When Nothing's Ever Seen Trivia Quiz

Answer:

Protanomaly, tritanopia and achromatopsia are three types of color vision defects, in ascending order of severity. Protanomaly is a partial form of red-green blindness in which the perception of long wavelengths (reds) is reduced but not entirely lost. It can range from mild to near-complete. Like all red-green disorders it is inherited via the X chromosome and affects males more often than females. Tritanopia is the complete inability to see blue light, caused by a genetic anomaly in chromosome 7, thus males and females are equally frequently affected. Finally, achromatopsia is the (very rare) complete inability to see color, often coupled with a severe loss of bright-light vision as the retinal cones are absent or nonfunctional and thus only the more sensitive, easily overloaded rod cells convey any information.

Retinopathy is a general term for damage to the retina, which is usually irreversible and progressive. A common cause for retinopathy is diabetes mellitus, often leading to full blindness. Retinal detachment is one of the forms of retinopathy that is initially reversible although it requires quick medical intervention to prevent loss of vision.

Retinitis pigmentosa is a genetic disorder which gradually leads to loss of night and peripheral vision, leaving patients with a very small visual field (tunnel vision), resulting in legal although rarely total blindness.

Nyctalopia is known as night blindness, either congenital or acquired by a loss of the highly sensitive rod cells, thus restricting vision under low light conditions, often also accompanied by a shrinking field of vision (as rods are more prevalent in the periphery of the retina).

Macular degeneration has mostly the opposite effect: in this disease, the cones in the macula (the area of greatest visual acuity) die off or lose sensitivity, losing central and color vision. While it leaves peripheral vision intact, it often leaves patients unable to focus well or recognize faces and objects. It is often a side effect of age.

Cataracts cause the loss of transparency in the lens of the eye. They also primarily affect older people and are correctable with surgery.

Myopia is better known as short-sightedness, an inability to see well into the distance, usually caused by a congenital or childhood deformation of the eyeball which grows too long, thus making the lens and cornea to have too short a focal length for the actual size of the eye. In all but the most severe cases, it is correctable with glasses or contact lenses.

Aniridia is a congenital malformation of the eye in which the iris (the colored membrane enabling the pupils to constrict in bright light) is absent. It is often accompanied by other malformations and causes vision less of varying degree depending on the exact manifestation, with vision most reduced in bright light.

Albinism is a genetic disorder leading to a loss of pigmentation in the skin and other organs. This also affects vision, due to higher scattering of light in the eye, a reduced effect of the iris and often optical nerve malformation. Vision loss is usually not progressive although exposure to bright light can cause additional damage. While aniridia and albinism cannot be cured, wearing tinted glasses can somewhat help sufferers.

Uveitis is an acute condition, caused often by autoimmune reactions, in which the pigmented layer around the eye becomes inflamed. While this is, in itself, not a cause of vision problems, it can quickly affect other parts of the eye, possibly causing complete blindness as a side effect. It requires prompt treatment, especially when presenting with acute onset, and is one of the leading causes of blindness (up to 20%).

Xerophthalmia is a disease characterized by a pathological dryness of the eye due to a lack of tear production, often caused by a Vitamin A deficiency. Untreated, it leads to permanent scarring and irreversible damage to the cornea as well as possibly the retina. While the corneal defects (which can result in severe vision loss) can be corrected with a transplant, retinal damage cannot be undone.

Glaucoma does not actually affect the eye itself but rather the optical nerve, although it typically originates in increased eye pressure. In many cases, it is gradual, leading to blindness only over several decades, but acute cases due to blockage of a canal draining intraocular fluid exist and need immediate treatment. Untreated, the increased pressure causes irreversible pressure damage to the optical nerve and, thus, blindness.

The remaining two options - onchocerciasis and trachoma - are the most common infectious diseases that can cause blindness.

Onchocerciasis is a ringworm infection which mainly affects the skin, but also causes changes to the cornea, causing it to lose its transparency and thus causing blindness. As the worms and the flies that transmit them are prevalent near rivers, it is also known as river blindness. Ivermectin can halt and ultimately cure the infection by taking a course several times a year for over a decade, relieving skin symptoms and preventing further vision deterioration. Corneal damage could be reverted by a transplant, but this is unlikely to be available in the mostly Central African areas where onchocerciasis is prevalent.

Trachoma is a bacterial infection of the eyelids that can easily spread to the cornea, irreversibly damaging it. It can also damage the eyelids themselves to an extent where they turn inward and thus block the eye. The latter condition can be ameliorated by surgery while the infection itself responds well to antibiotics. Like onchoceriasis, it is most prevalent in the poor countries of Central Africa.

As to the incorrect options: otosclerosis, cholesteatome and vestibular schwannoma are all conditions that can cause hearing loss, up to total deafness. Anosmia is the (congenital or acquired) loss of smell, often caused by damage to the olfactory nerve, dysgeusia is an abnormal sense of taste, often experienced by those who had a COVID-19 infection and allodynia is a condition in which normally non-painful stimulation suddenly leads to, often strong, pain - temporary allodynia is often experienced in sunburn sufferers when the slightest touch can cause strong, burning pain.