Chris H.L. Lim

LASIK following small incision lenticule extraction (SMILE) lenticule re-implantation: a feasibility study of a novel method for treatment of presbyopia.

Presbyopia remains a major visual impairment for patients, who have previously undergone laser refractive correction and enjoyed unaided distance vision prior to the onset of presbyopia. Corneal stromal volume restoration through small incision lenticule extraction (SMILE) lenticule re-implantation presents an opportunity for restoring the patients’ non-dominant eye to previous low myopia to achieve a monovision. In this study, we investigated the feasibility of performing LASIK after lenticule re-implantation as a method to create presbyopic monovision. A -6.00D SMILE correction was performed in 9 rabbit eyes. The lenticules were cryopreserved for 14 days and re-implanted. Five weeks later, 3 of these eyes underwent LASIK for -5.00D correction (RL group); 3 underwent LASIK flap creation, which was not lifted (RN); and no further procedures were performed on the remaining 3 eyes. These groups were compared with 3 eyes that underwent standard LASIK for a -5.00D correction (LO); 3 that underwent creation of non-lifted flap (LN); and 3 non-operated eyes. Rabbits were euthanized 1 day post-surgery. Tissue responses were analyzed by immunohistochemistry, slit lamp and in vivo confocal microscopy (IVCM). Intrastromal irregularities and elevated reflectivity levels of the excimer-ablated plane were observed on slit lamp and IVCM, respectively in the RL group. The results were comparable (P = 0.310) to IVCM findings in the LO group. RL and LO groups showed similar fibronectin expression levels, number of CD11b-positive cells (P = 0.304) and apoptotic cells (P = 0.198). There was no difference between the RN and LN groups in reflectivity levels (P = 0.627), fibronectin expression levels, CD11b-positive cells (P = 0.135) and apoptotic cells (P = 0.128). LASIK can be performed following lenticule re-implantation to create presbyopic monovision. The tissue responses elicited after performing LASIK on corneas that have undergone SMILE and subsequent lenticule re-implantation are similar to primary procedure.

A Comparative Cohort Study of Visual Outcomes in Femtosecond Laser-Assisted versus Phacoemulsification Cataract Surgery

PURPOSE To evaluate visual outcomes after femtosecond laser-assisted cataract surgery (LCS) with phacoemulsification cataract surgery (PCS). DESIGN Prospective, multicenter, comparative case series. PARTICIPANTS Consecutive patients undergoing femtosecond LCS or PCS with intraocular lens insertion. METHODS A total of 1876 eyes of 1238 patients (422 male and 772 female) who underwent cataract surgery between January 2012 and June 2014 were included in the study: 1017 eyes from center A and 859 eyes from center B. Cases underwent clinico-socioeconomic selection. Patients with absolute LCS contraindications were assigned to PCS; otherwise, all patients were offered LCS and elected on the basis of their decision to pay (the out-of-pocket cost for LCS). Demographic and postoperative data were collected to determine differences between groups. MAIN OUTCOME MEASURES Six-month postoperative visual and refractive outcomes. Masked subjective refractions were performed 2 to 6 months postoperatively. RESULTS There were 988 eyes in the LCS group and 888 eyes in the PCS group. Baseline best-corrected visual acuity (BCVA) was better in LCS compared with PCS (20/44.0 vs. 20/51.5; P < 0.0003). Preoperative surgical refractive aim differed significantly between groups (LCS -0.28 vs. PCS -0.23; P < 0.0001). More patients who received LCS had Toric lenses implanted compared with PCS (47.4% vs. 34.8%; P < 0.0001). Postoperative BCVA was better after LCS (20/24.5 vs. 20/26.4; P = 0.0003) with a greater proportion of LCS cases achieving BCVA >20/30 (LCS 89.7% vs. PCS 84.2%; P = 0.0006) and 20/40 (LCS 96.6% vs. PCS 93.9%; P = 0.0077). However, PCS cases had more letters gained compared with LCS cases (13.5 vs. 12.5 letters; P = 0.0088), reflecting baseline BCVA differences. Mean absolute error was higher in LCS compared with PCS (0.41 diopters [D] vs. 0.35 D; P < 0.0011). The percentage of eyes within 0.5 D of error from preoperative aim refraction was higher in the PCS group (LCS 72.2% vs. PCS 82.6%; P < 0.0001). CONCLUSIONS Femtosecond LCS did not demonstrate clinically meaningful improvements in visual outcomes over conventional PCS.

Risk factors for contact lens-related microbial keratitis in Singapore

Purpose:To investigate independent risk factors for contact lens-related microbial keratitis in Singapore and estimate their impact on disease load.Methods:Cases were contact lens wearers presenting to Singapore National Eye Centre with microbial keratitis between 2008 and 2010. Community contact lens wearers were recruited as controls. All wearers completed a previously validated questionnaire describing contact lens wear history, hygiene and compliance habits, and demographics. Risk factors significant in univariate analysis (P<0.2) were evaluated in a multivariate model.Results:In all, 58 cases of microbial keratitis and 152 contemporaneous controls were identified. When controlling for other variables, Chinese had a 7 × lower risk compared with other races (95% CI: 2.3–21.3, P=0.001). Those aged between 25 and 44 years were at 3 × increased risk compared with younger wearers (95% CI: 1.1–9.6, P=0.04). Occasional overnight contact lens wear (less often than one night per week) was associated with a 4 × higher risk (95% CI: 1.2–15.4, P=0.03) compared with daily use. Not washing hands before handling was associated with a 13 × increased risk (95% CI: 1.9–84.8, P=0.008). Use of multipurpose solution A carried a 16 × higher risk compared with hydrogen peroxide (95% CI: 1.5–174.0, P=0.02). The combined PAR% for modifiable risk factors (occasional overnight wear, not washing of hands, and MPS A) was 82%.Conclusions:Consistent with previous findings, independent risk factors for contact lens-related microbial keratitis include poor hand hygiene, occasional overnight wear, and type of lens care solution. Prolonged overnight or extended contact lens use was infrequent in this population.

Acute intraoperative rock-hard eye syndrome and its management

Purpose To evaluate the use of pars plana needle aspiration of retrolenticular fluid in the immediate management of an acute intraoperative rock‐hard eye syndrome (AIRES). Setting Private practice, Sydney, Australia. Design Retrospective case series. Methods Data over an 18‐month period were collected to evaluate efficacy, complications, and visual outcomes in patients who had pars plana needle aspiration for management of AIRES, which is an acute intraoperative shallowing of the anterior chamber and a marked increase in intraocular pressure (IOP) during phacoemulsification cataract surgery but without evidence of a choroidal hemorrhage. Preoperative and postoperative (1 day, 1 week, and 1 month) data were evaluated. Resolution of AIRES and postoperative posterior segment status, IOP, and corrected distance visual acuity (CDVA) were the main outcome measures. Results Acute intraoperative rock‐hard eye syndrome occurred in 6 (1.45%) of 413 surgeries. All 6 patients were women with a mean age of 81 years. Four patients had dense nuclear cataracts. In each case, the anterior chamber depth and IOP normalized immediately after pars plana needle aspiration and the procedure concluded uneventfully. Mild vitreous hemorrhage was observed in 1 patient postoperatively. At 1 month, the IOP was normal in 5 of 6 cases, while the CDVA was 20/12 in 5 of 6 cases. Conclusion Although the etiology of AIRES is iatrogenic, immediate resolution was achieved uneventfully with pars plana needle aspiration, which appears to be a safe management technique with satisfactory outcomes. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Comparison of macular morphology between femtosecond laser–assisted and traditional cataract surgery

Comparison of macular morphology between femtosecond laser–assisted and traditional cataract surgery After reading the article by Nagy et al. on femtosecond laser–assisted cataract surgery technology, we have significant methodological concerns about the risk for postoperative cystoid macular edema (CME). These render the conclusions drawn by the authors difficult to support. The incidence of CME following cataract surgery is variable. Differing definitions of CME make it difficult to determine accurately its incidence; a recent review reported the incidence as 0.1% to 2.5%. It is essential to differentiate clinical CME, in which visual impairment is present, from angiographic or subclinical macular edema, in which visual acuity is not impaired. Flach identified 20 factors that could affect the reported incidence of postoperative CME. These factors relate to the patient (underlying vascular diseases such as diabetes mellitus, hypertension, and chronic kidney disease), research methodology, and surgical technique. The numerous shortcomings we find in the Nagy et al. study methodology are as follows. 1. Relevance of subclinical macular edema. The authors state that the incidence of subclinical macular edema after uneventful cataract surgery has become an issue of safety. This is in fact not the case. Subclinical macular edema is defined and diagnosed using fundus fluorescein angiography. It is considered a precursor process that might predispose to CME. The major objective outcome parameter after cataract surgery remains corrected distance visual acuity (CDVA). While macular edema is a critical determinant of surgical success, it is only so when it is clinically significant and results in an adverse effect on CDVA. The authors suggest that the mean CDVA was similar in the traditional phacoemulsification group and the femtosecond laser–assisted cataract surgery group, but no statistical analysis was performed. 2. Methodological bias. Specific patient factors such as age, sex, and refractive error were accounted for, but systemic illnesses (cited above) known to affect the risk for CME were not documented. Despite the study being documented as a prospective case-control series, the criteria for allocation to the traditional phacoemulsification cohort versus the femtosecond laser–assisted cataract surgery cohort were not addressed. There was no record of masking the observers during follow-up and optical coherence tomography (OCT). The mean follow-up was stated to be similar in the 2 cohorts, but there was no statistical

Persistent concerns regarding intracameral cefuroxime

Ophthalmic surgeons should be grateful to Moisseiev and Levinger for illuminating the serious issue of anaphylaxis secondary to the administration of intracameral cefuroxime. A large body of literature supports the incorporation of intracameral cefuroxime toward the conclusion of phacoemulsification cataract surgery, typified by the 2006 European Society of Cataract and Refractive Surgeons report. However, surprisingly or otherwise, there has not been worldwide unanimous adoption of this practice. This correspondence presents an opportunity to highlight some of the persisting concerns surrounding the use of intracameral cefuroxime. Cefuroxime is a second-generation cephalosporin that exerts its bactericidal effect by acting on penicillin-binding protein, thereby disrupting bacterial cell wall synthesis. It could therefore be expected to be useful in preventing many cases of endophthalmitis. The lack of a commercially available preparation of intracameral cefuroxime had led to concerns about contamination and dilution errors. These concerns have been addressed, in part, through the introduction of a purpose-specific preparation (Aprokam), eliminating the 2-step dilution process previously required. However, concerns about the antibacterial characteristics of cefuroxime remain. Although classified as a broad-spectrum antibacterial agent, cefuroxime offers poor coverage against gram-negative organisms such as Pseudomonas spp., which are regularly isolated in endophthalmitis. Furthermore, there exist major gaps in its bactericidal activity against gram-positive organisms including methicillin-resistant Staphylococci, penicillin-resistant S Pneumoniae, and multiresistant Enterococci. There are also pharmacokinetic considerations in evaluating the efficacy of intracameral cefuroxime. With rapid physiological turnover of aqueous humor in the anterior chamber, cefuroxime concentrations reach subtherapeutic levels rapidly. It has been suggested that intracameral cefuroxime concentrations decrease fourfold within an hour of administration. Ocular toxicity of intracameral antibiotics has been established in small studies, exemplified by the toxic anterior segment syndrome. Elevated oxidative stress

Endophthalmitis in Europe: data collection conundrum.

Endophthalmitis in Europe: Data collection conundrum Behndig et al. have summarized available data pertaining to the use of intracameral cefuroxime in Europe for prophylaxis against endophthalmitis following cataract surgery. The readership was alerted to the significant differences in data collectionmethods between its component countries. Data from mandatory National Registries were available from only Sweden and the Netherlands. No information on endophthalmitis rates was available from Belgium and Italy. Therefore, figures were extrapolated from the European Registry of Quality Outcomes for Cataract and Refractive Surgery database and the European Society of Cataract and Refractive Surgeons trial, respectively. Data were collected from France, United Kingdom, Germany, Spain, and Poland by way of nonmandatory registries or surveys. The significant differences in data collection allow limited conclusions to be drawn about the true rate of endophthalmitis within each country. This therefore eliminates the ability to compare endophthalmitis rates between European countries. There are widely varying reported rates of endophthalmitis. These variations were apparent in the data reported by Behndig et al., in which rates ranged from less than 0.04% in Sweden to 0.50% in Spain. Considerable disparity in published rates of endophthalmitis also exists within single countries; eg, 0.03% to 0.20% in the United Kingdom. These variations are evident in other studies from around the world regarding purported rates of endophthalmitis. The systematic review by Taban et al. suggests that in 2000 to 2003, the worldwide incidence of endophthalmitis was 0.265%. Correspondence published by our group in 2009 reviewed all public hospital admissions for endophthalmitis in the most populous state in Australia, New South Wales. It revealed the alarmingly high endophthalmitis incidence of 0.834% between July 1994 and June 2003. These large discrepancies in endophthalmitis rates may be accounted for by the differing methods of data collection. Data obtained in a nonmandatory fashion will probably underestimate true rates of endophthalmitis. We concur with the statement by Behndig et al. that “the [given] overview does not pretend to report actual practice patterns and epidemiological facts.” For this reason and others mentioned, we recommend a cautious interpretation of the figures. Furthermore, the role of intracameral cefuroxime in the prophylaxis of endophthalmitis remains uncertain. There are other confounders to consider, including variations in patient factors, perioperative

Iris floculli: elevated intraocular pressure or threat to life?

reports and the fact that the size and surface anatomy of the plica as well as the nasal edge of the plica semilunaris (i.e. the border between the plica semilunaris and the caruncle) display considerable variations, which could potentially affect the accuracy of measurements. Accordingly, findings will have to be confirmed by prospective studies that would include patients with pterygium at an early stage of growth and would allow sufficient follow-up time to evaluate a potential association between pterygium growth rate and the size of the plica semilunaris.

Retreatment strategies following Small Incision Lenticule Extraction (SMILE): In vivo tissue responses

With any refractive correction, including Small Incision Lenticule Extraction (SMILE), there may be a residual refractive error that requires a retreatment. Here, we investigated the tissue responses following various retreatment procedures in a rabbit model of SMILE. All rabbits underwent a -6.00D correction with SMILE. Two weeks later, they underwent -1.00D enhancement by: (i) VisuMax Circle, followed by excimer ablation (S+C); (ii) secondary SMILE anterior to the primary procedure (S+SE); or (iii) surface ablation (S+P), and were examined for 28 days. S+P induced corneal edema and haze, and more CD11b- (23±6 cells) and TUNEL-positive (36±4 cells) cells in the central stromal superficial layers early post-operatively (p<0.001 compared to other procedures). The corneas appeared normal on day 28 after S+P, but had a lower number of keratocytes near the laser ablated plane compared to other procedures. S+SE and S+C did not induce corneal haze and resulted similar level of fibronectin. However, S+C resulted in more inflammatory (10±2 cells; p = 0.001) and apoptotic cells (25±2 cells; p<0.001) compared to S+SE (7±1 inflammatory cells and 21±3 apoptotic cells) early post-operatively. In conclusion, each SMILE retreatment method resulted in unique tissue responses. S+SE offers advantages, such as minimal inflammation and cell death, as well as maintaining a ‘flap-less’ surgery, over other procedures. However, depending on the degree of enhancement, the lenticule may become too thin to be extracted and the procedure becomes more difficult to perform than S+C and S+P. S+P can maintain corneal integrity by avoiding flap creation and is technically more simple to perform than the others, but the surgery needs to be supplemented with mitomycin-C in order to reduce inflammation and modulate better wound healing.

Preseptal epidermal eyelid abscess related to unreported trauma in a patient with schizoaffective disorder.

9 months after nephrectomy (Fig. 3). First described by Victor Alexander Bochdalek in 1867, a Bochdalek hernia is a congenital hernia created by improper fusion of the posterolateral foramina of the diaphragm. These are the most common type of congenital diaphragmatic hernias. Over 95% of cases are diagnosed in the neonatal period due to associated pulmonary insufficiency. There are only 173 cases of symptomatic Bochdalek hernias reported in the adult population in worldwide literature. The mean age of presentation is 40 years old, but there is a wide age range, from 15 to 88 years. Adult presentations of Bochdalek hernias are often insidious and intermittent, with mainly vague gastrointestinal symptoms (abdominal pain, nausea, vomiting, constipation) or respiratory symptoms (chest pain, dyspnoea, wheezing). Others present with serious complications of incarceration or strangulation, necessitating emergency surgery. A precipitating factor was noted in only 25% of reported cases. Common precipitating factors were pregnancy and exertion, but also included trauma, large meals, retching and coughing. Surgical repair has been performed via five different approaches: laparotomy, thoracotomy, laparoscopy, thoracoscopy or a combination of these. For emergent cases, laparotomy was the most common approach; however, laparoscopic and thoracoscopic repairs have been performed successfully in the last two decades on an elective basis. More recent CT and autopsy studies have revealed that the incidence of asymptomatic Bochdalek hernia in adulthood is higher than previously thought, with an estimated range between 0.17% and 12.7%. Asymptomatic hernias are often associated with liver, gallbladder, kidney and/or omentum, and occur more commonly on the right side and in women. To our knowledge, this is the first case describing a previously asymptomatic congenital hernia unveiled after nephrectomy. Misdiagnosis of diaphragmatic hernias is common, regardless of aetiology, due to the wide variation in symptoms and the rarity of the defect. In the literature, only 65% of Bochdalek hernia cases were diagnosed preoperatively. Although uncommon in adults, these abnormalities should be known and managed appropriately to avoid potential dire consequences, and associated morbidity and mortality.