Ophthalmology 29
Floaters and flashes:
the signs of acute posterior
vitreous detachment
Acute posterior vitreous detachment is a common cause of unilateral floaters and flashing
lights. These visual experiences are frightening for the patient, and in an eye examination
the physical findings are usually few and often subtle. It is a condition that frequently
occurs in the older population. Drs Chintan Sanghvi, Sarita Bhat and Jason Raw discuss its
pathophysiology and management.
DR CHINTAN SANGHVI is a specialist registrar in Ophthalmology
and DR SARITA BHAT is a specialist registrar in Geriatric/General
Medicine at the Northwest Deanery; DR JASON RAW is a consultant
geriatrician at Pennine Acute Hospitals NHS Trust, Fairfield General
Hospital
P
osterior vitreous detachment (PVD) is an
age-related degeneration of the vitreous jelly
commonly found in older people1 and in an
autopsy study, was found in 63 per cent of patients
older than 70 2 . Studies have demonstrated a clear
increase in prevalence of PVD with age and certain
studies have reported a prevalence rate varying
from 57 per cent to 86 per cent in the ninth
decade3,4. However, one should not presume PVD is
inevitable with ageing as in a significant proportion
of people the vitreous remains attached. It is found
at an earlier age in myopic eyes as they are
associated with increased liquefaction of the
vitreous body.
The relationship between the degree of myopia
and the age of onset appears to be directly related
as the higher the degree of myopia, the earlier is the
onset of PVD5. The normal ageing process the
vitreous gel undergoes to result in a PVD is
accelerated by trauma, cataract or intraocular
surgery, YAG capsulotomy, intraocular
inflammation, diabetes, vitreous haemorrhage and
certain hereditary conditions6. A recent study has
postulated that the high oestrogen levels seen in
premenopausal women may protect against PVD
and that hormonal changes in menopause may lead
to changes in the vitreous, predisposing PVD7.
Pathophysiology
The vitreous is a clear mass that makes up 80 per
Figure 1: Slit lamp image of complete Weiss ring suspended in
the vitreous in front of the optic disc
cent of the volume of the globe and occupies the
posterior cavity of the eye between the lens and
retina. It has the physical and chemical properties
of a hydrogel, being composed mostly of water, and
its molecular structure is made up of collagen and
sodium hyaluronate. These elements interact in a
manner that keeps the vitreous in a stable gel state8.
Ageing is accompanied by the formation of
liquid fi lled pockets in the gel. These enlarge and
become confluent. Some of these eyes develop a
hole in the degenerated cortical vitreous that
september 2007 / midlife and beyond / geriatric medicine
30 Ophthalmology
overlies the retina. The collected fluid in the
cavities empties into the space between the vitreous
and the retina forcibly detaches the posterior
vitreous surface from the neural retina. The
remaining solid vitreous gel collapses creating
disturbing symptoms in the form of suddenly
appearing floaters and the accompanying vitreous
traction on the retina produces the sensation of
flashing lights also called photopsiae9.
In normal eyes the peripheral vitreous is
loosely attached to the innermost lining of the
retina called the internal limiting membrane (ILM)
and strong adhesions only occur at the vitreous
base and around the optic disc. The detached
vitreous attachment to the optic disc typically
appears as a donut-shaped opacity in the vitreous
and is known as a Weiss ring (see Figure 1). The
collapse of the vitreous gel in a PVD in these eyes
is not associated with untoward sequelae. In eyes
with areas of certain types of peripheral retinal
degenerations, abnormally strong adhesions may
occur between the vitreous and the retina and
during PVD vitreous traction on these adherent
areas may result in a retinal tear. If unchecked by
prophylactic retinal laser treatment, this may
progress to a full retinal detachment,
ie a break of the neural retina from the retinal
pigment epithelium10.
Signs and symptoms
PVD is heralded by a sudden onset of flashing
lights, usually oriented vertically in the temporal
field of vision, and one or more new floaters. The
process is painless. The luminous flashes are
exacerbated by rapid eye movement. Patients may
experience one large floater, which can be
distracting when it comes in their line of sight —
or may describe spiders, fl ies, cobwebs or rings
moving around in their visual field. Movement of
the eye stirs the vitreous so that the suspended
debris move correspondingly. Vitreous floaters are
most apparent when there is a uniform
background illumination, such as a white wall.
Floaters typically become less bothersome over a
period of weeks to months as they settle below the
line of sight or the brain adapts to them.
Numerous floaters or decreased vision
accompanying the aforementioned symptoms of
an uncomplicated PVD are indicative of a more
serious problem. Numerous or ‘too many to count’
floaters suggest red blood cells from an avulsed
retinal blood vessel or pigment granules from the
retinal pigment epithelium are present in the
geriatric medicine / midlife and beyond / september 2007
vitreous. A sudden decrease of vision along with
the flashes and floaters, or a veil or curtain that
obstructs all or part of the vision is indicative of a
retinal detachment. These symptoms may
not only occur concurrently but can manifest at
any time after the onset of PVD. Thus all patients
should be encouraged to seek urgent medical
attention if they develop these problems after an
uncomplicated PVD.
Complications
Symptoms that may indicate a more serious
problem include:
> Sudden decrease of vision along with flashes and
floaters;
> A veil or curtain that obstructs all or part of the
vision;
> A sudden increase in the number of floaters.
Although the majority of patients with acute PVD
develop no complications, sight threatening
sequelae, such as retinal breaks and vitreous or
retinal haemorrhages, may occur11. Retinal
detachment (RD) can result from retinal breaks
caused by PVD; 10–15 per cent of all patients with
acute symptomatic PVD have at least one retinal
break. The incidence of breaks is higher in myopic
eyes as they have pathologically thin retinal tissue
and a greater occurrence of peripheral retinal
degeneration and diffuse chorioretinal atrophy.
In patients with acute PVD and vitreous
haemorrhage the incidence of retinal tears
increases to 70 per cent12 .
Management
Clinical history apart from age should include
onset, myopia (monocular or binocular), recent
trauma or cataract surgery. Apart from the history
of presenting symptoms and past ophthalmic
history, it is also important to note the past medical
history of the patient. Various systemic conditions
may predispose the patient to vitreous haemorrhage
(eg, diabetes mellitus, sickle cell disease and
vasculitis) or retinal breaks (eg, Stickler syndrome).
There are no medications or eye drops to make the
floaters disappear. Patients with unilateral flashes
and floaters require prompt referral to an
ophthalmologist and a complete ocular assessment
that includes measurement of visual acuity,
pupillary examination, confrontation fields, slit
lamp examination of the anterior segment and
vitreous, and dilated fundus examination using an
indirect ophthalmoscope with scleral indentation.
Ophthalmology 31
Key points
References
• Two factors that have been found to be important
in determining the onset of PVD in a healthy
person include age and refractive error.
1. Hayreh SS, Jonas B. Posterior
vitreous detachment: clinical
correlations. Ophthalmologica
2004; 218(5): 333–43
2. Foos RY, Wheeler NC.
Vitreoretinal juncture;
Snnchisis senilis and posterior
vitreous detachment.
Ophthalmology 1982; 89:
1502
3. Akiba J. Prevalence of
posterior vitreous detachment
in high myopia. Ophthalmology
1993; 100: 1384–8
4. Weber-Krause B, Eckardt C.
[Incidence of posterior vitreous
detachment in the elderly].
Ophthalmologe 1997; 94:
619–23
5. Yonemoto J, Ideta H, Sasaki K,
et al. The age of onset of
posterior vitreous detachment.
Graefes Arch Clin Exp
Ophthalmol 1994; 232: 67–70
6. Jakobiec A. Principles and
Practice of Ophthalmology W.
B. Saunders Company
Philadelphia Chapter 97 Retinal
Detachment: 1084–89
7. Chuo JY, Lee TY, Hollands H,
et al. Risk factors for posterior
vitreous detachment: a case-
• PVD is not an inevitable part of the ageing
process.
• The signs and symptoms include sudden onset of
floaters and flashing lights in the peripheral vision,
and the process is painless.
• Complications include retinal breaks, retinal
tears, retinal detachment, vitreous haemorrhage
and visual loss. Referral to an ophthalmologist is
therefore imperative.
• No medications and/or eye drops can treat
floaters and, although annoying, they usually tend
to settle. However, patient education regarding
the potential complications cannot be stressed
enough.
Scleral indentation enhances visualisation of the
peripheral retina. It involves the use of an indentor,
which is used to exert gentle pressure on the globe
through the eyelids. This creates a mound of
peripheral retina that can be observed by indirect
ophthalmoscopy. When properly done, it is well
tolerated by most patients. A prompt and
conscientious vitreoretinal examination of patients
who experience flashes and floaters, combined with
expeditious treatment of any retinal tears, provides
the most effective known means of preventing
retinal detachment secondary to a retinal break13.
Counselling
Most patients need reassurance and an explanation
regarding the nature of the floaters. Floaters are
annoying and can interfere with day-to-day
activities but are essentially benign and should
settle after a few months. However, awareness of
potential complications is a must and therefore all
patients should be educated about the symptoms of
PVD and retinal detachment, and instructed to
seek ophthalmic evaluation promptly if they have a
significant increase in floaters, loss of visual field
or decrease in visual acuity. Patients also need
to know it is an age-related process that is very
likely to occur in the other eye as well and
the fellow eye needs examination as well when
it occurs.
8.
9.
10.
11.
12.
13.
control study. Am J
Ophthalmolog 2006. Dec;
142(6): 931–7.
Adler Physiology of the eye
clinical Application Eighth
edition
Kanski Clinical Ophthalmology
fourth edition Burtterworth
Heinemann Chapter 9 Retinal
Detachment: 354–94
Kanski, Milewski, Damato,
Tanner Diseases of the ocular
fundus Elsevier Mosby
Edinburgh Chapter 6 Retinal
detachment: 220–80
Novak MA, Welch RB.
Complications of acute
symptomatic posterior vitreous
detachment. Am J
Ophthalmology 1984; 97(3):
308–14
Jaffe N. Complications of
acute posterior vitreous
detachment.Arch of
Ophthalmology 1968; 79: 568
Byer NE. Natural history of
posterior vitreous detachment
with early management as the
premier line of defence against
retinal detachment.
Ophthalmology 1994; 101(9):
1503–13
Conclusion
Posterior vitreous detachment is a common
occurrence among the older population and in the
majority of patients does not lead to sightthreatening complications. It represents a
significant event to the eye with respect to the risk
of development of retinal tears. In order to identify
and appropriately treat the small number of
patients whose PVD may be complicated by a
retinal tear or a vitreous haemorrhage, all patients
presenting with symptoms of unilateral flashing
lights and floaters should be referred for a prompt
ophthalmic evaluation as it may allow timely
intervention of PVD-related complications before
vision loss can occur.
Conflict of interest: none declared.
Acknowledgement: The authors would like to
thank the Clinical Imaging Department at the
Manchester Royal Eye Hospital for their help in
obtaining the image of a posterior vitreous
detachment.
september 2007 / midlife and beyond / geriatric medicine