Clinical Case Challenge: Opthalmology (Dog)
Challenge: The right eye of an 8 year old MC German shepherd presented for an annual recheck of his eyes. The nucleus of the lens is noted to be cloudy bilaterally. The rest of the ocular examination is normal.
- What is the diagnosis?
- What is the prognosis?
Answer: This is “pulverulent” cataract. “Pulvis” is Latin for “dust,” and the term pulverulent describes the dusty appearance of the center of the lens. The tiny opacities are very discrete and crystalline. They are considered a focal, non-progressive, degenerative change of nuclear proteins. These cataracts remain confined to the nucleus without affecting vision. Cortical cataracts are more likely to progress because the disease will involve newly deposited fibers in the lens cortex.
Challenge:: This is the left eye of a 7 year old SF Labrador Retriever.
- What changes are seen in the image?
- What is the pathophysiology?
- What is your recommended treatment plan?
- Mature cataract, posterior synechia at the 3 o’clock position and pigment dispersion in the anterior capsule.
- Inflammation associated with the cataract has caused a chronic uveitis that has resulted in adhesion of the lateral iris to the anterior capsule.
- Medical treatment will only partially address the problem, since the inciting cause of the problem is the cataract. Surgical intervention is the ideal option. However, the risk of complications in this case may be higher than in an ideal candidate. After medical treatment, the synechia may be surgically detached and cataract surgery performed. The degree of post-surgical inflammation is expected to be greater than usual, and the presence of fibrovascular tissue (responsible for the synechia) creates an increased risk for development of glaucoma. However, glaucoma may develop even without surgical treatment. In these cases, clients should thoroughly understand the risks and benefits of surgery.
3. Video 2A
This is a video illustrating retro-illumination and fundic examination in a 7 year old MC Poodle with a history of progressive visual impairment. The vision loss began a few months ago and presents worse at night. The owner has noticed a whitening of the pupil in both eyes. The dog presented with mydriatic pupils and no pupillary light or dazzle reflexes. Intraocular pressures are within the normal range.
- How would you classify and describe the changes affecting the lens?
- What are the changes affecting the ocular fundus?
- What is your diagnosis?
- What prognosis do you give the owner?
- There is an immature cataract with a spoke appearance.
- The fundus is still fairly visible and shows signs of generalized hyper-reflectivity, a severe decrease in normal vascular patterns and a dark, atrophic optic nerve.
- The history and clinical signs are consistent with progressive retinal atrophy (a spoked wheel appearance of the lens is commonly seen in these cases).
- The prognosis for vision is poor; no treatment is available. However, the patient will likely adapt well to his environment and will have a good quality of life.