• What is the problem/issue being addressed? Why is it important for society?
The use of topical eye drops is the most common treatment for glaucoma. However, these eye drops can enhance Dry Eye Disease (DED), which can cause non-adherence to the treatment, leading to loss in vision. It is also known that environmental conditions to which the patient is exposed to may play an important role. It is therefore possible that patients with glaucoma exposed to adverse conditions present a higher risk of non-adherence to treatment.
DED has generally been overlooked in glaucoma patients as clinicians are focused on treating the disease. Reducing ocular surface problems should improve adherence to treatment with better prognosis. In this project we evaluated the ocular surface characteristics of participants with glaucoma and healthy eyes using not only clinically accepted tests but also other promising new technologies to assess DED.
The main objectives of the study were:
• To assess the possibility of using new tests such as ocular thermography to study the ocular surface in glaucoma and healthy participants.
• To assess the effect of the environmental stress on the ocular surface of glaucoma and healthy participants. To examine the ocular surface in glaucoma and healthy participants subjects using clinically established objective and subjective tests.
To address the above, ocular surface signs and symptoms related to DED were evaluated under comfortable environmental conditions, before and after being exposed to controlled environmental stress.
The data obtained show a clear difference in the ocular surface characteristics between glaucoma and healthy participants. The results of the first ENCOGLAP paper showed that just after opening the eye, the ocular surface of glaucoma subjects is cooler. In addition, after a blink, when the participants keep their eyes open, the temperature decreases faster in glaucoma compared to healthy subjects. This may be explained by a decrease in perfusion pressure and it also seems to be related to tear instability, which is likely induced by the use of glaucoma eye drops.
We also found that although the baseline measurements (under conformable environmental conditions) showed more DED signs in the glaucoma group, the exposure to low humidity produced a quite similar effect in both groups in terms of clinical tests. However, the dynamical thermal parameters evaluated (cooling rate and thermal entropy) were affected by the environmental stress only in the control group. In addition, the study showed that the exposure to low humidity increases ocular discomfort, which may increase the risk of low adherence to glaucoma treatment.
In addition, we performed a parallel study that is also related to this project, in the sense that it includes the evaluation of the ocular surface using new technologies. As telemedicine is becoming popular and many clinicians use mobile phone to collect images of different eye conditions, we compared the objective evaluation using machine learning with the subjective evaluation performed by clinicians of images of ocular redness taken with three different mobile phones. The results showed that, if the images are not going to be evaluated by a clinician, the cameras of the phones must be calibrated to obtain reliable results.
