Eyeworld

EW RESIDENTS 58 December 2018 or discontinuities and "dehiscent" if the contrary was true. All patients had their cataracts removed by a single, experienced surgeon who was masked to the AS-OCT findings. Of the 64 eyes enrolled in the study, eight eyes (12.5%) showed dehiscent PC on AS-OCT, of which five (7.8%) showed intraopera- tive PC dehiscence, one of which required pars plana vitrectomy. The three eyes that showed dehiscence on imaging but not intraoperative- ly were found on review to have a dense plaque causing artifact in one eye and multiple minute areas of PC deficits that caused an interpre- tation of dehiscence. No eyes had intraoperative PC dehiscence that were not detected on AS-OCT. Based on the above results, AS-OCT was determined to carry the following statistical markers for detecting pos- terior capsular dehiscence: sensitivi- ty 100%, specificity 94.9%, positive predictive value 62.50%, and nega- tive predictive value 100%. This paper's strengths include its prospective nature, large sample size, and use of a single surgeon who was masked to the imaging results. The determination of PC dehiscence was objective and reproducible, though only a single observer was used. In most cases, the authors were able to directly correlate the imaging findings (PC dehiscence) to their intraoperative findings. The high negative predictive value (100%) makes AS-OCT clinically use- ful in helping clinicians risk stratify their patients with PPC. Interestingly, 27.5% of the eyes that showed PC dehiscence on AS- OCT did not show intraoperative PC dehiscence. While these numbers were low and still led to excellent specificity, two of the eyes that were falsely read as having PC dehiscence still likely had very thin posterior capsules, which the cataract surgeon may want to be aware of preopera- tively. Some factors may limit the gen- eralizability of this study, which ex- cluded both PPC less than 4 mm in diameter as well as denser cataracts. Older studies have demonstrated that PPCs larger than 4 mm were an independent risk factor. 10 Further, increased optical density caused one false positive reading on AS-OCT; evaluating whether denser nuclear cataracts could also contribute to false negatives is therefore import- ant. Additionally, a distinction between the different morphologies of PPC (such as stationary vs. pro- gressive PPC) was not made in this study, nor whether their behavior is the same under AS-OCT. In summary, this study effec- tively demonstrates the utility of AS-OCT in assessing the integrity of the posterior capsule in PPC with a high negative predictive value. Further areas of interest include exploring whether knowledge of PC dehiscence by AS-OCT preoperative- ly can significantly aid the surgeon in avoiding need for vitrectomy, as occurred in one case for the blinded study surgeon. Additionally, a future study could track whether PC dehis- cence evolves over time in PPC. If that were the case, it could inform argument for early PPC extraction to prevent intraoperative complica- tions. Regardless, using this study's results, AS-OCT can more confident- ly be used to tailor risk counseling patients with PPC preoperatively. EW References 1. Kalantan H. Posterior polar cataract: A review. Saudi J Ophthalmol. 2012;26:41–9. 2. Addison PK, et al. Posterior polar cataract is the predominant consequence of a recurrent mutation in the PITX3 gene. Br J Ophthalmol. 2005;89:138–41. 3. Yamada K, et al. Genetically distinct autosomal dominant posterior polar cataract in a four-generation Japanese family. Am J Ophthalmol. 2000;129:159–65. 4. Tulloh CG. Hereditary posterior polar cata- ract with report of a pedigree. Br J Ophthal- mol. 1955;39:374–9. 5. Ionides AC, et al. A locus for autosomal dominant posterior polar cataract on chromo- some 1p. Hum Mol Genet. 1997;6:47–51. 6. Bidinost C, et al. Heterozygous and homozygous mutations in PITX3 in a large Lebanese family with posterior polar cataracts and neurodevelopmental abnormalities. Invest Ophthalmol Vis Sci. 2006;47:1274–80. 7. Berry V, et al. Alpha-B crystallin gene (CRYAB) mutation causes dominant congenital posterior polar cataract in humans. Am J Hum Genet. 2001;69:1141–5. 8. Liu M, et al. Identification of a CRYAB mutation associated with autosomal dominant posterior polar cataract in a Chinese family. Invest Ophthalmol Vis Sci. 2006;47:3461–6. 9. Osher RH, et al. Posterior polar cataracts: a predisposition to intraoperative posterior capsular rupture. J Cataract Refractive Surg. 1990;16:157–62. 10. Ionides A, et al. Visual outcome following posterior capsule rupture during cataract surgery. Br J Ophthalmol. 2001;85:222–4. 11. Kapoor CG, et al. Posterior polar cataract: Minimizing risks. Med J Armed Forces India. 2016;72:242–6. Contact information Chow: jessica.chow@yale.edu Review continued from page 56 Can preoperative anterior segment optical coherence tomography predict posterior capsule rupture during phacoemulsification in patients with posterior polar cataract? Gurudatha Pavan Kumar, DNB, Palaniswamy Krishnamurthy, MS, Manas Nath, DO, Prabu Baskaran, MS, Muralikrishnan Janani, DNB, Rengaraj Venkatesh, DNB J Cataract Refract Surg. 2018;44(12):1441–1445. Purpose: To understand if preoperative assessment of posterior capsule integrity using anterior segment optical coherence tomography (AS- OCT) can predict posterior capsule dehiscence in patients with posterior polar cataract (PPC) undergoing phacoemulsification. Setting: Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Pondicherry, India Design: Prospective observational study Methods: Eyes with PPC that underwent phacoemulsification were included in the study during the period between October 2012 and November 2013. Preoperative AS-OCT imaging was performed to assess the integrity of the posterior capsule. AS-OCT images of the posterior capsule were graded as "intact" or "dehiscent." Phacoemulsification was performed by a single surgeon who was masked from AS-OCT findings. The integrity of the posterior capsule was evaluated by the surgeon intraoperatively. Results: The study involved 64 eyes of 62 patients. Preoperative AS-OCT showed 8 (12.5%) eyes to have probable posterior capsular dehiscence and 56 (87.5%) eyes to have intact posterior capsule. Intraoperatively the surgeon noted posterior capsular dehiscence in 5 (7.8%) eyes and an intact posterior capsule in 59 (92.2%) eyes. The sensitivity and specificity of AS-OCT for detecting posterior capsular dehiscence was 100% and 94.92%, respectively. The negative predictive value of AS- OCT was 100%. Conclusion: Anterior segment OCT with its high negative predictive value can be successfully utilized to predict the risk of posterior capsule rupture during phacoemulsification in eyes with PPC.

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