A colleague referred a blind hyperthyroid cat to me saying she expected to see complete retinal detachment, retinal haemorrhages and vessel changes but didn’t – why is it blind?
There isn’t a complete detachment for sure with billowing folds of retinal flapping in the breeze, as it were! But what there is, is a grey haze over what should be a bright tapetal reflection – this is protein insudate giving a flat retinal detachment with resulting blindness. Actually if you look ventrally there is a more severe retinal detachment, as shown below – the same was seen in the other eye.
The blood pressure was over 220mmHg confirming a diagnosis of hypertensive retinopathy and treatment with amlodipine at 0.625mg daily per os should reduce the blood pressure and hopefully reattach the retina. The pathology is probably more in the choroid than the retinal vessels, which explains why the appearance was not as was expected.