Changes of Choroidal Thickness in Children after Short-Term Application of 1% Atropine Gel

Choroidal thickness under pilocarpine versus cyclopentolate

Bruch´s membrane (BM) is firmly connected posteriorly to the optic nerve head through the peripapillary choroidal border tissue, and anteriorly through the longitudinal ciliary muscle to the scleral spur. We assessed, whether a difference in the contractile state of the ciliary muscle influences the position of the posterior BM by lifting the posterior BM pole, i.e., induces changes in the subfoveal choroidal thickness (SFCT). Healthy young adult individuals received one drop of cyclopentolate 1% into their right eyes and one drop of pilocarpine 1% into their left eyes. Using optical coherence tomography (OCT), three examiners measured independently SFCT and choroidal thickness in the fundus midperiphery at baseline and 30 min after eye drop instillation. The study included 21 healthy individuals (age:21.9 ± 2.6 years; range:15.7-25.8 years; axial length:24.4 ± 1.2 mm). In the right eyes, SFCT changed by 8.7 ± 34.9 μm (examiner 1), -2.9 ± 18.6 μm (examiner 2), and 10.5 ± 21.8 μm (examiner 3), respectively, and the midperipheral choroidal thickness changed by -10.6 ± 25.9 μm (examiner 1), 0.9 ± 17.5 μm (examiner 2), and 4.2 ± 24.7 μm (examiner 3), respectively, without significant differences between the measurements taken before and after eye drop application (all P > 0.05). In the left eyes, SFCT changed by 5.8 ± 22.2 μm (examiner 1), 5.5 ± 36.5 μm (examiner 2), and 3.9 ± 29.5 μm (examiner 3), respectively, and the midperipheral choroidal thickness changed by -6.9 ± 47.9 μm (examiner 1), -3.5 ± 28.7 μm (examiner 2), and 16.0 ± 28.2 μm (examiner3), respectively, without significant differences between baseline and study end (all P > 0.05). Application of cyclopentolate 1% and of pilocarpine 1% did not result in a statistically significant change in choroidal thickness in young healthy adults.

The Macular Choroidal Thickness in Danish Children with Myopia After Two-Year Low-Dose Atropine and One-Year Wash-Out: A Placebo-Controlled, Randomized Clinical Trial

INTRODUCTION

Our aim in this work was to investigate the macular choroidal thickness (ChT) changes in 6-12-year-old Danish children with myopia during 2 years of low-dose atropine treatment and 1-year wash-out vs. placebo in an investigator-initiated, placebo-controlled, double-blind randomized clinical trial.

METHODS

Ninety-seven participants were randomized to either 0.01% for 2 years, 0.1% loading dose for 6 months followed by 0.01% for 18 months, or placebo, then a 1-year wash-out. The primary outcome was ChT in the sub-foveal and inner and outer superior, nasal, inferior, and temporal sectors. The secondary outcome was axial length (AL). Outcomes were measured at baseline and 6, 12, 24, and 36 months. One-way analysis of variance was used to detect baseline ChT differences between AL-stratified groups (< 24 mm, 24-25 mm, or > 25 mm). To determine the longitudinal changes in ChT and its effect on AL, all eyes were included in linear mixed modeling with individual eyes nested in the study ID as a random effect.

RESULTS

Longer eyes had significantly thinner ChT in all choroidal sectors (adj-P < 0.01) at baseline. There was no statistically significant change in any ChT sector after 3 years in the placebo group. Sub-foveal and nasal ChT in the 0.1% loading dose and 0.01% group were not significantly different from placebo after 2-year treatment. In the placebo group, a 1-mm increase in AL was significantly associated with a 47-µm thinner nasal ChT after 3 years (95% confidence interval (CI): - 55; - 38, adj-P < 0.001). A 10-µm thicker nasal choroid at baseline was associated with 0.13 mm (95% CI: 0.009; 0.017, adj-P < 0.001) less 3-year axial elongation.

CONCLUSIONS

The ChT in Danish children with myopia remained stable over the 3-year follow-up. A thinner choroid at myopia onset might predispose to increased axial elongation. Treatment with 0.01% atropine did not change the ChT. We speculate that low-dose atropine does not primarily reduce myopia progression via a choroidal mechanism.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03911271.

Eye Diseases: When the Solution Comes from Plant Alkaloids

Plants are an incredible source of metabolites showing a wide range of biological activities. Among these, there are the alkaloids, which have been exploited for medical purposes since ancient times. Nowadays, many plant-derived alkaloids are the main components of drugs used as therapy for different human diseases. This review deals with providing an overview of the alkaloids used to treat eye diseases, describing the historical outline, the plants from which they are extracted, and the clinical and molecular data supporting their therapeutic activity. Among the different alkaloids that have found application in medicine so far, atropine and pilocarpine are the most characterized ones. Conversely, caffeine and berberine have been proposed for the treatment of different eye disorders, but further studies are still necessary to fully understand their clinical value. Lastly, the alkaloid used for managing hypertension, reserpine, has been recently identified as a potential drug for ameliorating retinal disorders. Other important aspects discussed in this review are different solutions for alkaloid production. Given that the industrial production of many of the plant-derived alkaloids still relies on extraction from plants, and the chemical synthesis can be highly expensive and poorly efficient, alternative methods need to be found. Biotechnologies offer a multitude of possibilities to overcome these issues, spanning from genetic engineering to synthetic biology for microorganisms and bioreactors for plant cell cultures. However, further efforts are needed to completely satisfy the pharmaceutical demand.