Cataract: Fading of the Light
Cataract is generally defined as an opacity or loss of optical uniformity of the crystalline lens. The development of cataract is therefore a continuum, extending from minimal changes of original transparency in the crystalline lens to the extreme stage of total opacity. During the early stages of cataract development there may be no perceptible effect on the patient’s visual function while in the late stage of opacity the patient’s visual function may be reduced to the mere distinction between light and dark.
Cataracts become significant to the patient when they interfere with visual function. There are a variety of techniques and instruments available for the measurement of these various factors. High contrast resolution or acuity is measured according to the standards established by Snellen. Visual acuity often is referred to as “Snellen” acuity. The chart and the letters are named for a 19th-century Dutch ophthalmologist Hermann Snellen (1834–1908) who created them as a test of visual acuity. Visual acuity refers to the clarity or clearness of one’s vision, a measure of how well a person sees. In the past, measurement of Snellen acuity was the only way that visual function was quantitated. Each of the other factors has a variety of different techniques available for its measurement in the evaluation of visual function. In each case there is no single established test. However, many techniques produce valid reproducible and useful measurements. In addition, the factor of ambient light level can be evaluated in its effect on the measurement of each of these aspects of visual function, and for this purpose several devices have been made available which simulate the glare production of intense light directed into the eye, light which is scattered by the developing cataract and may interfere with the patient’s visual function in each category.
Cataract Surgery (Pre-Operative Measure)
Cataract surgery is one of the most common and effective types of surgery performed today. More than a million and a quarter cataract surgeries are performed in the United States every year, and more than 90% of patients report an improvement in their vision after surgery (Given, 2005).
The process of evaluation and care for the patient with visual functional disability begins with awareness by the patient of his or her limitation. It then leads to consultation for the confirmation of diagnosis, the evaluation of prognosis and planning of appropriate therapy. Patients may become aware through self diagnosis, through conversation with family members or friends who have experienced similar visual functional disabilities or perhaps through a public service vision screening program.
Screening programs are of significant public benefit and are very common in seeking the risk factors associated with diabetes, hypertension, amblyopia, glaucoma, carcinoma of the breast, etc. The objective of screening programs is the identification of risk factors in patients who are asymptomatic with the purpose of establishing earlier diagnosis. Visual functional disability may reach an advanced stage in patients who feel entirely asymptomatic. This is the apparent explanation for studies which have shown that a lower incidence of automobile accidents occurs in states where visual screening for driver licensure is carried out relative to those where no such screening is performed (Gray, et. al, 1999).
In most circumstances, cataract surgery is elective. For the patient with gradually developing cataracts, management consists of reassurance, support and education about the cause of visual disability and its prognosis. During the development of nuclear sclerosis, myopia is induced and changes of spectacle lens prescription will often improve visual function. The use of strong bifocals, appropriate lighting, occasional magnification and other visual aids may satisfy the changing vision requirements as a cataract progresses. Therapeutic dilation of the pupil assists the occasional patient to see around central posterior subcapsular cataract, however, it may also increase glare and visual discomfort. The patient will make the elective decision regarding cataract surgical intervention. The decision will be based on full information regarding the correct diagnosis, the prognosis for improvement and a detailed discussion of the potential risks and benefits of the procedure.
However there are contraindications wherein surgery should not be performed under the following circumstances. Since surgery is an elective decision on the part of the patient, or with the consent of the immediate family of the patient in cases that the patient is not mentally sound to decide for herself (Diane McDonald), surgical operation should not be pursued when the patient or the family do not desire to do so. If the use of glasses or visual aids can still provide functional vision satisfactory to the patient’s needs and desires, after a diagnosis with an ophthalmologists, then surgery would be a distant option. The surgeon and the ophthalmologists however could also decide not to pursue surgical procedure if repeated medical diagnosis shows that surgery will not improve visual function. They could also decide not to give surgical intervention to cataract patients if it shows in the medical record of the patient that she is unfit for surgery. It is very important to have a pre-operative diagnosis before committing to surgical intervention.
The majority of patients undergoing cataract surgery are elderly persons, a patient population with a high prevalence of concurrent multiple medical problems such as coronary artery disease, cerebrovascular disease, hypertension, diabetes mellitus, dementia, arrhythmias, chronic obstructive pulmonary disease, alcoholism, thromboembolic disease requiring anticoagulant therapy, and nutrition problems (American College of Eye Surgeons, 2001). Although the data are limited, anticoagulation does not appear to pose a substantial risk for seriously complicating ophthalmic surgery, whereas discontinuing these drugs may impart some increased risk for new thrombotic events in the patient with pre-existing cardiovascular, cerebrovascular, or thromboembolic disease. In addition, patients undergoing cataract surgery commonly have dysfunctional problems of aging, including psychosocial, economic and nutritional difficulties (ACES, 2001). Functional problems and their cause (often multiple and complex such as Alzheimer in the case of Diane McDonald), defined as difficulties that interfere with daily routines, are often unappreciated when conventional histories and physical examinations are done. Preoperative medical examination and appropriate testing should be done in all patients undergoing cataract surgery, whether the surgery is done in the hospital or elsewhere, and regardless of the type of anesthesia to be used. Preoperative medical management should be guided by the patient’s age, the presence of concurrent medical illnesses, the patient’s use of medicine and the patient’s relative proximity to the location where surgery is performed.
The choice of general, local or topical anesthesia may affect visual outcome indirectly, through the effects of nausea, vomiting, coughing or sudden movement during the preoperative period. Many cataract patients are elderly with multiple medical problems, and thus at increased risk for morbidity during a period of general anesthesia. On balance, properly managed local anesthesia is simpler and safer than general anesthesia, especially in patients with significant cardiac or pulmonary problems. Local anesthesia was recommended to Diane since she has history with peripheral vascular disease.
Surgical Operation
Most conservative surgeons agree that simultaneous extraction is appropriate only in unusual circumstances, for example, whenthe surgery requires general anesthesia and repeated generalanesthesia represents a risk to the patient. The principal concernwhich prevents many surgeons adopting simultaneous extractionis the risk of potentially blinding bilateral postoperative infection orendophthalmitis. With Diane McDonald, it was decided that no simultaneous operation would apply. Her surgeon decided to operate her right eye first since it is more seriously infected than her left eye.
Surgery should not be routinely performed in both eyes at the same time because of the potential for bilateral visual impairment and loss of the ability to adjust surgical plans for the second eye that are based on the results of first eye surgery. However, there are occasional circumstances under which bilateral surgery may be indicated, but the potential benefits and risks to the patient should be critically considered and discussed with the patient (Cassels, et. al., 1999). Consideration of the appropriate interval between the first-eye surgery and second-eye surgery is influenced by several factors: the patient’s visual needs, the patient’s preferences, visual acuity or function in the second eye, the medical and refractive stability of the first eye, the need to develop binocular vision and the presence of symptomatic anisometropia as well as logistical concerns of the patient in traveling back and forth to the physician’s office (Talbot & Perkins, 1998). The patient and ophthalmologist should discuss the benefit, risk and timing of second-eye surgery when they have had the opportunity to evaluate the results of surgery on the first eye. This is going to be more complicated with Diane’s case, suffering from Alzheimer, the physicians cannot measure Diane’s progress through self evaluation because of her mental condition.
The dramatic revolution in cataract surgery over the last 15 years has been spearheaded by the adoption of micro-surgical techniques. This includes transition to the extracapsular procedure and the development of safe, effective intraocular lenses, and the placement of the intraocular lens behind the iris. Effective treatment may require extensive additional complicated surgical procedures, e.g., glaucoma surgery, retinal detachment surgery, therapeutic vitrectomy, penetrating keratoplasty, and anterior segment revision. Prompt diagnosis and management of these conditions is a basic tenet of appropriate medical care. In the absence of co-morbid conditions and complications, a postoperative corrected visual acuity in the 20/40 to 20/15 Snellen acuity range is a reasonable expectation (80-90 percent likelihood) for a patient with functional impairment due to cataract (ACES,2001).
The motivation for using small incision techniques in the cataract surgery is enhanced safety coupled with a more rapid rehabilitation following the procedure. The rationale is that the smaller wound promotes less likelihood of wound dehiscence, more rapid healing and reduced postoperative astigmatism. There is now evidence that (1) the use of small incision technique leads to a more rapid functional rehabilitation of the patient; (2) the use of phacoemulsification leads to less induced postoperative astigmatism; (3) specific or overall complication rates associated with small incisions by an experienced surgeon, compared to a large incision extracapsular procedure, are as good or better (Keener, 1990).
Cataract Surgery (Postoperative Measure)
During the past twenty years, improvements in the technology of cataract surgery have greatly changed the postoperative management of the cataract patient. The widespread transition from general to local anesthesia, the earlier visual rehabilitation with intraocular lens implantation, and the trend toward smaller and durable incision designs have resulted in a much earlier return to the activities of daily life. These changes have also reduced the need for direct face to face care by the operating surgeon. However, the postoperative care is the responsibility of the surgeon, personally or through delegation to colleagues. It is important that care be provided to the patient by competent surgeons, who are both aware of and able to manage any and all complications of the cataract procedure. The postoperative patient is ordinarily examined on the first day following surgery, then again during the month following surgery. Additional visits are thereafter scheduled according to the surgeon’s experience and the patient’s needs. However, through the entire convalescent period, immediate and appropriate care must be readily available to the patient at any time of day or night. The surgeon continues to bear this ultimate responsibility.
The operating surgeon has the obligation to provide education and instruction to the patient regarding the following: resumption of activities, protection of the eye, the use of normal medications, the timing and scheduling of normal postoperative visits, the identifying signs and symptoms of possible complications, and detailed instructions for gaining access to emergency care. Since Diane’s suffering from memory loss due to Alzheimer’s, the surgeon and her immediate family or care giver should be instructed in providing instruction to the patient.
Role of Surgical Nurse in Cataract Surgery Patients
In many surgical specialty areas, the current role of the surgical nurse practitioner (NP) continues to expand and evolve. This evolution may include the incorporation of the skills and functions of the Registered Nurse First Assistant (RNFA) into the role of the surgical NP. In 2003, new federal regulations were issued to universities, medical centers, and hospitals that trained resident physicians. These regulations included a mandate that resident physicians, including surgical residents, do not exceed an 80-hour work week. This has led to an increased demand for first assistants during surgical procedures (Zarnitz, 2005).
The American Nurses Association’s (ANA’s) Code of Ethics for Nurses with Interpretive Statements expresses the moral commitment to uphold the goals, values, and distinct ethical obligations of all nurses. Provision four in the Code of Ethics with Interpretive Statements reads: the nurse is responsible and accountable for individual nursing practice and determines the appropriate delegation of tasks consistent with the nurse’s obligation to provide optimum patient care. Accountability with responsibility is one of the foundations of perioperative nursing because perioperative nurses are accountable for patient outcomes during the surgical experience. Accountability is the quality of being answerable. This provision clarifies that perioperative nurses are answerable for their decisions and the outcomes of those decisions. Core activities for perioperative nursing care include assessment, diagnosis, outcome identification, planning, implementation, and evaluation. When these activities are incorporated into daily practice, perioperative nurses are empowered to provide safe and competent care.
Credit:ivythesis.typepad.com
0 comments:
Post a Comment