We report a case of consecutive bilateral decompression retinopathy which occured following anterior chamber paracentesis in a patient with diabetic eye disease associated with neovascular glaucoma (NVG).

A 51-year old man with type 2 diabetes mellitus was admitted with the complaint of decreasing visual acuity in both eyes for twenty days. Best corrected visual acuity was 2/10 and finger counting from 50cms; intraocular pressures (IOP) were 78 mHg and 80 mHg in the right and left eyes, respectively. Slit lamp biomicroscopic examination revealed corneal edema, rubeosis iridis and slight posterior subcapsular cataracts bilaterally (OU). On gonioscopy, 360 degrees synechial angle closure was seen in both eyes. On fundoscopy, there was central retinal arterial pulsation in the right eye and severe nonproliferative diabetic retinopathy with clinically significant macular edema bilaterally.

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Figure 1. Compromised fundus view with decompression retinopathy due to anterior chamber hemorrhage.

Despite immediate medical treatment with intravenous hyperosmotic agents, oral acetozolamide 250 mg, topical dorzolamide/timolol and topical brimonidin, retinal arterial pulsation was persistent. Therefore an anterior chamber paracentesis was performed to decrease IOP to salvage central retinal artery flow in the right eye. Aqueous humor was drained passively by using a 30-gauge needle attached to a tuberculin syringe without a plunger. Right after the procedure visual acuity decreased to counting fingers and IOP had dropped to 7 mmHg. On slit lamp biomicroscopy, hyphema was present. Immediate fundus examination revealed decompression retinopathy with multiple widespread round retinal hemorrhages also involving the fovea. Central retinal artery pulsation had ceased. On the following day, IOP was 23 mmHG OD and 62 mmHG OS. Panretinal photocoagulation was initiated to the right eye and intravitreal rhanibizumab injectin was planned to the left as the fundus view did not allow photocoagulation because of corneal edema. After 0.3mg/0.05 ml ranibizumab (Lucentis; Novartis AG, Basel, Switzerland) injection to the left eye, paracentesis was performed as IOP which was initially high raised to a higher level after the injection. Hyphema and ocular decompression retinopathy also developed in the left eye. IOP was 15 mmHg right after the procedure.

Ocular decompression retinopathy, first described by Fechtner et al. has been reported frequently after filtering surgery [1]. It is a rare complication characterized by widespread retinal hemorrhages especially at the posterior pole. Visual prognosis associated with macular involvement changes case to case.

Etiology of ocular decompression retinopathy is not exactly known. There are several hypothesis for the pathogenesis [2] [3]. Defective vascular autoregulation as in longstanding glaucoma may increase the susceptibility to its development [1] [2] [3] [4] [5] [6]. Sudden increase of retinal blood flow secondary to hypotony facilitates the occurence of multiple retinal hemorrhages in patients predisposed. Based on duration and level of hypertonia, structural changes occur in eye tissues. Sudden drop in IOP resulting in a forward displacement of the lamina cribrosa that leads to blockage of axonal transport and compression of central retinal vein or increased retinal capillary fragility caused by inherited or acquired vascular disorders are other possibilities.

Anterior chamber paracentesis is a useful method for decreasing intolerably elevated IOP [5] [6] [2]. Acute hypotony may develop after anterior chamber paracentesis which may be an important predisposing factor for decompression retinopathy.

In the patient reported herein, it is possible that defective vascular autoregulation and capillary fragility were present due to neovascular glaucoma and diabetes mellitus. The development of multipl retinal hemorrhages in both eyes is in support of this finding. Intravitreal anti-VEGF injection is an essential therapeutic step which is performed to regress angle and iris neovascularisation until panretinal photocoagulation takes effect and to provide a window period for successful filtration surgery. While intravitreal anti-VEGF is of utmost importance in therapy, paracentesis is usually required for elevation of IOP following injection which may lead to decompression retinopathy that may further compromise vision. Hyphema is a well known complication of paracentesis in neovascular glaucoma whereas decompression retinopathy following paracentesis for high IOP due to anti-VEGF injection has not been reported before.

We describe a case of consecutive bilateral decompression retinopathy which developed following anterior chamber paracentesis in a case of diabetic eye disease and NVG. In predisposed patients with known risk factors, the risk of ocular decompression retinopathy is increased after paracentesis and a sudden drop of IOP should be avoided although it may be an inevitable step throughout the management process of this severe condition as in the case reported herein.

No author has any financial or proprietary interest in any material or method mentioned.