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Acute aqueous misdirection syndrome: Pathophysiology and management
LETTERS
Acute aqueous misdirection syndrome: Pathophysiology and management We appreciate Lau et al.1 formally describing the syndrome of acute anterior chamber shallowing and increase of intraocular pressure with no choroidal effusion. However, we believe this syndrome has been described under different names, including infusion misdirection syndrome, capsular block, intraoperative fluid misdirection, and subcapsular fluid entrapment.2,A The pathophysiology of the syndrome is based on the inappropriate “movement of the balanced salt solution via the zonular fibers.”1 Thus, we suggest that it should be called acute aqueous misdirection syndrome as this better describes the nature of the syndrome rather than one of its signs. Aqueous misdirection syndrome, also called malignant glaucoma based on similar pathophysiology of trapping fluid in the posterior segment, is characterized by a similar clinical picture but usually occurs from a few days to months or years after the initial surgery.3 This could be termed chronic aqueous misdirection syndrome. We agree that acute aqueous misdirection syndrome is probably underreported; anecdotally, most surgeons admit to having experienced it occasionally. The common theme is that it occurs toward the end of irrigation/aspiration (I/A), making the completion of I/A or the insertion of an intraocular lens impossible because of a flat anterior chamber. Irrigating fluid is known to be able to travel through intact zonular fibers into Berger space. This may occur rapidly toward the end of I/A, explaining the occurrence of the syndrome. The unconventional use of the residual cortical fiber irrigation maneuver in the authors' practice may account for the relatively high frequency with which the acute aqueous misdirection syndrome is encountered. The use a of a straight transconjunctival transscleral needle puncture of the pars plana with aspiration of retrocapsular liquid poses some risks, including postoperative hypotony and increased risk for endophthalmitis. Aspiration of fluid using a needle from the posterior segment of the eye risks engaging vitreous, causing retinal traction and risking retinal tear formation. There is also the chance of inadvertently engaging the posterior capsule. We suggest that when faced with acute aqueous misdirection syndrome, it would be preferable to use a small gauge trocar/cannula vitrectomy cutter (23-, 25-, or 27-gauge). The incision in the pars plana should be made after displacing the conjunctiva and then fashioning a 2-step beveled incision, as is modern Q 2014 ASCRS and ESCRS Published by Elsevier Inc.
practice for pars plana entries.4 The cutter can then remove retrocapsular fluid using a high cut rate; if any vitreous were engaged, there would be negligible retinal traction. It behooves us to absorb the lessons learned by our posterior segment colleagues about a decade ago. Andrzej Grzybowski, MD, PhD Pozna n-Olsztyn, Poland Somdutt Prasad, MS FRCSEd, FRCOphth, FACS Kolkata, India REFERENCES 1. Lau OCF, Montfort JM, Sim BWC, Lim CHL, Chen TSC, Ruan CW, Agar A, Francis IC. Acute intraoperative rock-hard eye syndrome and its management. J Cataract Refract Surg 2014; 40:799–804 2. Olson RJ, Younger KM, Crandall AS, Mamalis N. Subcapsular fluid entrapment in extracapsular cataract surgery. Ophthalmic Surg 1994; 25:688–689 3. Sharma A, Sii F, Shah P, Kirkby GR. Vitrectomy–phacoemulsification–vitrectomy for the management of aqueous misdirection syndromes in phakic eyes. Ophthalmology 2006; 113:1968–1973 4. Inoue M, Shinoda K, Shinoda H, Kawamura R, Suzuki K, Ishida S. Two-step oblique incision during 25-gauge vitrectomy reduces incidence of postoperative hypotony. Clin Exp Ophthalmol 2007; 35:693–696
OTHER CITED MATERIAL A. Dewey SH, “Please Give Me Another Chance. Intraoperative Fluid Misdirection Associated With Unexpected Coughing,” presented at the annual meeting of the American Academy of Ophthalmology, Orlando, Florida, USA, October 2011. Syllabus, pp 109–110. Available at: http://www.aao.org/pdf/RefractiveSurgery-2011-Syllabus.pdf. Accessed August 8, 2014
Reply : The issues raised by Drs. Grzybowski and Prasad (the correspondents), addressed in order in the paragraphs below, have allowed us to refine our thinking about acute intraoperative rock-hard eye syndrome (AIRES). Paragraph 1: While we appreciate the point that AIRES or its terminological equivalent is not new, previous descriptions such as infusion misdirection syndrome1 and subcapsular fluid entrapment2 allude to a presumed pathogenesis that has yet to be clearly elucidated. Additionally, they fail to reflect the fulminant and serious nature of this surgical disorder. We think that AIRES precisely describes the patient with an intraoperative rigid eye without a choroidal hemorrhage and also highlights the need for immediate intervention. Paragraph 2: The correspondents suggest the alternative term acute aqueous misdirection syndrome. The anterior chamber volume of 220 mL of aqueous is unlikely http://dx.doi.org/10.1016/j.jcrs.2014.10.016 0886-3350
2167
Acute aqueous misdirection syndrome: Pathophysiology and management We appreciate Lau et al.1 formally describing the syndrome of acute anterior chamber shallowing and increase of intraocular pressure with no choroidal effusion. However, we believe this syndrome has been described under different names, including infusion misdirection syndrome, capsular block, intraoperative fluid misdirection, and subcapsular fluid entrapment.2,A The pathophysiology of the syndrome is based on the inappropriate “movement of the balanced salt solution via the zonular fibers.”1 Thus, we suggest that it should be called acute aqueous misdirection syndrome as this better describes the nature of the syndrome rather than one of its signs. Aqueous misdirection syndrome, also called malignant glaucoma based on similar pathophysiology of trapping fluid in the posterior segment, is characterized by a similar clinical picture but usually occurs from a few days to months or years after the initial surgery.3 This could be termed chronic aqueous misdirection syndrome. We agree that acute aqueous misdirection syndrome is probably underreported; anecdotally, most surgeons admit to having experienced it occasionally. The common theme is that it occurs toward the end of irrigation/aspiration (I/A), making the completion of I/A or the insertion of an intraocular lens impossible because of a flat anterior chamber. Irrigating fluid is known to be able to travel through intact zonular fibers into Berger space. This may occur rapidly toward the end of I/A, explaining the occurrence of the syndrome. The unconventional use of the residual cortical fiber irrigation maneuver in the authors' practice may account for the relatively high frequency with which the acute aqueous misdirection syndrome is encountered. The use a of a straight transconjunctival transscleral needle puncture of the pars plana with aspiration of retrocapsular liquid poses some risks, including postoperative hypotony and increased risk for endophthalmitis. Aspiration of fluid using a needle from the posterior segment of the eye risks engaging vitreous, causing retinal traction and risking retinal tear formation. There is also the chance of inadvertently engaging the posterior capsule. We suggest that when faced with acute aqueous misdirection syndrome, it would be preferable to use a small gauge trocar/cannula vitrectomy cutter (23-, 25-, or 27-gauge). The incision in the pars plana should be made after displacing the conjunctiva and then fashioning a 2-step beveled incision, as is modern Q 2014 ASCRS and ESCRS Published by Elsevier Inc.
practice for pars plana entries.4 The cutter can then remove retrocapsular fluid using a high cut rate; if any vitreous were engaged, there would be negligible retinal traction. It behooves us to absorb the lessons learned by our posterior segment colleagues about a decade ago. Andrzej Grzybowski, MD, PhD Pozna n-Olsztyn, Poland Somdutt Prasad, MS FRCSEd, FRCOphth, FACS Kolkata, India REFERENCES 1. Lau OCF, Montfort JM, Sim BWC, Lim CHL, Chen TSC, Ruan CW, Agar A, Francis IC. Acute intraoperative rock-hard eye syndrome and its management. J Cataract Refract Surg 2014; 40:799–804 2. Olson RJ, Younger KM, Crandall AS, Mamalis N. Subcapsular fluid entrapment in extracapsular cataract surgery. Ophthalmic Surg 1994; 25:688–689 3. Sharma A, Sii F, Shah P, Kirkby GR. Vitrectomy–phacoemulsification–vitrectomy for the management of aqueous misdirection syndromes in phakic eyes. Ophthalmology 2006; 113:1968–1973 4. Inoue M, Shinoda K, Shinoda H, Kawamura R, Suzuki K, Ishida S. Two-step oblique incision during 25-gauge vitrectomy reduces incidence of postoperative hypotony. Clin Exp Ophthalmol 2007; 35:693–696
OTHER CITED MATERIAL A. Dewey SH, “Please Give Me Another Chance. Intraoperative Fluid Misdirection Associated With Unexpected Coughing,” presented at the annual meeting of the American Academy of Ophthalmology, Orlando, Florida, USA, October 2011. Syllabus, pp 109–110. Available at: http://www.aao.org/pdf/RefractiveSurgery-2011-Syllabus.pdf. Accessed August 8, 2014
Reply : The issues raised by Drs. Grzybowski and Prasad (the correspondents), addressed in order in the paragraphs below, have allowed us to refine our thinking about acute intraoperative rock-hard eye syndrome (AIRES). Paragraph 1: While we appreciate the point that AIRES or its terminological equivalent is not new, previous descriptions such as infusion misdirection syndrome1 and subcapsular fluid entrapment2 allude to a presumed pathogenesis that has yet to be clearly elucidated. Additionally, they fail to reflect the fulminant and serious nature of this surgical disorder. We think that AIRES precisely describes the patient with an intraoperative rigid eye without a choroidal hemorrhage and also highlights the need for immediate intervention. Paragraph 2: The correspondents suggest the alternative term acute aqueous misdirection syndrome. The anterior chamber volume of 220 mL of aqueous is unlikely http://dx.doi.org/10.1016/j.jcrs.2014.10.016 0886-3350
2167