Artificial Tear Instillation-Induced Changes in Corneal Topography

This study aims to compare changes of corneal topography (Galilei G4) before and after the instillation of artificial tears in patients with dry eye disease (DED). Corneal topography was performed in patients 1 min before and after artificial tear instillation. Two types of artificial tears were used: 1% polysorbate 80 (PSB) and 0.5% carboxymethylcellulose (CMC). Of 135 patients, PSB and CMC were instilled in 101 and 34 eyes, respectively. The average value of Sim K increased significantly after instillation (44.07 ± 2.26 diopter (D)) compared to before (43.90 ± 2.02 D, p = 0.006) the instillation of artificial tears. Mean Sim K astigmatism was statistically increased after PSB instillation (1.48 ± 2.17 D) compared to before instillation (1.31 ± 2.10 D, p = 0.049). An axis change of astigmatism 10° or more after artificial tear instillation was found in 51.9% of patients, and 30° or more in 20.0% of patients. Increased Sim K value and significant changes in the astigmatic axis in the corneal topography were observed after instillation of artificial tears in DED patients. PSB instillation had a greater effect on corneal keratometry values than CMC instillation.

A Comprehensive Analysis of the Influence of Temperature and Humidity on Dry Eye Disease

PURPOSE

To investigate the effects of humidity and temperature on dry eye disease (DED).

METHODS

A retrospective, clinic-based study was conducted on DED patients undergoing dry eye treatment. Patients were followed up at least twice, and symptoms and signs were evaluated using the Symptoms Assessment Questionnaire in Dry Eye (SANDE) score, tear secretion, tear film breakup time (TBUT), ocular staining score, and tear osmolarity. Mean humidity and temperature values for 1 week before ocular examinations were used as the environmental exposure level. The relationship between humidity and temperature, with DED clinical parameters was analyzed in single- and multi-environmental factor models.

RESULTS

The study included 33 patients with a mean age of 53.9 ± 12.2 years. The low humidity group showed significantly higher SANDE scores (p = 0.023) and tear osmolarity (p = 0.008), and the low temperature group had higher SANDE scores (p = 0.004), ocular staining scores (p = 0.036), and tear osmolarity (p < 0.001). In the linear mixed model, single factor analysis showed that an increase in humidity resulted in decreased SANDE scores (p = 0.043), and an increase in temperature led to a decrease in SANDE score (p = 0.007), ocular staining score (p = 0.007), and tear osmolarity (p = 0.012). In the multifactor analysis, changes in humidity had no significant effect on dry eye parameters, but an increase in temperature was significantly correlated with decreased SANDE score (p = 0.026), ocular staining score (p = 0.024), and tear osmolarity (p = 0.002).

CONCLUSIONS

Lower temperature led to aggravated symptoms and signs of DED and the effect of temperature on DED was more pronounced than humidity. Tear osmolarity was the most sensitive clinical parameter to be affected by climate factors in DED patients.

A cross-sectional study of ophthalmologic examination findings in 5385 Koreans presenting with intermittent exotropia

The Korean Intermittent Exotropia Multicenter Study (KIEMS) was a retrospective, cross-sectional and multicenter study for the investigation of intermittent exotropia involved 65 strabismus specialists from 53 institutions in Korea. Purpose of this study was to present ophthalmologic findings of intermittent exotropia from the KIEMS. Consecutive patients with intermittent exotropia of ≥ 8 prism diopters (PD) at distance or near fixation were included. Best-corrected visual acuity, cycloplegic refraction data, angles of deviation at several cardinal positions, ocular dominance, fusion control, oblique muscle function, and binocular sensory outcomes were collected. A total of 5385 participants (2793 females; age 8.2 years) were included. Non-dominant eye was more myopic than the dominant eye (- 0.60 vs. - 0.47 diopters, P < 0.001). Mean exodeviation angles were 23.5 PD at distance and 25.0 PD at near fixation. Basic type (86.2%) was the most, followed by convergence insufficiency (9.4%) and divergence excess (4.4%) types. Alternating ocular dominance and good fusion control were more common at near than at distance fixation. Good stereopsis at 40 cm was observed in 49.3% in Titmus stereo test (≤ 60 arcsec) and in 71.0% in Randot stereo test (≤ 63 arcsec). Intermittent exotropia was mostly diagnosed in childhood and patients with the condition showed relatively good binocular functions. This study may provide objective findings of intermittent exotropia in a most reliable way, given that the study included a large study population and investigated comprehensive ophthalmology examinations.

Outcomes of Early Surgery in Children under Four Years Old with Large Angle Intermittent Exotropia

Purpose: To find out the significance of early surgery in children of 4 years old and under with large angle intermittent exotropia of 35 prism diopters (PD) and more by examining the results of bilateral lateral rectus recession surgery and factors influencing the surgical outcome.Methods: It was a retrospective study of patients who underwent bilateral lateral rectus muscle recession surgery between 2006 to 2016 with intermittent exotropia greater than or equal to 35 PD and who were able to follow-up for at least 2 years after surgery were divided into two groups based on age of 4 years old. The surgical motor success was defined as exodeviation less than 10 PD, esodeviation less than 8 PD. The angle of deviation, binocular function, best corrected visual acuity, and amount of corrected PD per lateral recession (PD/mm) were compared at each observation point after surgery.Results: The motor success of bilateral rectus muscle recession surgery was 85% in children of age 4 years and under, 65.5% in age over 4 years. Success rate of early surgery was 1.3 times higher in younger age group, but there was no statistical meaning. The complication of surgery after 2 years of follow up was less in younger group-the rate of recurrent exotropia was 15% in younger group, 31.3% in older group and the rate of consecutive esotropia was 0% and 3.1%, respectively. Stereoacuity after 2 years of surgery was not fall behind in younger group compared to older group.Conclusions: It is possible to obtain good surgical results by performing early surgery rather than hesitating to operate due to the younger age in patients younger than 4 years old with large angle exotropia of 35 PD and more for long-term follow up and efficient patient management.

Short-Term Therapeutic Effects of Topical Corticosteroids on Refractory Dry Eye Disease: Clinical Usefulness of Matrix Metalloproteinase 9 Testing as a Response Prediction Marker

Purpose

To compare the short-term therapeutic effects of topical corticosteroids in patients with refractory dry eye disease (DED) according to the tear matrix metalloproteinase 9 (MMP-9) point-of-care positivity.

Methods

This study was conducted on 137 patients who were referred from other eye clinics, complaining of irresponsive DED or acute DED flares despite routine treatment with topical cyclosporin or diquafosol. The patients received treatment with topical corticosteroids for 1 month. DED was evaluated by SANDE (Symptom Assessment in Dry Eye) questionnaire, tear film breakup time, ocular surface staining score, and meibomian gland dysfunction stage. The InflammaDry MMP-9 immunoassay was conducted in more symptomatic eyes of all patients. The changes in the subjective symptoms were additionally surveyed as symptom improvement score.

Results

The mean age of the patients was 57.8±13.4 years, and the tear MMP-9 positivity was 73.0%. Topical corticosteroids treatment showed significant improvement of symptoms and signs in the patients with refractory DED irrespective of the positivity of MMP-9 (each p<0.001). The changes in SANDE score and OSS, and symptom improvement score were higher in the MMP-9 positive group than in the MMP-9 negative group (p=0.002/0.010/0.011). The overall rates of subjective symptoms improvement and SANDE reduction were 73.0% and 90.6% after topical corticosteroids treatment, respectively.

Conclusion

Short-term topical corticosteroids had excellent therapeutic effects in patients with refractory DED or acute DED flares, irrespective of the tear MMP-9 level. Tear MMP-9 positivity may serve as a reliable response predictor of topical corticosteroids treatment in DED.

Electrostatic frequency reduction: A negative stiffness mechanism for measuring dissipation in a mechanical oscillator at low frequency

Broadband seismometers and gravitational wave detectors make use of mechanical resonators with a high quality factor to reduce Brownian noise. At low frequency, Brownian noise is ultimately dominated by internal friction in the suspension, which has a 1/f noise compared with the white noise arising from viscous dissipation. Internal friction is typically modeled as a frequency-dependent loss and can be challenging to measure reliably through experiment. In this work, we present the physics and experimental implementation of electrostatic frequency reduction (EFR) in a mechanical oscillator-a method to measure dissipation as a function of frequency. By applying a high voltage to two parallel capacitor plates, with the center plate being a suspended mass, an electrostatic force is created that acts as a negative stiffness mechanism to reduce the system's resonance frequency. Through EFR, the loss angle can be measured as a function of frequency by measuring amplitude decay response curves for a range of applied voltages. We present experimental measurements of the loss angle for three metal helical extension springs in the nominal frequency range 0.7-2.9 Hz at 0.2 Hz intervals, demonstrating the possibility for fine adjustment of the resonance frequency for loss angle measurements. A quality factor proportional to the resonance frequency squared was measured, an indication that internal friction and other non-viscous dissipation elements, such as electrostatic damping, were the prominent loss mechanisms in our experiments. Finally, we consider the implications of Brownian noise arising from internal friction on a low 1/f noise seismometer.

Different adverse effects of air pollutants on dry eye disease: Ozone, PM2.5, and PM10

To date, there have been no well-organized clinical studies evaluating which air pollutants affect dry eye disease (DED). In this study, we investigated changes in the clinical parameters of DED according to exposure to outdoor air pollutants, including PM_2.5 (particulate matter with an aerodynamic diameter of less than 2.5 μm), PM₁₀ (less than 10 μm), and ozone. A prospective observational study was conducted on 43 DED patients who had used the same topical eye drop treatment between 2016 and 2018 in South Korea. Ocular surface discomfort index (OSDI) score, tear film break-up time (TBUT), corneal fluorescein staining score (CFSS), and tear secretion were measured during each visit. Air pollution data of ambient PM₁₀, PM_2.5, and ozone, based on the patients' address, were obtained, and mean concentrations were computed for one day, one week, and one month before the examination. The relationships between air pollutants and DED were analyzed in single- and multi-pollutant models adjusted for demographic and clinical factors. In the multi-pollutant model, the OSDI score was positively correlated with ozone and PM_2.5 exposure [ozone: β(exposure for 1 day/1 week) = 0.328 (95% CI: 0.161-0.494)/0.494 (0.286-0.702), p < 0.001/<0.001, per 1 ppb increase; PM_2.5: β(1 day/1 week) = 0.378 (0.055-0.699)/0.397 (0.092-0.703), p = 0.022/ = 0.011, per 1 μg/m³ increase], and tear secretion decreased with increased ozone exposure [ozone: β(1 week/1 month) = -0.144 (-0.238 to -0.049)/-0.164 (-0.298 to -0.029), p = 0.003/ = 0.017, per 1 ppb increase]. Interestingly, increased PM₁₀ exposure was only associated with decreased TBUT [β(1 day/1 week/1 month) = -0.028(-0.045 to -0.011)/-0.029(-0.046 to -0.012)/-0.023(-0.034 to -0.006), p = 0.001/ = 0.001/ = 0.018, per 1 μg/m³ increase]. Tear secretion and CFSS were not associated with PM₁₀ exposure. Increased ozone and PM_2.5 exposure led to aggravated ocular discomfort, and increased PM₁₀ concentration aggravated tear film stability in patients with DED. Thus, each air pollutant may aggravate DED via different mechanisms of action.

Unexpected potential protective associations between outdoor air pollution and cataracts

Air pollution is one of the biggest public health issues, and the eye is continuously exposed to multiple outdoor air pollution. However, to date, no large-scale study has assessed the relationship between air pollutants and cataracts. We investigated associations between outdoor air pollution and cataracts in the Korean population. A population-based cross-sectional study was performed using data from the Korea National Health and Nutrition Examination Survey, including 18,622 adults more than 40 years of age. The presence of cataracts and their subtypes were evaluated by ophthalmologists. Air pollution data (levels of particulate matter, ozone, nitrogen dioxide, and sulfur dioxide) for the 2 years prior to the ocular examinations were collected from national monitoring stations. The associations of multiple air pollutants with cataracts were assessed by multivariate logistic regression analyses. Sociodemographic factors and previously known risk factors for cataracts were controlled as covariates (model 1 included sociodemographic factors, sun exposure, and behavioral factors, while model 2 further included clinical factors). Higher ozone concentrations were protectively associated with overall cataract which included all subtypes [single pollutant model: 0.003 ppm increase-model 1 (OR 0.89, p = 0.014), model 2 (OR 0.87, p = 0.011); multi-pollutant model: 0.003 ppm increase-model 1 (OR 0.80, p = 0.002), model 2 (OR 0.87, p = 0.002)]. Especially, higher ozone concentrations showed deeply protective association with nuclear cataract subtype [0.003 ppm increase-single pollutant model: model 2 (OR 0.84, p = 0.006), multi-pollutant model: model 2 (OR 0.73, p < 0.001)]. Higher tropospheric ozone concentrations showed protective associations with overall cataract and nuclear cataract subtype in the Korean population.

Sex differences in the effect of aging on dry eye disease

PURPOSE

Aging is a major risk factor in dry eye disease (DED), and understanding sexual differences is very important in biomedical research. However, there is little information about sex differences in the effect of aging on DED. We investigated sex differences in the effect of aging and other risk factors for DED.

METHODS

This study included data of 16,824 adults from the Korea National Health and Nutrition Examination Survey (2010-2012), which is a population-based cross-sectional survey. DED was defined as the presence of frequent ocular dryness or a previous diagnosis by an ophthalmologist. Basic sociodemographic factors and previously known risk factors for DED were included in the analyses. Linear regression modeling and multivariate logistic regression modeling were used to compare the sex differences in the effect of risk factors for DED; we additionally performed tests for interactions between sex and other risk factors for DED in logistic regression models.

RESULTS

In our linear regression models, the prevalence of DED symptoms in men increased with age (R=0.311, P=0.012); however, there was no association between aging and DED in women (P>0.05). Multivariate logistic regression analyses showed that aging in men was not associated with DED (DED symptoms/diagnosis: odds ratio [OR] =1.01/1.04, each P>0.05), while aging in women was protectively associated with DED (DED symptoms/diagnosis: OR =0.94/0.91, P=0.011/0.003). Previous ocular surgery was significantly associated with DED in both men and women (men/women: OR =2.45/1.77 [DED symptoms] and 3.17/2.05 [DED diagnosis], each P<0.001). Tests for interactions of sex revealed significantly different aging × sex and previous ocular surgery × sex interactions (P for interaction of sex: DED symptoms/diagnosis - 0.044/0.011 [age] and 0.012/0.006 [previous ocular surgery]).

CONCLUSION

There were distinct sex differences in the effect of aging on DED in the Korean population. DED following ocular surgery also showed sexually different patterns. Age matching and sex matching are strongly recommended in further studies about DED, especially DED following ocular surgery.

Effect of horizontal rectus surgery for the correction of intermittent exotropia on sub-A or sub-V pattern

We evaluated effect of horizontal rectus surgery on sub-A or sub-V pattern intermittent exotropia. We enrolled patients with sub-A or sub-V pattern intermittent exotropia. The sub-A pattern was diagnosed when the eyes diverged less than 10 prism diopters (PD) from upgaze to downgaze, and sub-V pattern when the divergence was 14 PD or less from downgaze to upgaze. Patients had undergone horizontal rectus surgery without vertical transposition of horizontal rectus muscle or oblique muscle weakening. The patients were divided into two groups: sub-A pattern (group A) and sub-V pattern (group V). The outcome measures were change of amount of pattern and rate of collapse of pattern postoperatively. The amount of pattern (vertical incomitance) was amount of difference in exodeviation between upgaze and downgaze. Collapse of pattern was defined as disappearance of difference in exodeviation between upgaze and downgaze. In groups A and V, preoperative amounts of pattern were 4.9 PD and 6.8 PD, respectively. A significant reduction in amount of pattern was observed in both groups throughout the follow-up period (p<0.05). At postoperative 6 months, the amounts of pattern were 1.0 PD and 1.2 PD and the extents of reduction in amount of pattern were 4.4 PD and 5.9 PD. The rates of collapse of pattern at postoperative 6 months were 77.8 and 60.0%, respectively. In the patients with sub-A or sub-V pattern exotropia, horizontal rectus surgery without vertical transposition or oblique muscle weakening can successfully collapse the pattern.

The Effect of Preoperative Occlusion Therapy on Long-term Outcome after Surgery for Early-onset Exotropia

PURPOSE

To investigate the effect of preoperative part-time occlusion therapy on long-term surgical success in early-onset exotropia.

METHODS

The medical records of patients who underwent surgery for exotropia with onset before the first year of age and who were followed for ≥3 years were reviewed. Patients were divided into two groups according to the degree of compliance with part-time occlusion therapy: the good compliance group (>50% adherence rate) and the poor compliance group (≤50% adherence rate). Surgical success was defined as orthophoria to exodeviation less than 10 prism diopters both at distance and near. The level of postoperative stereopsis was compared between the two study groups among total enrolled patients and among those with constant exotropia.

RESULTS

Of the 51 patients, 26 were assigned to the good compliance group and the remaining 25 patients to the poor compliance group. The surgical success rate was significantly higher in the good compliance group than in the poor compliance group (80.8% vs. 52.0%, p = 0.040). Among 24 constant exotropia patients (12 patients for each group), the success rate was insignificantly higher in the good compliance group than in the poor compliance group (75.0% vs. 58.3%, p = 0.448). The good compliance group had a better level of stereopsis than the poor compliance group (p = 0.045 for all 44 patients, p = 0.020 for 19 patients with constant exotropia).

CONCLUSIONS

Preoperative part-time occlusion therapy was useful for improving the surgical outcome of early-onset exotropia and postoperative stereopsis.

Outdoor Air Pollution and Pterygium in Korea

We investigated relationships between outdoor air pollution and pterygium in Korean adults. This study includes 23,276 adults in population-based cross-sectional data using the Korea National Health and Nutrition Examination Survey 2008-2011. Pterygium was assessed using slit lamp biomicroscopy. Air pollution data (humidity, particulate matter with aerodynamic diameter less than 10 μm [PM₁₀], ozone [O₃], nitrogen dioxide [NO₂], and sulfur dioxide levels [SO₂]) for 2 years preceding the ocular examinations were acquired. Associations of multiple air pollutants with pterygium or pterygium recurrence after surgery were examined using multivariate logistic models, after adjusting for several covariates. Distributed lag models were additionally used for estimating cumulative effects of air pollution on pterygium. None of air pollution factors was significantly associated with pterygium or pterygium recurrence (each P > 0.05). Distributed lag models also showed that air pollution factors were not associated with pterygium or pterygium recurrence in 0-to-2 year lags (each P > 0.05). However, primary pterygium showed a weak association with PM10 after adjusting for covariates (odds ratio [OR] 1.23; [per 5 μg/m³ PM₁₀ increase]; P = 0.023). Aging, male sex, and greater sun exposure were associated with pterygium, while higher education level and myopia were negatively associated with pterygium (each P ≤ 0.001). Male sex and myopia were negatively associated with pterygium recurrence (each P < 0.05). In conclusion, exposure to higher PM10 levels was associated with primary pterygium, although this study observed no significant association between air pollution and overall pterygium or pterygium recurrence in Korean adults.

Potential Importance of Ozone in the Association Between Outdoor Air Pollution and Dry Eye Disease in South Korea

Importance

Air pollution is an important public health concern and the ocular surface is continuously exposed to pollutants in outdoor air. Ocular surface abnormalities related to air pollution are thought to be a subtype of dry eye disease (DED). However, to date, there is no large-scale study evaluating an association between air pollution and DED that includes multiple air pollutants.

Objective

To investigate associations between outdoor air pollution and DED in a Korean population.

Design, Setting, and Participants

A population-based cross-sectional study using data on 16 824 participants in the fifth Korea National Health and Nutrition Examination Survey was conducted from January 1, 2010, to December 31, 2012. Data analysis was conducted from September 1 to 30, 2015. Dry eye disease was defined as previously diagnosed by an ophthalmologist or the presence of frequent ocular pain and discomfort. Outdoor air pollution measurements (mean annual humidity, particulate matter with aerodynamic diameter <10 µm [PM10], ozone, and nitrogen dioxide levels) were collected from 283 national monitoring stations in South Korea.

Main Outcomes and Measures

Associations of multiple air pollutants with DED were assessed from multivariable logistic regression analyses. Sociodemographic factors and previously known factors associated with DED were applied as covariates (model 1 controlled for sociodemographic factors and model 2 controlled for sociodemographic, behavioral, and clinical factors).

Results

Among 16 824 participants (7104 men and 9720 women), higher ozone levels and lower humidity levels were significantly associated with symptoms and diagnosis of DED. In model 1, an increase in ozone levels of 0.003 ppm was significantly associated with symptoms and diagnosis of DED (symptoms: odds ratio [OR], 1.16; 95% CI, 1.02-1.30; P = .04; diagnosis: OR, 1.21; 95% CI, 1.05-1.40; P = .008), while a 5% increase in humidity levels was significantly associated with decreased symptoms and diagnoses of DED (symptoms: OR, 0.87; 95% CI, 0.77-0.98; P = .03; diagnosis: OR, 0.86; 95% CI, 0.76-0.97; P = .01). In model 2, an increase in ozone levels of 0.003 ppm was significantly associated with symptoms and diagnosis of DED (symptoms: OR, 1.17; 95% CI, 1.02-1.34; P = .03; diagnosis: OR, 1.27; 95 CI, 1.09-1.48; P = .002), while a 5% increase in humidity levels was significantly associated with decreased symptoms and diagnoses of DED (symptoms: OR, 0.88; 95% CI, 0.78-0.98; P = .045; diagnosis: OR, 0.86; 95% CI, 0.76-0.97; P = .02). In model 2, an increase in nitrogen dioxide of 0.003 ppm (OR, 1.12; 95% CI, 1.02-1.23 P = .02) was also associated with diagnosis of DED. Levels of sulfur dioxide and PM10 were not associated with symptoms or diagnosis of DED in model 1 or model 2 (P > .05 for each).

Conclusions and Relevance

Higher ozone levels and lower humidity levels were associated with DED in the Korean population, while PM10 level was not associated with DED.

Acquired Brown Syndrome Treated With Traction of Superior Oblique Tendon

Brown syndrome is a rare strabismic disease characterized by a limited elevation in adduction of the eye. The lengthening/weakening of superior oblique muscle is the main way of surgical intervention for this disease. A 7-year-old boy was diagnosed as having acquired Brown syndrome in his right eye after injury in his face. We experienced successful release of this Brown syndrome through mere pulling outward of superior oblique tendon during surgical exploration. We briefly discuss why this manipulation of superior oblique tendon that we performed was successful.

The impact of intermittent exotropia and surgery for intermittent exotropia on myopic progression among early school-aged children with myopia

AIM

To investigate the relationship between myopic progression and intermittent exotropia, and the impact of surgery for exotropia on myopic progression in early school-aged children (from 7 years to 12 years of age).

METHODS

Medical records of early school-aged patients with myopia were reviewed. Patients were divided into three groups; (A) Patients with intermittent exotropia and myopia at presentation and who underwent bilateral lateral rectus muscle recession for exotropia when 7-12 years old; (B) Patients with intermittent exotropia and myopia at presentation and who were merely observed for exotropia; and (C) Patients with myopia and straight ocular alignment. Main outcome measurements were the simple rate of myopic progression per year, the preoperative and postoperative rates of refractive growth with regards to the logarithmic age model in Group A, and the rate of high myopia development at the end of the early school period.

RESULTS

The rates of myopic progression were -0.43±0.14 dioptre (D) per year in Group A, -0.49±0.17 D/year in Group B and -0.42±0.24 D/year in Group C. There was no significant difference in the rate of myopic progression among three groups. There was no significant intergroup difference in the preoperative and postoperative rates of refractive growth in Group A. There were no significant intergroup differences in the rates of high myopia development among three groups.

CONCLUSIONS

Whether patients with intermittent exotropia underwent surgical correction for intermittent exotropia did not influence the rate of myopic progression. There was no significant difference in the rate of myopic progression between patients with accompanying intermittent exotropia and myopia and those with myopia alone.

Morphologic changes in trabecular meshwork after patterned and argon laser trabeculoplasty in cats

PURPOSE

Patterned laser trabeculoplasty (PLT) was introduced as it claimed to cause less thermal damage and provide more uniform coverage of the trabecular meshwork than argon laser trabeculoplasty (ALT). The objective of this study was to investigate morphologic changes in the trabecular meshwork after PLT or ALT in cats.

MATERIALS AND METHODS

We performed ALT in the right eyes and PLT in the left eyes of 6 domestic cats. A seventh cat was assigned as a control. Two ranges of laser energy were used for PLT: supra-threshold energy of 400-450 mW in 3 cats and sub-threshold energy of 250 to 350 mW in 3 cats. Specimens were obtained at 1, 4 and 9 weeks after treatment. Structural changes in the trabecular meshwork were evaluated by light microscopy and scanning electron microscopy.

RESULTS

The trabecular meshwork after supra-threshold PLT revealed coagulative damage such as a crater-like lesion with disruption of trabecular beams in early period and extensive membranous obliteration in the late period (at 4 and 9 weeks after treatment), which were comparable to tissue changes after ALT. Sub-threshold PLT resulted in thinning of the uveal meshwork and denudation of trabecular endothelial cells whereas it did not disrupt trabecular beams. Nevertheless, following sub-threshold PLT, partial membranous coverages were observed in the trabecular meshwork in the late period.

CONCLUSIONS

When used at sub-threshold power, PLT caused less thermal damage to the trabecular meshwork than ALT. However, it did not effectively prevent late scarring of the trabecular meshwork in cats.

Self-grading effect of inferior oblique recession

PURPOSE

Inferior oblique (IO) myectomy can result in self-adjustment; the greater the preoperative hyperdeviation, the larger the postoperative correction. This study estimated the effect of IO recession in primary position and in contralateral gaze.

METHODS

Records of 43 patients with IO muscle overaction associated with congenital unilateral superior oblique palsy were reviewed retrospectively. Seventeen patients who had a unilateral 10-mm recession (IO attached at 2 mm temporal and 3 mm posterior from the inferior rectus muscle insertion) and 26 patients who had a standard 14-mm recession were evaluated at 3 months postoperatively. The effect of the recession was measured by preoperative hyperdeviation minus postoperative hyperdeviation.

RESULTS

The average preoperative hyperdeviation was 13.4 ± 4.83 prism diopters (PD) in primary position and 16.2 ± 6.32 PD in contralateral gaze in the 10-mm group and 8.0 ± 3.48 PD in primary position and 12.76 ± 4.55 PD in contralateral gaze in the 14-mm group. The average deviation at 3 months postoperatively was 2.1 ± 3.03 in primary position and 2.6 ± 3.95 PD in contralateral gaze in the 10-mm group and 0.8 ± 1.21 in primary position and 1.8 ± 1.95 PD in contralateral gaze in the 14-mm group. The range of self-adjusting effect at 3 months postoperatively was 3 to 20 PD in primary position and 5 to 30 PD in contralateral gaze in the 10-mm group and 3 to 15 PD in primary position and 4 to 24 PD in contralateral gaze in the 14-mm group. The self-grading effect was large and displayed no significant differences at 3 months postoperatively in the 10- and 14-mm groups (P = .104 and .560, respectively).

CONCLUSION

Both IO recession procedures were largely self-grading and no significant differences were evident at 3 months postoperatively.

Refractive errors and strabismus in Down's syndrome in Korea

Purpose

The aims of this study were to examine the distribution of refractive errors and clinical characteristics of strabismus in Korean patients with Down's syndrome.

Methods

A total of 41 Korean patients with Down's syndrome were screened for strabismus and refractive errors in 2009.

Results

A total of 41 patients with an average age of 11.9 years (range, 2 to 36 years) were screened. Eighteen patients (43.9%) had strabismus. Ten (23.4%) of 18 patients exhibited esotropia and the others had intermittent exotropia. The most frequently detected type of esotropia was acquired non-accommodative esotropia, and that of exotropia was the basic type. Fifteen patients (36.6%) had hypermetropia and 20 (48.8%) had myopia. The patients with esotropia had refractive errors of +4.89 diopters (D, ±3.73) and the patients with exotropia had refractive errors of -0.31 D (±1.78). Six of ten patients with esotropia had an accommodation weakness. Twenty one patients (63.4%) had astigmatism. Eleven (28.6%) of 21 patients had anisometropia and six (14.6%) of those had clinically significant anisometropia.

Conclusions

In Korean patients with Down's syndrome, esotropia was more common than exotropia and hypermetropia more common than myopia. Especially, Down's syndrome patients with esotropia generally exhibit clinically significant hyperopic errors (>+3.00 D) and evidence of under-accommodation. Thus, hypermetropia and accommodation weakness could be possible factors in esotropia when it occurs in Down's syndrome patients. Based on the results of this study, eye examinations of Down's syndrome patients should routinely include a measure of accommodation at near distances, and bifocals should be considered for those with evidence of under-accommodation.

Pars plana Ahmed implantation combined with 23-gauge vitrectomy for refractory neovascular glaucoma in diabetic retinopathy

Purpose

To evaluate the efficacy and safety of a pars plana Ahmed valve implantation combined with 23-gauge sutureless vitrectomy in the treatment of patients with medically uncontrolled neovascular glaucoma (NVG) in proliferative diabetic retinopathy (PDR).

Methods

The authors retrospectively reviewed the records of 11 consecutive patients with refractory NVG in PDR who underwent a 23-gauge sutureless vitrectomy combined with pars plana placement of an Ahmed valve implant. Control of intraocular pressure (IOP), pre- and postoperative best-corrected visual acuity and the development of intra- and postoperative complications were evaluated during the follow-up.

Results

The mean follow-up was 12.2 months (range, 8 to 25 months). Mean preoperative IOP was 35.9 ± 6.3 mmHg and mean postoperative IOP at the last visit was 13.3 ± 3.2 mmHg. Control of IOP (8 to 18 mmHg) was achieved in all patients, but 91% (10 of 11 patients) needed antiglaucoma medication (mean number of medications, 1.2 ± 0.6). Postoperative visual acuity improved in 11 eyes, and the logarithmically to the minimum angle of resolution mean visual acuity in these eyes improved from 1.67 ± 0.61 to 0.96 ± 0.67. The complications that occurred were transient hypotony in one case, transitory hypertension in two cases, and postoperative vitreous hemorrhage which spontaneously cleared in two cases.

Conclusions

We suggest the combination of 23-gauge pars plana vitrectomy and Ahmed valve implantation is safe and effective in PDR patients with refractory NVG.

Endogenous aeromonas hydrophila endophthalmitis in an immunocompromised patient

PURPOSE

To report a case of endogenous endophthalmitis due to Aeromonas hydrophila in a patient with distal common bile duct carcinoma and biliary sepsis.

METHODS

A 72-year-old woman with distal common bile duct carcinoma, obstructive jaundice, diabetes mellitus, and hypertension had a 1-day history of blurred vision, redness, and eye discharges in the right eye. An ophthalmic examination showed no light perception vision, increased intraocular pressure, severe corneal edema, severe anterior chamber reaction, exudative membranes on the anterior lens surface, and severe vitreal reaction. There was no ocular history of trauma, infection, or surgery in either eye.

RESULTS

Under the impression of endogenous bacterial endophthalmitis, immediate intraocular cultures and intravitreal antibiotic injections were performed, but the anterior chamber reaction, and the ultrasonogram findings were deteriorated. Evisceration was undertaken because of extrusion of the intraocular contents, and Aeromonas hydrophila was isolated by intraocular culture.

CONCLUSIONS

Endogenous endophthalmitis due to Aeromonas hydrophila is rare, but has a rapid clinical course and a poor prognosis, despite of prompt diagnosis and management.

A silastic sheet found during endoscopic transnasal dacryocystorhinostomy for acute dacryocystitis

Purpose

To report the case of a silastic sheet that was found during an endoscopic transnasal dacryocystorhinostomy for treatment of acute dacryocystitis with necrosis of the lacrimal sac.

Methods

A thirty-two year old male presented with painful swelling on the nasal side of his left lower lid two weeks prior to visiting this clinic. Fourteen years ago, the patient was involved in a traffic accident and underwent surgery to reconstruct the ethmoidal sinus. Lacrimal sac massage showed a regurgitation of a purulent discharge from the left lower punctum. Therefore, the patient was diagnosed with acute dacryocystitis and an endoscopic transnasal dacryocystostomy was performed the next day.

Results

The surgical finding showed severe necrosis around the lacrimal sac and a 20 × 15-mm sized silastic sheet was found crumpled within the purulent discharge. The sheet was removed, the lacrimal sac was irrigated with an antibiotic solution, and a silicone tube was intubated into the lacrimal pathway. After surgery, the painful swelling on the nasal side of left lower lid resolved gradually, and there were no symptomatic complications three months later.

Conclusions

We report the first case where a silastic sheet applied during a facial reconstruction had migrated adjacent to the lacrimal sac resulting in severe inflammation.

Clinical effect of early surgery in infantile exotropia

To evaluate the effects of early surgical intervention in infantile exotropia on the motor and sensory functions, we reviewed the records of 17 subjects diagnosed with exotropia before the age of 12 months, receiving surgery before the age of 24 months, with a follow-up period greater than one year, between 1996 and 2000. Of the 17 subjects (6 intermittent, 11 constant), 14 (82%) (6 intermittent, 8 constant) had a final horizontal deviation of <10 PD, with 3 (18%) needing a re-operation. Fusion and gross binocularity were developed in 7 (4 intermittent, 3 constant), and 11 (6 intermittent, 5 constant) subjects, respectively. Seven subjects developed stereopsis of 200 seconds or better, and 5 of the 6 with intermittent exotropia (83%) being involved. In conclusion, over 80% of the successful alignments were obtained with surgery before the age of 24 months in infantile exotropia, which was similar to previous studies. Furthermore, early surgical intervention, particularly in the intermittent phase, resulted in more effective sensory function.

Measurement of acute pain after eye surgery in children

This study was performed to assess the degree of acute pain in children following eye surgery using a Face Pain Rating Scale (FPRS), with a validity and reliability test employing a Numeric/Word Graphic Rating Scale (NWGRS). The degree of pain was obtained at 2, 4, 6, 8 and 24 hours after surgery using the FPRS and NWGRS. The changes in pain intensities were analyzed using a RM-ANOVA, while the relationship between the FPRS and NWGRS was analyzed by a Pearson coefficient in SPSS/WIN. Two third of the children experienced pain equal to, or greater, than moderate to severe, and about one fifth of the subjects expressed the most severe pain at 2 hours after surgery. At 4 hours after surgery, 95.3% of the children still complained of pain, and 8 hours after surgery, 82.8% of the patients experienced 'a little bit' or 'a little more' pain or discomforts. At 1 day after surgery, only 34.4% of children were free of pain. A high correlation between the FPRS and NWGRS was identified over 5 time-points (.887 < r < .735). The gender, type of the surgery and past operation experience had no effects on the degree of pain. Our results suggest that FPRS is a reliable and valid measurement for acute pain assessment in Korean children following eye surgery, and warrants application in the integrated clinical protocol, including non-pharmacological and pharmacological management of acute pediatric pain reduction following surgery.