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Purpose: With the growing popularity of badminton worldwide, the incidence of badminton-related ocular injuries is expected to rise. The high velocity of shuttlecocks renders ocular traumas particularly devastating, especially with the possibility of permanent vision loss. This study investigated the mechanism behind ocular complications through simulation analyses of mechanical stresses and pressures upon shuttlecock impact., Design: Computational simulation study., Participants: None., Methods: A 3-dimensional human eye model was reconstructed based on the physiological and biomechanical properties of various ocular tissues. Finite element analysis simulations involved a frontal collision with a shuttlecock projectile at 128.7 km/hour (80 mph). Intraocular pressure (IOP) changes and tissue stress were mapped and quantified in the following ocular structures: the limbus, ciliary body, zonular fibers, ora serrata, retina, and optic nerve head., Main Outcome Measures: Intraocular pressure and tissue stress., Results: Upon shuttlecock impact, compressive force was transferred to the anterior pole of the cornea, propagating posteriorly to the optic nerve head. Deflection of forces anteriorly contributed to refractory oscillations of compressive and tensile stress of ocular tissue. Initial impact led to a momentary (<1 ms) spike in IOP 5.66 MPa (42.5 × 10 3 mmHg) that radially distributed for a very brief instance (<1 ms) of pressure at the trabecular meshwork of the iridocorneal angle of 1.25 MPa (9.4 × 10 3 mmHg). The lens had a maximal posterior displacement of 1.5 mm with peak zonular fiber tensile strain of 52%. The limbus, ciliary body, and ora serrata had a peak tensile stress of 5.16 MPa, 1.90 MPa, and 0.62 MPa, respectively. Compressive force from the sclera concentrated at the optic nerve head for a peak stress of 5.97 MPa while peak pressure from vitreous humor was 7.99 MPa., Conclusions: Shuttlecock impact led to a very brief, substantial rise in pressure and stress significant for tissue damage and subsequent complications, such as secondary glaucoma, angle recession, lens subluxation, hyphema, or retinal dialysis. Our findings offer valuable mechanistic insights into how ocular structures are affected by shuttlecock projectile impact to inform clinical assessments and treatment strategies, while highlighting the importance of protective eyewear in racket sports., Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article., (© 2024 by the American Academy of Ophthalmology.) more...

Purpose: To investigate the use of super-resolution imaging techniques to enable telepathology using low-cost commercial cameras., Design: Experimental study., Participants: A total of 139 ophthalmic pathology slides obtained from the Ophthalmic Pathology service at the University of California, Irvine., Methods: Denoising Diffusion Probabilistic Model (DDPM) was developed to predict super-resolution pathology slide images from low-resolution inputs. The model was pretrained using 150 000 images randomly sampled from the ImageNet dataset. Patch aggregation was used to generate large images with DDPM. The performance of DDPM was evaluated against that of generative adversarial networks (GANs) and Robust UNet, which were also trained on the same dataset., Main Outcome Measures: The performance of models trained to generate super-resolution output images from low-resolution input images can be evaluated by using the mean squared error (MSE) and Structural Similarity Index Measure (SSIM), as well as subjective grades provided by expert pathologist graders., Results: In total, our study included 110 training images, 9 validation images, and 20 testing images. The objective performance scores were averaged over patches generated from 20 test images. The DDPM-based approach with pretraining produced the best results, with an MSE score of 1.35e-5 and an SSIM score of 0.8987. A qualitative analysis of super-resolution images was conducted by expert 3 pathologists and 1 expert ophthalmic microscopist, and the average accuracy of identifying the correct ground truth images ranged from 25% to 70% (with an average accuracy of 46.5%) for widefield images and 25% to 60% (with an average accuracy of 38.25%) for individual patches., Conclusions: The DDPM-based approach with pretraining is assessed to be effective at super-resolution prediction for ophthalmic pathology slides both in terms of objective and subjective measures. The proposed methodology is expected to decrease the reliance on costly slide scanners for acquiring high-quality pathology slide images, while also streamlining clinical workflow and expanding the scope of ophthalmic telepathology., Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article., (© 2023 by the American Academy of Ophthalmology.) more...

Background: Diabetic neovascular glaucoma is a secondary glaucoma that may require immediate correction of elevated intraocular pressure to control pain and protect the optic nerve. While there is a seasonal trend to glucose levels, it is unknown if a seasonal trend exists for diabetic neovascular glaucoma., Objective: This study evaluates the incidence of urgent glaucoma tube shunt implantation in diabetic neovascular glaucoma in a tertiary academic referral center in Southern California., Methods: Electronic medical records were queried for urgent glaucoma tube shunt surgery from 2014 to 2021. The number of cases were separated by month of occurrence, and average hemoglobin A1c values were calculated per month. Data were analyzed via ANOVA tests and one-tailed t-tests., Results: A total of 127 cases were identified. The months of March and April contained the most cases averaging 3 and 2.75 cases, respectively. April had statistically significant higher case numbers than that of other months ( P  = .041). ANOVA tests excluding April showed no statistically significant difference between the remaining months ( P  = .901). Average hemoglobin A1c values were highest in the months of April and March at 9.8 and 9.6%, respectively., Conclusion: Emergency glaucoma tube shunt surgery for diabetic neovascular glaucoma occurs most frequently in April. This observation may provide insight into disease prevention through diabetes management and help improve surgical operations such that staffing and resources are allocated accordingly., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.) more...

Purpose: To report a case of orbital coccidiomycosis in an otherwise healthy 11-month-old male., Observations: An 11-month-old male presented to his pediatrician with parental complaints of swelling, erythema, and pain of the right orbit that increased over ten days in the absence of constitutional symptoms. The child's parents reported an earlier fall onto a carpeted floor. After four weeks of conservative treatment and a course of oral cephalexin, he developed a fever, increased erythema, and palpable enlargement of a mass posterior to the lower eyelid. Ultrasound revealed an encysted mass in the inferior orbit, suggestive of an abscess. Urgent ophthalmic referral led to incision and drainage via orbitotomy. Culture, histopathology, and serological testing were positive for Coccidioides spp.. Blood studies revealed mild anemia and thrombocytosis. There was complete resolution of symptoms after surgical drainage and several weeks of oral fluconazole., Conclusion and Importance: We describe a patient with orbital coccidiomycosis without apparent systemic involvement, following what was most likely an unrelated minor trauma. Despite being rare, orbital coccidiomycosis should be considered as a primary manifestation of infection when ocular inflammation is encountered, especially in endemic regions., Competing Interests: None of the authors have any conflict of interest., (© 2022 Published by Elsevier Inc.) more...

Background: Δ9-tetrahydrocannabinol (THC) has been shown to decreased intraocular pressure (IOP). This project aims to define the relationship between plasma THC levels and IOP in healthy adult subjects., Methods: Eleven healthy subjects received a single dose of inhaled cannabis that was self-administered in negative pressure rooms. Measurements of IOP and plasma THC levels were taken at baseline and every 30 min for 1 h and afterwards every hour for 4 h. IOP reduction and percent change in IOP over time were calculated. Linear regression models were used to measure the relationship between IOP and plasma THC levels. Two line linear regression models with F-tests were used to detect change points in the regression. Then, Pearson correlations were computed based on the change point., Results: Twenty-two eyes met inclusion criteria. The average peak percentage decrease in IOP was 16% at 60 min. Percent IOP reduction as well as total IOP reduction demonstrated a negative correlation with THC plasma levels showing r-values of -0.81 and -0.70, respectively. F -tests revealed a change point in the regression for plasma levels >20 ng/ml. For levels >20 ng/ml, the correlation coefficients changed significantly with r -values of 0.21 and 0.29 ( p < 0.01)., Conclusion: Plasma THC levels are significantly correlated with IOP reduction up to plasma levels of 20 ng/ml. Plasma levels >20 ng/ml were not correlated with further decrease in IOP. More research is needed to determine the efficacy of THC in reducing IOP for eyes with ocular hypertension and glaucoma., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Mosaed, Smith, Liu, Minckler, Fitzgerald, Grelotti, Sones, Weinreb and Marcotte.) more...

Purpose: This report aims to characterize ocular changes in a case of ocular siderosis with iron toxicity using multimodal imaging and electroretinography., Methods: A 34-year-old woman presented with ocular siderosis of the left eye following penetrating injury with an iron-containing foreign body. The patient's uncorrected visual acuities were 20/60 and 20/150 in the right and left eye, respectively, with abnormal pupillary function and presence of a cataract in the left eye. She underwent successful intraocular foreign body removal and cataract surgery with no postoperative complications. Cone contrast threshold (CCT), full-field electroretinogram, spectral-domain optical coherence tomography (OCT), and OCT angiography (OCTA) were used to characterize ocular alterations preoperatively and postoperatively., Results: CCT color vision testing showed abnormal color vision, and OCTA revealed increased vascular flow density associated with the foreign body., Conclusions: CCT color vision testing, OCTA, OCT, and full-field electroretinogram can characterize retinal changes in cases of ocular siderosis., Competing Interests: Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. more...

We report a large subconjunctival-orbital granuloma in a 51-year-old male presenting with a blind painful right eye and marked chemosis 15 months after undergoing vitrectomy and silicone oil retinal tamponade for retinal detachment with no reported intraoperative complications. Gross and histopathologic examination of the enucleated eye and episcleral tumor revealed a bosselated mass measuring 17 × 10 × 5 mm containing prominent vacuoles with surrounding epithelioid histiocytes and foreign body multinucleated giant cells. Such a large silicone-induced orbital granuloma following uncomplicated retinal surgery in a grossly intact eye has not been previously reported to the authors' knowledge. High intraocular pressure and emulsification of oil may facilitate silicone extravasation through scleral wounds after retinal surgery., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2019 by S. Karger AG, Basel.) more...

Background: Cold agglutinin disease is a rare disorder characterized by an autoimmune hemolytic anemia occurring at low temperatures. Physical examination findings, often limited to acrocyanosis, are combined with a thermal amplitude test to help establish the diagnosis. Thermal amplitude testing determines the highest temperature at which the cold agglutination will occur and is an important parameter in diagnosing cold agglutinin disease., Case Presentation: Here we describe a 57-year-old white man of German and Nicaraguan descent with known chronic cold agglutinin disease who presented to our ophthalmology clinic for evaluation of a cataract. During routine cataract surgery, the lowered temperature of the conjunctiva from intermittent flow of balanced salt solution at room temperature induced a cold agglutination reaction in conjunctival vessels easily visible under a surgical microscope., Conclusions: To the best of our knowledge, this method of demonstrating cold agglutinin disease has not been described in the literature and could easily be performed utilizing an ordinary slit lamp. This method could be used as an alternative and rapid screening method for cold agglutinin disease. more...

Purpose of the Study: Orbital meningiomas are typically benign tumors, most commonly originating from the dura of the sphenoid wing or the optic nerve sheath., Procedures: We describe an unusual case of a malignant meningioma originating from the frontal lobe that ultimately produced orbital and distant metastases., Results and Conclusions: Orbital invasion by the meningioma was preceded by multiple incomplete resections, which may have facilitated access to the orbit. The present case serves to remind clinicians that surgical resection of aggressive, recurrent frontal lobe meningiomas may facilitate subsequent penetration of surrounding structures, particularly by tumors that demonstrate bone-destructive properties. more...

Purpose: We used acoustic radiation force optical coherence elastography (ARF-OCE) to map out the elasticity of retinal layers in healthy and diseased in vivo rabbit models for the first time., Methods: A healthy rabbit eye was proptosed and imaged using ARF-OCE, by measuring the tissue deformation after an acoustic force is applied. A diseased retinal inflammation model was used to observe the contrast before and after disease formation. Retinal histologic analysis was performed to identify layers of the retina corresponding with the optical images., Results: The general trend of the retinal layer elasticity is increasing stiffness from the ganglion side to the photoreceptor side, with the stiffest layer being the sclera. In a healthy rabbit model, the mechanical properties varied from 3 to 16 kPa for the five layers that were identified via optical imaging and histology (3.09 ± 0.46, 3.82 ± 0.88, 4.53 ± 0.74, 6.59 ± 2.27, 16.11 ± 5.13 kPa). In the diseased model, we have induced optical damage in a live rabbit and observed a change in the stiffness trend in its retina., Conclusions: High sensitivity elasticity maps can be obtained using the ARF-OCE system to differentiate different retinal layers. Subtle changes in the mechanical properties during the onset of diseases, such as retinal degeneration, can be measured and aid in early clinical diagnosis. This study validates our imaging system for the characterization of retinal elasticity for the detection of retinal diseases in vivo. more...

A 34-year-old patient presented with a right orbito-facial mass since childhood, consistent with a congenital arteriovenous (AV) malformation. Prior to presentation, she had multiple incomplete surgical resections and embolizations with N-butyl acetyl acrylate and Onyx-18. The patient reported gradual, progressive vision loss shortly after Onyx-18 embolization. Five months after embolization, she presented with decreased vision, disfigurement and mechanical ptosis relating to a large subcutaneous mass affecting the medial right upper eyelid and forehead. Significant exam findings included a visual acuity of 20/400 (20/60 prior to embolization), an afferent pupillary defect, and optic disc pallor. MRI and angiography revealed a persistent AV malformation with feeders from the ophthalmic artery and an absent choroidal flush to the right eye. Pathology from surgical resection showed a significant foreign body giant cell reaction to the embolization material adjacent to the vessels. We suggest that an incomplete embolization with Onyx-18 may have caused vascular steal syndrome from the ophthalmic artery. more...

To evaluate the safety and efficacy of Trabectome after failed tube shunt surgery.Twenty patients with prior failed tube shunt surgery who underwent Trabectome alone were included. All patients had at least 3 months of follow-up. Outcomes measured included intraocular pressure (IOP), glaucoma medications, and secondary glaucoma surgeries. The success for Kaplan-Meier survival analysis is defined as IOP ≤21 mm Hg, IOP reduced by at least 20% from preoperative IOP, and no secondary glaucoma surgery.Mean preoperative IOP was 23.7 ± 6.4 mm Hg and mean number of glaucoma medications was 3.2 ± 1.5. At 12 months, IOP was reduced to 15.5 ± 3.2 mm Hg (P = 0.05) and number of medications was reduced to 2.4 ± 1.5 (P = 0.44). Survival rate at 12 months was 84% and 3 patients required additional glaucoma surgery with 15 patients reaching 12 months follow-up. Other than failure of IOP control and transient hypotony (IOP < 3 mm Hg) day 1 in 2 cases, there were no adverse events.Trabecular bypass procedures have traditionally been considered an approach appropriate for early-to-moderate glaucoma; however, our study indicates benefit in refractory glaucoma as well. Eyes that are prone to conjunctival scarring and hypertrophic wound healing, such as those who have failed tube shunt surgery, may benefit from procedures that avoid conjunctival incision such as Trabectome. This study indicates potential benefits in this patient population.Trabectome was safe and effective in reducing IOP at 1-year follow-up in patients with prior failed tube shunt surgery, but not effective in reducing medication reliance in these patients. more...

Purpose: To measure high-resolution eye-specific displacements and deformations induced within the human LC microstructure by an acute increase in IOP., Methods: Six eyes from donors aged 23 to 82 were scanned using second harmonic-generated (SHG) imaging at various levels of IOP from 10 to 50 mm Hg. An image registration technique was developed, tested, and used to find the deformation mapping between maximum intensity projection images acquired at low and elevated IOP. The mappings were analyzed to determine the magnitude and distribution of the IOP-induced displacements and deformations and contralateral similarity., Results: Images of the LC were obtained and the registration technique was successful. IOP increases produced substantial, and potentially biologically significant, levels of in-plane LC stretch and compression (reaching 10%-25% medians and 20%-30% 75th percentiles). Deformations were sometimes highly focal and concentrated in regions as small as a few pores. Regions of largest displacement, stretch, compression, and shear did not colocalize. Displacements and strains were not normally distributed. Contralateral eyes did not always have more similar responses to IOP than unrelated eyes. Under elevated IOP, some LC regions were under bi-axial stretch, others under bi-axial compression., Conclusions: We obtained eye-specific measurements of the complex effects of IOP on the LC with unprecedented resolution in uncut and unfixed human eyes. Our technique was robust to electronic and speckle noise. Elevated IOP produced substantial in-plane LC stretch and compression. Further research will explore the effects of IOP on the LC in a three-dimensional framework. more...

The main goal of surgical glaucoma treatment is to reduce the intraocular pressure. The standard procedure over the past 40 years has been trabeculectomy, first described in 1968. This procedure comes with a very high risk profile, and results in moderate long-term results at best. Tube shunt devices were introduced as an alternate means to divert fluid out of the glaucomatous eye, attempting to improve upon the poor long-term outcomes of trabeculectomy, particularly in refractory cases that had failed attempts at prior glaucoma surgeries. They are currently available in a handful of different designs and have evolved from representing a second- or third-line treatment in refractory cases, to their current standing of accepted first-line surgical intervention for many surgeons. The designs of the aqueous shunts are simple and installation involves straightforward principles of ophthalmic surgery. Recent additions to the literature, as well as the development of the Ex-PRESS Miniature Shunt, are changing the way shunts are employed in the treatment algorithm for surgical glaucoma. The outcomes of these procedures are encouraging, and support their use as first-line surgical options for the treatment of adult and juvenile glaucoma. more...

Purpose: To compare outcomes across Trabectome, iScience (canaloplasty), trabeculectomy, and aqueous shunts regarding intraocular pressure (IOP), adjunctive medications, and complications after glaucoma-only and combined glaucoma-phacoemulsification surgeries for open-angle glaucomas., Method: A literature review compares success rates, complications, efficacy, and limitations of traditional and novel glaucoma surgical procedures., Results: Trabectome and canaloplasty provide modest IOP reduction with minimal intraoperative or postoperative complications. Results of Baerveldt glaucoma implant IOP reduction are comparable to trabeculectomy, but typically this shunt requires more postoperative IOP-lowering medication to achieve a success rate comparable to trabeculectomy., Conclusion: Trabeculectomy is still the most effective IOP-lowering procedure performed today but continues to have the highest serious complication rates. Trabectome and canaloplasty are reasonable surgical therapy choices for patients in which IOPs in the mid-teens seem adequate. more...

Glaucoma represents the second leading cause of blindness worldwide. While both age and intraocular pressure (IOP) are well-recognized risk factors for this disease, the underlying pathologic process involves the accelerated death of retinal ganglion cells (RGCs) that is associated with progressive loss of vision. The loss of RGCs has been postulated to occur primarily by injury to axons in the optic nerve head (ONH) due to its anatomic features and the mechanical vulnerability of the lamina cribrosa, the specialized ONH zone comprised of collagen beams that define the channels or pores through which axon bundles exit the eye. Recent advances in multiphoton microscopy using femtosecond lasers that generate second harmonic (SH) signals from collagen allows for direct optical imaging of the lamina cribrosa. We assess the application of SH generated microscopy (SHG) to the study of the ONH, and test the general hypothesis that increasing intraocular pressure in the same eye results in the movement of ONH collagen beams leading to distortion of the lamina cribrosa channels and compression of the axon bundles. more...

Background: Aqueous shunts are employed for intraocular pressure (IOP) control in primary and secondary glaucomas that fail medical, laser, and other surgical therapies., Objectives: This review compares aqueous shunts for IOP control and safety., Search Strategy: We searched CENTRAL, MEDLINE, PubMed, EMBASE, NRR all in January 2006, LILACS to February 2004 and reference lists of included trials., Selection Criteria: We included all randomized and quasi-randomized trials in which one arm of the study involved shunts., Data Collection and Analysis: Two authors independently extracted data for included studies and a third adjudicated discrepancies. We contacted investigators for missing information. We used fixed-effect models and summarized continuous outcomes using mean differences., Main Results: We included fifteen trials with a total of 1153 participants with mixed diagnoses. Five studies reported details sufficient to verify the method of randomization but only two had adequate allocation concealment. Data collection and follow-up times were variable.Meta-analysis of two trials comparing Ahmed implant with trabeculectomy found trabeculectomy resulted in lower mean IOPs 11 to 13 months later (mean difference 3.81 mm Hg, 95% CI 1.94 to 5.69 mm Hg). Meta-analysis of two trials comparing double-plate Molteno implant with the Schocket shunt was not done due to substantial heterogeneity. One study comparing ridged with standard double-plate Molteno implants found no clinically significant differences in outcome. Two trials investigating the effectiveness of adjunctive mitomycin (MMC) with the Molteno and Ahmed implants found no evidence of benefit with MMC. Two trials that investigated surgical technique variations with the Ahmed found no benefit with partial tube ligation or excision of Tenon's capsule. One study concluded there were outcome advantages with a double versus a single-plate Molteno implant and one trial comparing the 350 mm(2) and 500 mm(2) Baerveldt shunts found no clinically significant advantage of the larger device but neither of these trials included all patients randomized. One study suggested improved clinical outcome when MMC was employed with a newly described shunt including ultrasound supporting the conclusion. One small study did not demonstrate an outcome advantage to systemic steroid use postoperatively with single-plate Molteno shunts. One study comparing endocyclophotocoagulation (ECP) with Ahmed implant in complicated glaucomas found no evidence of better IOP control with Ahmed implant over ECP., Authors' Conclusions: Relatively few randomized trials have been published on aqueous shunts and methodology and data quality among them is poor. To date there is no evidence of superiority of one shunt over another. more...

Aim: This study examines the changes in axial length (AL) after trabeculectomy and glaucoma drainage device (GDD) surgery and enabled an equation to be derived allowing prediction of AL change after filtering surgery., Methods: This was a prospective, interventional case series from the Glaucoma Service of the Doheny Eye Institute., Patient Population: One eye of 39 patients undergoing trabeculectomy and 22 undergoing Baerveldt tube shunt implantation for uncontrolled glaucoma., Intervention: These patients had AL measurements by non-contact, partial coherence interferometry preoperatively, at 1 week, 1 month, and >3 months after surgery., Main Outcome Measures: Axial length and intraocular pressure were compared at preoperative and postoperative visits. Postoperative intraocular pressure (IOP) was categorised as hypotonous (0-4 mm Hg), low (5-9), normal (10-17), and high (18 or more)., Results: There was a statistically significant reduction in IOP after 3 months of -12.8 (SD 1.5) mm Hg following trabeculectomy (p<0.001), and -10.7 (1.9) mm Hg after GDD (p<0.001). There was a statistically significant reduction in AL, which was similar after trabeculectomy and GDD at all time points (p<0.001), of -0.15 (0.03) and -0.21 (0.04) mm (1 week), -0.18 (0.02) and -0.10 (0.02) mm (1 month), and -0.16 (0.03) and -0.15 (0.03) mm (3 months). At 3 months or later the AL reduction was related to postoperative IOP and to the amount of IOP reduction (p<0.05, stepwise multiple regression). 10.2% (4/39) of trabeculectomy patients had hypotony after 3 months, with a mean AL reduction (-0.39 (0.11)) that was statistically significantly lower (p<0.01) than the other trabeculectomy eyes (-0.14 (0.15))., Conclusions: There is a small but statistically significant decrease in AL after both trabeculectomy and GDD surgery, greater in eyes that are hypotonous after surgery. The authors suggest that AL reduction can be predicted after 3 months by the formula: AL reduction (mm) = -199+0.006 x IOP reduction+0.008 x final IOP. more...

Purpose: To perform noninvasive measurements of intraocular pressure (IOP) in rats, the Tono-Pen-1 and Tono-Pen-2 were calibrated against direct manometry. Normal values and the long-term fluctuations of IOP in Lewis rats were established., Methods: For calibration, 24 eyes were cannulated and connected to a pressure transducer with a chart recorder. IOP was increased from 5 to 40 mm Hg in 5 mm Hg increments, and from 40 to 60 mm Hg in 10 mm Hg increments. After each incremental increase, IOP was measured with a Tono-Pen-1 and a Tono-Pen-2 tonometer. To determine normal IOP in Lewis rats, IOP was measured with a Tono-Pen-1 in 229 eyes of 115 rats, and a histogram of normal IOP was established. To ascertain long-term IOP fluctuations, the pressure in 52 eyes of 26 rats was measured every day between 8:30 and 9:30 AM for 7 consecutive days., Results: Plotting the mean Tono-Pen readings for each eye against the transducer IOP produced two regression formulas: y = 1.819 + 0.711 x (r2 = 0.92) for Tono-Pen-1, and y = -1.291 + 0.784 x (r2 = 0.97) for Tono-Pen-2. The normal IOP in rats was 17.30 +/- 5.25 mm Hg (90% confidence interval: 7.28 and 26.98 mm Hg for the lower and upper limits of normal IOP). There was no long-term fluctuation in IOP (P = 0.55)., Conclusions: IOP can be measured accurately in living rats with the Tono-Pen-1 or the Tono-Pen-2. more...

The aim of the study was to determine mitomycin-C (MMC) concentrations in human aqueous humour during trabeculectomy and to correlate anterior chamber concentrations with method of application. MMC was applied intra-operatively by saturating sponges, ranging in size from 2 x 2 x 5 mm to 2 x 4 x 10 mm on dry cut, with 0.5 mg/ml MMC during trabeculectomy for 3-5 minutes. Applications to episclera were made in 18 cases and to the scleral bed after scleral flap dissection in 9 cases. Aqueous samples were collected by paracentesis with a 30 gauge needle 2-7 minutes after removal of sponge and external irrigation. Aqueous MMC concentrations were determined by high-performance liquid chromatography. Aqueous MMC concentration in 27 samples ranged from below minimum detectable concentration (less than 5 ng/ml) to 120.8 ng/ml. Mean aqueous drug levels obtained when the applications were to the scleral bed were 35.65 +/- 39.17 ng/ml (range 5-120.8 ng/ml). Applications on episclera gave mean aqueous concentrations of 4.98 +/- 9.11 ng/ml (range 0-33.3 ng/ml). The difference was statistically significant (p = 0.004). There were no correlations between sponge size, time of MMC exposure and aqueous MMC level. In conclusion, MMC is detectable in aqueous humour within minutes of external application and the aqueous concentration level is higher if the application is in the scleral bed than on the episclera. Toxicity of the drug at this concentration range for corneal endothelial cells needs further investigation via in vitro and clinical studies. more...

This study reports the histological findings in human eyes after severe penetrating trauma. The findings confirm the high incidence of retinal detachment in eyes with severe penetrating injuries. The retina was detached in 32 out of the 34 eyes examined, with 27 having evidence of traction on the retina. These eyes were characterized histologically by intraocular cellular proliferation producing cyclitic, epiretinal, and retroretinal membranes. Intraocular cellular proliferation was discernible or established within 1 week of injury and typically resulted in a cyclitic membrane at about 6 weeks. Epiretinal and retroretinal membranes were found between 1 and 2 weeks after injury in eyes with a detached retina. The results indicate that a damaged lens, the admixture of lens material and vitreous, and the presence of vitreous haemorrhage were all factors promoting intravitreal fibroblastic proliferation. Vitreous surgery may be a rational method of treatment for these severely injured eyes by removing the stimulus and vitreous scaffold for intravitreal fibroblastic proliferation. From this series it would appear that vitrectomy should not be delayed beyond the second week of injury, by which time massive cellular ingrowth may already be under way. more...

Orthograde and retrograde axoplasmic transport have been studied in the optic nerve heads of 37 Macaca fascicularis eyes with normal or elevated intraocular pressure (IOP) produced by cannulation of the anterior chamber. Orthograde transport was labeled by 3H-amino acids injected intravitreally and incorporated into retinal ganglion cell proteins. Retrograde transport was studied in the same eyes by injecting horseradish peroxidase (HRP) into one or both optic tracts and dorsal lateral geniculate nuclei (dLGN). Both tracers accumulated in the lamina scleralis (LS) of eyes maintained at pressures of 25 to 150 mm. Hg for 12 to 28 hours (pressure in normal controls = 10 to 14 mm. Hg) but the HRP technique was markedly more sensitive. The degree of retrograde transport obstruction in the LS appeared to be directly proportional to both the height and the duration of elevated IOP. In one experiment, the blockades of orthograde and retrograde transport induced at 50 mm. Hg were demonstrated to be reversible. Serial reconstructions of radioautographs and peroxidase-reacted sections of the optic nerve heads demonstrated that the orthograde and retrograde transport obstructions were coincidental anatomically by light microscopy in the LS and occurred most prominently in the temporal quadrants of the nerve head. These transport obstructions occurred at moderate elevations of IOP (25 TO 50 mm. Hg) despite (1) elevated arterial PO2 levels during inhalation of 100 percent oxygen and (2) intact nerve head capillary circulation, as demonstrated by perfusion with nucleated avian erythrocytes. more...

Horseradish peroxidase has been injected into the dorsal lateral geniculate nucleus of macaque monkeys to label ganglion cells of the retina by retrograde axoplasmic transport. Displaced ganglion cells, with somata in the inner nuclear layer and dendrites in the inner plexiform layer, were detected by virtue of their filling with peroxidase-positive granules. These cells were numerous in the peripapillary region, but relatively uncommon elsewhere in the retina. more...

Fifty cases of sympathetic ophthalmia were examined histologically to determine the incidence and morphology of Dalén-Fuchs nodules. At least one well-defined Dalén-Fuchs nodule was identified in 18 (36%) of the eyes examined. Three types of lesions at the level of the retinal pigment epithelium were recognised. One type was found to consist of focal hyperplasia and aggregation of retinal pigment epithelial cells. A second type, classically referred to as Dalén-Fuchs nodules, consisted of epithelioid cells and lymphocytes covered by an intact dome of retinal pigment epithelium. The third type of lesion was characterised by degeneration of the overlying retinal pigment epithelium leading to disorganisation of the Dalén-Fuchs nodule and possible release of their contents into the subretinal space. Our study demonstrated that Dalén-Fuchs nodules in sympathetic ophthalmia vary in their morphological appearance as determined by light microscopy. more...