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.


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

Myopia and anxiety

A friend who is a rehabilitation therapist in China told me some interesting observation he has had while treating myopic children. He noticed that for those children who are more anxious, their myopia progressed faster, versus those who are calmer. So he asked me whether anxiety and other psychological factors may contribute to myopia development and progression.

Now I know that when I was 10 and started becoming myopic, I had a lot of anxiety and depression, for the reason that I could not see the blackboard in class! Every school year we went to the hospital to have physical exam and the vision exam was the most anxiety-inducing. I would squint, guess, and peek at the tumbling E beforehand trying to memorize them. My face became red and my hands sweaty. Yes I am ashamed to admit that I cheated in the vision screening in elementary school to get away with a failed report to the teacher and my parents. Why did I do that? As a child I could not describe it exactly. But I did not want to wear glasses and became different from everyone else. Plus, as a straight A student, a failed test in any form was not acceptable.

More and more I found it difficult to see the board. I would nonchalantly walk up to the board then back to my seat (fortunately I sat in the middle so did not have to walk too long to disturb the other students). I would peek at my desk mate’s notes to see what’s going on. I became afraid of math classes because the numbers were small. Eventually I had to tell my parents that I had trouble seeing the board. I remember feeling ashamed when I had to tell them. It’s as though I contracted a disease that I should not have. Though the science at the time was not clear, at least to me, I knew that I was to blame for becoming near-sighted. I was always reading, day and night. Not necessarily school-related, but I was hooked by fictions, story books, magazines and newspapers, anything that had prints on them. Outside classroom, I would read on my own. During summer and winter vacation, I would still be reading books from the library. My dad who’s a teacher and scholar, was the role model that I took after. He did not stop my prolonged near work. My childhood home was very dark, with rather dim lighting. Plus my dad also had myopia though my mom had hyperopia. Thus odds were really against me and no surprise I was among the early ones in my class to wear glasses. That was in the early 1990s, at age 10 I developed myopia while majority of my classmates were still emmetropic. Today probably majority of kids in a 4th grade classroom are wearing glasses. Times have really changed.

I remember going to the hospital to have my eyes examined. The doctor put eye drops in my eyes, I had to wait for a long time, before someone put a strange-looking frame on my face and showed me a bunch of different lenses. I was asked to read letters on a chart, and I felt strange that I was able to see some tiny letters. I had to say that this cycloplegic trial frame refraction was up to American standard even to this day. Thanks to my small town ophthalmologist, I was finally able to see. I was -2.00 in both eyes that day and I no longer had to walk up to the board to see small prints.

Back to our question on myopia and anxiety. My own experience told me that as a myope without glasses, I definitely felt anxiety. After wearing glasses, my vision was back, but I felt a kind of depression because I had to rely on glasses and I hated having to glasses. I went through all 5 stages of grief: denial, anger, bargaining, depression and acceptance. I thought that if I looked far away long enough, my eyes would be back to normal. I was mad at myself for abusing my eyes without a break on those stupid books. I constantly regret it and promised I would trade in some years of my life in exchange for normal eyesight. I was depressed that I had to wear glasses and looked ugly. Eventually of course I accepted this imperfect aspect of me. After all, there were so many other things that were not perfect so why focus only on myopia?

As an optometrist, myopia is one of the most common conditions we treat. It’s so common we almost consider it ‘normal’, routine and benign. We rarely considered the psychological aspect of myopia, when in reality this condition hit children and adolescents, who are at a vulnerable age.

Now the science part of this article. Research has shown that myopic teenagers had more anxiety than their peers, and boys with myopia had more anxiety than girls with the same condition 1. However, personality profile and psychophysical stress do not seem to play a primary pathogenetic role in myopia 2. So that is good, you can feel tortured by the fact that you need thicker glasses, but the sadness alone does not make your eyesight worse.


1.            Łazarczyk JB, Urban B, Konarzewska B, et al. The differences in level of trait anxiety among girls and boys aged 13-17 years with myopia and emmetropia. BMC Ophthalmol 2016;16:201-201.

2.            Angi M, Rupolo G, De Bertolini C, Bisantis C. Personality, psychophysical stress and myopia progression. Graefe’s Archive for Clinical and Experimental Ophthalmology 1993;231:136-140.

Will eating sugar make myopia worse?

Myopia has become a global epidemic, affecting kids of school age, sometimes as early as 6 or 7. Left untreated, myopia may progress 1 diopter each year, resulting in high myopia when kids become adults. Myopia is not just an inconvenience, it is an eye disease that significantly increases a person’s risk of developing retinal detachment and myopic macular degeneration, both can lead to blindness.

Naturally parents become concerned when their kids fail the vision screening at school and have to wear glasses to see well. As food is a key part of our health, many often wonder if food contributes to myopia development. For example, does eating sugar and refined carbohydrates increase myopia? Surely sugar is bad for your teeth and just bad for your health in general. Is it also to blame for myopia?

Will sugar coma cause you to see worse?

When I was a student at New England College of Optometry in Boston, we learned extensively on myopia, which is a major topic of interest for optometry. While many factors affect myopia, for example, genetics, prolonged near work, lack of outdoor activities, sugar intake was never mentioned as a factor to affect myopia. Yes diabetes can affect a person’s vision by making them temporarily more myopic or hyperopic, but that is reversible and after blood sugar levels are controlled, the eye returns to baseline refractive state. Most people, especially school aged children, do not have diabetes or constantly fluctuating sugar levels. So is there any evidence for a role of sugar in myopia that is not in context of diabetes?

It turns out not many studies have been done on this topic. In 1956, Gardiner proposed that carbohydrates and fats in the diet could cause myopia 1, but this hypothesis was discarded later in the scientific community. When this happens, it’s either because not enough research was done to support it, or that it did not hold water by subsequent research. In deed there was a scarce of literature on this topic. But one actually found that more sugar intake did not increase risk of developing myopia in children 2. This study in turn, found out that too much saturated fatty acid in the diet correlated with more myopia.

Most recently a French study evaluated 180 children aged 4-18 via questionnaire about their diet habits, and discovered that for girls, more sugar and refined carbohydrates correlated with more myopia, but in boys, this was actually the opposite, that is, when boys eat more sugar/carbs, they show less myopia development 3. This type of study has flaws in that it relies on questionnaire which can be highly subjective. In addition, many variables were not controlled, such as outdoor time, reading and screen time. Even if it’s to be trusted, the study like many epidemiological studies, evaluate a correlation, not causation. Besides, how do you interpret the data that sugar reduces myopia risks in boys? Would you recommend boys to eat more sugar and refined carbohydrates? I don’t think so.

In summary, little evidence exists to indicate sugar or refined carbs increase or decrease risks of myopia. Maybe this is just a factor that has not much to do with myopia. To advocate better oral hygiene and health, we certainly want children to control their intake of sugar and refined carbs, possibly for everyone really, not just kids. However, if you think that by eating less sugar you will not develop myopia, you are up the wrong tree.


1.            Gardiner PA. The diet of growing myopes. Trans Ophthalmol Soc U K 1956;76:171-180.

2.            Lim LS, Gazzard G, Low YL, et al. Dietary factors, myopia, and axial dimensions in children. Ophthalmology 2010;117:993-997 e994.

3.            Berticat C, Mamouni S, Ciais A, Villain M, Raymond M, Daien V. Probability of myopia in children with high refined carbohydrates consumption in France. BMC Ophthalmol 2020;20:337-337.

Fake membrane

A man in his late 40s came in with blood shot and swollen eyes. 5 days ago while in the gym he rubbed his eyes after cleansers still on his hands. Since then each day both of his eyes were feeling worse with foreign body sensation, itchiness, pain and discharge. He went to urgent care 2 days ago, was given antibiotic drops and ointment, but felt it’s not helping. His conjunctiva (white part of eyes) were the most swollen that I had seen. Unfortunately I did not take a photo, but found one on the internet that quite resembled his eyes at the time as shown below.

Image 1. Conjunctiva chemosis (swollen conjunctiva). Image from

Cornea (black part of the eye) was clear. At the time I thought this was toxic/allergic conjunctivitis, so prescribed a steroid drop to use 4 times a day for 7 days. 

A week later, he came back, reporting improved symptoms (pain 3/10 from 5/10 previously), but still lots of discharge. This time, the swelling was gone, the redness almost resolved, but when I pulled his eyelid down, there were white pseudomembranes (fake membranes) in both eyes, more in one eye than the other. Below is again from internet, showing similar to what I saw.

Image 2. Conjunctival pseudomembrane, a white membrane developing inside the eyelid. Image from

Now this made me rethink the diagnosis. Pseudomembranes are often seen in infectious conjunctivitis caused by nasty bugs such as Corynebacterium diphtheriae, Neisseria gonorrhoeae, Streptococcus pyogenes and adenoviruses, some of these are highly contagious. I asked whether anyone else in the household developed pink eyes, and he said no. He had no systemic symptoms or swollen lymph nodes, which were a good sign. Pseudomembranes can also be caused by toxic and allergic agents, and even foreign bodies [reference 1]. So at this point I was still going with allergic conjunctivitis, but these other infectious causes were now on the back of my mind, making me uneasy. So I stopped the steroid drops and switched to an antibiotic/steroid combo drop, as well as adding an antibiotic ointment at night. Of course, the pseudomembrane had to be removed otherwise he would not get better.

1 week later he came back, this time he’s much better, no discomfort, not much discharge, no swelling or redness. Exam revealed residual tiny papillae, and the membranes were gone! 

To summarize, pseudomembranes can be caused by infections, toxins, foreign bodies or allergies, and to treat it the underlying cause needs to be addressed, and pseudomembranes need to be removed promptly.


[1] Ho D, Lim S, Kim Teck Y. Pseudomembranous Conjunctivitis: A Possible Conjunctival Foreign Body Aetiology. Cureus. 2020;12(5):e8176. Published 2020 May 18. doi:10.7759/cureus.8176

Gray floater in an elderly lady

Floaters can be so common, yet not all floaters are the same. Here is another example.

An 84 year old nice lady came for an urgent visit as she started noticing a greenish gray floater in the right eye for 1 week. She did not notice any flashes. Her right eye saw 20/400 with no improvement with pinhole (this usually means that vision cannot be improved with glasses). Her left eye was able to see 20/30.

It’s impressive that she had not had cataract surgery yet, and only had a moderate amount of cataract. One look at her macula in the right eye revealed why she saw this gray ‘floater’. There is a blob of blood there as shown in images below. 

Figure 1. New membrane (arrow head) and bleeding (***) in the macula of the right eye.

The other eye only had mild drusens in the macula, indicating early age-related macular degeneration.

So this may be a case of very asymmetrical presentation of AMD with the right eye affected by wet AMD with acute bleeding and vision loss, and left eye only affected by mild dry AMD.

I referred her to a retinal specialist for treatment.

See my other articles on “floaters” and related eye phenomena.

Does ortho K increase risk of glaucoma?

The ortho K lens is popularly used to reshape cornea, correct vision and slow myopia progression. Read my previous post here (

People are often concerned about potential side effects or complications of wearing ortho K lenses. We previously discussed that corneal infection is a concern, but proper hygiene and care minimize this risk. It is a hard lens that touches on the cornea, will this have any effect on glaucoma or eye pressure of the eye? A colleague of mine recently saw an 18 year-old patient interested in ortho K for his myopia, who has a family history of glaucoma, and showing some questionable visual field finding himself. My colleague is worried about what ortho K may do to patient’s eye pressure and risk of glaucoma.

First of all, glaucoma is exceedingly uncommon among kids and young adults. Second, even if someone has glaucoma, it is not a contraindication for wearing ortho K lenses. Research has actually shown that wearing ortho K lenses overnight reduced eye pressure slightly [1, 2].

Of course, if you have glaucoma, you need to regularly see your glaucoma doctor to check eye pressure, health status of the optic nerve and visual field function, whether you wear any type of contact lens including ortho K lens or not. But people with or without glaucoma, if eligible for ortho K lenses, can certainly choose to wear them.


[1] M.R. Romano; A. Calossi; F. Romano; G. Ferraioli, Intra–Ocular Pressure After Overnight Orthokeratology, ARVO Annual Meeting Abstract, Investigative Ophthalmology & Visual Science May 2006, Vol.47, 2391

[2] Chang CJ, Yang HH, Chang CA, Wu R, Tsai HY. The influence of orthokeratology on intraocular pressure measurements. Semin Ophthalmol. 2013 Jul;28(4):210-5. doi: 10.3109/08820538.2013.768679. Epub 2013 Apr 29. PMID: 23627528.

Doc, my eyes still hurt, now what?

Recently a patient complained to me: ‘Doc, my eyes still hurt.’

I asked: ‘have you tried the artificial tears I recommended to you?

‘Yes, it doesn’t do any good.’

‘How many times did you put in a day?’

‘I just did that once and it did not work.’

‘I see. How about the warm compress?’

‘Not working either.’

‘How long did you do it and how many times a day?

‘Once or twice, I forgot.’

‘Are you taking the fish oil supplement?’

‘Yes. Did not feel any different.’

Here I have a patient who two months ago came to me for dry eye. He reported trying restasis from his previous eye doctor for months but no relief at all. Eye exam showed typical meibomian gland dysfunction (MGD) and poor tear film quality, without blepharitis or corneal staining. So this is a case of MGD-induced dry eye, that’s why I started him on eyelid warm compress 5 min x 2, and fish oil 1000 mg x 2 daily, with artificial tears as needed, up to 4 times daily. I asked him to follow up in 1 month. At which time he was not doing any of the things I asked, and of course his dry eye symptoms continued. After re-education, I asked him to do these consistently and follow up again in 1 month. He has probably done some of this now, but not consistently, and given up very quickly.

Rather than drilling him again for being more compliant with the treatment regimen, I offered him an alternative, which he clearly came looking for. I would like to refer him for a lipiflow treatment. I explained what it is, how it is done, and why it works. Then I told him that it’s not covered by insurance and may cost $1-2,000 for one session.

After a short moment of silence, he told me that he would like to give warm compress another try. And that he just started taking fish oil last week and would like to see if doing this for longer may help. I agreed, and asked him to return in 6 weeks to evaluate on progress.

No one likes having the dryness, foreign body sensation, redness, burning and tearing caused by dry eye. Fortunately there are effective treatments such as warm compress and artificial tears, and often these are enough to control dry eye symptoms. Unfortunately these treatments require consistent and long-term use. There is no cure for dry eye, which is a chronic condition and may require life-long management. When it comes to dry eye treatment, compliance is key. There are certainly those unlucky people who despite doing everything right still suffers from dry eye. But fortunately those are the minority.

For more information on dry eye and treatment, you can visit my previous posts and video.





OK镜,是一个硬的透气的隐形镜片,用于晚上睡觉时佩戴。镜片暂时性改变角膜的曲率(角膜是眼睛最前面那层薄薄的透明膜), 这样当第二天早上将镜片取出以后,会有十几小时内看东西清楚的状态,从而矫正视力,无需戴眼镜。



大量研究证明,OK镜确实能延缓近视发展。这里附上两篇综述,总结相关研究[1] [2],供学霸家长阅读。





OK镜是安全,不过由于OK镜是晚上戴的,有研究发现,OK镜的感染风险和普通晚上戴的隐形眼镜相同,都是0.077% [3],也就是说每一万戴OK镜的人里面有不到8个人可能发生感染。在验配者经过认证培训的前提下,使用经过FDA验证的镜片材料,只要使用者保持良好的护理习惯可以大大减少感染风险。同时父母的监督也很重要。另外佩戴者需定期就诊,根据医生建议更换镜片。


戴OK镜的确容易发生角膜染色 [4],但这些是角膜表面微小的缺陷,在干眼等常见眼表疾病中也会发生,这是戴OK镜需要定期检查的原因。长期佩戴OK镜,一切都正常的情况下,每年至少也要检查一次,观察眼表健康情况,检查视力。如果有严重的角膜染色,需要停止戴镜,治疗恢复后在医生的指导下重新佩戴[J2] 。





  • 注意卫生,接触镜片和眼睛之前一定要肥皂和清水洗干净手,擦手最好用不留纸屑的纸巾或不留纤维的毛巾,因为纸屑或者小的纤维可能会通过手传递到镜片上,然后进到眼睛里。
  • 晚上戴好镜片以后,需要清水彻底洗净眼镜盒,并风干。
  • 早上摘镜的时候,先用护理液在手心揉搓几下,然后放在新鲜护理液中,直到晚上使用。
  • 浸泡镜片的盒子每2-3个月更换一次。
  • 每3个月可以进行一次蛋白清洗,因为镜片上会不可避免沾上眼泪中的蛋白质等。推荐使用Menicon Progent(除蛋白护理液)。
  • 有条件可以每年更换一次新的镜片,即使镜片度数完全不变。


  • 有效控制近视发展
  • 只需晚上佩戴,白天完全无镜


  • 贵!国产的一只镜片大概3000-5000,美国进口的就要4000-8000了。不过,在美国一对镜片大概也在1000美元以上。
  • 麻烦!和普通软的隐形眼镜一样,必须每天戴、摘、护理; 如果不注意卫生清洁,感染的风险增大。
  • 疼!初戴起来疼、不舒服,但适应期过后,大部分人不再出现不适感。


1. Campbell E (2013) Orthokeratology: an update. Optometry & Visual Performance 1: 11-18.

2. Lipson MJ, Brooks MM, Koffler BH (2018) The Role of Orthokeratology in Myopia Control: A Review. Eye Contact Lens 44: 224-230.

3. Bullimore MA, Sinnott LT, Jones-Jordan LA (2013) The risk of microbial keratitis with overnight corneal reshaping lenses. Optometry and Vision Science 90: 937-944.4. Liu YM, Xie P (2016) The Safety of Orthokeratology—A Systematic Review. Eye & Contact Lens 42: 35-42.