonged period may lead to irreversible damage to the eye and vision, it would be logically coherent that trained nurses take up the job (Duffy, 2000, 88-91). Nurse-run intraocular pressure measurements can be one of the initial assessments of patients with possible glaucoma, and it can prove immensely valuable for the regular review of the stable patients (Nelson, Aspinall, and O'Brien, 1999, 546-552). Referral of these patients with possible glaucoma include actually a wide range of patients, suspects, with advanced disease, ocular hypertensive, and a large number of patients who are normal but has high IOP as an artifact, or optometrist delivered suboptimal visual field test. Those who are normal can be effectively reassured by the nurses, and nurses can recognise those with advanced disease, and thus nurses can play important roles to prioritize the timing of the followup appointment at the clinic with consultant service. In these clinics, immediate treatment for the newly diagnosed patients may be started, so an adjustment can be accomplished at a followup visit, since it is now well known that although high IOP is not central to the diagnosis of glaucoma, it is a treatable risk factor, more so due to the fact that higher IOPs are associated with faster progression of the defects in the visual field (Hume and Abbott, 1995, 34-36). Conclusion Nurses will take more time to measure and IOP, but they have no chance to make an error or cause pain or hurt to the patient due to haste, since with error, doctors will not trust them, and with hurt, pain, or injury, the patients will not trust them. Accuracy and safety are the two most important aspects of nursing assessment of IOP. To be able to accomplish those, a care pathway for glaucoma care where the trained specialist nurse initiates the process of glaucoma care at least as the foremost screening process would be welcome given the critical importance of IOP in diagnosis and management of glaucoma. Technical skills of measurement are important, and this assessment displays the clinical skills that I need to perfect in my day to day practice. Reference List Alward, WLM., (1998). Medical Management of Glaucoma. N. Engl. J. Med.; 339: 1298 - 1307. Anderson, DR. and Normal Tension Glaucoma Study, (2003). Collaborative normal tension glaucoma study. Curr Opin Ophthalmol; 14(2): 86-90. Bowling, B., Chen, SDM., and Salmon, JF., (2005). Outcomes of referrals by community optometrists to a hospital glaucoma service. Br. J. Ophthalmol.; 89: 1102 - 1104. Cedrone, C., Mancino, R., Cerulli, A., Cesareo, M., and Nucci, C., (2008). 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Tonnu, PA., Ho, T., Sharma, K., White, E., Bunce, C., and Garway-Heath, D., (2005). A comparison of four methods of tonometry: method agreement and interobserver variability. Br. J. Ophthalmol.; 89: 847 - 850. van der Jagt LH, Jansonius NM (2005). Three portable tonometers, the TGDc-01, the ICARE and the Tonopen XL, compared with each other and with Goldmann applanation tonometry. Ophthal Physiol Opt 25:429-35. Wallace, EJ., Paterson, H., Miller, S., Sinclair, A., Sanders, R., and Hinds, A., (2008). Patient profile and management in advanced glaucoma. British Journal of Visual Impairment; 26: 7 - 23. Whitaker Jr, R., Whitaker, VB., and Dill, C., (1999). Glaucoma: what the ophthalmic nurse should know. Insight; 24(3): 86-91. Read More