Reliability of the Non-contact TONO-i Tonometer Compared with the Goldmann Applanation Tonometer

Purpose@#The accuracy and agreement of intraocular pressure (IOP) measurements using a noncontact self-measuring tonometer, TONO-i, compared with the Goldmann applanation tonometer (GAT). @*Methods@#A total of 35 healthy participants and 42 primary open angle or normal tension glaucoma patients were enrolled in this study. TONO-i and GAT measurements were obtained and the mean difference in IOPs was analyzed using a paired t-test. IOP agreement was calculated using the two-way random effects model. Bland-Altman analysis and simple linear regression were used to estimate the disagreement between IOP measurements. @*Results@#The mean IOPs measured using the TONO-i and GAT were 15.9 ± 3.3 mmHg and 16.4 ± 5.1 mmHg, respectively. In glaucoma patients, the mean values measured using the TONO-i (16.7 ± 4.1 mmHg) were lower than those measured using the GAT (17.9 ± 6.1 mmHg; p < 0.001). However, there was no significant difference among the healthy participants (p = 0.273). The intraclass coefficients (95% confidence interval) for all participants, normal participants, and glaucoma patients were 0.847 (0.702-0.920), 0.882 (0.804-0.941), and 0.828 (0.742-0.887), respectively, indicating good agreement between the IOP measurements. The mean difference and limits of agreement were not statistically significant. As IOP increased, the absolute difference between the GAT and TONO-i measurements also increased. @*Conclusions@#The TONO-i, a novel tonometer, may be used reliably for IOP self-measurement and detecting IOP elevations. However, caution must be exercised because of the possibility of underestimating high IOPs.

Iris Metastasis of Non-small-cell Lung Cancer Confirmed via Aqueous Humor Cytology

Purpose@#To report an iris metastasis associated with non-small-cell lung cancer (NLC) confirmed via repeat aqueous humor cytology.Case summary: A 53-year-old female presented to our ophthalmology outpatient department with complaints of vision impairment and pain in the left eye 1 month in duration. In ophthalmologic examinations, the best-corrected visual acuities were 20/20 oculus dexter (OD) and 20/32 oculus sinister (OS). The intraocular pressures measured using standard Goldmann applanation tonometery were 12 mmHg OD and 42 mmHg OS. Slit-lamp examination revealed multiple iris nodules in the left eye. Thirteen months prior, the patient had been diagnosed with NLC and was on chemotherapy. Despite the maximal tolerated medical therapy, the intraocular pressure was not controlled. As an iris metastasis was suspected, anterior chamber paracentesis was performed for aqueous humor sampling. Cytological analysis did not reveal malignant cells. One week later, aqueous humor sampling was repeated. Malignant cells were histopathologically confirmed. Given the ocular metastasis, the oncologists changed the chemotherapy regimen. @*Conclusions@#When an NLC patient exhibits iris nodules, repeat aqueous humor cytology can confirm an iris metastasis.

Filtering Bleb Size in the Early Postoperative Period Affects the Long-term Surgical Outcome after Trabeculectomy

Purpose@#To investigate whether postoperative filtering bleb size affects the surgical outcome after trabeculectomy. @*Methods@#In this study, we retrospectively reviewed 145 medically uncontrolled glaucoma patients with intraocular pressure (IOP) values >21 mmHg before surgery and data from ≥2 years of follow-up. Postoperative IOP, filtering bleb size including extent and height, and other clinical factors were measured after trabeculectomy. We divided bleb extent into quadrants and bleb height by 0.5 intervals of corneal thickness. The main outcome measure was surgical success. We confirmed complete success when the IOP was ≤21 mmHg and decreased by >20% from baseline without medication or additional procedures. Qualified success used the same criteria but allowed for medication or additional procedures. Cases with reoperation or two consecutive IOP measurements <6 mmHg were considered failures. @*Results@#A total of 145 eyes of 145 patients was included. The average observation period was 30.8 ± 10.9 months. During multivariate Cox regression analysis, a larger extent of filtering bleb revealed significantly low hazard ratios in both complete and surgical success (0.509 and 0.494, respectively); however, there was no significant relationship between bleb height and surgical outcome. @*Conclusions@#The extent of the filtering bleb was associated with surgical outcomes of trabeculectomy in glaucoma patients.

Methodology and Rationale for Ophthalmic Examinations in the Seventh and Eighth Korea National Health and Nutrition Examination Surveys (2017–2021)

This report provides a detailed description of the methodology for ophthalmic examinations according to the Korea National Health and Nutrition Examination Survey (KNHANES) VII and VIII (from 2017 to 2021). The KNHANES is a nationwide survey which has been performed since 1998 in representatives of whole Korean population. During the KNHANES VII and VIII, in addition to the ophthalmic questionnaire, intraocular pressure measurement, visual field test, auto refractometry, axial length and optical coherence tomography measurements were included. This new survey will provide not only provide normative and pathologic ophthalmic data including intraocular pressure, refractive error, axial length, visual field and precise measurement of anterior segment, macula and optic nerve with optical coherence tomography, but also a more accurate diagnosis for major adult blindness diseases, including age-related macular degeneration, diabetic retinopathy, glaucoma, and other ocular diseases, for the national Korean population.

Methodology and Rationale for Ophthalmic Examinations in the Seventh and Eighth Korea National Health and Nutrition Examination Surveys (2017–2021)

This report provides a detailed description of the methodology for ophthalmic examinations according to the Korea National Health and Nutrition Examination Survey (KNHANES) VII and VIII (from 2017 to 2021). The KNHANES is a nationwide survey which has been performed since 1998 in representatives of whole Korean population. During the KNHANES VII and VIII, in addition to the ophthalmic questionnaire, intraocular pressure measurement, visual field test, auto refractometry, axial length and optical coherence tomography measurements were included. This new survey will provide not only provide normative and pathologic ophthalmic data including intraocular pressure, refractive error, axial length, visual field and precise measurement of anterior segment, macula and optic nerve with optical coherence tomography, but also a more accurate diagnosis for major adult blindness diseases, including age-related macular degeneration, diabetic retinopathy, glaucoma, and other ocular diseases, for the national Korean population.

Fluid Dynamics of Small Diameter Tubes Used in Membrane-tube Type Glaucoma Shunt Devices

PURPOSE: To investigate the outflow characteristics of silicone tubes with intraluminal stents used in membrane-tube (MT) type glaucoma shunt devices. METHODS: The silicone tubes used in MicroMT (internal diameter of 100 µm with a 7-0 nylon intraluminal stent) and Finetube MT (internal diameter of 200 µm with a 5-0 nylon intraluminal stent) were connected to a syringe-pump that delivered a continuous flow of distilled water at flow rates of 2, 5, 10, and 25 µL/min. The pressures and resistances of tubes were measured at a steady flow rate with full-length, half-length, and absence of intraluminal stents. RESULTS: The mean outflow resistance of the two types of tubes ranged from 3.0 ± 1.9 to 3.8 ± 1.7 mmHg/µL/min with a full-length intraluminal stent, 1.8 ± 1.1 to 2.2 ± 1.1 mmHg/µL/min with a half-length intraluminal stent, and 0.1 ± 0.0 to 0.2 ± 0.0 mmHg/µL/min without an intraluminal stent. Theoretically, for a physiologic state with a flow rate of 2 µL/min and episcleral venous pressure of 6 mmHg, the mean pressures of tubes were expected to be 13.2 ± 3.0, 10.5 ± 2.4, and 6.4 ± 0.2 mmHg in MicroMT with full-length, half-length, and absence of intraluminal stents, respectively, and 12.5 ± 3.9, 9.6 ± 2.4, and 6.2 ± 0.2 mmHg in Finetube MT with full-length, half-length, and absence of intraluminal stents, respectively. The pressure variance also decreased with intraluminal stent retraction (p < 0.01). CONCLUSIONS: The small diameter tubes of 100 and 200 µm internal diameters, with 7-0 and 5-0 nylon intraluminal stents, respectively, used in the MT-type glaucoma shunt device showed safe and effective outflow characteristics.

Peripapillary Retinal Nerve Fiber Layer Thicknesses Did Not Change in Long-term Hydroxychloroquine Users

PURPOSE: To evaluate changes in the peripapillary retinal nerve fiber layer (RNFL) thicknesses using spectral-domain optical coherence tomography (SD-OCT) in hydroxychloroquine (HCQ) users. METHODS: The medical records of HCQ users were retrospectively reviewed. In these HCQ users, an automated perimetry, fundus autofluorescence photography, and SD-OCT with peripapillary RNFL thickness measurements were performed. The peripapillary RNFL thicknesses were compared between the HCQ users and the control groups. The relationships between the RNFL thicknesses and the duration or cumulative dosage of HCQ use were analyzed. RESULTS: This study included 77 HCQ users and 20 normal controls. The mean duration of HCQ usage was 63.6 ± 38.4 months, and the cumulative dose of HCQ was 528.1 ± 3.44 g. Six patients developed HCQ retinopathy. Global and six sectoral RNFL thicknesses of the HCQ users did not significantly decrease compared to those of the normal controls. No significant correlation was found between the RNFL thickness and the duration of use or cumulative dose. The eyes of those with HCQ retinopathy had temporal peripapillary RNFL thicknesses significantly greater than that of normal controls. CONCLUSIONS: The peripapillary RNFL thicknesses did not change in the HCQ users and did not correlate with the duration of HCQ use or cumulative doses of HCQ. RNFL thickness is not a useful biomarker for the early detection of HCQ retinal toxicity.

A Case of Congenital Glaucoma in Associated with Nail-patella Syndrome

PURPOSE: To report a case of congenital glaucoma associated with nail-patella syndrome. CASE SUMMARY: A 20-day-old female was referred to our clinic for bilateral intraocular pressure (IOP) elevation and treatment of corneal opacities. Her IOP was 25 mmHg and 30 mmHg in the right and left eyes, respectively. After a diagnosis of congenital glaucoma, bilateral trabeculotomy was performed under general anesthesia. On the first postoperative day, the IOP was 12 mmHg in the right eye and 10 mmHg in the left eye, and remained stable thereafter. The infant was the second of fraternal twins (birth weight of 2.42 kg) and had no family history of any particular disease. During the regular checkup, she was referred to an orthopedic clinic for disorders of the elbow and knee. She presented with a dystrophic thumbnail, patella hypoplasia, elbow hypoplasia, and bilateral triangular protrusions of the lateral iliac crest (iliac horn). Based on the above findings, typical nail-patella syndrome was diagnosed and a mutation in the LMX1B gene was detected. CONCLUSIONS: If glaucoma patients have nail deformities or musculoskeletal abnormalities, nail-patella syndrome should be suspected and a multidisciplinary approach should be conducted.

Risk Factors of Secondary Glaucoma after Congenital Cataract Surgery in Korean Patients

PURPOSE: To assess the risk of development of secondary glaucoma after congenital cataract surgery using a long-term follow-up study. METHODS: In total, 148 eyes of 91 patients who underwent congenital cataract surgery at our hospital or other hospitals were included in a retrospective chart review. A diagnosis of secondary glaucoma was made if the intraocular pressure (IOP) exceeded 21 mmHg and the corneal diameter, axial length, or the cup-to-disc ratio increased, or surgery was performed to control the IOP. To analyze the clinical features and risk factors of secondary glaucoma, we evaluated the mean age at cataract surgery, binocularity, presence of a nuclear cataract, methods of cataract surgery, presence of an intraocular lens (IOL), duration of diagnosis of secondary glaucoma after cataract surgery, duration of follow-up, recent best-corrected visual acuity, and refractive errors. RESULTS: Thirty-five eyes (23.6%) were diagnosed with secondary glaucoma as a complication of congenital cataract surgery. Of these, 11 eyes (31.4%) were treated with glaucoma surgery a mean of 3.4 times. The mean duration from congenital cataract surgery to diagnosis of glaucoma was 112.2 ± 113.1 months. Patients with aphakia had a higher risk of developing secondary glaucoma compared with patients undergoing primary IOL implantation (p = 0.001). Younger age (<3 months at surgery), a nuclear cataract, and aphakia were risk factors for the development of secondary glaucoma (p = 0.03, p = 0.006, and p < 0.001, respectively), and the risk of developing secondary glaucoma increased with secondary IOL implantation (p = 0.052). CONCLUSIONS: Secondary glaucoma after congenital cataract surgery was more common in patients with secondary IOL implantation, aphakia, a younger age (<3 months), and a nuclear cataract. Patients who underwent congenital cataract surgery had an increased risk for developing secondary glaucoma. Long-term monitoring of the IOP and optic nerve is therefore required for these patients.

Lamina Cribrosa Changes after Laser In Situ Keratomileusis in Myopic Eyes

PURPOSE: To determine deep optic nerve head structure changes after transient intraocular pressure elevation during laser in situ keratomileusis (LASIK) for myopia. METHODS: Enhanced depth imaging-optical coherence tomography was performed in each myopic eye that underwent LASIK surgery. Enhanced depth imaging-optical coherence tomography images were created at postoperative 1 day, 1 week, 2 weeks, and 1 month. Lamina cribrosa (LC) thickness, LC depth and prelaminar thickness at the superior, middle and inferior portions of the optic nerve head were measured by two investigators. RESULTS: Forty eyes in 40 patients were included in the present study. During follow-up, there were no significant differences in prelaminar thickness or LC depth. The LC demonstrated increased thickness at postoperative 1 day at all three locations (superior, middle, and inferior) (p < 0.001, p < 0.001, p < 0.001, respectively). However, no significant changes were observed at postoperative 1 week, 2 weeks, and 1 month. CONCLUSIONS: The LC thickness could increase at 1 day after LASIK surgery. However, the thickness will gradually return to baseline morphology. Temporary intraocular pressure increase during LASIK does not appear to induce irreversible LC thickness changes.

Clinical Characteristics of Juvenile-onset Open Angle Glaucoma

PURPOSE: To demonstrate the clinical characteristics of juvenile-onset open angle glaucoma (JOAG) and to evaluate the prognostic factors for visual field (VF) progression in eyes with JOAG. METHODS: The medical records of 125 eyes of 72 patients with JOAG were analyzed retrospectively. At least four reliable VF tests were required to determine the VF progression, and the progression was defined using the modified Anderson criteria. Comparisons in clinical manifestations among groups were performed using independent t-test, and generalized estimating equations were also conducted. RESULTS: The mean follow-up duration was 94.4 ± 50.5 months. Patients with JOAG showed a male preponderance (64 %), myopia (−4.99 ± 4.01 diopters) and a severe elevation of intraocular pressure (35.6 ± 10.8 mmHg). Forty-two JOAG patients (58 %) had complained of symptoms associated with vision and pain; however, one-third presented with no definite symptoms. Fifty-seven patients were diagnosed with JOAG in both eyes, and they were significantly older (p = 0.039) and had a greater family history (p = 0.035) than patients with unilateral JOAG. The progression group exhibited a significantly higher intraocular pressure at the last visit (p = 0.023) than the non-progression group. CONCLUSIONS: Because patients with considerable JOAG had no definite symptoms, periodic eye examinations are needed. To prevent the VF's progression, JOAG patients may require more careful management of intraocular pressure.

A Case of Hyphema after Selective Laser Trabeculoplasty

PURPOSE: To report a case of hyphema after selective laser trabeculoplasty (SLT) in a patient with pseudoexfoliative glaucoma. CASE SUMMARY: A 77-year-old female was referred for elevation of intraocular pressure (IOP). Previously, she had been diagnosed with pseudoexfoliative glaucoma in the right eye and was using topical IOP-lowering agents. The best corrected visual acuity was 20/100 in the right eye and 20/40 in the left eye. IOP, measured with Goldmann applanation tonometer, was 32 mm Hg in the right eye and 20 mm Hg in the left eye. Gonioscopy revealed open-angle glaucoma with +2 trabecular meshwork pigmentation but without peripheral anterior synechiae or neovascularization. SLT was performed in the right eye. Two days later, the patient had sudden onset of blurred vision and pain in the right eye. Visual acuity was limited to light perception, and IOP was 34 mm Hg in the right eye. Slit-lamp examination revealed 1.1 mm hyphema with 4+ red blood cell count in the anterior chamber. Three weeks after the SLT, hyphema in the right eye disappeared, but IOP was measured to be 42 mm Hg. The patient underwent trabeculectomy in the right eye. CONCLUSIONS: SLT is an effective means of lowering IOP with low risk of complications. However, hyphema can rarely occur after SLT and can affect the outcome of the treatment.

A Case of Steroid Glaucoma in a Child Treated with Systemic Steroid as Graft-Versus-Host Disease

PURPOSE: To report a case of steroid-induced glaucoma in a child who was treated with systemic steroids for a long period due to graft-versus-host disease. CASE SUMMARY: A 10-year-old male was referred to our ophthalmologic clinic for examination of papilledema due to persistent headache and nausea. He was diagnosed as aplastic anemia 8 years prior and took approximately 4,000 mg of oral prednisolone for 8 years from April 2007 to April 2015 for treatment of lung graft-versus-host disease after hematopoietic stem cell transplantation. His best corrected visual acuity was 0.8 (decimal) in the right eye, 0.5 in the left eye and intraocular pressure (IOP) measured using a Goldmann applanation tonometer was 42 mm Hg in the right eye and 43 mm Hg in the left eye. His cup-to-disc ratio was 0.8 in the right eye and 0.7 in the left eye. Additionally, superior and inferior neuroretinal rim thinning was present in both eyes. Despite using IOP-lowering agents, IOP was not controlled. However, after trabeculectomy with mitomycin C in both eyes, IOP became normalized. CONCLUSIONS: In cases of pediatric patients treated with systemic steroids for a long period of time, regular observation is necessary to prevent IOP elevation and steroid-induced glaucoma.

Axial Length Correlation to Lamina Cribrosa Thickness, Prelaminar Tissue Thickness, and Anterior Laminar Displacement

PURPOSE: In this study we determined the correlation of axial length to lamina cribrosa thickness (LCT), prelaminar tissue thickness (PT), and anterior laminar displacement (ALD) in young healthy eyes. METHODS: The optic discs of 60 eyes from 30 young healthy subjects with myopia were scanned using enhanced-depth imaging spectral-domain optical coherence tomography (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany). The LCT, PT, and ALD were measured at the superior midperipheral, middle, and inferior midperipheral of the optic nerve head, respectively. A linear mixed-effects model was used to determine the relationship between the axial length and the LCT, axial length and PT as well as axial length and ALD. RESULTS: The mean, superior midperipheral, and middle LCT were not significantly correlated with axial length. Conversely, the inferior midperipheral LCT was negatively correlated with axial length (p = 0.019, beta = -7.34). There was no significant association between axial length and PT. Mean ALD was negatively correlated with axial length (p = 0.022, beta = -17.17). CONCLUSIONS: In the present study, the inferior midperipheral LCT and mean ALD were negatively correlated with axial length, but PT showed no significant association with axial length.

A Case of Ocular Siderosis with Cataract and Delayed-Onset Secondary Glaucoma

PURPOSE: We report a rare case of ocular siderosis with delayed-onset secondary glaucoma occurring 10 years after cataract and iron foreign body removal. CASE SUMMARY: A 47-year-old male who suffered an ocular injury with an iron material to his left eye 3 years prior to his initial visit was treated in our clinic for a cataract with siderosis lentis. Ten years after he underwent cataract surgery he developed secondary open-angle glaucoma. Trabecular block taken during trabeculectomy showed no iron material, however, a fibrosclerotic change was observed. CONCLUSIONS: In patients with a history of traumatic siderosis lentis, a potential risk of siderosis remains for a long period.

A Case of Cataract Surgery after Radial Keratotomy

PURPOSE: To report a patient who underwent successful cataract surgery without wound dehiscence in the eye that had undergone previous radial keratotomy by performing a clear corneal incision between previous incisions. CASE SUMMARY: A 59-year-old female visited our medical center for decreased vision. The patient underwent radial keratotomy for correction of myopia in both eyes 11 years prior. On slit-lamp examination, cataract and eight radial keratotomy incisions were found. Phacoemulsification and posterior capsule intraocular lens implantation were performed for both eyes at a one-week interval. For the right eye, a clear corneal incision was made over the previous incision scar and wound dehiscence was successfully managed by prompt corneal suturing. For the left eye, a clear corneal incision was made between the previous incision scars, and wound dehiscence did not occur. CONCLUSIONS: As radial keratotomy patients age, cataract surgery should be considered. A successful surgery was possible without wound dehiscence in an eye that had undergone previous radial keratotomy in which a clear corneal incision was made between previous incision scars.

The Correlations between Donor Endothelial Lenticule Thickness and Visual Prognosis in DSAEK

PURPOSE: To determine the correlations between donor endothelial lenticule thickness and visual prognosis in Descemet's stripping automated endothelial keratoplasty (DSAEK). METHODS: The present study included 22 patients (22 eyes), who underwent DSAEK surgery in our clinic due to endothelial decompensation. BCVA (log MAR) was compared at 1 month, 3 months and 6 months postoperatively between the thin lenticule group and thick lenticule group (> or =130 micrometer). RESULTS: The BCVA (log MAR) at 1 month postoperatively was 0.46 +/- 0.22 in the thin lenticule group, and 0.71 +/- 0.26 in the thick lenticule group, and significant statistical correlations between donor lenticule thickness and visual acuity were observed (p = 0.025). However, no significant correlations were observed at 3 months (p = 0.129) and 6 months (p = 0.141) postoperatively. CONCLUSIONS: The thin donor lenticule ( or =130 micrometer), however, there is no difference in visual acuity between the 2 groups at 3 and 6 months postoperatively.

The Relations Between Progression of Peripapillary Chorioretinal Atrophy and Progression of Normal Tension Glaucoma

PURPOSE: To evaluate the relations between progression of glaucoma in visual field and peripapillary area change in normal tension glaucoma (NTG). METHODS: We respectively evaluated 66 patients (66 eyes) with normal tension glaucoma; these patients were classified as progressive glaucoma group and non-progressive glaucoma group by visual field test. Interobserver and intraobserver agreement was evaluated for qualitative assessment. Zone beta change was measured by Image J (National Institute of Health, Bethesda, USA) by two methods. One method used paired t-test and the other method used CV (correlation of variation) to define significant progression of zone beta. RESULTS: 46 patients (46 eyes) were classified as progressive glaucoma and 20 patients (20 eyes) were classified as non-progressive glaucoma. There was no statistically significant different change of zone beta between two groups and there were no changes of zone beta over coefficient of variation (CV). CONCLUSIONS: The measurement of change of zone beta seems to be of no use in recognition of progression in normal tension glaucoma.

Signal and Noise Analysis of Indirect-Conversion Digital Radiography Detectors Using Linear-systems Transfer Theory / 의학물리

For the use of Indirect-conversion CMOS (complementary metal-oxide-semiconductor) detectors for digital x-ray radiography and their better designs, we have theoretically evaluated the spatial-frequency-dependent detective quantum efficiency (DQE) using the cascaded linear-systems transfer theory. In order to validate the developed model, the DQE was experimentally determined by the measured modulation-transfer function (MTF) and noise-power spectrum, and the estimated incident x-ray fluence under the mammography beam quality of W/Al. From the comparison between the theoretical and experimental DQEs, the overall tendencies were well agreed. Based on the developed model, we have investigated the DQEs values with respect to various design parameters of the CMOS x-ray detector such as phosphor quantum efficiency, Swank noise, photodiode quantum efficiency and the MTF of various scintillator screens. This theoretical approach is very useful tool for the understanding of the developed imaging systems as well as helpful for the better design or optimization for new development.