Intravitreal Triamcinolone Acetonide for Persisting Cystoid Macular Edema After Penetrating Keratoplasty

Current management options for the treatment of refractory postoperative cystoid macular edema: A systematic review

Post-operative cystoid macular edema (PCME) is an important complication following intraocular surgery that often resolves spontaneously without treatment. In some cases, PCME may persist despite initial medical therapy, which can adversely impact visual outcomes. Various topical, intraocular and systemic treatments exist for the prevention and management of cystoid macular edema; however, there is no consensus on treatment of refractory cases in the postoperative setting. In accordance with the PRISMA guidelines, we systematically reviewed 68 articles describing management options and their outcomes for treatment-resistant cases of PCME. The most commonly reported treatments included steroid (39 studies) and biological-based (17 studies) therapies. We provide an overview of the treatment options for refractory PCME.

Intravitreal steroids for the treatment of retinal diseases

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events.

Drug safety evaluation of intravitreal triamcinolone acetonide

INTRODUCTION

Triamcinolone acetonide (TA) is a steroidal drug that has been widely administered intravitreally for retinal and choroidal conditions. Safety of steroidal products for intraocular use is essential because of their risk of ocular adverse events. This review comprehensively discusses the safety of intravitreal administration of TA.

AREAS COVERED

This paper analyzes the mechanisms of action and key pharmacokinetic attributes and provides a discussion of the main clinical trials investigating clinical applications of intravitreal TA. The safety of intravitreal TA is evaluated through a search of the Medline database from 1980 to 2011. The most relevant literature on the safety of intravitreal TA is also discussed.

EXPERT OPINION

The complications of intravitreal TA therapy include secondary ocular hypertension in about 20 - 40% of eyes, steroid-induced cataract in about 15 - 20% of cases and postinjection infectious endophthalmitis and pseudoendophthalmitis in less than 1%. TA is an effective drug for various retinal and choroidal diseases when delivered intravitreally. It may imply an off-label use and it may be associated with ocular adverse events. Intravitreal TA is not associated with significant systemic safety risks.

Comparison of macular thickness measured by optical coherence tomography after deep anterior lamellar keratoplasty and penetrating keratoplasty

PURPOSE

To compare the postoperative macular thickness changes using optical coherence tomography (OCT) in eyes that underwent deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP).

DESIGN

Prospective, nonrandomized clinical trial.

METHODS

Sixty eyes of 60 patients (32 male, 28 female) with keratoconus who underwent corneal transplant surgery in an institutional setting were included in the study. Thirty eyes underwent DALK and 30 eyes underwent PKP. All eyes underwent corrected visual acuity (CVA) measurement and macular thickness measurement using spectral-domain OCT preoperatively, and 1 week, 1 month, 3 months, and 6 months postoperatively. The main outcome measures were CVA and macular thickness.

RESULTS

The DALK group had significantly better mean CVA than that of the PKP group at 1-month (P < .001), 3-month (P = .002), and 6-month (P = .040) follow-ups. The mean macular thickness significantly increased at 1 week after PKP surgery, remained stable at 1-month follow-up, and decreased at 3- and 6-month follow-ups. On the other hand, the mean macular thickness remained stable during 6 months after DALK. Although there was no significant difference between groups preoperatively (P = .970) and at 6-month follow-up (P = .339), the PKP group had significantly higher mean macular thickness than that of the DALK group at 1-week (P < .001), 1-month (P < .001), and 3-month (P = .005) follow-ups.

CONCLUSION

Although mean macular thickness increases and peaks around 1 month and returns back to normal levels at 6 months after PKP surgery, it does not change after DALK.

Pharmacotherapeutic efficacy of preservative-free intravitreal triamcinolone acetonide

Preservative-free formulations of triamcinolone acetonide have recently been introduced to the market over concerns of local toxicity of the vehicle and preservatives, including benzyl alcohol in the original formulation, which was not designed for intraocular use. The pharmacokinetics and pharmacodynamics of intravitreal triamcinolone (IVTA) are discussed. The therapeutic effects of IVTA include improvement of visual acuity and reduction of macular edema. However, ongoing treatment is usually required to maintain its effects. The efficacy of IVTA for both FDA-approved and 'off-labeled' indications is reviewed. Elevation of intraocular pressure and cataract formation are the two major side effects of IVTA; these are manageable but require close long-term follow-up. More studies are required to determine the optimal dosage and treatment frequency in different posterior segment disease.

Intravitreal triamcinolone for intraocular inflammation and associated macular edema

Triamcinolone acetonide (TA) is a corticosteroid that has many uses in the treatment of ocular diseases because of its potent anti-inflammatory and anti-permeability actions. Intraocular inflammation broadly referred to as uveitis can result from several causes, including the immune system and after ophthalmic surgery. One of the most common reasons for vision loss with uveitis is macular edema. TA has been used for many years as an intravitreal injection for the treatment of ocular diseases. Several case control studies have been reported showing the efficacy of TA in the treatment of intraocular inflammation and associated macular edema caused by Behcet's disease, Vogt-Koyanagi-Harada syndrome, sympathetic ophthalmia and white dot syndromes. It has also been shown efficacious in cases of pars planitis and idiopathic posterior uveitis. Some authors have reported its use in postoperative cystoid macular edema. Many of the studies on the use of TA in controlling intraocular inflammation and concomitant macular edema showed its effect to be transient in many patients requiring reinjection. Complications can arise from intravitreal injection of TA including elevated intraocular pressure and cataract. Rarely, it can be associated with infectious and non-infectious endophthalmitis. TA may be useful as an adjuvant in the treatment of uveitis and its associated macular edema, especially in patients resistant or intolerant to standard treatment.

Intracameral triamcinolone acetonide as treatment for endothelial allograft rejection after penetrating keratoplasty

PURPOSE

Intracameral injection of triamcinolone acetonide as treatment of therapy-resistant endothelial allograft rejection after penetrating keratoplasty is reported.

METHODS

A 32-year-old patient showed conventional therapy-resistant endothelial allograft rejection 2 months after penetrating keratoplasty. The patient received an intracameral injection of 4 mg in 0.1 mL of triamcinolone acetonide. Preinjection visual acuity was count fingers at 3 ft, and the graft showed diffuse haze and multiple endothelial rejection lines.

RESULTS

Within 2 weeks after injection, marked resolution of the microcystic edema and reversal of the endothelial rejection was noted. Fourteen months after injection, best-corrected visual acuity was 20/20, and intraocular pressure was 17 mm Hg without antiglaucoma therapy.

CONCLUSIONS

Intracameral injection of triamcinolone acetonide may be an additional treatment modality in the treatment of endothelial allograft rejection when traditional steroid therapies have failed.

Intravitreal triamcinolone acetonide: a change in a paradigm

BACKGROUND

Based on experimental studies and clinical observations by Robert Machemer, Gholam Peyman and others, the vitreous cavity has increasingly been used as a reservoir of drugs for the direct treatment of intraocular diseases.

METHODS AND RESULTS

The most widely injected drug so far has been triamcinolone acetonide for various intraocular neovascular and edematous diseases. Comparing the various diseases with respect to effect and side effects of the treatment, the best response in terms of gain in visual acuity has been achieved for intraretinal edematous diseases such as diffuse diabetic macular edema, branch retinal vein occlusion, central retinal vein occlusion, and pseudophakic cystoid macular edema. In eyes with various types of noninfectious uveitis including acute or chronic sympathetic ophthalmia and Adamantiadis-Behçet's disease, visual acuity increased and the degree of intraocular inflammation decreased. Some studies have suggested that intra- vitreal triamcinolone may be useful as an angiostatic agent in eyes with iris neovascularization and proliferative ischemic retinopathies. Intravitreal triamcinolone may possibly be helpful as adjunct therapy for exudative age-related macular degeneration, particularly in combination with photodynamic therapy. In eyes with chronic, therapy-resistant ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure and may stabilize the eye. The complications of intravitreal triamcinolone therapy include secondary ocular hypertension in about 40% of the eyes injected; medically uncontrollable high intraocular pressure leading to antiglaucomatous surgery in about 1-2% of the eyes; posterior subcapsular cataract and nuclear cataract leading to cataract surgery in about 15-20% in elderly patients within 1 year after injection; postoperative infectious endophthalmitis with a rate of about 1:1,000; noninfectious endophthalmitis, perhaps due to a reaction to the solvent agent, and pseudoendophthalmitis with triamcinolone acetonide crystals appearing in the anterior chamber. Intravitreal triamcinolone injection can be combined with other types of intraocular surgery including cataract surgery, particularly in eyes with iris neovascularization. Cataract surgery performed some months after the injection does not show a markedly elevated complication rate. The injection may be repeated, if vision redecreases. In nonvitrectomized eyes, the duration of the effect and side effects of a single intravitreal injection of triamcinolone is about 6-9 months for a dosage of about 20 mg, and about 2-4 months for a dosage of 4 mg. It has remained unclear so far, whether and how to remove the solvent agent. In the future, intravitreal triamcinolone may be combined with other antiangiogenic drugs for the treatment of exudative age-related macular degeneration or with neuroprotective drugs for treatment of diabetic retinopathy.

CONCLUSIONS

Despite an exponentially increasing number of mostly case-series studies, the intravitreal injection of triamcinolone may still be considered an experimental procedure until randomized studies have been presented.