A few posts ago I showed you an owl with equal pupils but this poor little Staffie cross puppy has unequal eyes and a certain degree of visual comrpomise. What is happening here do you think?
Alfie’s right eye is too big and his left eye is too small – megophthalmos and microphthalmos you might say. Many ophthalmologists will argue that I should say buphthalmos (literally ox eye) or hydrophthalmos, but both those terms imply an increased intraocular pressure or congenital glaucoma. In fact neither eye has an increased pressure. In fact what they are also missing is a lens!
I performed an ultrasound scan to measure the size of the globes but blow me down, I couldn’t find a lens in either eye! Aphakia as part of a syndrome of multiple congenital anomalies has been reported in the veterinary literature (Martin and Leipold Aphakia and multiple ocular defects in saint bernard puppies. Veterinary Medicine Small Animal Clinician 69:448-453 and Bergsjo et al Congenital blindness with ocular developmental anomalies including retinal dysplasia in Doberman Pinscher dogs. JAVMA 184:1383-6) but those were in 1974 and 1984 so its not that common!
Aphakia is rare in people too with one recent paper reporting a mutation in a gene central to development of the lens placode (Anjum et al A mutation in the FOXE3 gene causes congenital primary aphakia in a an autosomal recessive consanguineus Pakistani family. Molecular Vision 16: 549-555). Whether a similar gene defect is occuring here awaits out investigations!