No abstract

The inflation test has been proven to be a valuable tool for the investigation of corneal biomechanics, maintaining both integrity and geometry of corneal tissue.

Ocular thermography paves the way to become an effective tool for differentiating between the two different etiologies of dry eye syndrome.

Objective: It is understood that the ability to measure ocular temperature accurately will increase understanding of ocular physiology and should be a support in decision-making in classical diagnostic procedures. The use of ocular thermography offers great opportunities for monitoring the temperature of the anterior eye and analyzing the effects of certain pathologies on ocular surface temperature (OST). The aim of the present work is to measure the OST of 220 healthy normal subjects, stratified according to gender and age, in order to obtain a normal temperature distribution to be used as reference values when comparing healthy versus pathological conditions. Approach: The OST is measured from five regions, located over the whole area of the anterior eye, which correspond to particular anatomic structures, through a semi-automated procedure to post-process the infrared images. The relationship between OST and independent variables (forehead skin temperature, age, gender, level of physical activity, cardiovascular risk factors including sedentary lifestyle and smoking, laboratory temperature, and laboratory humidity) was investigated through linear regression models. Main results: The OSTs measured from the five different ocular regions are statistically different (p -value < 0.001), even when dividing our subjects into males and females, with the nasal cantus being the hottest region and the central cornea the coolest; when considering also the effect of age, stratifying our subjects into young, middle-aged and elderly, the OST decreases when age increases significantly. Statistical analysis based on linear regression models pointed out that age, forehead skin temperature, and lab temperature are the main factors to be taken into account when exploring the OST. Significance: As OST evaluation can be important in detecting different ocular pathologies, having precise details of the variation in temperature across the ocular surface and therefore a more detailed map of the OST adjusted according to subject characteristics and environment conditions could enhance early diagnosis and thus course of treatments.

Background. The aim of this study is to investigate the ocular thermographic profiles in age-related macular degeneration (AMD) eyes and age-matched controls to detect possible hemodynamic abnormalities, which could be involved in the pathogenesis of the disease. Methods. 32 eyes with early AMD, 37 eyes with atrophic AMD, 30 eyes affected by untreated neovascular AMD, and 43 eyes with fibrotic AMD were included. The control group consisted of 44 healthy eyes. Exclusion criteria were represented by any other ocular diseases other than AMD, tear film abnormalities, systemic cardiovascular abnormalities, diabetes mellitus, and a body temperature higher than 37.5°C. A total of 186 eyes without pupil dilation were investigated by infrared thermography (FLIR A320). The ocular surface temperature (OST) of three ocular points was calculated by means of an image processing technique from the infrared images. Two-sample t-test and one-way analysis of variance (ANOVA) test were used for statistical analyses. Results. ANOVA analyses showed no significant differences among AMD groups (P value >0.272). OST in AMD patients was significantly lower than in controls (P > 0.05). Conclusions. Considering the possible relationship between ocular blood flow and OST, these findings might support the central role of ischemia in the pathogenesis of AMD.