Wolf / Kirchhof / Reim The Ocular Fundus

From Findings to Diagnosis
1. Auflage 2005
ISBN: 978-3-13-257829-6
Verlag: Thieme
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 248 Seiten, ePub

Learn how to 'read' the optic fundus: What tests are indicated? How do I interpret the findings? What is the next step? This book guides you quickly and confidently from finding to diagnosis. Practice-oriented Organized by presentation Systematic listing of diagnoses for each presentation Sidebars with a brief summary of the signs and symptoms for each diagnosis Quick reference and study guide in one Comprehensive Describes various examination method Covers even rare findings Differential diagnosis Figures to illustrate each diagnosis Notes on appropriate treatment Confidence Learn to take prompt, goal-directed action. Apply various diagnostic options appropriately and economically. Gain confidence in dealing with equivocal findings.

Sebastian Wolf, Bernd Kirchhof, Martin Reim

Zielgruppe

Ärzte

Autoren/Hrsg.

Wolf, Sebastian

Kirchhof, Bernd

Reim, Martin

Fachgebiete

• Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Klinische und Innere Medizin Medizinische Diagnose und Diagnostik
• Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Klinische und Innere Medizin Augenheilkunde, Optometrie

Inhaltsverzeichnis

1 Introduction
2 Examination Methods
History
Functional Tests
Ophthalmoscopy
Objective Imaging Studies and Their Evaluation
Electrophysiologic Studies
Ultrasound Studies
Biopsy
3 Appearance of Retinal and Choroidal Disorders
Retinopathies with Focal or Mottled Lesions
Prominence of the Macula
Proliferation, Scarring, and Holes in the Macula
Depigmented and Pigmented Focal Lesions in the Macula
Macular Dystrophies with Mottled Lesions
Large Areas of Yellowish-White Exudative Retinopathy
Scattered Pigment Changes with Large Areas of Retinal and Choroidal Dystrophy
Peripheral Retinal and Choroidal Lesions
Retinal Detachments
Retinal Tumors
4 Appearance of Vascular Disorders
Ophthalmoscopic Structure of Fundus Vessels
Variants in the Course of the Retinal Vessels
Abnormal Vessels in the Retina
Rarefied and Elongated Vessels
Narrowed Arterioles and Congested Veins
Bleeding, Cotton-Wool Spots, Hard Exudates, and Retinal Edema
Capillary Aneurysms, Hard Exudates, Bleeding, and Neovascularization
Disorders Involving Primarily Retinal Bleeding
Peripheral Neovascularization of the Retina
Perivascular Infiltrates, Vascular Obliteration, and Retinal Bleeding in Inflammatory Vascular Disorders
5 Phenomenology in Diseases of Vitreous Body
Symptoms with Vitreous Opacities and Specific Examinations
Leukocoria
Blood Vessels in the Vitreous Body
Small Opacities in the Vitreous Body
Diffuse Opacities in the Vitreous Body
Large Opacities in the Vitreous Body
6 Appearance of Optic Nerve Disorders
Blurred Appearance, Hyperemia, and Protrusion—Optic Disc Edema
Pale, Often White, Sharply Demarcated Optic Disc—Optic Nerve Atrophy
Excavations of the Optic Nerve
Anomalous Tissue On and Adjacent to the Optic Disc
7 Diseases without Conspicuous Changes of the Fundus
Floaters
Unilateral Visual Impairment in Children—Amblyopia
Acute Visual Impairment with Normal Optic Disc
Color Vision Defects
Incipient Tapetoretinal Degeneration
Congenital Stationary Night Blindness (CSNB)
Night Blindness with Hereditary Deficiency of the Retinol-Binding Protein
Stimulation
Visual Agnosia

Leseproben

2 Examination Methods

History

As with other medical disciplines, every examination begins by obtaining a history. A knowledgeable and experienced physician will glean more information from history data than a beginner. Therefore, every opportunity should be taken for training in history taking and clinical examination. Intensive interaction with the patient invariably brings new insights and develops the examiner's appreciation of complex disorders.

Lines of inquiry in history taking:

• family history

  • systemic disorders, such as heart attack, stroke, rheumatic disease, infections, diabetes mellitus, and other metabolic disorders, age of parents at death, familial or hereditary disorders
  • ophthalmic disorders such as cataract, glaucoma, strabismus, corrective lenses, inflammation, low vision, or blindness

• patient's medical history

  • as above
  • inquire about accidents.

• ophthalmological history

  • as above
  • inquire about injuries
  • current history, have patient describe disorders and complaints in chronological order.

First, the examiner inquires about complaints relating to the eyes. This exchange should be interactive, meaning that the examiner can always use the patient's answers as the basis for more detailed questions. Naturally, the examiner should not deviate from the systematic approach to history taking. The systemic disorders mentioned in the patient's medical history often provide important information about an ophthalmic disorder. Experience has shown that patients initially tend to deny any connection when asked about familial disorders, i.e., hereditary disorders of the eyes. Often only the next consultation or a subsequent one reveals important information regarding the family history, which then enables the examiner to draw a family tree.

Functional Tests

Meticulous functional testing is essential. This should be preceded by inspection of the anterior eye and objective measurement of refraction. Functional tests provide important information about damage to the retina and the visual system, and supplement the morphologic examinations.

Visual Acuity

Near and distant visual acuity should be carefully assessed without and with the best correction. The true visual acuity of the macula can only be determined after the refractive error has been optimally corrected. Retinal visual acuity is a gauge of the optical power of resolution of the macula. It provides important diagnostic information in the presence of central retinal disorders. Serial optotypes, such as reading texts used in evaluating near visual acuity, provide more reliable information about macular function than singular optotypes.

Standards for visual acuity:

• decimal scale 0.05–1.2

• Snellen scale: 5/4–5/50 (meters) or 20/20–20/200 (feet)

  • numerator: distance of optotype in meters or feet, both as logarithmic scales

• logMAR scale (Minimum Angle of Resolution): linear scale suitable for comparison of poor values with visual acuity less than 5 meters. LogMAR = log10 of the minutes of arc (min arc).

Diagnostic signs in visual acuity testing:

• hesitancy in reading: large visual field defect

• skipping individual letters: small central defects

• plus lens phenomenon: macular edema, specifically in central serous chorioretinopathy.

Visual Field

Perimetry determines the photosensitivity of individual points on the retina at any specified location on the fundus. At selected points on the retina, the sensitivity threshold for light stimuli is precisely determined with the aid of automatic computer perimetry testing. Usually, white light is used for the examination. Perimetry with blue and yellow contrasts has diagnostic significance in optic nerve disorders, especially in primary open-angle glaucoma. Data from computerized perimetry can also be statistically analyzed which allows nearly objective evaluation of the clinical course of disorders.

Fig. 2.1 Goldmann visual field. OD = right eye. The fundus is divided into a lattice of angular graduations to precisely localize points on the retina.

In addition to threshold values, the location and extent of individual visual field defects are important for a diagnosis. Visual field defects are often indicative of the nature and location of the lesion, especially in disorders of the optic nerve or visual pathway. Examination with the classic Goldmann perimeter still has an important clinical significance, due in no small part to the fact that the examiner directly perceives patient cooperation.

Visual field testing is required in the following cases:

• glaucoma

• optic nerve disorders

• suspected neuro-ophthalmologic lesions

• dysfunctions that are readily detectable by ophthalmoscopic examination of the fundus

• loss of visual acuity of uncertain etiology.

Color Vision

Pseudoisochromatic plates such as the Ishihara, Velhagen, or Stilling plates are sufficient for the initial clinical examination. The anomaloscope is used to differentiate congenital color vision defects. The Farnsworth tests are often helpful with congenital maculopathies.

Indications for examining color vision:

• hereditary color vision defects

• optic neuritis

• Stargardt disease (red–green)

• cone dystrophy (blue–yellow)

• dominant hereditary optic nerve atrophy (blue–yellow deficiency)

• ethambutol therapy (various color vision defects).

Contrast Sensitivity

Contrast sensitivity deficiencies are examined using checkerboard or striped patterns. Deficiencies are evaluated by psychophysical assessment or by using the pattern visual evoked potentials (VEP) or by electroretinogram (ERG). The examination methods are not standardized and are therefore generally not comparable. Despite this drawback, measurement of contrast sensitivity has already become valuable in diagnosing subtle dysfunctions of the macula and optic nerve.

Fig. 2.2 Diagram of contrast sensitivity. The spatial frequency increases from right to left, meaning the width of the black bars decreases. Their contrast decreases from bottom to top. This creates the curve of the contrast sensitivity function at the upper margin of the image (Körner H. Visuelle Auflösungsgrenzen und Fehlsichtigkeit. Hildesheim, Zürich, New York: Georg Olms Verlag; 1995: 261).

Ophthalmoscopic Technique for Clinical Diagnostic Examination

• optic disc, macula, and vascular structures

  • classic ophthalmoscope
  • +78-diopter lens with slit lamp

• broad overview of vasculature and periphery

  • indirect ophthalmoscope, +20-diopter lens
  • +90-diopter lens with slit lamp

• details with microscopic precision, limited overview

  • three-mirror lens with slit lamp

Ophthalmoscopy

This classic method of examining the fundus remains the decisive diagnostic modality. The pupil should be well dilated to ensure a good image of the fundus.

Pharmacologic mydriasis:

• example of an eye-drop mixture

  • tropicamide 0.5%
  • phenylephrine 5%.

Direct Ophthalmoscopy

Direct ophthalmoscopy is used to evaluate details of the optic disc, fovea centralis, retinal fixation, and retinal vasculature.

Indirect Ophthalmoscopy

Indirect ophthalmoscopy offers a broader overview of the fundus than the direct method, depending on the refractive power of the employed lens. It readily allows examination of the fundus as far as to the periphery. The convenient monocular indirect ophthalmoscope is equally as effective as binocular ophthalmoscopes mounted on a headband or eyeglass frames. The latter types convey a stereoscopic image and the examiner's hands are free. The headset allows the examiner to simultaneously indent the eyeball to better visualize peripheral retinal changes or perform surgical procedures, such as buckling operations. Indirect ophthalmoscopy is also frequently used in the operating room as well as for bedside examinations and inspection of the fundus in children.

Size of the fundus images:

• indirect ophthalmoscopy

  • 14–28-diopter lenses: 20°–40°
  • 5–10 disc diameters
  • 4–6× magnification

• direct ophthalmoscopy

  • 8°, approximately 2 disc diameters
  • 14–16 × magnification.

High Refractive Power Lenses in Conjunction with the Slit Lamp

High refractive power lenses used in conjunction with the slit lamp combine the broad overview of indirect ophthalmoscopy with the high degree of detail of direct ophthalmoscopy.

Contact Optics with Deflecting Mirrors

These are very important for stereoscopic visualization of details of the central fundus at 10–30 × magnification and for biomicroscopic examination of the periphery.

Special Considerations when Examining Infants and Newborns

The pupils of these small patients may be dilated using the same drops as in adults. General anesthesia is...

Über Autor(innen)

Sebastian Wolf, Bernd Kirchhof, Martin Reim