Ординатура / Офтальмология / Английские материалы / Practical Ophthalmology A Manual for the Beginning Ophthalmology Residents 4th edition_Wilson_1996

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Table 9.2 Common Skin Abnormalities and Characteristics

A millimeter ruler is used to measure the intercanthal distances (ie, the distance between the two medial canthi and the distance between the two lateral canthi). The normal distance between the medial canthi (about 30 mm) is nearly one half the interpupillary distance. The distance between the lateral canthi is routinely measured during exophthalmometry (discussed later).

The interpupillary7 distance (IPD, or PD) is the distance between the centers of both pupils. The PD is routinely obtained during spectacle lens fitting using the corneal reflection pupillometer, an optical instrument that measures the distance between the two corneal reflections (assuming orthophoria). In the clinic it is convenient to use a millimeter ruler to measure the distance between either the temporal pupillary border or limbus of one eye and the nasal pupillary border or limbus of the other eye as the patient stares at a distance target (Figure 9.2). The binocular technique is described in Clinical Protocol 9.2.

Chapter 9: External Examination

Figure 9.2 Measuring the interpupillary distance by recording the distance between the two corneal light reflections. IPD can also be measured between the nasal limbus of one eye and the temporal limbus of the other eye.

The average distance PD is about 61 mm, with gender and ethnic differences; the corresponding near PD is about 4 mm less.

Check the position of both globes, first by looking directly at the patient. Look for apparent exophthalmos or enophthalmos by the following technique:

1.Ask the patient to tilt the head forward.

2.Look over the patient's forehead and eyebrows from above, sighting along the plane of the face. The examiner mav need to stand up.

3.Elevate both upper eyelids as the patient maintains primary position.

4.Note the position of the front of each globe in relationship to the other. Record any disparity between the two eyeballs of more than 2 mm.

Measurement of the axial (anteroposterior) position of the globes by exophthalmometry is important to document and follow orbital disease. An exophthalmometer measures the distance from the lateral orbital margin to the corneal apex (Figure 9.3). An average value is 17 mm. Measurements are greater in tall people, in those with a large skull or small orbits, and in some patients with axial mvopia. While absolute values help in following an individual patient, the most important initial measurement is the difference between the two eyes. A difference of more than 2 mm is considered abnormal. The examiner must make sure that the orbital rims" are stable and symmetric, because trauma and facial deformities can affect the measurements. Instructions for performing exophthalmometry appear in Clinical Protocol 9.3.

Orbital masses may not only produce proptosis but also displace the globe vertically or horizontally. The examiner should measure dis-

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Figure 9.3 Exophthalmometer. (Reprinted by permission from Vaughan DG, Asbury T. general Ophthalmology. 10th ed. Stamford, CT: Appleton & Lange; 1983.)

placement of the globe in any direction. Instructions for doing so are in Clinical Protocol 9.4. Pulsation of the globe should also be noted. Frequently, the patient has to be examined in various seated and supine positions to make ocular pulsations apparent.

Eyelids

Evaluate the symmetry and relative position of the eyebrows. Check to see whether there is any compensatory lifting or wrinkling on one side compared with the other. Note the position of the eyelashes relative to the globe, the number or density of the lashes, and their color. Note the position, movement, and symmetry of the eyelids, including the presence of any scars from previous surgery or injury.

Specific abnormalities of the lids and lashes are described, drawn, or photographed for the medical record. Shining a transilluminator through the eyelid can help differentiate a solid from a cystic lid mass. Table 9.3 lists common eyelid abnormalities.

With the eyelids open, the upper eyelid usually hides the top 1.5 mm of the cornea. The lid creases (palpebral sulci) of the upper and lower evelids divide the lid skin into adherent tarsal portions and loosely attached preseptal portions. The lower lid crease (inferior palpebral sulcus) is more evident in the young. The nasojugal and malar folds of the

;lower lid become more prominent with aging. Table 9.4 lists many normal adult values relative to eyelid structure and function.

To assess eyelid closure, ask the patient to blink and then to gently close both eyes. Normal lid movements are necessary for the lacrimal

^pump to draw tears into the puncta, canalicnli, and lacrimal sac. Any

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Table 9.4 Normal Adult Values of Eyelid Structure and Function

Figure 9.4 Method of recording ptosis measurements.

are outlined in Clinical Protocol 9.5. Figure 9.4 illustrates the method of noting the results of these measurements in the medical record. The degree of blepharoptosis is graded as listed in Table 9.5.

Upper eyelid retraction is assessed with the patient's gaze in the primary position by noting where the upper lid margin crosses the globe in relation to the superior limbus. Lid retraction is classified as listed in Table 9.6. Patients with lid retraction may also exhibit lid lag (von Graefe sign), which is a delayed or fluttering lid movement on downward pursuit.

To detect lower lid retraction, first have the patient fixate a target, such as your finger. While you look at the eye you suspect to be affected, have the patient follow your finger as you move it downward until the lower lid margin of the patient's other eye rests at the lower limbus. Observe whether any sclera shows between the lid margin and limbus of the involved eve, an indication of lid retraction.

184 Chapter 9: External Examination

Table 9.5 Method of Grading Degree of Upper Eyelid Blepharoptosis

Table 9.6 Method of Grading Degree of Upper Eyelid Retraction

Lacrimal System

Observe the lacrimal gland by raising the patient's upper lid and instructing the patient to look downward and medially, thereby prolapsing the palpebral lobe. The orbital lobe is sometimes palpable at the superotemporal orbital rim. Observe and note any lacrimal gland masses (see also "Lacrimal System" under "Palpation" later in this chapter).

Observe the lacrimal puncta for apposition to the globe and patency. Look for punctal eversion, stenosis, functional obstruction by redundant conjunctiva, and occlusion. Inspect the area of die lacrimal sac for swelling and erythema. Note whether there is an overflow of tears.

Globe

To examine the entire ocular surface and sclera, hold the eyelids open and ask the patient to look up, down, right, and left. Twirling a cotton applicator at the upper and lower lid creases helps to raise and lower the lids and avoids direct touching of the lids or globe with the fingers. This technique is described in Figure 9.5.

The volume of the tear meniscus should be assessed bv inspection. Indicator paper can be used alter a chemical injury to check the tear pH.

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Figure 9.5 No-touch technique for raising upper eyelid. (A) Apply a cottontipped applicator to skin of upper eyelid at the lid crease as the patient looks down. (B) Twirl the applicator stick between the thumb and forefinger to bunch up the excess lid skin and elevate the upper lid margin, then elevate the lid skin by raising the applicator stick toward the superior orbital rim.

Inspect the bulbar conjunctiva. Note the type and extent of any conjunctival discharge and classify it as watery, serous, mucoid, or . purulent.

The palpebral conjunctiva is first examined inferiorly. Ask the patient to look up while you gently pull the lower lid downward. Evaluate the tarsal conjunctiva, normally about 3-4 mm wide at its central portion, and as much of the remaining lower palpebral conjunctiva as possible. To expose the upper tarsal conjunctiva, evert the upper lid as the patient looks down. Several techniques for lid eversion are presented in Clinical Protocol 9.6. The central upper tarsus is normally 9-10 mm wide, and the overlying tarsal conjunctiva generally is the best place to evaluate conjunctival papillae and follicles. Exposure of the retrotarsal conjunctiva and upper fornix may require the use of an eyelid retractor.

Examine the anterior globe in sufficient ambient lighting. Subtle color changes of the conjunctiva (eg, icterus) and die sclera (eg, agerelated hyaline plaques at the insertion of horizontal rectus muscles) are better seen with the naked eye in natural sunlight than with slit-lamp illumination. One or more intrascleral nerve loops are often present, usually 4 mm from the superior limbus. I

Measurements of the corneal diameter, when needed, are usually obtained with a millimeter ruler, although calipers and gauges give a more accurate reading. The observer must sight exactly perpendicular to the ruler to avoid parallax error. The horizontal corneal diameter is about 10 mm in the newborn and reaches the adult length of 11-12 mm[;•••• bv 2-? \ears ol age. The vertical diameter is more difficult to assess