Corneal Endothelial Damage Research Articles

Preservation of corneal endothelium after pars plana tube insertion of the Ahmed glaucoma valve

To investigate surgical outcomes after pars plana implantation of the Ahmed glaucoma valve (ppAGV). The intraocular pressure, corneal endothelial damage and post-surgical complications of 31 consecutive refractory glaucoma eyes of 26 subjects who underwent ppAGV were prospectively studied at two centers. Cell density (CD) at the central cornea decreased by 3.5 ± 15.0 and 10.2 ± 18.9% at 6 and 12 months, respectively. The CD loss at 1 year was comparable with the loss after cataract surgery alone (6.5 ± 8.5%, P = 0.441). Hexagonality (Hex) changed little, from 41.5 ± 15.6% at baseline to 41.8 ± 14.9% (P = 0.976) at 6 months and 41.6 ± 10.2% (P = 0.58) at 12 months. The coefficient of variation of the central corneal endothelium area (CV) changed from 40.7 ± 9.0% at baseline to 45.7 ± 12.6% (P = 0.078) at 6 months and 45.5 ± 11.2% (P = 0.013) at 12 months. Concomitant cataract surgery was a significant risk factor for CD loss. The probabilities of success or qualified success at 1 year were 66.1 and 83.6%, respectively. Most of the posterior segment complications, which were noted in 6 of 31 eyes (19%), were self-limiting, except for 2 eyes (6%) that developed retinal detachment as a consequence of kissing choroidal detachment. Corneal endothelial damage was minimal, and the success probability was relatively high after ppAGV in refractive glaucoma cases.

Corneal Endothelial Damage After Collagen Cross-Linking Treatment

To report a case of severe corneal endothelial damage after collagen cross-linking treatment in a 37-year-old man with progressive keratoconus with a corneal thickness of more than 400 μm. After central epithelial debridement, the left cornea was cross-linked for 25 minutes using dextran-riboflavin solution and UV-A light of 370 nm with an irradiance of 3.0 mW/cm2. One month after cross-linking treatment, the patient presented with massive corneal edema. He was treated with 1% prednisolone and carboxymethylcellulose 1% eyedrops 4 times a day for 3 months. Specular microscopy with endothelial cell counting was performed after resolution of the corneal edema 6 months after cross-linking. Despite intense treatment, a ring-shaped corneal scar remained, and uncorrected visual acuity was finger counting. Cell density after resolution was 1776 cells per square millimeter in the affected eye compared with 2978 cells per square millimeter in the untreated fellow eye. Corneal thickness is not the only factor for corneal endothelial damage after cross-linking procedure.

Corneal endothelial autocrine trophic factor VIP in a mechanism-based strategy to enhance human donor cornea preservation for transplantation

Vasoactive intestinal peptide (VIP) and ciliary neurotrophic factor (CNTF) are identified as autocrines of human corneal endothelial (CE) cells working in concert to maintain the differentiated state and promote the survival of the corneal endothelium. From VIP gene knockdown study, endogenous VIP is shown to maintain the level of the differentiation marker, the adhesion molecule N-cadherin, CE cell size, shape, and retention, in situ in the human donor corneoscleral explants. Exogenous VIP protects the corneal endothelium against the killing effect of oxidative stress, in part by upholding ATP levels in CE cells dying of oxidative stress-induced injury, allowing them to die of an apoptotic death instead of an acute necrotic one. The switch from the acute necrosis to the programmed cell death (apoptosis) may have allowed the injured CE cell to be rescued by the VIP-upregulated pathways, including those of Bcl-2 and N-cadherin, and resulted in long-term CE cell survival. The endogenous VIP in CE cells is upregulated by CNTF, which is released by CE cells surviving the oxidative stress. The CNTF receptor (CNTFRα) is expressed in CE cells in human donor corneoscleral explant and gradually becomes lost during corneal storage. VIP treatment (10−8 M, 37 °C, 30 min) prior to storage of freshly dissected human donor corneoscleral explants increases their CE cell CNTFRα level and responsiveness to CNTF in upregulating the gap junctional protein connexin-43 expression. VIP treatment of both fresh and preserved corneoscleral explants reduces CE damage in the corneoscleral explants and in the corneal buttons trephined from them. CE cell loss is a critical risk factor in corneal graft failure at any time in the life of the graft, which can be as late as 5–10 years after an initially successful transplant. A new procedure, Descemet’s stripping automated endothelial keratoplasty (DSAEK), which is superior to the traditional full thickness transplantation in many aspects, nevertheless subjects the corneal endothelium to extensive mechanical forces, resulting in even more pronounced CE cell loss than the traditional technique. Whereas it is known that cells transduce mechanical stress through N-cadherin, stimulation of the N-cadherin pathway increases the anti-apoptotic protein Bcl-2 expression. Since N-cadherin and Bcl-2 in the corneal endothelium are both upregulated by VIP, we aim to strengthen the CE sheet by VIP treatments of the corneoscleral explants for full thickness traditional corneal transplantation and pre-cut corneas for DSAEK.

Bilateral spontaneous anterior dislocation of crystalline lens in an infant

A 9-month-old boy presented with photophobia of 2-week duration in both eyes. There was no history of trauma. Ocular examination showed bilateral anterior dislocation of crystalline lenses into the anterior chamber. Examination under anaesthesia showed the dimensions of the right cornea to be 13·5 mm (horizontal) × 13·0 mm (vertical) and the left cornea to be 14·5 mm × 14·0 mm. Intraocular pressure was 12 mm Hg in each eye. Systemic examination did not show any abnormalities. His family history was unremarkable. The fundus was normal in both eyes. A diagnosis of bilateral spherophakia and megalocornea with anterior dislocation of crystalline lenses was made. The crystalline lenses were removed through a limbal incision in the right eye and lensectomy with anterior vitrectomy in the left eye. Postoperatively, the child was visually rehabilitated with aphakic glasses. Trans-scleral fixation of intraocular lens will be done after stabilisation of axial growth. Bilateral spontaneous anterior dislocation of crystalline lens is a rare condition in spherophakia, necessitating prompt diagnosis and management to avoid glaucoma and corneal endothelial cell damage. A 9-month-old boy presented with photophobia of 2-week duration in both eyes. There was no history of trauma. Ocular examination showed bilateral anterior dislocation of crystalline lenses into the anterior chamber. Examination under anaesthesia showed the dimensions of the right cornea to be 13·5 mm (horizontal) × 13·0 mm (vertical) and the left cornea to be 14·5 mm × 14·0 mm. Intraocular pressure was 12 mm Hg in each eye. Systemic examination did not show any abnormalities. His family history was unremarkable. The fundus was normal in both eyes. A diagnosis of bilateral spherophakia and megalocornea with anterior dislocation of crystalline lenses was made. The crystalline lenses were removed through a limbal incision in the right eye and lensectomy with anterior vitrectomy in the left eye. Postoperatively, the child was visually rehabilitated with aphakic glasses. Trans-scleral fixation of intraocular lens will be done after stabilisation of axial growth. Bilateral spontaneous anterior dislocation of crystalline lens is a rare condition in spherophakia, necessitating prompt diagnosis and management to avoid glaucoma and corneal endothelial cell damage.

Corneal Endothelial Autocrine VIP Enhances Its Integrity in Stored Human Donor Corneoscleral Explant

To demonstrate corneal endothelial (CE) integrity enhanced during eye banking by a brief treatment of human donor corneoscleral explant (explant) with CE autocrine trophic factor vasoactive intestinal peptide (VIP). Paired explants were used as control versus VIP (10 nM)-treated before storage in corneal storage medium (4°C). CE ciliary neurotrophic factor receptor (CNTFRα) and CNTF (0.83 nM) responsiveness in connexin 43 upregulation were monitored (Western blot analysis). CE damage in CNTF-modulated explants and corneal buttons from explants was quantified by analysis of panoramic and microscopic images of the alizarin red-stained corneal endothelium. CE cells scraped from the Descemet's membrane were counted. CE VIP receptor was demonstrated (Western blot analysis). CE cells in every VIP-treated, freshly dissected explant demonstrated higher CNTFRα levels than controls (100% vs. 142% ± 15%; P = 0.014; 7 pairs stored for 4 to 25 days). Nine days after VIP treatment of previously preserved explants, CNTF responsiveness was 174% ± 23% (P = 0.023; 4 pairs) of controls. Panoramic images of explants and corneal buttons revealed that VIP treatment reduced CE damage to 75% ± 6% (P = 0.023; 4 pairs) and 71% ± 11% (P = 0.016; 9 pairs) of controls, respectively, whereas CE damage to 39% (2 pairs) and 23% ± 4% (P < 0.001; 7 pairs), respectively, was revealed in microscopic images. Twenty-one days after VIP treatment of previously preserved explants, CE cell retention was 206% ± 38% (P = 0.008; 14 pairs) of the control. CE cells from human donor corneas expressed VIP receptor VPAC1 (not VPAC2). CE integrity during eye banking was enhanced by a brief treatment of the explant with the CE autocrine VIP.

Cytotoxicity of Voriconazole on Cultured Human Corneal Endothelial Cells

The purpose of the present study was to evaluate the toxicity of voriconazole on cultured human corneal endothelial cells (HCECs). HCECs were cultured and exposed to various concentrations of voriconazole (5.0 to 1,000 μg/ml). Cell viability was measured using a Cell Counting Kit-8 (CCK-8) and live/dead viability/cytotoxicity assays. Cell damage was assessed using phase-contrast microscopy after 24 h of exposure to voriconazole. To analyze the effect of voriconazole on the intercellular barrier, immunolocalization of zonula occludens 1 (ZO1) was performed. A flow cytometric assay was performed to evaluate the apoptotic and necrotic effects of voriconazole on HCECs. Cytotoxicity tests demonstrated the dose-dependent toxic effect of voriconazole on HCECs. Voriconazole concentrations of ≥100 μg/ml led to a significant reduction in cell viability. The morphological characteristics of HCECs also changed in a dose-dependent manner. Increasing concentrations of voriconazole resulted in fading staining for ZO1. Higher concentrations of voriconazole resulted in an increased number of propidium iodide (PI)-positive cells, indicating activation of the proapoptotic pathway. In conclusion, voriconazole may have a dose-dependent toxic effect on cultured HCECs. The results of this study suggest that although voriconazole concentrations of up to 50 μg/ml do not decrease cell viability, intracameral voriconazole concentrations of ≥100 μg/ml may increase the risk of corneal endothelial damage.

Cataract surgery in eyes with low corneal endothelial cell density

To compare corneal endothelial damage after cataract surgery in eyes with low endothelial cell density (ECD) and eyes with normal ECD. Hayashi Eye Hospital, Fukuoka, Japan. Case-control study. Cataract surgery was performed in eyes with a low ECD (500 to 1000 cells/mm(2)) (low-density group) and control eyes with a normal ECD. The ECD and central corneal thickness (CCT) were measured preoperatively and 1 and 3 months postoperatively, and the percentage cell loss and increase in CCT were compared. The low-density group and control group each comprised 50 eyes. In the low-density group, 39 eyes had nonprogressive endothelial pathology and 11 had Fuchs dystrophy. The mean ECD was significantly less and the CCT significantly greater in the low-density group than in the control group throughout the follow-up (P ≤.0066). However, no significant difference in the percentage of cell loss was found between groups at 1 or 3 months (5.1%, low-density group; 4.2%, control group) (P ≥.1477). The percentage increase in CCT was significantly greater in the low-density group than in the control group at 1 month (P<.0001), although there was no significant difference at 3 months (0.4% and -0.4%, respectively) (P=.2172). Corneal endothelial damage after cataract surgery in eyes with low ECD was slight and comparable to that in healthy eyes, which suggests that cataract surgery alone (without corneal transplantation) should be performed first.

Lesão escleral durante o agulhamento com mitomicina C: relato de caso

A 70-year-old female patient underwent cataract and glaucoma surgery on her left eye in 1996. Eleven years later, we performed two bleb needling revisions with adjunctive mytomicin-C, in order to decrease an uncontrolled intraocular pressure of 32 mmHg. After the second needling, she developed severe overfiltration, with flat anterior chamber, choroidal effusion, and impending corneal decompensation. Conservative treatment with cycloplegic and corticosteroid eye drops, acetazolamide and therapeutic contact lenses was unsuccessfully tried. Anterior chamber reformation was successively tried with air, 4% ophthalmic viscosurgical device and 1% sodium hyaluronate, with only temporary results. Compressive sutures above the overfiltering bleb were applied, unsuccessfully. In order to avoid additional corneal endothelium damage, a surgical bleb revision was performed and revealed a large area of ciliary body and choroidal exposure under the conjunctiva. It was covered by a donor scleral patch graft providing successful resolution. Nevertheless, we had to reintroduce hypotensive eyedrops. While bleb needling is a relatively safe and effective procedure, ophthalmologists should be aware of the possibility of potentially serious complications, such as in this case report.

New surgical technique for correcting tube-iris touch following glaucoma drainage implant surgery

Glaucoma drainage implant surgery may be associated with a number of potential complications including tube malpositioning. This malpositioning may have serious sequelae such as corneal endothelial damage, chronic iritis, cataract formation or tube occlusion. Traditional management of tube malpositioning involves major surgical re-dissection and reinsertion of the tube. Alternatively, shortening of the tube within the anterior chamber can, in some circumstances, relieve tube contact with the endothelium or iris. However, these procedures are associated with important risks. We describe a new minimally invasive surgical technique for correcting posterior tube malpositioning that avoids the need to shorten the tube or re-dissect the conjunctiva. This technique is straightforward to perform and has successfully maintained proper drainage device tube position during more than 1 year of follow up.

Complications of Corneal Collagen Cross-Linking

Cross-linking of corneal collagen (CXL) is a promising approach for the treatment of keratoconus and secondary ectasia. Several long-term and short-term complications of CXL have been studied and documented. The possibility of a secondary infection after the procedure exists because the patient is subjected to epithelial debridement and the application of a soft contact lens. Formation of temporary corneal haze, permanent scars, endothelial damage, treatment failure, sterile infiltrates, and herpes reactivation are the other reported complications of this procedure. Cross-linking is a low-invasive procedure with low complication and failure rate but it may have direct or primary complications due to incorrect technique application or incorrect patient's inclusion and indirect or secondary complications related to therapeutic soft contact lens, patient's poor hygiene, and undiagnosed concomitant ocular surface diseases.

This issue of Acta

This issue of Acta

Evaluation of phacoemulsification‐induced oxidative stress and damage of cultured human corneal endothelial cells in different solutions using redox fluorometry microscopy

To describe the basic concept of redox fluorometry microscopy and investigate its efficacy in evaluating the state of cultured human corneal endothelial cells in different solutions when ultrasonic energy was applied in vitro. Human corneal endothelial cells from human donor tissue not suitable for transplantation were cultured. A phacoemulsification probe with a 30° round, 1.1-mm TurboSonics(®) ABS™ Tip (Alcon, Fort Worth, Texas) was introduced into culture dishes filled with balanced salt solution (BSS) and BSS plus (Alcon, Fort Worth, Texas). Cellular autofluorescence images were obtained using a Zeiss inverted microscope. The redox fluorometric ratio, which can be related to cellular metabolism, mitochondrial distribution patterns, which can shift in reaction to environmental changes, and cell size were analysed with a software program. Human corneal endothelial cells exposed to increasing phacoemulsification times and ultrasonic energy displayed dose-dependent decreases in redox ratios. At a lower ultrasonic power and time, BSS plus showed significantly less change in redox ratio than BSS and control (p < 0.05, Mann-Whitney test). As ultrasonic power and time increased, BSS plus had no more significance. Redox fluorometry, with further technological improvement, might be an interesting and potentially useful tool for evaluation of phacoemulsification-induced corneal endothelial damage and screening of protective agents in vitro.

Expression of aquaporin-1 in rabbit corneal endothelium after chronic ocular hypertension

目的 观察慢性高眼压状态下水通道蛋白-1(AQP-1)在家兔角膜内皮细胞上的表达变化.方法 30只成年家兔随机分为对照组,2、3、4、5周组.非对照组实验兔左眼前房内注入质量分数0.3%卡波姆和质量分数0.025%地塞米松的复方卡波姆溶液0.2 mL,眼压达22 mmHg以上者为制作家兔慢性高眼压模型成功;对照组左眼用同样方法注入平衡盐液0.2 mL.建模后每日测量眼压1次,裂隙灯下观察实验眼结膜、角膜及虹膜组织的反应.注药后2、3、4、5周分别处死各组实验兔并制作角膜标本,应用免疫组织化学法检测角膜内皮中AQP-1蛋白的表达,应用半定量逆转录聚合酶链反应(RT-PCR)法检测家兔角膜内皮中AQP-1 mRNA在角膜内皮中的表达.所有动物的饲养及处死遵循NIH的 .结果 建模后实验动物的眼压呈缓慢升高的趋势,3周时达到最高,之后眼压逐渐下降,5周时眼压接近正常.在建模后18～24 d,角膜水肿和虹膜组织炎症反应最严重.AQP-1在正常和高眼压家兔的角膜内皮均有表达,各组间AQP-1的吸光度(A)值差异有统计学意义(F=3.650,P=0.018),AQP-1 mRNA在角膜内皮中的表达量亦随之出现先升高后降低的趋势,各组的总体比较差异有统计学意义(F=4.140,P=0.000).AQP-1在角膜内皮中的表达量在造模后2、3、4、5周时与对照组间差异均有统计学意义(P＜0.05).结论 AQP-1可能在家兔角膜内皮损伤修复过程中起到重要作用。

Protection of Thymosin Beta-4 on Corneal Endothelial Cells from UVB-Induced Apoptosis

Cornea absorbs most of daily ultraviolet (UV) light. An excess of UV damages results in not only keratopathy and cataract but also maculopathy. It has been reported that thymosin beta-4 (Tbeta4) promotes wound healing, decreases inflammatory response and prevents apoptosis of corneal epithelial cells. However, it is not clear whether Tbeta4 protects UVB-induced corneal injury, particularly in corneal endothelial cells because of its non-proliferation in nature. The purpose of this study is to compare the protective effects of Tbeta4 on bovine corneal endothelial (BCE) cells from low- and high-dose UVB damage. In this study, 1 microg/ml of Tbeta4 was added to BCE cells 2 h before low (12.5 mj/cm2) or high dosage (100 mj/cm2) UVB exposure. Using a fluorogenic substrate cleavage assay, we found that Tbeta4 diminished the reactive oxygen species level in BCE cells elicited by UVB. However, the protection of viability by Tbeta4 could only be detected under low-dose UVB exposure. Moreover, both caspase-9 activity and annexin V/propidium iodine staining demonstrated that Tbeta4 only protected BCE cells from low-dose UVB-induced apoptosis but not high-dose UVB-induced necrosis. Together, Tbeta4 protected corneal endothelial cells from UVB-induced oxidative stress and apoptosis after low-dose UVB exposure. The results support further investigation towards topical use or anterior chamber injection of this small hydrophilic peptide in treating and preventing UVB-induced corneal endothelial damage.

Absence of corneal endothelium injury in non‐human primates treated with and without ophthalmologic drugs and exposed to 2.8 GHz pulsed microwaves

Microwave-induced corneal endothelial damage was reported to have a low threshold (2.6 W/kg), and vasoactive ophthalmologic medications lowered the threshold by a factor of 10-0.26 W/kg. In an attempt to confirm these observations, four adult male Rhesus monkeys (Macaca mulatta) under propofol anesthesia were exposed to pulsed microwaves in the far field of a 2.8 GHz signal (1.43 +/- 0.06 micros pulse width, 34 Hz pulse repetition frequency, 13.0 mW/cm(2) spatial and temporal average, and 464 W/cm(2) spatial and temporal peak (291 W/cm(2) square wave equivalent) power densities). Corneal-specific absorption rate was 5.07 W/kg (0.39 W/kg/mW/cm(2)). The exposure resulted in a 1.0-1.2 degrees C increase in eyelid temperature. In Experiment I, exposures were 4 h/day, 3 days/week for 3 weeks (nine exposures and 36 h total). In Experiment II, these subjects were pretreated with 0.5% Timolol maleate and 0.005% Xalatan(R) followed by 3 or 7 4-h pulsed microwave exposures. Under ketamine-xylazine anesthesia, a non-contact specular microscope was used to obtain corneal endothelium images, corneal endothelial cell density, and pachymetry at the center and four peripheral areas of the cornea. Ophthalmologic measurements were done before and 7, 30, 90, and 180 days after exposures. Pulsed microwave exposure did not cause alterations in corneal endothelial cell density and corneal thickness with or without ophthalmologic drugs. Therefore, previously reported changes in the cornea exposed to pulsed microwaves were not confirmed at exposure levels that are more than an order of magnitude higher.

Cytotoxicity of Topical Medications Used for Infection and Inflammation Control after Cataract Surgery in Cultured Corneal Endothelial Cells

Postoperative vision-threatening corneal edema sometimes occurs after eye surgery, and corneal endothelial damage may be caused or exacerbated by drug toxicity. A range of commercially available antibiotic and anti-inflammatory ophthalmic solutions used postoperatively, namely levofloxacin, moxifloxacin, gatifloxacin, cefmenoxime, diclofenac, bromfenac, pranoprofen, betamethasone, and fluoromethorone, were assessed by using human corneal endothelial cells (HCECs). Propylparaoxybenzoate and methylparaoxybenzoate were also examined. Cell survival after 48 h exposure to the drugs was evaluated using the WST assay. Cefmenoxime and betamethasone were the least toxic antibiotic and anti-inflammatory drug, respectively. Cell survival was concentration dependent and increased markedly to ≥ 80% with dilutions of 100-fold or more. Two preservatives seemed to cause minimal cytotoxicity among those tested. Antibiotic cytotoxicity to HCEC was ranked as cefmenoxime < levofloxacin = gatifloxacin < moxifloxacin, while the toxicity of anti-inflammatory drugs was dependent on benzalkonium chloride and polysorbate. These drugs are unlikely to cause HCEC damage at the concentrations used under the usual conditions. Preservatives are essential ingredients in ophthalmic solutions to control postoperative infection and inflammation and we should be aware of their toxicity as well as efficacy.

A Case of Corneal Endothelial Damage by 5-Fluorouracil Inflow Into Anterior Chamber After Subconjunctival Injection

Purpose: To present a case of corneal endothelial damage caused by inflow of 5-FU after subconjunctival 5-FU injection in a patient undergoing trabeculectomy. Case Summary: A 65-year-old female patient diagnosed with chronic angle-closure glaucoma underwent trabeculectomy using mitomycin C. Three weeks after the surgery, her intraocular pressure (IOP) elevated, and the follicles had disappeared by trabeculectomy. Subsequently, subconjunctival 5-FU injection was performed. Following the fourth injection, visual acuity abruptly decreased, and corneal edema was observed. Upon presumption of inflow of 5-FU into the anterior chamber, anterior chamber irrigation was performed within 40 minutes. On postoperative day 1, visual acuity decreased from 0.8 to counting fingers, and diffuse corneal edema and anterior capsular opacity of the lens were noted. Three months after the irrigation, visual acuity improved to 0.8. Corneal edema and capsular opacity also improved, however the density of the corneal endothelial count decreased. Conclusions: Inflow of 5-FU into the anterior chamber can cause corneal and lenticular toxicity. Anterior chamber irrigation is considered necessary to prevent 5-FU toxicity.

Toxicity evaluation of biodegradable and thermosensitive PEG‐PCL‐PEG hydrogel as a potential in situ sustained ophthalmic drug delivery system

In this work, a biodegradable poly(ethylene glycol)-poly(epsilon-caprolactone)-poly (ethylene glycol) (PEG-PCL-PEG, PECE) triblock copolymer was successfully synthesized, which was flowing sol at low temperature and turned to nonflowing gel at body temperature. The toxicity evaluation of PECE hydrogel as a potential in situ sustained opthalmic drug delivery system was performed, including the biodegradability of PECE hydrogel in the eye, its effect on cultured human lens epithelia, intraocular pressure, and ocular tissues. The results indicated that the prepared PECE hydrogel was biocompatible and biodegradable despite of temporary elevated intraocular pressure and slight corneal endothelial damage at specific concentration. Therefore, PECE hydrogel may be a safe candidate for sustained ophthalmic drug delivery system.

Safety of Intracameral Injection of Gatifloxacin, Levofloxacin on Corneal Endothelial Structure and Viability

To investigate the safety of intracameral injection of gatifloxacin, levofloxacin in a rabbit model as prophylaxis against endophthalmitis. Twenty-four eyes of New Zealand white rabbits were randomly divided into 3 treatment groups: levofloxacin, gatifloxacin, and balanced salt solution (BSS) control groups. After 100 microL of each was injected into the anterior chamber, endothelial toxicity was evaluated by measuring the central corneal thicknesses and the clinical toxicity scores using a slit-lamp at post-procedure days 3 and 7. The percent of dead cells was determined by vital staining with alizarin red and trypan blue at 7 days after injection. Finally, in each group, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed for the evaluation of structural integrity. The toxicity scores were increased at post-procedure days 3 and 7, but the difference among the groups was not statistically significant (P = 0.661, 0.216, respectively). With regard to baseline corneal thickness, only the levofloxacin group exhibited a significant increase from baseline (P = 0.028), whereas the other treatment groups showed no difference from baseline (P = 0.128 in gatifloxacin, 0.161 in BSS group). The mean corneal endothelial damage was 0.81 +/- 0.31% in the levofloxacin group, 0.56 +/- 0.47% in the gatifloxacin group, and 0.53 +/- 0.52% in the BSS group, with no statistically significant difference noted among the groups (P = 0.582). SEM revealed a well-preserved hexagonal endothelial cell mosaic and normal microvilli on the endothelial cell surface in the gatifloxacin and control groups. However, the levofloxacin group showed slightly disintegrated cellular borders. TEM revealed that each group maintained normal intracellular organization, whereas the levofloxacin group exhibited slightly flat cell configuration with irregular folds on the apical cell surface. Intracameral injection of gatifloxacin and levofloxacin was nontoxic in terms of clinical toxicity score, corneal thickness, and viability. However, there were changes on electron microscopy in the levofloxacin group, which may indicate microstructural damage to corneal endothelial cells.

Viscoanaesthesia in cataract surgery: a prospective, randomized clinical trial

We aimed to compare viscoanaesthesia (VisThesia) with intracameral lidocaine in cataract surgery carried out under topical anaesthesia. In this prospective study 98 patients were randomly assigned to receive VisThesia (group 1, n = 49) or 0.5 cc of 1% unpreserved lidocaine (group 2, n = 49). All surgery was carried out by one surgeon using clear corneal technique. Pachymetry, the status of the cornea and anterior chamber, and intraocular pressure (IOP) were checked pre- and postoperatively. Mean pain scores were 0.12 (maximum: 3) in group 1 and 0.37 in group 2; the difference between the groups was not statistically significant (95% confidence interval [CI] 0.003-0.487; p = 0.05). A total of 48 patients in group 1 (98%) and 49 in group 2 (100%) reported no discomfort or only mild discomfort. No significant differences in flare and cells in the anterior chamber or IOP were found between the two study groups. There was a significantly greater frequency of corneal oedema in group 1 (p = 0.001). Postoperative central corneal thickness values were also significantly higher in group 1 (95% CI 11.64-57.24; p = 0.003). Results suggest that viscoanaesthesia provides a level of comfort during cataract surgery under topical anaesthesia similar to that facilitated by intracameral lidocaine. However, patients who are given viscoanaesthesia may have increased risk for postoperative corneal oedema.