Visual acuity examination

Visual Acuity Examination. Visual acuity is a measurement of sharpness or clarity of vision. It is often... 

Ophthalmic examination reveals normal visual acuity and fields. 

A 65-year-old male complains of losing his vision Retinal examination reveals optic nerve cupping. Peripheral vision loss is observed on visual field tests, and his intraocular pressure is increased. Following treatment with a drug, he has improved visual acuity and decreased intraocular pressure. 

Opaque deposits in the cornea and lens may occur with chronic phenothi-azine treatment, especially with CPZ. Although visual acuity is not usually affected, periodic slit-lamp examinations are recommended with use of long-term phenothiazines. Baseline and periodic slit-lamp examinations are also recommended for quetiapine-treated patients because of cataract development and lenticular changes in animal studies. 

Ocular Effects. Vision was blurred in 15 of the 23 workers examined as a result of intermediate-or chronic-duration inhalation exposures to high blood concentrations (in excess of 2 pg/L) of chlordecone during its production. The effects on vision were characterized by a disruption of ocular motility following a horizontal saccade by rapid random multidirectional eye movements. Visual acuity and smooth eye movements were unaffected (Taylor 1982, 1985). The rapid eye movements were probably due to disturbance of the brain stem. 

Ophthalmic effects Irreversible retinal damage has been observed in some patients who had received long-term or high-dosage 4-aminoquinoline therapy for discoid and SLE or RA. When prolonged therapy is contemplated, perform initial (baseline) and periodic (every 3 months) ophthalmologic examinations (including visual acuity, expert slit-lamp, funduscopic, and visual field tests). 

Visual acuity tests, slit-lamp examinations, funduscopy and audiometry are recommended periodically in patients treated for prolonged periods of time... 

Baseline and periodic ophthalmologic examinations (visual acuity, slit lamp, fun-duscopic, and visual held tests) periodic tests of knee and ankle reflexes to detect muscular weakness... 

Mann 3 examined the records of 84 men described as suffering from "delayed mustard gas keratitis." This group had been treated at the Contact Lenses Clinic at Moorfields, England. The eye injuries were described as "typical mustard gas scars with corneal degeneration." Mann found a low incidence of onset of trouble in the early postwar years, with a sharp rise in 1931 and peaks in 1934 and 1937 (Figure 4-1). Most, 19-23 yr old when gassed, were about 33-37 when the eye trouble peaked. The onset of symptoms was commonly provoked by minor eye injuries and followed by ulcers that tended to recur spontaneously and cause steady diminution in visual acuity. These men were all fitted with contact lenses. About half were able to wear them with improved vision the others varied from partial success to total failure. Even those helped most, however, suffered slow deterioration of visual acuity. 

Atkinson provided details on two of his patients who had suffered mustard poisoning from the vapor both eyes and lungs were affected. He found no decrease in visual acuity (both men being practically perfect in acuity) between prewar and 20-yr-postwar examinations. Both had some corneal haziness, which proved the precursor of progressive deterioration of vision. 

In all these tests, the men were asked to read Snellen chart numbers as soon as possible after opening their eyes. In the chamber test with CS aerosols, an Orthorater (Bausch and Lomb vision tester) was used to measure near and far visual acuity. All the treated eyes were then examined by ultraviolet and slitlamp procedures to detect corneal injury. The results of all three experiments may be summarized as follows There were fairly wide variations in the times... 

The clinical examination of an ocular chemical bum victim includes all the steps of the ophthalmologic examination measurement of visual ACUITY, slit lamp, and evaluation of the ocular tonicity. 

The effect of bilberry on night visual acuity (VA) and night contrast sensitivity (CS) was examined by using a double-blind, placebo-controlled, and... 

The rationale for the court s opinion was that the diagnosis of cataract (a disease ) required dilation of the pupil and that had dilation been performed at the time of the optometrist s examination, the possibility of a retinal detachment could have been ruled out. In finding the optometrist liable, the court imposed a medical standard of care.Therefore a dilated fundus examination should be used whenever best-corrected visual acuity is reduced, and coexisting disease should be considered a possibihty until an examination determines otherwise. Optometrists may be held responsible for the diagnosis of intraocular tumors—even those as rare as malignant melanoma—in symptomatic patients. 

For routine examinations most clinicians dilate patients pupils only after most other examination procedures have been performed. Complete ocular and medical histories, visual acuities, external examination, pupillary examination, refraction, biomicroscopy, tonometry, and other routine evaluations precede instilling the mydriatic (Figure 20-1). This approach ensures that dilation does not interfere with the refraction, assessment of accommodation or binocularity, or any other refractive finding. In addition, the predilation examination procedures allow the clinician to identify any cautions or contraindications to dilation. In most routine cases ophthalmoscopy or fundus biomicroscopy is the only procedure remaining after dilation. After drops have been instilled for dilation, the patient may proceed to the reception area, the dilation room, or the dispensary for spectacle frame selection while the pupils dilate. While the patient s pupils dilate, the practitioner can examine the next scheduled patient. In 20 to 30 minutes, after all procedures except dilation have been performed on the second patient and the mydriatic drops instilled, the first... 

Visual acuity (pinhole) SUt-lamp examination Tonometry... 

Visual acuity (pinhole) SUt-lamp examination ICeratometry (optional) Refraction (optional) Tonometry Dilated fundus examination if vision <20/50 History... 

If high astigmatism, remove suture, if appropriate Check clarity of posterior capsule Similar to 3- to 5-week examination EUstory Visual acuity (best corrected) SUt-lamp examination Tonometry... 

Patients often report that their visual acuity was fairly good after surgery and then slowly decreased, as though the cataract had returned. Decreased visual acuity and glare are common symptoms. Slit-lamp examination with a dilated pupil shows a thickened capsule with a bubblelike appearance or sheet-like haze (Figure 30-11). The cornea, anterior chamber, vitreous, and fundus should be examined to exclude other sources for the symptoms. 

The incidence of optic neuropathy in thyroid eye disease is 5% to 10%. The class 6 patient usually has mild to moderate proptosis and relatively shallow orbits. Thyroid optic neuropathy may be evidenced by papilledema, papillitis, or retrobulbar neuritis and usually is characterized by a painless and gradual loss of visual acuity. Common visual field defects include central scotomas, arcuate or altitudinal defects, paracentral scotomas, or generalized depressions. Thus visual field and optic disc examinations are the best diagnostic tools for early optic neuropathy. Occasionally, vision loss can occur precipitously over 1 or 2 weeks. Other features of optic nerve dysfunction frequently associated with the decreased visual acuity are color vision disturbances, afferent pupillary defects in the less proptotic eye in patients with asymmetric involvement, and prolongation of the pupil cycle time. 

Patients with minimum optic nerve dysfunction (visual acuity of 20/30 [6/9] or better) may be managed by observation alone. However, the tendency for rapid progression demands serial examinations of visual acuity, visual fields, and pupillary testing. 

Because tamoxifen retinopathy can occur at relatively low total doses of drug, it is important to obtain a baseline examination within the first year after therapy is begun. This should include best-corrected visual acuity, visual fields and Amsler grid evaluations, and fundus examination. It is important to monitor symptomatic... 

Baseline examination with visual acuity, central VFs, CV, dilated fundus examination (with photography) is advised. 

Informed consent is critical, as despite regular ophthalmic exams, optic neuropathy can occur at any stage and any dosage and the loss of vision can be irreversible and severe. Baseline examination with visual acuity, VFs,... 

---