Comparison of intraocular lens power calculation formulas in patients with a history of acute primary angle-closure attack.

BACKGROUND: To compare the accuracy of nine intraocular lens (IOL) power calculation formulas, including three traditional formulas (SRK/T, Haigis, and Hoffer Q) and six new-generation formulas (Barrett Universal II [BUII], Hill-Radial Basis Function [RBF] 3.0, Kane, Emmetropia verifying optical [EVO], Ladas Super, and Pearl-DGS) in patients who underwent cataract surgery after acute primary angle closure (APAC). METHODS: In this retrospective cross-sectional study, 44 eyes of 44 patients (APAC) and 60 eyes of 60 patients (control) were included. We compared the mean absolute error, median absolute error (MedAE), and prediction error after surgery. Subgroup analyses were performed on whether axial length (AL) or preoperative laser peripheral iridotomy affected the postoperative refractive outcomes. RESULTS: In the APAC group, all formulas showed higher MedAE and more myopic shift than the control group (all P < 0.05). In APAC eyes with AL ≥ 22 mm, there were no differences in MedAEs according to the IOL formulas; however, in APAC eyes with AL < 22 mm, Haigis (0.49 D) showed lower MedAE than SRK/T (0.82 D) (P = 0.036) and Hill-RBF 3.0 (0.54 D) showed lower MedAE than SRK/T (0.82 D), Hoffer Q (0.75 D) or Kane (0.83 D) (P = 0.045, 0.036 and 0.027, respectively). Pearl-DGS (0.63 D) showed lower MedAE than Hoffer Q (0.75 D) and Kane (0.83 D) (P = 0.045 and 0.036, respectively). Haigis and Hill-RBF 3.0 showed the highest percentage (46.7%) of eyes with PE within ± 0.5 D in APAC eyes with AL < 22 mm. Iridectomized eyes did not show superior precision than the non-iridotomized eyes in the APAC group. CONCLUSIONS: Refractive errors in the APAC group were more myopic than those in the control group. Haigis and Hill-RBF 3.0 showed high precision in the eyes with AL < 22 mm in the APAC group.

Toxicity of simultaneous intrastromal and intracameral injection of voriconazole on corneal endothelium in a rabbit model.

PURPOSE: To investigate the toxicity of repeated simultaneous intrastromal and intracameral injections of voriconazole in corneal endothelial cells in a rabbit model. METHODS: Thirty-six eyes of 18 New Zealand white rabbits (six eyes per group) were divided into 6 groups according to the concentration of voriconazole (Group A, 0%; Group B, 0.05%; Group C, 0.1%; Group D, 0.25%; Group E, 0.5%; Group F, 1%). A combination of intrastromal and intracameral voriconazole injections were administrated to the eyes of each group three times on days 0, 3, and 7. Corneal clouding grades and central corneal thickness (CCT) were examined on days 0, 3, 7, 10, and 14. The endothelial cell counts (ECC) were measured on days 0 and 14. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed on day 14. RESULTS: Group F (1%) showed more severe corneal clouding than the other groups (Groups A-E) from day 7 (p < 0.05, respectively). There were no significant differences in CCT and ECC among the six groups at any time point (p > 0.05, respectively). SEM revealed blurring of the cell border and loss of microvilli at concentrations ≥0.25% (Groups D-F). TEM revealed microstructural changes in endothelial cells at concentrations ≥0.1% (Groups C-F), and multiple vacuoles were observed at a concentration of 1% voriconazole (Group F). CONCLUSIONS: Repeated simultaneous intrastromal and intracameral voriconazole injections at a concentration of 0.1% or higher induced microstructural endothelial damage in rabbit corneal endothelial cells.

Retinal Thickness and Its Interocular Asymmetry Between Parkinson's Disease and Drug-Induced Parkinsonism.

BACKGROUND: Drug-induced parkinsonism (DIP) is common, but diagnosis is challenging. Although dopamine transporter imaging is useful, the cost and inconvenience are problematic, and an easily accessible screening technique is needed. We aimed to determine whether optical coherence tomography (OCT) findings could differentiate DIP from Parkinson's disease (PD). METHODS: We investigated 97 de novo PD patients and 27 DIP patients using OCT and [18F] N-(3-fluoropropyl)-2b-carbon ethoxy-3b-(4-iodophenyl) nortropane (FP-CIT) positron emission tomography. We compared peripapillary retinal nerve fiber layer thickness (pRNFLT) and macular retinal thickness (mRT) between PD and DIP patients as well as interocular differences in the pRNFLT and the mRT. Asymmetric index (%) for retinal thickness (AIRT) was calculated to measure the interocular differences between pRNFLT and mRT. The correlation between AIRT and total striatal specific/non-specific binding ratio asymmetry index (SNBRAI) was investigated in PD and DIP patients. RESULTS: No significant differences in pRNFLT and mRT values were observed between PD and DIP patients (all P values > 0.090). The mean SNBRAI was significantly higher in PD than in DIP (P = 0.008) patients; however, AIRT did not differ between PD and DIP patients in pRNFLT and mRT (all P values > 0.100). SNBRAI did not correlate with AIRT of pRNFL or mRT in PD and DIP patients (all P values > 0.060). CONCLUSION: Our study showed no benefit of retinal thickness and interocular asymmetry measurements using OCT for distinguishing PD from DIP in the early stages. Additional investigations are needed for confirmation.

Border tissue morphology is associated with macular ganglion cell thickness in open-angle glaucoma.

Externally oblique border tissue (EOBT) configuration is topographically associated with glaucomatous damage in the optic nerve head. We investigated the relationship between the EOBT characteristics and macular retinal ganglion cell (RGC) thickness in patients with open-angle glaucoma (OAG). A total of 149 eyes with OAG that had an EOBT observed on optical coherence tomography exams were included. After determining the maximum EOBT length and angular location of the maximal EOBT length, we analyzed their correlation with macular ganglion cell inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thickness. The macular GCIPL and pRNFL thickness were compared based on the angular location of the longest EOBT, and their association was assessed using multivariable regression analysis. Maximum EOBT length was significantly correlated with macular GCIPL thickness, but not with pRNFL thickness. Macular GCIPL was thinnest in eyes with EOBT located in a temporal direction to the optic disc. Longer maximum EOBT and temporally elongated EOBT were independently associated with a thinner macular GCIPL in the multivariable regression analysis. These suggest that temporal elongation of the EOBT may increase the stress and strain on the RGCs derived from the macula and make RGCs more susceptible to glaucoma-inducing damage.

Motor Asymmetry and Interocular Retinal Thickness in Parkinson's Disease.

BACKGROUND: To analyze the relationship between interocular difference of retinal thickness and motor asymmetry in Parkinson's disease (PD). METHODS: Prospective case-control series analyzed 62 eyes of 31 patients with PD and 62 eyes of 31 age- and sex-matched control. Ophthalmologic examinations including optical coherence tomography (OCT) scans were performed in both groups, and in the patients with PD, motor function was evaluated on the Unified Parkinson's Disease Rating Scale part III (UPDRS-III) to determine the clinically more affected side. Peripapillary retinal nerve fiber layer thickness (pRNFLT) and macular retinal thickness (mRT) were measured in both eyes, after which the interocular asymmetry of the OCT parameters was determined. Additionally, the more and less affected sides of the UPDRS-III were evaluated using Symmetric index. RESULTS: The average and quadrant pRNFLT and mRT values between the two groups were not different, but the interocular asymmetry of the average mRT and asymmetry index of retinal thickness (AIRT) of temporal mRT were significantly higher in the PD patients than in the controls (P = 0.026 and 0.044). The sum of UPDRS-III showed a discrepancy between the more and less affected sides (P = 0.002); the calculated Symmetric index was 0.21 ± 0.19, which suggested asymmetric motor symptoms. The Symmetric index of UPDRS-III showed significant relations for interocular asymmetry of superior mRT and AIRT of average mRT (P = 0.001 and 0.008). CONCLUSION: In the PD patients, the interocular asymmetry of mRT was larger than in the controls, and the motor symptoms were asymmetric. Additionally, the interocular asymmetry of mRT showed a significant correlation with motor-symptom laterality.

Effect of Phacoemulsification on Intraocular Pressure in Healthy Subjects and Glaucoma Patients.

BACKGROUND: We investigated how cataract surgery might influence long-term intraocular pressure (IOP) change in both healthy subjects and glaucoma patients. METHODS: A retrospective analysis of patients who had had clear corneal phacoemulsification with a minimum of 12 months of follow up was performed. Glaucoma patients with medically controlled open-angle glaucoma and healthy subjects with no glaucoma were included in the analysis. The change of IOP after phacoemulsification and factors associated with postoperative IOP change were investigated. RESULTS: In total, 754 eyes of 754 patients, specifically 106 patients with glaucoma and 648 patients with no glaucoma (i.e., healthy subjects) were enrolled. The phacoemulsification effected a reduction of IOP: 1.03 ± 3.72 mmHg in healthy subjects and 1.08 ± 3.79 mmHg in glaucoma patients at postoperative 1 year (P = 0.656). There were negative coefficients of IOP until 1 year of follow up (all P < 0.001), but the IOP change gradually showed a less steeply decreasing slope (correlation coefficient: -0.993), compared with those for 1 week and 1 month of follow up (correlation coefficients: -1.893 and -1.540, respectively). In the multivariate analysis, age and preoperative IOP showed significant associations with postoperative IOP change (regression coefficients: -0.034 and 0.419 respectively, all P < 0.001). CONCLUSION: Phacoemulsification resulted in IOP reduction, which effect regressed in healthy subjects and glaucoma patients over the course of long-term follow up. Therefore, long-term monitoring of IOP change is needed. In cases of higher preoperative IOP and young patients, phacoemulsification alone is a reliable option for IOP control.

The Association of Single-Nucleotide Polymorphisms in the MMP-9 Gene with Normal Tension Glaucoma and Primary Open-Angle Glaucoma.

PURPOSE: To evaluate the association of matrix metalloproteinases (MMP)-9 gene polymorphisms with normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG) in the South Korean population. MATERIALS AND METHODS: A total of 700 South Korean subjects were recruited: 146 patients with NTG, 174 patients with POAG, and 380 healthy adults. Five single-nucleotide polymorphisms (SNPs; rs3918429, rs2274755, rs3787268, rs3918261, and rs3918270) of MMP-9 were analyzed in all subjects. The association with each disease was tested using an allelic χ2 test and p values were corrected by permutation tests with 100 000 permutations. RESULTS: Among the five SNPs, rs2274755 showed a significant association with NTG (p = 0.021). The T allele of rs2274755 had an allelic odds ratio of 1.67 (95% confidence interval, 1.12-2.50). The association remained significant after correction using permutation tests (p = 0.039). It was also significant in an association analysis for genotype frequency (p = 0.011). The SNP was predicted to be found within a splicing site and a conserved region. No SNPs analyzed were significantly associated with POAG (p > 0.05). CONCLUSIONS: The rs2274755 SNP in the MMP-9 gene was significantly associated with NTG. This supports a possible role of the MMP-9 gene in NTG pathogenesis.

Safety of Using Matrix Metalloproteinase Inhibitor in Experimental Glaucoma Filtration Surgery.

We evaluated the safety of matrix metalloproteinase (MMP) inhibitor in experimental glaucoma filtration surgery in an animal model. Fifteen New Zealand white rabbits underwent an experimental trabeculectomy and were randomly allocated into 3 groups according to the adjuvant agent: no treatment group (n = 5), 0.02% mitomycin C (MMC) soaking group (n = 5), and MMP inhibitor (ilomastat) subconjunctival injection group (n = 5). Slit lamp examination with Seidel testing, pachymetry, and specular microscopy was performed preoperatively and postoperatively. The conjunctiva and ciliary body toxicity were evaluated with scores according to the pathologic grading systems. Electron microscopy was used to examine the structural changes in cornea, conjunctiva, and ciliary body. In the ilomastat-treated group, there was no statistically significant change in central corneal thickness preoperatively and at 28 days postoperatively (P = 0.655). There were also no significant changes in specular microscopy findings over the duration of the study in the ilomastat-treated group. The conjunctival toxicity score was 1 in the control group, 1.5 in the ilomastat-treated group, and 2 in the MMC-treated group. When assessing ciliary body toxicity scores, the ilomastat-treated group score was 0.5 and the MMC-treated group score was 1.5. Transmission electron microscopy did not show structural changes in the cornea and ciliary body whereas the structural changes were noticed in MMC group. A single subconjunctival injection of MMP inhibitor during the experimental trabeculectomy showed a less toxic affect in the rabbit cornea, conjunctiva, and ciliary body compared to MMC.

Long-term intraocular pressure changes after intravitreal injection of bevacizumab.

PURPOSE: To assess the long-term intraocular pressure (IOP) changes after the intravitreal injection of bevacizumab (Avastin; Genentech, Inc., South San Francisco, CA) for treatment of age-related macular degeneration (AMD) and diabetic macular edema (DME) patients and evaluate the correlation factors. MATERIAL AND METHODS: Patients with neovascular AMD or DME underwent treat-and-extended anti-VEGF regimen in one eye and followed more than 12 months were enrolled in this study. We set three criteria of IOP elevation: (1) the IOP of the treated eye increased above the contralateral eye for at least two consecutive visits; (2) the IOP of the treated eye increased above the pre-injection IOP for at least two consecutive visits; (3) and the IOP of the treated eye increased more than 5 mmHg above the baseline IOP for at least two consecutive visits. We used mixed model univariate and multivariate analysis to assess the association between IOP elevation and independent parameters including age, sex, lens status, the number of injections, and underlying disease. RESULTS: In total 152 patients, 83 patients with AMD and 69 patients with DME, were included in this study. Mean follow-up time was 18.7 months, with a maximum of 50 months. In IOP elevation, 54 eyes (35.6%) showed an IOP increase above that of the contralateral eye (criteria 1), 50 eyes (33.4%) showed an IOP increase above the baseline IOP (criteria 2), and an IOP increase greater than 5 mmHg above the baseline IOP observed in nine eyes (5.9%) (criteria 3). In the univariate analysis, lens status and total number of injections were statistically significant for criteria 2 and 3 (all ps < 0.05). However, in the multivariable analysis, only the number of intravitreal injections was statistically correlated with sustained IOP elevation for criteria 2 and 3 (p < 0.001 and p = 0.039, respectively). CONCLUSIONS: Our results suggest that under long-term monitoring, with a treat-and-extended regimen, intravitreal bevacizumab injections were associated with sustained IOP elevation. In particular, multiple intravitreal injections could be associated with sustained IOP elevation.

Evaluation of lamina cribrosa thickness and depth in ocular hypertension.

PURPOSE: To investigate the differences in thickness and depth of the lamina cribrosa (LC) between ocular hypertension (OH) patients and normal control subjects, using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT). METHODS: EDI-OCT data were obtained from the subjects in a cross-sectional analysis of data from a retrospective study. After IOP correction according to central corneal thickness (CCT), we divided the OH patients into two groups based on the corrected IOP (cIOP)--OH with lower IOP (OH-L; cIOP < 23 mmHg) and OH with higher IOP (OH-H; cIOP ≥ 23 mmHg). Comparisons of LC thickness and depth among three groups were performed. RESULTS: Seventy-four OH patients and 45 normal control subjects were included in the analysis. Among the 74 OH patients, 41 were included in the OH-L group and 33 were included in the OH-H group. LC thickness was thicker in the OH-H group compared to normal controls both in superior (P = 0.02) and inferior (P = 0.01) portions. However, no difference was found in LC depth among the three groups in any portion (P = 0.36; P = 0.44; P = 0.31, respectively). CONCLUSION: OH patients may have a thicker LC than normal control subjects, especially in OH with definite high IOP.

Visual and structural prognosis of the untreated fellow eyes of unilateral normal tension glaucoma patients.

PURPOSE: To investigate the visual and structural prognosis of untreated initial non-glaucomatous fellow eyes of unilateral normal tension glaucoma (NTG) patients. METHODS: In this retrospective observational cohort study, 50 NTG patients with unilateral visual field (VF) loss and no VF defect, retinal nerve fiber layer (RNFL) defect or neuroretinal rim (NRR) notching in the fellow eyes, and those who had initial non-glaucomatous fellow eyes untreated were included. For the fellow eyes, the development of VF defect, RNFL defect, and NRR notching was inspected retrospectively by two observers. Baseline clinical characteristics including initial intraocular pressure (IOP), central corneal thickness, and spherical equivalent (SE) were compared between glaucomatous and fellow eyes. RESULTS: During the mean follow-up period of 8.77 ± 2.92 years, five patients (10 %) developed RNFL defect and four patients (8 %) developed NRR notching in the fellow eye. Among six patients (12 %) who had developed either RNFL defect or NRR notching, only three patients (6 %) developed VF loss in 1.81, 3.09, and 9.27 years respectively. The initial IOP was significantly higher (p = 0.031), SE was more myopic (p = 0.025), and the occurrence of disc hemorrhage (p = 0.049) was significantly higher in glaucomatous eyes than that in fellow eyes. CONCLUSIONS: The incidence of glaucoma development in the fellow eye is rather low. Therefore, the initial non-glaucomatous fellow eye of the unilateral NTG patient may be observed without treatment until glaucoma develops.

Depth and area of retinal nerve fiber layer damage and visual field correlation analysis.

PURPOSE: To evaluate the relationship between the structural damage as assessed by time-domain optical coherence tomography (OCT) and functional changes in glaucoma. METHODS: In total, 190 patients with normal tension glaucoma or primary open angle glaucoma were included in this study. The thickness of retinal nerve fiber layer (RNFL) around the optic disc and the area of RNFL defect were determined using OCT scans. The relationships between the RNFL thickness or area of the defect and visual field (VF) indices were assessed using the Lowess function, regression analysis and partial Spearman correlation. The differences between these associations depending on the stage of VF damage were further analyzed. Age, optic disc size, refraction, central corneal thickness and the presence of systemic disease were corrected for in order to exclude confounding factors. RESULTS: A logarithmic scale of RNFL thickness showed a negative linear relationship with VF indices. The area of the RNFL defect showed a weak correlation with the pattern of standard deviation, whereas the remnant RNFL thickness was moderately correlated with the pattern of standard deviation (partial Spearman correlation coefficient, 0.39, -0.47, respectively; p < 0.0001). Many outliers were detected in the Lowess-plotted graphs. Multiplication of the area and the inverted RNFL thickness showed a moderately correlated logarithmic relationship with the VF indices (partial Spearman correlation coefficient, 0.46; 95% confidence interval, 0.34 to 0.57; p < 0.0001). In the severe stage of VF damage, correlation between the area of the RNFL defect and mean deviation was significantly greater than in other stages (partial Spearman correlation coefficient, -0.66; p = 0.02). CONCLUSIONS: The thickness of the RNFL had a negative logarithmic correlation with the VF indices and was more relevant to the VF indices than the area of the RNFL defect, as measured by OCT.

A case of fungal keratitis and onychomycosis simultaneously infected by Trichophyton species.

BACKGROUND: Fungal keratitis is difficult to treat that can result in corneal blindness requiring penetrating keratoplasty and in fungal endothalmitis. We report a case of fungal keratitis and onychomycosis simultaneously infected by Trichophyton. CASE PRESENTATION: A 77-year old male presented with ocular pain, conjunctival injection, and severe loss of vision in his left eye. His best corrected visual acuity was hand movements in the left eye, and slit-lamp examination showed a corneal ulcer with feathery margin and hypopyon. Bacterial and fungal smear/culture showed no organism, and there was no improvement in spite of treatment with topical fortified 5% cefazolin and 2% tobramycin. Trichophyton species was identified by repeated cultures. We found onychomycosis on the patient's foot, where the same fungal species were identified. Regimen was changed to topical itraconazole and systemic intravenous itraconazole. No clinical improvement was observed, so therapeutic penetrating keratoplasty and cryotherapy was done with continuation of antifungal therapy. The graft was clear at postoperative 1 month and no evidence of recurrence was found. CONCLUSION: It is important to identify the pathogen of keratitis because early identification of pathogen causing keratitis provides the appropriate treatment in early phase of keratitis. It is necessary to search for other fungal skin infections such as onychomycosis and athelete's foot considering the fungal keratitis following skin infection. In addition, fungal skin infection including onychomycosis should be treated for prevention of fungal keratitis as soon as possible.

Evaluation of peripapillary choroidal thickness in unilateral normal-tension glaucoma.

PURPOSE: To evaluate the association of normal-tension glaucoma and peripapillary choroidal thickness. PARTICIPANTS: Sixty-one patients with normal-tension glaucoma in one eye. METHODS: Spectral domain optical coherence tomography (SD-OCT) scans were obtained to estimate peripapillary choroidal thickness in a group of unilateral normal-tension glaucoma patients. The average peripapillary choroidal thicknesses of the glaucomatous eye and the nonglaucomatous eye of each patient were compared, and the choroidal thickness underlying the retinal nerve fiber layer defect in the glaucomatous eye was compared with the choroidal thickness of a compatible position in the contralateral normal eye. The associations of peripapillary choroidal thickness with independent parameters including the presence of glaucoma, age, sex, refractive error, axial length, central corneal thickness, intraocular pressure, visual field mean deviation, visual field pattern standard deviation, and systemic disease were assessed with mixed model univariate and multivariate analyses. RESULTS: The average peripapillary choroidal thickness was not statistically significantly different in the glaucomatous and nonglaucomatous eyes of the patients (P = 0.52). There was no definite difference between the choroidal thickness underlying the retinal nerve fiber layer defect in the glaucomatous eye and the choroidal thickness of a compatible position in the contralateral normal eye, indicating that there was no correlation of the retinal nerve fiber layer with choroidal thickness. Age (P = 0.004) and axial length (P ≤ 0.0001) were negatively associated with peripapillary choroidal thickness. CONCLUSIONS: In unilateral normal tension glaucoma, there was no significant intereye difference in choroidal thickness measured with SD-OCT. The structural features of the choroid may not be associated with normal-tension glaucoma.

The effect of bevacizumab on the outcome of trabeculectomy with 5-Fluorouracil.

BACKGROUND: To evaluate the effect of bevacizumab in trabeculectomies with 5-fluorouracil (5-FU). METHODS: Thirty-six patients with uncontrolled glaucoma were included. Twelve patients underwent trabeculectomies with intracameral and subconjunctival injections of bevacizumab (1.25 mg/0.05 mL) and subconjunctival injections of 5-FU (5.0 mg/0.5 mL). The control group underwent trabeculectomies with subconjunctival injections of only 5-FU (5.0 mg/0.5 mL). The outcome measures, including best-corrected visual acuity, intraocular pressure (IOP), number of IOP-lowering medications, the assessment of bleb, and surgical complications, were evaluated until postoperative 24 months. RESULTS: At each follow-up visit, there were no statistically significant differences between the 2 groups with regard to all outcome measures (P>0.05). The cumulative probabilities of surgical success were 50% and 58.33% in trabeculectomy with bevacizumab and 5-FU and in trabeculectomy with 5-FU, respectively (P=0.68, log-rank test). CONCLUSIONS: Bevacizumab may not exert significant additive effects in trabeculectomy when administered in conjunction with 5-FU.

A clinical and molecular genetics study of primary congenital glaucoma in South Korea.

OBJECTIVES: To investigate the clinical manifestations associated with the mutation spectrums of the human cytochrome P450 (CYP1B1) and myocilin (MYOC) genes in South Korean patients with primary congenital glaucoma (PCG). METHODS: Eighty-five unrelated PCG patients and their family members of South Korean origin were screened for mutations in the CYP1B1 and MYOC genes by sequencing with the PCR. We analysed phenotypes related to the presence, number and types of CYP1B1 mutations. In addition, the phenotype associated with the MYOC gene mutations was evaluated. RESULTS: There was no statistically significant difference in clinical studies between PCG patients with CYP1B1 mutations (N=63) and those without mutations (N=22), although the mutation group manifested disease earlier, with greater severity, and frequency in both eyes (p>0.05). However, the response to treatments was statistically different between groups and tended to be poor according to the number of mutant alleles (p=0.000, 0.0017). Patients with MYOC mutations (N=2) showed various phenotypic features. CONCLUSIONS: No consistent correlation was observed between the initial clinical manifestations and the CYP1B1 genotype. However, the response to treatment was associated with the CYP1B1 mutant alleles. This is the first report discussing the phenotypes of South Korean PCG patients associated with CYP1B1 mutations.

Comparative study of encapsulated blebs following Ahmed glaucoma valve implantation and trabeculectomy with mitomycin-C.

PURPOSE: To compare the histopathologic and morphologic findings of encapsulated blebs following Ahmed glaucoma valve implantation and primary standard trabeculectomy with mitomycin-C. METHODS: We reviewed the records of patients with otherwise uncontrollable glaucoma who had undergone Ahmed glaucoma valve implantation or trabeculectomy with mitomycin-C. Five eyes that underwent Ahmed valve implantation and three eyes that underwent trabeculectomy needed surgical revision of the initial surgery due to encapsulated bleb development with total loss of function. The surgically removed encapsulated blebs were analyzed macroscopically and microscopically. RESULTS: Removal of the encapsulated bleb was performed at a mean follow-up time of 26.6 ± 19.4 weeks in the Ahmed valve implantation group and 12.0 ± 11.4 weeks in the trabeculectomy group. The fibrotic wall of the encapsulated blebs had an overall thickness of 2.48 ± 0.42 mm in the Ahmed valve implantation group and 1.62 ± 0.37 mm in the trabeculectomy group. Macroscopically, the coconut flesh-like smooth surface was split into two layers, and the wall of the capsule was thicker in the Ahmed valve implantation group than in the trabeculectomy group. Histopathologically, the fibrotic capsule was composed of an inner fibrodegenerative layer and an outer fibrovascular layer, and there were no histopathological differences between the two groups. CONCLUSIONS: The fibrotic capsule wall was thicker in the Ahmed valve group, but there were no differences in histological findings between the two groups.

The distribution of intraocular pressure in urban and in rural populations: the Namil study in South Korea.

PURPOSE: To evaluate the intraocular pressure (IOP) distribution and its regional association in the South Korean population. DESIGN: Cross-sectional, epidemiologic study. METHODS: All participants underwent interview and the following ocular examinations: visual acuity measurement, autorefraction, pachymetry, anterior segment evaluation, slit-lamp examination, Goldmann applanation tonometry, binocular optic disc evaluation, fundus photography, and visual field test. Patients with ocular diseases other than mild senile cataract or with history of ocular surgery were excluded. RESULTS: A total of 3191 subjects residing in urban and rural areas were recruited. Mean IOP of patients from the urban area was significantly higher than that of those from the rural area (14.45 ± 2.67 mm Hg vs 13.53 ± 2.76 mm Hg, P < .05). There was regional difference of mean IOP, even after controlling for different demographic factors in the 2 areas (P < .05). Average IOP in the right eye of the investigated sample of South Korean population was 14.10 ± 2.74 mm Hg. Multiple regression analysis showed positive correlation between mean IOP and central corneal thickness, vertical cup-to-disc ratio, history of hypertension, smoking, and female sex, whereas IOP tended to decrease by approximately 0.2 mm Hg when age increased by 10 years. CONCLUSIONS: This is the first population-based epidemiologic study measuring IOP in the South Korean population. Mean IOP of the urban area was found to be significantly higher than the corresponding value of the rural area. Therefore, the regional difference, as well as other various factors, has to be considered in epidemiologic study of the distribution of IOP.