**1. Introduction**

Peter Piot, Belgian virologist, director of the London School of Hygiene and Tropical Medicine, and COVID-19 advisor to the EU Commission, himself became seriously ill with COVID-19 in mid-March 2020. Since then, the scientific expert on viral diseases has called himself an expert by experience, indicating his new perspectives on viral diseases. New perspectives often enable new insights and promote possible solutions. One of us (F.H.), an ophthalmologist, has recently been diagnosed with normal tension glaucoma, and here, too, the new perspective of an experienced expert could support the development of a new examination method.

Glaucoma is one of the most common causes of irreversible blindness worldwide [1]. It is characterized by progressive optic neuropathy and loss of retinal ganglion cells (RGC) and is associated with visual field (VF) defects. Several approaches are available that allow for reproducible assessment of functional vision loss [2]. Among these, standard automated perimetry (SAP) is a common standard subjective visual field test, but it has limitations, such as response variability [3]. In fact, there have been many recent developments in the field of VF testing in glaucoma and its utility in clinical practice, such as "portable brain-computer interface" [4] or "fundus-tracked perimetry" [5]. Recent evidence from functional and structural testing [6,7] indicates that the macula is affected at early stages

**Citation:** Müller, F.; Al-Nosairy, K.O.; Kramer, F.H.; Meltendorf, C.; Djouoma, N.; Thieme, H.; Hoffmann, M.B.; Hoffmann, F. Rapid Campimetry—A Novel Screening Method for Glaucoma Diagnosis. *J. Clin. Med.* **2022**, *11*, 2156. https:// doi.org/10.3390/jcm11082156

Academic Editors: Miriam Kolko and Barbara Cvenkel

Received: 4 March 2022 Accepted: 8 April 2022 Published: 12 April 2022

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of glaucoma. This suggests the importance of central visual field testing, e.g., the 10-2 SAP testing algorithm, for the earlier detection of central VF damage besides its pivotal association with quality of life in affected individuals [8–10]. This motivates further studies to provide better evidence-based guidelines for testing the central 10–20◦ of the visual field.

Conventional perimetry employed in testing VF limits the detectability of early VF defects in glaucoma and might not be optimal to aid in the salvaging of retinal ganglion cells (RGCs) from permanent damage. Early histological studies revealed that 20–40% of RGCs are lost prior to any detectable VF defects on conventional perimetry [11]. Several psychophysical techniques have been adopted, aiming to spot glaucoma damage at its earliest stages, including tests employing motion perception. Although not widely adopted, several studies have indicated abnormal motion perimetry in glaucoma [12,13], even at early stages, i.e., ocular hypertension [14,15].

In the present work, the perspective of an experienced expert (F.H.) served to explore a novel examination method for better understanding and earlier detection of VF defects based on the following case observation: In March 2017, F.H. observed a visual field defect on his right eye while rubbing the left eye. At the desk, a scotoma was identified as lying within the central 10◦ of the VF and was established as an arcuate scotoma in the superior temporal visual field, in analogy to locating the blind spot with a moving coin while fixating at a central point (Figure 1a). In June 2019, a second arcuate scotoma became apparent in the same eye (Figure 1a), it was unnoticed by Octopus 301 SAP (30◦, Figure 1b) and was confirmed by Humphrey Field Analyzer (HFA3) 10-2 testing, applying 68 test points in the central 10◦ visual field (Figure 1c). Attempts to make the perceived visual field loss subjectively more salient utilized the observation that a small light, travelling rapidly through the visual field defect, was perceived as interrupted in the area of the scotoma. This insight was translated into the VF-testing method, i.e., rapid campimetry, which is described in the present paper. As proof-of-concept, it was applied in an additional five subjects with advanced glaucoma-related visual field defects.

**Figure 1.** F.H. Visual field findings. (**a**) Sketch of the grey, drawn scotoma in the visual field of the right eye subjectively perceived by F.H. (first scotoma—one arrow, second scotoma—two arrows). (**b**) 30◦ field of view examined with Octopus 301. The scotoma is dark grey in the temporal upper field of view, the blind spot is shown in white. (**c**) 10◦ central visual field examined with the Humphrey Field Analyzer (HFA3). The absolute scotoma is black in the temporal superior visual field, and the relative scotoma is dark grey in the temporal and nasal superior visual fields. (**d**) Red and green dots, connected by a grey line, represent the beginning and end of the scotoma in the paramacular visual field after the screening procedure. One arrow marks the first scotoma, two arrows marks the second. (**e**) The 15◦ central visual field findings of scotoma delineation campimetry. After finding the two scotomas in the screening procedure, the exact scotoma borders were determined. The four grey spots

between the arcuate scotoma and blind spot (black) represent the presumed scotoma course. In this area, the test point is thicker than the narrow scotoma and therefore does not become invisible. When the test dot moves quickly, a brightness difference is perceived here, indicating the defect.
