Diagnostic ultrasonography of equine lens and posterior segment abnormalities.

This research study used a method called ocular ultrasonography to identify and diagnose lens and posterior segment abnormalities in horses. It found that cataracts were the most common abnormality, and the method was useful for evaluating the potential for surgical removal as well as for follow-up after surgery.

Background and Methodology

• This study is a retrospective analysis that looked at equine medical records from a period ranging from January 1983 to March 2001. The objective was to define the indications for an ocular procedure called ultrasonography and to provide representative ultrasonographic images of lens and posterior segment abnormalities.
• The researchers included cases where a horse had a lens and/or posterior segment abnormality, and a complete ophthalmic examination and ocular ultrasonography were carried out. In total, they identified 43 cases (involving 64 eyes) out of 112 cases of equine lens and/or posterior segment abnormalities.

Main Findings

• The abnormalities identified by the ultrasonography, in order of decreasing frequency, were: cataracts, vitreal opacities, retinal detachment, lens luxation, endophthalmitis, microphthalmos, choroiditis, lens rupture, lenticonus, buphthalmos, and phthisis bulbi.
• Even in the presence of anterior opacities (cloudy appearance at the front of the eye), ultrasonography enabled diagnoses to be made. This was beneficial both in the case of surgical (pre and postoperative) and non-surgical cases.
• Additional ocular conditions were found in adult horses with cataracts more frequently than in foals with cataracts.

Conclusions and Implications

• Cataracts were the most common lens abnormality identified in the horses that underwent the ocular ultrasound examination. These cataracts were commonly found alongside other ocacKular abnormalities.
• Ultrasonography emerged as a practical and effective method of examining the lens and posterior segment, particularly useful in cases with anterior opacities. In addition to diagnosis, the method also provided invaluable information regarding the potential for surgical removal of the cataracts and formed a critical component of postsurgical follow-up.