Vasiliki Zygoura

Retained Lens Fragments After Cataract Surgery: Outcomes Of Same-Day vs Later Pars Plana Vitrectomy

WE READ WITH GREAT INTEREST THE RECENT ARTICLE BY Modi and associates about the important and still controversial topic concerning the timing of pars plana vitrectomy for the management of nucleus drop. The authors reported on a large case series of patients surgically treated at their institution for retained lens fragments, analyzing the visual outcomes and the rates of adverse events. We noticed that the authors used the corrected distance visual acuity at final follow-up for the analysis; given that there were some patients who were left aphakic, did the authors consider the visual acuity following the intraocular lens implantation performed in a further surgery, or were those cases excluded from the analysis? We also observed that the authors pointed out how the correct timing of pars plana vitrectomy in these cases had remained controversial prior to their study. Respectfully, we highlight that their report unfortunately still does not provide definitive evidence, although they performed an analysis on a large sample. In fact, the authors might want to clarify the inclusion criteria adopted: did they operate on patients with dropped nucleus fragments smaller than a quarter of lens size or with epinucleus material retained in the vitreous cavity? If that was the case, were these patients with small fragments equally distributed among the 3 study groups? And can the authors analyze whether outcomes and complications were different in relation to the sizes and densities of the dropped lens material? For the delayed intervention, did the authors also base the indication for surgery on clinical conditions, such as excessive intraocular inflammation, elevated intraocular pressure, occurrence of cystoid macular edema, or decreased visual acuity? In addition, it is not clear whether the patients in the groups with delayed pars plana vitrectomy had received specific medical treatments prior to surgery. Finally, it might be of interest to analyze whether there was any difference in the lengths of follow-up needed in cases undergoing immediate vs delayed vitreoretinal intervention.

Hydroimplantation of intraocular lenses

using the Camellin formula when the patient clinical history is unknown. With the Camellin formula, it is possible to calculate the radius of curvature of the posterior corneal surface based on the measurement of the curvature radius of the anterior corneal surface, corneal pachymetry, and a series of pachymetry measurements performed in a 3.0 mm circular zone. It then is possible to obtain the relative keratometric refractive index without knowing the surgically induced refractive change. Therefore, unless we have misunderstood this, the Camellin–Calossi formula does not always require preoperative data.d Megumi Saiki, PhD, Kazuno Negishi, MD, Naoko Kato, MD, Rika Ogino, Hiroyuki Arai, MD, Ikuko Toda, MD, Murat Dogru, MD, Kazuo Tsubota, MD

Endophthalmitis isolates and antibiotic susceptibilities: a 10-year review of culture-proven cases.

1. Ramasubramanian A, Kytasty C, Meadows AT, Shields JA, Leahey A, Shields CL. Incidence of pineal gland cyst and pineoblastoma in children with retinoblastoma during the chemoreduction era. Am J Ophthalmol 2013;156(4):825–829.e2. 2. Moll AC, Imhof SM, Bouter LM, et al. Second primary tumors in patients with hereditary retinoblastoma: a register-based follow-up study, 1945-1994. Int J Cancer 1996;67(4):515–519. 3. Meadows AT, Leahey AM. More about second cancers in retinoblastoma [invited editorial]. J Natl Cancer Inst 2008; 100(24):1743–1745.

Pseudophakic endophthalmitis and the validity of different prophylactic regimens

Pseudophakic endophthalmitis and the validity of different prophylactic regimens We readwith great interest the recent paper byNentwich et al. that refers topostoperative endophthalmitis, a most feared complication of cataract surgery. The authors concluded, “The finding that the risk for postoperative endophthalmitis decreased from period 2 to period 3 in the present study indicates that copious irrigation of the conjunctival fornix is more effective than a few drops of povidone–iodine in reducing the risk for endophthalmitis.” They also added that “intracameral antibiotics might not be necessary but.the preoperative use of povidone–iodine and state-ofthe-art small-incision cataract surgery are.” Although this remains a possibility, we respectfully raise concerns regarding the overall study methodology that was adopted. As the authors noted, “[T]hese results might be confounded by factors apart from changes in the preoperative prophylaxis protocol, such as themodification of surgical techniques.”Needless to say, surgical instrumentations and techniques have dramatically evolved over the past 2 decades, and it might well be the case that the changes in the observed pseudophakic endophthalmitis rates were completely independent from their modified protocol regarding the preoperative use of povidone–iodine. Although retrospective in nature, studies should not be exempted from applying rigorous selection criteria that would enhance the scientific value of their findings and considerably limit the effect of confounding variables. With a view toward focusing more on pseudophakic endophthalmitis after “state-of-the-art small-incision cataract surgery,” we would challenge the authors to agree that further analyses are required. We suggest excluding from new analyses the first period (which refers to only 3 years and 2662 lens surgery procedures) and all cases that might have been at an increased risk for endophthalmitis, such as eyes that have had planned or unplannedmanual extracapsular cataract surgery or combined intraocular surgical procedures, those operated on by surgeons in training or low-volume cataract surgeons, and those having major intraoperative complications such as posterior capsule rupture with or without vitreous loss. In addition, we would also suggest providing information regarding the wound size and location (limbus or in clear cornea) and postoperative status (sutureless versus sutured). In fact, we argue that only after controlling for all these variables can the authors test their hypothesis. Details of the postoperative treatment regimen and instructions received by patients and the possible changes during the study period would also be of interest. Last, we note that intracameral antibiotics are intended to be used in cataract surgery only. Also, we found it difficult to read the figures provided because they weremixedwith the rates of endophthalmitis secondary to surgical procedures other than cataract surgery; hence, we would ask why data on all postoperative endophthalmitis cases observed at the authors’ institution were provided. The authors reported on 68 323 intraocular surgical procedures, although only less than 40% (24 034 eyes) had cataract surgery during the 20-year study period.

Ophthalmic viscosurgical device choice in intumescent cataract.

Ophthalmic viscosurgical device choice in intumescent cataract We read with interest the recent article by Hengerer et al. concerning the use of an ophthalmic viscosurgical device (OVD) in intumescent cataracts in which they pointed out how the internal liquefaction determines increased intracapsular pressure and might lead to complications at the time of capsulorhexis. We certainly agree that performing a complete capsulorhexis remains one of the most important surgical steps in cataract surgery, given the association with intraoperative and postoperative complications and the possible need for unplanned additional surgical intervention. However, we would draw the readers attention to 2 main aspects; that is, needle-bore gauge and OVDs used by the single surgeon who operated on all cases in the reported series. In fact, although the choice might have been appropriate for the surgeons surgical expertise, the authors might agree that a different choice would enhance the safety of the procedure. In Group 1, the adopted medium-viscosity OVD (Healon 1.0%) is unfortunately unable to offer adequate resistance to the high intralenticular pressure encountered in intumescent cataracts; hence, the 10% rate of anterior capsule tear should not be a surprise in these circumstances, and with an insufficient anterior capsule tamponading effect, an anterior capsule tear might frequently occur and the classic Argentinian flag sign might be more the result of an OVD choice error than just a coincidence. In addition, the needle bore used (a bent 19-gauge needle) is too wide and hard to maneuver through the main incision, and the authors used it through an even smaller incision (a side port?). To note, the wound size corresponding to 19-gauge needle exceeds 1.2 mm. In Group 2, the authors used a combination of a high-viscosity OVD (Healon5) and the mediumviscosity OVD (Healon 1.0%), albeit the theoretical advantage of this particular combination remained unexplained. We support the use of a bent 30-gauge needle (or alternatively a bent 27-gauge needle) as a cystotome in intumescent cataracts because it can be easily maneuvered through side-port or main incisions while protecting against the risk for OVD egress and anterior chamber decompression. In addition, surgeons might opt to mount the cystotome needle on the OVD syringe, which allows further injection of additional OVD without reentering the anterior chamber, if need be. We also suggest performing a complete needle capsulorhexis without a forceps, if possible.

Comment on: Refractive outcome analyses in myopes

Dear Editor, We read with great interest the recent article from Mitra et al. on refractive outcomes in myopes.[1] The main purpose of their work was to investigate the refractive accuracy of some of the currently available intraocular lens (IOL) calculation formulas for the prediction of the required lens power. We noted that they included only eyes implanted with the same IOL in the capsular bag. However, there is a number of points that we would like to point out. The size of the sample that was investigated in this study was limited (only 43 eyes), and testing for normality of the distribution should have been performed. We also raise criticism in relation to the large range of axial lengths included (24.75–32.35 mm): In this way, the authors included eyes with moderate, high and extreme myopia in the same sample. It is well-known that the IOL power prediction formula estimate the effective lens position in relation to the axial length and average corneal power, and notoriously perform worse in eyes with very long axial length. In addition, formulas might work unpredictably when abnormal corneal powers are involved, as in a fifth of the enrolled eyes. We would like to challenge the authors to agree that these limitations should be kept in mind by the readers, as might have potentially interfered with the study results. Perhaps the authors might provide the readership with graphs displaying the relation between absolute errors and axial length with the different formulas tested. Lastly, it was not clear why the authors used the mean numerical error as opposed to the mean absolute error for their analyses.

Clinical Outcomes in the First Two Years of Femtosecond Laser-Assisted Cataract Surgery.

PURPOSE: To analyze outcomes of femtosecond laser cataract surgery cases in the first 2 years in an ophthalmic institution. DESIGN: Nonrandomized treatment comparison with matched, historical controls. METHODS: Outcomes and intraoperative events of all laser cataract surgeries (5.0to 5.5-mm-diameter laser capsulotomies and nuclear fragmentation) at the Singapore National Eye Centre (May 2012–December 2013) were prospectively audited. The 6-weekspostoperative unaided visual acuities (UAVA), mean absolute error (MAE), mean square error (MSE), and manifest refraction spherical equivalent (MRSE) results of surgeons with >50 laser cases were compared with controls, a random sample of manual cases with similar age, axial length, and preoperative cylinders. Statistical analysis was performed with SPSS (P < .05). RESULTS: A total of 1105 eyes (803 patients) underwent laser cataract surgery by 18 surgeons. The majority were female (56.9%) and Chinese (90.9%) with mean age 66.1 ± 11.0 years. Intraoperative complications were subconjunctival hemorrhage (290, 26.2%), anterior capsule tear (9 eyes, 0.81%), posterior capsule rupture (3 eyes, 0.27%), suction loss (5 eyes, 0.45%), iris hemorrhage (1 eye, 0.09%), and endothelial incision (1 eye, 0.09%). There was no dropped nucleus. Visual outcomes of 794 laser surgeries were compared to 420 controls. The %UAVA 20/25 or better was higher in laser cases (68.6% vs 56.3%; P < .0001) but MAE (0.30 ± 0.25 diopter [D] vs 0.33 ± 0.25; P [ .062) and MSE (0.16 ± 0.27 D vs 0.17 ± 0.28 D; P [ .065) were not significant. MRSE comparison was significant (target plano, preoperative cylinder <1.5 D L0.08 ± 0.36 D vs L0.13 ± 0.40 D; P [ .034). CONCLUSIONS: Femtosecond laser cataract surgery has a low complication rate. Cases compared to controls had statistically better %UAVA £20/25 and

Intraocular lens optic capture and zonular impairment.

dioptric amount of astigmatism treated in minus cylinder, as in our figure. On the doubled-angle plot for this surgery, the left side of the x-axis would be the removal of with-the-rule (WTR) astigmatism and the right side of the x-axis, the removal of against-the-rule (ATR) (not nasal–temporal). The superior y-axis is the removal of oblique astigmatism in the 45degree meridian and the inferior y-axis, the removal of oblique astigmatism in the 135-degree meridian (not superior–inferior meridian). Our comments would apply to the intended refraction correction in their Figure 1 as well as the error vector plots in Figures 2 and 3. The only time one uses the signed x and y Cartesian coordinates is for the computation of the standard deviations and centroid, as they have done correctly. Because most young patients had WTR astigmatism, the centroid of the intended refractive correction would be as shown on the left side of the x-axis, indicating that WTR was the predominant astigmatism and was more prevalent than either ATR or oblique astigmatism, which was equally balanced between the 45-degree and 135-degree meridians. This correction does not change their results but does change the comparison of meridians being discussed and is a very important clarification in the interpretation of doubled-angle plots.

Refractive outcomes in pseudoexfoliation syndrome

Reply : Dr. Galvis et al. wrote that the coefficient of determination (R) of 0.73 for the regression equation between the preoperative mean anterior K values in the 3.0 mm zone (Km) and the postoperative mean posterior corneal power in the 6.0 mm zone (K) in 72 post-LASIK eyes does not guarantee that the model fits the data sufficiently well, because a high R can occur in the presence of a misspecified functional form of a relationship or in the presence of outliers that distort the true relationship. However, as shown in Figure 1 in our article, the relationship between the 2 variables in our study was linear and included no outliers, meeting the major assumptions for simple linear regression analysis. Therefore, we believe the simple linear regression model is an appropriate functional form for the data and the parameter estimates are unbiased. Second, we want to confirm that the constants a0, a1, and a2 for the Haigis-L method and the constant SF constant for the Holladay formula recommended

Intraocular lens power selection and optic capture.

Intraocular lens power selection and optic capture We fully agree with Millar et al. about the importance of preserving an intact capsulorhexis in cases of complicated cataract surgery, which should be appropriately sized and centered to enable lens optic capture. We previously highlighted the problems related to intraocular lens (IOL) power selection when this technique is used and suggested leaving the IOL power unadjusted (using the same IOL power selected for in-the-bag IOL fixation). Therefore, we commend the authors for the good results observed in their series and for investigating this subject for the first time and in a single-surgeon retrospective study. Although their study was in line with our experience, the evidence provided should not be considered conclusive in view of several study limitations. Besides the small number of eyes with optic capture (24), the effect of some of the collected variables that could have an impact on the final refraction was not analyzed, particularly the anterior chamber depth and the average corneal power. In addition, the IOL power prediction formula and IOL constants were not detailed and it might be more appropriate to investigate the results with only 1 of the IOLs, given the differences in terms of manufacturer A constant (118.4 versus 118.9) and anterior optic profile (ie, the Acrysof MA50BM IOL is not anteriorly asymmetric). We wonder whether the authors are able to provide the results observed with the Acrysof MA60AC IOL alone, which is more widely implanted. Additional variables might be the type of refraction (manual or automated) and the reported possibility that in some eyes, the optic capture was lost postoperatively. In a recent multi-surgeon audit at our institution, we observed that only a fifth of the sulcus-fixated IOLs (12/54) implanted following posterior capsule rupture had optic capture (all cases implanted with the Acrysof MA60AC). In these cases, the refractive outcomes were more accurate, with 91% of eyes within 1.0 diopter (D) of target and a mean absolute error of 0.40 D G 0.27 (SD) (range 0.03 to 1.07 D). For this reason, and for the expected lower rates of IOL decentration/dislocation and iris chafing, we favor the use of this technique whenever possible. Finally, capsular distension syndrome cannot intervene when this technique is used in cases with posterior capsule rupture; accordingly, the 2 papers cited by Millar et al. described cases with intact posterior capsules, which were managed with neodymium: YAG laser capsulotomy.