The Routine Eye Exam
Chat Highlights
September 20, 2006

On Wednesday, September 20, 2006, Dr. Michael James Pro, a glaucoma specialist at Wills, and the glaucoma chat group discussed "The Routine Eye Exam."

Moderator: Welcome, Dr. Pro.  I understand you studied with Dr. Robert Ritch and are now a partner with Dr. Rick Wilson.

Dr. Pro:   Yes, I studied with Dr. Ritch at the New York Eye and Ear Infirmary.  He is famous for much of the early work on narrow angles and plateau iris.  I have joined Dr. Wilson's group.

Moderator:  We are glad you could join us tonight to discuss a routine eye exam.  What does that exam consist of for someone without any glaucoma history?

Dr. Pro:  That depends upon the patient's age.  Most healthy adults should have a thorough eye exam, including refraction and dilation, every five years.

P:    Five years! That seems like a long time.

Dr. Pro:  For healthy eyes, yes.  But every person needs to have his or her angles evaluated at least once.

P:  What is looked for with refraction and dilation?

Dr. Pro:  A refraction is an examination necessary for spectacle correction.  Dilation is necessary to evaluate all structures behind the iris; namely, the lens, the vitreous, the optic nerve, and the retina.

P:  How can the shallow-chambered, narrow-angle eye be identified by using a flashlight during a routine eye examination?

Dr. Pro:  The flashlight test is done by shining light from one side of the eye.  You look for a shadow on the other side.  It is not performed by any glaucoma specialist, as it is not specific. To properly evaluate the angle, the examiner needs to use a gonioprism, which is a special type of mirrored lens.

P:  Why does a doctor look for shallow-chambered, narrow angles?

Dr. Pro:  A narrow angle can lead to two problems.  One is a sudden attack of angle-closure glaucoma caused by a sudden obstruction of the angle.  The second, much more common, problem is chronic scarring of the drainage angle that eventually leads to poor drainage and secondary glaucoma.

P:  Do optometrists and ophthalmologists perform routine eye exams the same way?

Dr. Pro:  That depends upon the optometrist.  Some perform excellent routine exams, including refraction and dilation.  Optometrists are less skilled at evaluating the angle.

P:  How do you evaluate angles?

Dr. Pro:  I use the gonioprism with the slit lamp in a dim room.

P:  How often should an adult in his or her late thirties be screened for glaucoma if both parents had glaucoma?

Dr. Pro:  First, you need a complete examination, including angle evaluation and corneal thickness measurement.  Then the risk factors can be determined. If the examination is unremarkable, I would evaluate that person on a yearly or bi-yearly basis.

P:  Do you make routine use of any of the objective methods for evaluating presumptive pathology of the optic nerve, i.e., HRT, GDx, OCT?  Which of these, if any, do you think has the greatest utility in identifying initial pathology and tracking its progression?

Dr. Pro:  I use all three. In my practice, most patients have already been diagnosed with glaucoma.  So I follow change in the optic nerve with the HRT, as it is the only one with software that can do that.  But the OCT and GDX are both useful in glaucoma suspects to determine abnormalities in the optic nerve that would raise the patient's risk of developing glaucoma.

P:  What should a glaucoma patient or a glaucoma candidate insist upon during an eye exam?  Is central corneal thickness measured routinely?

Dr. Pro:  Good question.  Measurement of central corneal thickness, angle evaluation, and baseline imaging of the optic nerve are a must.

P:  Can you see the lens and nerve without dilating the pupils of someone at risk for an attack of acute-angle closure?

Dr. Pro:  Yes, but the view is generally monocular because the pupil is too small.  Often, though, you can judge the amount of glaucoma from that view.

P:  What do you mean by monocular?

Dr. Pro:  Monocular refers to my view using a single eyepiece.  The slit lamp in the examining room gives a stereo view of the eye.  Both of my eyes need a clear view.  When the pupil is small, only one of my eyes can see into the back of the eye.

P:  What is meant by "amount” of glaucoma?  Does that refer to intraocular pressure (IOP) or the damage to the optic nerve?

Dr. Pro:  It’s the amount of damage to the optic nerve and visual field loss.

P:  After the examination, do doctors tell patients if they have narrow angles?

Dr. Pro:  They should. In all cases, I tell patients of their diagnosis.  For instance, with narrow angles, drugs such as anti-histamines can precipitate an attack of acute-angle glaucoma.

P:  How can an ophthalmologist see opacities, pigment, and debris in the vitreous clearly?

Dr. Pro:  By performing a dilated eye examination.

P:  Should a glaucoma "candidate" have a visual field test?

Dr. Pro:  That’s more tricky than it sounds. In general, yes, but it’s difficult with some patients, such as children.  The test results are unreliable and lead to more concern than is warranted.

P:  I used to not have dilated eye examinations because the doctors were concerned about my having a closed-angle attack.  Is that a common risk?

Dr. Pro:  It’s rare, but it happens.  Some patients with narrow angles are diagnosed that way.

P:  What is the difference between open-angle and closed-angle glaucoma?

Dr. Pro:  Those terms refer to the way the angle looks.  The angle, between the iris and the cornea, is the part of the eye that drains the fluid (aqueous) from the eye.  “Open” means that the angle appears not to have any obstruction of fluid leaving the eye.  “Closed” means that the angle is narrow and looks like fluid may be obstructed from exiting.  Both lead to the same disease and end result, but treatment is different.

P:  What is baseline imaging?  Is it used for glaucoma suspects?

Dr. Pro:  Glaucoma suspects need a photo or digital image of the optic nerve.  It is useful for comparison later in life or with different doctors.

P:  If I have had routine, yearly eye examinations and have been told I have healthy eyes, then an examination shows my IOP is higher, say, in the 20’s, would I immediately need to begin glaucoma medications?  Or would further evaluation be needed if the eye still looks healthy?

Dr. Pro:  Of course, you would need further exams, including visual fields and, more importantly, repeated IOP measurements.  A single IOP measurement could be an aberration.

P:  What is the use of the SLO (scanning laser ophthalmoscope)?

Dr. Pro:  That is the "generic" name for the HRT (Heidelberg Retinal Tomograph), which is confocal SLO.  It can be used to make a digital map of the optic nerve and can be compared for change at serial exams.

P:  Just for the record, what should a routine eye exam include?

Dr. Pro:  A complete routine eye examination includes refraction (glasses correction), IOP (pressure check), angle evaluation, and a dilated eye examination.

P:  Is the amount of damage to the optic nerve related to "cupping"?  Can cupping be misleading? Can glaucoma be progressing, but the degree of cupping remains the same?

Dr. Pro:  Cupping refers to an arbitrary number that the examiner gives to an optic nerve. It is a ratio of "empty space" to remaining rim tissue.  So I might say that your optic nerve is a 0.8 cup to disc.  The next doctor might say it is 0.9.  Your nerve is still the same.  Subtle signs like focal loss of nerve tissue (rim) and nerve fiber layer defects need to be watched.

Moderator:  Thank you, Dr. Pro. It has been a pleasure and an honor having you join us.  We wish you well in your practice with Dr. Rick.

On October 4, Dr. Pro discussed "Visual Field Testing" in the Chat room. Click here for highlights of that meeting.

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