How is a horseshoe (flap) retinal tear best defined?

A full-thickness neurosensory break caused by vitreoretinal traction Horseshoe tears are full-thickness breaks of the neurosensory retina caused by vitreoretinal traction, with the flap apex pulled anteriorly while its base stays attached.

A partial-thickness split of the inner retinal layers

A circumferential disinsertion of retina at the ora serrata

An atrophic round hole within an area of thinned retina

What is the most common cause of a horseshoe retinal tear?

Posterior vitreous detachment Posterior vitreous detachment is the commonest cause of horseshoe tears, exerting traction that pulls a flap of retina into the vitreous cavity.

In which quadrant are horseshoe tears most commonly found?

Superotemporal Horseshoe tears occur most often in the superotemporal quadrant, followed by the superonasal quadrant.

What proportion of all phakic retinal detachments occur in myopic eyes?

42 percent Retinal break prevalence in myopes matches the general population at 11 percent, yet myopes account for 42 percent of all phakic retinal detachments.

Lattice degeneration is present in what proportion of eyes with rhegmatogenous retinal detachment?

30 percent Lattice degeneration occurs in about 5 percent of eyes overall but is found in 30 percent of all eyes with rhegmatogenous retinal detachment.

Where do flap tears typically arise in relation to an area of lattice degeneration?

At the posterior or posterior lateral margin Pronounced vitreoretinal adhesion at the lattice margin predisposes to tears after PVD, typically at the posterior or posterior lateral margin of the lesion.

In the centre of the lattice lesion

Anterior to the lattice, at the ora serrata

Directly beneath the lattice at the pigment epithelium

Blunt ocular trauma is most commonly associated with which type of retinal break?

Retinal dialysis in the superotemporal periphery Blunt trauma classically causes retinal dialysis, mainly in the superotemporal periphery, though horseshoe tears and macular holes can also result.

Giant retinal tear of the nasal periphery

Multiple atrophic holes at the posterior pole

Macular pseudohole with an epiretinal membrane

When retinopexy is performed for a horseshoe tear, what must the treatment cover?

The posterior aspect of the tear and its anterior corners Laser or cryotherapy retinopexy must surround both the posterior aspect of the tear and its anterior corners, and should be done immediately after diagnosis.

Only the flap apex within the vitreous

The entire quadrant containing the tear

A complete circumferential band at the ora serrata

What does subretinal fluid around a horseshoe tear indicate?

A coexisting retinal detachment Subretinal fluid around the tear means a retinal detachment, most often rhegmatogenous, is present and usually requires vitrectomy or scleral buckle.

Spontaneous healing of the break

Successful adhesion after retinopexy

How is subclinical retinal detachment defined in relation to a retinal break?

Fluid one disc diameter behind the break, within two beyond the equator Subclinical detachment is subretinal fluid at least one disc diameter from the posterior edge of the break, extending no more than two disc diameters beyond the equator, without visual field loss.

Any subretinal fluid touching the fovea

Fluid confined entirely within the flap of the tear

Fluid reaching the ora serrata anteriorly

Horseshoe tears: Causes, Symptoms, and Treatment

CASE REPORT

a 65-year-old man developed an abnormal vision in his left eye and presented to a hospital a few weeks after the initial presentation. Prior to this development, he had been physically well and had not had any history of ocular disease or previous injury.

On initial examination, the best-corrected visual acuity was 0.8 in the right and 0.3 in the left eye. Intraocular pressure was 15 mmHg in the right and 10 mmHg in the left eye. Light reflex was rapid in both eyes and the relative afferent pupillary defect was negative. Slit-lamp examination showed cataracts in both eyes.

Fundoscopy revealed a horseshoe-like tear on the temporal side of the macula in the left eye. The tear size was 0.75 disc diameter. There was adhesion between the retinal tear and the vitreous. Fluorescein angiography revealed a nonperfusion area and the absence of any findings of retinal vein occlusion.

Horseshoe tears DISEASE entity

Horseshoe tears, also referred to as flap or U-shaped tears, are full-thickness breaks in the neurosensory retina that occur secondary to vitreoretinal traction. The apex of the flap is pulled anteriorly into the vitreous cavity while the base remains attached to the retina.

The most common cause of a horseshoe tear is a posterior vitreous detachment (PVD). Horseshoe tears are more common in the superotemporal quadrant followed by the superonasal quadrant.

Horseshoe tears frequently occur in middle-aged individuals and no statistical difference exists between men and women in the incidence of retinal breaks.

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Horseshoe tears Risk Factors

Risk factors are:

Age: Increased incidence of retinal tears in adults is noted with increasing age.

Myopia: The prevalence of retinal breaks in myopic eyes is similar to that of eyes in the general population (11%). However, myopes account for 42% of all phakic RD and, therefore, myopia is considered a risk factor for retinal breaks that lead to RD.

Lattice Degeneration: this is a condition in which peripheral retinal thinning is associated with liquefaction and separation of the overlying vitreous. It is often related to round retinal holes, but it can also be associated with flap tears at the edge of the lattice.

There is pronounced vitreoretinal adhesion at the margin of lattice lesions, which can predispose to retinal tears after PVD. These tears typically occur at the posterior margin or posterior lateral margin of lattice degeneration. This condition occurs in 5% of eyes and is more prevalent in moderate myopia.

Lattice degeneration is found in 30% of all eyes with rhegmatogenous retinal detachments. Long-term observational studies suggest that not all cases of flap tears develop clinically significant retinal detachment.

Penetrating trauma: can increase the risk of a retinal break either immediately after impact, due to direct retinal trauma, or later on due to vitreous traction on the peripheral retina.

Blunt trauma: is more commonly associated with retinal dialysis mainly located in the super-temporal periphery, but it can also cause other types of retinal breaks, such as horseshoe tears or macular holes.

Family history of retinal tears or retinal detachment

Previous ocular surgery

MANAGEMENT of Horseshoe tears

General treatment

The decision to treat a retinal tear is based on several factors, including symptomatology, patient age and systemic health, refractive error, location, age, type, size of the break; status of the fellow eye, lens status, and family history of retinal break and/or retinal detachment.

Medical therapy

Although some ophthalmologists consider that asymptomatic horseshoe tears may not be treated, others stress that all tears require treatment by retinopexy, either laser photocoagulation or cryotherapy. Any retinopexy performed must cover both the posterior aspect of the tear and its anterior corners.

This should be performed immediately after the diagnosis, and subsequent reviews are merely to determine that the retinopexy is adequately encompassing the defect.

Surgery

Any subretinal fluid around the tear indicates that a retinal detachment (most commonly rhegmatogenous) is present, and a surgical retinal detachment procedure is usually required for clinical retinal detachments, such as pars plana vitrectomy or scleral buckle.

If the subretinal fluid is minimal, cryotherapy can sometimes be successful on its own, however, this should be done rarely and only if appropriate and the eye should be closely monitored. Most subclinical detachments can be managed by laser or cryopexy.

Subclinical retinal detachment has been defined as the subretinal fluid of at least 1 disc diameter from the posterior edge of the break but not extending more than 2-disc diameters beyond the equator which does not affect the visual field.

REFERENCES

1. Byer NE., Long-term natural history of lattice degeneration of the retina. Ophthalmology 1989;96:1396–401.

2. Kun E., Gross and microscopic pathology in autopsy eyes. Part III. Retinal breaks without detachment. Am J Ophthalmol 1961; 51:369-391.

3. Haiman M.H., Burton T.C., Brown C.K., Epidemiology of retinal detachment. Arch Ophthalmol 1982; 100:289-292.

4. Byer N.E., What happens to untreated asymptomatic retinal breaks, and are they affected by posterior vitreous detachment? Ophthalmology 1998; 105:1045-1050

5. Davis M.D.: Natural history of retinal breaks without detachment. Arch Ophthalmol 1974; 92:183-194.

6. Smiddy W.E., Flynn H.W., Nicholson D.H., et al, Results and complications in treated retinal breaks. Am J Ophthalmol 1991; 112:623-631.

Test yourself

A few questions straight from this article.

1 / 10 0 correct

How is a horseshoe (flap) retinal tear best defined?
Horseshoe tears are full-thickness breaks of the neurosensory retina caused by vitreoretinal traction, with the flap apex pulled anteriorly while its base stays attached.
What is the most common cause of a horseshoe retinal tear?
Posterior vitreous detachment is the commonest cause of horseshoe tears, exerting traction that pulls a flap of retina into the vitreous cavity.
In which quadrant are horseshoe tears most commonly found?
Horseshoe tears occur most often in the superotemporal quadrant, followed by the superonasal quadrant.
What proportion of all phakic retinal detachments occur in myopic eyes?
Retinal break prevalence in myopes matches the general population at 11 percent, yet myopes account for 42 percent of all phakic retinal detachments.
Lattice degeneration is present in what proportion of eyes with rhegmatogenous retinal detachment?
Lattice degeneration occurs in about 5 percent of eyes overall but is found in 30 percent of all eyes with rhegmatogenous retinal detachment.
Where do flap tears typically arise in relation to an area of lattice degeneration?
Pronounced vitreoretinal adhesion at the lattice margin predisposes to tears after PVD, typically at the posterior or posterior lateral margin of the lesion.
Blunt ocular trauma is most commonly associated with which type of retinal break?
Blunt trauma classically causes retinal dialysis, mainly in the superotemporal periphery, though horseshoe tears and macular holes can also result.
When retinopexy is performed for a horseshoe tear, what must the treatment cover?
Laser or cryotherapy retinopexy must surround both the posterior aspect of the tear and its anterior corners, and should be done immediately after diagnosis.
What does subretinal fluid around a horseshoe tear indicate?
Subretinal fluid around the tear means a retinal detachment, most often rhegmatogenous, is present and usually requires vitrectomy or scleral buckle.
How is subclinical retinal detachment defined in relation to a retinal break?
Subclinical detachment is subretinal fluid at least one disc diameter from the posterior edge of the break, extending no more than two disc diameters beyond the equator, without visual field loss.