Persistent Pupillary Membranes is caused when remnants of the fetal membrane, which nourished the lenses of the eye before birth, are seen in the puppy’s eye as strands of tissue. The strands can stretch from iris to iris, cornea to iris and sometimes they can be found in the anterior chamber of the eye. For many dogs, the strands do not cause any problems and generally the strands break down by 8 weeks of age. If the strands do not break down, they can lead to cataracts or in the case of a cornea to iris attachment, corneal opacities can occur. Treatment of Persistent Pupillary Membranes is usually a topical atropine to dilate the pupil if the strands do not atrophy naturally.