Zonular dialysis and cataract surgery: results from a UK tertiary eye care referral centre

OBJECTIVE

Zonular dialysis (ZD), referred to as the presence of a deficient zonular support for the lenticular capsule, might be the result of several causes and be detected only at the time of cataract surgery. The aim of this study was to evaluate pre-, intra-, and postoperative features of eyes with ZD regardless of the etiology detected during cataract surgery.

METHODS

A single-centre retrospective observational cohort study was performed at Moorfields Eye Hospital (NHS Foundation Trust, London, U.K.) to identify patients who underwent cataract surgery whose procedure was intraoperatively described as being complicated by ZD between January 1, 2014, and August 22, 2019. Patient characteristics, intraoperative clinical findings, visual and refractive outcomes, and postoperative complications were recorded.

RESULTS

ZD was identified intraoperatively in 447 eyes. In most cases (213 of 223; 96.8%), patients underwent a phacoemulsification procedure, not requiring any conversion to intracapsular or extracapsular extraction technique. Intraoperative complications increased to 46.2% (103 of 223), with no significant correlation with ZD width. Capsular tension rings (CTRs) were implanted in 43.4% of patients (97 of 223). The use of CTRs correlated with better postoperative visual and refractive outcomes.

CONCLUSIONS

ZD is a serious complication of cataract surgery requiring prompt intraoperative diagnosis and proper management. While it tends to worsen cataract surgery outcomes, the implantation of CTRs during the surgical procedure seems to be associated with better postoperative visual and refractive results.

Immediate sequential vs delayed sequential bilateral cataract surgery: systematic review and meta-analysis

The main aim of this systematic review and meta-analysis was to evaluate the safety and efficacy profile of immediate sequential bilateral cataract surgery (ISBCS) compared with delayed sequential bilateral cataract surgery (DSBCS). MEDLINE Ovid, EMBASE, and CENTRAL databases were searched. Outcome measures were postoperative visual acuity, postoperative spherical equivalent (refractive outcome), endophthalmitis, corneal edema, pseudophakic macular edema, and posterior capsule rupture (PCR). 13 articles met criteria for final inclusion. A total of 11 068 622 participants (18 802 043 eyes) were included. No statistically significant differences between ISBCS and DSBCS were identified in all the postoperative outcomes evaluated. However, a higher risk for PCR was identified in the ISBCS group from the pooled analysis of nonrandomized studies (risk ratio, 1.34, 95% CI, 1.08-1.67, P = .0081). In our view, the ISBCS approach has an acceptable safety-efficacy profile, comparable with DSBCS. Future investigations are warranted, with a focus on the analysis of risk factors for surgical complications, patient-reported outcome-measures, and cost effectiveness.

Incidence and complications of retained lens fragment in the anterior chamber after uneventful cataract surgery in a United Kingdom tertiary center

PURPOSE

To analyze the outcomes of retained lens fragment (RLF) in the anterior chamber after uneventful cataract surgery.

SETTING

Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom.

DESIGN

Retrospective, observational cross-sectional study.

METHODS

A single-center, retrospective review was performed to identify patients who underwent RLF removal after uneventful phacoemulsification surgery between October 2012 and November 2018; 122 eyes from 121 patients were identified. Patient characteristics, clinical findings, visual outcomes, and need for subsequent surgical procedure were recorded. Main outcomes were change in corrected distance visual acuity (CDVA), and number and risk factors associated with additional surgery following RLF removal.

RESULTS

One hundred twenty-two RLF over a total of 98 467 uneventful phacoemulsification surgeries were identified, with an incidence of 1 (0.124%) in 807 operations. The mean CDVA improved significantly after RLF removal from 0.32 to 0.26 logMAR (SD 0.26) (P = .001). Six eyes (4.9%) had persistent corneal edema that required endothelial keratoplasty (EK) after a mean of 13 months after RLF removal (SD 12 months; median 8; range 4 to 35). Risk factors for EK include α-receptor blocker use (odds ratio [OR], 6.75; 95% CI, 1.069, 42.63), increased interval (month) between cataract surgery and diagnosis of RLF (OR, 1.29; CI: 1.080, 1.541), increased interval between cataract surgery and RLF washout (OR, 1.28; CI, 1.075, 1.522), and RLF diagnosis on gonioscopy (OR, 10.60; CI, 1.885, 59.59).

CONCLUSIONS

RLF is a rare complication of uneventful cataract surgery and appears more frequently in challenging cataract cases and myopic eyes. CDVA improved significantly after RLF removal, but approximately 1 in 20 eyes needed additional surgery-mainly EK for corneal decompensation.

Controlled Periodic Illumination Enhances Hydrogen Production by over 50% on Pt/TiO2

Efficient solar water photosplitting is plagued by large overpotentials of the HER and OER. Even with a noble metal catalyst, the hydrogen evolution reaction can be limited by the strong M-H bonding over some metals, such as Pt, Pd, and Rh, inhibiting hydrogen desorption. H absorption is regulated by the potential at the metal nanoparticles. Through controlled periodic illumination of a Pt/TiO2 suspension, we hypothesized a fast variation of the photopotential that induced catalytic surface resonance on the metal, resulting in more than a 50% increase of the efficiency at frequencies higher than 80 Hz.

Descemet membrane endothelial keratoplasty in vitrectomized eyes: a case series of outcomes and complications

BACKGROUND

The aim of this study was to evaluate the clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) in vitrectomized eyes.

METHODS

A multi-surgeon, retrospective case series of previously vitrectomized eyes that underwent DMEK between 2013 and 2018 at Moorfields Eye Hospital. Patients' demographics, preoperative, intraoperative and postoperative data were collected.

RESULTS

In total, 14 eyes of 13 patients, aged 63 ± 14.6 years were included. Three eyes had intraoperative posterior dislocation of the DMEK graft into the vitreous cavity, two of these were aphakic and one had an unstable PCIOL. Postoperatively, one graft had a total detachment and required repeat keratoplasty for primary failure, two grafts had visually significant partial detachment and needed rebubbling. Three patients developed high intraocular pressure (IOP) and one required an urgent glaucoma drainage device 1-month post-DMEK. The mean corrected distance visual acuity was 0.81 ± 0.42 logMAR preoperatively, and postoperatively was 0.6 ± 0.51 at 3 months (p = 0.414); 0.69 ± 0.81 at 6 months (p = 0.684); and 0.7 ± 0.8 at 12 months (p = 0.658).

CONCLUSIONS

DMEK in vitrectomized eyes has unique challenges that necessitate careful preoperative planning. We observed a significant proportion of dislocated grafts in vitrectomized eyes with either unstable IOL or aphakic. Moreover, vitrectomized eyes with secondary glaucoma may be particularly vulnerable to uncontrolled IOP postoperatively and close monitoring is essential to prevent worsening of visual acuity. We recommend that DMEK may not be a feasible option in eyes that are prone to collapse, in particular aphakic vitrectomized eyes, as opposed to DSAEK or penetrating keratoplasty.

Diagnostic Salivary Tests for SARS-CoV-2

The diagnosis of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection relies on the detection of viral RNA by real-time reverse transcription polymerase chain reaction (rRT-PCR) performed with respiratory specimens, especially nasopharyngeal swabs. However, this procedure requires specialized medical personnel, centralized laboratory facilities, and time to provide results (from several hours up to 1 d). In addition, there is a non-negligible risk of viral transmission for the operator who performs the procedure. For these reasons, several studies have suggested the use of other body fluids, including saliva, for the detection of SARS-CoV-2. The use of saliva as a diagnostic specimen has numerous advantages: it is easily self-collected by the patient with almost no discomfort, it does not require specialized health care personnel for its management, and it reduces the risks for the operator. In the past few months, several scientific papers, media, and companies have announced the development of new salivary tests to detect SARS-CoV-2 infection. Posterior oropharyngeal saliva should be distinguished from oral saliva, since the former is a part of respiratory secretions, while the latter is produced by the salivary glands, which are outside the respiratory tract. Saliva can be analyzed through standard (rRT-PCR) or rapid molecular biology tests (direct rRT-PCR without extraction), although, in a hospital setting, these procedures may be performed only in addition to nasopharyngeal swabs to minimize the incidence of false-negative results. Conversely, the promising role of saliva in the diagnosis of SARS-CoV-2 infection is highlighted by the emergence of point-of-care technologies and, most important, point-of-need devices. Indeed, these devices can be directly used in workplaces, airports, schools, cinemas, and shopping centers. An example is the recently described Rapid Salivary Test, an antigen test based on the lateral flow assay, which detects the presence of the virus by identifying the spike protein in the saliva within a few minutes.

Cataract surgery in eyes with congenital ocular coloboma

PURPOSE

To assess the safety, efficacy, and complication rate of phacoemulsification and intraocular lens (IOL) implantation in patients with congenital uveal coloboma and to evaluate the role of pupilloplasty.

METHODS

A retrospective review of 41 eyes (31 patients) with congenital coloboma that underwent phacoemulsification and IOL implantation between September 2012 and September 2018. Preoperative, intraoperative, and postoperative data were collected for analysis.

RESULTS

The mean patient age at surgery was 53.9 years (range 15-82). The primary indication for surgery was cataract removal for visual improvement, and lens subluxation was additionally present in two eyes (5%) preoperatively. The mean preoperative corrected distance visual acuity (CDVA) was 0.90 LogMAR. Phacoemulsification surgery was performed in all cases and nine eyes (22%) had pupilloplasty for pupil reconstitution at the time of the procedure. Surgeon grade varied from trainee surgeon under supervision to consultant. Eight patients (19.5%) had posterior capsular rupture (PCR) with or without vitreous loss requiring anterior vitrectomy. Of these, 2 cases (5%) had dropped nuclear fragments requiring subsequent pars plana vitrectomy and lens fragment removal. The mean postoperative CDVA was 0.62 LogMAR (p = 0.0003).

CONCLUSION

Patients with iridolenticular choroidal coloboma appear to be more at risk of complications, as were cases performed by non-consultant surgeons. Contrary, patients with phakodonesis, preoperative anterior chamber vitreous, dense cataracts, and cases were iris hooks used had no significant difference at PCR rate. The risk of postoperative glare and pupilloplasty needs to be considered in cases with good visual potential to avoid a possible second procedure.

Primordial odontogenic tumour: A systematic review of the common but also unusual features of this novel entity

BACKGROUND

Primordial odontogenic tumour (POT) is a novel entity that was described in 2014 and that is included in the group of benign mixed epithelial and mesenchymal odontogenic tumours. In recent years, several papers have added new cases with some clinical and histopathological aspects that slightly differ from those described in the original report. The aim of this systematic review is to update all available data on POT published in the literature and to identify those features of the neoplasm that require further investigation.

MATERIALS AND METHODS

A systematic review of literature was conducted using PubMed, Embase, Web of Science and Scopus. Additional sources were also checked. Publications reporting cases with enough clinicopathological information were included, without any time or language restrictions. Histopathological or radiological studies were considered for qualitative analysis.

RESULTS

A total of 30 publications were included. Seventeen papers were used for quantitative analysis while 13 papers were used only for qualitative analysis. A total of 18 cases of POT were identified. Some clinical, radiographic, histopathological and therapeutic features were common in all reported cases, while other aspects of the neoplasm were inconsistent through published cases. This inconsistency was particularly remarkable when dealing with the histopathological features of the neoplasm.

DISCUSSION

Some issues about POT remain unclear and deserve to be clarified by future reports. The description of the odontogenic epithelium covering the ectomesenchyme is often contradictory, while it remains debatable whether peripheral ameloblastic epithelial islands or hard dental tissue deposition can occasionally occur within the tumour.

Comparing capsular bag performance of a hydrophilic and a hydrophobic intraocular lens: A randomised two-centre study

Purpose:

To evaluate the capsular bag performance and posterior capsule opacification development of two intraocular lenses differing in material and design.

Methods:

This study included patients who were scheduled for cataract surgery and compared a hydrophilic intraocular lens (Super flex® intraocular lens; Rayner Surgical, Worthing, UK) with a hydrophobic intraocular lens (AcrySof® SA60AT; Alcon, Fort Worth, TX, USA). Follow-ups were performed 1 month and 2 years after cataract surgery, including a slit lamp examination and retroillumination images.

Results:

In total, 80 eyes of 80 patients were recruited. At the 1-month follow-up, 6 of 39 cases had a gap between the posterior lens capsule and intraocular lens (1 case in the hydrophilic intraocular lens group and 5 cases in the hydrophobic intraocular lens group; p = 0.348). Objective and subjective posterior capsule opacification scoring showed no statistically significant difference between both groups (p = 0.123).

Conclusion:

Both intraocular lens showed a good capsular bag performance and a relatively low posterior capsule opacification development within the first 2 years after surgery.

Surgical efficiency in femtosecond laser cataract surgery compared with phacoemulsification cataract surgery: a case-control study

OBJECTIVES

To investigate differences in surgical time, the distance the surgical instrument travelled and number of movements required to complete manual phacoemulsification cataract surgery versus femtosecond laser cataract surgery.

DESIGN

Non-randomised comparative case series.

SETTING

Single surgery site, Moorfields Eye Hospital, UK.

PARTICIPANTS

40 cataract surgeries of 40 patients.

INTERVENTIONS

Laser-assisted and manual phacoemulsification cataract surgery. Laser-assisted surgery cases were performed using the AMO Catalys platform.

PRIMARY AND SECONDARY OUTCOME MEASURES

Computer vision tracking software PhacoTracking were applied to the recordings to establish the distance the instrument travelled, total number of movements (the number of times an instrument stops and starts moving) and time taken for surgery steps including phacoemulsification, irrigation-aspiration (IA) and overall surgery time. The time taken for laser docking and delivery was not included in the analyses.

RESULTS

Data on 19 laser-assisted and 19 manual phacoemulsification surgeries were analysed (two cases were excluded due to insufficient video-recording quality). There were no differences in the number of instrument moves, the distance the instrument travelled or time taken to complete the phacoemulsification stage. However for IA, the number of instrument moves (manual: mean 20 (SD 15) vs laser: mean 38 (SD 22), P=0.008) and time taken (manual: mean 75 s (SD 24) vs laser: mean 108 s (SD 36), P=0.003) were significantly greater for laser cases. For laser versus manual cases overall, there was no difference in number of moves or the distance the instrument travelled, but laser cases took longer (mean 88 s, P=0.049).

CONCLUSIONS

Laser cataract surgery cases took longer to complete without accounting for the time taken to complete the laser procedure itself. This appears to be in part due to IA requiring more instrument manoeuvres and taking longer to complete. Data from a large randomised series would better elucidate this relationship.

Vertical implantable collamer lens (ICL) rotation for the management of high vault due to lens oversizing

PURPOSE

To describe the good outcome of implantable collamer lens (ICL) rotation to reduce post-operative vault.

METHODS

Retrospective analysis of case report. A 43-year-old woman had V4c EVO + myopic non-toric ICL implantation and post-operatively she presented with anisocoria and high vault. She underwent surgery to rotate the ICL 90 degrees to a vertical orientation.

RESULTS

We achieved a reduction in the vault from 1020 to 486 μm after vertical ICL rotation. Satisfactory refractive outcome and optimal vault were achieved and maintained during the period of follow-up.

CONCLUSION

Optimal ICL sizing is important as too high vault/clearance is associated with problems such as angle closure glaucoma, pupil dilatation and anisocoria and too low vault/clearance to increased risk of cataract formation. Non-toric ICL rotation can be a simple surgical technique to deal with oversized lenses thus avoiding ICL exchange.

Cataract Surgery in Patients with Keratoconus: Pearls and Pitfalls

Background:

Keratoconus (KC) is a common ectatic disorder resulting in progressive corneal thinning and irregular astigmatism. It has been observed that patients affected by KC are more likely to develop lens opacities earlier compared to non-keratoconic patients.

Objective:

Intraocular lens (IOL) selection and refractive outcome prediction are among a number of factors that can make cataract surgery in keratoconic patients challenging. Accurate biometry is often difficult to obtain due to unreliable K measurements and lack of dedicated biometric formulae. The use of toric IOLs has also been investigated.

Conclusions:

Determining the stage of KC, pre-operative patient counselling and the preferred method of refractive correction are all crucial to obtain successful postoperative outcomes and good patient satisfaction. The use of toric IOLs can achieve good results only in selected low-grade keratoconic eyes.

ADULT syndrome: dental features of a very rare condition

The Acro-Dermato-Ungual-Lacrimal-Tooth syndrome (ADULT syndrome) is one of the rarest ectodermal dysplasias and it is associated with several malformations involving especially the limbs. The most clinical features are the presence of ectrodactyly, syndactyly, hypermelanosis or multiple lentigines, onhycodysplasia, abnormalities in the lacrimal duct, recurrent conjuntivitis, photophobia, mammarian hypoplasia, hypotrichosis and frontal alopecia, hypohydrosis, cutaneous photosensitivity, nasal bridge prominence, exfoliative dermatitis and xerosis. The ectodermal dysfunction expresses itself with conoid teeth, enamel hypoplasia, dentinal dysplasia and especially hypodontia, with following functional and aesthetic defects. We report the case of an 11-year-old Caucasian girl affected by ADULT syndrome.

The “elfin face”: craniofacial and dental aspects of the Williams-Beuren syndrome

Williams Syndrome is a rare congenital disorder characterized by supravalvular aortic stenosis, peripheral pulmonary artery stenosis, mental retard and dysmorfic facial features. As regards the dental aspects of the syndrome, the deletion of the elastin gene induced clinicians to suspect periodontal alterations with a greater frequency of gingivo-periodontitis, but on the contrary no association between the syndrome and periodontal diseases have been found. Furthermore, patients show a higher frequency of teeth hypoplasia, an abnormal tooth morphology during primary dentition (12.5%) and during permanent dentition. We present a case report of a 12-year-old Caucasian boy affected by Williams-Beuren Syndrome who visited our hospital for a dental and orthodontic evaluation.

Oral manifestations of selective IgA-deficiency: review and case-report

Immunoglobulin A deficiency is the most common primary immunodeficiency defined as decreased serum level of IgA (less than 7 mg/dl) in the presence of normal levels of other immunoglobulin isotypes. Most individuals with IgA deficiency are asymptomatic and identified coincidentally. However, some patients may present with recurrent infections, allergic disorders and autoimmune manifestations, such as diabetes mellitus, Graves disease and celiac disease. The international literature has not produced any kind of review yet about intra-oral manifestations of selective IgA-deficiency. L.S., a 7-year-old Caucasian girl, was examined at our hospital. After she had undergone a professional dental cleaning, a symmetric, bilateral ulcerative gingivitis developed nearby the upper second primary molars. The gingival ulcers were persistent and did not disappear in the following 3 weeks. In the meantime, the young patient reported the presence of gastrointestinal symptoms. IgA serum level was 4.5 mg/dl, while the other isotypes levels were in the common range. The diagnosis of selective IgA-deficiency was formulated and the girl underwent further examination for the specific IgG autoantibodies in celiac disease, which were not present. Consequently, a full prevention program was planned. This case report emphasizes the role of the paediatric dentist in the early detection of systemic disorder, such as the immunological diseases. The oral cavity often reveals to be the first site of manifestation of important systemic diseases. Immunoglobulin A (IgA) deficiency is the most common primary immunodeficiency and is defined as a decrease in serum IgA levels in the presence of normal levels of other immunoglobulin isotypes (1). Serum IgA deficiency was first described in children with ataxia-telangiectasia (2) and has since been identified in other patients, including normal patients. The prevalence of IgA deficiency ranges from 1:223 to 1:1000 in community studies and from 1:400 to 1:3000 in healthy blood donors (3).

Initial experience using a femtosecond laser cataract surgery system at a UK National Health Service cataract surgery day care centre

OBJECTIVES

To describe the initial outcomes following installation of a cataract surgery laser system.

SETTING

National Health Service cataract surgery day care unit in North London, UK.

PARTICIPANTS

158 eyes of 150 patients undergoing laser-assisted cataract surgery.

INTERVENTIONS

Laser cataract surgery using the AMO Catalys femtosecond laser platform.

PRIMARY OUTCOME MEASURE

intraoperative complications including anterior and posterior capsule tears.

SECONDARY OUTCOME MEASURES

docking to the laser platform, successful treatment delivery, postoperative visual acuities.

RESULTS

Mean case age was 67.7±10.8 years (range 29-88 years). Docking was successful in 94% (148/158 cases), and in 4% (6/148 cases) of these, the laser delivery was aborted part way during delivery due to patient movement. A total of 32 surgeons, of grades from junior trainee to consultant, performed the surgeries. Median case number per surgeon was 3 (range from 1-20). The anterior capsulotomy was complete in 99.3% of cases, there were no anterior capsule tears (0%). There were 3 cases with posterior capsule rupture requiring anterior vitrectomy, and 1 with zonular dialysis requiring anterior vitrectomy (4/148 eyes, 2.7%). These 4 cases were performed by trainee surgeons, and were either their first laser cataract surgery (2 surgeons) or their first and second laser cataract surgeries (1 surgeon).

CONCLUSIONS

Despite the learning curve, docking and laser delivery were successfully performed in almost all cases, and surgical complication rates and visual outcomes were similar to those expected based on national data. Complications were predominately confined to trainee surgeons, and with the exception of intraoperative pupil constriction appeared unrelated to the laser-performed steps.

Outcomes of femtosecond laser-assisted mushroom-configuration keratoplasty in advanced keratoconus

PURPOSE

To evaluate the long-term outcomes after femtosecond laser (FSL)-assisted mushroom-configuration keratoplasty in advanced keratoconus.

PATIENTS AND METHODS

Thirteen eyes with Amsler-Krumeich stage IV keratoconus underwent FSL-assisted mushroom-configuration penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK) at a tertiary referral centre. Preoperative risk factors included low orneal thickness, high keratometry measurements, previous hydrops, and central stromal scarring. Main outcome measures were visual acuity and refractive outcome.

RESULTS

The median follow-up was 33 months (range: 4-43). Preoperatively, the mean corrected distance visual acuity (CDVA) was 1.22±0.47 LogMAR (range: 0.5-1.9 LogMAR), mean minimum corneal thickness was 282±100.8 μm (range: 147-478 μm), and mean average keratometric (K) value was 63.4±7.63 dioptre (D; range: 57.0-75.7 D). Four patients underwent PKP and nine underwent DALK (two converted to PKP). Five patients subsequently underwent a modified arcuate mushroom interface dissection (AMID) procedure for astigmatic correction. At the final follow-up, the mean CDVA was 0.05±0.13 LogMAR (range: -0.10 to 0.20 LogMAR), mean spherical equivalent was -3.21±3.21D, mean cylindrical refractive error was 3.23±2.20 D, and mean average K was 43.1±1.53 D. Complications included early graft dehiscence, corneal vascularisation, stromal rejection, and sclerokeratitis. Sutures were completely removed at the mean 18.4 months for PKP and 9.1 months for DALK postoperatively.

CONCLUSION

FSL-assisted mushroom-configuration keratoplasty is feasible and safe in patients with stage IV keratoconus. AMID could further enhance the refractive outcome safely.

Thin Film Nanocrystalline TiO2 Electrodes: Dependence of Flat Band Potential on pH and Anion Adsorption

Thin nanocrystalline TiO2 films were produced on ITO conductive glass by dip-coating of a sol-gel TiO2 precursor. The transparent films were characterized from the optical and structural point of view with UV-Vis, Spectroscopic Ellipsometry, Raman and X-ray photoelectron spectroscopies, the roughness of the coating by AFM. The changes in the electrochemical properties features of ITO/TiO2 electrodes were evaluated in the presence of different electrolytes (KCI, Na2SO4 and phosphate buffer) with the aim to clarify the role of the ion adsorption on the structure of the electrical double layer. Electrochemical tests (Cyclic Voltammetry, CV, and Impedance Electrochemical Spectroscopy, EIS) showed a strong influence of the electrolyte properties on the semiconductor band edge position in the electrochemical scale and on band bending. The CV profiles recorded can be explained by considering that the interface capacity is due to the charging of surface states (e.g., Ti(IV) surface sites coordinated by oxygen atoms, ≡Ti-OH or Ti-O-Ti). The surface charge is strongly affected also by the density and nature of adsorbed ions and by dissociation of surficial OH. Of interest the fact that for the produced nanocrystalline electrodes the flat band potential, measured from the Mott-Schottky analysis of the space charge layer capacity obtained with EIS, showed a non Nernstian behavior with the pH probably caused by a change in the surface acidity as a consequence of specific anion adsorption. The modulation of flat band potential with adsorbed ions is of interest for many applications, in particular for photocatalysis (change in the redox potential of photogenerated carriers) and for photovoltaic applications like DSSC (change in the photopotentials).

Complications and outcomes of phacoemulsification cataract surgery complicated by anterior capsule tear

PURPOSE

To study the results of phacoemulsification cataract surgery complicated by anterior capsule tear.

DESIGN

Retrospective interventional controlled case series.

METHODS

Consecutive series of eyes suffering intraoperative anterior capsule tear and others with uneventful cataract surgery at Moorfields Eye Hospital were investigated. Biometric, intraoperative, and postoperative details were recorded. The exclusion criteria were combined surgical procedures, planned manual extracapsular cataract extraction, and history of previous intraocular surgery or eye trauma. The main outcome measures were intraoperative capsule complication rates, refractive and visual outcomes, and incidence of short-term postoperative complications. Two-sided Fisher exact and paired t tests were used for categorical and continuous data, respectively.

RESULTS

The study and control groups included 239 and 212 eyes, respectively. In the study group, planned phacoemulsification was converted to manual extraction in 5 cases (2%); a concurrent posterior capsule rupture occurred in 58 eyes (24%) with a rate of nuclear lens material drop in the posterior segment of 5% (11 cases). Over 11% of eyes (n = 27) underwent unplanned secondary surgical procedures. Overall, the refractive outcomes were poor in 22.4% of eyes (postoperative refraction ≥1 diopter of target), and were statistically worse (P < .0001). A significant visual improvement was observed in the majority of the study group eyes (71%); permanent visual loss occurred in 4 eyes (1.7%).

CONCLUSIONS

Anterior capsule tear can lead to additional intraoperative complications, with a relatively high incidence of secondary interventions. Overall, permanent visual loss can be observed and worse refractive outcomes are to be expected, particularly if the lens is being implanted out of the bag.

Accuracy of the refractive prediction determined by multiple currently available intraocular lens power calculation formulas in small eyes

PURPOSE

To observe the refractive outcomes of cataract surgery in small adult eyes, and to investigate the accuracy of different intraocular lens (IOL) power prediction formulas.

DESIGN

Retrospective interventional case series.

METHODS

We included consecutive small eyes undergoing uneventful phacoemulsification cataract surgery with a single highly powerful IOL (Acrysof SA60AT) implanted in the capsular bag (range of powers +35.0 to +40.0 diopters [D]), at the Cataract Centre for Moorfields Eye Hospital. Exclusion criteria were combined or previous intraocular surgical procedures, and any type of intraoperative complications. Main outcome measures were mean prediction errors with Hoffer Q, Holladay 1, Holladay 2, Haigis, SRK-T, and SRK-II IOL power prediction formulas and proportions of eyes achieving absolute errors within the dioptric ranges of 0.5, 1.0, and 2.0 D of target and emmetropia, respectively. The ANOVA test was used to compare the refractive results among various formulas.

RESULTS

Twenty-eight eyes were studied; the mean numerical error was 0.22 ± 1.22 D and the mean absolute error was 0.95 ± 0.78 D with the adopted Hoffer Q formula; 39%, 61%, and 89% of the eyes had a final refraction within 0.5 D, 1.0 D, and 2.0 D of target, respectively. None of the latest-generation formulas significantly outperformed the others (P = .245).

CONCLUSIONS

The Hoffer Q formula led to good or fair refractive outcomes in less than two thirds of the cases. With Holladay 1 and 2 and Haigis formulas, outcomes would have not been significantly different. The SRK formulas yielded less accurate predictions. Possible reasons are discussed.

Central toxic keratopathy after laser in situ keratomileusis

PURPOSE

To review cases of central toxic keratopathy (CTK) occurring over a period of 46 days.

SETTING

Moorfields Eye Hospital, London, United Kingdom.

DESIGN

Retrospective consecutive case series.

METHODS

This was a review of patients with CTK after uneventful laser in situ keratomileusis (LASIK) performed by 1 of 5 surgeons at a single institute. The following parameters were analyzed: corrected distance visual acuity (CDVA), manifest refraction, and central corneal thickness from Scheimpflug pachymetry readings (Pentacam).

RESULTS

The cohort consisted of 15 eyes of 9 patients. Thirteen eyes were diagnosed within 7 days after LASIK, while the remaining 2 eyes developed CTK 12 days postoperatively. In 10 eyes, the time to resolution was 1 to 8 months. Five eyes still had residual signs at the last outpatient visit. At the final follow-up, 3 eyes (20%) had a CDVA worse than 0.0 logMAR.

CONCLUSIONS

Although a rare entity, CTK can occur in clusters. Although a cause was not fully isolated, ultimately each eye achieved excellent CDVA (all better than 0.2 logMAR) at the last follow-up.

Cataract surgery in small adult eyes

AIM

To evaluate the clinical outcomes of phacoemulsification cataract surgery in microphthalmos.

METHODS

Retrospective consecutive case series of eyes with axial length <20.9 mm, and requiring a high intraocular lens (IOL) power (≥30 or ≥35 dioptres for anterior or posterior chamber fixation, respectively), with no history of previous ocular surgery, and undergoing planned phacoemulsification cataract surgery with IOL implantation at Moorfields Eye Hospital was investigated to observe the incidence of intraoperative and postoperative complications.

RESULTS

During a 5-year study period, 47 of 22,093 eyes were treated in two locations (0.21%). Thirty-nine eyes met the study inclusion criteria. No serious intraoperative adverse events were recorded. Severe postoperative complications (retinal detachment and chronic postoperative uveitis) occurred in two cases. The postoperative corrected distance visual acuity (CDVA) was logMAR 0.30 or better in 24 eyes (62%), and only three eyes obtained worse vision. The overall ocular comorbitidy rate was 53%; 10 microphthalmic eyes (26%) presented with associated congenital or hereditary pathology, and had worse visual outcomes (p<0.0001).

CONCLUSIONS

Microphthalmic eyes requiring high IOL power are rare, and their presence is often associated with other ocular congenital or acquired disorders. Overall, the clinical outcomes were satisfactory and the surgical procedure affected by a low complication rate.

Moorfields technique of donor cornea mounting for femtosecond-assisted keratoplasty: use of viscoelastic in the artificial anterior chamber

Appropriate mounting and cutting of the donor sclero-corneal cap is often cumbersome during femtosecond laser-assisted keratoplasty. The authors describe a technique for donor cornea femtosecond laser cutting using ophthalmic viscoelastic devices. The donor sclero-corneal cap is mounted on the artificial anterior chamber using a dispersive ophthalmic viscoelastic device instead of saline solution. The chances of artificial anterior chamber pressure loss, inadequate applanation, and fluid leaks are consistently reduced with the use of dispersive ophthalmic viscoelastic devices. The speed of donor femtosecond laser cutting is increased. The viscosity and elasticity of dispersive ophthalmic viscoelastic devices greatly assist the procedure with regard to ease of applanation, corneal endothelium protection, and decreased distortion of the applanated cornea.

Assessment of a new averaging algorithm to increase the sensitivity of axial eye length measurement with optical biometry in eyes with dense cataract

PURPOSE

To assess the capability of new software to decrease the proportion of eyes that have insufficient signal-to-noise ratio (SNR) in optical biometry.

SETTING

Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom.

DESIGN

Evaluation of diagnostic test or technology.

METHODS

In a prospective study, consecutive cataract patients coming for biometry who were unsuccessfully measured with the former software (version 4) of the IOLMaster partial coherence interferometry (PCI) device were reevaluated with the new composite software (version 5). Subsequently, in a retrospective study, consecutive cataract patients were measured with software version 5. For unsuccessful scans, the type and intensity of cataract were assessed at the slitlamp.

RESULTS

Altogether, 2713 eyes (1956 patients) were included in the study. The prospective study comprised 458 eyes (244 patients), 10.6% of which could not be measured successfully with software version 4. With the composite software, 30% of cases were measured successfully, with a higher proportion (42%) in the posterior subcapsular cataract subgroup. In the retrospective study, of 2255 eyes (1712 patients), 4.7% were not measured successfully using the new algorithm because of white cataract (70 eyes), posterior subcapsular cataract (14 eyes), or dense nuclear cataract combined with posterior subcapsular cataract (13 eyes) or for other reasons (8 eyes).

CONCLUSION

The composite software (version 5) enhanced the SNR, allowing valid measurements in eyes in which optical biometry had previously failed, especially in cases of posterior subcapsular cataract.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned. Additional disclosure is found in the footnotes.

Immediate postoperative intraocular pressure measurements after trabeculectomy with releasable sutures

BACKGROUND

To assess the practicality of same-day intraocular pressure (IOP) review following trabeculectomy with releasable sutures. It is a prospective observational case series study.

METHODS

40 eyes of patients undergoing inpatient trabeculectomy for glaucoma optic neuropathy. IOP measurement at 2, 4, 8, 12 and 24 h following trabeculectomy with releasable sutures. Slit-lamp microscopy documenting surgical complications.

RESULTS

Three patients required intervention within the first 24 h and four patients at 24 h because of raised IOP. Investigating pressure outcomes of low (<8 mmHg) and high (>21 mmHg) the sensitivity and specificity of IOP assessments at 2, 4, 8 and 12 h were compared with a 'gold standard' of IOP at 24 h postoperatively. False negative results persist at time periods for low IOP and are absent for high IOP only at 8 h postoperatively. There is a marked change in IOP over the first 24-h period in some patients, both from high to low and from low to high levels.

CONCLUSIONS

Same-day review of trabeculectomy is not a practical proposition as a policy for a unit with present operative techniques. Indeed the finding of transient high pressures during the first 24 h in some cases suggests that in those patients for whom there is concern (mainly those with severe disc cupping at the time of surgery) at least one IOP check during the first 24 h postoperatively may be warranted in addition to the 24-h postoperative check.

Torque and flattening effects of clear corneal temporal and on-axis incisions for phacoemulsification

PURPOSE

To compare the torque and flattening effect induced by temporal or on-axis clear corneal incisions (CCIs) for phacoemulsification.

SETTING

Moorfields Eye Hospital, London, United Kingdom.

METHODS

Randomized controlled clinical trial on 62 eyes with cataract and mild to moderate corneal astigmatism (<2.60 diopters [D]) having phacoemulsification with a temporal CCI (temporal group) or on-axis CCI (on-axis group). Corneal astigmatism was assessed by corneal topography preoperatively and 3 weeks after surgery. The meridian of the incisions was marked on the cornea before local anesthesia was given to avoid anesthesia-related cyclotorsion. The surgically induced astigmatism (SIA) vector, torque, flattening effect, and accuracy of incision placement were analyzed in the 2 groups and compared with a paired t test.

RESULTS

Three weeks after surgery, the on-axis CCI induced slightly more flattening of the meridian of the incision (mean -0.63 +/- 0.57 D [SD]) than the temporal CCI (mean -0.50 +/- 0.44 D); however, the differences were not statistically significant (P = .31). Simple algebraic difference showed a mean increase in astigmatism magnitude of 0.12 +/- 0.52 D in the temporal group and a mean reduction of 0.21 +/- 0.53 D in the on-axis group (P = .02). The mean absolute torque was 0.28 +/- 0.27 D and 0.53 +/- 0.37 D, respectively (P<.005). The absolute angle of error of incision placement (alpha) was greater after on-axis CCIs (mean 25.9 +/- 20.1 degrees) than after temporal CCIs (mean 14.5 +/- 14.3 degrees) (P = .01).

CONCLUSIONS

In eyes with preoperative astigmatism less than 2.60 D, on-axis CCI phacoemulsification induced slightly more flattening along the incision meridian than temporal CCI phacoemulsification, although the differences were not significant. The on-axis CCI was associated with significantly greater absolute torque and angle of error than the temporal CCI. These factors could limit the benefit of placing the incision on axis when the aim is to reduce preoperative astigmatism in phacoemulsification.

Single bubble sonochemistry: decomposition of alkyl bromide and the isomerization reaction of maleic acid

Single bubble cavitation offers an unique opportunity to evaluate the effect of bubble activity in promoting chemical reactions. In this paper we study the isomerization reaction of maleic acid into fumaric acid using an aqueous solution of maleic acid saturated with CH2Br2. The Br* radicals are generated at the bubble surface and a whitish thread forms. For comparison, the same reaction was conducted in a sonochemical bath. A possible scheme of the reactions activated at bubble surface after the decomposition of organic brominated substances is proposed.

Surgically induced astigmatism after phacoemulsification in eyes with mild to moderate corneal astigmatism

PURPOSE

To determine whether there is a difference in surgically induced astigmatism (SIA) and postoperative uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) between 2 types of clear corneal incisions used in phacoemulsification: the temporal and the on-axis (ie, on the steeper corneal meridian) clear corneal incision (CCTI and CCOI, respectively).

SETTING

Moorfields Eye Hospital, London, United Kingdom.

METHODS

In a prospective randomized controlled trial (pilot study), 61 eyes with cataract and mild to moderate corneal astigmatism (<2.58 diopters [D] on corneal topography) having phacoemulsification (single surgeon, 3.2 mm incision) were randomized to receive CCTI or CCOI. Main outcome measures included postoperative BCVA and corneal astigmatism and SIA (calculated using the Holladay vector analysis formula). Measurements were repeated postoperatively at 3 weeks in all eyes, whereas only 46 eyes made it to the final assessment at 8 weeks. Continuous variables between groups were compared by Student t test. The power of the study was calculated.

RESULTS

At the first follow-up, the difference in SIA between the 2 incision types was 0.15 D and it was not statistically significant (0.65 D in CCOI; 0.50 D in CCTI). At the second follow-up, the difference was 0.29 D and it was statistically significant (0.63 D in CCOI; 0.34 D in CCTI; P = .0004). There was no statistically significant difference in the final postoperative visual acuity. The power of the pilot study was 72%.

CONCLUSION

Seven weeks after small-incision phacoemulsification, the CCTI induced less SIA than the CCOI; however, there were no significant differences in the final UCVA and BCVA.

Different photocatalytic fate of amido nitrogen in formamide and urea

In the comparison of formamide and urea photocatalytic degradation, despite their similar structures, the final fate of bound nitrogen under illumination with TiO2 has shown a different behaviour; both the rate and the ratio of NH4+ and NO3- ion evolution seem not to be linked to the initial nitrogen oxidation state, but to the carbon oxidation state.

Fixed dilated pupil (Urrets-Zavalia syndrome) after air/gas injection after deep lamellar keratoplasty for keratoconus

PURPOSE

To describe three cases of fixed dilated pupil and presumed iris ischemia (Urrets-Zavalia syndrome) after anterior chamber air/gas injection after deep lamellar keratoplasty for keratoconus.

METHODS

Interventional case series. Three eyes of three patients with keratoconus underwent deep lamellar keratoplasty and intraoperative or postoperative injection of air/gas in the anterior chamber to appose the host-donor lamellar graft interface.

RESULTS

Urrets-Zavalia syndrome was diagnosed on clinical grounds in three cases and was associated with the Descemet membrane microperforation intraoperatively and introduction of air/gas into the anterior chamber intraoperatively or postoperatively.

CONCLUSION

A fixed dilated pupil is an uncommon complication of penetrating keratoplasty for keratoconus that can also develop after deep lamellar keratoplasty. Leaving an air or gas bubble in the anterior chamber of a phakic eye after deep lamellar keratoplasty is a risk factor and should therefore be avoided.

Phenol photonitration upon UV irradiation of nitrite in aqueous solution II: effects of pH and TiO2

Phenol photonitration and photonitrosation were studied both in homogeneous and in heterogeneous phase in the presence of TiO2 particles. The effect of pH as well as of the semiconductor particles on the kinetics and products of the reaction was observed. Formation of nitrophenols is enhanced at acidic pH, due to thermal processes initiated by nitrous acid, as well as in the presence of TiO2, due to the photocatalytic oxidation of nitrite.

Phenol photonitration upon UV irradiation of nitrite in aqueous solution I: effects of oxygen and 2-propanol

Nitrophenols are formed in aqueous solution upon UV irradiation of phenol and nitrite. The formation of nitrophenols is enhanced by dissolved oxygen and inhibited by the addition of 2-propanol. The mechanism of phenol photonitration involves both .NO2 (or N2O4, reacting with phenol, and 4-nitrosophenol, which is oxidised to 4-nitrophenol. A reaction scheme is proposed based on experimental results.

Formation of nitrophenols upon UV irradiation of phenol and nitrate in aqueous solutions and in TiO2 aqueous suspensions

The formation of nitrophenols was studied as a consequence of ultra violet (UV) irradiation of aqueous solutions of phenol and nitrate in the range of pH 1-12. The study was performed both in homogeneous phase and in the presence of water-suspended TiO2. The effects of pH, dissolved oxygen and 2-propanol as .OH scavenger have been evaluated. A reaction mechanism is proposed, based on the experimental results.

New strategies for the determination of phenylurea pesticides by gas chromatography with hot splitless inlet systems

Direct gas chromatographic methods to analyse phenylurea pesticides are discouraged by the thermal instability of these compounds, that in conventional hot splitless inlet systems leads to extensive and irreproducible formation of isocyanates and amines. However a careful control of the operating conditions, like the inlet temperature, the pressure and the presence of suitable chemical additives (as acetic acid, low-molecular-mass amines, organic anhydrides) can either: (i) minimise the thermal decomposition enabling the direct GC-MS analysis of phenylureas, or (ii) lead to reproducible conversion to isocyanates. Experimental design was employed to study the effect of the experimental variables on the thermal transformation of phenylurea pesticides in splitless inlet system. Two strategies were alternatively optimised: (i) the minimisation of degradation reactions to increase the signal of phenylureas; (ii) the maximisation of the degradation to isocyanates that are in turn determined. The maximal yields in isocyanate were obtained with high inlet temperatures, low carrier flows in the injection phase and the presence of acetic anhydride. By contrast, the use of relatively low inlet temperatures, high carrier flows during the injection and the presence of an amine maximise the response of the parent compounds.