Metabolic Deregulation of the Blood-Outer Retinal Barrier in Retinitis Pigmentosa

Retinitis pigmentosa (RP) initiates with diminished rod photoreceptor function, causing peripheral and nighttime vision loss. However, subsequent loss of cone function and high-resolution daylight and color vision is most debilitating. Visual pigment-rich photoreceptor outer segments (OS) undergo phagocytosis by the retinal pigment epithelium (RPE), and the RPE also acts as a blood-outer retinal barrier transporting nutrients, including glucose, to photoreceptors. We provide evidence that contact between externalized phosphatidylserine (PS) on OS tips and apical RPE receptors activates Akt, linking phagocytosis with glucose transport to photoreceptors for new OS synthesis. As abundant mutant rod OS tips shorten in RP, Akt activation is lost, and onset of glucose metabolism in the RPE and diminished glucose transport combine to cause photoreceptor starvation and accompanying retinal metabolome changes. Subretinal injection of OS tip mimetics displaying PS restores Akt activation, glucose transport, and cone function in end-stage RP after rods are lost.

Wang et al. show that onset of glucose metabolism in the retinal pigment epithelium (RPE), which acts as the blood-outer retinal barrier, and inhibition of RPE glucose transport to photoreceptors combine to cause photoreceptor starvation and vision loss in retinitis pigmentosa.

Efficacy of fixed-dosing aflibercept for treating polypoidal choroidal vasculopathy: 1-year results of the VAULT study

Purpose

To investigate fixed-dosing aflibercept for treating polypoidal choroidal vasculopathy (PCV).

Methods

This phase IV, prospective, single-arm, interventional case series was conducted in eight centers. Forty treatment-naïve PCV patients were administered three monthly doses of intravitreal aflibercept (2.0 mg) and an injection every 2 months thereafter. Best-corrected visual acuity (BCVA) and central subfield macular thickness (CSMT) were measured at each visit. Fluorescein and indocyanine green angiography (ICGA) were performed at baseline, 3 and 12 months. The primary outcome measure was the proportion of patients who maintained BCVA (<15 letters loss) at 12 months. Changes in BCVA, macular appearance, and polypoidal lesion appearance were also examined.

Results

Thirty-five eyes (87.5 %) had maintained BCVA at 12 months. Average BCVA was significantly higher at 12 months (20/53, 64.2 letters) than at baseline (20/80, 55.1 letters, 9-letter gain; P < .001). Mean CSMT was significantly lower at 12 months (253.6 μm) than at baseline (365.2 μm, P < .001). The macula was dry in 32 (76.2 %), 27 (64.3 %), and 24 eyes (60.0 %) at 3, 6, and 12 months respectively. Fourteen eyes (33.3 %) had a fluid recurrence or increase at 6 months, and they had a significantly lower vision gain (P = .005) than other patients at 12 months. Complete polyp regression occurred in 26 eyes (66.7 %) at 12 months.

Conclusions

Fixed-dosing aflibercept showed favorable outcomes in PCV patients at 12 months. However, some patients had worse outcomes because of fluid recurrence during maintenance dosing, and these patients would require additional treatments.

Clinical features of infectious endophthalmitis in South Korea: a five-year multicenter study

BACKGROUND

To investigate clinical features of infectious endophthalmitis over five years in a South Korean population.

METHODS

Medical records of consecutive patients diagnosed with infectious endophthalmitis at eight institutions located in Gyeongsangnam-do and Pusan city between January 1, 2004 and July 31, 2010 were reviewed.

RESULTS

A total of 197 patients were diagnosed and treated. An average of 30.0 infectious endophthalmitis per year was developed. The annual incidence rate of postoperative endophthalmitis during 2006~2009 was 0.037%. The ratios of male to female and right to left were 50.2%: 49.8 % and 54.8%: 43.2%, respectively. Eighth decade and spring were the peak age (36.6%) and season (32.0%) to develop the infectious endophthalmitis. The most common past history in systemic disease was hypertension (40.4%), followed by diabetes (23.4%). Cataract operation (60.4%) was the most common cause, among which most of them was uneventful phacoemulsification (95.9%). Corneal laceration (51.6%) and liver abscess (42.9%) were the most common causes of traumatic and endogenous endophthalmitis, respectively. The percentages of patients with initial and final visual acuity less than counting fingers were 62.6% and 35.2%, respectively. Treatment with vitrectomy with or without intravitreal antibiotics injection was administered to 72.6% of patients, while 17.3% received intravitreal antibiotics only.

CONCLUSIONS

Our study revealed that the development of infectious endophthalmitis was related with seasonal variation and increased during our study period. Pars plana vitrectomy was preferred for the treatment of infectious endophthalmitis in South Korea.

TOPOGRAPHIC CHANGES OF THE MACULA AFTER CLOSURE OF IDIOPATHIC MACULAR HOLE

PURPOSE

To investigate retinal displacement in the macula after surgical closure of idiopathic macular hole and to identify factors correlated with displacement.

METHODS

This retrospective multicenter study included 73 eyes of 73 patients having idiopathic macular hole. A custom program was developed to compare the position of the retinal vessels in the macula between preoperative and postoperative photographs. En face images of a 6 mm × 6 mm optical coherence tomography volume scans were registered to calculate the scale. A grid comprising 16 sectors in 2 rings (inner; 2-4 mm and outer; 4-6 mm) was superimposed. The displacement of the retinal vessels was measured as a vector value by comparing the location of the retinal vessels in each sector. The correlation between displacement and various clinical parameters was analyzed.

RESULTS

The average displacement was 57.2 μm at an angle of -3.3° (nasal and slightly inferior). Displacement was larger in the inner ring (79.2 μm) than in the outer ring (35.3 μm, P < 0.001), and larger in the temporal sectors than in the corresponding nasal sectors (P ≤ 0.008). Inferior and superior displacement was noted in the superior and inferior sectors, respectively. Multiple regression analysis revealed that basal horizontal macular hole diameter and size of internal limiting membrane removal were independent factors of displacement.

CONCLUSION

The macula was displaced centripetally, nasally, and slightly inferiorly after surgical closure of idiopathic macular hole. Hole closure, contraction of the nerve fiber layer, and gravity are the suggested mechanisms of macular displacement caused by internal limiting membrane peeling.

One-Year Results of Treatment of Diabetic Macular Edema with Aflibercept Using the Treat-and-Extend Dosing Regimen: the VIBIM Study

INTRODUCTION

The purpose of this study was to report the one-year results of treatment of diabetic macular edema (DME) with aflibercept using a treat-and-extend regimen (TER).

METHODS

This was a prospective, multicenter, single-arm study planned for 2 years. The eyes received 5 consecutive intravitreal injections of 2 mg of aflibercept every 4 weeks, and the interval between injections was then adjusted by 2 weeks based on changes in the central subfield macular thickness (CSMT). If the CSMT was worse, stable, or better, the interval was shortened, extended, or maintained, respectively. The primary outcome measure was the change in best-corrected visual acuity (BCVA) from baseline to 104 weeks, and the secondary outcome was the change in BCVA from baseline to 52 weeks.

RESULTS

Of the 48 patients enrolled, 46 completed a 1-year visit. BCVA improved significantly by 9.1 letters (95% confidence interval: 5.3-13.0 letters) from 56.2 letters at baseline (p < 0.001), and CSMT decreased by -171.7 μm from 489.4 to 317.7 μm (p < 0.001). The proportion of eyes having 20/40 or better vision increased from 17.4 to 41.3%, and the proportion of eyes that gained ≥15 letters was 28.3%. The mean number of injections was 8.5 times for 52 weeks. Worsening of macular edema did not occur in 76.1% of eyes during the extension period, and the interval between injections was extended to 12 weeks in 73.9% of eyes at 52 weeks.

CONCLUSIONS

The TER showed 1-year efficacy comparable to that of the fixed dosing regimen of pivotal trials, and its flexible dosing would prevent overtreatment.

Topical cell-free conditioned media harvested from adipose tissue-derived stem cells promote recovery from corneal epithelial defects caused by chemical burns

Corneal chemical burns can lead to blindness following serious complications. As most of these complications are caused by failure of reepithelization during the acute phase, treatment at this stage is critical. Although there have been some studies on corneal injury recovery using adipose tissue-derived stem cells (ADSCs), none has reported the effect of topical cell-free conditioned culture media (CM) derived from ADSCs on corneal epithelial regeneration. Here, the best conditions for CM were selected and used for in vitro and in vivo experiments. Corneal burn in rats was induced using 100% alcohol. The chosen CM was administered to corneal burn rats (CM-treated [CT] group) four times a day for three days and this group was compared with the normal control and corneal burn (CB) groups. Biomicroscopic fluorescence images and the actual physical corneas were taken over time and used for analysis. mRNA levels of hepatocyte growth factor and epidermal growth factor (EGF) were significantly increased, whereas those of vascular endothelial growth factor, interleukin (IL)-1β, IL-6, IL-10, and matrix metalloproteinase-9 were significantly decreased in the CT group compared with those in the CB group. The numbers of proliferating cell nuclear antigen- and zonular occludens-1-positive cells in the CT group were significantly higher than those in the CB group. The macrophage-infiltrating corneas in the CT group expressed significantly more of the M2 marker arginase than corneas in the CB group. Optimal CM (× 0.5 concentration) treatment significantly accelerated the migration of corneal epithelial cells and induced upregulation of the expression of IL-6, EGF, and C-X-C chemokine receptor type 4 mRNAs. Overall, in this study, topical administration of cell-free CM promoted regeneration of the corneal epithelium after induction of chemical burns.

Two-year outcomes of the treat-and-extend regimen using aflibercept for treating diabetic macular oedema

This study was performed to investigate the efficacy of the treat-and-extend regimen using aflibercept for treating diabetic macular oedema (DME). This prospective, multicentre, interventional, single-arm, 104-week clinical trial included 48 patients with DME visual impairment. The patients’ eyes received five consecutive intravitreal injections (2 mg aflibercept) every four weeks with two-week adjustments based on central subfield macular thickness (CSMT) changes. Injections were deferred when CSMT was stable. The number of injections, best-corrected visual acuity (BCVA), CSMT, and diabetic retinopathy severity scale scores were analysed. Compared to baseline, BCVA improved by + 9.1 letters at 52 weeks and was maintained with + 9.4-letter gain at 104 weeks (P < 0.001). Between baseline and 104 weeks, CSMT decreased from 489 to 298 μm (P < 0.001) and eyes with vision ≥ 20/40 increased from 17.4 to 43.5% (P = 0.007). The mean number of injections decreased from 8.5 in year one to 3.9 in year two. The injection interval was extended to ≥ 12 weeks in 56.5% of patients. The treat-and-extend regimen of aflibercept in DME showed 2-year efficacy comparable to that of fixed dosing regimens. The flexible dosing of this regimen reduced the number of injections in year two while maintaining efficacy.

An automatic screening method for strabismus detection based on image processing

Purpose

This study aims to provide an automatic strabismus screening method for people who live in remote areas with poor medical accessibility.

Materials and methods

The proposed method first utilizes a pretrained convolutional neural network-based face-detection model and a detector for 68 facial landmarks to extract the eye region for a frontal facial image. Second, Otsu’s binarization and the HSV color model are applied to the image to eliminate the influence of eyelashes and canthi. Then, the method samples all of the pixel points on the limbus and applies the least square method to obtain the coordinate of the pupil center. Lastly, we calculated the distances from the pupil center to the medial and lateral canthus to measure the deviation of the positional similarity of two eyes for strabismus screening.

Result

We used a total of 60 frontal facial images (30 strabismus images, 30 normal images) to validate the proposed method. The average value of the iris positional similarity of normal images was smaller than one of the strabismus images via the method (p-value<0.001). The sample mean and sample standard deviation of the positional similarity of the normal and strabismus images were 1.073 ± 0.014 and 0.039, as well as 1.924 ± 0.169 and 0.472, respectively.

Conclusion

The experimental results of 60 images show that the proposed method is a promising automatic strabismus screening method for people living in remote areas with poor medical accessibility.

Intraperitoneal administration of adipose tissue-derived stem cells for the rescue of retinal degeneration in a mouse model via indigenous CNTF up-regulation by IL-6

As the world's population begins to age, retinal degeneration is an increasing problem, and various treatment modalities are being developed. However, there have been no therapies for degenerative retinal conditions that are not characterized by neovascularization. We investigated whether transplantation of mouse adipose tissue-derived stem cells (mADSC) into the intraperitoneal space has a rescue effect on NaIO3 -induced retinal degeneration in mice. In this study, mADSC transplantation recovered visual function and preserved the retinal outer layer structure compared to the control group without any integration of mADSC into the retina. Moreover, endogenous ciliary neurotrophic factor (CNTF) was elevated in the retinas of mADSC-treated mice. We found that lipopolysaccharide (LPS) or LPS-stimulated monocyte supernatant induced the secretion of granulocyte colony stimulating factor (GCSF), CD54, CXCL10, interleukin-6 (IL-6), and CCL5 from the mADSC by cytokine array. Network inference was conducted to investigate signaling networks related to CNTF regulation. Based on bioinformatics data, the expression of IL-6 was related to the expression of CNTF. Additionally, intravitreal injection of IL-6 in rats produced up-regulation of endogenous CNTF in the retina. mADSC had a rescue effect on retinal degeneration through the up-regulation of endogenous CNTF by IL-6. Thus, transplantation of mADSC could be a potential treatment option for retinal degeneration.

Comparison of the most common isolates of postoperative endophthalmitis in South Korea; Enterococcus species vs coagulase-negative staphylococci

BACKGROUND

To compare the related factors or manifestations of the two most common isolates of post-operative endophthalmitis, which were Enterococcus spp. and coagulase-negative staphylococci (CNS) in South Korea.

METHODS

Medical records were reviewed for cases of post-operative endophthalmitis caused by Enterococcus spp. and CNS at eight institutions between January 2004 and July 2010. Various factors including age, sex, residence, systemic diseases, smoking and drinking history, and best corrected visual acuity, and length of time between causative intraocular surgery and symptom development were compared between the two groups.

RESULTS

The total number of post-operative endophthalmitis cases was 128 and in 116 cases, microbiological culture tests from the aqueous humor or vitreous were performed. Among these cases, 67 (57.8%) were culture proven. Among these 67 cases, 19 (28.4%) were caused by Enterococcus spp., 14 (20.9%) were caused by Staphylococcus epidermidis endophthalmitis, and 5 (7.5%) were caused by other CNS spp. Age, sex, causative procedure, past medical history, social history, and laterality were not different in the two groups. Mean initial and final visual acuity were significantly worse in the Enterococcus spp. endophthalmitis group than in the CNS group (p = 0.049, 0.042, respectively). Length of time between the causative procedure and symptom development was significantly shorter in cases of Enterococcus spp. endophthalmitis (p = 0.004).

CONCLUSIONS

Enterococcus spp. induce more severe and rapid-onset postoperative endophthalmitis than CNS. Infectious endophthalmitis developed within 2 days after cataract operation could be caused by Enterococcus spp. and have chance to be poor prognosis in South Korea.

Title: efficacy of intravitreal dexamethasone implant on hard exudate in diabetic macular edema

Background

To investigate the effect of intravitreal dexamethasone implant (DEX implant) on hard exudate (HE) accompanying diabetic macular edema (DME).

Methods

This study was a non-comparative non-randomized 1-year prospective interventional study. Patients with DME and HE were treated using DEX implant two or three times. Color fundus photography and optical coherence tomography (OCT) were performed at every visit. HE area was measured semi-automatically from the fundus photographs.

Results

Thirty-five patients completed the study. Eleven patients (31.4%) received two injections, while the remaining received three times. HE area (primary outcome) significantly decreased from 1.404±2.094 mm2 (baseline) to 0.212±0.592 mm2 (last visit), which was 24% of the baseline HE area (P<0.001). HE1500 (HE within 1500 μm from the fovea) area also decreased significantly from 0.382±0.467 mm2 to 0.066±0.126 mm2 (P<0.001). Furthermore, anaverage best corrected visual acuity (BCVA) improvement of 4.4 Early Treatment Diabetic Retinopathy Study (ETDRS) letters was observed (from 49.9±18.3 to 54.3±20.4 letters) (P= 0.008). Central macular thickness (CMT) decreased from 455.8±23.6 μm to 366.8±31.1 μm (P=0.009). Repetitive measurements for entire study duration was analyzed using generalized estimating equations (GEE), where BCVA was related to age, CMT, and HE1500 area in multivariate analyses.

Conclusion

DEX implant could reduce and suppress HE in DME for one year with two or three injections. And centrally located HE area (HE1500 area) is related to vision.

Trial registration

ClinicalTrials.gov, NCT02399657, Registered 26 March 2015. 

Time Series Changes in Cataract Surgery in Korea

PURPOSE

We analyzed time series changes in cataract surgeries in Korea, and provide basic data to enhance the efficiency of medical services for cataract surgery.

METHODS

Among cataract surgery statistics registered in the Korean National Health Insurance Cooperation from 2006 to 2012, we used data regarding the number of patients and operations and the number of patients and operations per 100,000 people. We analyzed various time series changes, including differences by sex and age.

RESULTS

The total numbers of patients from 2006 to 2012 by year were 207,370; 228,170; 250,289; 268,548; 289,867; 308,111; and 302,182, respectively. The total numbers of operations from 2006 to 2012 by year were 272,920; 305,807; 338,332; 365,874; 398,338; 428,158; and 420,905, respectively. The number of patients and operations per 100,000 people were highest in men 80 to 84 years old and women 75 to 79 years old. Comparing the number of operations in 2006 and after, the patient age group with the highest increase rate changed from over 85 years old to 75-79 years old since 2010 in men and from over 85 years old to 50-54 years old since 2009 in women. For each year investigated, the number of operations performed was higher than the number of patients who received operations.

CONCLUSIONS

Over the study period, the number of cataract surgeries increased, while the age of cataract patients decreased. Additionally, the number of cataract-related surgeries increased in relation to the number of patients.

Effect of prophylactic anti-VEGF injections on the prevention of recurrent vitreous hemorrhage in PDR patients after PRP

We evaluated the effectiveness of intravitreal anti-vascular endothelial growth factor (anti-VEGF) antibody injection (IVAI) for the prevention of recurrent vitreous hemorrhage (VH) due to neovascularization on disc (NVD) in patients with proliferative diabetic retinopathy (PDR) after panretinal photocoagulation (PRP). This retrospective case series reviewed the medical records of 12 PDR patients with recurrent VH after PRP from NVD. The interval between IVAIs was decided on the basis of the interval between VH recurrences after the initial IVAI, and NVD regression/recurrence during follow-up. We recorded the success rate of VH prevention, and the interval between IVAIs. Fundus examination revealed NVD regression at 1 month after the injection. However, NVD progressed gradually and VH recurred after 3–4 months. Thereafter, IVAIs were administered every 3–4 months; VH did not recur and visual acuity remained stable during the treatment period. In one case, NVD did not recur after 4 years of periodic injections. No systemic or ocular complications of IVAI were observed. In conclusion, proactive and periodic IVAIs (at 3–4-month intervals) may prevent recurrent VH in association with NVD in PDR patients after PRP.

Conditioned secretome of adipose-derived stem cells improves dextran sulfate sodium-induced colitis in mice

BACKGROUND

Inflammatory bowel diseases (IBD) is related to uncontrolled immune response. Currently, there is no successful treatment for significant improvement in IBD. Stem cells display their therapeutic effects through their repopulating capacity or secreting factors.

AIM

To investigate the effects of conditioned mouse adipose-derived stem cells (mADSCs) secretome on colitis-induced mice.

METHODS

mADSCs were isolated from adipose tissue of C57BL/6 mice. Conditioned mADSCs secrectome was obtained by culturing of mADSCs with lipopolysaccharides (LPS, 1 μg/mL) for 24 h. Acute colitis was induced by 2% dextran sulfate sodium (DSS) drinking water for 7 d and then normal drinking water for 4 d. The mice were treated with normal culture medium (NM group), conditioned mADSCs secretome (CM group) or mADSCs (SC group). The length of colon and histopatholgy of colon tissues were evaluated. The mRNA expression levels of inflammatory cytokines in colon tissue and the serum interleukin (IL)-6 levels were determined.

RESULTS

The isolated mADSCs maintained the mADSCs specific gene expression profiles during experiment. The conditioned mADSCs secretome released by the treatment of mADSCs with LPS contained mainly inflammatory chemokines, colony-stimulating factors and inflammatory cytokines. The loss of body weight and reduction in colon length were ameliorated in the CM group. The conditioned mADSCs secretome reduced the histological score in colon tissue. The expression of IL-1b and IL-6 mRNAs in colon tissues significantly inhibited in the CM group compared to SC group and NM group, respectively. The elevation of serum IL-6 levels was also ameliorated in the CM group. These results indicate that the conditioned mADSCs secretome suppressed the synthesis of inflammatory cytokines in damaged colon tissue and the elevation of serum IL-6 concentration in DSS-induced mice.

CONCLUSION

Conditioned mADSCs secretome might play regenerative roles by the suppression of IL-6 in serum and tissue during acute colitis, and may be more effective than stem cells themselves in the regeneration of colon tissue.

An improved strabismus screening method with combination of meta-learning and image processing under data scarcity

Purpose

Considering the scarcity of normal and strabismic images, this study proposed a method that combines a meta-learning approach with image processing methods to improve the classification accuracy when meta-learning alone is used for screening strabismus.

Methods

The meta-learning approach was first pre-trained on a public dataset to obtain a well-generalized embedding network to extract distinctive features of images. On the other hand, the image processing methods were used to extract the position features of eye regions (e.g., iris position, corneal light reflex) as supplementary features to the distinctive features. Afterward, principal component analysis was applied to reduce the dimensionality of distinctive features for integration with low-dimensional supplementary features. The integrated features were then used to train a support vector machine classifier for performing strabismus screening. Sixty images (30 normal and 30 strabismus) were used to verify the effectiveness of the proposed method, and its classification performance was assessed by computing the accuracy, specificity, and sensitivity through 5,000 experiments.

Results

The proposed method achieved a classification accuracy of 0.805 with a sensitivity (correct classification of strabismus) of 0.768 and a specificity (correct classification of normal) of 0.842, whereas the classification accuracy of using meta-learning alone was 0.709 with a sensitivity of 0.740 and a specificity of 0.678.

Conclusion

The proposed strabismus screening method achieved promising classification accuracy and gained significant accuracy improvement over using meta-learning alone under data scarcity.

Emerging Enterococcus isolates in postoperative endophthalmitis by selection pressure of fluoroquinolones: an 11-year multicenter and experimental study

Postoperative endophthalmitis (PE) is the devastating complication that frequently results in vision loss. Recently, enterococcus have emerged as a major cause of PE in several countries and resulted in poor visual outcome. However, the reason remains elusive. We investigate whether selection pressure of fluoroquinolone exerts effects on microorganism profiles isolated from PE. Medical records of patients who were diagnosed with PE at eight resident training institutions between January 2004 and December 2015 were reviewed. The most common isolate was Enterococcus faecalis (28.0%), followed by Staphylococcus epidermidis (18.6%) and other coagulase negative Staphylococci (7.6%). However, the rates of E. faecalis isolated from conjunctival microbes were 6.2% (16/257) and their resistance to fluoroquinolones was higher than those of S. epidermidis. In vitro and in vivo co-culture models of E. faecalis and S. epidermidis were established for survival assays after administration of fourth-generation fluoroquinolone. In in vitro co-culture model, the survival assay of E. faecalis and S. epidermidis against the treatment of moxifloxacin showed that E. faecalis survived significantly better than S. epidermidis in the presence of moxifloxacin 1 µg/mL and more. In in vivo co-culture model, E. faecalis survived significantly better than S. epidermidis after topical treatment of moxifloxacin (5 mg/mL). E. faecalis has been the most common causative strain of PE in Korea. We suggest that the increase of E. faecalis in PE could be associated with the selection pressure of fourth-generation fluoroquinolone.

Summary:Enterococcus spp. have emerged as a leading causative strain of postoperative endophthalmitis in 11-year clinical data. We suggest that the increase of Enterococcus spp. is associated with the selection pressure of fourth-generation fluoroquinolone.

Changes in Opacification of Hydrophobic Acrylic Intraocular Lenses According to Temperature and Hydration

Purpose

To investigate optic opacification of hydrophobic acrylic intraocular lens (IOL) depending on hydration and temperature conditions.

Methods

IOL (Acrysof^® MA60BM Alcon, Fort Worth, Texas, USA) extracted from a 55-year-old male who underwent binocular cataract 11 years ago were used for the analysis. On slit lamp examination, the binocular IOL optics showed homogenous opacification. After extraction of the IOLs, the IOL opacification disappeared during dry storage at 4°C. To investigate the changes in IOL opacification according to temperature and hydration, an extracted IOL was stored in either dry conditions or normal saline at 4°C, room temperature, or 37°C for 24 hours, and then the degree of haziness was examined. To investigate the impact of an opaque optic on visual function, light transmission was performed using an ultraviolet-visible spectrophotometer (U-3000, Hitachi High-Technologies Corp., Tokyo, Japan).

Results

The extracted IOL optics at 4°C, room temperature, and 37°C were transparent at dry conditions. When the dried IOL was immersed in normal saline at room temperature and 37°C, opacification appeared. However, when the dried IOL was immersed in normal saline at 4°C, opacification of the IOL did not appear. When compared with the control, light transmission of the extracted IOLs from the right and left eyes stored in 37°C normal saline decreased by 4.7% at 453 nm and by 5.1% at 482 nm, respectively.

Conclusion

In acrylic hydrophobic IOLs, optic opacification can occur depending on temperature and hydration conditions.

Increased myofiber size and reduced satellite cell numbers in medial rectus muscle of patients with intermittent exotropia

PURPOSE

To elucidate the differences in muscle bundle and satellite cells in medial rectus muscle through histological and Immunofluorescence studies of intermittent exotropia patients and normal controls. Materials and Methods: From January 2015 to December 2017, 15 patients who underwent medial rectus resection surgery at Kosin University Gospel Hospital were enrolled. Four medial recti muscles collected from two brain-dead men without strabismus were used as controls and compared with the intermittent exotropia group. Hematoxylin and eosin (HE) staining were performed, and all muscle bundle diameters were measured with the Image J program and compared to the mean value. Immunological staining for MyoHC (Myosin Heavy Chain), PAX7 (Transcription Factor), and PCNA (Proliferating Cell Nuclear Antigen) were performed to analyze the distribution of myocytes and PAX7-positive and PCNA-positive cells. Results: The mean ages of the strabismus and control groups were 17.33 ± 13.05 and 22.0 ± 5.85 years, respectively, and the male to female ratio was 7:2 and 2:0. The average angle of deviation in the exotropia patients was 36.0 ± 16.83 prism diopters. The mean muscle bundle diameter under light microscopy was 60.21 ± 1.48 in the exotropia group and 52.27 ± 0.74 in the control group. The exotropia group showed significantly greater mean muscle bundle diameter (p < .001) and diameter regularity than the control group. The PAX7(+)/muscle bundle number ratio was 0.016 ± 0.014 and 0.056 ± 0.015 in the exotropia group and control group, respectively (p < .001), and the PCNA(+)/muscular bundle number ratio was 0.015 ± 0.017 and 0.182 ± 0.102 (p < .001). Both were significantly higher in the control group compared to that in the exotropia patients. Conclusion: In the exotropia group, mean diameter of medial rectus muscle bundle was significantly larger than that of control group. The ratios of PAX7 and PCNA to muscle bundle number were significantly higher in the control group than intermittent extropia group. We found the negative relationship between activation of satellite cells and muscle bundle diameter, and it might take one step forward to elucidate the pathogenesis of intermittent extropia.

Fluoroquinolone resistance of Staphylococcus epidermidis isolated from healthy conjunctiva and analysis of their mutations in quinolone-resistance determining region

BACKGROUND

Staphylococcus epidermidis is the most common pathogen in postoperative endophthalmitis and causes various infectious eye diseases. However, there is very little information on fluoroquinolone antibiotic resistance to S. epidermidis identified in conjunctival microbe and analysis of related genes. Here, the authors investigated the rate of resistance to fluoroquinolones of Staphylococcus epidermidis isolated from normal conjunctival microbes and mutations in the quinolone-resistance determining region (QRDR).

METHODS

377 eye samples from 187 patients who underwent intravitreal injection and cataract surgery were included. Specimens were taken from the bilateral lower conjunctival sacs using a cotton swab and cultured. The cultures were identified using MALDI-TOP MS and gyrA, gyrB, parC, and parE gene mutations of QRDR were confirmed by DNA extraction from resistant strains of S. epidermidis with a micro-dilution method using ciprofloxacin, levofloxacin, and moxifloxacin.

RESULTS

The culture positive rate was 61.8% (231) for 374 eye samples. Of the 303 total strains cultured, S. epidermidis was the most common with 33.7% (102). Ten types of gene mutations were observed in the resistant S. epidermidis of 21 strains. One-point mutation was observed mainly in gyrA and parC, and a small number of mutations were observed in parE in the form of a double point mutations. When there were multiple point mutations in both gyrA and parC, the highest minimum inhibitory concentration was observed.

CONCLUSIONS

The quinolone resistance rate of S. epidermidis increased in comparison with previous studies, and resistant S. epidermidis showed mostly QRDR mutations, which were mainly found in gyrA and parC, and showed strong resistance when mutated in both genes.

Surgically induced changes in retinal vessel diameter, retinal nerve fibre layer thickness, and the optic disc after 23-gauge pars plana vitrectomy

The aim of the study is to investigate the retinal vascular calibre, retinal nerve fibre layer's thickness, and optic disc changes in patients after pars plana vitrectomy. We examined 40 eyes in 40 patients who had undergone unilateral pars plana vitrectomy at three time points: prior to surgery, and at 3 and 6 months after the operation. The diameters of central retinal arteries and veins were measured using retinal photographs. The central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were calculated using the revised Parr-Hubbard formula. Retinal nerve fibre layer thickness was obtained using Stratus optical coherence tomography. The cup-to-disc vertical ratio of the optic disc was evaluated using stereo optic disc photography. There were no significant differences between the eyes of individual patients before the operation. Cup-to-disc vertical ratios of the optic disc were significantly increased 3 and 6 months postoperatively (p < 0.01, p < 0.01), and there was a significant difference between the operative eye and fellow eye at the same time points (p < 0.01, p < 0.01). Changes in CRAE and CRVE in the operative eyes were significantly larger than the fellow eyes 6 months postoperatively (p < 0.01, p < 0.01). The retinal nerve fibre layer thickness showed no significant changes. While there were no changes in retinal nerve fibre layer thickness, vitrectomy induced changes in the cup-to-disc vertical ratio of the optic disc and retinal vessel diameter for at least 6 months after surgery.

Delayed-onset endophthalmitis associated with Achromobacter species developed in acute form several months after cataract surgery: Three case reports

BACKGROUND

Achromobacter species-associated endophthalmitis is rare and may present as either acute or chronic postoperative endophthalmitis. Delayed-onset Achromobacter species endophthalmitis appearing in acute presentation that develops more than several months after cataract surgery is very rare. Intraocular lens (IOL) removal is commonly recommended to treat Achromobacter species endophthalmitis, which is based on previous studies. Here, we report the results of surgery without IOL removal when treating patients with delayed-onset postoperative Achromobacter species endophthalmitis that developed in an acute form.

CASE SUMMARY

Three patients visited our ophthalmology clinic due to visual impairment that began 2-3 d earlier. They had undergone cataract surgery 5-18 mo prior. Best-corrected visual acuity of the diseased eye was between counting fingers at 30 cm to non-light perception. They showed conjunctival injection, inflammation in the anterior chamber (cell reaction 4+) and hypopyon formation. The patients were diagnosed with infectious endophthalmitis and immediately underwent pars plana vitrectomy, anterior chamber irrigation and intravitreal injection of ceftazidime and vancomycin. Before fluid infusion, a vitreous specimen was obtained. In all cases, the IOLs were not removed. Achromobacter species was detected on vitreous specimen culture. After surgery, the vitreous opacity decreased gradually and there was little retinal damage. At 1 mo after treatment, the best-corrected visual acuity had improved to 20/50 and 20/40.

CONCLUSION

Delayed onset postoperative endophthalmitis caused by Achromobacter species can appear in an acute form. All patients responded well to early vitrectomy and administration of empirical antibiotics including ceftazidime. There was no need for IOL removal during surgery.

Rod photoreceptor clearance due to misfolded rhodopsin is linked to a DAMP-immune checkpoint switch

Chronic endoplasmic reticulum stress resulting from misfolding of the visual pigment rhodopsin (RHO) can lead to loss of rod photoreceptors, which initiates retinitis pigmentosa, characterized initially by diminished nighttime and peripheral vision. Cone photoreceptors depend on rods for glucose transport, which the neurons use for assembly of visual pigment-rich structures; as such, loss of rods also leads to a secondary loss of cone function, diminishing high-resolution color vision utilized for tasks including reading, driving, and facial recognition. If dysfunctional rods could be maintained to continue to serve this secondary cone preservation function, it might benefit patients with retinitis pigmentosa, but the mechanisms by which rods are removed are not fully established. Using pigs expressing mutant RHO, we find that induction of a danger-associated molecular pattern (DAMP) "eat me" signal on the surface of mutant rods is correlated with targeting the live cells for (PrCR) by retinal myeloid cells. Glucocorticoid therapy leads to replacement of this DAMP with a "don't eat me" immune checkpoint on the rod surface and inhibition of PrCR. Surviving rods then continue to promote glucose transport to cones, maintaining their viability.