Diseases affecting va

[LandLord]

A refraction cannot detect eye diseases. We all know that. But, how many diseases and disorders ARE there, that can affect visual acuity? I know of 4.

Glaucoma
Macular degeneration
Cataracts
Corneal ulcer

Is that it?

[walleye]

There are literally hundreds of disorders affecting visual acuity. ie. hypertensive retinopathy, corneal degenerations, diabetic retinopathy,etc. A great web site you can google is Red Atlas and this will show you many details of innumerable eye disorders.

[LandLord]

Thanks I will check out that website.

Also, would you happen to know how many of those disorders are symptomatic?

[fjpod]

There are hundreds if not thousands of ocular disorders that can affect VA. Sometimes a change in refraction is a "first sign" that something is wrong...but not always. Even something seemingly as harmless as superficial punctate keratitis can cause a change in VA and refraction.

As far as symptoms go, if the person has a disease that causes a reduction in VA, that is often the first symptom.

[LandLord]

So its hard to know when a change in refraction is caused by a disorder like SPK, a disease like macular degeneration, or simply a normal refraction change.

[fjpod]

No, I didn't say that. It is generally easy to differentiate if you are trained in how to perform a complete eye examination.

[LandLord]

No, I didn't say that. It is generally easy to differentiate if you are trained in how to perform a complete eye examination.

I am definitely not trained as you are. How do you know if the change is normal or pathological?

[rbaker]

I am definitely not trained as you are. How do you know if the change is normal or pathological?

You get an undergraduate degree in an appropriate field and then complete graduate education to become an optometrist or ophthalmologist. In the meantime don't be too concerned with all of this stuff . . . refer, refer, refer !

[LandLord]

You get an undergraduate degree in an appropriate field and then complete graduate education to become an optometrist or ophthalmologist. In the meantime don't be too concerned with all of this stuff . . . refer, refer, refer !

If it's all the same to you, I'd like to know.

I'm not trying to become an optometrist. I just want to know how you can distinguish between a normal refraction change and a pathological one. Can anyone answer that?

[obxeyeguy]

My guess is they trust their judgement and experience. When I worked with an OMD years ago, we had a patient that came back a couple months after his exam complaining of poor vision. All the symptoms mimicked those of an advancing cataract, as the chart indicated, and to me made perfect sense. The OMD I worked for concurred to a degree, but sent him for a blood test to check the sugar levels. Turns out, they were sky high, patient admitted to the hospital, with no previous BS problems o0r history.

She taught me at that point to not just think eyes, but to think whole body. So, my answer is as I started, it's their judgement and experience. I don't think there is some majic wand they can wave to help them out, but like us with glasses, they feel it.

[npdr]

If it's all the same to you, I'd like to know.

I'm not trying to become an optometrist. I just want to know how you can distinguish between a normal refraction change and a pathological one. Can anyone answer that?

Use a pinhole.

[Oedema]

If it's all the same to you, I'd like to know.

I'm not trying to become an optometrist. I just want to know how you can distinguish between a normal refraction change and a pathological one. Can anyone answer that?

Well, first step is to actually look at the eye for any changes that correlate with the change in refractive error or acuity, if you can rule that out, and any other funny stuff that might not show in the eye (based on patients systemic history, symptoms, perhaps a limited physical exam) then you're looking at simple refractive error change.

[fjpod]

There is no simple cookbook or flow chart approach. I'm not trying to be a smart alek and say become an optometrist, but each case is different. Yes there is a lot of repitition, but I don't think it is possible to narrow things down to say, the 6 most common causes of an Rx change. Or if a patient has symptoms of decreased VA, the 6 most likely things are... It really takes a lot of differential diagnosing.

I've seen patients with every pain and symptom under the sun and they have nothing more than a normal refractive error shift, and I have seen patients with virtually no symptoms other than a slight change in VA and it turns out they have diabetes or a brain tumor.

In order to determine why someone has had a change in refractive error, you have to know many things about that person's total
physical (and in some cases, mental) well being.

Someone mentioned a pinhole test. This will only really tell you if an optical correction is possible vs not possible. The assumption being made that if the patient sees better through the pinhole, then they are pathology free and vice versa. But this is not always true either. A diabetic with sudden onset may have a myopic shift, and a pinhole test will show improvement, but to assume that this patient is pathology free would be a disaster.

Beware of simple solutions. Perhaps some CE courses on this topic would help you along. That's how I keep on top of things like this.

[LandLord]

I feel much more enlightened now. Thanks for all your answers.

I like the pinhole test and understand its limitations.

If nothing else, at least the opticians that are refracting can use the pinhole to eliminate some candidates.

[Oedema]

fIf nothing else, at least the opticians that are refracting can use the pinhole to eliminate some candidates.

IMHO pinhole is not that useful as it will give you an idea of near-potential VA, just like an exhaustive refraction would. It still misses all the pathology that is still possible in a 20/20 eye. That and patient almost never "get it."

[npdr]

To elaborate, the pinhole is the principal and easiest means of differentiating poor vision due to potential pathology from refractive. If done often enough, the operator can create their own scale of suspicion surrounding the results. However, it is best done in the hands of a knowledgeable and trained professional because the pinhole gives varying results on occasion.

[npdr]

Oedema,

Let's not mislead or bias our answers. The Pinhole is the first result that ophthalmologists or optometrists will ask anybody else when unsatisfactory visual acuity is obtained. We might not know the true etiology of the decreased visual acuity, but we can be sure it is not refractive.

The key is the threshold value for distinguishing the results. Does a pinhole vision of 20/40 mean that there is pathology? Probably not, but it should be a threshold point for referring. Does a pinhole of 20/400 mean something. Definitely yes. It is a continuum and each operator has to interpret the pinhole tests accordingly.

[LandLord]

Personally, I didn't choose the current BC changes but if I have a choice between selling glasses until I'm out of a job, OR, changing to stay in the field, I will change.
OD's may say "opticians should not refract independendtly" but they will anyway.
Having said that, how can opticians and optometrists, both change their ways to create a better system that benefits patients and practitioners? While we're at it, why don't we design the system to encourage collaboration instead of competition between the 2 O's?
Is it even possible?

[hcjilson]

Having said that, how can opticians and optometrists, both change their ways to create a better system that benefits patients and practitioners? While we're at it, why don't we design the system to encourage collaboration instead of competition between the 2 O's?
Is it even possible?

The answer is a resounding YES.....but only with education. Obviously people can learn to refract. Most Ophthalmology practices employ techs to do it. We have three in the office where I have an independent dispensary.They are very good at it, with very little specialized education. I proper course in refractometry would include the recognition of pathology and the need to refer, refer, refer....I think in the long run it is inevitable (opticians refracting).......it is done all the time in Europe.

[Jacqui]

In order to determine why someone has had a change in refractive error, you have to know many things about that person's total
physical (and in some cases, mental) well being.
.

I'm glad someone brought up mental condition as a possibility. I've seen some of this around the Veterans Hospitals. Also don't forget Rx medications and HIV as posibilities.

[Yeap]

always treat your patient not their eye, especially for those who has systemic disease like diabetes will further affect their vision. agreed with npdr using a pin hole will tell you more about their vision status and how far it can be corrected.