LETTERS TO THE EDITOR RE: Ultrachopper tip Dear Editor, We read with interest the article by Barlow et al. 1 on the Ultrachopper tip (Alcon Inc, Fort Worth, TX) device that was developed by one of us (L.J.E.). We were pleased to read that the clinical experience of the authors supports that it is useful in assist chopping, both in routine and very dense cataracts. Many surgeons have replicated that experience. In our centre, we have found that techniques using the Ultrachopper are easy to teach, and the young surgeons find them very valuable. In our clinical experience, we have found that it is not necessary to use torsional power with the Ultrachopper, and using only longitudinal power (30%–50%, preferably pulsed), the amount of heat transferred to the incision will diminish. In Figure 1 in the article, 1 it is evident that when using BSS, even 25 seconds after activating position 3 in the foot pedal, temperature reached around 301C, well below 441C, which experimentally has been found to be the threshold to cause a corneal burn. 2 We always recommend using first aspiration with the Ultrachopper, to remove cortex, along with the OVD, and leaving only BSS in the proximity of the aspiration ports. In 4þ cataracts, we advise using “divide and conquer” techniques with the Ultrachopper, first making the grooves, which is a very easy and rapid task with the Ultrachopper, and then completing the nuclear fracture with a mechanical prechopper (v.gr. Escaf Prechopper, ASICO AE-4295). CDE should not exceed 8 to 12 units, and “on” time with the Ultrachopper for each groove is not more than 2 to 4 seconds. In extremely hard cataracts, we recommend using a nucleus sustainer placed at the equator of the lens to exert counter-pressure to the cutting motion of the Ultrachop- per. In this way, 4 to 6 fragments of the nucleus can be easily obtained, using CDE of around 2 to 3 units. We advise never to use the Ultrachopper continuously “on” for more than 2 to 4 seconds. Following these recommendations, it is very improbable to cause a wound thermal burn. Luis J. Escaf, Juanita Londoño, Luz M. Melo Clı ´nica Oftalmolo ´gica del Caribe, Barranquilla, Colombia Correspondence to: Luis J. Escaf: luisescaf99@hotmail.com REFERENCES 1. Barlow WR Jr, Pettey J, Olson RJ. The Ultrachopper tip: a wound temperature study. Can J Ophthalmol. 2013;48:512-5. 2. Ernest P, Rhem M, McDermott M, et al. Phacoemulsification conditions resulting in thermal wound injury. J Cataract Refract Surg. 2001;27:1829-39. Can J Ophthalmol 2014;49:307 0008-4182/14/$-see front matter & 2014 Published by Elsevier Inc on behalf of the Canadian Ophthalmological Society. http://dx.doi.org/10.1016/j.jcjo.2014.03.017 RE: Microperimetry and the diagnosis of antimalarial maculopathy Dear Editor, I read with interest the recent article “Use of Microperi- metry to Evaluate Hydroxychloroquine and Chloroquine Retinal Toxicity” by Martinez-Costa et al. 1 The authors conclude that microperimetry is a good test to detect early and subtle functional impairment caused by chloroquine and hydroxychloroquine. I wonder if this is really the case. In this article, there were 7 patients with probable maculopathy. The authors define probable maculopathy as “a pericentral scotoma with Z3 adjacent points between 2 and 3 SDs from the normal average and/or Z2 adjacent points with a sensitivity beyond 3 SDs from the normal average.” We don’t classify a patient as having probable maculopathy unless we can demonstrate many relative reproducible scotomas in both eyes. Of the 10 patients with definite retinopathy, 4 had advanced bull’s-eye maculopathy. The other 6 patients had only subtle sectorial depigmentation of the macular area. Did these patients have bilateral paracentral scoto- mas; that is, did they have definite retinopathy? In the advanced cases of antimalarial retinopathy, all modalities are positive, that is, fundus changes, fluorescein changes, OCT, and multifocal electroretinogram (mfERG). It is the very early cases with bilateral, reproducible, shallow scotomas found on perimetry for whom we need objective tests to confirm the diagnosis of maculopathy. The revised recommendations for screening published by the American Academy of Ophthalmology in 2011 stressed the usefulness of objective tests such as mfERG, autofluorescence, and OCT. 2 However, only 6 of our 18 patients with early antimalarial maculopathy (bilateral, reproducible, shallow scotomas) showed changes by auto- fluoresence and OCT by 2 modalities (Heidelberg and Zeiss), suggesting these tests at present are not sensitive enough. 3 All patients demonstrated depression in ampli- tude with the mfERG. Is this test too sensitive? Could patients without field defects be showing changes with the mfERG? 4