Cataract surgery and nonsteroidal antiinflammatory drugs

Nonsteroidal antiinflammatory drugs (NSAIDs) have become an important adjunctive tool for surgeons performing routine and complicated cataract surgery. These medications have been found to reduce pain, prevent intraoperative miosis, modulate postoperative inflammation, and reduce the incidence of cystoid macular edema (CME). Whether used alone, synergistically with steroids, or for specific high-risk eyes prone to the development of CME, the effectiveness of these medications is compelling. This review describes the potential preoperative, intraoperative, and postoperative uses of NSAIDs, including the potency, indications and treatment paradigms and adverse effects and contraindications. A thorough understanding of these issues will help surgeons maximize the therapeutic benefits of these agents and improve surgical outcomes.

FINANCIAL DISCLOSURE

Proprietary or commercial disclosures are listed after the references.

Phacoemulsification of the rock-hard dense nuclear cataract: Options and recommendations

We describe the essential steps in the successful phacoemulsification of the rock-hard, dense cataract. Appropriate and directed preoperative history, physical examination, and diagnostics allow the surgeon to select the best incision, anesthesia, and intended surgical technique for a given dense nuclear challenge. Hard nucleus-specific approaches for hydrodissection, pupil management, and zonular protection then allow the surgeon to approach the rock-hard nucleus with maximum safety. Dense nuclear dismantling options are then discussed in detail along with fluidic and power modulation considerations. Various specific phacoemusification machine settings for rock-hard cataracts from the authors representing several different phaco systems are then presented. The combination of these steps and considerations allow a more successful dense cataract removal and potential restoration of vision for patients. This paper represents the collective experience and advice of the Challenging and Complex Cataract Surgery Subcommittee.

Cataract surgery in the small eye

The surgical management of cataract in the small eye presents the ophthalmic surgeon with numerous challenges. An understanding of the anatomic classification in addition to a thorough preoperative assessment will help individualize each case and enable the surgeon to better prepare for the obstacles that might be encountered during surgery. Small eyes are especially challenging in terms of intraocular lens (IOL) calculations and possible current limitations of available IOL powers, which could necessitate alternative means of achieving emmetropia. Surgical strategies for minimizing complications and maximizing good outcomes can be developed from knowledge of the anatomic differences between various small-eye conditions and the pathologies that may be associated with each. A thorough understanding of the challenges inherent in these cases and the management of intraoperative and postoperative complications will ensure that surgeons approaching the correction of these eyes will achieve the best possible surgical results.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Targeted Next-Generation Sequencing Analysis of a Pendred Syndrome-Associated Thyroid Carcinoma

Pendred syndrome is an autosomal recessive disorder characterized by hearing loss and goiter and is caused by bi-allelic mutations (homozygous or compound heterozygous) of the PDS (SLC26A4) gene. The incidence of Pendred syndrome is 7.5-10/100,000 in the general population, and it carries a 1 % risk of developing thyroid carcinoma. Herein, we report a case of a patient with Pendred syndrome who developed a follicular variant of papillary thyroid carcinoma (FVPTC)-that is approximately at an odd of 1/1,000,000. Targeted next-generation sequencing with ThyroSeq v2 was performed on the tumor, and only a TP53 mutation (TP53 p.R175H) was identified. The mutation was limited to the tumor nodule of FVPTC as shown by immunohistochemistry. This report represents the first extensive molecular study of a Pendred syndrome-associated thyroid carcinoma. The evidences support that thyroid carcinomas arising from dyshormonogenetic goiter require additional genetic alteration in addition to the purported thyroid-stimulating hormone (TSH) overstimulation. It is intrigue to note that the mutant p53 is involved in the development of a low-grade malignant thyroid tumor as FVPTC in this patient.

Metabolism of classical cannabinoids and the synthetic cannabinoid JWH-018

Although the putative pharmacological targets of synthetic cannabinoids (SCBs) abused in "K2" and "Spice" are similar to Δ(9) -tetrahydrocannabinol (Δ(9) -THC), it remains unclear why SCB toxicity is similar yet different from marijuana. There are obvious potency and efficacy differences, but also important metabolic differences that help explain the unique adverse reactions associated with SCBs. This brief review discusses the limited research on the metabolism of the SCB JWH-018 and contrasts that with the metabolism of Δ(9) -THC.

[Emergent drugs (III): hallucinogenic plants and mushrooms]

An increase in the consumption of vegetable substances with a hallucinogenic effect has been observed. Some of these substances are associated with ancestral religious ceremonies, while many of them are legal or are partially regulated. Salvia divinorum is a powerful kappa receptor agonist, with dissociative and hallucinogenic properties, which start quickly and have a short duration. Kratom (Mytragyna speciosa) has mitragynine as its principal alkaloid, with stimulating effects at low doses (coke-like effect), and sedative effects (opiate-like effect) at high doses. Several deaths from its consumption have been detected. The consumption of hallucinogenic mushrooms appears in cyclic form, although there has been increase in their online offer. They are consumed in search of their hallucinogenic effects, above all those belonging to the family of psilocybes, which contain tryptamines with a hallucinogenic effect similar to LSD. Peyote (Lophophora psilocybes), a cactus rich in mescaline (trimetoxifeniletilamina), produces hallucinations of the five senses, and forms part of the religious culture of the North American Indians. Daturas, which are ubiquitous, produce anticholinergic symptoms and effects on the central nervous system (delirium, hallucinations, etc.), due to their high atropine and scopolamine content. Other substances used for their hallucinogenic effects include the drink known as ayahuasca, and seeds for preparing infusions like Ololiuqui, Morning Glory (Ipomoea violacea), Hawaian Baby Woodrose (Argyreia nervosa), Syrian Rue (Peganum harmala) and Iboga Rootbark (Tabernanthe iboga).

Retained drugs in the gastrointestinal tracts of deceased victims of oral drug overdose

CONTEXT

The extent of non-absorbed drug burden in the GI tract following overdose is unknown. Patients who present with clinical signs of toxicity may not undergo decontamination due to assumption that the drug has already been completely absorbed and because of limited scientific evidence of benefit for routine GI decontamination in poisoned patients.

OBJECTIVE

The goal of this study was to assess whether people who die of an oral overdose have unabsorbed drug present in the GI tract. The secondary goal was to analyze pharmacologic characteristics of retained drugs when present.

MATERIALS AND METHODS

Retrospective review of autopsy reports from 2008 to 2010, whose cause of death was determined as "intoxication" or "overdose, was performed at the Office of Chief Medical Examiner of the City of New York (OCME NYC)." Decedents of all ages were identified via electronic OCME database. Inclusion criteria were as follows: 1) cause of death "intoxication" or "overdose" noted by forensic autopsy, 2) ingestion of a solid drug formulation.

RESULTS

92 out of 1038 autopsies (9%) that met inclusion criteria had documentation of retained pill fragments, granules, paste, sludge, slurry, or whole pills in the GI tract. The most common drugs found were opioids and anticholinergics. Ninety-eight percent (98%) of the retained drugs were either modified-release preparations or drugs known to slow GI transit. Most decedents were dead on arrival; there were twelve in-hospital deaths and eleven patients died in the Emergency Department. Bupropion and venlafaxine were responsible for four deaths in those who received medical care. One person died in the ICU following bupropion ingestion.

DISCUSSION AND CONCLUSION

Overdose of an oral drug that either has modified-release properties or slows GI tract motility may result in substantial unabsorbed drug burden remaining in the GI tract.

Effects of hydroxocobalamin on carboxyhemoglobin measured under physiologic and pathologic conditions

CONTEXT

Pre-hospital administration of hydroxocobalamin (B12a) is used for empiric treatment of cyanide poisoning because cyanide poisoning is difficult to identify and requires immediate treatment. B12a interferes with the accuracy of several blood laboratory tests. This study aimed to explore how B12a affects carboxyhemoglobin (COHb) measurements in human blood at both physiologic and pathologic COHb levels.

METHODS

Several clinically relevant concentrations of B12a were added to human blood samples containing physiologic (∼ 3%) and pathologic (30% and 50%) COHb levels. We then measured the COHb levels of the samples using two different co-oximeters, the Radiometer ABL 700 and the Rapidpoint 500, and compared to their actual baseline COHb levels.

RESULTS

B12a had minimal effects on the COHb measured at both physiologic and pathologic levels when measured on the Radiometer. In contrast, the Rapidpoint B12a caused a dose-dependent decrease in the COHb measured, especially of pathologic COHb levels (∼ 30 and 50%).

CONCLUSION

The magnitude of B12a interference on measured COHb is dependent upon the specific co-oximeter used, the actual COHb level and the serum B12a concentration. These errors may potentially influence clinical decision making and thus affect patient outcomes. Our findings emphasize the importance of measuring COHb levels on blood samples collected prior to B12a administration.

A case of acute cerebral ischemia following inhalation of a synthetic cannabinoid

OBJECTIVE

Synthetic cannabinoids are increasingly used in the United States as marijuana substitutes. However, reports of severe toxicity, resulting from their use, are limited. We present the case of acute cerebral infarction following synthetic cannabinoid inhalation.

CASE REPORT

A 33-year-old man with no significant medical history presented at the emergency department with right-sided weakness and aphasia. He had smoked a synthetic cannabinoid (SC) product called "WTF" prior to the onset of symptoms. Physical examination showed right hemiparesis, dysarthria, and aphasia. Laboratory evaluation, electrocardiography, and computed tomography (CT) of the head were unremarkable. Following administration of intravenous tissue plasminogen activator, his symptoms improved. A repeat head CT showed acute infarction in the left insular cortex. His hypercoagulability panel was unremarkable, and the patient was discharged neurologically intact. Urine toxicology results were unremarkable. Analysis of the product by gas chromatography-mass spectrometry (GC-MS) procedure confirmed the presence of a synthetic cannabinoid known as XLR-11.

CONCLUSION

XLR-11 has previously been associated with acute kidney injury in humans. However, there are no reports of it causing acute cerebral ischemic events. The close temporal association between XLR-11 inhalation and his stroke is concerning. Acute cerebral infarction may occur after XLR-11 use in healthy patients.

Extracorporeal treatment for acetaminophen poisoning: recommendations from the EXTRIP workgroup

BACKGROUND

The Extracorporeal Treatments in Poisoning (EXTRIP) workgroup was created to provide evidence-based recommendations on the use of extracorporeal treatments (ECTR) in poisoning and the results are presented here for acetaminophen (APAP).

METHODS

After a systematic review of the literature, a subgroup selected and reviewed the articles and summarized clinical and toxicokinetic data in order to propose structured voting statements following a pre-determined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements, and the RAND/UCLA Appropriateness Method was used to quantify disagreement. Following discussion, a second vote determined the final recommendations.

RESULTS

Twenty-four articles (1 randomized controlled trial, 1 observational study, 2 pharmacokinetic studies, and 20 case reports or case series) were identified, yielding an overall very low quality of evidence for all recommendations. Clinical data on 135 patients and toxicokinetic data on 54 patients were analyzed. Twenty-three fatalities were reviewed. The workgroup agreed that N-acetylcysteine (NAC) is the mainstay of treatment, and that ECTR is not warranted in most cases of APAP poisoning. However, given that APAP is dialyzable, the workgroup agreed that ECTR is suggested in patients with excessively large overdoses who display features of mitochondrial dysfunction. This is reflected by early development of altered mental status and severe metabolic acidosis prior to the onset of hepatic failure. Specific recommendations for ECTR include an APAP concentration over 1000 mg/L if NAC is not administered (1D), signs of mitochondrial dysfunction and an APAP concentration over 700 mg/L (4630 mmol/L) if NAC is not administered (1D) and signs of mitochondrial dysfunction and an APAP concentration over 900 mg/L (5960 mmol/L) if NAC is administered (1D). Intermittent hemodialysis (HD) is the preferred ECTR modality in APAP poisoning (1D).

CONCLUSION

APAP is amenable to extracorporeal removal. Due to the efficacy of NAC, ECTR is reserved for rare situations when the efficacy of NAC has not been definitively demonstrated.

Chronic hematuria and abdominal pain

An 18-year-old Asian woman with a history of substance abuse presented to the Emergency Department with right-sided abdominal pain and hematuria of several months duration. Physical examination revealed right upper quadrant and suprapubic tenderness. Liver function tests were normal. Urinalysis showed: large blood, 30-50 red blood cells/high-powered field, and no bacteria. She underwent a CT of the abdomen and pelvis following oral and intravenous contrast.

Hemodialysis clearance of glyphosate following a life-threatening ingestion of glyphosate-surfactant herbicide

CONTEXT

Ingestion of glyphosate-surfactant herbicides (GlySH) can result in acute kidney injury, electrolyte abnormalities, acidosis, cardiovascular collapse, and death. In severe toxicity, the use of hemodialysis is reported, but largely unsupported by kinetic analysis. We report the dialysis clearance of glyphosate following a suicidal ingestion of a glyphosate-containing herbicide.

CASE DETAILS

A 62-year-old man was brought to the emergency department (ED) 8.5 h after drinking a bottle of commercial herbicide containing a 41% solution of glyphosate isopropylamine, in polyoxyethyleneamine (POEA) surfactant and water. He was bradycardic and obtunded with respiratory depression necessitating intubation and mechanical ventilation. Initial laboratory results were significant for the following: pH, 7.11; PCO2, 64 mmHg; PO2, 48 mmHg; potassium, 7.8 mEq/L; Cr 3.3, mg/dL; bicarbonate, 22 mEq/L; anion gap, 18 mEq/L; and lactate, 7.5 mmol/L. Acidosis and hyperkalemia persisted despite ventilation and fluid resuscitation. The patient underwent hemodialysis 16 h post ingestion, after which he demonstrated resolution of acidosis and hyperkalemia, and improvement in clinical status. Serum glyphosate concentrations were drawn prior to, during, and after hemodialysis. The extraction ratio and hemodialysis clearance were calculated to be 91.8% and 97.5 mL/min, respectively.

DISCUSSION

We demonstrate the successful clearance of glyphosate using hemodialysis, with corresponding clinical improvement in a patient with several poor prognostic factors (advanced age, large volume ingested, and impaired consciousness). The effects of hemodialysis on the surfactant compound are unknown. Hemodialysis can be considered when severe acidosis and acute kidney injury complicate ingestion of glyphosate-containing products.

[Emergent drugs (II): the Pharming phenomenon]

The use of medicines, with or without medical prescription, for recreational ends by the young population has received little attention from doctors. In the USA, one in five adolescents has used medicines for recreational purposes, and consultations in Emergency Departments for medicine abuse have exceeded those for illegal drugs. Although few data are available in Spain, such consumption is situated between 3.1 and 8.6% according to surveys. The medicines most used are dextromethorphan and methylphenidate. The former, on sale without prescription, presents a varied symptomatology, dosage and dependent metabolic action, ranging from euphoria to hallucinations. Methylphenidate, taken orally, nasally or intravenously, is used as a stimulant in substitution for cocaine and is one of the medicines most diverted onto the illicit market at the world level. In principle, other substances like modafinil and propofol present a limited incidence of non-medical use, but they have a probable abuse potential that should be borne in mind, above all in the health context. Finally, opiates like fentanyl, oxycodone and buprenorphine, with new pharmaceutical presentations, have recently become generalized in the therapeutic arsenal of many medical specialities; they are giving rise to phenomena of abuse, dependence and diversion towards the illicit market. Demands for detoxification treatment, their mixture with illegal substances, and cases of death should alert us to the abuse of these medicines.

Treating acetaminophen overdose: thresholds, costs and uncertainties

The United Kingdom's Medicines and Healthcare Products Regulatory Agency (MHRA) modified the indications for N-acetylcysteine therapy of acetaminophen (paracetamol) overdose in September 2012. The new treatment threshold line was lowered to 100 mg/L (662 μmol/L) for a 4 hours acetaminophen concentration from the previous 200 mg/L (1325 μmol/L). This decision has the potential to substantially increase overall costs associated with acetaminophen overdose with unclear benefits from a marginal increase in patients protected from hepatotoxicity, fulminant hepatic failure, death, or transplant. Changing the treatment threshold for acetaminophen overdose also implies that ingestion amounts previously thought not to require acetaminophen concentration measurements would need to be revised. As a result, more individuals will be sent to hospitals in order that everyone with a predicted 4 hours concentration above the 100 mg/L line will have concentrations measured and potentially be treated with N-acetylcysteine. Before others consider adopting this new treatment guideline, formal cost-effectiveness analyses need to be performed to define the appropriate thresholds for referral and treatment.

Ocular zoonotic onchocerca infection in a resident of Oregon

A long, slender filarial nematode was removed from the left anterior chamber of a resident of Oregon after several days of pain and blurred vision. The worm was identified as an Onchocerca, but it could not be further identified. This worm is the third zoonotic Onchocerca removed from the anterior chamber and the second case reported from the United States. Cases of zoonotic onchocerciasis continue to garner attention, and those cases affecting the eye are of particular interest.

Severe toxicity following synthetic cannabinoid ingestion

OBJECTIVE

To report a case of seizures and supraventricular tachycardia (SVT) following confirmed synthetic cannabinoid ingestion.

BACKGROUND

Despite widespread use of legal synthetic cannabinoids, reports of serious toxicity following confirmed use of synthetic cannabinoids are rare. We report severe toxicity including seizures following intentional ingestion of the synthetic cannabinoid JWH-018 and detail confirmation by laboratory analysis.

CASE REPORT

A healthy 48 year old man had a generalized seizure within thirty minutes of ingesting an ethanol mixture containing a white powder he purchased from the Internet in an attempt to get high. Seizures recurred and abated with lorazepam. Initial vital signs were: pulse, 106/min; BP, 140/88 mmHg; respirations, 22/min; temperature, 37.7 °C. A noncontrast computed tomography of the brain and EEG were negative, and serum chemistry values were normal. The blood ethanol concentration was 3.8 mg/dL and the CPK 2,649 U/L. Urine drug screening by EMIT was negative for common drugs of abuse, including tetrahydrocannabinol. On hospital day 1, he developed medically refractory SVT. The patient had no further complications and was discharged in his normal state of health 10 days after admission. The original powder was confirmed by gas chromatography mass spectrometry to be JWH-018, and a primary JWH-018 metabolite was detected in the patient's urine (200 nM) using liquid chromatography tandem mass spectrometry.

DISCUSSION

Synthetic cannabinoids are legal in many parts of the world and easily obtained over the Internet. Data on human toxicity are limited and real-time confirmatory testing is unavailable to clinicians. The potential for toxicity exists for users mistakenly associating the dose and side effect profiles of synthetic cannabinoids to those of marijuana.

CONCLUSION

Ingestion of JWH-018 can produce seizures and tachyarrhythmias. Clinicians, lawmakers, and the general public need to be aware of the potential for toxicity associated with synthetic cannabinoid use.

Inconsistent approach to the treatment of chronic digoxin toxicity in the United States

Evidence-based guidelines do not exist for the treatment of patients with chronic mild—moderate digoxin toxicity. We sought to evaluate differences among specialists in the use of digoxin-specific antibody fragments and the decision to admit these patients. A sample of cardiologists, emergency physicians, and medical toxicologists was surveyed. The survey detailed four hypothetical cases of chronic digoxin toxicity created by consensus among authors. All cases had the same digoxin concentration, but signs and symptoms varied in an attempt to explore four different thresholds. For each scenario, clinicians made decisions about admission and treatment. Survey response varied: cardiologists 17%, emergency physicians 6.7%, and toxicologists 39%. Statistically significant difference was found in the administration of Fab among cardiologists (67%), emergency physicians (82%), or toxicologists (91.5%) and admission rate (cardiologists 34%, emergency physicians 28%, and toxicologists 46%). Differences exist among clinicians of various specialties regarding treatment of chronic digoxin toxicity. These differences may reflect diverse perspectives or knowledge gaps and may translate into excess cost or less than ideal care. Exploring these differences may improve patient care, improve interactions among providers, and set the stage for development of consensus guidelines and research.

Use of pralidoxime without atropine in rivastigmine (carbamate) toxicity

Some experimental models suggest that the use of pralidoxime in carbamate toxicity is deleterious. Although pretreatment with atropine minimizes the adverse effect of pralidoxime reported in these models, concerns over the risks of pralidoxime in humans with carbamate poisoning continue. We present a unique case of carbamate toxicity treated successfully with pralidoxime alone. An 80-year-old woman with Alzheimer's dementia presented to the emergency department with 3-4 days of lightheadedness, vomiting, diarrhea, and bilateral lower extremity muscle pain. Extensive review of systems was otherwise negative. Her vital signs were BP, 207/85 mmHg; pulse, 101 beats/min; rectal temperature, 36.6( degrees )C; respirations, 18/min; and SpO(2), 95% breathing room air. Her bedside glucose measurement was 6.7 mmol/L. Physical examination revealed a confused, diaphoretic, ill-appearing woman with miosis and fasciculations of the tongue, eyelids, gastrocnemius and quadriceps bilaterally. The heart, lung, abdominal and head, eyes, ears, nose and throat examinations were otherwise unremarkable. Nine 5-cm(2) rivastigmine patches (9.5 mg/24-hour) were found adherent to her torso and lower extremities. The patches were immediately removed and underlying skin cleansed with soap and water. Laboratory values including complete blood count, basic metabolic panel, calcium, magnesium, phosphorus, troponin, coagulation studies and urinalysis were unremarkable. Due to the absence of pulmonary muscarinic findings, no atropine was administered. However, 1 g of pralidoxime was administered intravenously over 30 min to treat fasciculations. Within 30 min of this treatment, there was significant improvement in symptoms and resolution of fasciculations. She was admitted to the hospital, required no further pralidoxime therapy and was discharged after 3 days. Rivastigmine is a reversible (carbamate) cholinesterase inhibitor used to treat dementia. In overdose, cholinergic crisis is expected and in this case was precipitated by patch overuse. We believe there was a causal relationship between pralidoxime administration and the prompt resolution of symptoms and fasciculations. This case of apparently safe and effective pralidoxime use without concomitant atropine administration in a patient with carbamate toxicity reinforces recent data demonstrating the potential safety of pralidoxime in carbamate toxicity.

Profile of clear corneal cataract incisions demonstrated by ocular coherence tomography

PURPOSE

To examine the profile of clear corneal cataract incisions in the living eye using optical coherence tomography (OCT).

SETTING

Private practice, Eugene, Oregon, USA.

METHODS

The Zeiss Visante OCT anterior segment imaging system was used to study the profile of clear corneal cataract incisions, all in senior citizens. The OCT images of the operative eye were taken on the first postoperative day approximately 24 hours after surgery. The OCT images of clear corneal incisions were compared with an OCT image of a control eye, incisions without stromal hydration, and previous drawings of clear corneal incisions.

RESULTS

In the images, the clear corneal incisions had an arcuate configuration rather than a straight line configuration, as previously indicated. This architecture appears to add greater stability as a result of a tongue-and-groove-like fit of the floor to the roof of the incision as well as an incision that is longer than the chord length that had previously been measured. Other findings include that stromal swelling, which facilitates sealing of these incisions by the endothelial pump, lasted for at least 24 hours.

CONCLUSIONS

Results indicate an incision in the plane of the cornea with a chord length of at least 2.0 mm provides advantageous architecture for adequate self-sealing. Proper clear corneal incision construction resulted in an incision architecture that seemed to have increased stability and added safety, contributing to an absence of endophthalmitis for more than 10 years and 9000 cases in a single practice.

Contrast sensitivity and measuring cataract outcomes

Clinical research has demonstrated the the continuous decline of the contrast sensitivity with age results from increasing spherical aberration of the human crystalline lens. Replacing the crystalline lens with appropriate modeled pseudophakic lens can provide superior contrast sensitivity and functional vision. As advances in the technology allow cataract and refractive surgeons to address higher-order optical aberrations, the measurement of functional vision becomes increasingly critical as a gauge of the progress. Contrast sensitivity testing is assuming a prominent place in the evaluation of surgical modalities because it reflects functional vision, correlates with visual performance, and provide a key to understanding optical and visual processing of images.

Scleral fixation without conjunctival dissection

Scleral fixation of intraocular lenses (IOLs) and adjunctive capsular devices can be performed under the protection of a scleral flap. A modification of this technique uses a scleral pocket initiated through a peripheral clear corneal incision. Full-thickness passage of a double-armed suture through the scleral pocket and conjunctiva, with subsequent retrieval of the suture ends through the external incision for tying, facilitates scleral fixation. This modification offers several advantages over traditional methods: It eliminates the need for conjunctival dissection and scleral cauterization; a scleral pocket affords a greater surface area for suture placement through an ab externo or ab interno approach; retrieval of the sutures through the external corneal incision and subsequent tying allows the suture knot to pass under the protective roof of the scleral pocket, negating the need for suture knot rotation; and the architecture of the scleral pocket eliminates the need for sutured wound closure. Suture retrieval and scleral fixation through a corneoscleral pocket offers a refined method for fixation of IOLs and other intraocular adjunctive devices.

Scleral fixation using suture retrieval through a scleral tunnel

Scleral fixation of intraocular lenses (IOLs) can be performed under the protection of a scleral flap. A variation of this technique uses a scleral tunnel for suture fixation to the eye. Passage of a double-armed suture through the roof of the scleral tunnel with subsequent retrieval of the suture ends through the external incision for tying facilitates scleral fixation. This modification offers several advantages: A scleral tunnel is easier to construct than a triangular flap and does not require suture closure. It affords a greater surface area for suture placement through an ab externo or ab interno approach. Tying each suture allows the suture knot to pass under the roof of the tunnel, eliminating the need for suture knot rotation. Suture retrieval and scleral fixation through a scleral tunnel incision offers a simplified and elegant method for fixation of IOLs and other intraocular adjunctive devices.

Intraocular pressure during phacoemulsification

PURPOSE

To assess changes in intraocular pressure (IOP) during standard coaxial or bimanual microincision phacoemulsification.

SETTING

Oregon Eye Center, Eugene, Oregon, USA.

METHODS

Bimanual microincision phacoemulsification (microphaco) was performed in 3 cadaver eyes, and standard coaxial phacoemulsification was performed in 1 cadaver eye. A pressure transducer placed in the vitreous cavity recorded IOP at 100 readings per second. The phacoemulsification procedure was broken down into 8 stages, and mean IOP was calculated across each stage. Intraocular pressure was measured during bimanual microphaco through 2 different incision sizes and with and without the Cruise Control (Staar Surgical) connected to the aspiration line.

RESULTS

Intraocular pressure exceeded 60 mm Hg (retinal perfusion pressure) during both standard coaxial and bimanual microphaco procedures. The highest IOP occurred during hydrodissection, ophthalmic viscosurgical device injection, and intraocular lens insertion. For the 8 stages of the phacoemulsification procedure delineated in this study, IOP was lower for at least 1 of the bimanual microphaco eyes compared with the standard coaxial phaco eye in 4 of the stages (hydro steps, nuclear disassembly, irritation/aspiration, anterior chamber reformation).

CONCLUSION

There was no consistent difference in IOP between the bimanual microphaco eyes and the eye that had standard coaxial phacoemulsification. Bimanual microincision phacoemulsification appears to be as safe as standard small incision phacoemulsification with regard to IOP.

Clinical evaluation of the Crystalens AT-45 accommodating intraocular lens

PURPOSE

To evaluate the 12-month U.S. phase II clinical trial results of the Crystalens AT-45 (eyeonics, Inc.) intraocular lens (IOL) used to provide uncorrected distance, intermediate, and near visual acuities in patients having cataract extraction and to compare in a substudy the contrast sensitivity and near visual acuity in patients with the Crystalens AT-45 IOL and those receiving a standard IOL.

SETTING

Fourteen clinical sites throughout the U.S. for efficacy and 3 non-U.S. sites for safety and efficacy.

METHODS

Patients 50 years or older had small-incision cataract extraction with implantation of the Crystalens AT-45 IOL. Unilateral implantation was followed by fellow-eye implantation. Postoperatively, uncorrected distance, near, and intermediate visual acuities were determined. Near and intermediate visual acuities were tested through a distance correction to eliminate potential pseudoaccommodative effects of residual myopia and corneal cylinder. A substudy tested contrast sensitivity under mesopic conditions with and without glare, as well as visual acuity in a subset of Crystalens AT-45 patients and a control group receiving a standard IOL.

RESULTS

A total of 263 patients participated in the U.S. clinical trial and had 1 year of follow-up. Near visual acuities through the distance correction of 20/40 (J3) or better, monocularly and bilaterally, respectively, were seen in 90.1% and 100%; intermediate near visual acuities were seen in 99.6% and 100%. More than half the bilaterally implanted Crystalens AT-45 patients achieved uncorrected near acuity of 20/25 (J1) or better through the distance correction, and 84% achieved 20/32 (J2) or better. In the substudy, monocular near vision through the distance correction of 20/25 (J1) or better was seen in 50.4% with the Crystalens AT-45 IOL and in 4.7% with the standard IOLs. Mesopic contrast sensitivity results with and without glare for the Crystalens AT-45 were similar to those with standard monofocal IOLs. Nearly all patients (74 patients; 97.3%) who bilaterally were within 0.50 diopter of plano postoperatively achieved 20/32 (J2) or better uncorrected near, intermediate, and distance visual acuities.

CONCLUSIONS

The Crystalens AT-45 accommodating IOL provided good uncorrected near, intermediate, and distance vision in pseudophakic patients. Contrast sensitivity with the Crystalens AT-45 was not diminished relative to standard monofocal IOLs, and near and intermediate visual performance was significantly better than with standard IOLs.