Potential Savings from Visit Reduction of Continuous Intraocular Pressure Monitoring.

INTRODUCTION: A continuous method of measuring intraocular pressures (IOP) could be advantageous in the management of glaucoma. This report aims to analyze the potential savings from visit reduction of continuous IOP measurements obtained with an intraocular device. MATERIALS AND METHODS: We constructed a model adapted from a prior study based on the number of glaucoma patients among 5% of the Medicare population. RESULTS: We found that the implementation of a device that continuously measures IOP can result in a reduction of 23.21% in yearly costs from glaucoma outpatient visits. CONCLUSION: Continuous IOP monitoring has the potential to alleviate the economic burden of the current management structure of patients with glaucoma. CLINICAL SIGNIFICANCE: In an era of elevated healthcare costs, continuous IOP monitoring offers an option to improve the care of glaucoma patients through visit reduction, also resulting in a 23.21% reduction in yearly expenses related to glaucoma clinical visits.How to cite this article: Dong J, Syed ZA, Fan K, Yahya AF, Melki SA. Potential Savings from Visit Reduction of Continuous Intraocular Pressure Monitoring. J Curr Glaucoma Pract 2018;12(2):59-63.

Surgical adhesives in ophthalmology: history and current trends.

Tissue adhesives are gaining popularity in ophthalmology, as they could potentially reduce the complications associated with current surgical methods. An ideal tissue adhesive should have superior tensile strength, be non-toxic and anti-inflammatory, improve efficiency and be cost-effective. Both synthetic and biological glues are available. The primary synthetic glues include cyanoacrylate and the recently introduced polyethylene glycol (PEG) derivatives, while most biological glues are composed of fibrin. Cyanoacrylate has a high tensile strength, but rapidly polymerises upon contact with any fluid and has been associated with histotoxicity. Fibrin induces less toxic and inflammatory reactions, and its polymerisation time can be controlled. Tensile strength studies have shown that fibrin is not as strong as cyanoacrylate. While more research is needed, PEG variants currently appear to have the most promise. These glues are non-toxic, strong and time-effective. Through MEDLINE and internet searches, this paper presents a systematic review of the current applications of surgical adhesives to corneal, glaucoma, retinal, cataract and strabismus surgeries. Our review suggests that surgical adhesives have promise to reduce problems in current ophthalmic surgical procedures.

Accuracy of Visual Estimation of LASIK Flap Thickness.

PURPOSE: To assess the accuracy of surgeons' visual estimation of LASIK flap thickness when created by a femtosecond laser by comparing it to ultrasound measurements. METHODS: Surgeons were asked to visually estimate the thickness of a femtosecond flap during the procedure. Total corneal thickness was measured by ultrasound pachymetry prior to the procedure and the stromal bed was similarly measured after flap lifting. The estimates from three experienced surgeons (cornea fellowship trained and more than 5 years in practice) were compared to those of three cornea fellows, with each surgeon evaluating 20 eyes (120 total). Surgeons were not told the thickness of the flaps unless required for safety reasons. RESULTS: The average difference between visual and ultrasonic estimation of LASIK flap thickness was 15.20 µm. The flap was 10 µm thicker than estimated in 37% of eyes, 20 µm thicker in 17% of eyes, and 30 µm thicker in 10% of eyes. The largest deviation was 53 µm. There was no statistically significant difference between the accuracy of experienced surgeons and fellows (P = .51). CONCLUSIONS: There are significant differences between surgeons' visual estimates and ultrasonic measurements of LASIK flap thickness. Relying on these visual estimates may lead to deeper excimer laser ablation than intended. This could lead to thinner residual stromal beds and higher percent tissue altered than planned. The authors recommend that surgeons measure flaps intraoperatively to maximize accuracy and safety. [J Refract Surg. 2017;33(11):765-767.].

Risk Factors for Retreatment Following Myopic LASIK with Femtosecond Laser and Custom Ablation for the Treatment of Myopia.

PURPOSE: To identify risks factors for retreatment post-laser in situ keratomeliusis (LASIK). MATERIALS & METHODS: A retrospective chart review from December 2008 to September 2012 identified 1,402 patients (2,581 eyes) that underwent LASIK treatment for myopia with the Intralase™ FS, STAR S4 IR™ Excimer Laser, and WaveScan WaveFront™ technology. In this group, 83 patients were retreated. All charts were reviewed for preoperative age, gender, initial manifest refraction spherical equivalent (MRSE), total astigmatism, and iris registration. RESULTS: Increased incidence rates of retreatment post-LASIK were preoperative age >40 years (p < 0.001), initial MRSE > -3.0 D (p = 0.02), and astigmatism >1D (p = 0.001). Iris registration capture did not significantly reduce the retreatment rate (p = 0.12). CONCLUSIONS: Risk factors for retreatment included preoperative age >40 years, initial MRSE > -3.0 D, and astigmatism >1D. There was no difference in retreatment rate for patients based on gender or iris registration capture.

Risk factors for loss of epithelial flap integrity in laser-assisted subepithelial keratectomy surgery.

PURPOSE: To evaluate risk factors leading to loss of epithelial flap integrity in laser-assisted subepithelial keratectomy (LASEK). SETTING: Boston Eye Group, Brookline, Massachusetts, USA. DESIGN: Retrospective case study. METHODS: This retrospective chart review was performed for LASEK surgeries that occurred between January 2009 and October 2013. Logistic regression was performed to determine whether epithelium preservation was correlated with age, sex, sphere, cylinder, spherical equivalent (SE), keratometry, and central corneal thickness (CCT). RESULTS: The study reviewed 1009 eyes of 509 patients with a mean age of 29.1 years ± 12.2 (SD). The mean preoperative spherical refraction was -4.7 ± 2.5 diopters (D), and the mean preoperative cylinder was -1.1 ± 0.8 D. The mean preoperative decimal corrected distance visual acuity was 1.01 ± 0.07. Single-sheet mobilization of the loosened epithelium flap was found in 72.3% of cases. Fragmented preservation events occurred in 17.6% of cases; the flap was discarded in 10.0% of cases. Epithelium preservation was significantly correlated with age (P = .048) but not with other parameters (P > .05 for sex, sphere, cylinder, SE, keratometry, CCT, and surgeon experience). Epithelial flap dissection was less likely to lead to a single epithelial sheet in patients older than 50 years than in younger patients (56.3% versus 74.9%). The mean postoperative decimal uncorrected distance visual acuity (UDVA) at 3 months was 0.98 ± 0.08. There was no statistical difference in postoperative UDVA between the undiscarded flap group and discarded flap group (P = .128). CONCLUSION: Successful dissection of single-sheet epithelial flap diminished with age. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Cataract surgery outcomes at a UK independent sector treatment centre.

BACKGROUND/AIMS: The goal of this study was to review cataract surgery outcomes at three independent surgery treatment centres established by the UK Specialist Hospitals (UKSH) and to compare these outcomes with recognised benchmarks. METHODS: All patients who underwent cataract surgery at UKSH between July 2005 and March 2013 were included. Complication rates were obtained using annual quality reports, logbooks kept in operating theatres and outpatient departments, and electronic medical records. Refractive outcomes and biometry results between December 2010 and March 2013 were obtained from electronic medical records. Results were compared with previously published benchmarks. RESULTS: This study reviewed 20,070 cataract surgeries. UKSH had lower rates of several operative complications compared with the Cataract National Dataset benchmark study. These included choroidal haemorrhage, hyphaema, intraocular lens complications, iris damage from phacoemulsification, nuclear fragment into the vitreous, phacoemulsification wound burn, posterior capsule rupture or vitreous loss or both, vitreous in anterior chamber, and zonular dialysis. UKSH had lower rates of postoperative complications including corneal decompensation, cystoid macular oedema, iris to wound, posterior capsule opacification with yttrium aluminium garnet indicated, raised intraocular pressure, retained soft lens matter, uveitis, vitreous to section, and wound leak. Biometry outcomes at UKSH were significantly better than recently published benchmarks from the National Healthcare Service. CONCLUSIONS: This is the first large-scale retrospective study of cataract surgery outcomes in the UK independent sector. The results indicate comparable or lower rates for most complications as compared with data collected in a previously published study.

Anterior chamber gas bubble emergence pattern during femtosecond LASIK-flap creation.

AIM: To characterise the emergence pattern of cavitation bubbles into the anterior chamber (AC) following femtosecond laser-assisted in situ keratomileusis (LASIK)-flap creation METHODS: Retrospective review of patients undergoing femtosecond LASIK surgery at Boston Laser, a private refractive surgery practice in Boston, Massachusetts, between December 2008 and February 2014. Patient charts were reviewed to identify all cases with gas bubble migration into the AC. Surgical videos were examined and the location of bubble entry was recorded separately for right and left eyes. RESULTS: Five thousand one hundred and fifty-eight patients underwent femtosecond LASIK surgery. Air bubble migration into the AC, presumably via the Schlemm's canal and trabecular meshwork, occurred in 1% of cases. Patients with AC bubbles had an average age of 33±8 years with a measured LASIK flap thickness of 96±21 µm. The occurrence of gas bubbles impaired iris registration in 64% of cases. Gas bubbles appeared preferentially in the nasal or inferior quadrants for right (92% of cases) and left (100% of cases) eyes. This bubble emergence pattern is significantly different from that expected with a random distribution (p<0.0001) and did not seem associated with decentration of the femtosecond laser docking system. CONCLUSIONS: The migration of gas bubbles into the AC is a rare occurrence during femtosecond laser flap creation. The preferential emergence of gas bubbles into the nasal and inferior quadrants of the AC may indicate a distinctive anatomy of the nasal Schlemm's canal.

Successful femtosecond LASIK flap creation despite multiple suction losses.

We present a case of successful completion of a laser in situ keratomileusis (LASIK) procedure despite 5 episodes of suction loss during femtosecond flap creation in a 30-year-old man with no risk factors. The patient had an uncorrected distance visual acuity of 20/20 in both eyes at his 2-month follow-up visit. Our experience in this case shows that multiple suction losses during femtosecond LASIK flap creation do not preclude completion of a successful procedure with excellent visual outcomes. Caution and technique modification are advised if multiple laser passes are applied to avoid creating multiplanar flaps.

Corneal perforation by an astigmatic keratotomy performed with an optical coherence tomography-guided femtosecond laser.

UNLABELLED: We present a case of corneal perforation secondary to an intrastromal astigmatic keratotomy performed with an optical coherence tomography-guided femtosecond laser. The keratotomy was concomitant with cataract surgery and resulted in a flat anterior chamber prior to the start of lens extraction. Interrupted nylon sutures were placed to seal the keratotomy prior to phacoemulsification. Escape of cavitation bubbles into the anterior chamber or the liquid interface can alert the surgeon to the possibility of unintended perforation of the endothelium or the epithelium, respectively. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.

Intraocular pressure fluctuation and glaucoma progression: what do we know?

While mean intraocular pressure (IOP) has long been known to correlate with glaucomatous damage, the role of IOP fluctuation is less clearly defined. There is extensive evidence in the literature for and against the value of short-term and long-term IOP fluctuation in the evaluation and prognosis of patients with glaucoma. We present here the arguments made by both sides, as well as a discussion of the pitfalls of prior research and potential directions for future studies. Until a reliable method is developed that allows for constant IOP monitoring, many variables will continue to hinder us from drawing adequate conclusions regarding the significance of IOP variation.

Gamma-irradiated corneas as carriers for the Boston type 1 keratoprosthesis: advantages and outcomes in a surgical mission setting.

PURPOSE: The Boston keratoprosthesis (KPro) is the most commonly used KPro worldwide. There are limited data on the outcomes when irradiated corneas are used as KPro carriers. We report a retrospective analysis of corneal transplantations performed in a regular surgical mission setting in Beirut, Lebanon, using the Boston KPro type 1 and gamma-irradiated carrier corneas, and we describe visual outcomes, complications, and retention percentage. METHODS: We conducted a retrospective analysis of 17 consecutive eyes from 16 patients who underwent Boston KPro type 1 implantation at the Beirut Eye Specialist Hospital between December 2010 and July 2012. Patient medical records were reviewed for preoperative, intraoperative, and postoperative details. RESULTS: Postoperatively, 9 (52.9%), 5 (29.4%), and 2 (11.7%) eyes had a corrected visual acuity of 20/400 or better, 20/100 or better, and 20/40 or better, respectively, at the most recent follow-up visit. A total of 16 eyes (94.1%) improved in corrected visual acuity over the course of follow-up. Overall, 13 eyes (76.4%) developed at least 1 complication after surgery. Retroprosthetic membrane formation was the most common complication, occurring in 10 eyes (58.8%). Neither infectious keratitis nor corneal stromal necrosis was noted during the follow-up period. The retention percentage was 94.1%. CONCLUSIONS: The visual acuity outcomes, incidence of complications, and retention percentage of the KPro using gamma-irradiated carrier corneas are comparable with the outcomes of KPro implantation reported in the literature using fresh grafts as carriers. KPro with irradiated corneal carrier grafts seems to be an effective option to increase the supply of transplantation suitable corneas in remote areas, where fresh corneal grafts may be scarce.

Sandwich fibrin glue technique for attachment of conjunctival autograft during pterygium surgery.

OBJECTIVE: To report the results of a sandwich application of fibrin glue compared with the standard method of using fibrin glue for the attachment of the conjunctival autograft in pterygium surgery. PARTICIPANTS: The study group consisted of 56 consecutive eyes with primary pterygium. METHODS: We performed a retrospective analysis comparing the standard method of using fibrin glue for the attachment of the conjunctival autograft during pterygium excision surgery versus the "sandwich technique." In the "sandwich technique," the thrombin component of the fibrin glue was applied after the graft was secured in position over a bed of fibrinogen. RESULTS: Graft dehiscence occurred in 3 eyes in the conventional group only. Recurrence occurred in 2 eyes in the conventional group and 1 eye in the sandwich group. None of the values reached statistical significance. CONCLUSIONS: The sandwich technique simplifies conjunctival graft fixation during pterygium surgery with conjunctival autograft by allowing more time to properly position the autograft before fibrin clot formation.

Loose anchoring suture to secure a free flap after laser in situ keratomileusis.

UNLABELLED: We describe the use of a single loose anchoring suture to secure a free flap with good outcomes. We believe this simple, safe technique combines the advantages of previously reported methods, including stability and minimal invasiveness. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.

Inadvertent LASIK flap creation over a soft contact lens.

PURPOSE: To report the findings and outcomes in two cases in which a contact lens was inadvertently present during creation of a LASIK corneal flap. METHODS: Interventional case report. RESULTS: A soft contact lens blocked the successful creation of the corneal flap with a femtosecond laser in one patient. Repeat surgery 1 week later resulted in a normal flap. In the second patient, a thin but normal-shaped flap was successfully created using a microkeratome despite the presence of a soft contact lens in the patient's eye. No adverse effect on vision was noted in either case. CONCLUSIONS: Refractive surgeons are encouraged to establish or review current procedures to ensure adequate contact lens removal prior to LASIK surgery, as it may result in an aborted procedure or a potentially thin and/or irregular corneal flap.

Intraocular pressure measurement by radio wave telemetry.

PURPOSE: To determine the biocompatibility of a new wireless intraocular pressure (IOP) transducer (WIT) in rabbit eyes and to correlate its measurements with other pressure-measuring devices. METHODS: The WIT is a ring-shaped intraocular device that allows wireless IOP measurements through radiofrequency. It was implanted into six eyes of New Zealand White rabbits after extracapsular lens extraction. A sham rabbit eye with no transducer implanted was used as a control. The animals were observed and examined by microscopy at various intervals up to 25 months after surgery. IOP was measured at various intervals by pneumotonometry, tonometry, WIT, and manometry. The data from the various devices were compared and analyzed for reproducibility. Two eyes were enucleated at 5.5 and 20 months after implantation and analyzed by histology. RESULTS: The WIT appears to be well tolerated in the rabbit eye, with no evidence of significant inflammation or scar formation by microscopic in vivo examination. Histology did not reveal intraocular inflammation or membrane formation. Repeated IOP measurements with pneumotonometry, tonometry, and the WIT resulted in SDs of 2.70 mm Hg, 3.35 mm Hg, and 0.81 mm Hg, respectively. The concordance between the WIT and direct manometry measurements was high. A downward drift in IOP measured by the WIT was noted in three rabbits, necessitating recalibration. CONCLUSIONS: The WIT is well tolerated by the rabbit eye. Its measurements are reproducible and in close concordance with manometry. A downward IOP drift warrants further investigation.

Maddox rod effect to confirm the visual significance of laser in situ keratomileusis flap striae.

UNLABELLED: Laser in situ keratomileusis (LASIK) flap striae can act as a Maddox rod, producing streaks of light perpendicular to the orientation of the striae. This phenomenon can be used in the diagnostic and surgical decision-making process after LASIK. We correlated persistent complaints of starburst by a patient to the presence of LASIK flap striae in both eyes. The more severe striae were subsequently treated with phototherapeutic keratectomy, with complete resolution of symptoms. The LASIK flap striae-induced Maddox rod effect can be used as a simple and useful method with high diagnostic and therapeutic value. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.

Coaxially sighted intraocular lens light reflex for centration of the multifocal single piece intraocular lens.

Centration of multifocal Intraocular lenses (IOL) may be critical to ensure optimal function and prevent untoward side effects. Pharmacologic pupillary dilation and constriction may shift the physiologic location of the pupillary center rendering intraoperative positioning of multifocal IOL challenging. Similarly, the anterior capsular center is difficult to pinpoint and may not correspond to either the visual axis or the pupillary center. The visual axis is the only landmark that can be consistently identified prior, during and after cataract surgery. Centering diffractive multifocal IOL on the visual axis may allow more consistent placement and better outcome measures. In the following, we describe a simple technique to center multifocal single piece acrylic IOLs on the visual axis.