Postoperative Retinal Detachment


Background

Anytime subretinal fluid accumulates in the space between the neurosensory retina and the underlying retinal pigment epithelium (RPE), a retinal detachment occurs. Depending on the mechanism of subretinal fluid accumulation, retinal detachments traditionally have been classified into rhegmatogenous, tractional, and exudative.

The term rhegmatogenous is derived from the Greek word rhegma, which means a discontinuity or a break. A rhegmatogenous retinal detachment (RRD) occurs when a tear in the retina leads to fluid accumulation with a separation of the neurosensory retina from the underlying RPE. This is the most common type of retinal detachment.

Intraocular surgery is a major risk factor in the development of RRD. Since cataract surgery is the most common intraocular procedure, it also is the most common risk factor for RRD. It has been estimated that 20-40% of RRDs occur in eyes that have undergone cataract extraction.

Pathophysiology

Vitreoretinal traction is responsible for the occurrence of RRD. As the vitreous becomes more syneretic (liquefied) with age, a posterior vitreous detachment (PVD) occurs. In most eyes, the vitreous gel separates from the retina without any sequelae. However, in certain eyes, strong vitreoretinal adhesions are present, and the occurrence of PVD can lead to a retinal tear formation. Fluid from the liquefied vitreous can seep under the tear, leading to a retinal detachment.

Aphakia and pseudophakia, especially after YAG capsulotomy, predispose to PVD. Previous studies have shown that the incidence of PVD increased with age and with duration of the aphakia. A significant increase was reported after 1 year of aphakia. Clinical studies reported almost a 100% prevalence of PVD in aphakic eyes. In a postmortem study, 84% of eyes with intracapsular cataract extraction had PVD. Of eyes with extracapsular cataract extraction and posterior capsulotomy, 76% had PVD. Of eyes with extracapsular cataract extraction with an intact posterior capsule, 40% had PVD. It is this increased incidence of PVD that is a risk factor in the development of retinal breaks and subsequent RRD.

Epidemiology

Frequency

United States

The incidence of RRD following uncomplicated cataract extraction has been reported to be 0-3%. Most series report that about 50% of RRD occur during the first year following cataract surgery. [1Recent studies have shown that even though the risk for pseudophakic retinal detachment is highest during the first year after cataract surgery, the increased risk continues for at least 11 years. [23]

The incidence of RRD following penetrating keratoplasty (PKP) depends on whether the eye is phakic or pseudophakic and if the vitreous was manipulated. Several series report 2.4-6.8% of cases with RRD. [456]

Up to 3% of eyes undergoing pars plana vitrectomy (PPV) for nonclearing vitreous hemorrhage and 5% of eyes undergoing PPV for a macular pucker will develop RRD. In 55% of cases, the RRD appeared during the first 4 weeks. [7891011]

In a series of 765 patients undergoing strabismus surgery, 0.4% experienced an inadvertent retinal perforation, but none developed RRD. [12]

International

A 6-year retrospective review based on medical records and insurance claims from the Taiwan Bureau of National Health Insurance, revealed a cumulative 6-year rate of pseudophakic retinal detachment of 1.16%. [13]

A 5-year cataract surgery audit from the Singapore National Eye Centre revealed that 1.3% of over 48,000 cases of phacoemulsification were complicated by a rhegmatogenous retinal detachment. [14]

A large register-based cohort study of more than 200,000 Danish patients that underwent uncomplicated phacoemulsification showed that there is a 4-fold increase in risk of developing a retinal detachment following cataract surgery. [3]

A 2015 retrospective case series from an Irish population reported a retinal detachment incidence of 5.9% following implantation of Boston type I and II keratoprosthesis. [15]

In a large series from Saudi Arabia, the incidence of inadvertent globe perforation in strabismus surgery was 3 in 1000 with 1 eye developing a RRD. [16]

Mortality/Morbidity

Some earlier reports have emphasized the poorer outcome of RRD in pseudophakic eyes as compared to phakic eyes. Peripheral capsular opacification, lenticular remnants, and optical effects induced by the rim of the intraocular lens (IOL) may impair visualization of the small peripheral retinal breaks by indirect ophthalmoscopy, leading to missed breaks during surgical repair. However, most reports have shown similar results in the repair of primary phakic RRD compared to primary pseudophakic or aphakic RRD.

Sex

Postoperative RRD appears to be more common in men than in women. The 6-year cumulative pseudophakic retinal detachment rate was much higher in Taiwanese males (1.90%) than females (0.56%). [13When the fellow unoperated eye was used as a reference, sex did not modify the risk of developing a pseudophakic retinal detachment. [3]

Age

Since previous cataract surgery is a risk factor for the development of a retinal detachment, patients at risk tend to be those aged 50-90 years.



History

Since most postoperative retinal detachments are rhegmatogenous in nature, similar symptoms, such as photopsias, floaters, visual field defects, and central visual loss, are experienced by patients.

Physical

The findings are typical of rhegmatogenous retinal detachment (RRD) with the following special features:

  • The retinal breaks are often small and difficult to visualize.

  • The retinal breaks are often located along the posterior border of the vitreous base.

  • The retinal detachment is often extensive.

  • The macula is commonly involved.

Causes

As with all RRDs, vitreous traction is the main culprit.

Cataract extraction

Aphakia and pseudophakia, especially with an open posterior capsule, predispose to PVD.

Preoperative risk factors include myopia, young age, lattice degeneration, and a history of previous RRD in the fellow eye.

The most important intraoperative risk factor is vitreous loss. The cataract extraction technique (ie, extracapsular, intracapsular, phacoemulsification) does not appear to play a role. The placement of an IOL does not seem to play a role. Conflicting reports exist regarding the importance of the type of IOL placed. Some reports claim that anterior chamber intraocular lens (ACIOL) and iris clip lenses induce more inflammation, resulting in a higher incidence of proliferative vitreoretinopathy (PVR).

The most important postoperative factor is YAG capsulotomy.

Postoperative RRD after cataract extraction is more common in previously vitrectomized eyes regardless of the technique used.

In patients with atopic cataracts, the implantation of an IOL in-the-bag might prevent the contraction of the lens capsule and decrease the incidence of postoperative RRD.

Penetrating keratoplasty

Retinal breaks and detachments are rare in phakic eyes that undergo PKP.

RRDs are fairly common in aphakic or pseudophakic eyes that have undergone PKP, especially if an anterior vitrectomy was performed.

Pars plana vitrectomy

PPV may also be complicated by iatrogenic retinal breaks, which, if undetected, may lead to RRD. They commonly occur posterior to the sclerotomy site as a result of mechanical traction by the exchange of instruments through the sclerotomy. Most of these breaks will be detected and treated intraoperatively. The exception occurs during macular hole surgery in which the surgeon creates a PVD as part of the procedure. The iatrogenic breaks are not behind the sclerotomies as expected but tend to be inferior instead.

In patients with retained lens material, higher traction can be induced due to nuclear fragment manipulation. Recommended techniques for these patients include the following: the induction of PVD with maximal vitreous removal before phacofragmentation, lens fragment debulking before fragmentation, use of low energy with high aspiration during the removal of retained lens material, and intraoperative indirect ophthalmoscopic evaluation of the retinal periphery with scleral indentation to diagnose intraoperative retinal breaks.

Small-gauge transconjunctival sutureless vitrectomy has also been reported to cause iatrogenic postoperative RRD. This is thought to be related to the lack of adequate peripheral vitrectomy with the more flexible instruments and excessive traction at the sclerotomy sites. Studies have compared favorably the safety profile of the 23-gauge system to the 25-gauge system. In a recent retrospective case series of macular holes that underwent phacovitrectomy with either 20 or 23 gauge, the incidence of retinal breaks was higher with 20 gauge versus 23 gauge. [17]

Strabismus surgery

Inadvertent globe perforation during strabismus surgery has been reported to cause RRD. [16However, the incidence appears to be quite low. It is recommended that a high index of suspicion be maintained. If retinal perforation is suspected, indirect ophthalmoscopy should be performed to examine the retina. If necessary, cryotherapy or laser should be performed


Differential Diagnoses

Imaging Studies

B-scan ultrasonography

An IOL strongly reflects sound waves, so the transducer needs to be placed farther back, so the sound waves avoid the IOL.

Histologic Findings

The same histopathologic findings as in other rhegmatogenous retinal detachments (RRDs) are Found.



Medical Care

Medical treatment has no role in the treatment of postoperative retinal detachment.

Surgical Care

As with all RRDs, the goal is to identify and close all the retinal breaks. Several techniques, as they pertain to the repair of pseudophakic or aphakic RRD, are discussed below. The techniques are discussed in greater detail in Retinal Detachment, Rhegmatogenous.

Scleral buckle

Many surgeons like to use an extrascleral or intrascleral implant with encircling band in aphakic or pseudophakic detachments. They reason that the band can relieve vitreous traction that might lead to new break formation.

If a band is used, this should be placed at the posterior border of the vitreous base (usually 2.5-3 mm posterior to the insertion of the recti muscles). If it is placed posterior to the equator, it will be useless, since it will not be able to significantly relieve vitreous traction.

On the other hand, others have reported series using segmental elements with similar results.

Vitrectomy

This may be an ideal procedure for these cases. Axial opacities (eg, lenticular remnants, vitreous hemorrhage) may be removed easily. Vitreoretinal traction may be relieved in an efficient manner without regard to potential damage to the lens. The major complication of vitrectomy with intraocular tamponade is cataract formation, which is a nonissue in these eyes.

Fluid-air exchanges in pseudophakic eyes with an open capsule may pose a problem. Fluid condensation on the surface of the IOL may impair the visibility of the retina, making completion of the fluid-air exchange hazardous and impossible. Thus, if a pseudophakic eye has an intact capsule, do not create a posterior capsulotomy if fluid-air exchange is anticipated unless absolutely necessary. If the IOL is made of polymethyl methacrylate (PMMA) or acrylic, the posterior surface of the IOL may be wiped with a soft-tipped cannula to make the view better. In cases of a silicone IOL, coating the posterior surface with some silicone oil will make the view better.

Careful inspection and attention to detail are necessary since iatrogenic retinal breaks have been reported to occur in up to 16% of cases. [18]

In a prospective randomized study, the single surgery anatomic success rate was found to be higher in the primary vitrectomy group (94%) compared to the primary scleral buckling group (83%). [19These results have been confirmed by a prospective randomized multicenter clinical trial [20and a meta-analysis. [21]

Transconjunctival small-gauge vitrectomy has gained popularity in the past few years. 25-gauge transconjunctival vitrectomy was introduced in 2002. [22Several potential advantages over traditional 20-gauge vitrectomy have been described. These include improved patient comfort, faster wound healing, decreased inflammation, less conjunctival scarring, and a decrease in surgical time in opening and closing. [23In the beginning, 25-gauge vitrectomy had certain shortcomings. These included excessive flexibility of the instruments, poor illumination, decreased fluidics, and an increase in wound leakage.

The 23-gauge vitrectomy was developed in response to some of these shortcomings. [24In general, 23-gauge instruments exhibit more rigidity than 25-gauge instruments, which allows performing more peripheral maneuvers. Initially, both 25- and 23-gauge vitrectomy were mostly used in macular cases. However, as surgeons became more familiar and acquainted with both systems more complex cases were being operated on with transconjunctival small-gauge vitrectomy.

After a review of earlier reports, Heimann concluded that transconjunctival 25- and 23-gauge vitrectomy does not show any advantage over scleral buckling techniques in phakic eyes or 20-gauge vitrectomy in pseudophakic eyes. [20Furthermore, he claimed that transconjunctival 25- and 23-gauge vitrectomy worsen the outcome and increase the postoperative complication rate. [20]

Recent series suggest otherwise. A prospective case series of 22 consecutive eyes from one institution reported that the one operation success rate with 25-gauge transconjunctival vitrectomy for pseudophakic retinal detachments was 95.45% with final reattachment in 100%. Furthermore, 86% of eyes experienced an improvement in visual acuity. Transient hypotony that resolved spontaneously was reported in 9%. [25Another prospective case series of 15 eyes yielded similar results. [26]

Vitrectomy and scleral buckling

PPV, extrascleral or intrascleral buckling element with or without encircling band, internal drainage, and intraocular tamponade are effective and efficient methods of repairing primary pseudophakic retinal detachments. Reported complications were minimal. Final anatomical and visual results are comparable to previous reports. [2728Recent studies have shown that the visual and anatomic outcomes were very similar between primary vitrectomy and combined vitrectomy and scleral buckling calling into question the need of the implant and encircling band. [212728]

Pneumatic retinopexy

Some series report a lower success rate in pseudophakic eyes than phakic eyes. This is not surprising given the potential difficulty in examining the peripheral retina in these eyes. Reported single surgery anatomic success rates are in the order of 41-81% with final reattachment rates of 93-98%. [29]

Consultations

Prompt consultation with a vitreoretinal specialist is mandatory.

Activity

Depending on whether intraocular tamponade with a gas is used, the surgeon will instruct the patient to maintain a certain head position.



Medication Summary

Rhegmatogenous retinal detachment (RRD) is a surgical condition. 



Further Outpatient Care

According to the surgeon's discretion, an intraocular gas bubble may have been placed into the vitreous in the surgical repair of the RRD. If this is the case, the patient must adopt a certain head position for several weeks.

Further Inpatient Care

Most vitreoretinal procedures are performed as ambulatory outpatient procedures.

Inpatient & Outpatient Medications

Following vitreoretinal surgery, the patient is usually prescribed a topical prophylactic antibiotic, a topical corticosteroid (eg, prednisolone acetate), and a cycloplegic (eg, atropine 1%). The intraocular pressure is monitored during the postoperative period and treated as necessary with beta-blockers, alpha-agonists, carbonic anhydrase inhibitors, and prostaglandin analogs.

Deterrence/Prevention

It is good clinical practice that the general ophthalmologist dilates the pupil and examines the peripheral retina prior to cataract surgery and in the postoperative period after cataract surgery. If abnormalities are found, the patient should be referred to a vitreoretinal specialist for further management.

If a patient has risk factors for retinal detachment (eg, myopia, fellow eye retinal detachment, family history), a silicone IOL should not be placed. Instead, a foldable acrylic IOL is a better option.

Complications

PVR is the most common cause of failure of surgical retinal reattachment surgery.

Elevated intraocular pressure is common after either vitrectomy with intraocular tamponade or scleral buckling procedures. Most cases respond to topical medications. Very seldom does one have to release the buckle or withdraw gas from the vitreous cavity.

Endophthalmitis following vitrectomy is rare. A scleral buckle may become infected and may need to be removed.

Prognosis

Most series indicate that up to 95% of retinal detachment surgical cases are anatomical successes. Of these cases, as many as 50% obtain a visual acuity of 20/50 or better. [114]

In a retrospective longitudinal cohort analysis of 9216 Medicare beneficiaries diagnosed with a rhegmatogenous retinal detachment between 1991-2007, patients who had undergone primary pneumatic retinopexy were 3 times more likely to receive a second retinal detachment operation compared to scleral buckling or pars plana vitrectomy. Risk of additional retinal detachment surgery did not differ significantly between scleral buckling and pars plana vitrectomy. Patients who had a pars plana vitrectomy were 2 times more likely to suffer adverse events as compared with those who had scleral buckling. [30]

Patient Education

Patients should be educated regarding the symptoms of acute PVD, namely floaters and photopsia. Patients should be instructed to seek immediate attention if these symptoms occur.