Ocular surgical pharmacology: corneal endothelial safety and toxicity

Toxic anterior segment syndrome and Urrets-Zavalia syndrome: Spectrum of the same entity?

PURPOSE

The purpose of the study was to analyze the outcomes of patients with toxic anterior segment syndrome (TASS) and Urrets-Zavalia (UZ) syndrome.

MATERIALS AND METHODS

The records of all patients with TASS and UZ syndrome were studied. Corrected distance visual acuity (CDVA), intraocular pressure (IOP), and the details of surgeries performed were recorded at 1 and 3 months. We studied the changes in CDVA and IOP using repeated-measure ANOVA and paired t -test, respectively.

RESULTS

Four patients (44.4%) developed refractory UZ syndrome, and five (55.6%) patients had TASS. At the end of 3 months of follow-up, all nine patients had concentric rings of iris atrophy and corneal edema. None of the cases had hypopyon or vitritis. Peripheral anterior synechiae (PAS) with secondary glaucoma was present only in cases of UZ syndrome. Among the four cases of UZ syndrome, goniosynechialysis was performed for 2 cases and trabeculectomy for one case. Despite these interventions, IOP could not be controlled. Patients in the TASS group did not exhibit PAS formation, and IOP was normal, but corneal edema and concentric rings of iris atrophy persisted. Descemet's stripping endothelial keratoplasty was performed for all the TASS cases. There was a statistically significant drop in CDVA (P = 0.028) and an increase in IOP (P = 0.029) at 3-month postcataract surgery.

CONCLUSION

TASS and UZ syndrome could result in sight-threatening complications. They may be considered diseases of the same entity as both the conditions were found in the same cluster. TASS could be considered as an abortive attack of UZ syndrome.

Postoperative Endophthalmitis and Toxic Anterior Segment Syndrome Prophylaxis: 2020 Update

Improved surgical techniques have led to an increase in the number of outpatient ophthalmic procedures. In spite of decreased surgical times and overall improved outcomes, endophthalmitis remains one of the most severe complications of ophthalmic surgery. Although there are well known risk factors for postoperative endophthalmitis, some prophylaxis strategies remain controversial. A category of noninfectious postoperative inflammation, known as toxic anterior segment syndrome (TASS), is a rare but important complication of cataract surgery. While several worldwide outbreaks of TASS have occurred, it is challenging to identify an etiology in order to reduce the risk of further cases. Endophthalmitis and TASS cannot be prevented completely, but their rates may be decreased through risk reduction strategies supported by peer-reviewed evidence. This review highlights the current evidence in the prevention strategies for postoperative endophthalmitis and TASS.

Toxic anterior segment syndrome: A review

Toxic anterior segment syndrome is a surgical complication characterized by a noninfectious anterior chamber inflammatory reaction having multiple etiologies. The clinical signs (prominent limbus-to-limbus corneal edema, anterior chamber inflammation) and symptoms (decreased visual acuity, discomfort) generally occur within the first 12-48 hours after intraocular surgery. Most patients achieve good clinical and visual outcomes when there is a prompt clinical diagnosis and adequate treatment. We review the literature on toxic anterior segment syndrome, emphasizing its etiology, pathophysiology, and clinical and surgical management, as well as prognosis and sequelae. Our goal is to reduce the frequency of toxic anterior segment syndrome by highlighting the importance of prevention, early recognition, and distinguishing toxic anterior segment syndrome from infectious endophthalmitis.

Toxic Anterior Segment Syndrome after Uncomplicated Cataract Surgery

Purpose

To evaluate the anterior segment examination findings and the response to medical therapy of patients who had toxic anterior segment syndrome (TASS) after uncomplicated cataract surgery.

Methods

Fourteen eyes of 14 patients were enrolled in the study. Visual acuity, biomicroscopic anterior segment examination, intraocular pressure measurement, and fundus examination were performed to assess TASS occurring during postoperative 12–48 hours after uncomplicated phaco surgery. The visual impairment, corneal edema, tyndallization, fibrin formation, hypopyon, vitritis, and response to steroid therapy were evaluated prospectively.

Results

After topical steroid therapy lasting for 1 week, visual acuity improved in 11 eyes. No significant visual improvement occurred in 3 eyes. Significant corneal edema was found in 4 and mild corneal edema was observed in the other 10 eyes. Fibrin reaction occurred in 5 and tyndallization in various degrees was positive in all eyes. There was a 1-mm hypopyon in 1 patient. There was no sign of vitritis and steroid therapy was effective in all of the patients. In addition to topical treatment with steroid and antibiotic drops; systemic and subconjunctival steroids were used in 3 patients who had fibrin formation and in one patient who had hypopyon.

Conclusions

After uncomplicated cataract surgery, toxic anterior segment may occur in the early postoperative period, which is treated successfully with steroids. More studies are needed to understand the multifactorial risk factors affecting the etiopathogenesis of this syndrome.

Safety of Using Matrix Metalloproteinase Inhibitor in Experimental Glaucoma Filtration Surgery

We evaluated the safety of matrix metalloproteinase (MMP) inhibitor in experimental glaucoma filtration surgery in an animal model. Fifteen New Zealand white rabbits underwent an experimental trabeculectomy and were randomly allocated into 3 groups according to the adjuvant agent: no treatment group (n = 5), 0.02% mitomycin C (MMC) soaking group (n = 5), and MMP inhibitor (ilomastat) subconjunctival injection group (n = 5). Slit lamp examination with Seidel testing, pachymetry, and specular microscopy was performed preoperatively and postoperatively. The conjunctiva and ciliary body toxicity were evaluated with scores according to the pathologic grading systems. Electron microscopy was used to examine the structural changes in cornea, conjunctiva, and ciliary body. In the ilomastat-treated group, there was no statistically significant change in central corneal thickness preoperatively and at 28 days postoperatively (P = 0.655). There were also no significant changes in specular microscopy findings over the duration of the study in the ilomastat-treated group. The conjunctival toxicity score was 1 in the control group, 1.5 in the ilomastat-treated group, and 2 in the MMC-treated group. When assessing ciliary body toxicity scores, the ilomastat-treated group score was 0.5 and the MMC-treated group score was 1.5. Transmission electron microscopy did not show structural changes in the cornea and ciliary body whereas the structural changes were noticed in MMC group. A single subconjunctival injection of MMP inhibitor during the experimental trabeculectomy showed a less toxic affect in the rabbit cornea, conjunctiva, and ciliary body compared to MMC.

Ability of Mn(2+) to Permeate the Eye and Availability of Manganese-enhanced Magnetic Resonance Imaging for Visual Pathway Imaging via Topical Administration

Background:

Manganese-enhanced magnetic resonance imaging (MEMRI) for visual pathway imaging via topical administration requires further research. This study investigated the permeability of the corneal epithelium and corneal toxicity after topical administration of Mn²⁺ to understand the applicability of MEMRI.

Methods:

Forty New Zealand rabbits were divided into 0.05 mol/L, 0.10 mol/L, and 0.20 mol/L groups as well as a control group (n = 10 in each group). Each group was further subdivided into epithelium-removed and epithelium-intact subgroups (n = 5 in each subgroup). Rabbits were given 8 drops of MnCl₂ in 5 min intervals. The Mn²⁺ concentrations in the aqueous and vitreous humors were analyzed using inductively coupled plasma-mass spectrometry at different time points. MEMRI scanning was carried out to image the visual pathway after 24 h. The corneal toxicity of Mn²⁺ was evaluated with corneal imaging and pathology slices.

Results:

Between the aqueous and vitreous humors, there was a 10 h lag for the peak Mn²⁺ concentration times. The intraocular Mn²⁺ concentration increased with the concentration gradients of Mn²⁺ and was higher in the epithelium-removed subgroup than that in the epithelium-intact subgroup. The enhancement of the visual pathway was achieved in the 0.10 mol/L and 0.20 mol/L epithelium-removed subgroups. The corresponding peak concentrations of Mn²⁺ were 5087 ± 666 ng/ml, 22920 ± 1188 ng/ml in the aqueous humor and 884 ± 78 ng/ml, 2556 ± 492 ng/ml in the vitreous body, respectively. Corneal injury was evident in the epithelium-removed and 0.20 mol/L epithelium-intact subgroups.

Conclusions:

The corneal epithelium is a barrier to Mn²⁺, and the iris and lens septum might be another intraocular barrier to the permeation of Mn²⁺. An elevated Mn²⁺ concentration contributes to the increased permeation of Mn²⁺, higher MEMRI signal, and corneal toxicity. The enhancement of the visual pathway requires an effective Mn²⁺ concentration in the vitreous body.

Effects of intracameral brilliant blue on the corneal endothelium of swine: in vitro study

Abstract: The aim was to investigate the ultrastructural changes in the corneal endothelium of pigs induced by intracameral 0.05% brilliant blue. Twenty swine corneas were separated into two groups, the right eye bulbs (control group) and the left eye bulbs (experimental group) of the same animal. All the eye bulbs were evaluated with specular microscopy. The cornea of the right eye bulbs was excised and in the left eye bulbs 0.2ml of 0.05% brilliant blue vital dye (OPTH-blue±) was injected into the anterior chamber, where it remained for one minute. Then the anterior chamber was cleaned with a balanced salt solution injection and the cornea was excised too. All the corneas were evaluated by scanning electron microscopy to evaluate the changes on the endothelium caused by the brilliant blue dye. There were no significant differences between the right corneal endothelium cells and the left corneal endothelium cells with scanning electron microscopy after intracameral use of 0.05% brilliant blue dye. The 0.05% brilliant blue dye concentration did not cause deleterious effects for the swine corneal endothelium after intracameral use and can be a choice for safe staining of the anterior capsule of the lens in cataract surgery.

Impact of Indocyanine Green Concentration, Exposure Time, and Degree of Dissolution in Creating Toxic Anterior Segment Syndrome: Evaluation in a Rabbit Model

Purpose. To investigate the role of indocyanine green (ICG) dye as a causative material of toxic anterior segment syndrome (TASS) in an experimental rabbit model. Method. Eight eyes of four rabbits were allocated to this study. Capsular staining was performed using ICG dye, after which the anterior chamber was irrigated with a balanced salt solution. The effects of different concentrations (control, 0.25, 0.5, and 1.0%), exposure times (10 and 60 seconds), and the degree of dissolution (differently vortexed) were investigated. The analysis involved anterior segment photography, ultrasound pachymetry, prostaglandin assay (PGE₂ Parameter Assay, R&D systems, Inc.), and scanning electron microscopy of each iris. Result. There was no reaction in the control eye. A higher aqueous level of PGE₂ and more severe inflammatory reaction were observed in cases of eyes with higher concentration, longer exposure time, and poorly dissolved dye. Additionally, scanning electron microscopy revealed larger and coarser ICG particles. Conclusion. TASS occurrence may be associated with the concentration, exposure time, and degree of dissolution of ICG dye during cataract surgery.

Historical Review and Update of Surgical Treatment for Corneal Endothelial Diseases

The cornea remains in a state of deturgescence, maintained by endothelial cell Na+/K+ ATPase and by tight junctions between endothelial cells that limit entrance of fluid into the stroma. Fuchs' endothelial corneal dystrophy (FECD) was initially described by Fuchs in 1910 as a combination of epithelial and stromal edema in older patients. It manifests as bilateral, albeit asymmetric, central corneal guttae, corneal edema, and reduced vision. When edema is severe, the corneal epithelium can detach from its basement membrane, creating painful bullae on the anterior surface of the cornea. The course of this dystrophy can be further accelerated after intraocular surgery, specifically cataract extraction. Pseudophakic bullous keratopathy (PBK) is endothelial cell loss caused by surgery in the anterior chamber. If the corneal endothelium is damaged during surgery, the same spectrum of symptoms as found in FECD can develop. In the nineteenth century, penetrating keratoplasty was the only surgical procedure available for isolated endothelial disease. In the 1960s, Dr. José Barraquer described a method of endothelial keratoplasty using an anterior approach via laser-assisted in situ keratomileusis (LASIK) flap. In 1999, Melles and colleague described their technique of posterior lamellar keratoplasty. Later, Melles et al. started to change host dissection using simple "descemetorhexis" in a procedure known as Descemet's stripping endothelial keratoplasty. Following the widespread adoption of Descemet's stripping automated endothelial keratoplasty, the Melles group revisited selective Descemet's membrane transplantation and reported the results of a new procedure, Descemet's membrane endothelial keratoplasty (DMEK). Recently, some eye banks have experimented with the preparation of DMEK/Descemet's membrane automated endothelial keratoplasty donor tissue that may help the surgeon avoid the risk of tissue loss during the stromal separation step. Recently, the authors described a new bimanual technique for insertion and positioning of endothelium-Descemet membrane grafts in DMEK.

Investigation of ocular events associated with taprenepag isopropyl, a topical EP2 agonist in development for treatment of glaucoma

PURPOSE

Taprenepag isopropyl is an EP2 receptor agonist that is in development for the treatment of glaucoma. Iritis, photophobia, and increased corneal thickness observed in a Phase 2 clinical trial with taprenepag isopropyl were not previously observed in topical ocular toxicity studies in rabbits and dogs. In vivo studies using cynomolgus monkeys and in vitro models were used to elucidate the mechanisms underlying these ocular events.

METHODS

Monkeys were dosed daily for 28 days in 1 eye with taprenepag and in the other with vehicle control. Complete ophthalmic examinations were performed at baseline and weekly thereafter. Serial sections of eyes were examined histopathologically at the end of the study. Recovery after the discontinuation of taprenepag was assessed for 28 days in the monkeys in the high-dose group. In vitro studies evaluated cell viability, paracellular permeability, and cytokine induction with human corneal epithelial or endothelial cell cultures.

RESULTS

Monkeys demonstrated a dose-related incidence of iritis and increased corneal thickness that resolved within 28 days of discontinuing taprenepag. There was no evidence in vivo of taprenepag toxicity to the corneal endothelium or epithelium. Cell viability of stratified epithelial cells was primarily affected by excipients and was similar to Xalatan(®). The viability of HCEC-12 cells was not affected by taprenepag at concentrations up to 100 μM.

CONCLUSIONS

The lack of in vivo or in vitro endothelial cytotoxicity and the reversibility of the increase in corneal thickness and iritis in the monkey provide confidence to permit further clinical development of taprenepag.

Eye

The Eye chapter of the 3rd edition of Haschek and Rousseaux’s Handbook of Toxicologic Pathology brings a comprehensive description of pathological processes affecting the ocular tissues in the most commonly used laboratory animals and their correlations with human diseases of interest in toxicology. Also presented are detailed descriptions of the structure and function of the different ocular tissues, the most advanced techniques applied in the toxicological evaluation of the eye, useful animal models of human disease, and known mechanisms of ocular toxicity. The introductory sections of the chapter also feature such essential topics as ocular embryology, an overview of clinical ophthalmic evaluation, and eye-specific techniques of tissue processing.

Toxic anterior segment syndrome after foldable artiflex iris-fixated phakic intraocular lens implantation

Toxic anterior segment syndrome (TASS) developed in four cases after uneventful implantation of a foldable iris-fixated phakic intraocular lens (pIOL). Two cases occurred sequentially in one patient. The TASS subsided without complications in all cases after intensive topical steroid treatment. A multitude of possible causes is considered for the occurrence of these TASS cases. From the sterilization and cleaning of surgical instruments to the possibility of endotoxines in ophthalmic viscosurgical devices (OVD). These rare cases should alert the surgeon to the possibility of TASS after pIOL implantation.

[Toxic anterior segment syndrome]

Toxic anterior segment syndrome (TASS) is a general term used to describe acute, sterile postoperative inflammation due to a non-infectious substance that accidentally enters the anterior segment at the time of surgery and mimics infectious endophthalmitis. TASS most commonly occurs acutely following anterior segment surgery, typically 12-72h after cataract extraction. Anterior segment inflammation is usually quite severe with hypopyon. Endothelial cell damage is common, resulting in diffuse corneal edema. No bacterium is isolated from ocular samples. The causes of TASS are numerous and difficult to isolate. Any device or substance used during the surgery or in the immediate postoperative period may be implicated. The major known causes include: preservatives in ophthalmic solutions, denatured ophthalmic viscosurgical devices, bacterial endotoxin, and intraocular lens-induced inflammation. Clinical features of infectious and non-infectious inflammation are initially indistinguishable and TASS is usually diagnosed and treated as acute endophthalmitis. It usually improves with local steroid treatment but may result in chronic elevation of intraocular pressure or irreversible corneal edema due to permanent damage of trabecular meshwork or endothelial cells.

Toxic anterior segment syndrome: common causes

PURPOSE

To identify the most common risk factors associated with toxic anterior segment syndrome (TASS).

SETTING

Ophthalmic surgical centers in the United States, Argentina, Brazil, Italy, Mexico, Spain, and Romania.

METHODS

A TASS questionnaire on instrument cleaning and reprocessing and extraocular and intraocular products used during cataract surgery was placed on the American Society of Cataract and Refractive Surgery web site. A retrospective analysis of questionnaires submitted by surgical centers reporting cases of TASS was performed between June 1, 2007, and May 31, 2009, to identify commonly held practices that could cause TASS. Members of the TASS Task Force made site visits between October 1, 2005, and May 31, 2009, and the findings were evaluated.

RESULTS

Data from 77 questionnaires and 54 site visits were analyzed. The reporting centers performed 50 114 cataract surgeries and reported 909 cases of TASS. From January 1, 2006, to date, the 54 centers reported 367 cases in 143 919 procedures; 61% occurred in early 2006. Common practices associated with TASS included inadequate flushing of phaco and irrigation/aspiration handpieces, use of enzymatic cleansers, detergents at the wrong concentration, ultrasonic bath, antibiotic agents in balanced salt solution, preserved epinephrine, inappropriate agents for skin prep, and powdered gloves. Reuse of single-use products and poor instrument maintenance and processing were other risk factors.

CONCLUSIONS

The survey identified commonly held practices associated with TASS. Understanding these findings and the safe alternatives will allow surgical center personnel to change their practices as needed to prevent TASS.

FINANCIAL DISCLOSURE

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

Toxic anterior segment syndrome after cataract surgery

We report a case of toxic anterior segment syndrome (TASS) that developed after cataract surgery. A 78-year-old woman had uneventful phacoemulsification via a clear corneal incision with implantation of an acrylic intraocular lens. One day postoperatively, diffuse corneal edema and anterior chamber inflammation were evident. Topical antibiotic and steroid eyedrops were prescribed. The anterior chamber reaction decreased considerably, but corneal edema persisted. After a thorough investigation, the antiseptic solution used to soak surgical instruments before subsequent surgery was identified as the source of the problem.

Cytotoxicity of ophthalmic solutions with and without preservatives to human corneal endothelial cells, epithelial cells and conjunctival epithelial cells

PURPOSE

The cytotoxicity of a range of commercial ophthalmic solutions in the presence and absence of preservatives was assessed in human corneal endothelial cells (HCECs), corneal epithelia and conjunctival epithelia using in vitro techniques.

METHODS

Cell survival was measured using the WST-1 assay for endothelial cells and the MTT assay for epithelial cells. Commercially available timolol, carteolol, cromoglicate, diclofenac, bromfenac and hyaluronic acid ophthalmic solutions were assessed for cytotoxicity in the presence and absence of preservatives. The preservatives benzalkonium, chlorobutanol and polysorbate were also tested. The survival of cells exposed to test ophthalmic solutions was expressed as a percentage of cell survival in the control solution (distilled water added to media) after 48 h exposure.

RESULTS

HCEC survival was 20-30% in ophthalmic solutions diluted 10-fold. The survival of HCEC was significantly greater in all solutions in the absence of preservative than in the presence of preservative. The survival of corneal and conjunctival epithelia was consistent with that of HCECs for all test ophthalmic solutions. The preservatives polysorbate and benzalkonium were highly cytotoxic with cell survival decreasing to 20% at the concentration estimated in commercial ophthalmic solutions. By comparison, the survival of cells exposed to chlorobutanol was 80% or greater.

CONCLUSIONS

The cytotoxicity of ophthalmic solutions to HCEC, corneal epithelia and conjunctival epithelia decreased in the absence of preservative.

Multistate outbreak of toxic anterior segment syndrome, 2005

PURPOSE

To present the findings of an outbreak of toxic anterior segment syndrome (TASS).

SETTING

Six states, 7 ophthalmology surgical centers, United States.

METHODS

Cases were identified through electronic communication networks and via reports to a national TASS referral center. Information on the procedure, details of instrument reprocessing, and products used during cataract surgery were also collected. Medications used during the procedures were tested for endotoxin using a kinetic assay.

RESULTS

The search identified 112 case patients (median age 74 years) from 7 centers from July 19, 2005, through November 28, 2005. Common presenting clinical features included blurred vision (60%), anterior segment inflammation (49%), and cell deposition (56%). Of the patients, 100 (89%) had been exposed to a single brand of balanced salt solution manufactured by Cytosol Laboratories and distributed by Advanced Medical Optics as AMO Endosol. Two patients continued to have residual symptoms. There were no reports of significant breaches in sterile technique or instrument reprocessing. Of 14 balanced salt solution lots, 5 (35%) had levels exceeding the endotoxin limit (0.5 EU/mL). Based on these findings, the balanced salt solution product was withdrawn, resulting in a termination of the outbreak.

CONCLUSIONS

This is the first known report of an outbreak of TASS caused by intrinsic contamination of a product with endotoxin. Ophthalmologists and epidemiologists should be aware of TASS and its common causes. To facilitate investigations of adverse outcomes such as TASS, those performing cataract surgeries should document the type and lot numbers of products used intraoperatively.

Corneal and conjunctival toxicity of disinfectants—Assessing safety for use with ophthalmic surgical instruments

We investigated the corneal toxicity of ortho-phthalaldehyde (Cidex OPA, Johnson and Johnson K.K.) and its predecessor glutaraldehyde (Cidex, Johnson and Johnson K.K.). We made primary cultures of porcine and human corneal endothelial cells. Commercially available cell lines were also used including human, bovine, and rabbit corneal epithelium and human conjunctival cells. Following incubation for two days, cell survival was measured using a WST-1 assay for endothelia and a MTT assay for the other cells. Test solutions included 2.25% and 3.5% glutaraldehyde and 0.55% ortho-phthalaldehyde. Cell survival was presented as a percentage of the control value. ortho-phthalaldehyde displayed less toxicity than glutaraldehyde for all cell types tested. As expected 3.5% glutaraldehyde was slightly more toxic than 2.25% glutaraldehyde. When primary human corneal endothelial cultures were exposed to ortho-phthalaldehyde, the survival rates were 88% for 100-fold dilutions and 95% for 500-fold dilutions. The survival rates for all cells tested were greater than 90% when dilutions of 1000-fold or more were used. In conclusion, the corneal toxicity of glutaraldehyde and ortho-phthalaldehyde appears to be within safe levels following washing procedures and therefore the use of these disinfectants may be suitable for selected ophthalmic surgical instruments in urgent or under-equipped circumstances.

A case of inadvertent anterior chamber and corneal stromal injection with antibiotics during cataract operation

PURPOSE

To report a case of inadvertent anterior chamber and cornea stromal injection with high dose antibiotics and steroids during cataract operation.

METHODS

During cataract operation on a 78 year-old female patient, high dose gentamicin (20 mg/0.5 ml) and dexamethasone (2 mg/0.5 ml) were inadvertently injected into the anterior chamber and cornea stroma when making cornea edema for sealing of the incision sites. Anterior chamber irrigation with balanced salt solution (BSS) was immediately administered. On postoperative day one, extensive cornea edema was noted, and best-corrected visual acuity was 0.2. Descemet's membrane folds were observed around the corneal incision sites. Topical 5% NaCl and 1% prednisolone were started.

RESULTS

Four weeks postoperatively, corneal edema began to reduce significantly. At four months postoperatively, corneal edema fully resolved, and best-corrected visual acuity was 0.8. However, some Descemet's membrane folds still remained, and a decrease in the number of endothelial cells was noted by specular microscope.

CONCLUSIONS

In this case involving anterior chamber and cornea stromal injection with high dose antibiotics and steroids, immediate anterior chamber irrigation with balanced salt solution seemed an appropriate management, and the patient's long-term visual acuity appears good. To prevent such mistakes, precise labeling of all solutions and use of different syringe needles should be considered.

Safety and efficacy of topical anesthesia combined with a lower concentration of intracameral lidocaine in phacoemulsification

PURPOSE

To assess the safety and efficacy of phacoemulsification under a topical anesthesia combined with intracameral lidocaine 0.5%.

SETTING

Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan, China.

METHODS

A prospective randomized double-blind study was designed in which patients had phacoemulsification performed under topical anesthesia (4 drops of nonpreserved lidocaine 2%) with 0.15 mL intracameral placebo (balanced salt solution) in 1 eye (Group 1) and topical anesthesia with intracameral nonpreserved lidocaine 0.5% in the other eye (Group 2). Endothelial changes, including cell density, coefficient variation of cell size, and percentage of hexagonal cells, were measured by noncontact specular microscopy. Preoperative and postoperative best corrected visual acuity was also documented. The degree of pain throughout surgery was ranked on a 10-point visual analog pain scale.

RESULTS

Thirty-three patients were recruited. There was no significant difference in preoperative and postoperative mean endothelial parameters between the 2 groups. Furthermore, mean endothelial cell loss was similar. Mild or no pain (score 0 to 1) was reported by 48.5% in Group 1 and 90.9% in Group 2. Patients reported less pain with combined topical and intracameral lidocaine anesthesia (P = .001, Mann-Whitney test). Vision was significantly improved in both groups. However, 1 patient in Group A developed vitreous loss as a result of involuntary eye movement.

CONCLUSION

Combining topical anesthesia with intracameral lidocaine 0.5% [corrected] anesthesia was safe and effective in phacoemulsification with intraocular lens implantation.

Pseudophakic corneal edema: A review of mechanisms and treatments

PURPOSE

To review the pathological mechanisms and treatments for pseudophakic corneal edema (PCE), one of the most common indications for penetrating keratoplasty.

METHODS

The literature was examined for the molecular biology associated with PCE and for the surgical and medical treatments for this disorder.

RESULTS

The incidence of PCE has recently been decreasing because of improved surgical instrumentation, including improvements in intraocular lens designs that cause less trauma to the corneal endothelium. Extracellular matrix and growth factor abnormalities occur in PCE corneas and recently, the role of aquaporins, which are involved in the regulation of fluid movement across cells, has been investigated.

CONCLUSIONS

Although newer treatment options have been suggested, penetrating keratoplasty still remains the most definitive treatment and has the highest success rate.

Toxic anterior segment syndrome—More than sterility meets the eye

TOXIC ANTERIOR SEGMENT SYNDROME (TASS) is a rare, potentially devastating complication of routine intraocular surgery that occurs when a noninfectious toxic agent enters the anterior segment of the eye, causing an inflammatory reaction. SEVERE CASES OF TASS can cause permanent harm, and if symptoms still are present after six weeks, the eye is not likely to recover. EARLY DIAGNOSIS AND TREATMENT are effective in preventing permanent damage, but often TASS is mistakenly diagnosed as infectious endophthalmitis for which treatment is completely different. THE CAUSES AND TREATMENT of TASS are discussed, and risk reduction strategies are described.

Outbreak of toxic anterior segment syndrome associated with glutaraldehyde after cataract surgery

PURPOSE

To present clinical findings of a cluster of cases of toxic anterior segment syndrome (TASS) after uneventful phacoemulsification cataract surgery.

SETTING

Department of Ophthalmology, Akdeniz University, Antalya, Turkey.

METHODS

Six eyes of 6 patients developed TASS after uneventful phacoemulsification cataract surgery with implantation of a 3-piece acrylic IOL performed by 2 ophthalmologists on the same day. Clinical findings included corneal edema, Descemet's membrane folds, anterior chamber reaction, fibrin formation, and irregular, dilated, and unreactive pupils.

RESULTS

Glutaraldehyde 2% solution was used inadvertently by the operating room staff who cleaned and sterilized reusable ocular instruments before autoclaving. None of the affected corneas improved. Additional surgical procedures were required and included penetrating keratoplasty, trabeculectomy, and glaucoma tube implantation.

CONCLUSIONS

Glutaraldehyde in concentrations generally used for cold sterilization is highly toxic to the corneal endothelium. The operating room staff involved in sterilizing instruments should be well educated about and careful to follow the protocols to properly clean and sterilize reusable ocular instruments.

Preoperative use of atropine to prevent intraoperative floppy-iris syndrome in patients taking tamsulosin

Intraoperative floppy-iris syndrome (IFIS) is a recently identified condition associated with phacoemulsification in patients using the alpha1-antagonist tamsulosin (Flomax). Patients with IFIS manifest a triad of symptoms during cataract surgery: fluttering and billowing of iris stroma due to normal fluid movement, propensity of iris prolapse to phaco and side-port incisions, and progressive constriction of the pupil. Prevention of IFIS by withdrawing tamsulosin preoperatively has not shown consistent benefit. We describe the preoperative administration of atropine, which effectively prevented the occurrence of IFIS in patients receiving tamsulosin.

Toxic anterior segment syndrome after Verisyse iris-supported phakic intraocular lens implantation

We report a case of toxic anterior segment syndrome (TASS) after implantation of a Verisyse (AMO) iris-supported phakic intraocular lens (IOL). The patient presented the day after surgery with significant decreased visual acuity and severe, persistent, limbus-to-limbus corneal edema. After treatment with topical steroids, oral steroids, nonsteroidal antiinflammatory agents, and hypertonic solution, the edema resolved over the course of 2 months and best corrected visual acuity improved to 20/20. Toxic anterior segment syndrome has been reported after implantation of IOLs previously, but this new case of TASS should alert surgeons to the possibility of the syndrome after phakic IOL placement.

Presence of mitomycin-C in the anterior chamber after photorefractive keratectomy

PURPOSE

To assess the presence of mitomycin-C (MMC) in hen aqueous humor after photorefractive keratectomy (PRK).

SETTING

Instituto Universitario de Oftalmobiología Aplicada, Faculty of Medicine, University of Valladolid, and Department of Analytical Chemistry, Faculty of Sciences, University of Valladolid, Valladolid, Spain.

METHODS

Mitomycin-C 0.02% was applied topically for 2 minutes to a right hen's eye after PRK (Group A) and to the left eye with intact epithelium (Group B). At different time points (10, 30, 60, 360, and 720 minutes), aqueous humor was extracted and high-performance liquid chromatography was performed to detect and quantify MMC levels.

RESULTS

The mean maximum drug concentration of MMC measured in the aqueous humor was 187.250 microg/L +/- 4.349 (SD) in Group A and 93.000 +/- 4.899 microg/L in Group B, both detected 10 minutes after topical application. Statistically significant differences were found between Groups A and B at 10, 30, and 60 minutes, with decreasing MMC levels in both groups but a higher concentration in Group A. After 360 minutes, MMC levels were undetectable in Group B and after 720 minutes in Group A.

CONCLUSIONS

Mitomycin-C was detectable in the aqueous humor of the hen eye after topical application in PRK-treated eyes and in eyes with intact epithelium. The presence of MMC is of concern as it may lead to ocular toxicity in the long term.

An outbreak of endophthalmitis after extracapsular cataract surgery probably caused by endotoxin contaminated distilled water used to dissolve acetylcholine

AIM

To study possible causes of an outbreak of severe endophthalmitis after planned extracapsular cataract surgery in Medan, Indonesia.

METHODS

In a 3 week period in November 2001, 17 of 43 patients developed signs of endophthalmitis after planned extracapsular cataract surgery. A search for possible causes was undertaken 4 months later.

RESULTS

In autoclaved stored distilled water used to dissolve acetylcholine (used in 16 of 17 patients with endophthalmitis) a high amount of endotoxin was detected in a human blood essay, as well as a small number of non-typeable Pseudomonas spp.

CONCLUSIONS

These findings suggest that distilled water used as solvent for acetylcholine was responsible for this outbreak of endophthalmitis. As a consequence, we now rely on solvents that are regularly checked for impurities such as an intravenous infusion fluid, rather than on vials with distilled water that is presumed to be sterile and kept for some time.

Toxic anterior segment syndrome

Toxic anterior segment syndrome (TASS) is a sterile postoperative inflammatory reaction caused by a noninfectious substance that enters the anterior segment, resulting in toxic damage to intraocular tissues. The process typically starts 12 to 48 hours after cataract/anterior segment surgery, is limited to the anterior segment of the eye, is always Gram stain and culture negative, and usually improves with steroid treatment. The primary differential diagnosis is infectious endophthalmitis. Review of the literature indicates that possible causes of TASS include intraocular solutions with inappropriate chemical composition, concentration, pH, or osmolality; preservatives; denatured ophthalmic viscosurgical devices; enzymatic detergents; bacterial endotoxin; oxidized metal deposits and residues; and factors related to intraocular lenses such as residues from polishing or sterilizing compounds. An outbreak of TASS is an environmental and toxic control issue that requires complete analysis of all medications and fluids used during surgery, as well as complete review of operating room and sterilization protocols.

Toxic anterior segment syndrome and possible association with ointment in the anterior chamber following cataract surgery

PURPOSE

To report clinical and laboratory findings of 8 cases of toxic anterior segment syndrome (TASS) related to an oily substance in the anterior chamber of patients following cataract surgery with intraocular lens (IOL) implantation.

SETTING

John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

METHODS

Eight patients had uneventful phacoemulsification by the same surgeon via clear corneal incisions with implantation of the same 3-piece silicone IOL design. Postoperative medications included antibiotic/steroid ointment and pilocarpine gel; each eye was firmly patched at the end of the procedure. On the first postoperative day, some patients presented with diffuse corneal edema, increased intraocular pressure, and an oily film-like material within the anterior chamber coating the corneal endothelium. The others presented with an oily bubble floating inside the anterior chamber, which was later seen coating the IOL. Additional surgical procedures required included penetrating keratoplasty, IOL explantation, and trabeculectomy. Two corneal buttons were analyzed histopathologically. Two explanted IOLs had gross and light microscopic analyses (as well as surface analyses of 1 of them), and 4 other explanted IOLs had gas chromatography-mass spectrometry.

RESULTS

Pathological examination of the corneas showed variable thinning of the epithelium with edema. The stroma was diffusely thickened and the endothelial cell layer was absent. Evaluation of the explanted IOLs confirmed the presence of an oily substance coating large areas of their anterior and posterior optic surfaces. Gas chromatography-mass spectrometry of the lens extracts identified a mixed chain hydrocarbon compound that was also found in the gas chromatography-mass spectrometry analyses of the ointment used postoperatively.

CONCLUSIONS

The results indicate that the ointment gained access to the eye, causing the postoperative complications described. These cases highlight the importance of appropriate wound construction and integrity, as well as the risks of tight eye patching following placement of ointment.

Fixed dilated pupil after penetrating keratoplasty for macular corneal dystrophy and keratoconus

PURPOSE

To identify predisposed eyes, risk factors, and protective measures and to evaluate methods of treatment for fixed dilated pupil after penetrating keratoplasty (PKP) for macular corneal dystrophy (MCD) and keratoconus.

DESIGN

Retrospective observational case series.

METHODS

A retrospective review was conducted of the charts of 195 patients who had PKP for MCD and of 1800 patients who had PKP for keratoconus at the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia. The review included an evaluation of the preoperative and intraoperative data and the postoperative course. In addition, clinical examinations at the last visit and photographs of the cornea, pupil, iris, and lens were analyzed.

RESULTS

Twenty-one eyes of 18 patients had fixed dilated pupil after PKP; 15 eyes of 12 patients had MCD, and six eyes of six patients had keratoconus. A rise in intraocular pressure (IOP) during the procedure was seen in five patients (23.8%). Fixed dilated pupil was documented on the first and second postoperative days and the second postoperative week in 17 (80.9%), one (4.8%), and three (14.3%) eyes, respectively. Six eyes (28.6%) of six patients had severe eye inflammation. Only one eye (4.8%) regained partial reactivity of the pupil on follow-up visits. Seven eyes (33.3%) experienced lens changes; nine eyes (42.8%) had elevated IOP on the first postoperative day, and none of the eyes had chronic glaucoma.

CONCLUSION

Inflammatory and multifactorial pathologic condition can cause fixed pupil after PKP. Atropine use, keratoconus, and high IOP are not constant findings in this syndrome. Awareness of the risk factors of fixed dilated pupil will help prevent against its occurrence.