Vision is reduced to blacks, whites, and greys. Rod Monochromacy (Achromatopsia), when all three of the cones are non-functional and therefore photopic vision (and therefore color vision) is disabled.Monochromacy of photopic vision is a symptom of both Cone Monochromacy and Rod Monochromacy, so these two conditions are typically referred to collectively as monochromacy. Rod Monochromacy
Rod monochromacy (RM), also called congenital complete achromatopsia or total color blindness, is a rare and extremely severe form of an autosomal recessively inherited retinal disorder resulting in severe visual handicap. People with RM have a reduced visual acuity, (usually about 0.1 or 20/200), have total color blindness, photo-aversion and nystagmus. The nystagmus and photo-aversion usually are present during the first months of life, and the prevalence of the disease is estimated to be 1 in 30,000 worldwide. Since patients with RM have no cone function, they lack photopic vision, relying entirely on their rods and scotopic vision, which is necessarily monochromatic. They therefore cannot see any color but only shades of grey. Cone Monochromacy
Cone monochromacy (CM) is a condition defined by the exhibition of only one class of cones. A cone monochromat can have good pattern vision at normal daylight levels, but will not be able to distinguish hues. As humans typically exhibit three classes of cones, cone monochromats can hypothetically derive their photopic vision from any one of them, leading to three categories of cone monochromats:
Blue cone monochromacy (BCM), also known as S-cone monochromacy, is an X-linked cone disease.
History
Unlike rejection and infection, CAV in the transplanted heart was not initially a predicted outcome. Early survivors of heart transplants soon developed this form of vasculopathy of their coronary arteries, initially identified at post-mortems. There were early suggestions that preventing cytomegalovirus (CMV) infection could decrease the prevalence of CAV. The impact of CAV has changed over time, with early recipients being younger, having more rejection and cardiovascular risk factors and less use of statins. Later recipients used statins routinely and were introduced to the immunosuppressive agent mycophenolate mofetil (MMF) and CMV prophylaxis. In addition, the later recipients were monitored for antibody-mediated cardiac allograft rejection (AMR).Before 2010 there was no uniform international standards for the nomenclature of CAV. A consensus statement on a standard language for CAV was first published in 2010 by the ISHLT. This was devised in a similar way to the earlier acute rejection grading system by endomyocardial biopsy. Research directions
Antibody-mediated cardiac allograft rejection (AMR) is a significant factor leading to the rapid progression of CAV. Future research directions in this area may include prospective databases that correlate clinical factors with surveillance of the incidence and severity of AMR, the frequency of CMV infection, and the use of immunosuppressants. The role of inducing immune tolerance has yet to be established. == References ==