SD = standard deviation. SD = standard deviation. [4570] Long-term outcomes for retinal nerve fiber layer after acute primary angle closure in Brazilians and risk factors for the severity of the retinal reduction Rafael Mérula1,2, Sebastião Cronemberger1,2, Érica de Abreu Borges1,2, and Nassim Calixto1,2 1Department of Ophthalmology and Otorhinolaryngology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; 2Hospital São Geraldo, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil INTRODUCTION Acute primary angle closure (APAC) is an ophthalmic emergency and a potentially blinding disease. Optic nerve damage can occur after the sudden rise in intraocular pressure (IOP) associated with an APAC episode. The optic disc appears edematous during this crisis, and pallor with or without cupping may develop after remission. Many studies report a poor long-term visual outcome after APAC, with high rates of severe glaucomatous optic neuropathy.1-5 Retinal nerve fiber layer (RNFL) loss,6–13 optic nerve head (ONH) damage,14-16 and visual field defects17–19 have been described following APAC. However, there are few reports concerning the long-term changes of RNFL and macular thickness in APAC20, none in Brazilians. Furthermore, no data is available for the possible risk factors for the severity of the retinal damage after years of acute attack. DISCUSSION As far as we are aware, this is the first study to investigate changes in the RNFL thickness many years after an episode of APAC. We noticed important visual field loss and significant decrease of the RNFL thickness in all segments of the affected eye in comparison to non-affected fellow eyes. Visual loss after APAC has been documented from as early as a few days after presentation19 to several months after an acute episode.17 Any neuronal damage resulting from APAC is thought to occur rapidly as a result of this acute presentation of the disease associated with an extremely high IOP. Aung T et al 8 studied the RNFL with Scanning Laser Polarimetry (GDx Nerve Fiber Analyzer) of 40 patients with APAC and found a significant decrease of the superior and inferior average RNFL thickness from week 2 to week 16 after the crisis. Fang et al 7 studied the RNFL (Stratus OCT) of 40 patients with unilateral APAC and found an increase of the RNFL thickness immediately after the attack followed by a decrease over time (up to 3 months). Xiu et al 11 found RNFL thickening right after an acute attack, thinning over 6 months. Friedman et al 4 assessed long-term outcomes in fellow eyes of 79 subjects after unilateral APAC. They reported that 80% retained good vision. Cataracts accounted for most of the visual impairment, and 6.5% developed glaucoma with a mean follow-up of 6 years. PURPOSE To assess the long-term changes in peripapillary RNFL thickness and identify possible risk factors for the severity of this loss. FIGURE 1. Spectral domain optical coherence tomography after 1 year and 4 months of the left eye angle closure crisis. FIGURE 2. Spectral domain optical coherence tomography after 8 years and 7 months of the right eye angle closure crisis. METHODS This is a cross-sectional comparative study. Subjects 18 years of age or older with APAC seen at the Glaucoma Service of São Geraldo Hospital were eligible for the study. They were identified from the hospital computerized database and contacted by phone. Subjects who fulfilled the criteria were included. They were submitted to a clinic examination that included an ophthalmic examination, RNFL imaging using spectral-domain optical coherence tomography (SD-OCT), ultrasound biometric assessment, and automated perimetry by means of the Interzeag Octopus 1-2-3 (Haag-Streit AG, Koeniz, Switzerland). APAC eyes were compared with the fellow eyes without previous crisis as controls. CONCLUSIONS We know that our results are limited in order of the small number of cases, however our study is not finished yet. We intend to improve it by including more patients. Apart from that, it was possible to notice that affected APAC eyes have important structural (RNFL loss) and functional (visual field defects) damages many years after the crisis. REFERENCES 1. Douglas GR, Drance SM, Schulzer. The visual field and nerve head in angle-closure glaucoma. Arch Ophthalmol. 1975;93:409–411. 2.Aung T, Friedman D, Chew P, Ang LP, Gazzard G, Lai YF et al. Long-term outcomes in Asians after acute primary angle closure. Ophthalmology 2004; 111(8): 1464–1469. 3. Aung T, Ang L, Chan S, Chew P. Acute primary angleclosure: long-term intraocular pressure outcome in Asian eyes. Am J Ophthalmol 2001; 131(1): 7–12. 4. Friedman DS, Chew PT, Gazzard G, Ang LP, Lai YF, Quigley HA, Seah SK, Aung T. Long-term outcomes in fellow eyes after acute primary angle closure in the contralateral eye. Ophthalmology. 2006;113(7):1087-91. 5. Tan AM, Loon SC, Chew PT. Outcomes following acute primary angle closure in an Asian population. Clin Experiment Ophthalmol. 2009;37(5):467-72. 6. Tsai J, Chang H. Scanning laser polarimetry in patients with acute angle-closure glaucoma. Eye 2004; 18(1): 9–14. 7. Fang A, Qu J, Li L, Ji B. Measurement of retinal nerve fiber layer in primary acute angle closure glaucoma by optical coherence tomography. J Glaucoma 2007; 16(2): 178–184. 8. Aung T, Husain R, Gazzard G, Chan YH, Devereux JG, Hoh ST et al. Changes in retinal nerve fiber layer thickness after acute primary angle closure. Ophthalmology 2004; 111(8): 1475–1479. 9. Mansoori T, Viswanath K, Balakrishna N Quantification of Retinal Nerve Fiber Layer Thickness After Unilateral Acute Primary Angle Closure in Asian Indian Eyes. J Glaucoma. 2011 Sep 22. [Epub ahead of print] 10. Wong IY, Yuen NS, Chan CW. Retinal nerve fiber layer thickness after a single attack of primary acute angle-closure glaucoma measured with optical coherence tomography. Ophthalmic Surg Lasers Imaging. 2010 Jan-Feb;41(1):96-9. 11.Liu X, Li M, Zhong YM, Xiao H, Huang JJ, Kong XY. Damage patterns of retinal nerve fiber layer in acute and chronic intraocular pressure elevation in primary angle closure glaucoma. Int J Ophthalmol. 2010;3(2):152-7. 12. Tsai JC, Lin PW, Teng MC, Lai IC. Longitudinal changes in retinal nerve fiber layer thickness after acute primary angle closure measured with optical coherence tomography. Invest Ophthalmol Vis Sci. 2007;48(4):1659-64. 13. Tsai JC. Optical coherence tomography measurement of retinal nerve fiber layer after acute primary angle closure with normal visual field. Am J Ophthalmol. 2006;141(5):970-2. 14. Uhm K, Lee J, Sung H. Comparison of glaucomatous optic nerve damage in primary angle-closure glaucoma with and without acute attack. Korean J Ophthalmol 2005; 19(3): 201–207. 15. Shen S, Baskaran M, Fong A, Chan YH, Lim LS, Husain R et al. Changes in the optic disc after acute primary angle closure. Ophthalmology 2006; 113(6): 924–929. 16. Chew SS, Vasudevan S, Patel HY, Gurria LU, Kerr NM, Gamble G, Crowston JG, Danesh-Meyer HV. Acute primary angle closure attack does not cause an increased cup-to-disc ratio.Ophthalmology. 2011 Feb;118(2):254-9. 17. Aung T, Looi A, Chew P. The visual field following acute primary angle closure. Acta Ophthalmol Scand 2001; 79(3): 298–300. 18. Ang L, Aung T, Chua W, Yip L, Chew P. Visual field loss from primary angle-closure glaucoma: a comparative study of symptomatic and asymptomatic disease. Ophthalmology 2004; 111(9): 1636–1640. 19. Bonomi L, Marraffa M, Marchini G, Canali N. Perimetric defects after a single acute angle-closure glaucoma attack. Graefes Arch Clin Exp Ophthalmol 1999; 237(11): 908–914. 20. Sng CC, See JS, Ngo CS, Singh M, Chan YH, Aquino MC, Tan AM, Shabana N, Chew PT. Changes in retinal nerve fibre layer, optic nerve head morphology, and visual field after acute primary angle closure. Eye (Lond). 2011;25(5):619-25. Commercial Relationships: Rafael Mérula, None; Sebastião Cronemberger, None; Érica de Abreu Borges, None; Nassim Calixto, None • Support: None RESULTS The nine patients who were evaluated in this study had an APAC acute crisis ≥ 1 year from the base exam, varying from 1 to 23 years (7.2±6.9 years). They had the following profile; mean age of 67.9 (±8.7) years, 67% women, 77.8% leukodermic, and 100% had a bilateral iridectomy. The average time between the beginning of the symptoms and the lowering of intraocular pressure was 58.8 (±105.5) hours. Table 1 shows intraocular pressure (IOP), axial length (AL), central corneal thickness (CCT), visual field mean defect (MD) and corrected low variance (CLV) of the affected and non-affected fellow APAC eyes. Table 2 shows the RNFL thickness studied by SD-OCT. FIGURE 3. Spectral domain optical coherence tomography after 23 years and 74 months of the right eye angle closure crisis. TABLE 2. Measurements of the retinal nerve fiber layer thickness of affected and fellow non-affected eyes. Affected eyes Non-affected fellow eyes Mean (SD) Global (µm) 74.5 (43.1) 102.0 (3.6) Inferior nasal (µm) 67.4 (32.5) 121.5 (44.6) Inferior temporal (µm) 85.9 (39.8) 141.0 (17.1) Superior nasal (µm) 74.3 (38.0) 108.5 (12.6) Superior temporal (µm) 77.7 (35.4) 132.7 (21.8) Nasal (µm) 57.5 (19.6) 76.3 (20.1) Temporal (µm) 51.0 (9.2) 69.7 (12.7) TABLE 1. Intraocular pressure (IOP) mean at the moment of the crisis, mean central corneal thickness (CCT) and axial length (AL), average visual mean defect (MD), and corrected low variance (CLV) of affected and fellow non-affected eyes. Affected eyes Non-affected fellow eyes Mean (SD) IOP (mmHg) 49.7 (8.3) 12.4 (0.5) AL (mm) 21.79 (0,79) 21.56 (0.32) CCT (µm) 538 (26.3) 537 (19.3) MD 12.2 (8.9) 3.15 (2.9) CLV 24.4 (21.8) 18.6 (18.9) SD = standard deviation. rafaelmerula@hotmail.com SD = standard deviation.