Scotopization and the Nagel-II anomaloscope

Inverse-Designed Aid Lenses for Precise Correction of Color Vision Deficiency

Color vision deficiency (CVD) is a common ocular disorder affecting more than 300 million people on the earth. Although no clinical cure for the disorder currently exists, some specialized color filtering glasses/lenses based on dyes, metasurfaces, or nanocomposites have been employed for CVD management. However, as CVD patients usually diversify in their classification and severity, none of the current lenses provides a customized correction for various CVD patients, resulting in undesirable correction effects. Here, we present an inverse-designed approach for the precise correction of CVD. The wavelength shift of a patient's abnormal cone photoreceptors was measured to inversely design the best blocking wavelength and blocking rate of the lens. Then the customized aid lenses were fabricated using silica-coated gold nanoparticles with appropriate sizes and concentrations, verified by the simulated color vision and human tests. This study demonstrates the potential of the inverse-designed aid lenses in precise color filtering and customized CVD management.

Pathologic scotopization: a shortened Nagel-II anomaloscopic micro-screw method

The Nagel-II micro-screw method uses eleven colour equations between 620 and 560 nm. The luminance settings are given and are based on the data of colour normal individuals. In the shortened version, intended to detect pathologic scotopization, it is ascertained at which position of the micro-screw the patient's colour adjustments drop beneath the level of 60 scale Units. A total of 64 patients was examined. 29 congenital colour defectives and 35 acquired colour defectives. With the shortened micro-screw method the patients can be divided into four groups: (1) a group without pathologic scotopization, which includes congenital protan defectives: (2) a group in which pathologic scotopization starts; (3) a group with evident pathologic scotopization, due to Stargardt's disease and other cone dystrophies; and (4) a group with complete pathologic scotopization, which includes the congenital achromats and the end-stages of the cone dystrophies.

Influence of pathologic scotopization on the extended Rayleigh match

Pathologic scotopization, an important symptom of retinal disease, can be studied by means of the Nagel II anomaloscope. This method is called the micro-screw method. The micro-screw method was performed in 14 congenital and 13 acquired colour vision defective individuals. The method proves to be useful in detecting symptoms of rod intrusion in colour vision under photopic conditions.

Scotopization and pseudoprotanomaly in blue-yellow/colour vision defects

With a routine clinical colour vision test battery we found scotopization in 32% of retinal diseases presenting with pseudoprotanomaly as sign of an acquired type III blue-yellow colour vision defect. In blue-yellow colour vision defects of retinal origin scotopization is a transient phenomenon, present in early stages of the disease, but it is not an obligatory finding. There is no evident relationship between visual acuity and scotopization.

An analysis of colour vision in 10,000 patients

Examination of a great number of patients resulted in the depth localisation theory. The combination of this theory with the fixation-eccentrisation theory is clinically useful: acquired colour vision defects can be subdivided by the fixation mode and by signs of receptor damage. There are indications that in multiple sclerosis the slowly progressive cases present with more receptor damage than the acute cases.