Beh Optometry Clinic

29/04/2026

29/04/2026

这位 15 岁的病人星期天来领取她的新眼镜（图 1）。过去一年来，戴上别处做的眼镜她一直患有asthenopia（拉丁语：眼睛虚弱，英语：眼睛疲劳）和头痛。有人介绍她来我诊所验眼并建议她患有esophoria (英语：内移隐斜视)。

Phoria (隐斜视 ) 是一种潜在的眼球偏斜，平时病人的双眼保持正直。Esophoria是指眼睛在受到压力，累或视力模糊时向内偏移。这可以通过cover test（图 2a、2b）进行测检。

检查眼睛之后我发现她患有未矫正远视。她的度数：

右眼 +1.25/0（看到第 7 行字母）
左眼 +3.25/-0.50x180（第 6 行字母）

她去年在别处配的眼镜度数：

右眼平光（第 7 行字母）
左眼 +0.25/0（第 3 行字母）

她的眼睛同时受到两种有害的影响。首先是视力疲劳和头痛。远视时，视网膜上的图像(retinal image) 聚焦在视网膜后方（图3a）。Ciliary body (英语：睫状体肌肉) 必须收缩才能将图像重新聚焦到视网膜上（图3b）。肌肉持续不断的收缩导致了视力疲劳和头痛。由于左右睫状体收缩的幅度大致相同，当右眼视网膜图像聚焦时，因为度数相差200左眼视网膜图像就会模糊不清。长期如此，会导致左眼视网膜不活跃，出现 amblyopia (拉丁语：视力迟钝, 英语：弱视, 俗话：懒惰眼）。即使矫正远视度数，左眼视网膜仍旧模糊。

第二，ciliary body和medial recti 两肌肉（见图4）都由cranial nerve 3（CN3）控制。当ciliary body肌肉持续强烈收缩时，medial recti 肌肉也同时收缩，使眼球向内偏移。由于左眼远视度数较高，内移程度更大，而形成esophoria。

我们应该治本不治标。我配了一副准确的矫正远视眼镜，患者的ciliary body和medial recti 不需要再强烈收缩，已经恢复正常。无论是远或近，所有视力疲劳和头痛症状都消失。她的esophoria也显著改善。与此同时，她大脑还能把左右眼视网膜上的图像合并，使视力更加清楚，达到
了binocular vision (英语：双眼视觉)。这是一个非常好的显像。

我吩咐病人要长期佩戴新眼镜，以放松ciliary body和medial recti 肌肉。她的远视，弱视和esophoria等情况需要在6个月后复诊。这种长期性的病例往往的需要多次就诊才能彻底解决。

待续……

22/04/2026

My page "Guan Khar Beh" has been hacked. Please DO NOT respond to any demand from this page.

我的 page "Guan Khar Beh" 被人盗用，请不要回应此页面上的任何要求。

09/04/2026

This 15 year old patient came in to collect her spectacles on Sunday (image 1). She has asthenopia (Latin: weak eyes, English: eye stress) and headaches for the last year despite wearing spectacles, and was referred to me suggesting she has esophoria.

Phoria is a latent deviation of the eye. The eyes stay straight most of the time. It is different from tropia where the deviation is obvious. In esophoria, the affected eye will turn inwards when stresed or has difficulty to see. This can be detected clinically with the cover test (images 2a, 2b)

An eye examination revealed that she has medium uncorrected hyperopia. Her powers are:

R +1.25/0 (7th row of letters)
L +3.25/-0.50x180 (6th row)

Her spectacles made elsewhere from last year were:

R plano (7th row)
L +0.25/0 (3rd row)

There are 2 equally deterimental mechanisms to her eyes in play. First, the asthenopia and headaches. In hyperopia the retinal image is focused behind the retina (image 3a). The muscles in the ciliary body have to contract to refocus the image onto the retina (image 3b). Constant contraction caused asthenopia and headaches. Since the right and left ciliary bodies will contract together to about the same amount, when the right retinal image is focused, the left retinal image is unfocused/blurry. Over a long term, this causes amblyopia ex-anopsia (Latin: blunt eye from not seeing) in the left eye. The retina becomes inactive and blurry even when corrected.

Secondly, the ciliary body and the medial recti (plural, singular: re**us. See image 4) are controlled by the third cranial nerve (CN3). When the muscles of the ciliary body are contracting strongly all the time, the medial recti will contract in sync and pull the eyes inwards. As the left eye has a higher hyperopia, it deviates inwards further and so formed esophoria.

We always treat the root cause first, not the symptoms. By prescribing a pair of spectacles that correct the hyperopia fully, all the patient's asthenopia and headache symptoms have been eliminated. This is especially so with close work such as studying and using the computer where accommodation is required and the ciliary body contracts even more. Meanwhile, her esophoria has also reduced tremendously and there is binocular summation, where the brain combines both the right and left retinal images and amplifies them to be seen even clearer. This is an excellent sign.

The patient is instructed to wear her new spectacles at all waking hours. This will relax out the ciliary body. The hypeopia, left amblyopic eye and esophoria will need to be reassessed in 6 months' time. Usually a long standing case such as this requires several visits to be fully solved.

To be continued... 📅

29/03/2026

Always nice be appreciated. Thank you for your kind words.

12/11/2025

Please note that we close on Wednesdays and Thursdays. Thank you.

11/08/2025

This 18 year old patient came in to examine his eyes today. I noticed that he has an abnormal head posture which he said he had it for many years (see images 1a, 1b). His symptoms were general exhaustion and coordination problems like difficulty in threading a needle. However, his myopia was very low, right eye -0.50/0, left eye -0.25/0. I suspect there has to be a more sinister problem than just myopia alone.

A cover test revealed that there is significant hypophoria of the right eye, which measured to 6Δ prism diopters (images 2a, 2b).

Unlike squints, phorias are latent (hidden) deviations of the eye, so the eyes appeared straight under normal circumstances. When covered, the problem right eye will deviate to its new position, in this case downwards.

Human tolerance to vertical phorias are poor. With such a substantial deviation of 6Δ prism diopters, binocular vision is difficult to achieve. This explains the lack of depth judgement in treading needles. His brain has to constantly coordinate the six extra-ocular muscles (image 3) to keep the eyes vertically levelled to maintain fusion. This excessive and consistent muscle contractions are exhausting and when the muscles cannot continue to contract further, the patient adopted an abnormal head posture to lessen the muscle contraction and exhaustion, as this allowed the 2 retinal images to be fused easier.

To treat his hypophoria, I prescribed prisms into his spectacles. How the prisms work in general has been described in other cases before (see images 4a, 4b). The prisms hugely reduced his exhaustion and lets see if his binocular vision can improve next year. Otherwise, some binocular vision exercises may be required. My job is done.... for the time being. 😃

(to be continued)

28/07/2025

Always nice to be appreciated.... Thank you for your kind words 🥰

27/07/2025

26/07/2025

Celebrating my 10th year on Facebook. Thank you for your continuing support. I could never have made it without you. 🙏🤗🎉

25/03/2025

This 13 year old patient visited me for an eye exam today (image 1). He has congenital nystagmus and has been in my care since 6 years old. I have previously written about him:
https://www.facebook.com/behoptometryclinic/posts/pfbid033AfHev8u7G1Z4eAsNxZL8VYeuyLpfhnspuaJX6FLrs9bqDWpLFAispD6rf5S4jnrl

On a healthy retina, the highest concentration of cones resides on the macula (image 2a, 2b). Cones are light sensitive nerve cells that detects the smallest details of the image focused on the retina and they are also responsible for colour vision. An estimated 6 to 7 million cones can be found on the macula.

Congenital Nystagmus is a condition where the retina is underdeveloped and there is no functional macula. There are a number of causes of retina under-development but in this patient it is due to complications and lack of oxygen to the infant during birth.

When we look at an object, our eye will move so that the retinal image of that object is focused on the macula. This allows us to see the object clearly and is called fixation. However, when the macula is under- or undeveloped, the brain will keep moving the eye to find the best region of the retina to place the image on for the patient to see the clearest. So the eye will oscillate and this happens in nystagmus (images 3a, 3b).

Despite starting off with under-developed retinae (plural, singular: retina), years of wearing correctly prescribed spectacles seems to have forced his retinae to partially develop and organised itself so his acuity has improved, from 6/36 to 6/18 (third line to fifth line). His parents were naturally overjoyed with this news.

Every retina is precious and we do not give up. My mission continues... 💪