How is the optic nerve head evaluated in a glaucoma suspect?

Updated: Jul 27, 2020
  • Author: Robert H Graham, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Answer

The best examination method is a slit lamp combined with a 60-D, 78-D, or 90-D Hruby lens or a posterior pole lens through a dilated pupil, which offers the following benefits: [24, 25]

  • High magnification

  • Stereoscopic view

  • Excellent illumination

  • Special attention to contour and color

The normal vertical cup-to-disc ratio is 0.3. In a normal rim, the inferior portion is thickest, followed by the superior rim. Patients with myopia have larger eyes and larger discs and cups. Assessing optic nerve damage in small optic discs with minimal cupping may be difficult. [26] Large optic discs may appear pathologic when they actually show only physiologic cupping, especially in African Americans.

Signs of early glaucomatous damage can be subtle, as follows: [27]

  • Generalized enlargement of cup

  • Focal notching

  • Superficial splinter hemorrhage

  • Asymmetry of cupping between 2 eyes

  • Nerve fiber layer dropout

  • Asymmetry of neuroretinal rim

  • Focal thinning of neuroretinal rim

  • Acquired change in disc rim appearance

  • Acquired change in retinal nerve fiber layer

  • Nerve fiber layer deficit

  • Thinning of inferior-temporal rim

  • Progressive enlargement of cup

  • Vertical elongation of cup

  • Cupping to rim margin

  • Exposure of lamina cribrosa

  • Peripapillary atrophy

  • Baring of circumlinear vessels

Search for other abnormalities that may account for the visual field defect, as follows:

  • Tilted disc

  • Disc drusen

  • Optic pits

  • Retinal disease

  • Optic atrophy

Document the appearance of the optic nerve head. The preferred technique is baseline stereo disc photographs for future comparison. Detailed description and drawings should be obtained.

Automated techniques are as follows:

  • Scanning lasers: Advantages include accurate, reproducible, and patient comfort (nondilated); a disadvantage is the cost (expensive)

  • Weinreb et al found that baseline confocal scanning laser ophthalmoscopy Glaucoma Progression Scores, either alone or combined with baseline clinical and demographic factors, can be used to predict the development of primary open-angle glaucoma, and are as effective as stereophotographs in ocular hypertensive patients in predicting the development of primary open-angle glaucoma. [28]

  • Polarimetry - Advantages include accurate and reproducible. A disadvantage is the cost (expensive).


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