Blindness: Assassins of eyesight

Evaluation of the self-eye examination method for health promotion

OBJECTIVE

To evaluate the self-eye examination practice as a tool to promote the ocular self-evaluation.

METHOD

Quasi-experimental study developed in a university of Piauí with sample of 324 students between January and May 2014. A team of thirteen researchers made observations during the self-examination followed by an ocular screening.

RESULTS

There was no agreement on the hypothesis of defense that the ocular exam could help to observe the eyes health, p-value>0.3. However, the exam was considered as easy to accomplish (99.7%) and that not only the physician can perform the eye exam (99.4%). The awareness about eye care is identified as the main purpose of this booklet (97.6%), (χ2= 186.01; p=0.001). The results highlight the booklet can be used in the teaching process of self-eye examination (84.6%). Although the defense that its fulfilment can replace the consultation with the ophthalmologist (23.8%%) cannot be accepted (χ2= 46.34), the self-exam must be done routinely (82.4%).

CONCLUSION

The results prove that the learning through virtual booklet is possible and supports self-care with the eyes by performing the self-exam.

A microscale optical implant for continuous in vivo monitoring of intraocular pressure

Intraocular pressure (IOP) is a key clinical parameter in glaucoma management. However, despite the potential utility of daily measurements of IOP in the context of disease management, the necessary tools are currently lacking, and IOP is typically measured only a few times a year. Here we report on a microscale implantable sensor that could provide convenient, accurate, on-demand IOP monitoring in the home environment. When excited by broadband near-infrared (NIR) light from a tungsten bulb, the sensor's optical cavity reflects a pressure-dependent resonance signature that can be converted to IOP. NIR light is minimally absorbed by tissue and is not perceived visually. The sensor's nanodot-enhanced cavity allows for a 3-5 cm readout distance with an average accuracy of 0.29 mm Hg over the range of 0-40 mm Hg. Sensors were mounted onto intraocular lenses or silicone haptics and secured inside the anterior chamber in New Zealand white rabbits. Implanted sensors provided continuous in vivo tracking of short-term transient IOP elevations and provided continuous measurements of IOP for up to 4.5 months.

Amacrine cells coupled to ganglion cells via gap junctions are highly vulnerable in glaucomatous mouse retinas

We determined whether the structural and functional integrity of amacrine cells (ACs), the largest cohort of neurons in the mammalian retina, are affected in glaucoma. Intraocular injection of microbeads was made in mouse eyes to elevate intraocular pressure as a model of experimental glaucoma. Specific immunocytochemical markers were used to identify AC and displaced (d)ACs subpopulations in both the inner nuclear and ganglion cell layers, respectively, and to distinguish them from retinal ganglion cells (RGCs). Calretinin- and γ-aminobutyric acid (GABA)-immunoreactive (IR) cells were highly vulnerable to glaucomatous damage, whereas choline acetyltransferase (ChAT)-positive and glycinergic AC subtypes were unaffected. The AC loss began 4 weeks after initial microbead injection, corresponding to the time course of RGC loss. Recordings of electroretinogram (ERG) oscillatory potentials and scotopic threshold responses, which reflect AC and RGC activity, were significantly attenuated in glaucomatous eyes following a time course that matched that of the AC and RGC loss. Moreover, we found that it was the ACs coupled to RGCs via gap junctions that were lost in glaucoma, whereas uncoupled ACs were largely unaffected. Our results suggest that AC loss in glaucoma occurs secondary to RGC death through the gap junction-mediated bystander effect. J. Comp. Neurol. 527:159-173, 2019. © 2016 Wiley Periodicals, Inc.