Case Study
Subjective Data
A focused subjective assessment of Fatimah Abdullah revealed the following information.
Vision Difficulty: Had no vision problems until today. Wears eyeglasses for seeing distances and reading. Now having difficulty reading. Reports seeing periodic light flashes and small white spots “floating” in the air. Denies eye pain, itching, or tearing. Past Health History: Extraocular extraction of cataract on right eye with implantation of intraocular lens 2 mo ago. Type 2 diabetes mellitus and hypertension. Medications: Glyburide (DiaBeta), 5 mg/day; metoprolol (Lopressor), 50 mg PO daily. Self-Care History: States she was compliant with postoperative regimen of antibiotic and corticosteroid eyedrops and with office follow-up with eye surgeon. Recovery from surgery was uneventful, and eyedrops were discontinued 2 wk ago. Does not have allergies. Walks in the mall at least 1 km three times a week. No resistance or isotonic exercises. Has had difficulty moving bowels with increased straining. Trying prune juice to help.
Coping Abilities: Afraid she is having a stroke.
Objective Data Physical Examination.
Physical examination of the visual system includes inspecting ocular structures and determining their functional status. Assessment of ocular structures should include examining the ocular adnexa, the external eye, and internal structures. Some structures, such as the retina and blood vessels, must be visualized with the aid of equipment, such as the ophthalmoscope. Physiological functional assessment includes determining the patient's visual acuity and ability to judge closeness and distance; assessing extraocular muscle function; evaluating visual fields; observing pupil function; and measuring intraocular pressure. Assessment of the visual system may include all of the components described in the following material, or it may be as brief as measuring the patient's visual acuity. The nurse assesses what is appropriate and necessary for the specific patient. All of the following assessments are in the nurse's scope of practice, but some necessitate special training. Normal findings of a physical assessment of the visual system are outlined in Table 23-3. Age-related visual changes and differences in assessment findings are listed in Table 23-1. Assessment techniques related to vision are summarized in Table 23-4. Common abnormalities found during assessment are listed in Table 23-5.
*Yellow colour is normal after a diagnostic study necessitating intravenous fluorescein injection
†Most cases of heterochromia occur by chance and are not associated with any other symptoms or problems.
The initial observation of the patient can provide information that will help the nurse focus the assessment. A patient with impaired colour vision may dress in clothing with unusual colour combinations. A patient with diplopia may hold the head in a skewed position in an aempt to see a single image. A patient with a corneal abrasion or photophobia may cover the eyes with the hands or wear dark glasses to try to block out room light. The nurse can make a crude estimate of depth perception by extending a hand for the patient to shake. During the initial observation, the nurse should also observe the overall facial and ophthalmic appearance of the patient. The eyes should be symmetrical and normally positioned on the face. The globes should not have a bulging or sunken appearance.
Assessing Functional Status Visual Acuity
Before the patient receives any care, the nurse should record the patient's visual acuity for medical and legal reasons. To assess distance visual acuity, the patient sits or stands 6 metres (20 feet) from the Snellen chart with the usual correction (glasses or contact lenses) left in place unless they are used solely for reading. The nurse asks the patient to cover the left eye with an eye spoon and to read through the chart to the smallest line of leers that the patient can possibly discern. The nurse notes the smallest line the patient can read with 50% or fewer errors. The nurse then asks the patient to cover the right eye, and the process is repeated. At the left of most rows of the Snellen chart is a fraction (e.g., “20/30”) in which the numerator represents the distance the patient is from the chart and the denominator represents the distance at which a normal eye could see the leers in the row. For example, a patient with a visual acuity of 20/30 sees at 20 feet what the patient with no vision problems would see at 30 feet. The larger the denominator, the worse the visual acuity. If vision is poorer than 20/30, the patient should be referred to an ophthalmologist or optometrist (Jarvis, Browne, MacDonald-Jenkins, et al., 2014). Legal blindness is defined as the best corrected vision in the beer eye of 20/200 or worse. If a patient cannot read leers, the nurse can use an eye chart with pictures, numbers, or symbols, such as the STYCAR graded-balls test, the Sheridan-Gardiner leer-matching test, or the Snellen E chart. To evaluate visual acuity when the patient is unable to see even the largest leers, the nurse holds up a number of fingers in front of the patient at successively closer distances and asks the patient to count them. If the patient cannot count the fingers, the nurse asks the patient to indicate whether he or she can see hand motion or light from a penlight in front of the face. If the patient has a complaint of near vision problems, and for all patients 40 years of age or older, the nurse tests near visual acuity. The patient is instructed to hold a Jaeger chart 35 cm (14 inches) from the eyes. The nurse covers the patient's left eye with an eye spoon, asks the patient to read successively smaller lines of print from the chart, and records the visual acuity corresponding to the smallest line of print that the patient can read comfortably. The procedure is repeated with the right eye covered. A normal result is 14/14. A result of 14/20 means the person can read at 14 inches what someone with normal vision reads at 20 inches. If a screening card is not available, the nurse can assess near vision acuity by asking the patient to read from a newspaper.
Extraocular Muscle Functions. The nurse observes the corneal light reflex to evaluate for weakness or imbalance of the extraocular muscles. In a darkened room, the nurse asks the patient to look straight ahead while a penlight is shone directly on the cornea. The light reflection should be located in the centre of both corneas as the patient faces the light source. To assess eye movement, the nurse should hold a finger or object 25 to 30 cm from the patient's nose. The patient is asked to follow the movement of the object or finger with only his or her eyes through the six cardinal positions of gaze (Figure 23-4). This test can indicate weakness or paralysis in the extraocular muscles or dysfunction in a cranial nerve (oculomotor nerve [CN III], trochlear nerve [CN IV], and abducens nerve [CN VI]).
Pupil Function. To determine pupil function, the nurse inspects the pupils and their reactions to light. Pupil size is noted before reaction to light is checked. Pupils should be equal in size and round and should react briskly to light. With age, pupil size decreases (Jarvis, Browne, MacDonald-Jenkins, et al., 2014). In a small percentage of the population, pupils are unequal in size (anisocoria). Pupils should react to light directly (pupil constricts when a light shines into the eye) and consensually (pupil of one eye constricts when a light shines into opposite eye). Accommodation should also be present: when the patient looks at a distant object 0.6 to 0.9 metres away and then is asked to focus on an object 7 to 8 cm from the nose, the nurse should observe convergence of the patient's eyes and constriction of the pupils. Normal pupil function may be documented as PERRLA (pupils equal, round, reactive to light and accommodation).