Prospective, Randomized Clinical Trial of Povidone-Iodine 1.25% Solution Versus Topical Antibiotics for Treatment of Bacterial Keratitis.

PURPOSE: To compare povidone-iodine 1.25% ophthalmic solution with topical antibiotics for treatment of bacterial keratitis in areas of the world where use of effective topical antibiotics may not be an option. STUDY DESIGN: Randomized, controlled, investigator-masked clinical trial. METHODS: We randomized 172 individuals with bacterial keratitis to topical treatment with povidone-iodine or antibiotics (neomycin-polymyxin B-gramicidin in the Philippines; ciprofloxacin 0.3% in India). Using survival analysis, we compared intervals from start of treatment to "presumed cure" (primary outcome measure, defined as a closed epithelial defect without associated inflammatory signs) and to "recovering" (residual epithelial defect <1 mm2 with only minimal inflammation). RESULTS: Median interval to presumed cure in the Philippines was 7 days for povidone-iodine and 7 days for neomycin-polymyxin B-gramicidin (95% confidence interval [CI] for difference in median interval, -9.5 to 0.7 days) and in India was 12 days for povidone-iodine and 17 days for ciprofloxacin (95% CI, -35.2 to 3.2 days). Hazard ratio (HR) for presumed cure among those treated with povidone-iodine (vs antibiotics) was 1.46 in the Philippines (95% CI, 0.90-2.36; P = .13) and 1.70 in India (95% CI, 0.73-3.94; P = .22). Comparisons of intervals to recovering and HR for recovering also revealed no significant differences between treatment groups in either country. CONCLUSIONS: There is no significant difference between the effect of topical povidone-iodine 1.25% and topical antibiotics commonly available in the developing world for treatment of bacterial keratitis. Povidone-iodine 1.25%, which is widely available and inexpensive, can be considered for treatment of bacterial keratitis when antibiotic treatment is not practical.

Topical corticosteroids as adjunctive therapy for bacterial keratitis.

BACKGROUND: Bacterial keratitis is a serious ocular infectious disease that can lead to severe visual disability. Risk factors for bacterial corneal infection include contact lens wear, ocular surface disease, corneal trauma, and previous ocular or eyelid surgery. Topical antibiotics constitute the mainstay of treatment in cases of bacterial keratitis, whereas the use of topical corticosteroids as an adjunctive therapy to antibiotics remains controversial. Topical corticosteroids are usually used to control inflammation using the smallest amount of the drug. Their use requires optimal timing, concomitant antibiotics, and careful follow-up. OBJECTIVES: The objective of the review was to assess the effectiveness and safety of corticosteroids as adjunctive therapy for bacterial keratitis. Secondary objectives included evaluation of health economic outcomes and quality of life outcomes. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2014), EMBASE (January 1980 to July 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to July 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 14 July 2014. We also searched the Science Citation Index to identify additional studies that had cited the only trial included in the original version of this review, reference lists of included trials, earlier reviews, and the American Academy of Ophthalmology guidelines. We also contacted experts to identify any unpublished and ongoing randomized trials. SELECTION CRITERIA: We included randomized controlled trials (RCTs) that had evaluated adjunctive therapy with topical corticosteroids in people with bacterial keratitis who were being treated with antibiotics. DATA COLLECTION AND ANALYSIS: We used the standard methodological procedures expected by The Cochrane Collaboration. MAIN RESULTS: We found four RCTs that met the inclusion criteria of this review. The total number of included participants was 611 (612 eyes), ranging from 30 to 500 participants per trial. One trial was included in the previous version of the review, and we identified three additional trials through the updated searches in July 2014. One of the three smaller trials was a pilot study of the largest study: the Steroids for Corneal Ulcers Trial (SCUT). All trials compared the treatment of bacterial keratitis with topical corticosteroid and without topical corticosteroid and had follow-up periods ranging from two months to one year. These trials were conducted in the USA, Canada, India, and South Africa.All trials reported data on visual acuity ranging from three weeks to one year, and none of them found any important difference between the corticosteroid group and the control group. The pilot study of the SCUT reported that time to re-epithelialization in the steroid group was 53% slower than the placebo group after adjusting for baseline epithelial defect size (hazard ratio (HR) 0.47; 95% confidence interval (CI) 0.23 to 0.94). However, the SCUT did not find any important difference in time to re-epithelialization (HR 0.92; 95% CI 0.76 to 1.11). For adverse events, none of the three small trials found any important difference between the two treatment groups. The investigators of the largest trial reported that more patients in the control group developed intraocular pressure (IOP) elevation (risk ratio (RR) 0.20; 95% CI 0.04 to 0.90). One trial reported quality of life and concluded that there was no difference between the two groups (data not available). We did not find any reports regarding economic outcomes.Although the four trials were generally of good methodological design, all trials had considerable losses to follow-up (10% or more) in the final analyses. Further, three of the four trials were underpowered to detect treatment effect differences between groups and inconsistency in outcome measurements precluded meta-analyses for most outcomes relevant to this review. AUTHORS' CONCLUSIONS: There is inadequate evidence as to the effectiveness and safety of adjunctive topical corticosteroids compared with no topical corticosteroids in improving visual acuity, infiltrate/scar size, or adverse events among participants with bacterial keratitis. Current evidence does not support a strong effect of corticosteroid, but may be due to insufficient power to detect a treatment effect.

Collagen cross-linking and corneal infections.

PURPOSE OF REVIEW: This review presents current data regarding the use of collagen cross-linking in the management of corneal infections. Infectious keratitis can lead to blindness without proper antimicrobial therapy. The disease can still progress and lead to corneal melt despite early detection and management. The aggressive nature of corneal pathogens and the threat of antibiotic-resistance make it necessary to develop newer ways of managing this rapidly progressive condition. RECENT FINDINGS: Collagen cross-linking is a noninvasive ocular surface procedure that is used to effectively strengthen the cornea. This technique presents as a novel treatment option to halt the progression of keratoconus and ectasia. More recently, however, several articles have demonstrated the effectiveness of cross-linking in treating infectious keratitis via direct microbiologic cure and possibly, inhibition of corneal enzymatic degradation by common pathogenic organisms. SUMMARY: Current literature reveals that corneal collagen cross-linking holds promise in treating infectious keratitis. However, larger-scale, randomized, controlled trials comparing cross-linking to standard antibiotic therapy are still warranted to support these findings.

Demonstration by redox fluorometry that sulforaphane protects retinal pigment epithelial cells against oxidative stress.

PURPOSE: To quantify the effects of oxidant challenge on the redox state of adult human retinal pigment epithelial cells using microscopic autofluorescence spectroscopy and to determine whether treatment with the isothiocyanate sulforaphane protects these cells against oxidative stress. METHODS: Oxidative stress was evoked in ARPE-19 cells by H2O2 and tert-butyl hydroperoxide. Reduced nicotinamide nucleotides NAD(P)H were assessed by excitation at 366 nm with measurement of fluorescence at 450 nm. Oxidized flavoproteins were assessed by excitation at 460 nm with measurement of fluorescence at 540 nm. The ratio of these measurements served as the index of cellular redox status. RESULTS: Redox ratio and cell viability decreased in a dose-dependent manner after oxidant exposure. ARPE-19 cells treated with sulforaphane maintained significantly higher redox ratio and cell viability. The ratio for sulforaphane-treated cells after exposure to 0.64 mM H2O2 was 2.64 +/- 0.19 compared with 1.77 +/- 0.16 in untreated cells (P = 0.001). At 1.2 mM H2O2, the redox ratio of sulforaphane-treated cells was 2.30 +/- 0.18 compared with 1.76 +/- 0.13 in untreated cells (P = 0.02). Similar results were observed after insult with tert-butyl hydroperoxide. CONCLUSIONS: Redox fluorometry provides quantitative information on the redox status of living cells. Sulforaphane protects ARPE-19 cells from oxidative injury by induction of antioxidant phase 2 genes. The findings in this study describe a useful method for assessing antioxidant effects in live cells and support phase 2 gene induction as a potential treatment strategy for macular degeneration and diseases in which oxidative injury plays a causative role.

Microkeratome versus femtosecond laser predissection of corneal grafts for anterior and posterior lamellar keratoplasty.

PURPOSE: To compare 2 different techniques for predissection of human anterior and posterior lamellar corneal grafts for eye bank storage. METHODS: A mechanical microkeratome (group 1, N = 5) and a femtosecond laser (group 2, N = 5) were used to dissect intended 350-microm-deep lamellar planes in deepithelialized donor corneas mounted on an artificial anterior chamber. These corneas were replaced in Optisol GS at 4 degrees C postoperatively and examined 2 days later to simulate a clinical scenario. Ultrasonic pachymetry of corneal lamellar sections was measured before and after separation of the lamellar grafts. Group 1 sections were separated by the mechanical microkeratome, whereas group 2 sections were manually separated 2 days after laser dissection. Endothelial cell viability was evaluated in posterior grafts. RESULTS: Total corneal thicknesses immediately before dissection were 559 +/- 61 (group 1) and 578 +/- 79 microm (group 2; P = 0.46). Immediate postdissection anterior and posterior graft thicknesses were 361 +/- 68 and 203 +/- 74 microm (group 1), respectively. Achieved anterior and posterior graft thicknesses 2 days later were 282 +/- 44 and 413 +/- 35 microm (group 1) and 324 +/- 112 and 397 +/- 51 microm (group 2), respectively. Percentage of devitalized endothelial cells were 3.4% +/- 1.6% (group 1) and 1.6% +/- 1.2% (group 2; P = 0.35). CONCLUSIONS: Centralized predissection by both techniques, cold storage, and shipping by airmail results in viable grafts without significant endothelial cell loss 2 days later.

Microkeratome preparation of lamellar corneal grafts.

PURPOSE: To evaluate the thickness and viability of microkeratome-prepared lamellar corneal grafts in cold storage. METHODS: Ten human corneas were sectioned with a mechanical microkeratome with a 350-microm depth head and stored in Optisol GS at 4 degrees C for 2 days to simulate an eye bank scenario. Central corneal thickness before and after mechanical microkeratome sectioning was measured by ultrasonic pachymetry. Endothelial cell viability was evaluated by trypan blue and alizarin red staining. RESULTS: Total corneal thickness immediately before microkeratome dissection was 562 +/- 51 microm. Anterior and posterior graft thicknesses were 296 +/- 111 microm and 270 +/- 74 microm, respectively, immediately after dissection, and 282 +/- 38 microm and 429 +/- 31 microm, respectively, 2 days after storage. There was significant swelling in the posterior (P=0.005) but not the anterior grafts (P=0.386). The percentage of devitalized endothelial cells was 3.0% +/- 1.2%. CONCLUSIONS: Corneal lamellar grafts may possibly be precut in a centralized facility and stored cold before further distribution.

Use of topical human amniotic fluid in the treatment of acute ocular alkali injuries in mice.

PURPOSE: To evaluate the efficacy of topical human amniotic fluid (HAF) in the treatment of ocular acute alkali burns in mice. DESIGN: Experimental study. METHODS: A chemical burn with 2 microl of sodium hydroxide 0.15 mol/l was created in one eye of 30 mice. The animals were divided into gender- and age-matched groups according to the topical treatment that was administered: group 1 was treated with preterm HAF (n = 10 mice); group 2 was treated with term HAF (n = 10 mice), and group 3 was treated with saline solution (n = 10 mice). Treatment consisted of one drop that was applied to the burned eye five times per day (week one), and three times per day (week two). The epithelial defect was photographed and measured on days two and four. Ocular burn damage was assessed at days two, seven, and 14 after a pre-established classification. On day 14, both eyes of each mouse were enucleated and assessed histopathologically. RESULTS: Median epithelial defect (interquartile range [IQR], 25th, 75th percentile) at day four was 9.93% (IQR, 8.57, 11.27) for group 1, 7.30% (IQR, 5.96, 8.97) for group 2, and 18.92% (IQR, 11.71, 27.64) for group 3 (P < .0076). The overall change (difference in slope) in ocular burn score between days 2 and 14 was -0.127 (P = .009) in group 1 vs 3, -0.134 (P = .012) in group 2 vs 3, and 0.007 (P = .88) in group 1 vs 2. On histologic examination saline solution-treated corneas had more inflammatory cells and blood vessels than HAF-treated corneas. CONCLUSION: Topical preterm/term HAF was an effective topical therapy for limiting the damage after acute alkali burns of the eye in this animal model.

Modified microkeratome-assisted posterior lamellar keratoplasty using a tissue adhesive.

OBJECTIVE: To compare graft stability and astigmatic change using suture vs tissue adhesive in an experimental model of microkeratome-assisted posterior lamellar keratoplasty. METHODS: A 300-microm-thick partial flap keratectomy was performed in human donor corneoscleral rims using an artificial anterior chamber and a manual microkeratome. The flap stopped at the left central opening border, providing a wide hinge to add stability. After flap reflection, a 6.25-mm trephination was performed to obtain a disc of posterior stroma, Descemet membrane, and endothelium. The disc was positioned in a sutureless fashion, and the flap secured with either 5 interrupted sutures or a chondroitin-sulfate-aldehyde-based adhesive. Increasing intrachamber pressures were created to detect graft stability. Videokeratographic data were recorded to evaluate astigmatic change. RESULTS: The mean (SD) astigmatic change was 3.08 (0.84) diopters (D) in the sutured group and 1.13 (0.55) D in the glued group (P = .008). Mean (SD) resisted pressures were 95.68 (27.38) mm Hg and 82.45 (18.40) mm Hg in the sutured and glued groups, respectively (P = .97). CONCLUSION: This modified technique of microkeratome-assisted posterior lamellar keratoplasty showed excellent graft stability in both groups. Flaps sealed with the novel tissue adhesive had reduced astigmatic changes in our experimental model. CLINICAL RELEVANCE: Sutureless microkeratome-assisted posterior lamellar keratoplasty using tissue adhesive may become a new alternative in the surgical treatment of corneal endothelial disorders.

Metabolic changes in mesenchymal stem cells in osteogenic medium measured by autofluorescence spectroscopy.

The purpose of this study was to measure metabolic changes in mesenchymal stem cells (MSCs) placed in osteogenic medium by autofluorescence spectroscopy. MSCs were plated in stem cell-supporting or osteogenic medium and imaged. Shift from the basic growth environment to the inductive osteogenic environment was confirmed by reverse transcription-polymerase chain reaction. Reduced pyridine nucleotides were detected by exciting near 366 nm and measuring fluorescence at 450 nm, and oxidized flavoproteins were detected by exciting at 460 nm and measuring fluorescence at 540 nm. The ratio of these fluorescence measurements, reduction-oxidation (redox) fluorometry, is a noninvasive measure of the cellular metabolic state. The detected pyridine nucleotide to flavoprotein ratio decreased upon transitioning from the stem cell to the differentiated state, as well as with increasing cell density and cell-cell contact. MSC metabolism increased upon placement in differentiating medium and with increasing cell density and contact. Redox fluorometry is a feasible, noninvasive technique for distinguishing MSCs from further differentiated cells.

Botulinum toxin B-induced mouse model of keratoconjunctivitis sicca.

PURPOSE: To develop a mouse model of human chronic dry eye (keratoconjunctivitis sicca [KCS]). METHODS: Under direct visualization with an operating microscope, CBA/J mice received a transconjunctival injection of saline or 1.25, 5, or 20 milliunits (mU) of botulinum toxin B (BTX-B) into the lacrimal gland. The mice were either left unstressed or were subjected to an air blower for 5 h/d, 5 d/wk in fixed temperature and humidity conditions. Tear production and corneal fluorescein staining were evaluated in all groups before injection and at several time points after. Tear production was measured with phenol red-impregnated cotton threads. Corneal fluorescein staining was photographed under cobalt blue light with a digital camera fitted with a macro lens. RESULTS: BTX-B-injected mice displayed significantly decreased tear production until the 4-week time point. Throughout all time points, the addition of environmental blower stress did not appear to alter tear production significantly. Linear regression models, used to evaluate the effects of various doses of BTX-B on tear production, showed that doses higher than 1.25 mU did not provide significantly different outcomes. After 3 days, saline-injected mice showed no corneal staining, whereas BTX-B-injected mice displayed various amounts of staining. At the early time point (day 3), there did not appear to be an additional effect of the blower on corneal fluorescein staining. However, at 1, 2, and 4 weeks, the blower stress appeared to increase the amount of corneal fluorescein staining at each BTX-B dose, although not significantly. Furthermore, at 8 to 10 weeks, in the BTX B-injected groups, corneas had persistent staining, even though tear production had already returned to normal levels. Histopathologic analyses revealed no inflammatory cell infiltration of the stroma or acini of the lacrimal glands and conjunctivae of both saline-injected and BTX-B-injected animals. CONCLUSIONS: Intralacrimal gland injection of BTX-B resulted in persistent corneal fluorescein staining within 3 days, and a significant decrease in aqueous tear production that persisted for 1 month. Intralacrimal gland injection of BTX-B suppressed lacrimation, thereby establishing a dry eye state. This animal model could be a useful tool for investigating the pathogenesis of the chronic condition KCS in humans.

Inflow of ocular surface fluid into the anterior chamber after phacoemulsification through sutureless corneal cataract wounds.

PURPOSE: To report inflow of extraocular fluid after phacoemulsification with use of sutureless corneal incisions. DESIGN: Interventional case series. METHODS: setting: Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland. patients: Eight patients (three women), aged 58 to 91 years, showing minimal bleeding from the limbal capillary bed during phacoemulsification. intervention: Surgery was performed through a 2.8-mm limbal incision. External pressure simulating patient manipulation was applied before and after wound hydrosealing with an irrigation cannula. main outcome measures: Inflow of blood-tinged tear fluid into the anterior chamber through the wound was monitored by using digital video. RESULTS: Inflow of extraocular fluid was observed in all eyes when the cannula was released, even after wound hydrosealing. Two patients showed spontaneous fluid inflow. CONCLUSIONS: Tested sutureless corneal incisions allow inflow of extraocular fluid into the anterior chamber after phacoemulsification. This may permit intraocular contamination leading to endophthalmitis.

Noninvasive mitochondrial imaging in live cell culture.

The observed distribution of mitochondria in a cell can vary with environmental influence, degree of differentiation and disease. Differences in the distribution of mitochondrial autofluorescence may be used to distinguish these different cellular states.

A modified chondroitin sulfate aldehyde adhesive for sealing corneal incisions.

PURPOSE: To compare a modified chondroitin sulfate aldehyde adhesive with standard sutures for sealing corneal incisions. METHODS: A keratome knife was used to create non-self-sealing, uniplanar, 3-mm, clear corneal incisions in enucleated rabbit eyes (n = 18). The wounds were sealed with either a chondroitin sulfate-aldehyde adhesive (n = 8), three 10-0 nylon sutures (n = 5), or one 10-0 nylon suture (n = 5). Wound stability was tested by filling the globes with balanced salt solution through an anterior chamber port and slowly increasing the IOP. The pressure changes were monitored with a digital manometer connected to the anterior chamber, and leak pressure was recorded for each eye. Confocal microscopy was performed on the glued eyes, to document the glue distribution along the wound. RESULTS: The mean leak pressures in the single-suture and three-suture subgroups were 26.4 +/- 6.0 and 44.3 +/- 8.2 mm Hg (SD), respectively. The maximum IOP achieved in eyes that received the glue was 104.7 mm Hg with a mean of 101.4 +/- 3.2 mm Hg. None of the eyes in which glue was used showed leakage. At confocal microscopy, the glue was distributed inside the wound edges as a homogeneous thin layer of a less dense signal than that of the stroma. CONCLUSIONS: A novel chondroitin sulfate-aldehyde adhesive was shown to be effective ex vivo for sealing corneal incisions in rabbit eyes and was superior to sutures for this purpose.