The underlying photoreceptor cells, rod cells and cone cells, are usually not damaged unless the membrane becomes quite thick and hard; so usually there is no macular degeneration. Cause
The source of the cells in epiretinal membranes (ERM) has been found to comprise glial cells, retinal pigment epithelial (RPE) cells, macrophages, fibrocytes, and collagen cells. These cells are found in varying proportions. Those from retinal breaks, previous retinal detachments, or cryopexy are composed mainly of dispersed RPE cells, while cells of glial origin predominate in idiopathic pathology. Laminocytes are the fundamental cell type in idiopathic ERMs. These cells are frequently found in small and dispersed numbers in eyes containing a PVD. The presence of retinal pigment cells invariably indicates proliferative retinopathy and is only seen in association with a retinal detachment or tear. The incidence of associated PVD range from 75 to 93%, and PVD is present in virtually all eyes with retinal breaks or retinal detachments and subsequent ERM formation. PVD can lead to retinal breaks that may liberate RPE cells that initiate membrane formation. Small breaks in the internal limiting membrane (ILM) after PVD also may provide retinal astrocytes access to the vitreous cavity, where they may subsequently proliferate. Many ERM also have ILM fragments that may be peeled separately. Finally, vitreous hemorrhage, inflammation, or both associated with a PVD also may stimulate ERM formation. Both sexes appear to be affected equally frequently. Diagnosis
Epiretinal membrane is typically diagnosed by appearance with optical coherence tomography (OCT) of the macula.
Familial nasal acilia is a rare congenital defect which is characterized by the complete absence of cilia on the epithelial cells of the respiratory tract. Symptoms are common within ones family and start as soon as one is born, with signs such as respiratory distress, dyspnea, lobar atelectasis, bronchiectasis and neo-natal pneumonia. Other symptoms that occur later in life include chronic moist coughing, chronic sinusitis, chronic otitis media, chronic rhinitis, and recurrence of upper and lower respiratory tract infections.Exact prevalence is unknown, OrphaNet estimates this condition to affect less than 1 out of every million people worldwide. R Soferman et al. described this disorder to be "autosomal recessive". == References ==