Echography in Ocular Pathology

The ultrasound in ophthalmology took an important place, with multifrequency linear probe between 15 to 18 MHz, with higher definition than the old 7 MHz probe. This chapter describes the different types of ultrasound techniques, described the poorly used A-mode echography, and with reference to Color-Doppler ultrasound, and its normal ocular values.

The ultrasound in ophthalmology held an important place, with multi-frequency linear probe being between 12 to 15 MHz, an obviously higher definition than the old 7 MHz probe. This chapter describes the different types of ultrasound techniques, with special reference to Color-Doppler ultrasound, and its normal ocular values.

The ultrasound in anterior segment has a great number of limitations, despite in patients with ocular cataract or with intraocular lens [IOL], has an important place. Furthermore is useful in patients with iris pathologies [iris tumours], or in patients with malignant glaucoma. The most important technique for anterior segment examination with ultrasounds is the ultrasonic biomicroscopy [UBM] technique, based on 35-50 MHz probes. In the next chapter we describe the UBM examination of anterior segment and its application in different pathologies as cornea diseases or glaucoma.

The ultrasound in posterior segment pathologies is the gold standard examination technique in cases of media opacities, when a cataract or vitreous hemorrhage exists. The first technique used to visualize the posterior segment is the echography. The ultrasound examination is fundamental in retina pathologies as retinal detachment in patients with cataracts. Its importance has been increased with the introduction of color Doppler echography which helps us in vasculophaties as arterial or venous occlusions or in patients with diabetic retinopathy. Furthermore, echography is useful in postoperative vitreous-retina patients, to detect new retinal detachments or peripheral new vessels growth in cases of recidivant hemorrhages.

The posterior segment tumors are the most important indication for ultrasound examination. Echography is essential in choroid melanoma diagnosis; there are a lot of signs in echography which permit us to make a differential diagnosis with the other most frequent intraocular tumor, metastases which appeared with similar echographic signs in ultrasound examination. In the present chapter we also explain the characteristics of other tumors, as retinoblastoma or choroid hemangioms.

The Color-Doppler ultrasound introduced a new point of view in all ocular vasculopathies, thus the diabetic retinopathy [DR] can be studied based in the alterations in the ocular flux, currently DR is studied by scanning laser system, but this technique only permit us to view the intra retinal flux changes, but not the changes which succeed in choroid or in retro ocular vessels, which Color-Doppler ultrasound permit us to observe with an easy noninvasive examination. Furthermore the Color- Doppler echography is useful in patients with a decrease of vascular flux due to carotid insufficiency. Other pathologies as intraocular venous occlusions or arterial embolism produce typical signs in Color-Doppler echography. In this chapter we describe the basis of Color-Doppler examination for ocular vessels, the normal values for each vessel [ophthalmic artery or veins, central artery and vein, and for ciliary vessels], and the typical alterations observed in each vascular pathology.

The ultrasound in ocular traumatism is an essential technique of examination. It is the gold standard technique in case of intraocular foreign body. In these patients magnetic resonance is completely avoided, in a possible metallic foreign body. The ocular trauma makes difficult the posterior segment visualization and echography helps us determine retina lesions, as retinal detachment. The echography is essential for determining intraocular foreign body location.

The ultrasound in ophthalmic surgery is essential in the preoperatory stage, when media opacities cause hindrance in the retina examination. When a patient is admitted for intraocular surgery, echography is mandatory to detect possible intraocular diseases as retinal detachment. In postoperative status, the patients need echographies if new media opacities appear as in case of postoperative hemorrhages in a vitrectomy surgery. In these cases the echography visualizes the posterior pole and permits to establish a correct diagnosis and a postoperative therapy.

Ophthalmology in the last decades has seen a great rise in new images techniques. The appearance of fluorescein angiography, optical tomography, etc. Highlight that other image techniques are unnecessary. But in fact in the present years, the ocular echography has become important, and the advances with new probes with higher frequencies, has helped us in a lot of ocular pathologies, as seen in the last chapter. In the present chapter we describe the indications of other image techniques used in medicine, but with poor knowledge in ophthalmology. The authors describe the indications of computer tomography and magnetic resonance, and also define when we use each technique.