Retinal Detachment

Sunir J. Garg


BASICS


DESCRIPTION


• A rhegmatogenous retinal detachment (RRD) occurs as a result of a retinal break or tear that allows fluid to enter the subretinal space and separate the retina from the underlying retinal pigment epithelium (RPE).


• It is the most common type of RD.


EPIDEMIOLOGY


Incidence


• 12 cases per 100,000 population annually in the USA


• Varies amongst different ethnicities from 4 to 12 cases per 100,000


• Appears to be more common in males than in females, and in persons aged 40–70 years


Prevalence


45 cases per 15,000 population or 0.3% in the USA


RISK FACTORS


• Axial myopia


• Lattice degeneration


• Aphakia or pseudophakia


• Prior intraocular surgery


• RRD in the fellow eye


• Trauma


• Family history of a RD


• Familial conditions:


– Stickler syndrome, Marfan’s syndrome, homocystinuria and Ehlers–Danlos


• Inflammatory or infectious conditions:


– Pars planitis


– Acute retinal necrosis syndrome


– Cytomegalovirus retinitis in AIDS patients


– Ocular toxoplasmosis


Genetics


No specific genetic mutations have been associated with a RRD.


GENERAL PREVENTION


• Controversy exists over prophylactically treating asymptomatic retinal tears and/or lattice degeneration, which may predispose one to a RRD, with laser photocoagulation or cryotherapy reduces the risk of RD formation.


– An asymptomatic patient with lattice degeneration has a low risk of a RD and may be observed without treatment (1)[A].


– A myopic, pseudophakic patient with lattice degeneration with a history of a RRD in the fellow eye should strongly be considered for prophylactic treatment.


PATHOPHYSIOLOGY


• Vitreoretinal traction is responsible for a RRD. With aging, the vitreous liquefies, and a posterior vitreous detachment (PVD) often occurs. A PVD usually occurs without complication. Occasionally, strong vitreoretinal adhesions are present and the occurrence of a PVD can lead to a retinal break.


• A retinal break allows vitreous fluid to enter through it, separating the retina from the RPE.


ETIOLOGY


• Retinal breaks are not uncommon. They typically occur with greater frequency in patients with myopia, ocular trauma, developmental or degenerative retinal abnormalities, and pseudophakic patients.


• Certain conditions may predispose one to the formation of a premature PVD (e.g., trauma) and potentiate the formation of a retinal tear.


COMMONLY ASSOCIATED CONDITIONS


• Myopia


• Lattice degeneration


• Stickler syndrome


• Marfan syndrome


• Homocystinuria


• Ehlers–Danlos


DIAGNOSIS


HISTORY


• Flashes and floaters:


– Patients with retinal tears or breaks may notice flashes and floaters.


– Small, peripheral RDs may be asymptomatic or present only with flashes and floaters.


• Visual field defect:


– A progressive loss of visual field is a common complaint. May progress to a loss of central vision as subretinal fluid encroaches into the macula. A description of a dark shadow or curtain blocking the vision may be given.


PHYSICAL EXAM


• Acute RD:


– Retinal tear or break, horseshoe tear:


– Horseshoe, or flap, tear


– A small, pinpoint hole may be found at the vitreous base with pseudophakic RDs


– Of all RRDs, 50% have more than one break


– Of all breaks, 60% are located in the upper temporal quadrant, 15% in the upper nasal quadrant, 15% in the lower temporal quadrant and 10% in the lower nasal quadrant.


– Loss of retinal transparency, convex, corrugated appearance


– The RD may undulate with eye movement


– Cell and flare in the anterior chamber


– Pigmented granules in the vitreous (tobacco dusting or Shaffer sign)


– The intraocular pressure is usually lower in the eye with a RD compared to the fellow eye; however, infrequently, it may be higher.


• Chronic RD:


– May appear transparent


– May not undulate with eye movement


– Intraretinal cysts, subretinal fibrosis, and demarcation lines are common findings.


– A demarcation line of linear pigment may be deposited at the junction of attached and detached retina.


– Anterior uveitis, rubeosis iridis, cataract, retinal neovascularization


DIAGNOSTIC TESTS & INTERPRETATION


Imaging


Initial approach

• Ultrasonography:


– A-scan ultrasound:


– Retinal tissue will show a large spike


– B-scan ultrasound:


Helpful if media opacity precludes a complete ophthalmoscopic exam


Follow-up & special considerations

• Fluorescein angiography (FA):


– Helpful in diagnosing cystoid macular edema, which may be a complication during the postoperative course of surgery.


• Optical coherence tomography (OCT):


– Helpful in revealing subretinal fluid. Especially beneficial in eyes with complete retinal reattachment but incomplete visual acuity recovery.


• Electroretinogram (ERG):


– ERG is useful in differentiating a RD from a thickened posterior hyaloid. If the retina is intact, an ERG signal should be obtained.


Diagnostic Procedures/Other


• Slit lamp exam to detect anterior uveitis, cataract, or vitreous pigmented granules


• Indirect ophthalmoscopy with scleral depression for examining the retina for a RD or retinal tear


• Contact lens examination in conjunction with slit lamp exam for small peripheral retinal breaks


Pathological Findings


• With an acute RD, as the neurosensory retina separates from the RPE, the photoreceptors are separated from their choroidal blood supply. This can lead to degeneration of the photoreceptor outer segments. With successful reattachment surgery, these outer segments may reform.


• With a chronic RD, the photoreceptor layer becomes atrophic. Furthermore, intraretinal cysts and with subretinal fibrosis may form.


DIFFERENTIAL DIAGNOSIS


• Senile retinoschisis


• Serous (exudative) RD


• Tractional RD


• Choroidal detachment


• Acute retinal necrosis


TREATMENT


ADDITIONAL TREATMENT


Issues for Referral


Vitreoretinal specialist – laser and surgical treatment


SURGERY/OTHER PROCEDURES


The goal of surgery is to approximate and seal all the breaks. Closure of the breaks occurs with bringing the edges of the tear into contact with the underlying RPE and then sealing it. Approximating the 2 edges may be accomplished by pushing the detached retina toward the eye wall (pneumatic retinopexy, or vitrectomy) or bringing the eye wall closer to the detached retina (scleral buckle). Sealing of the breaks is then accomplished by creating adhesions between the choroid and detached retina (laser photocoagulation, cryotherapy).


• Laser photocoagulation:


– May be used to prevent the progression of the detachment by creating a “scarred” barrier with laser burns.


– Limited in that photocoagulation cannot seal a retinal tear in the presence of subretinal fluid; therefore, it is seldom used as sole management for RD.


• Cryotherapy:


– May be used alone, or in conjunction with another repair modality, in treating a break with shallow subretinal fluid around it.


– Limited in cases where large amount of subretinal fluid is present.


• Pneumatic retinopexy:


– Greatest benefit in a phakic patient with a single, superior retinal break, and without other retinal pathology.


– The retinal break is tamponaded with an intravitreal gas bubble.


– After resolution of the subretinal fluid, either laser photocoagulation or cryotherapy may be applied to seal the break.


• Scleral buckle:


– A flexible silicone band or sponge is permanently sutured onto the sclera, indenting it, to relieve vitreoretinal traction on the retinal break.


– Cryotherapy or photocoagulation may then be applied.


– Injection of intravitreal gas may also be used.


– Success rates of 95% may be achieved.


• Vitrectomy (2):


– Especially useful for RDs with posterior breaks, proliferative vitreoretinopathy, or vitreous hemorrhage.


– Common technique used for primary RD with or without a scleral buckle.


– Mechanism allows for a direct release of vitreoretinal traction.


– Intravitreal gas or silicone oil may be used to tamponade the retina in addition to the application of cryotherapy or photocoagulation.


IN-PATIENT CONSIDERATIONS


Initial Stabilization

Prior to reattachment surgery for a RRD, patients should rest as much as possible.


Admission Criteria


Most vitreoretinal surgery is performed on an outpatient basis.


ONGOING CARE


FOLLOW-UP RECOMMENDATIONS


• Following surgical retinal repair, the patient will be instructed to maintain a certain head position for several days following surgery.


• Following surgery, a topical antibiotic is given for 7–10 days, a topical steroid for 1 month, and a cycloplegic agent for 1 month.


• The intraocular pressure is monitored during the postoperative course.


PATIENT EDUCATION


• Provide a patient with a PVD or risk factors for a RD with warning signs of flashes and floaters.


• Warn the patient of the risk of a RD in the fellow eye if one eye has experienced a RRD.


– Up to 10–15% in phakic eyes


– Up to 25–40% in aphakic or pseudophakic eyes


• If performing cataract surgery or YAG capsulotomy, warn the patient of the risk of a RD.


PROGNOSIS


• Most RDs, if left untreated, progress causing permanent deterioration of central vision. The final visual potential is dependent on whether the macula is “off” (separated from the RPE). Once the macula is detached, the photoreceptors begin to degenerate.


– The most important factor affecting postoperative visual acuity is the preoperative visual acuity.


– If a macula “off” detachment is operated within 72 h from presentation, the patient’s visual prognosis is more favorable.


• Chronic, asymptomatic RD may not require treatment if stable.


• After successful reattachment, recovery may take months; however, central vision may never recover even with adequate treatment.


• Of the eyes that are successfully reattached, 50% obtain a final visual acuity of 20/50 or better.


COMPLICATIONS


• Proliferative vitreoretinopathy – the most common reason for surgical failure


• Cystoid macular edema


• Rubeosis iridis



REFERENCES


1. Wilkinson C. Interventions for asymptomatic retinal breaks and lattice degeneration for preventing retinal detachment. Cochrane Database Syst Rev 2005(1):CD003170.


2. Arya AV, Emerson JW, Engelbert M, et al. Surgical management of pseudophakic retinal detachments: A meta-analysis. Ophthalmology 2006;113(10):1724–1733.

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Nov 9, 2016 | Posted by in OPHTHALMOLOGY | Comments Off on Retinal Detachment

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