Wipe-Out or Snuff-Out Phenomenon after Glaucoma Surgery
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Disease Entity
Disease
“Wipe-out” or “snuff-out” phenomenon [1] represents a rare but devastating complication following glaucoma surgery, characterized by idiopathic and irreversible loss of vision in the immediate postoperative period. While this phenomenon is commonly associated with glaucoma surgery, particularly trabeculectomy [2], cases following cataract surgery have also been reported [3]. Older studies focusing on glaucoma surgery have reported varying incidence rates ranging from 0.75% to 13.6% [1][4] of wipe-out phenomenon, though recent evidence suggests a much lower frequency [5][6]. The study by Topouzis et al. [7] is the first to evaluate outcomes of advanced glaucoma following surgical intervention prospectively. In contrast, most prior research has relied on retrospective analyses.
Etiology
The exact etiology of wipe-out phenomenon remains uncertain, with multiple potential mechanisms proposed in the literature. Following filtration surgery, several causative factors have been identified, including profound hypotony, suprachoroidal hemorrhage, cataract formation, cystoid macular edema, and retrobulbar anesthesia-induced trauma to the optic nerve and vascular structures. Additional contributing factors may include severe uveitis, and macular split fixation [1][7][8][9][10][11]. Studies suggest that preoperative factors such as advanced glaucoma with severely constricted visual fields may also predispose patients to this condition [8].
Risk Factors
| Risk Factor | ||
|---|---|---|
| General | Advanced age | Increased susceptibility in older patient populations[11] |
| Systemic conditions | History of cardiovascular disease and diabetes[3][11] | |
| Preoperative | Severe pre-operative visual field defects | Mean deviation (MD) < -20 dB on Humphrey visual field assessment[11] |
| Advanced glaucoma | Severe visual field loss and compromised optic nerve[2][5] | |
| Macular involvement | Preoperative macular split fixation on visual fields[1][7] | |
| Retinal vein occlusions | Increased risk in patients with retinal vein occlusions[3] | |
| Macular Involvement | Presence of macular split fixation[1][5] | |
| Postoperative | Severe hypotony | Intraocular pressure (IOP) ≤ 2 mmHg on the first postoperative day [1][6] |
| Choroidal effusions | Postoperative choroidal effusions which eventually resolve [11] | |
| Elevated postoperative IOP | Elevated intraocular pressure following surgery[3] |
General Pathology
In advanced glaucoma cases, the optic nerve exhibits significant compromise due to prolonged elevated intraocular pressure (IOP) and progressive loss of retinal ganglion cells. This structural weakness of the optic nerve head makes it particularly vulnerable to changes in ocular perfusion and pressure dynamics during and after surgery [7]. The pathological basis of the wipe-out phenomenon remains poorly defined due to its rarity and the lack of histopathological studies. Current understanding suggests involvement of ischemic optic neuropathy, mechanical damage, and vascular occlusion in this phenomenon.
Pathophysiology
The pathophysiology of the wipe-out phenomenon involves a complex interplay of mechanical, vascular, and ischemic factors. Rapid IOP reduction may cause mechanical deformation of the lamina cribrosa, resulting in damage to retinal ganglion cell axons. Post-operative hypotony can reduce perfusion pressure, leading to ischemia of the optic nerve head and retina. In patients with advanced glaucoma, the ability to autoregulate blood flow may be significantly impaired, making them particularly susceptible to IOP fluctuations. Postoperative inflammation or bleeding may exacerbate vascular compromise or directly damage the optic nerve. Bhadra et al. [5] suggest that sudden, intraoperative ocular hypotony during glaucoma surgery may result in optic nerve hemorrhage and decreased perfusion pressure to an already compromised optic nerve blood supply. This may also trigger microembolic episodes, potentially causing damage to the remaining nerve fibers.
Diagnosis
Wipe-out phenomenon is a clinical diagnosis with immediate loss in visual acuity with associated risk factors such as advanced glaucoma particularly those with pre-operative visual field defects. It is essential to rule out other possible causes of vision loss, such as retinal detachment, choroidal effusion, or optic neuropathy. Comprehensive postoperative evaluations, including optical coherence tomography (OCT), can help identify issues like progressive macular thinning. The American Academy of Ophthalmology recommends thorough preoperative and postoperative evaluations to monitor for this and other complications.[12]
History
Wipe-out phenomenon is a highly debated topic as certain literature has confirmed the presence of this following glaucoma surgery in an older patient with advanced glaucoma. During the presentation, the patient will indicate a sudden loss of central vision after surgery. Ocular pain and redness are not associated with this condition.[6]
Physical Examination
Assessing intraocular pressure and visual acuity is critical for diagnosis. Additionally, slit-lamp examination and gonioscopy are essential components of the physical exam when evaluating for wipe-out phenomenon. Dilated fundoscopy with the vertical cup-to-disc ratio evaluation is also crucial in this assessment.[1][7]
Signs/Symptoms
Clinically, patients present with a marked drop in intraocular pressure (IOP), often ≤ 2 mmHg, typically occurring one to two days after surgery. This is accompanied by a significant loss of visual acuity, primarily affecting the central visual field. [13] Visual acuity dropping to count fingers is not uncommon.
Diagnostic procedures
The diagnosis of wipe-out phenomenon is primarily clinical, with diagnostic procedures serving to confirm the condition and evaluate its severity.
- Standard Automated Perimetry (SAP)
- The Humphrey Visual Field (HFA) 10-2 program is well-suited for patients with advanced glaucoma as it assesses the central 10 degrees of the visual field. This region is essential for identifying central visual field defects and macular splitting, both of which are significant risk factors for wipe-out phenomenon.[14]
- Optical Coherence Tomography (OCT)
- Progressive macular thinning in patients with advanced glaucoma is a risk factor and close monitoring of this patient population will help assess risk/severity and also aid in the diagnosis. [13]
Differential diagnosis
- Hypotony Maculopathy
- Choroidal Effusion or Hemorrhage
- Lens Opacification
- Macular Edema
- Retinal Detachment
Management
The management of wipe-out phenomenon primarily focuses on prevention through careful patient selection and meticulous surgical technique. Preventive strategies include:
● Gradual IOP reduction to avoid sudden perfusion changes
● Use of adjunctive therapies like mitomycin-C during surgery for controlled IOP lowering
● Avoidance of excessive hypotony through perioperative management [8][11]
Medical therapy
Medical therapy focuses on stabilizing IOP and improving ocular perfusion, including:
● Cautious use of topical IOP-lowering agents such as prostaglandin analogs, beta-blockers, and carbonic anhydrase inhibitors to avoid excessive reduction
● Systemic carbonic anhydrase inhibitors for IOP control when elevated
● Topical or systemic steroids to reduce inflammation and improve perfusion
● Medications such as pentoxifylline to improve blood flow to the optic nerve[7]
Medical follow up
Close postoperative monitoring is essential for optimal outcomes. The follow-up regimen should include:
● Weekly assessments during the first month to evaluate IOP and visual acuity
● Monthly follow-ups for 6 months to detect complications such as choroidal detachment or macular edema
● Regular visual field testing to assess for progression of visual field loss
● OCT or other imaging modalities to evaluate optic nerve structure
● Patient education regarding prognosis and potential for irreversible vision loss [5][6]
Frequent IOP checks should be performed in the postoperative period, with particular attention to signs of hypotony or inflammation that could exacerbate the condition.
Surgery
Surgical management strategies have been documented and have shown success in reducing the incidence of wipe-out phenomenon.
Non-Penetrating Deep Sclerectomy (NPDS): NPDS involves the excision of sclerocorneal tissue under a partial thickness scleral flap, leaving a thin window of trabecular meshwork and Descemet membrane. This procedure has been shown to significantly reduce intraocular pressure (IOP) while minimizing the risk of wipe-out phenomenon.[6]
Trabeculectomy with Mitomycin-C: Mitomycin C is a potent antifibrotic agent. Its primary function is to inhibit fibroblast proliferation and reduce scarring at the surgical site, which is a common cause of surgical failure in glaucoma filtration surgeries.[15] [16] In a prospective analysis of patients with advanced glaucoma undergoing surgery with the use of Mitomycin-C, there were no significant changes in visual acuity, no postoperative complications, and no evidence of wipe-out phenomenon.
Prognosis
The available literature on the prognosis of this disease is limited; however, the overall prognosis is generally poor.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Costa VP, Smith M, Spaeth GL, Gandham S, Markovitz B. Loss of visual acuity after trabeculectomy. Ophthalmology. 1993;100(5):599-612. doi:10.1016/s0161-6420(93)31597-6
- ↑ 2.0 2.1 Abdelrahman A, ElSaied HebaMA, Allam RihamSHM, Osman M. ‘Wipe-out’ after subscleral trabeculectomy in advanced glaucoma patients. Delta J Ophthalmol. 2017;18(2):94. doi:10.4103/DJO.DJO_44_16
- ↑ 3.0 3.1 3.2 3.3 Ramsden C, Shweikh Y, Kam R, Bunce C, Foot B, Viswanathan A. Estimating the rate of severe visual loss (wipe-out) following cataract surgery, a British Ophthalmological Surveillance Unit (BOSU) study. Eye. 2023;37(18):3787-3792. doi:10.1038/s41433-023-02606-9
- ↑ Kolker AE. Visual prognosis in advanced glaucoma: a comparison of medical and surgical therapy for retention of vision in 101 eyes with advanced glaucoma. Trans Am Ophthalmol Soc. 1977;75:539-555.
- ↑ 5.0 5.1 5.2 5.3 5.4 Bhadra TR, Ghosh RP, Saurabh K, Mitra A, Ghosh AK, Bhadra T. Prospective evaluation of wipe-out after glaucoma filtration surgery in eyes with split fixation. Indian Journal of Ophthalmology. 2022;70(10):3544-3549. doi:10.4103/ijo.IJO_501_22
- ↑ 6.0 6.1 6.2 6.3 6.4 Leleu I, Penaud B, Blumen-Ohana E, et al. Risk assessment of sudden visual loss following non-penetrating deep sclerectomy in severe and end-stage glaucoma. Eye. 2019;33(6):902. doi:10.1038/s41433-019-0336-z
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 Topouzis F, Tranos P, Koskosas A, et al. Risk of Sudden Visual Loss Following Filtration Surgery in End-Stage Glaucoma. American Journal of Ophthalmology. 2005;140(4):661.e1-661.e7. doi:10.1016/j.ajo.2005.04.016
- ↑ 8.0 8.1 8.2 Moster MR, Moster ML. Wipe-Out: A Complication of Glaucoma Surgery or Just a Blast From the Past? American Journal of Ophthalmology. 2005;140(4):705-706. doi:10.1016/j.ajo.2005.05.024
- ↑ Sullivan KL, Brown GC, Forman AR, Sergott RC, Flanagan JC. Retrobulbar anesthesia and retinal vascular obstruction. Ophthalmology. 1983;90(4):373-377. doi:10.1016/s0161-6420(83)34547-4
- ↑ Karadimas P, Papastathopoulos KI, Bouzas EA. Decompression retinopathy following filtration surgery. Ophthalmic Surg Lasers. 2002;33(2):175-176.
- ↑ 11.0 11.1 11.2 11.3 11.4 11.5 Francis BA, Hong B, Winarko J, et al. Visual loss and recovery after trabeculectomy. Risk and associated risk factors. Arch Ophthalmol. 2022;129:1011-1017.
- ↑ Gedde SJ, Vinod K, Wright MM, Muir KW, Lind JT, Chen PP, Li T, Mansberger SL; American Academy of Ophthalmology Preferred Practice Pattern Glaucoma Panel. Primary Open-Angle Glaucoma Preferred Practice Pattern®. Ophthalmology. 2021 Jan;128(1):P71-P150. doi: 10.1016/j.ophtha.2020.10.022. Epub 2020 Nov 12. PMID: 34933745.
- ↑ 13.0 13.1 Mohammadzadeh V, Galian K, Martinyan J, Nouri-Mahdavi K. Vision Loss After Glaucoma Surgery: Progressive Macular Thinning as a Sign of Snuff-Out Phenomenon. J Glaucoma. 2019 Jun;28(6):e99-e102. doi: 10.1097/IJG.0000000000001202. PMID: 30694880.
- ↑ Asaoka R, Sugisaki K, Inoue T, Yoshikawa K, Kanamori A, Yamazaki Y, Ishikawa S, Uchida K, Iwase A, Araie M; For Advanced Glaucoma Study Members in Japan Glaucoma Society; for Advanced Glaucoma Study Members in Japan Glaucoma Society. Identifying central 10° visual subfield associated with future worsening of visual acuity in eyes with advanced glaucoma. Br J Ophthalmol. 2023 Dec 18;108(1):71-77. doi: 10.1136/bjo-2022-321481. PMID: 36418145.
- ↑ Wolters JEJ, van Mechelen RJS, Al Majidi R, Pinchuk L, Webers CAB, Beckers HJM, Gorgels TGMF. History, presence, and future of mitomycin C in glaucoma filtration surgery. Curr Opin Ophthalmol. 2021 Mar 1;32(2):148-159. doi: 10.1097/ICU.0000000000000729. PMID: 33315724.
- ↑ Grover DS, Kornmann HL, Fellman RL. Historical Considerations and Innovations in the Perioperative Use of Mitomycin C for Glaucoma Filtration Surgery and Bleb Revisions. J Glaucoma. 2020 Mar;29(3):226-235. doi: 10.1097/IJG.0000000000001438. PMID: 31913225.
