Crocodile tears

A man in his 30s came in because he saw flashes of light for 20 minutes two days ago.

He was having very blurry vision and could not focus as well at the time, but it all resolved on its own and he remained symptom-free. After a thorough dilated exam I determined that his retinas were completely normal and his symptoms were most likely from ocular migraine. 

Then he brought up something else completely unrelated. For three years now whenever he ate something his right eye would tear up and it’s always only the right eye. That eye was not red, itchy or painful, it simply teared up a bit. 

He did not have dry eye. And both of his eyes were white and quiet with no sign of tearing at the time. His description sounded almost like crocodile tear syndrome. This is a very rare condition where the nerve that supplies the salivary gland somehow also goes to innovate the lacrimal gland which secretes tears. When he’s having a meal his salivary gland gets a signal to start secreting saliva, and that cross talks to his lacrimal gland which makes his right eye tear up. This often happens after nerve injury when the nerve tries to repair itself and makes an inadvertent mistake. This is called aberrant nerve regeneration. But he denies any facial or head injury. He reports to be completely healthy and taking no medication. 

The treatment for crocodile tear syndrome is to inject Botox into the lacrimal gland so that a part of the gland doesn’t work and therefore not too many tears are produced. In his case this doesn’t really bother him so we will just monitor.

Can you use ortho K lenses and atropine together to control myopia?

We know that ortho K lenses and low dose atropine (0.01%) both can slow down the rate of myopia progression by about 50%. People often wonder whether by combining the two, we can slow down the progression even further.

Here is an article looking at a combo of the two in 73 Chinese children who have very fast myopia progression. They discovered that additional atropine 0.01% did not result in significant difference compared with ortho K lens alone in terms of axial growth.

This is disappointing. However, this study looked at children with fast myopia progression despite using ortho K lenses. Also only a small number of children were evaluated. In addition, this is a retrospective study, meaning authors looked at the data later, rather than a randomized controlled study, so there could be factors stewing the results.

Anyway, we await more studies to see whether the two have synergistic effect.

Reference:

Chen Z, Zhou J, Xue F, et al, Two-year add-on effect of using low concentration atropine in poor responders of orthokeratology in myopic children British Journal of Ophthalmology Published Online First: 11 March 2021. doi: 10.1136/bjophthalmol-2020-317980

Increased myopia among children during COVID-19

Covid-19 has really affected so many aspects of our lives. With all that isolation inside, and the remote learning with digital screens, parents worry about their kids’ health. Many worry this will do great havoc to their eyesight, and they are not wrong.

Research has shown that confinement to home due to covid-19 is associated with an increase in myopia. Scientists have been monitoring the refractive error of 123 535 Chinese children since 2015. While the refractive error was showing a pretty steady trend in kids 6 to 8 years of age from 2015 to 2019, there was a sharp and dramatic change toward myopia in 2020 (Figure 1). Many Chinese children already don’t get enough outdoor activities and spend way too much time studying, and the covid-19 put extra strain in terms of even further decrease of outdoor time and increase of screen time.

Figure 1. Young children show a dramatic increase in myopia in 2020 compared to previous years [1]. Figure from reference [1]

I only hope that with universal vaccination and a good hygiene habit that we have formed during the past year, children will be able to be back to school and enjoy normal outside activities soon. If you think you child may have trouble seeing, please bring them to an eye doctor.

[1] Wang J, Li Y, Musch DC, et al. Progression of Myopia in School-Aged Children After COVID-19 Home Confinement. JAMA Ophthalmol. 2021;139(3):293–300. doi:10.1001/jamaophthalmol.2020.6239