Optogenetic Treatment of Blindness Comes to Clinical Trials
The Dublin, Ireland pharmaceutical company Allergan has now treated a handful of people with retinitis pigmentosa by inserting a gene that enables algae to detect light into non-visual retinal cells. The patients can detect only blue light; reportedly, they are able to do things like sensing where a window is located in a room. The Scientist, Nov 16, 2017. At a London hospital, the French firm GenSight Biologics has enrolled the first of 18 patients in a similar trial. The gene enables detection of red light only, but the subjects will wear goggles with cameras that will convert other wavelengths to red. Recipients will see in monochrome, hopefully well enough to discriminate objects and detect obstacles. GenSight believes the procedure could be applicable to teating age-related macular degeneration as well. GenSight Biologics, Oct 26, 2018; New Scientist, Jan 16, 2018.

Stem Cell Treatment of Vision is Coming Into its Own
Research doctors are achieving important success in treating macular degeneration with stem cells. Over a year's time, three studies have reported implantation of either embryonic stem cells or adult stem cells induced to produce retinal pigment epithelium, which supports and nourishes retinal cells. The procedure prevented further loss and, in some patients, resulted in improved vision. Three patients, for example, increased the number of letters they could read on a vision chart by 17, 21, and 29 letters, while two people went from being unable to read at all to reading 60 to 80 words per minute with normal reading glasses. Nature Biotechnology, Vol 36, 328-337. New England Journal of Medicine, Vol 376, 1038-1046. Science Translational Medicine, DOI: 10.1126/scitranslmed.aao4097.

Gene Therapy for Age-Related Macular Degeneration
According to your text, gene therapy for blindness has been successful with animals, but is not ready for routine implementation in humans (p 282). However, recent studies have made major strides with age-related macular degeneration (AMD), which is the most common cause of vision loss in the western world. Injecting patients suffering from wet AMD with a gene to block a protein that causes the blood vessels to leak damaging fluid into the macula was found safe in a phase 1 trial; vision improved in 6 of 19 patients. Lancet, DOI: 10.1016/S0140-6736(17)30979-0. Another phase 1 trial has just begun treating ten patients with dry AMD, which is caused by the degeneration of cells in the macula. The inserted gene prevents this cell death; this is the first study to target the underlying genetic cause of AMD. News Medical, Feb 20. 2019.

Face Blindness is a Connectivity Problem
Although there is a specialized face processing area (the fusiform face area; see p 301 of the text), recognizing faces requres the participation of multiple brain areas. Researchers at Ben-Gurion University, Israel, scanned people with and without congenital prosopagnosia to find out how we recognize faces and how we don't. In the controls they found that the anterior temporal lobe served as a major network hub, with extensive connections to frontal and posterior areas of the brain. The subjects with prosopagnosia lacked these connections; instead, they had a high number of connections in the posterior visual cortex, mostly involving the lateral occipital and inferior temporal cortices. The extent of these atypical connections increased with the severity of the face recognition deficit, and may have developed as a partial compensation. bioRxiv, DOI: 10.7554/eLife.25069.

Synesthesia More Common Than We Thought
Everyone thought synesthesia was rare until Julia Simner reported that 5% have some kind of synesthetic experience (text, p 305). Now in an online study of 4,000 respondents, 22% tested positive for one of the 60 identified types of synesthesia, visually-evoked auditory response (referred to as vEAR). In vEAR, visual motion or flashes of light evoke faint auditory sensations. This result is consistent with previous, much smaller studies, which estimated the phenomenon at around 20%. Cortex, Vol 103, 130-141.
You can see examples of stimuli that evoke the response in some people, and find a link to the online test that was used here.