CaseWise 2 – Choroidal effusion and bleb encapsulation post AGV

Dr. Jyotsna Jareda, Dr. Prabhat Nangia, Dr. Vinay Nangia
Suraj Eye Institute, Nagpur, India

Introduction:
Ahmed glaucoma valve (AGV) is a surgical technique to reduce Intraocular pressure (IOP) in patients having glaucoma. Choroidal effusion and encysted bleb are common problems encountered with AGV. Choroidal effusion is an abnormal accumulation of fluid in the suprachoroidal space.The precipitating factor for the serous choroidal detachment is usually hypotony.2  An encapsulated cyst develops when Tenon’s capsule adheres to the episclera forming a high, domed, smooth, two-layered bleb.3 The encapsulated cyst is impervious to aqueous humor, which results in IOP elevation. We present to you a case, who developed choroidal effusion and bleb encystment after AGV implantation.


Case report :
A male, 59 years of age, presented to us with blurring of vision in Right eye (RE) since 1 year. Best corrected visual acuity (BCVA) in Right eye (RE) was perception of light  and in Left eye (LE) was 6/6. On slit lamp biomicroscopy examination, RE pupil was sluggishly reacting with nuclear sclerosis grade 4 lens and phacodonesis and subluxation. Anterior chamber (AC) was shallow with vitreous in AC. LE on slit lamp biomicroscopy showed shallow anterior chamber, rest was normal. Intra-ocular pressure (IOP) measured with Goldmann applanation tonometer in RE was 50 mm hg and in LE was 10 mm hg. RE showed vertical cup C:D ratio (VCDR) of 0.95 and LE VCDR of 0.85.

Management:
Patient was advised RE cataract extraction along with anterior vitrectomy, Ahmed glaucoma valve  and scleral fixated intraocular implantation, which was done on 13/04/19. He was advised LE trabeculectomy, which was done on 18/2/2019. Patient developed large choroidal in RE (Fig. 1)  after surgery, which was drained on 22/4/2019. 1 month post operation, BCVA in RE was 6/9 and in LE was 6/6. IOP in RE was 16 mmhg and LE was 12 mmhg. Patient was kept under regular follow up and was started on Brimonidine 0.2% and Timolol 0.5%  eye drop in both eyes On review after 3 month IOP In RE was 17 mm hg and in LE was 13 mm hg. Anterior segment evaluation showed large bleb encapsulation in RE which was punctured on slit lamp using 26 g needle. There was reduction in height of bleb encapsulation following needle puncture and IOP was reduced  to 8 mm hg.

Figure 1. RE B scan showing choroidal effusion.

Figure 2: RE slit lamp photograph, showing tube placed in anterior chamber and encysted bleb.

Discussion:
Choroidal effusions and bleb encystment are common problem encountered with AGV. Meticulous surgical steps and preventive measures may help to reduce the risk of choroidal effusions. Our patient developed choroidal effusion associated with sudden reduction in IOP following AGV implantation. While most choroidal effusions may resolve on conservative management, we preferred surgical management so as to restore normal anatomy and early visual recovery. Bleb encystment after AGV is a vexing problem as it leads to increased IOP. We punctured the cyst on slit lamp and postoperative aqueous suppressants was started in our patient. Decapsulation and valve reimplantation procedures have been tried and found to be successful in cases of encapsulated blebs.3

References:
  1. Schrieber C, Liu Y. Choroidal effusions after glaucoma surgery. Current opinion in ophthalmology. 2015 Mar 1;26(2):134-42.https://journals.lww.com/co-ophthalmology/Abstract/2015/03000/Choroidal_effusions_after_glaucoma_surgery.12.aspx
  2. Vijaya L, Manish P, Ronnie G, Shantha B. Management of complications in glaucoma surgery. Indian journal of ophthalmology. 2011 Jan;59(Suppl1):S131. doi: 10.4103/0301-4738.73689.
  3. Al-Mosallamy SM. Decapsulation versus valve re implantation in cases with an encysted Ahmed valve in refractory glaucoma. Delta Journal of Ophthalmology. 2015 Jan 1;16(1):22. http://djo.eg.net/article.asp?issn=1110-9173;year=2015;volume=16;issue=1;spage=22;epage=26;aulast=Al-Mosallamy

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