Guidelines for helping you manage patients who have flashes and floaters; also, when to make a referral.
Patients who don't need surgery don't need a referral to a surgeon. Interestingly, however, practitioners refer many patients to the vitreo-retinal surgeon's office without a surgical need. One category of patient that practitioners often refer consists of individuals who experience flashes and floaters without having a retinal tear or retinal detachment that requires immediate photopexy or cryopexy.
Consider that eyecare practitioners find retinal breaks (atrophic holes and retinal tears) in 5% to 10% of the population, but that rhegmatogenous retinal detachments (RRD) only occur at a rate of one in 9,000 to one in 20,000 each year in the general population. Virtually all patients will experience floater formation as vitreous liquefaction (syneresis) occurs with age and many will have brief episodes of flashes (photopsia). This leaves a large number of patients who don't need surgery and consequently creates a tremendous practice growth opportunity.
Examining and following patients who have typical floater formation is within the education and training of the optometric physician. This article will review how to approach the patient who has acute symptoms of vitreous floaters and photopsia.
First things first
When a patient who fits the above description presents to your office, begin by eliciting a chief complaint of floaters, flashes or both. Check distance visual acuities with the patient's habitual prescription and measure pinhole acuities if he has a decrease in vision. Test pupils, motilities and confrontation visual fields (it takes a rather large retinal detachment to cause an afferent papillary defect).
Conduct a brief slit lamp examination to assess the angles and instill 2.5% phenylephrine (various brand names) and 1% tropicamide (Mydral, Mydriacyl, Opticyl). Doing so will save time (the patient's eyes can dilate while you obtain a thorough history of present illness [location, duration, timing, severity, quality, context and associated symptoms]). It's also necessary to conduct a review of systems to rule out other causes of vitreous hemorrhaging such as diabetes, hypertension and atherosclerosis.
Being Sherlock Holmes
Begin your assessment of the flashes/floaters patient with a thorough history. Probing with the right questions gives you an idea of the likelihood that a retinal tear or detachment is present. It can also tip you off to take another look when you don't immediately find a retinal tear.
Think of the patient as having good or bad flashes/floaters symptoms. A description of purple arcs of light in the peripheral vision - especially when walking down a dark hallway - indicates Moore's lightening streaks and typically don't signal a retinal tear.
However, when the patient reports bright flashes resembling streaks of light, lighted cobwebs or flash bulbs, these are more compatible with retinal tears and detachments.
Likewise, floaters that a patient describes as strands are consistent with the collagen from vitreous liquefaction. Floaters described as specks of pepper, blizzards, swamp water or cheesecloth vision are almost always bad and associated with a vitreous hemorrhage. A floater that looks like a big fly or spider is usually Weiss's ring and signals a posterior vitreous detachment (PVD). Patients who have undergone an uncomplicated PVD typically will describe the sudden onset of strand floaters (collagen), a big floater (Weiss's ring) and perhaps a few purple arcs of light.
Other particulars to look for in the history are the presence of high myopia, prior intraocular surgery, family history of retinal detachment and trauma. Patients may also report that a change in posture or shift in gravity (bending over) precipitated the onset of symptoms. The shift encourages the vitreous to separate from the retina and if strong vitreo-retinal traction is present, then a retinal tear can occur.
Lastly, don't forget to question the patient about peripheral vision loss. If a retinal detachment is encroaching on the macula, then the patient should see a curtain or veil in his vision. Knowing what to ask and what the various descriptions typically mean will aid you in your retinal exam.
Take another look
Next comes the retinal exam, which begins with a good slit lamp examination. When examining the patient who has retinal tears or detachment, it's critical to look for cells and flare in the anterior chamber, pigment in the anterior chamber and pigment cells or red blood cells in the anterior vitreous (Shafer's sign or tobacco dust).
Patients who have detached retinas often times will have a low-grade iritis with trace to 1+ cell. Pigment from retinal breaks can also spill over into the anterior chamber and float in the aqueous. Pigment cells and/or red blood cells in the anterior vitreous is strongly associated with a retinal tear. However, pigmentary dispersion syndrome and cataract surgery can also deposit pigment in the vitreous.
As a rule of thumb, if you notice pigment or red blood cells in the anterior vitreous and you don't see the retinal tear, then look again, because you may have missed it. Realize, of course, that a PVD can cause a retinal vessel to hemorrhage without causing a bona fide tear.
Next comes "the really bright lights." The tried-and-true standard for evaluating patients is to perform a dilated retinal exam using at least two techniques to view the retina. Retinal specialists typically will view the retina with the binocular indirect ophthalmoscope (BIO), often with scieral depression and slit lamp fundoscopy.
The technique that I have found most useful is to view the retina with high plus aspheric noncontact fundoscopic lenses through the slit lamp while the patient looks in the different directions of gaze. This viewing technique offers a sharp image with a wide field of view and excellent stereopsis. In my experience, I've been able to find retinal tears with the SuperField NC that I can't find with the BIO, even with scierai depression.
To refer or not to refer
You've examined the retina, found a lesion and you know the statistics (see "Important Statistics" on page 62 if you don't or if you need to brush up on this information). Do you follow the patient or refer him? "Guidelines for Follow Up on Retinal Tears and Atrophie Holes" (above) illustrates some guidelines for follow up versus treatment.
Fortunately, most patients present with PVD, lattice degeneration, atrophic holes or operculated holes that we can monitor and that don't require treatment.
However, if you notice extension of subretinal fluid or formation of a new retinal tear, then you need to refer the patient. A retinal hole typically won't progress to retinal detachment and you may monitor it for the first couple of months until you can document that the lesion is stable. A retinal tear (horseshoe) represents vitreoretinal traction and often can lead to retinal detachment, hence the need for prophylactic treatment.
A recent, uncomplicated PVD has the highest probability of retinal tear the first month, which is why you should re-evaluate it during this time period. Always inform patients that an increase in flashes/floaters can signal a new retinal tear or detachment and that they should return for a repeat dilated retinal exam immediately, in this event.
Resolving retinal breaks
Below are the general guidelines for treating retinal breaks.
* Asymptomatic atrophie retinal holes, lattice degeneration (with or without atrophic holes), PVD and operculated retinal holes: usually not treated, as RRD rarely occurs. You should monitor these lesions closely the first couple of months until it can be documented that they are stable, then monitor them every six to 12 months thereafter.
* Symptomatic or asymptomatic horseshoe and symptomatic operculated tears: treat these because of the high association with RRD.
Most patients with flashes and floaters don't have a horseshoe tear or retinal detachment requiring urgent treatment. Thus, these patients don't need a surgical referral. Dilated fundus examinations are within the scope of practice for optometric physicians. Remember to look and look again and if no surgical pathology exists, then monitor closely.
References available on request.
BY KEN RODDY, O.D., F.A.A.O.
Dr. Roddy is a 1986 graduate of the Oklahoma College of Optometry. He completed a post-graduate residency in ocular disease management in 1993 and has been in private practice with his wife Denise since then. Dr. Roddy does not have financial or proprietary interests in the companies or products mentioned in this article.
Copyright Boucher Communications, Inc. May 2005
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