Our world is often filled with light, from dawn to dusk and beyond. Many cannot imagine a life which has no light. Yet, some of those around us are unable to perceive light and face a life of darkness.

As we mark World Glaucoma Week from March 6-12, I would like to share what it is like treating those with night blindness, cataract and glaucoma as well as a story about a patient of mine at the National University Hospital.

HOW TO TEST FOR NIGHT BLINDNESS

In my younger days as a trainee eye doctor, I was tasked with taking patients who were suspected of having night blindness to perform the Electroretinogram (ERG) test.

This required them to sit in total darkness to prepare their retina for the test. It usually takes about half an hour for the retina to adapt properly to the darkness and during this period, I would be sitting there too.

If you have ever been stuck in a lift that has broken down and lost power, it feels a lot like that. You might actually be grateful for some company, and inevitably, you will strike up a conversation with the other party.

In the ERG room, I would usually talk to my patient, and those listening skills I had to hone way back definitely came in handy.

Night blindness, or retinitis pigmentosa, is an inherited condition where there is a breakdown and loss of cells in the retina — the light sensitive tissue that lines the back of the eye.

This causes the vision to be poorer in the periphery and in dim lighting.

Patients with night blindness may have difficulty moving around safely as their peripheral (side) vision may be lost, especially at night.

About one in 4,000 suffers from it and it manifests as an increasing inability to see in darker conditions, progressing to tunnel vision and finally potential total loss of vision.

However, not everyone will reach this stage. There are people with milder conditions who can retain some vision.

It is important to get assessed by an eye doctor, using an ERG test, and for them to perform visual field perimetry tests as well as genetic testing.

Getting a proper evaluation is critical as these patients may also develop glaucoma and cataracts.

The degree to which a person is affected by night blindness is variable, just like the speed of progression and severity.

As there is no immediate treatment for the condition, we usually advise patients to continue to live with it and use the time to live well.

In the meantime, ophthalmologists can help to treat any associated illnesses such as glaucoma and cataract.

By treating these conditions early, doctors can help patients retain some vision till the later stages of their lives and allow them to live some semblance of a normal life.

THE TEACHER LOOKING AT HIS FINAL SUNSET

Let me move on to the patient I mentioned at the start of this piece.

He is a middle-aged man who had gradually found it difficult to see properly at night.

Initially, he had just brushed it aside as he was quite myopic, but it began to affect his work as a teacher so he decided to seek help.

After the initial consultation, he was booked for an ERG test, and it so happened that his appointment was on the day I was rostered to sit in the darkness.

As usual, we struck up a conversation. It was a strange thing, to sit in the dark and suddenly a voice floats in the air, with no form that you can visualise and it feels a little out of body.

I could also hear the most minute sounds, such as the sound of the clock ticking, or even the faint sounds of the hospital trolleys creaking away as they pass the doors of the ERG lab.

The patient was an active chap, with a life that was filled with a variety of co-curricular activities. He was also looking forward to doing something active during his term holidays with his family.

I felt a chill as I looked at his results and saw the tell-tale changes which indicated retinitis pigmentosa.

The results were confirmed later on and we spent a great deal of time explaining it to him and his spouse. Thankfully, whilst he did have the disease, it was a milder form.

Initially, the man was devastated, but as he was also a learned man, he went on a journey to find out more.

As his symptoms were quite mild at the time, he was able to continue with his job. I then lost touch with him as I continued on my training in ophthalmology.

It so happened that a few years back, he was referred to see me in my glaucoma clinic. He recalled that experience of sitting in the dark with me somehow, and greeted me even before I could recognise who he was.

This time he looked a bit more despondent than before and talked about seeing his last sunset, even though he was not much older than I was.

His vision had deteriorated, and he had assumed that his deterioration was just part of the inexorable progress of the disease.

Upon examining him, I discovered that apart from his retinitis pigmentosa, he also had glaucoma and some cataracts.

These are common associations with retinitis pigmentosa and the important thing was that with treatment, his vision could improve and he could maintain a significant part of his lifestyle.

The prevalence of primary open-angle glaucoma with retinitis pigmentosa ranges from 2 to 12 per cent.

I spent some time explaining these conditions to the patient and the various treatment options that can help him continue with his current lifestyle.

I started him on glaucoma medication to lower his eye pressure, and we also planned for cataract surgery to help with his vision.

We eventually decided on performing a combined cataract surgery with a micro-invasive implant to help lower his eye pressure at the same time.

This consists of a couple of very tiny titanium glaucoma drainage implants inserted into the eyes to help channel the aqueous humour (watery fluid) out of his eye, thereby lowering the eye pressure.

It has been a couple of years since he had the implants; his objective vision remains very good, and he is medication free for his glaucoma.

He requires more lighting at night to see, and does not drive as his contrast perception is lower, but he is far from losing his vision.

He has made it a running joke and a point to remind me that he is still enjoying his sunsets.

Whilst some diseases appear to have poor outcomes, modern medicine has allowed us to detect and determine how severe the disease is, and whether there are any associated conditions.

We then treat as many of the conditions as we can, to help patients retain as much of their vision as possible.

Each time I see a wonderful sunset, I would also think about this patient and how helping him keep his daily appointment with this wonderful time of the day also makes my day.

 

ABOUT THE AUTHOR:

Dr Loon Seng Chee is head of glaucoma and a senior consultant at the Department of Ophthalmology, National University Hospital.