Month: September 2020

Does ortho K increase risk of glaucoma?

Leave a comment

The ortho K lens is popularly used to reshape cornea, correct vision and slow myopia progression. Read my previous post here (https://bostoneyeblink.com/2016/09/09/ortho-k-why-do-it-and-is-it-risky/)

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.

References:

[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?

Leave a comment

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.

Dr. Ding | Dry Eye Disease and Treatment

When artificial tears just don’t cut it – Other treatments of dry eye

Why are your eyes dry?

孩子近视除了戴眼镜，还有这个矫正方法

Leave a comment

中国学龄孩子从小学开始长期近距离用眼、或用眼不当，导致小学生近视率居高不下。生活中新冠时期，网课主宰学习方式，近视率进一步上升。为了不影响孩子日常生活和学习，多数家长会让孩子配戴相应度数的眼镜。

其实除了配戴眼镜，孩子解决近视的方法还有另外一个镜——OK镜。大量研究发现，OK镜和低浓度阿托品的使用可以控制近视的发展。今天我们单独来谈谈OK镜的优点和缺点。

OK镜是什么？

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。

这是OK镜的美妙之处，晚上戴镜，白天摘镜，佩戴第一晚，第二天就有明显的效果，不影响美观，也不影响运动。长期佩戴，可一定程度延缓近视的发展。

OK镜真的能够延缓近视发展吗？

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镜要一直佩戴吗？

OK镜是临时的，可逆的，可调整的，因此可以随时停，随时再开始。但延缓近视发展的效果，只有在佩戴期间才有作用，一旦停用，就会恢复为佩戴前的视力水平，也没有了延缓近视发展的效果。

如果眼睛发生过敏、感染等不适，比如发红、痒、疼痛、出现分泌物，那么需要暂停使用任何形式的隐形眼镜，找眼科医生进行治疗。直到症状完全消失才可以重新戴镜。这种暂时性停止佩戴，对于近视的加深可以忽略不计，因为近视是一个以年为单位发展的过程，不是一周两周就会加深度数的。

OK镜安全吗？会不会感染？

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。

OK镜对角膜有伤害吗？

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] 。

OK镜适合什么样的人群？

OK镜适合近视不超过600度，散光不超过175度的人。并不是说度数超过这个范围的人就不能使用，只是可能不能完全脱镜。

至于年龄，有进展性近视的儿童可以佩戴，50多岁的成年人也可以佩戴。只是成年人佩戴不是起到延缓近视发展的作用，而是白天能够脱离眼镜的生活。对于佩戴的青少年，重点要培养其遵守镜片护理、清洁、消毒说明以及正确佩戴的方法。

日常生活怎么维护OK镜？

  • 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。

OK镜的优点

  • 有效控制近视发展
  • 只需晚上佩戴，白天完全无镜

OK镜的缺点

  • 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。

参考文献

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.

近视怎么纠正和预防 (2/2)

Leave a comment

近视有什么办法治疗？

最常见的当然就是戴镜框眼镜或者隐形眼镜了。请注意小孩子一定要通过散瞳之后得到的度数才准确。而且也不要完全亲信自动验光仪的数字，必须结合手动检影、主观验光或者试戴镜的检查手段多方面验证确定最终度数。

18岁以后（或者度数稳定之后）可以进行角膜激光手术矫正手术，见角膜手术一文。

这些方法都能矫正视力，但是并不能改变眼轴长度。目前认为，眼轴一旦增长似乎是不可逆的。幸运的是，现代的视光医学研究发现有几个方法可以延缓甚至停止眼轴继续增长。角膜塑形镜（orthokeratology, 俗称OK镜）是最有效的物理手段，而低浓度阿托品眼药水是最有效的药物方法。

OK镜我会单独开一篇文章讲讲。这是一种硬的可透气的隐形眼镜，夜间佩戴至少8小时，早上起床以后摘下。角膜在晚上被压平，因此暂时改变眼睛的屈光度，在整个白天这种屈光度能够维持，因此近视患者在白天无需戴眼镜也可以清楚的看到远处。这有点类似可逆LASIK，没有实际切削角膜组织，只是用隐形镜片将角膜临时压扁。如果停止使用，一周后角膜就会完全恢复常态。

OK镜于1994年FDA批准。临床研究效果显著，儿童使用两年眼轴增长能够减少45% [1]；而且实验结果经得起重复 [2, 3]。目前临床应用广泛，不仅在研究中有着显著的效果，身边的例子也有着很高的成功率。我的一些视光医生朋友非常推崇。最让我印象深刻的是一个国内朋友自己的例子。他900度近视，他妻子接近2000度近视，所以他们很担心小孩的眼睛。当他们的女儿9岁时近视达到200度，经过研究他们带她去配了OK镜，戴了5年，度数没有变化！我知道OK镜每年可以减缓近视25-50度，但是这样的家族史，5年没有加深还是很惊人的。要注意的是，人与人之间的差别很大，的确也有少部分人效果一般或者没有效果。造成这种差异的原因以及我们怎么能够个性化的治疗近视也是现在研究的一个热点。

低浓度阿托品也眼药水也可以有效的减缓近视的发展，效果和OK镜类似甚至更加好一点点。阿托品虽然是一个用了很多年的药，它的控制近视这一目的目前还没有通过FDA批准。当前的研究表明低浓度阿托品眼药水在几年内持续使用是安全的 [4]，但是远期副作用还没有数据。在美国，低浓度阿托品眼药水需要处方，并且只有特定的药房可以配制。

怎么发现孩子是不是开始近视？

有的孩子会抱怨说看黑板或者看电视模糊。但是小孩往往不知道自己看东西模糊，他们以为大家都是这样的。家长应该注意这些现象：看电视眯着眼，斜着眼看东西，或者不愿意在外边玩（因为在户外玩耍主要需要好的远处视力）。

美国视光协会推荐儿童应该在3岁的时候进行全面眼睛检查，在上小学以前全面检查一次眼睛，然后如果没有任何问题包括眼睛疾病、屈光不正和弱视的风险则可以每两年检查眼睛一次。如果儿童开始发展近视，则应该每年检查眼睛，更新眼镜度数。

孩子近视了，怎么办？

尽早发现近视，早进行治疗和干涉，可以避免近视发展过深。

  1. 带孩子去眼科医生或者视光医生去做全面眼睛检查包括散瞳和眼底检查，确定度数，佩戴镜框眼镜。
  2. 不要以为不戴近视眼镜或者戴故意矫正不足的眼镜可以减缓近视发展，研究表明恰恰相反，近视矫正不足会加快近视发展[5]。
  3. 18岁以下的儿童应该使用抗碰撞的聚碳酸酯材料制作的镜片以保护眼睛。
  4. 当孩子达到一定年龄，可以尝试隐形眼镜。但是一定要注意正确的佩戴、摘取和清洗护理，否则有角膜感染的风险。
  5. 如果对减缓近视的发展感兴趣，可以在视光医生的指导下使用OK镜。低浓度阿托品眼药水也是一个选择，但是目前没有通过FDA批准，远期安全性未知，需要承担风险。
  6. 等孩子18岁以后，又多一个选择，可以做LASIK。

有没有不花钱的办法可以控制近视？

不管是OK镜还是LASIK，价格都不菲。其实不花一分钱就可以预防或者减少近视的发展。

  • 实行用眼卫生（visual hygiene）。这本来是一个视觉训练的概念，但是用在防止近视照样有用。1）看书的距离不应该小于手指第二个关节和胳膊肘间的距离。2）记住20-20-20的规则。每看书或者近距离用眼工作20分钟，就看20英尺（大约6米）以外20秒。
  • 改进室内照明。昏暗的光线会造成视网膜上成像的模糊，加快眼轴生长。
  • 夜晚睡觉时不要开灯。规律的昼夜节律不仅有益身心健康，而且对眼睛的正常发育和正视化也是必要的。这一点，从刚出生的婴儿做起。
  • 多花时间呆在户外。如前所述，最新的研究发现每天两小时的户外活动会显著降低近视的发生。

需要指出的是，眼轴一旦增长，不能缩短，现有的方法都是防止眼轴进一步增长。以上的各种方法是有独立的研究和证据表明有效的。市面上可能有着各种各样的理疗器宣称治疗近视，我没有一个一个调查过，但是没有看到有独立研究（非商家赞助的研究）和证据表明它们有效。如果你看到有的广告宣传说能够缩短眼轴，那么这本身就是个伪命题。现在的研究者在积极寻求能够让眼轴逆生长的方法，可惜还没有找到。

近视是一个多因素的眼睛屈光不正问题。行为的改变可以有效的防止和减缓近视发展。最直接的例子是那些亚马逊流域部落的居民，以及我们的父辈那一代人（50年代出生的中国人），大部分人都是轻度远视。和肥胖一样，预防近视更应该是一个公众健康的问题，家庭、学校和社会推行用眼卫生和推广户外活动，能够减少大量的近视青少年，从而减少大量的近视中年人和老年人，能够给健康医疗系统减少很多花销和负担。遗憾的是，现代人的教育和生活方式，改变不是一朝一夕那么容易。和肥胖不同的是，近视从儿童期开始发展，一旦开始就不可逆，最多可以减缓发展。如果说减肥在受到充足教育的成年人里面可以成功，近视一旦形成，当我们变成懂事的成年人，都只有后悔年少的自己当年滥用了眼睛。时间不能倒流，也没有后悔药，因此防止近视要家长、学校和社会出大力气，抓住0-13岁这个窗口。

参考文献

1.            Li, X., et al., Update on Orthokeratology in Managing Progressive Myopia in Children: Efficacy, Mechanisms, and Concerns. Journal of Pediatric Ophthalmology and Strabismus, 2017. 54(3): p. 142-148.

2.            Walline, J.J., L.A. Jones, and L.T. Sinnott, Corneal reshaping and myopia progression. British Journal of Ophthalmology, 2009. 93(9): p. 1181-5.

3.            Chassine, T., et al., How can we prevent myopia progression? European Journal of Ophthalmology, 2015. 25(4): p. 280-5.

4.            Wu, P.C., Y.H. Yang, and P.C. Fang, The long-term results of using low-concentration atropine eye drops for controlling myopia progression in schoolchildren. Journal of Ocular Pharmacology and Therapeutics, 2011. 27(5): p. 461-6.

5.            Smith, E.L., 3rd, Optical treatment strategies to slow myopia progression: effects of the visual extent of the optical treatment zone. Experimental Eye Research, 2013. 114: p. 77-88.

Where is the pit?

Leave a comment

Juan Ding, OD, PhD

Our central vision is seen by a structure called macula in the retina, and the center of the macula is called a fovea. Normally there is a pit dipping down at fovea as shown in Figure 1 below, and this is important for normal central vision.

Figure 1. Normal foveal pit indicated by the arrow.

Yesterday I saw a kid that had abnormal, or under-developed fovea.

This 6 year old boy came with his foster mother. He had fair skin, blond hair and was very light-sensitive. Mom never noticed anything abnormal, but he failed the vision test at his pediatrician’s office and that’s why they came here. 

His vision was 20/50 and 20/40, normal eye alignment, minimum refractive error, but after cycloplegia about +4.00 of hyperopia. At any rate, this hyperopia should not cause reduced vision at his age. So what can it be?

Interestingly when I looked at his retina I could not see a foveal reflex. And the retina was really light in terms of pigment. I attempted OCT and with some luck, managed to get photos from this well-behaved 6 year-old. It is apparent that his macula is lacking a normal foveal pit (Figure 2, right and left eye, respectively). 

Figure 2. Lack of a foveal pit in right and left retinas in our patient.

I gave this a tentative diagnosis of ‘fovea hypoplasia’. This condition can be seen in ocular albinism (lack of melanin) or aniridia (lack of iris), or it can happen as an isolated condition. He has normal eye structures everywhere else. Combined with a blonde fundus and extremely fair skin, I do suspect albinism. But he has no nystagmus, and vision is very good if he does have albinism. Since he was adopted, we do not know much about his family history. Mom adopted him while he was 18 months, and noted good health and normal developmental milestones up to now.

Given moderate to high hyperopia, I gave him a prescription of reading glasses. I referred him to his pediatrician to consider genetic testing.