Unusual presentation of angle-closure glaucoma treated by phacoemulsification

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the OCT in an albino eye.8 We demonstrated that for 10 diopters of accommodation, the reduction in the ciliary diameter was almost 1.0 mm. This is a major point concerning posterior chamber phakic IOLs to be implanted in the sulcus. Which is the correct diameter to consider in a young patientdvertical, horizontal, accommodated, unaccommodated? We have to consider that a 25-year-old subject will accommodate billions of times in the decades following implantation and the ciliary body will exert pressure on the IOL a billion times. To conclude, it was not my intention to discredit the Artemis, but if one compares the advantages of the Visante OCT and the Artemis in daily practice, I sincerely believe the Visante OCT is simpler to use and as mentioned in your article, the problems concerning reproducibility implicitly demonstrate that the Artemis’ technique is not as straightforward and is relatively time consuming. Only time will tell which of the 2 will have the most promising future in routine practice.dGeorges Ba€l koff, MD

REFERENCES 1. Baı¨koff G, Bourgeon G, Jodai HJ, et al. Evaluation of the measurement of the anterior chamber’s internal diameter and depth: IOLMaster vs anterior chamber optical coherence tomography. In press, J Cataract Refract Surg 2. Baı¨koff G, Lutun E, Ferraz C, Wei J. Static and dynamic analysis of the anterior segment with optical coherence tomography. J Cataract Refract Surg 2004; 30:1843–1850 3. Foster P, Alsbirk PH, Baasanhu J, et al. Anterior chamber depth in Mongolians: variation with age, sex and method of measurement. Am J Ophthalmol 1997; 124:53–60 4. Rondeau MJ, Barcsay G, Silverman RH, et al. High frequency ultrasound biometry of the anterior and posterior chamber diameter. J Refract Surg 2004; 20:454–464 5. Baı¨koff G, Bourgeon G, Jodai HJ, et al. Pigment dispersion after Artisan phakic intraocular lens: crystalline lens rise as a safety criterion. J Cataract Refract Surg 2005; 31:674–680 6. Baı¨koff G, Lutun E, Wei J, Ferraz C. Contact between 3 phakic intraocular lens models and the crystalline lens: an anterior chamber optical coherence tomography study. J Cataract Refract Surg 2004; 30:2007–2012 7. Kim DY, Reinstein DZ, Silverman RH, et al. Very high frequency ultrasound analysis of a new phakic posterior chamber intraocular lens in situ. Am J Ophthalmol 1998; 125:725–729 8. Baı¨koff G, Lutun E, Wei J, Ferraz C. Anterior chamber optical coherence tomography: study of human natural accommodation in a 19-year-old Albino. J Cataract Refract Surg 2004; 30:696–701

Unusual presentation of angle-closure glaucoma treated by phacoemulsification We would like to comment on the case report by Wang and Lai.1 In any eye with a history of acute angle closure and persistent appositional angle closure despite a patent iridotomy, plateau iris syndrome is a common cause of elevated intraocular pressure (IOP), whether chronic or acute.2–8 Plateau iris syndrome is, in fact, not uncommon in Chinese eyes. An ultrasound biomicroscopic study of Chinese eyes with a history of acute angle closure and a patent iridotomy at our center revealed that 55.6% of the

eyes had persistent appositional angle closure secondary to plateau iris configuration (unpublished data). In the presence of appositional angle closure secondary to plateau iris, argon laser peripheral iridoplasty (ALPI)9–11 can be considered. This technique has been effective in reopening the drainage angle, controlling IOP, and preventing recurrent acute attacks in plateau iris syndrome in the long term.12 We would like to know whether there were gonioscopic (eg, double-hump sign) or ultrasound biomicroscopic signs of plateau iris syndrome in this patient during the 9-year follow-up before the second acute attack. Argon laser peripheral iridotomy may, at least conceptually, also be effective in situations of appositional angle closure caused by other mechanisms such as angle crowding, although direct evidence is lacking. Merely observing an appositionally closed angle in an eye with previous acute angle closure and a patent iridotomy may result in recurrent acute angle closure (as evidenced by this case report) or progression to the chronic form of angle-closure glaucoma. Once the recurrent attack has occurred, ALPI may be the best treatment option to rapidly and safely control IOP and reopen the appositionally closed angle.13 We agree with the authors that lens extraction may have a beneficial effect in eyes with angle-closure glaucoma. However, the best timing for phacoemulsification in a patient with a recent acute angle closure has not been determined. It would be undesirable to perform phacoemusification if the eye were congested, the cornea edematous, and the pupil unable to be well dilated. Together with the shallow anterior chamber depth, the overall intraoperative risk will be higher. The patient can also be highly sensitized to pain, probably as a result of recent inflammation. Topical anesthesia may not be a good choice in such eyes. Excessive and exaggerated postoperative anterior chamber inflammation can occur, and intraoperative subconjunctival steroid injection would be helpful. We are interested to know whether the authors encounter similar difficulties during phacoemulsification and also whether there was significant anterior chamber reaction postoperatively. Safety is our primary concern when performing cataract extraction in an eye shortly after acute angle closure. The actual benefits and risks of early phacoemulsification in acute angle-closure eyes and the best timing for such interventions should be evaluated in a randomized controlled trial. CLEMENT C.Y. THAM, FRCS, FRCOPHTH(HK) DEXTER Y.L. LEUNG, FRCS JIMMY S.M. LAI, MD, FRCOPHTH DENNIS S.C. LAM, MD, FRCOPHTH Hong Kong, China

REFERENCES 1. Wang J-K, Lai P-C. Unusual presentation of angle-closure glaucoma treated by phacoemulsification. J Cataract Refract Surg 2004; 30: 1371–1373 2. To¨rnquist R. Angle-closure glaucoma in an eye with a plateau type of iris. Acta Ophthalmol 1958; 36:419–423 3. Ritch R. Plateau iris is caused by abnormally positioned ciliary processes. J Glaucoma 1992; 1:23–26 4. Pavlin CJ, Ritch R, Foster FS. Ultrasound biomicroscopy in plateau iris syndrome. Am J Ophthalmol 1992; 113:390–395 5. Godel V, Stein R, Feiler-Ofry V. Angle-closure glaucoma following peripheral iridectomy and mydriasis. Am J Ophthalmol 1968; 65:555–560

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6. Lowe RF. Primary angle-closure glaucoma: postoperative acute glaucoma after phenylephrine eyedrops. Am J Ophthalmol 1968; 65:552– 554 7. Lowe RF. Plateau iris. Aust J Ophthalmol 1981; 9:71–73 8. Wand M, Grant WM, Simmons RJ, Hutchinson BT. Plateau iris syndrome. Trans Am Acad Ophthalmol Otolaryngol 1977; 83:OP122– OP130 9. Ritch R. Techniques of Argon Laser Iridectomy and Iridoplasty. Palo Alto, CA, Coherent Medical Press, 1983 10. Ritch R. Argon laser peripheral iridoplasty: an overview. J Glaucoma 1992; 1:206–213 11. Sassani JW, Ritch R, McCormick S, et al. Histopathology of argon laser peripheral iridoplasty. Ophthalmic Surg 1993; 24:740–745 12. Ritch R, Tham CCY, Lam DSC. Long-term success of argon laser peripheral iridoplasty in the management of plateau iris syndrome. Ophthalmology 2004; 111:104–108 13. Lam DSC, Lai JSM, Tham CCY, et al. Argon laser peripheral iridoplasty versus conventional systemic medical therapy in treatment of acute primary angle-closure glaucoma; a prospective, randomized, controlled trial. Ophthalmology 2002; 109:1591–1596

Reply: A diagnosis of plateau iris syndrome was not likely in this case. The patient had a shallow anterior chamber depth (ACD) (1.93 mm) without a sharp peripheral iris drop-off and a doublehump sign following examination by indentation gonioscopy. Although we did not perform ultrasound biomicroscopy to confirm the configuration of the peripheral iris, the findings did not correlate with the diagnostic criteria for plateau iris. We suggest that this type of appositional angle closure should be categorized as angle crowding, not plateau iris. Plateau iris syndrome was diagnosed in another patient we treated recently who developed acute glaucoma with an appositionally closed angle, normal ACD, a double-hump sign, and a patent iridotomy. The case was also treated successfully with phacoemulsification, and the occludable angle disappeared postoperatively (unpublished case report). We agree that ALPI is effective in treating appositional angle closure (including angle crowding and plateau iris) and preventing recurrent acute attacks. We also perform ALPI in patients with acute angle closure unrelieved by patent iridotomies or poorly medically controlled chronic angle-closure glaucoma. Some respond well to ALPI. However, we did not treat the acute episode in this patient with ALPI for several reasons. Argon laser applications to the peripheral iris in a shallow anterior chamber will result in certain damage of the corneal endothelium. Phacoemulsification also causes limited endothelial loss. If we performed cataract extraction following ALPI, prolonged corneal edema or even corneal decompensation might occur. Although corneal complications caused by ALPI have not been reported in previous studies, clinical results of intraocular surgeries following ALPI were not mentioned. Besides, the patient requested cataract surgery to correct the blurred vision. Modern cataract surgery not only resulted in visual recovery, but also eliminated appositional angle closure to prevent further acute attacks. Because acute glaucoma was detected in this patient within a few hours, medical treatment alone was sufficient to control IOP. Congested conjunctiva, edematous cornea, and anterior chamber inflammation disappeared 3 days after the episode. The patient did not report ocular pain under topical anesthesia during the operation, and the intraocular reaction was not excessive postoperatively. We propose that the duration of the acute attack

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is associated with the timing of future intraocular surgeries and the postoperative reaction of the anterior chamber. If patients have persistent acute angle closure for a longer period, more severe inflamed eyes with more edematous corneas will be found. In such cases, we have to wait longer for the acute signs to disappear to perform the next intraocular intervention. An exaggerated reaction of the anterior chamber following the operation can be expected in these cases.dPei-Ching Lai, MD, Jia-Kang Wang, MD

Axial length and age at cataract surgery Tuft and Bunce1 discuss the proposed association between long axial length (AL) and younger age at the time of cataract surgery. They suggest myopic eyes might be predisposed to earlier surgery because of the cataract. Their proposition, however, contravenes the observation of a Chinese population-based survey by Wong and coauthors2 that the biometric component was not associated with nuclear or cortical cataract types, which made up most of the age-related cataract population. One may wonder whether the ethnic composition of Tuft and Bunce’s data influences the applicability of Wong and coauthors’ findings, but racial difference between Chinese, white, and black is immaterial to ocular biometry, as indicated by Congdon et al.3 The discrepancy may be accounted for by several explanations. First, Wong and coauthors, in the same study, demonstrate a correlation between longer AL and younger age; a mean difference of C0.58 mm was found between the age groups of 40 to 49 years and 70 to 81 years.4 Closer inspection of the data in Tuft and Bunce’s study shows that the cataract surgery group was a highly selective population. Therefore, the authors’ supposition might actually be the reflection of cohort phenomenon that the younger population has a longer AL than the older population. In the study, several confounding factors or variables with known association with ALs were not controlled; ie, sex and adult height.2,5 Being male and tall are important independent predictors for longer ALs.2,5 Moreover, Tuft and Bunce’s method of measuring AL by ultrasound transducer with fixed applanation pressure differs from the recommended methodology4 and may introduce uncontrolled variation in the observers.6 The correlation coefficient in this study is only 0.09, indicating a weak association between early cataract surgery and patients with longer eyes. Therefore, unless all the above factors can be addressed, the inference drawn by the authors may be difficult to be attained with confidence. Perhaps the authors can enlighten us by clarifying the possible confounding influences. DAVID T.L. LIU, MRCS DOROTHY S.P. FAN, FRCS WAI-MAN CHAN, FRCP DENNIS S.C. LAM, MD Hong Kong, China REFERENCES 1. Tuft SJ, Bunce C. Axial length and age at cataract surgery. J Cataract Refract Surg 2004; 30:1045–1048 2. Wong TY, Foster PJ, Johnson GJ, Seah SKL. Refractive errors, axial ocular dimensions, and age-related cataracts: the Tanjong Pagar Survey. Invest Ophthalmol Vis Sci 2003; 44:1479–1485

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