RM is associated with histological changes that include: an increase in the number of lymphocytes and fibroblasts, epithelial cell denudation, epithelial edema, goblet cell hyperplasia, increased expression of the epidermal growth factor receptor, increased mucus production, nasociliary loss, inflammatory cell infiltration, and squamous cell metaplasia.Direct acting sympathomimetic amines, such as phenylephrine stimulate alpha adrenergic receptors, while mixed-acting agents, such as pseudoephedrine can stimulate both alpha and beta adrenergic receptors directly and indirectly by releasing norepinephrine from sympathetic nerve terminals. At first, the vasoconstrictive effect of alpha-receptors dominates, but with continued use of an alpha agonist, this effect fades first, allowing the vasodilation due to beta-receptor stimulation to emerge.2-Imidazoline derivatives, such as oxymetazoline, may participate in negative feedback on endogenous norepinephrine production. Therefore, after cessation of prolonged use, there will be inadequate sympathetic vasoconstriction in the nasal mucosa, and domination of parasympathetic activity can result in increased secretions and nasal edema. Evidence suggests that if oxymetazoline is used only nightly for allergic rhinitis (instead of more frequent dosage as may be directed on product label), it may be used longer than one week without high risk of rhinitis medicamentosa especially with use of intranasal steroid like fluticasone furoate. Treatment
The treatment of RM involves withdrawal of the offending nasal spray or oral medication. Both a "cold turkey" and a "weaning" approach can be used.
Persistent hyperplastic primary vitreous (PHPV), also known as persistent fetal vasculature (PFV), is a rare congenital developmental anomaly of the eye that results following failure of the embryological, primary vitreous and hyaloid vasculature to regress. It can be present in three forms: purely anterior (persistent tunica vasculosa lentis and persistent posterior fetal fibrovascular sheath of the lens), purely posterior (falciform retinal septum and ablatio falcicormis congenita) and a combination of both. Most examples of PHPV are unilateral and non-hereditary. When bilateral, PHPV may follow an autosomal recessive or autosomal dominant inheritance pattern. Symptoms
The primary vitreous used in formation of the eye during fetal development remains in the eye upon birth and is hazy and scarred. The symptoms are leukocoria, strabismus, nystagmus and blurred vision, blindness. Causes
Trisomy 13 (Patau syndrome)
Norrie disease
Walker-Warburg syndrome
Autosomal dominant
Autosomal recessive

Diagnosis
Causes a white reflex in the affected eye (leukocoria), prompting further investigation. Treatment
Pars plana lensectomy with or without vitrectomy and trabeculectomy. See also
Persistent tunica vasculosa lentis

References
External links

GeneReviews/NIH/NCBI/UW entry on NDP-Related Retinopathies