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Craig N Czyz,1 Thomas S Bacon,2 Andrew W Stacey,3 Eva N Cahill,4 Bryan R Costin,5 Boris I Karanfilov,6 Kenneth V Cahill5 1Section Oculofacial Plastic and Reconstructive Surgery, Ohio University/OhioHealth, 2Department of Medical Education, Mount Carmel Health Systems, Columbus, OH, USA; 3Department of Ophthalmology, University of Michigan, Ann Arbor, MI, USA; 4Department of Biology, Wittenberg University, Springfield, OH, USA; 5Department of Ophthalmology, William H Havener Eye Institute, Ohio State University Wexner Medical Center, Columbus, OH, USA; 6The Sinus Institute of Ohio, Dublin, OH, USA Purpose: To determine the impact of patient positioning and scan orientation on the appearance of air in the nasolacrimal drainage system on computed tomography (CT) imaging, and the repeatability of the observations.Methods: This was a retrospective analysis of CT images for 92 patients.Results: Air was found to be present more fully in the upright-position group as compared with the supine-position group. Comparing axial and coronal scan orientation, no difference in aeration was found, except for the nasolacrimal duct in the upright-position group.Conclusion: Patient position should be accounted for in diagnostic conclusions and treatment decisions based on CT. Keywords: axial, coronal, nasolacrimal sac, nasolacrimal duct

Detection of greenhouse gases is essential because harmful gases in the air diffuse rapidly over large areas in a short period of time, causing air pollution that will induce climate change with catastrophic consequences over time. Among the materials with favorable morphologies for gas detection (nanofibers, nanorods, nanosheets), large specific surfaces, high sensitivity and low production costs, we chose nanostructured porous films of In2O3 obtained by the sol-gel method, deposited on alumina transducers, with gold (Au) interdigitated electrodes (IDE) and platinum (Pt) heating circuits. Sensitive films contained 10 deposited layers, involving intermediate and final thermal treatments to stabilize the sensitive film. The fabricated sensor was characterized using AFM, SEM, EDX and XRD. The film morphology is complex, containing fibrillar formations and some quasi-spherical conglomerates. The deposited sensitive films are rough, thus favoring gas adsorption. Ozone sensing tests were performed at different temperatures. The highest response of the ozone sensor was recorded at room temperature, considered to be the working temperature for this specific sensor.

Sensor systems for monitoring indoor air quality are vital for the precise quantification of the mechanisms which lead to the deterioration of human health, with a typical person spending an average of 20 h a day in an enclosed space. Thus, a series of layered chemoresistive sensors, obtained by the facile electrodeposition of carbon nanomaterial-enhanced PANI composites, have been tested for the selective detection of two core indoor pollutants: ammonia and nitrogen dioxide. The sensors were tested with respect to sensitivity and selectivity to the target gasses, with performance being assessed based on response linearity and repeatability at room temperature. Of the tested sensors, two have been identified as having an adequate performance on ammonia, with sensitivities of up to 96.99% and resolutions of up to 0.85 ppm being observed, while on nitrogen dioxide, despite the successful sensor having a lower sensitivity, 10.71%, it has shown high resolution, 1.25 ppm, and linearity over a large concentration domain. These high performances highlight the viability of multi-layers chemosensors based on the electrodeposition of nanomaterial-enhanced conductive polymers for the detection of pollutant gasses, with finetuning of the detection layer allowing the accurate monitoring of a wide range of gasses.

A series of SnO2–ZnO composite nanostructured (thin) films with different amounts of SnO2 (from 0 to 50 wt %) was prepared and deposited on a miniaturized porous alumina transducer using the sol–gel and dip coating method. The transducer, developed by our research group, contains Au interdigital electrodes on one side and a Pt heater on the other side. The sensing films were characterized using SEM and AFM techniques. Highly toxic and flammable gases (CO, CO2, CH4, and C3H8) were tested under lab conditions (carrier gas was dry air) using a special gas sensing cell developed by our research group. The gas concentrations varied between 5 and 2000 ppm and the optimum working temperatures were in the range of 210–300 °C. It was found that the sensing performance was influenced by the amount of oxide components present in the composite material. Improved sensing performance was achieved for the ZnO (98 wt %)–SnO2 (2 wt %) composite as compared to the sensors containing only the pristine oxides. The sensor response, cross-response and recovery characteristics of the analyzed materials are reported. The high sensitivity (RS = 1.21) to low amounts of CO (5 ppm) was reported for the sensor containing a composite sensitive film with ZnO (98 wt %)–SnO2 (2 wt %). This sensor response to CO was five times higher as compared to its response to CO2, CH4, and C3H8, thus the sensor is considered to be selective for CO under these test conditions.

Developing a sensing layer with high electroactive properties is an important aspect for proper functionality of a wearable sensor. The polymeric nanocomposite material obtained by a simple electropolymerization on gold interdigitated electrodes (IDEs) can be optimized to have suitable conductive properties to be used with direct current (DC) measurements. A new layer based on polyaniline:poly(4-styrenesulfonate) (PANI:PSS)/single-walled carbon nanotubes (SWCNT)/ferrocene (Fc) was electrosynthesized and deposed on interdigital transducers (IDT) and was characterized in detail using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoemission spectroscopy (XPS), and X-ray diffraction (XRD). The sensor characteristics of the material towards carbon monoxide (CO) in the concentration range of 10–300 ppm were examined, showing a minimal relative humidity interference of only 1% and an increase of sensitivity with the increase of CO concentration. Humidity interference could be controlled by the number of CV cycles when a compact layer was formed and the addition of Fc played an important role in the decrease of humidity. The results for CO detection can be substantially improved by optimizing the number of deposition cycles and enhancing the Fc concentration. The material was developed for selective detection of CO in real environmental conditions and shows good potential for use in a wearable sensor.

The following paper describes the design and functions of a miniaturized integrated platform for optical and electrical monitoring of cell cultures and the necessary steps in the fabrication and testing of a silicon microchip Micro ElectroMechanical Systems (MEMS)-based technology for cell data recording, monitoring and stimulation. The silicon microchip consists of a MEMS machined device containing a shank of 240 μm width, 3 mm long and 50 μm thick and an enlarged area of 5 mm × 5 mm hosting the pads for electrical connections. Ten platinum electrodes and five sensors are placed on the shank and are connected with the external electronics through the pads. The sensors aim to monitor the pH, the temperature and the impedance of the cell culture. The electrodes are bidirectional and can be used both for electrical potential recording and stimulation of cells. The fabrication steps are presented, along with the electrical and optical characterization of the system. The target of the research is to develop a new and reconfigurable platform according to the particular applications needs, as a tool for the biologist, chemists and medical doctors working is the field of cell culture monitoring in terms of growth, maintenance conditions, reaction to electrical or chemical stimulation (drugs, toxicants, etc.). HaCaT (Immortalised Human Keratinocyte) cell culture has been used for demonstration purposes in order to provide information on the platform electrical and optical functions.

Purpose: To determine the effect of intravenous mannitol on globe and orbital volumes., Methods: Retrospective chart review of a consecutive series of Cleveland Clinic Neurosurgical Intensive Care Unit patients who underwent computed tomographic imaging before and after intravenous mannitol administration. Volume measurements were performed according to a previously described technique by averaging axial image areas. Measurements before and after mannitol administration were compared using paired t-test., Results: Fourteen patients (28 eyes) met inclusion criteria. Average globe volume decreased 186 mm 3 (-2.5%, p = 0.02) after mannitol administration, while average orbital volume increased 353 mm 3 (+3.5%, p = 0.04). Average globe volume change for subjects with follow-up scan less than 4.7 hours (mean 1.9 hours; range 0.2-4.5 hours) after mannitol administration was -125 mm 3 (-1.7%, p = 0.24) and average orbital volume change was +458 mm 3 (+5.1%, p = 0.11). Average globe volume change after mannitol administration for those with follow-up more than 4.7 hours (average 13.9 hours, range 4.9-24.7 hours) was -246 mm 3 (-3.3%, p = 0.05) and orbital volume change was +248 mm 3 (+2.2%, p = 0.24). Dividing the study population into groups based on mannitol dose did not yield any statistically significant change., Conclusions: Human globe volume decreases after intravenous mannitol administration, while orbital volume increases. These volume changes occur during the time period when intraocular pressure normalizes, after the pressure-lowering effects of the drug. This novel volumetric information improves our understanding of mannitol's mechanism of action and its effects on human ocular and periocular tissues.

A 67-year-old male with a 35-year history of left-sided epiphora presented with a nonpainful, noninflamed, left medial canthal mass and complete left nasolacrimal obstruction. During routine dacryocystorhinostomy, a lesion was present within the lacrimal sac that mimicked a lacrimal stone in appearance but with a consistency concerning for malignancy. Histologically, the lesion displayed apple-green birefringence on polarized light microscopy and Congo red staining. The patient was referred to the hematology service for evaluation, which failed to reveal systemic disease. There is 1 previous report of localized amyloidosis to the nasolacrimal excretory system in which the lesion was invasive and caused bony erosion. The authors present a second case of localized, nasolacrimal amyloidosis mimicking both neoplasm and dacryolith without bony erosion.

Purpose: To investigate frontalis muscle asymmetry and characterize its lateral interdigitation with the orbicularis oculi muscle., Methods: After making a mid-coronal incision and bluntly dissecting to the orbital rim, the frontalis muscle was exposed, marked, and photographed. The right and left muscle bellies were analyzed and compared in both pixels and cm ratios generated with NIH ImageJ software. A ratio of ≥1.5 was considered significantly asymmetric. The lateral interdigitation of the frontalis and orbicularis oculi muscles was measured from the supraorbital notch with a metric ruler. Data were analyzed using 2-sample t tests, paired t tests, log scales, and nonparametric tests were performed for sensitivity analyses. A p value of ≤0.05 was considered statistically significant., Results: Fifty-eight hemifaces of 29 Caucasian cadavers were studied for muscle belly asymmetry. Thirty-six hemifaces of 18 Caucasian cadavers (9 males) were dissected for lateral landmarks and average age of these specimens was 73 years (range: 35-91 years). Significant asymmetry in muscle belly area was found in 6/29 (20%) specimens, with the right muscle belly larger in all 6 specimens. On average, the right muscle belly area was 1.23 times that of the left (p = <0.001). The average frontalis-orbicularis interdigitation occurred 3.4 cm lateral to the supraorbital notch., Conclusions: Significant frontalis muscle belly asymmetry exists in 20% of Caucasians cadavers. The right muscle belly was larger on average and in all cases of significant asymmetry. The frontalis muscle interdigitates with the orbicularis oculi on average 3.4 cm lateral to the supraorbital notch.

Purpose: To investigate variation in aeration of the nasolacrimal drainage system between age groups and genders, and to report the reliability of repeated aeration grading and nasolacrimal canal measurements on CT., Methods: Retrospective review of CT images from 92 individuals, 60 female and 32 male, was conducted by 3 independent reviewers for the presence of air within the nasolacrimal drainage system. Diameter and area measurements were also obtained at the smallest identifiable portion of the nasolacrimal canal by 2 independent reviewers., Results: When air is present on CT, it is seen more fully throughout the nasolacrimal system in men as compared to women. Age data demonstrate that patients from the third and fourth decade have significantly more aeration than older patients. Diameter and area of the nasolacrimal duct within the canal at its narrowest point revealed no correlation with sex, age, or nasolacrimal system aeration. Inter-reviewer reliability shows strong repeatability of aeration grading and nasolacrimal duct measurements between multiple reviewers., Conclusions: The results suggest CT is reliable and repeatable modality to assess nasolacrimal system aeration and nasolacrimal duct diameter. Decreased aeration of the nasolacrimal system in females and the elderly mirrors epidemiologic trends for those at risk to develop primary acquired nasolacrimal duct obstruction. Variables in nasolacrimal drainage system anatomy, specifically nasolacrimal duct diameter and area, did not vary between sexes or age groups, suggesting aeration may be an overlooked variable in nasolacrimal system function.

Purpose: To investigate and compare the histologic compositions of the pretarsal, preseptal, and orbital orbicularis oculi muscle (OOM) using nonpreserved, fresh-frozen, human cadavers., Methods: The OOM was exposed using sharp and blunt dissection. A metric ruler was used to measure and mark 0.5 cm × 1 cm samples from each portion of the right, superior OOM. Samples were excised, fixed in formalin, and completely embedded in paraffin. Five-micrometer-thick, hematoxylin- and eosin-stained sections were generated for each sample and analyzed by an anatomical pathologist. The relative percentages of the 4 main tissue types (skeletal muscle, fibrous tissue, adipose tissue, and neurovascular tissue) were quantified., Results: Forty-two samples were obtained from 14 Caucasian cadavers. On average, the pretarsal samples were composed of 83.5% skeletal muscle, 0.0% adipose, 5.0% neurovascular, and 11.5% fibrous tissue. Average preseptal OOM was 46.5% skeletal muscle, 12.7% adipose, 9.2% neurovascular, and 31.5% fibrous tissue. The orbital OOM was, on average, 42.7% skeletal muscle, 32.7% adipose tissue, 6.9% neurovascular, and 17.7% fibrous tissue., Conclusions: The OOM represents a histologically heterogeneous structure.

Purpose: To determine the gross and histologic configurations of the medial and lateral frontalis muscle., Methods: After making a midcoronal incision and bluntly dissecting to the orbital rim, the frontalis muscle was marked and measured. A protractor was used to measure the frontalis-orbicularis angle (FOA) and, when present, the angle of central bifurcation (AOB). Three strips of full-thickness forehead soft tissue measuring 0.5 cm × 8 cm were excised 3, 4.5, and 6 cm above the supraorbital notch and analyzed histologically for the presence of skeletal muscle fibers. Data were analyzed using 2-sample t tests, paired t tests, Pearson correlations, and mixed effect models. A p value of ≤ 0.05 was considered statistically significant., Results: Sixty-four hemifaces of 32 cadavers (16 males) were dissected. All specimens were Caucasian. The average age was 78.2 years (range, 56-102 years). The average FOA was 88.7° (13.0°), and the average AOB was 90.0° (26.4°). A visible midline bifurcation occurred in 28 of 32 subjects (88%) at an average height of 4.7 cm (range, 2.4-7.2 cm) superior to the supraorbital notch. Continuous skeletal muscle fibers were present within the midline bifurcation histologically in 89%, 75%, and 11% of specimens 3.5, 5.0, and 6.5 cm above the supraorbital notch, respectively. In 46% of individuals, skeletal muscle fibers were continuously present microscopically within the gross bifurcation., Conclusion: While a medial frontalis muscle bifurcation occurs grossly in most senescent Caucasians, muscle fibers exist microscopically within this zone in nearly half of individuals.

Purpose: To describe a novel technique to correct lateral eyebrow ptosis using a frontalis muscle transposition flap., Methods: The charts of all patients undergoing eyebrow ptosis repair using a frontalis muscle transposition flap from December 2013 through April 2014 were reviewed to describe the surgical technique., Results: Sixteen patients underwent eyebrow ptosis repair using a frontalis muscle pedicle flap during the study period. Briefly, after local infiltration, a lateral forehead rhytid was marked and incised for approximately 1.5 cm. Blunt dissection exposed the frontalis-orbicularis angle, the frontalis-orbicularis insertion, and the lateral extent of the frontalis muscle. A pedicle flap of lateral frontalis muscle was created, trimmed, and transposed laterally in graded fashion to achieve the optimal eyebrow height and contour. The incision was closed with 5-0 polypropylene suture. All patients reported improvement in eyebrow position., Conclusions: This novel technique provides frontalis muscle elevatory force to the lateral eyebrow through a small incision to improve eyebrow ptosis. Further study, including objective measures of long-term results, is required.

Background: To determine the safety and effectiveness of full thickness eyelid reconstructions using a semicircular rotational flap without reconstructing the posterior lamella., Methods: The charts of all patients undergoing semicircular flap closure of full thickness eyelid defects by one surgeon (JDP) at the Cole Eye Institute between March 2000 and October 2012 were reviewed. Charts were reviewed for patient demographic information, as well as for the size of the defect, the type of flap used, length of follow-up and complications., Results: Fifty eyelids of 50 patients underwent a semicircular flap repair without posterior lamellar reconstruction during the study period, and 41 charts were available for review. Average patient age was 74 years (range, 40-92 years). Average follow-up was 9.8 months (range, 1-84 months). Average defect size was 19.1 mm (range, 14-30 mm, SD 4.6). Complications included pyogenic granuloma (10 patients, 24.4%), exposure keratopathy (7 patients, 17.1%) lagophthalmos (5 patients, 12.2%), ectropion (6 patients, 14.6%), lateral canthal dystopia (2 cases, 4.9%), eyelid notch (2 cases, 4.9%) and trichiasis (4 cases, 9.8%). Two patients underwent subsequent tarsorrhaphy and one patient underwent ectropion repair. There were no cases of wound dehiscence, diplopia or fornix inadequacy, and the recruited aspect of the eyelid healed well in each case. No case required reconstruction of the eyelid margin or fornix., Conclusions: Semicircular flap repair of full thickness eyelid defects without flap or graft repair of the posterior lamella results in an adequate fornix and a low rate of secondary surgery.

Purpose: To determine the safety and effectiveness of intralesional tetracycline 2% injection for the treatment of lower eyelid festoons., Methods: The authors retrospectively reviewed the charts of all patients undergoing tetracycline 2% injection of lower eyelid festoons at the Cole Eye Institute from August 2008 to August 2013. Charts were reviewed for patient demographic data, dose and number of tetracycline injections, follow-up interval, the presence of preinjection and postinjection photographs, and complications. Charts without preinjection and postinjection photographs were excluded from review. The preinjection and postinjection photographs were randomized, masked, and graded by 4 independent examiners. Photographs were graded on a scale of 0 (no festoon) to 4 (severe festoon). Student t test was used for statistical analysis., Results: Eleven patients met inclusion criteria. Each patient underwent bilateral injection. Average follow up was 121 days (range, 18-586 days). Patients received up to 0.75 ml (mean, 0.24 ml) of tetracycline 2% per side. Average preinjection grade was 2.1 (standard deviation, 0.89; range, 0-3), and average postinjection grade was 1.2 (standard deviation, 0.72; range, 0-2; p < 0.001). Three patients had follow up less than 60 days (mean, 34 days), with an average preinjection grade of 1.96 and postinjection grade of 1.23 (p < 0.001). Five patients had follow up between 60 and 100 days (mean, 82 days), with an average preinjection grade of 2.18 and postinjection grade of 1.38 (p < 0.001). Three patients had follow up longer than 100 days (mean, 275 days), with an average preinjection grade of 2.08 and postinjection grade of 0.78 (p < 0.001). Complications other than pain and bruising were not identified in any patient., Conclusions: Intralesional tetracycline 2% injection may offer a safe option to treat lower eyelid festoons. Complications such as cutaneous ischemia or necrosis were not identified in any patient. Further study may determine optimal treatment doses and intervals and detect infrequent but significant complications.

A previously healthy 1-year-old boy presented with a right lower eyelid abscess. Oral and topical antibiotics were initiated, and the lesion was drained and explored. Despite medical and surgical treatment, the abscess failed to resolve completely and formed again 1 month later. A second incision and drainage procedure was performed, and Candida albicans grew in cultures. Additional workup revealed severe neutropenia with an absolute neutrophil count of 0.18 k/μl (1.19-7.21 k/μl). The abscess resolved after 2 weeks of oral fluconazole. C. albicans eyelid abscess may be the presenting sign of systemic immunodeficiency.

Purpose: To evaluate the safety of onabotulinum toxin A injected into the central upper eyelid and eyebrow regions., Methods: The authors retrospectively reviewed the charts of all patients undergoing onabotulinum toxin A injection to the central upper eyelid and eyebrow between February, 2012, and November, 2012. Age, gender, indication, injection sites, number of central units, total number of units, and occurrence of adverse events were all recorded., Results: A total of 300 procedures on 88 patients were performed, in whom the central upper eyelid and/or central eyebrow was injected with onabotulinum toxin A. There were 68 female and 20 male patients. Average age was 68.7±13.3 years (range, 42-92 years). Indications for central eyelid/eyebrow treatment included blepharospasm (34 patients, 176 procedures), hemifacial spasm (21 patients, 40 procedures), facial nerve disorders (2 patients, 9 procedures), and facial rhytides/eyebrow ptosis (31 patients, 75 procedures). The amount of neurotoxin injected into the central eyelid and eyebrow ranged from 2 to 12.5 units per encounter. Complications included diplopia (4% of total encounters), lagophthalmos (1% of total encounters), blepharoptosis (1% of total encounters), and blurry vision (1% of total encounters). Minor local effects, including bruising, bleeding, pain, and mild swelling, were recorded in 3.3% of total encounters., Conclusions: Placement of onabotulinum toxin A into the central upper eyelid and eyebrow is associated with a low rate of blepharoptosis. Central eyelid and eyebrow neurotoxin injection can be safely added to the regimen when treatment calls for chemodenervation of the central orbicularis oculi.

Purpose: To compare the accuracy of indocyanine green (ICG)-guided sentinel lymph node biopsy to sentinel lymph node biopsy performed with technetium-99m in eyelid and in conjunctival malignancies., Methods: Review of a consecutive series of adult patients undergoing sentinel lymph node biopsy for eyelid and conjunctival malignancies between 2009 and 2013. Only patients undergoing both ICG-guided and technetium-99m-guided sentinel lymph node biopsies were included., Results: Five patients were identified: 3 women and 2 men. Four had conjunctival melanoma and 1 had eyelid melanoma. ICG aided in localization and confirmation of the sentinel nodes identified by technetium-99m, and all sentinel lymph nodes identified by technetium-99m were identified by ICG. All patients who underwent both sentinel lymph node modalities had negative lymph node biopsies for micrometastasis, but metastatic disease eventually developed in 1 patient. No safety concerns were identified with the use of ICG in the ocular adnexal region., Conclusions: For certain periocular malignancies, ICG-guided sentinel lymph node biopsy safely identifies sentinel lymph nodes intraoperatively possibly to a similar extent compared with technetium-99m-guided methods.

A 66-year-old woman presented with a blind, painful, hypertensive, and proptotic left eye. Computed tomographic imaging revealed a well-circumscribed mass involving the left orbit and globe. Metastatic work-up failed to reveal extraorbital lesions and the tumor was removed in toto via an evisceration approach orbitotomy. Histopathology and immunohistochemistry were most consistent with mammary-type myofibroblastoma with fascicles of bland, uniform spindle cells that stained positive for desmin and CD34. We are not aware of previous reports of orbital or ocular myofibroblastoma. This neoplasm has not been shown to recur, undergo malignant transformation, or metastasize. Familiarity with its clinical, histopathologic, and immunohistochemical features may improve diagnostic accuracy and treatment decisions for patients presenting with similar findings.

Purpose: To determine average dimensions of the orbicularis oculi muscle (OOM) from the orbital rim and to investigate polymorphic variations through anatomical dissection of nonpreserved, fresh-frozen human cadavers., Methods: The OOM was exposed using sharp and blunt dissection until its distal borders were identified. A metric ruler was used to measure the superior (S line), inferior (I line), and lateral (L line) dimensions of the OOM from the orbital rim. Data collection included age, gender, and race. Data were analyzed using 2-sample t tests, paired t tests, and mixed effect models. A p-value of ≤0.05 was considered statistically significant., Results: A total of 40 hemifaces of 20 cadavers were dissected. All specimens were Caucasian. Ten specimens were men. Average age was 73.9 years (56-92 years). The overall S line was 1.4 cm (95% confidence interval [CI], 1.23-1.57), the I line was 1.2 cm (95% CI, 1.00-1.36), and the L line was 2.5 cm (95% CI, 2.27-2.68). Men had significantly larger average T, L, and S line values than women (p = 0.003, 0.005, 0.008, respectively). I lines did not differ significantly between genders (p = 0.28)., Conclusions: In senescent Caucasians, the OOM extends approximately 1.4 cm superior, 1.2 cm inferior, and 2.5 cm lateral to the orbital rim. The muscle extends significantly further superiorly and laterally in Caucasian men than in women. Knowledge of the extent of the OOM should improve the understanding and the treatment of conditions affecting this region.

Purpose: To study differences in corneal biomechanical properties between primary open-angle glaucoma (POAG) and central corneal thickness (CCT)-matched control subjects and their effect on intraocular pressure (IOP) measurement., Methods: Thirteen eyes of 13 POAG subjects and 15 eyes of 15 normal subjects underwent corneal topography; IOP using Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), and corneal compensated IOP (IOPcc) using the Reichert ocular response analyzer (ORA); corneal hysteresis; and CCT. Results from POAG and control eyes were then compared using t tests., Results: Ages in the POAG group were slightly greater than that in the control group. CCT was closely matched between groups. Significant differences were found between GAT versus DCT and GAT versus IOPcc within both groups: Mean GAT IOP was not significantly different between POAG and controls, whereas mean DCT IOP did show a significant difference between groups as did mean IOPcc. The delta differences, GATΔDCT and GATΔIOPcc, were of greater magnitude in POAG subjects when compared with controls. Corneal hysteresis was significantly lower in POAG subjects., Conclusions: The delta differences between GAT and newer measures of IOP are greater in magnitude in patients with POAG than in the normal controls, independent of CCT. This is likely due to differences in the corneal biomechanical properties with POAG corneas being softer than healthy corneas, which causes greater underestimation of IOP by GAT in POAG than controls. Underestimation of IOP could affect treatment decisions and outcomes in POAG.

Purpose: To determine the effect of sub-Tenon injection on the length of optic nerve resected during enucleation., Methods: Case-control laboratory study on 22 orbits of 11 unpreserved, fresh-frozen human cadavers. Each cadaver underwent a conventional enucleation technique on one side and an otherwise identical technique on the contralateral side that included sub-Tenon injection of 2.5 ml normal saline in each oblique quadrant. Resected optic nerve lengths were measured and compared using Student t tests., Results: The mean optic nerve length was 15.2 mm (range, 5.0-21.0 mm) in the sub-Tenon injection group and 11.3 mm (range, 5.0-19.0 mm) in control group (p = 0.015)., Conclusions: Sub-Tenon injection during enucleation allows for significantly longer optic nerve resection lengths in unpreserved, fresh-frozen human cadavers.