PECAA Practice Pearl: Things You Don’t Want to Miss
By: Paul M. Karpecki, OD, FAAO
Clinical Director – PECAA
One of the roles as medical director at PECAA is to not only educate my colleagues but also protect you from potentially missing a key diagnosis, which could have liability issues but more importantly could affect a patients vision or life. This case is an example of that.
A patient presented with decreased vision in one eye to 20/30+2. The other eye corrected to 20/20+2 and although it’s ‘been this way for awhile’ according to the patient, only recently had she compared eyes and the noticeable difference prompted her to make an eye appointment.
Although her history doesn’t sound like an ocular emergency given her lack of urgency and there could be many causes, there are some definite key tests that must be assessed and acted on if a decrease in vision is present. The following need to be performed in all cases of a painless loss of vision:
1. Visual acuity testing individually and manifest refraction to obtain best correctable vision and pinhole vision
2. Pupil testing for potential relative afferent pupillary defect (RAPD)
3. Confrontational visual fields
4. Ocular examination including slit lamp exam and dilated fundus examination
The patient’s vision in the affected eye best corrected to 20/30+2. There appeared to be a +RAPD and confrontation fields were difficult in that eye. Based on that alone, further testing was required. As a clinician, you must have a solid reason for any vision that is not correctable to 20/20 or better (amblyopia is a diagnosis of exclusion and must be supported by high refractive error, anisometropia or strabismus).
The next course of testing should include:
1. Color vision testing (preferable with more advanced tests than Ishihara plates – a good example is the new ColorDx CCT-HD from Konan Medical)
2. More advanced or sensitive pupil testing such as EyeKinetix is more accurate than a swinging flashlight test
3. An automated visual field test
Results showed a deep depression on the visual field test only in that eye, a positive grade 2 RAPD, and color vision deficiencies. Slit lamp and fundus examinations showed no pathology however.
Referral to a neurologist or neuroophthalmologist and/or ordering orbital and brain imaging (MRI) should be performed promptly.
The patient was diagnosed with a meningioma. The point of this case is to know the key tests that help you make a crucial diagnosis. To know that amblyopia must be explained by some reason for it such as extreme refractive error or strabismus. Remember in a pointless loss of vision to test VA (including best corrected and pinhole) but also pupils, color vision and visual fields. These findings prompted the referral and ultimate diagnosis.