This systematic review examines the use of eye-tracking devices in optometry, describing their main characteristics, areas of application and metrics used. Using the PRISMA method, a systematic search was performed of three databases. The search strategy identified 141 reports relevant to this topic, indicating the exponential growth over the past ten years of the use of eye trackers in optometry. Eye-tracking technology was applied in at least 12 areas of the field of optometry and rehabilitation, the main ones being optometric device technology, and the assessment, treatment, and analysis of ocular disorders. The main devices reported on were infrared light-based and had an image capture frequency of 60 Hz to 2000 Hz. The main metrics mentioned were fixations, saccadic movements, smooth pursuit, microsaccades, and pupil variables. Study quality was sometimes limited in that incomplete information was provided regarding the devices used, the study design, the methods used, participants' visual function and statistical treatment of data. While there is still a need for more research in this area, eye-tracking devices should be more actively incorporated as a useful tool with both clinical and research applications. This review highlights the robustness this technology offers to obtain objective information about a person's vision in terms of optometry and visual function, with implications for improving visual health services and our understanding of the vision process.

In vivo corneal confocal microscopy (IVCM) is a non-invasive ophthalmic imaging technique that provides images of the cornea at the cellular level. Despite the uses in ocular surface pathologies, in the last decades IVCM has been used to provide more knowledge in refractive surgery wound healing, in neuropathies diagnosis, etc. The observation of the corneal cells, both normal and inflammatory, and the possibility of quantification of the corneal nerve density with manual or automated tools, makes IVCM have a significant potential to improve the diagnosis and prognosis in several systemic and corneal conditions.

Clinical relevance: Accurate measurement of several physiognomy parameters (interpupillary, nasopupillary and fitting height distances) and frame angles (pantoscopic and frame wrap angles) is essential for prescribing progressive addition lenses for presbyopic patients. Background: Few reports have described the repeatability of different devices commonly used to conduct essential measurements for prescribing progressive addition lenses. Methods: Interpupillary, nasopupillary (at far and near distances) and fitting point heights were measured three consecutive times in 21 healthy volunteers with four devices (traditional frame ruler, PD-5 interpupilometer, OptiCenter, and VisiOffice). Pantoscopic and wrap frame angles were also measured three times with Essilor standard pantoscopic ruler, Opticenter and VisiOffice. Results: The frame ruler, PD-5 and Opticenter showed better repeatability for interpupillary and nasopupillary distance (co-efficient of variation close to 1%, within-subject standard deviation or Sw < 0.50 mm) measurements at far and near distances than Visioffice (co-efficient of variation > 2%, Sw > 0.50 mm). Fitting point heights measurements showed worse repeatability with all devices (frame ruler: co-efficient of variation close to 5%, Sw = 0.46 mm; Opticenter co-efficient of variation > 5%, Sw > 0.80 mm; Visioffice co-efficient of variation > 10%, Sw > 1.50 mm). Pantoscopic angle measurements showed very low repeatability with the ruler and Opticenter (co-efficient of variation > 25%, Sw > 1.90 mm). The frame wrap angle showed unacceptable repeatability values with the ruler (co-efficient of variation > 10%, Sw = 0.49º) and Visioffice (co-efficient of variation > 60%, Sw > 2.50º), but acceptable repeatability with Opticenter (co-efficient of variation < 1%, Sw = 0.05º). Conclusions: Interpupillary and nasopupillary distance measurement showed acceptable repeatability with all the assessed methods; however, these measurements alone are no longer sufficient for free-form progressive addition lens prescription, which requires fitting point heights and pantoscopic and frame wrap angle measurement. Such measures display a lack of repeatability that could induce centration errors and could affect vision and/or adaptation of the user.

Purpose: To report the ocular surface pathology of patients suffering from acute/subacute mercury vapor intoxication. Design: Cross-sectional study. Participants: Male workers intoxicated with inorganic mercury referred for ophthalmic involvement and healthy control subjects. Methods: The following tests were performed: dry eye (DE)-related symptoms indicated by the ocular surface disease (OSDI) index questionnaire; tear osmolarity; analysis of 23 tear cytokine concentrations and principal component and hierarchical agglomerative cluster analyses; tear break-up time (T-BUT); corneal fluorescein and conjunctival lissamine green staining; tear production by Schirmer and tear lysozyme tests; mechanical and thermal corneal sensitivity (non-contact esthesiometry); and corneal nerve analysis and dendritic cell density by in vivo confocal microscopy (IVCM). Results: Twenty-two out of 29 evaluated patients entered the study. Most had DE-related symptoms (OSDI values > 12), that were severe in 63.6% of them. Tear osmolarity was elevated (>308 mOsms/L) in 83.4% of patients (mean 336.23 (28.71) mOsm/L). Corneal and conjunctival staining were unremarkable. T-BUT was low (<7 s) in 22.7% of patients. Schirmer test and tear lysozyme concentration were low in 13.6% and 27.3% of cases, respectively. Corneal esthesiometry showed patient mechanical (mean 147.81 (53.36) mL/min) and thermal thresholds to heat (+2.35 (+1.10) °C) and cold (−2.57 (−1.24) °C) to be significantly higher than controls. Corneal IVCM revealed lower values for nerve density (6.4 (2.94) n/mm²), nerve branching density (2 (2.50) n/mm²), and dendritic cell density (9.1 (8.84) n/mm²) in patients. Tear levels of IL-12p70, IL-6, RANTES, and VEGF were increased, whereas EGF and IP-10/CXCL10 were decreased compared to controls. Based on cytokine levels, two clusters of patients were identified. Compared to Cluster 1, Cluster 2 patients had significantly increased tear levels of 18 cytokines, decreased tear lysozyme, lower nerve branching density, fewer dendritic cells, and higher urine mercury levels. Conclusions: Patients suffering from systemic mercury intoxication showed symptoms and signs of ocular surface pathology, mainly by targeting the trigeminal nerve, as shown by alterations in corneal sensitivity and sub-basal nerve morphology.