Corneal endothelial dystrophy

26 Corneal endothelial dystrophy




INITIAL PRESENTATION


Abnormal appearance – cloudy



PRESENTING SIGNS


This condition is usually encountered in dogs and is very rare indeed in cats. The dog is presented with the complaint of cloudy eyes. The owner often thinks that it is developing cataracts. Normally both eyes are affected but to differing degrees – the owner might only be concerned about one eye. The dog is likely to be comfortable with no or minimal conjunctival hyperaemia – the owner is probably not worried about the eyes looking red. However, sometimes the owner feels that the eyes are bulging (see Clinical examination). Vision is usually normal or only minimally impaired – it is the change in appearance of the eyes which concerns the owner. The condition is normally insidious in onset and is most common in older patients.



CASE HISTORY


The history is usually relatively straightforward. The owner has probably been aware of a cloudy appearance to the eyes for weeks or even months, which is getting progressively more noticeable. They initially assume that the dog is just getting old, or developing cataracts, and it is only when the clouding becomes quite severe that they bring the pet along. It is normally otherwise well, with no relevant history of previous ocular problems. Thus it is not uncommon for the owner to comment on the appearance of the eyes in passing during an annual vaccination consultation for example.



CLINICAL EXAMINATION


General clinical examination is usually unremarkable. On ocular examination the eye(s) appear slightly blue–grey in colour and the cornea appears slightly dull. Menace responses are usually normal as are pupillary light reflexes. The view of the iris and anterior chamber is hazy due to the presence of corneal oedema which manifests as a blue–grey mottled appearance. No ulceration is usually present (unless the disease has progressed to bullous keratopathy with ulceration – see the later section on prognosis).


The oedema can affect just one quadrant (e.g. dorsolaterally) or the entire cornea, and can be uni- or bilateral (but is not usually symmetrical – one eye will probably be more severely affected initially). The corneal oedema outlines the shape of the cornea and this gives the false impression that the eye is ‘bulging’. Normally the cornea is completely transparent and its convex shape is not apparent – one sees the flat iris instead – both from in front and laterally. Once the outline is visible due to the oedema then the shape is more obvious and the appearance is of the eye bulging. This must be differentiated from globe enlargement due to glaucoma or exophthalmos causing the eye to be placed more anterior than usual. The corneal oedema gives a mottled appearance and by gently pressing the globe over the sclera (through the upper lids for example) the oedema becomes denser. Palpation in this way is unlikely to be painful – whereas with a case of glaucoma or severe uveitis causing the oedema the patient would resent such examination due to the discomfort this would cause. Conjunctival hyperaemia can be present but is normally only very mild, providing ulceration is not a feature. Similarly, no significant ocular discharge is normally present.


Intraocular examination is unremarkable – details might be hazy but the use of distant direct ophthalmoscopy will help to determine whether the lens is clear or is cataractous, while indirect ophthalmoscopy will assist in evaluating the fundus.




DIFFERENTIAL DIAGNOSES


(See Figure 26.1.)


image

Figure 26.1 Differential diagnosis for cloudy eyes.



• Glaucoma

• Keratitis

• Exophthalmos

• Corneal ulceration with oedema

• Corneal lipidosis

• Lipid keratopathy

• Cataract

• Anterior lens luxation with lens pressing on corneal endothelium causing oedema

• Uveitis causing oedema (e.g. canine adenovirus 1 associated)

• Retinal detachment resulting in leukoria

• Lipid-laden aqueous


CASE WORK-UP


Ophthalmic work-up for the case will include fluorescein testing and measurement of intraocular pressure. The latter will rule out both glaucoma and uveitis, although for both conditions other ocular abnormalities will be present along with the oedema. Thus the diagnosis of corneal endothelial dystrophy or degeneration is often one of exclusion. The patient is normally clinically well and, as such, further diagnostic work-up is not normally required.




NURSING ASPECTS


Many cases of corneal endothelial dystrophy do not require treatment. However, if the oedema is so severe that the animal is having visual difficulties, or if bullous keratopathy has developed, then treatment might be necessary. If this is with hypertonic sodium chloride it should be remembered that this often stings. Preventing rubbing immediately post-application is required and distracting the patient (e.g. by feeding or taking for a short walk) is helpful.

Related posts:

  1. Rabbit uveitis
  2. Proliferative (eosinophilic) keratoconjunctivitis
  3. Limbal melanoma
  4. Canine lens luxation

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Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Corneal endothelial dystrophy

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