Biometric Characteristics in Eyes with Pseudoexfoliation Syndrome and Eyes with Acute Angle Closure

Purpose@#To investigate the biometric characteristics of eyes with pseudoexfoliation syndrome (PEX) according to the anterior chamber depth (ACD) by comparing them to patients with acute angle closure (AAC) and a control group. @*Methods@#A total of 130 eyes of 121 subjects (PEX, 49 eyes; AAC, 28 eyes; and control, 53 eyes) were included in the study. Axial length (AL), ACD, and lens thickness (LT) were measured with an IOL Master® 700 (Carl Zeiss Meditec, Jena, Germany). The total PEX (PXall) group was divided into a PEX with deep ACD group (PXd) and a shallow ACD group (PXs) based on an ACD of 2.70 mm. We compared the biometric results among the PXall, PXd, PXs, AAC, and control groups. @*Results@#There was no significant difference in AL between the PXall and control groups; however, the PXall group had a shallower ACD and thicker lenses. After dividing the PXall group into two groups based on ACD, the PXd group showed no difference in LT compared to the control group (p = 0.113). The LT of the PXs group was thicker than those of the PXd and control groups (p < 0.001 and p < 0.001, respectively). The PXs group had longer ALs than the AAC group (p = 0.025); however, there was no difference in LT or in the ratio of LT to AL (p = 0.222 and p = 0.076, respectively). @*Conclusions@#The biometric characteristics were different in eyes with PEX based on ACD. PEX patients with deep ACDs showed no difference in biometry compared to the control group; however, PEX patients with shallow ACDs showed characteristics of a thick LT, similar to AAC patients. There was no difference in the ratio of LT to AL among groups.

Availability of Cycloplegic Refraction in Children and Adolescents

PURPOSE: To compare non-cycloplegic and cycloplegic refractive errors and evaluate the utility of cycloplegia in Korean children and young adolescents.METHODS: An anterospective study including 406 outpatients was conducted from September 2015 to December 2017. Pre and post-cycloplegic refractive errors for both eyes were measured using Ocucyclo® and Mydrin P® with an auto-refractor. Patients were divided into different groups according to age: group 1 (< 4 years), group 2 (4–6 years), group 3 (6–8 years), group 4 (8–10 years) and group 5 (< 20 years).RESULTS: A total of 203 patients were studied. Standard deviation (sphere post-pre) was 1.26 ± 1.02 diopters significant in all age groups (p < 0.05). The mean difference decreased with increasing age (r = 0.207, p < 0.05), however, 9% of group with age greater than 10 years old still had manifest refraction-cycloplegic refraction (MR-CR) difference greater than 2 diopters. There were no significant cylindrical or axial component value difference before and after cycloplegia (p = 0.071). Significantly greater MR-CR differences were observed in hypermetropes ≥ 6 years old and myopes ≤8 years old (p < 0.05). The prevalence of pre-cycloplegic eyes with anisometria was 22.6% and 32.6%, a total of 7.39% regressed after cycloplegia (p > 0.05).CONCLUSIONS: After CR hyperopic shift was observed in all age groups. In patients with age greater than 10 years old, although statistically not significant, anisometropia and pseudomyopia still existed. Thus cycloplegic refraction should be performed in young adolescent to precisely measure and correct refractive error and avoid overcorrection.

Comparison of Central Corneal Thickness Measurements between Noncontact Specular Microscopy and Ultrasound Pachymetry

PURPOSE: We compared and analyzed central corneal thickness (CCT) measurements according to the corneal thickness obtained with noncontact specular microscopy (NCSM) and ultrasound pachymetry (USP). METHODS: CCT was measured in the order of NCSM and USP by a single optometrist in 120 eyes of 120 healthy subjects. The measurements were compared between the devices and the measurement agreements and correlations between the devices were analyzed. To determine if the measurements differed depending on the thickness of the cornea, the patients were divided into three tertile groups from the thinnest patient by CCT measurement using USP, and then the differences in CCT measured by the two devices were analyzed. RESULTS: The CCT measurements using NCSM and USP were 548.25 ± 4.64 µm and 533.09 ± 35.96 µm, respectively. NCSM measurements were found to be thicker, showing statistically significant differences between the measurements (p < 0.001). The two examinations showed a high degree of correlation (r = 0.878; p < 0.01). In the three groups, the differences in CCT measurements between NCSM and USP were 12.93 ± 21.88 µm, 16.85 ± 15.89 µm, and 15.70 ± 20.46 µm, respectively, but the differences between the three groups were not statistically significant (p = 0.655). CONCLUSIONS: Our results show that although the differences in CCT measurements using NCSM and USP were consistent regardless of the corneal thickness, the CCT measurements by NCSM and USP were highly correlated.

The Association of Renal Function with Diabetic Retinopathy Complications

PURPOSE: We investigated systemic risk factors for clinically significant macula edema (CSME) within 1 year after pan-retinal photocoagulation in patients with proliferative diabetic retinopathy. METHODS: A retrospective chart review was performed on 171 patients who received pan-retinal photocoagulation at our hospital from January 2010 to December 2016. The patients were divided into Group Ⅰ with CSME (85 eyes) and Group II without CSME (86 eyes). The associations between presence of CSME and glycated hemoglobin (HbA1c), duration of diabetes, systolic and diastolic blood pressure (BP), body mass index (BMI), lipid status, sex, and estimated glomerular filtration rate (eGFR) were evaluated. RESULTS: In the present study of 171 patients, there was no significant difference in age and gender distribution between the two groups. Duration of diabetes, total serum cholesterol, serum low density lipoprotein, HbA1c, and eGFR were significantly higher in patients with CSME (p < 0.05). Serum high-density lipoprotein, triglycerides, BMI, and systolic and diastolic BP showed no correlation with CSME. Multiple logistic regression analysis showed that total serum cholesterol and HbA1c values had significantly high odds of developing CSME. CONCLUSIONS: HbA1c, total serum cholesterol, and eGFR are important risk factors associated with CSME in patients with proliferative diabetic retinopathy secondary to pan-retinal photocoagulation. Thus, early detection of these risk factors and their control have significant roles in preventing the development and progression of maculopathy and thereby preventing severe visual loss.

Prognostic Factors of Neovascular Glaucoma in Eyes with Treated Proliferative Diabetic Retinopathy

PURPOSE: To evaluate the factors that are significant in progression to neovascular glaucoma in patients with proliferative diabetic retinopathy. METHODS: In this retrospective analysis, we reviewed the medical records of 52 patients who were first diagnosed with proliferative diabetic retinopathy from March 2014 to March 2016. We compared diabetes mellitus period, HbA1c, chronic diseases such as hypertension, hyperlipidemia, and kidney disease, insulin treatments, blood urea nitrogen, blood creatinine, glomerular filtration rate, urine albumin, dialysis, corrected visual acuity at the first visit, traction membrane sign of the retina at the first visit, vitreous hemorrhage and preretinal hemorrhage in each group and then investigated the prognostic factors of neovascular glaucoma. RESULTS: A total of 52 patients were included in the investigation, 12 patients (23.08%) were diagnosed with iris neovascularization and 4 patients (7.69%) developed neovascular glaucoma. The patients without iris neovascularization were defined as Group I, those with iris neovascularization as Group II, and those with neovascular glaucoma as Group III. The diabetes mellitus period was significantly longer in Group II (10.88 ± 7.14 years) and in Group III (11.75 ± 8.61 years) than Group I (8.30 ± 5.25 years) (p-value 0.41, 0.032, respectively). The HbA1c level was 9.59 ± 2.23 in Group II and 9.27 ± 2.54 in Group I. There was no significant difference between the two groups (p = 0.721). However, HbA1c was significantly higher in Group III (11.55 ± 0.21) than Group I (p-value 0.048). CONCLUSIONS: A long diabetes mellitus period and high HbA1c level have a significant effect on the progression to neovascular glaucoma in patients with proliferative diabetic retinopathy. This information could be useful for predicting and preventing the prognosis of patients.

Pars Plana Vitrectomy for Vitreous Hemorrhage in Coats-Type Retinitis Pigmentosa

PURPOSE: For vitreous hemorrhage induced by coats-types retinitis pigmentosa, we report a case treated with pars plana vitrectomy and endolaser photocoagulation. CASE SUMMARY: A 24-year-old male who was diagnosed with retinitis pigmentosa in both eyes 6 years earlier presented with decreased visual acuity in his left eye for the last 7 months. Corrected visual acuity was measured at 0.06 in the left eye and fundus examination revealed a vitreous hemorrhage in the left eye as well as an exudative lesion in the right eye's peripheral retina, which suggested Coats-type retinitis pigmentosa. The left eye was treated with pars plana vitrectomy. After removal of the vitreous hemorrhage, endolaser photocoagulation was performed around the peripheral exudative lesion that caused the vitreous hemorrhage. One month later, the best-corrected visual acuity increased to 0.20 in the left eye, and there was an improvement in the vitreous hemorrhage and the exudative lesion. CONCLUSIONS: Pars plana vitrectomy and endolaser can be helpful in vitreous hemorrhage induced by coats-type retinitis pigmentosa.

Comparison of Nd:YAG Capsulotomy Rates between Hydrophobic and Hydrophilic Intraocular Lenses

PURPOSE: To compare neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy rates between hydrophobic and hydrophilic intraocular lenses. METHODS: The present retrospective study enrolled patients who received cataract surgery from a single surgeon between July 2006 to December 2009. Patients included in the study were implanted with SA60AT hydrophobic spherical intraocular lenses (Alcon, Fort Worth, TX, USA, 268 eyes) or I-FLEX hydrophilic spheric intraocular lenses (i-Medical®, Ophthalmic International Heidelberg GmbH, Mannheim, Germany, 331 eyes). The Nd:YAG capsulotomy rates and best-corrected visual acuity (BCVA) were compared between the two groups for 2 years after the operation. RESULTS: The mean follow-up period was 23.5 months and 22.6 months and the mean age was 68.6 years and 70.3 years in the SA60AT and I-FLEX groups, respectively. Follow-up periods were longer in the SA60AT group (p = 0.035), but ages were not significantly different between the two groups (p = 0.367). Nd:YAG laser capsulotomy rates were 6.3% in the SA60AT group and 11.2% in the I-FLEX group. Nd:YAG laser capsulotomy rates were significantly higher in the I-FLEX group (p = 0.020). BCVA before and after the Nd:YAG laser capsulotomy was not significantly different. CONCLUSIONS: Nd:YAG laser capsulotomy rates were higher in the I-FLEX hydrophilic spheric intraocular lens group than in the SA60AT hydrophilic spheric intraocular lens group. Adhesion between capsular bag and intraocular lens by bioadhesive character of hydrophobic acryl intraocular lens may contribute to the prevention of lens epithelial migration and posterior capsule opacification.

Comparison of Nd:YAG Capsulotomy Rates between Hydrophobic and Hydrophilic Intraocular Lenses

PURPOSE: To compare neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy rates between hydrophobic and hydrophilic intraocular lenses. METHODS: The present retrospective study enrolled patients who received cataract surgery from a single surgeon between July 2006 to December 2009. Patients included in the study were implanted with SA60AT hydrophobic spherical intraocular lenses (Alcon, Fort Worth, TX, USA, 268 eyes) or I-FLEX hydrophilic spheric intraocular lenses (i-Medical®, Ophthalmic International Heidelberg GmbH, Mannheim, Germany, 331 eyes). The Nd:YAG capsulotomy rates and best-corrected visual acuity (BCVA) were compared between the two groups for 2 years after the operation. RESULTS: The mean follow-up period was 23.5 months and 22.6 months and the mean age was 68.6 years and 70.3 years in the SA60AT and I-FLEX groups, respectively. Follow-up periods were longer in the SA60AT group (p = 0.035), but ages were not significantly different between the two groups (p = 0.367). Nd:YAG laser capsulotomy rates were 6.3% in the SA60AT group and 11.2% in the I-FLEX group. Nd:YAG laser capsulotomy rates were significantly higher in the I-FLEX group (p = 0.020). BCVA before and after the Nd:YAG laser capsulotomy was not significantly different. CONCLUSIONS: Nd:YAG laser capsulotomy rates were higher in the I-FLEX hydrophilic spheric intraocular lens group than in the SA60AT hydrophilic spheric intraocular lens group. Adhesion between capsular bag and intraocular lens by bioadhesive character of hydrophobic acryl intraocular lens may contribute to the prevention of lens epithelial migration and posterior capsule opacification.

The Surgical Outcome and Stereopsis between Pseudodivergence Excess Type and Convergence Insufficiency Type

PURPOSE: To compare the surgical outcomes and stereopsis between pseudodivergence excess type and convergence insufficiency type in intermittent exotropia. METHODS: In a retrospective comparative analysis of 42 eyes, 18 eyes that were of the convergence insufficiency type (group 1) and 24 eyes that were or the pseudodivergence excess type (group 2) were analyzed. Recession-resection was performed in the same eye. Success was defined to be within ±8 PD after 12 months postoperatively; more than ±8 PD was defined as recurrence. Stereopsis was measured by the Titmus test. RESULTS: After the patch test, the mean preoperative near angle in group 1 was 35.56 ± 6.62 PD and the far angle was 23.06 ± 6.22 PD. In group 2, the mean preoperative near angle was 26.92 ± 6.30 PD and the far angle was 28.29 ± 7.41 PD. The group 1 postoperative (12 months) mean near angle was 6.89 ± 8.46 PD and the far angle was 6.11 ± 7.90 PD. In group 2, the mean postoperative near angle was 1.75 ± 2.85 PD and the far angle was 3.42 ± 3.98 PD. The success rate of group 1 was 50% and the success rate of group 2 was 83.3%. The success rate of both group were statistically significant differences (p = 0.021). The postoperative (12 months) mean of near stereopsis for group 1 was 588 ± 1,124 seconds, and group 2 was 101.25 ± 102 seconds. There were no statistically differences in postoperative (12 months) stereopsis. CONCLUSIONS: The success rate of the pseudodivergence excess type was significantly higher than in the convergence insufficiency type.

Diagnostic Availability of Blind Spot Mapping for Ocular Torsion

PURPOSE: To evaluate diagnostic the usefulness of blind spot mapping in measuring ocular torsion changes and to investigate the correlations of inferior oblique muscle overaction (IOOA) and excyclotorsion measurements using fundus photographs and blind spot mapping in patients with secondary IOOA. METHODS: Eleven patients (12 eyes; IOOA group) diagnosed with secondary IOOA were evaluated for ocular movement, fundus photograph and Humphrey standard automated perimetry, and 10 patients (20 eyes; control group) were subjected to the same tests. An ocular movement examination was performed to evaluate IOOA, and fundus photograph and Humphrey standard automated perimetry were used to measure the ocular torsion. Inferior oblique myectomy or recession was performed along with horizontal strabismus surgery, and preoperative and postoperative IOOA and ocular torsion measurements were compared between the groups. RESULTS: In the IOOA group after surgery, the IOOA decreased from +2.42 ± 0.63 to +0.50 ± 0.52, the ocular torsion decreased from +14.15 ± 3.60° to +7.47 ± 1.65° (p < 0.001) on fundus photographs, and from +12.19 ± 1.62° to +9.69 ± 1.75° (p = 0.061) in Humphrey standard automated perimetry. The control group showed a mean ocular torsion of 7.44 ± 1.62° on fundus photographs and +7.24 ± 1.28° on Humphrey standard automated perimetry. CONCLUSIONS: The usefulness of blind spot mapping when the ocular torsion was measured in IOOA patients was considered low, due to the weak correlation between IOOA and extorsion; preoperative and postoperative ocular torsion amount values were not significantly different.

Comparison of Postoperative Exodrift after First Unilateral and Second Contralateral Lateral Rectus Recession in Recurrent Exotropia

PURPOSE: To compare postoperative exodrift of the first unilateral lateral rectus (ULR) muscle recession with the exodrift of the second contralateral ULR muscle recession in patients with recurrent small-angle exotropia (XT). METHODS: We evaluated the results of a second ULR muscle recession in 19 patients with recurrent XT with deviation angles under 25 prism diopter (PD), following a first procedure of ULR muscle recession for small-angle XT. Recession of the lateral rectus muscle ranged from 8 to 9 mm. The postoperative motor alignment and degree of exodrift were investigated after the first ULR muscle recession and the second ULR muscle recession in the same patients. RESULTS: Observed differences in postoperative ocular alignment between the first ULR muscle recession and the second ULR muscle recession were statistically significant at follow-up periods of six months (7.84 +/- 4.43 vs. 3.89 +/- 3.47 PD), one year (9.58 +/- 4.97 vs. 5.21 +/- 4.94 PD), and at a final follow-up (21.11 +/- 2.98 vs. 7.52 +/- 4.06 PD) after surgery (p = 0.006, 0.013, and 0.000). Postoperative exodrift was statistically different between the first and second ULR muscle recessions at three to six months (2.89 +/-3.75 vs. 0.63 +/- 3.45 PD) and one year to final follow-up (11.52 +/- 5.50 vs. 2.32 +/- 3.53 PD) (p = 0.034 and 0.000). All of the first ULR muscle recession patients showed XT with deviation angles of more than 15 PD at the final follow-up. Regardless, the surgical success rate (<8 PD) after the second ULR recession was 63.16% (12 patients) among the total amount of patients with recurrent XT. CONCLUSIONS: This study shows that changes in exodrift after a second ULR muscle recession are less than changes after the first URL muscle recession among patients with recurrent XT. A second ULR muscle recession may be a useful surgery for small-angle XT patients with deviation angles of 25 PD or less after a first ULR muscle recession.

Macular Infarction Following Intravitreal Triamcinolone Injection for Treatment of Central Retinal Vein Occlusion

PURPOSE: To report a case of macular infarction following intravitreal triamcinolone injection for treatment of central retinal vein occlusion. CASE SUMMARY: A 75-year-old male visited our clinic for visual disturbance in his left eye and was diagnosed with macular infarction in his right eye. His medical history included type 2 diabetes, alcoholic liver cirrhosis, and hepatocellular carcinoma. After fundus examination, the patient was diagnosed with central vein occlusion with macular edema and intravitreal triamcinolone was administered to reduce edema. Within 1 week of treatment with the intravitreal injection, the patient experienced a significant decrease in visual acuity. Fluorescein angiogram showed an enlargement of the foveal avasacular zone, although optical coherence tomography (OCT) showed a decreased macular edema. Despite normalization of macular thickness on OCT and cessation of leakage on angiography, visual acuity remained at the same level during 2 months of follow-up. CONCLUSIONS: Intravitreal anti-vascular endothelial growth factor injection as well as intravitreal triamcinolone injection can cause macular ischemia which should be considered with the adopted treatment regimen for patients with ischemic risk factors.

Incidence and Risk Factors of Nd:YAG Capsulotomy in Adult Cataract Patients under 50 Years of Age According to Different Age Groups

PURPOSE: To evaluate the risk factors and incidence of neodymium-doped yttrium aluminium garnet (Nd:YAG) posterior capsulotomy due to posterior capsular opacification in adult cataract patients under 50 years of age according to different age groups. METHODS: We retrospectively studied 280 eyes that received phacoemulsification and intraocular lens implantation. The total observation period was 26.2 months on average. The subjects were divided into 3 different age groups, 20's, 30's and 40's to evaluate the incidence of posterior capsulotomy. Risk factors based on gender, age, type of cataract, type of intraocular lens (IOLs), axial length, existence of diabetes mellitus, history of ocular trauma, atopic dermatitis and refractive surgery were also investigated using statistical analysis. RESULTS: The incidence of posterior capsulotomy was 13.9% (39 of 280 eyes) and statistically significant differences were not observed based on age (7.7% in the 20's group, 13.8% in the 30's group and 14.4% in the 40's group, p=0.595). We divided subjects into 3 different groups based on axial length, below 22 mm, 22 to 26 mm and over 26 mm; posterior capsulotomy was performed in 0% (0/2), 7.2% (12/166) and 24.1% (27/112) of the patients, respectively, showing the longer axial length resulted in statistically significant increase in the incidence of posterior capsulotomy (p=0.036). The incidence of posterior capsulotomy was higher in females than in males (p=0.006). Correlations among posterior capsulotomy and type of cataract, type of IOLs and existence of diabetes mellitus, history of ocular trauma, atopic dermatitis and refractive surgery were not statistically significant. CONCLUSIONS: The difference in the incidence of Nd:YAG laser posterior capsulotomy according to age was not statistically significant in adult cataract patients under 50 years of age. We showed that longer axial length resulted in higher risk of posterior capsulotomy.

The Surgical Outcomes of Unilateral Lateral Rectus Recession in Recurrent Intermittent Exotropia after Unilateral Recession-Resection

PURPOSE: To evaluate the surgical outcomes of unilateral lateral rectus (LR) recession on the contralateral eye for recurrent intermittent exotropia after unilateral recession-resection (R & R). METHODS: A retrospective analysis of 43 patients was performed. The patients were classified into 2 groups, 18 patients who underwent unilateral LR recession for intermittent exotropia of 18 to 20 prism diopters (PD) after unilateral R & R (reoperation group) and 25 patients who had primary unilateral LR recession (primary operation group). RESULTS: Significant differences in age, gender, refractive error, preoperative deviation, and near stereoacuity were not observed between the 2 groups (p > 0.05). The mean follow-up duration was 14.28 +/- 14.98 months in the reoperation group and 14.68 +/- 12.15 months in the primary operation group. Postoperative deviations were 1.11 +/- 3.89 PD at near distance and 2.00 +/- 4.70 PD at far distance in the reoperation group and 6.44 +/- 5.26 PD at near distance and 7.00 +/- 5.77 PD at far distance in the primary operation group on the final follow-up (p = 0.000, p = 0.004). The final surgical successful rates were 94.4% in the reoperation group and 64.0% in the primary group (p = 0.021). CONCLUSIONS: The long-term surgical results of unilateral LR recession on the contralateral eye was better in patients with recurrent intermittent exotropia of 18 to 20 PD after unilateral R & R than patients who had primary unilateral LR recession.

Dose-Effect Relationship of Unilateral Medial Rectus Resection for Recurrent Exotropia

PURPOSE: To investigate the dose-effect relationship of unilateral medial rectus resection for recurrent exotropia after bilateral lateral rectus recession. METHODS: This study comprised 39 patients who underwent unilateral medial rectus resection for recurrent exotropia under 25 PD and bilateral rectus recession for prior surgery of exotropia. The medial rectus was resected from 5.0 to 7.0 mm according to angle deviation at a distance. The postoperative deviated angle was checked at one week, 3 months and 6 months postoperatively to investigate the amount of corrected deviation per resected muscle. RESULTS: The average preoperative deviation was 21.33 +/- 2.96 PD. We resected mean 6.26 +/- 0.57 mm of the medial rectus muscle. The postoperative deviated angle was 0.82 +/- 3.47, 1.87 +/- 3.10 and 5.40 +/- 4.79 PD at 1 week, 3 months and 6 months after surgery, respectively. The corrected deviated angle per millimeter (mm) was 3.29 +/- 0.68, 3.17 +/- 0.58 and 2.75 +/- 0.89 PD at 1 week, 3 months and 6 months after surgery. There were no significant differences among the changes of postoperative deviation per millimeter according to the amount of medial rectus (MR) resection (p-value = 0.423, 0.382) The success rate was 89.75%, 92.31% and 87.18% at 1 week, 3 months and 6 months after surgery, respectively. The expected corrected angle according to the amount of resection remained constant and was 3.04-3.22 PD/mm at 3 months after surgery and 2.79-2.82 PD/mm at 6 months after surgery. CONCLUSIONS: The dose-effect per millimeter was decreased as time passed. There was no statistical difference among the corrected deviation angles per millimeter according to the amount of MR resection. We expect that the calculated dose-effect relationship may be a useful guideline for unilateral medial rectus resection for recurrent exotropia.

Traumatic Rupture of the Superior Oblique Muscle Tendon

Traumatic rupture of the superior oblique muscle is rare. We report a case of a 54-year-old man injured by the metal hook of a hanger, resulting in a rupture of the superior oblique muscle tendon. He complained of torsional diplopia when in the primary position. The distal margin of the superior oblique muscle was reattached to sclera 5 and 9 mm apart from the medial insertion of the superior rectus muscle. One week after the operation, torsional diplopia disappeared. However, a 4-prism diopter ipsilateral hypertropia was observed. Three months later, hypertropia gradually increased to 20 prism dioptors and the second operation was done to correct vertical diplopia.

Incidence and Risk Factors of Nd:YAG Capsulotomy in Adult Cataract Patients Younger than 50 Years of Age

PURPOSE: To evaluate the cumulative incidence and estimate the risk factors of Nd:YAG capsulotomy due to posterior capsular opacification in adult cataract patients younger than 50 years of age. METHODS: In the present study we retrospectively reviewed 118 consecutive eyes that received phacoemulsification and intraocular lens implantation. We analyzed the cumulative incidence of Nd:YAG posterior capsulotomy and the associated risk factors. RESULTS: The cumulative incidence of posterior capsulotomy was 4.24%, 5.08%, 8.47%, 15.25%, and 20.34% in adults younger than 50 years of age at 3 months, 6 months, 12 months, 24 months, and more than 24 months after cataract surgery, respectively. The nuclear type (p = 0.021) and the mature type (p = 0.014) cataract groups were strongly associated with an increased risk of posterior capsulotomy compared with the posterior subcapsular type. The hydrophobic and single-piece intraocular lens caused the lowest incidence of posterior capsulotomy among intraocular lenses used for cataract surgery (p = 0.028). The subgroup analysis showed no statistical significance between gender, existence of diabetic mellitus or glaucoma, intraocular lens haptic material and the risk of posterior capsulotomy (p > 0.05). CONCLUSIONS: The cumulative incidence of Nd:YAG capsulotomy was 20.34% in adults younger than 50 years of age and at more than 24 months after cataract surgery. The risk factors associated with posterior capsulotomy included nuclear and mature cataract types. Additionally, there was a difference in the incidence of posterior capsulotomy according to the type of intraocular lenses.

The Correlation of Differences in the Ocular Component Values with the Degree of Myopic Anisometropia

PURPOSE: To determine the relationship between the differences in the ocular component values with the degree of anisomyopia. METHODS: Refraction, corneal power (CP), and biometry were examined in 50 myopic adults with refractive differences (RD) over 1.50 diopters (D). Ocular components were measured by ultrasound biometry and keratometry. The correlation between the differences in the ocular component values with the degree of anisomyopia was analyzed by linear regression analysis. RESULTS: Among 50 adults with anisomyopia, 5 had RD from 1.50 to 2.99 D, 11 had RD from 3.00 to 3.99 D, 9 had RD from 4.00 to 5.99 D, 12 had RD from 6.00 to 7.99 D, 7 had RD from 8.00 to 11.99 D, and 6 had > or =12.00 D. There was no significant correlation between the ocular components (CP, crystalline lens thickness [LT], and anterior chamber depth [ACD], and the length from the cornea to the posterior surface of the lens [ACD + LT]) and the RD (p > 0.05). The RD showed a significantly positive correlation with vitreous chamber depth (VCD), and axial length (r = 0.963, p < 0.0001). CONCLUSIONS: The severity of anisomyopia was not correlated with the between-eye differences in the anterior chamber values of the eye (CP, ACD, LT, ACD + LT). The severity of anisomyopia was significantly correlated with the between-eye differences in VCD.

Distance Stereoacuity by Frisby Davis Distance Stereotest after Surgery in Intermittent Exotropic Patients

PURPOSE: To compare distance stereoacuity in patients with intermittent exotropia before and after surgery using the Frisby Davis distance stereotest (FD2), and to determine the preoperative factors that affect the postoperative distance stereoacuity. METHODS: A total of 56 patients with intermittent exotropia were examined for the present study. To determine preoperative factors that affect postoperative distance stereoacuity, age, gender, distance control, and presence of fusion were measured. The deviation angle was measured at near and at distance by using a prism cover test. Distance stereoacuity was measured with the FD2 test. RESULTS: According to the results of the FD2 test, the mean preoperative distance stereoacuity of patients was 64.7 +/- 76.1 sec of arc, and improved to 53.6 +/- 85.9 sec of arc postoperatively. The distance stereoacuity improved notably from 63.0 to 40.0 sec of arc after the successful surgery. No significant correlation was present between type of surgery, distance control, presence of fusion, and postoperative improvement of distance steroacuity. CONCLUSIONS: Decreased stereoacuity in intermittent exotropic patients improved postoperatively, and the FD2 test was valuable in evaluating the stereoacuity in intermittent exotropic patients pre- and postoperatively.

Muscle Weakening and Change of Tension According to Degree of Superior Rectus Z-Myotomy in Rabbits

PURPOSE: To identify the muscle weakening effect and the change of muscle tension according to degree of superior rectus Z-myotomy in rabbits. METHODS: After dissection of superior rectus in 15 rabbits (30 eyes), marking was done on 10 mm apart from muscle insertion. Then, Z-myotomy was done on 2 mm and 8 mm apart from muscle insertion which are two different positions on apposite sides. 25%, 50% and 75% Z-myotomy were defined as group 1 (10 eyes), group 2 (10 eyes) and group 3 (10 eyes). After Z-myotomy, the change of muscle lengthening between muscle insertion and marking, and muscle tension were measured. At 4 weeks after Z-myotomy, all parameters were re-measured. RESULTS: After Z-myotomy all markings moved posteriorly, and showed result as 10.83 +/- 0.13 mm in group 1, 11.02 +/- 0.17 mm in group 2 and 12.01 +/- 0.23 mm in group 3 respectively. Muscle tension result showed as 3.98 +/- 0.22 mm in group 1, 3.54 +/- 0.18 mm in group 2 and 2.87 +/- 0.25 mm in group 3. In comparison of three groups, group 2 and group 3 showed the significant results (p < 0.05). At 4 weeks after Z-myotomy the markings showed result as 10.55 +/- 0.14 mm, 10.85 +/- 0.20 mm, 11.91 +/- 0.14 mm respectively, and in group 2 and group 3 the significant changes were seen (p < 0.05). Muscle tensions were 4.01 +/- 0.31 mm, 3.88 +/- 0.53 mm, 3.12 +/- 0.42 mm respectively. There were significant results in group 2 and group 3 (p < 0.05). CONCLUSIONS: 75% Z-myotomy of superior rectus showed significant results in muscle weakening and decreasing muscle tension.