The white fluffy material is seen in many tissues both ocular and extraocular, such as in the anterior chamber structures, trabecular meshwork, central disc, zonular fibres, anterior hyaloid membrane, pupillary and anterior iris, trabecula, and occasionally the cornea. The flakes are widespread. One report suggested that the granular flakes were from abnormalities of the basement membrane in epithelial cells, and that they were distributed widely throughout the body and not just within structures of the eye. There is some research suggesting that the material may be produced in the iris pigment epithelium, ciliary epithelium, or the peripheral anterior lens epithelium. A similar report suggests that the proteins come from the lens, iris, and other parts of the eye. A report in 2010 found indications of an abnormal ocular surface in PEX patients, discovered by an eye staining method known as rose bengal. PEX can become problematic when the flakes become enmeshed in a "spongy area" known as the trabecular meshwork and block its normal functioning, and may interact with degenerative changes in the Schlemms canal and the juxtacanalicular area. The blockage leads to greater-than-normal elevated intraocular pressure which, in turn, can damage the optic nerve. The eye produces a clear fluid called the aqueous humor which subsequently drains such that there is a constant level of safe pressure within the eye, but glaucoma can result if this normal outflow of fluid is blocked.
In adults, such primary causes include: dietary choices such as insufficient dietary fiber or fluid intake, or behavioral causes such as decreased physical activity. In the elderly, common causes have been attributed to insufficient dietary fiber intake, inadequate fluid intake, decreased physical activity, side effects of medications, hypothyroidism, and obstruction by colorectal cancer. Evidence to support these factors however is poor.Secondary causes include side effects of medications such as opiates, endocrine and metabolic disorders such as hypothyroidism, and obstruction such as from colorectal cancer or ovarian cancer. Celiac disease and non-celiac gluten sensitivity may also present with constipation. Cystocele can develop as a result of chronic constipation. Diet
Constipation can be caused or exacerbated by a low-fiber diet, low liquid intake, or dieting. Dietary fiber helps to decrease colonic transport time, increases stool bulk but simultaneously softens stool. Therefore, diets low in fiber can lead to primary constipation. Medications
Many medications have constipation as a side effect. Some include (but are not limited to) opioids, diuretics, antidepressants, antihistamines, antispasmodics, anticonvulsants, tricyclic antidepressants, antiarrythmics, beta-adrenoceptor antagonists, anti-diarrheals, 5-HT3 receptor antagonists such as ondansetron, and aluminum antacids. Certain calcium channel blockers such as nifedipine and verapamil can cause severe constipation due to dysfunction of motility in the rectosigmoid colon. Supplements such as calcium and iron supplements can also have constipation as a notable side effect. Medical conditions
Metabolic and endocrine problems which may lead to constipation include: pheochromocytoma, hypercalcemia, hypothyroidism, hyperparathyroidism, porphyria, chronic kidney disease, pan-hypopituitarism, diabetes mellitus, and cystic fibrosis.