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

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

Comparison of Vision-related Quality of Life Between Normal Tension Glaucoma and Primary Open-angle Glaucoma.

PRCIS: Although there was little difference in overall vision-related quality of life (VRQOL) between patients with normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG) after controlling for confounding factors, POAG tended to have poorer VRQOL, especially in social functioning and dependency, than NTG. PURPOSE: The fundamental goal of treatment of patients with glaucoma is to preserve their VRQOL. The aim of this study was to compare VRQOL between patients with NTG and those with POAG. MATERIALS AND METHODS: The self-reported National Eye Institute Visual Function Questionnaire (NEI VFQ-25) survey was performed, including clinical, demographic, and socioeconomic data from 506 Korean patients with NTG and 287 with POAG. The mean deviation of the integrated binocular visual field was calculated using the best location method. The NEI VFQ-25 results were evaluated by Rasch analysis to control item difficulty and variation in individual response ability. Propensity score matching was used to control for various confounding factors affecting VRQOL. RESULTS: Although patients with POAG tended to have worse VRQOL than those with NTG, there was no statistically significant between-group difference in ocular pain, near and distance activities, mental health, role difficulties, ability to drive, and the overall composite score. However, the social functioning (P=0.016) and dependency (P=0.026) were significantly poorer in POAG patients. CONCLUSIONS: Overall VRQOL in patients with NTG and POAG was found to be similar. However, social functioning and dependency were significantly worse in those with POAG. These findings are relevant to supporting glaucoma patients.

Clinical Manifestation and Risk Factors Associated With Remission in Patients With Filamentary Keratitis.

PURPOSE: This study investigated the clinical manifestation and risk factors associated with remission in filamentary keratitis. DESIGN: Retrospective, interventional, comparative case series. METHODS: We retrospectively reviewed the medical records of 116 patients with filamentary keratitis diagnosed and treated between January 2012 and December 2018. We investigated the 5 causative factors including brain lesion, dry eye syndrome, autoimmune disease, ocular surgery or injury, and other conditions; treatment methods and duration; and remission status, and analyzed the risk factors associated with remission. RESULTS: The mean age of the patients was 56.9 ± 19.1 years and the mean follow-up duration was 14.9 ± 22.8 months. The most common underlying condition associated with filamentary keratitis was identified as a brain lesion (36.2%), followed by dry eye syndrome (30.2%) and autoimmune disease (24.1%). A comparison of remission rates among the causative factors revealed that cases associated with brain lesions had significantly lower remission rates (33.3%) than those associated with other causative factors (>60%) (P = .001). After adjustment for sex, age, diabetes mellitus, and hypertension, the treatment failure rate in patients affected by brain lesions was 6.602-fold higher than that associated without brain lesion (P = .001). The treatment method-dependent differences in the remission rate were observed in brain lesion and dry eye syndrome (P = .041 and P = .005, respectively). CONCLUSIONS: The most common condition leading to filamentary keratitis was a brain lesion, followed by dry eye syndrome and autoimmune disease. The treatment failure rate was statistically significantly low only in patients with filamentary keratitis associated with brain lesions.

Therapeutic effects of three human-derived materials in a mouse corneal alkali burn model.

Purpose: To compare the therapeutic effects of human derivatives in a mouse alkali burn model. Methods: The right eyes of mice were injured using NaOH. After alkali injury, one of the following agents was topically administered for 7 d: human amniotic membrane (hAM) suspension, human umbilical cord serum (hUCS), and human peripheral blood serum (hPBS), or saline. The epithelial defect areas on days 1, 2, and 3 degrees of opacity on days 2, 3, and 7, and corneal neovascularization (NV) areas on day 7 were evaluated. Histologic examination and mRNA expression levels of tumour necrosis factor (TNF)-α, interleukin (IL)-6, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, MMP-8, and MMP-9 were also evaluated on day 7. Results: The epithelial defect areas in the hUCS group were smaller than those in the control and hPBS groups on day 3 (p < .05, respectively). The epithelial defect areas in the hAM suspension group showed smaller than those in the control and hPBS groups on days 1 and 2 (p < .05, respectively). The degrees of opacity were lower in all treatment groups than that of the saline control group on day 7 (p < .05, respectively). Corneal NV areas were not different among groups on day 7 (p = 0.20). The expression levels of TNF-α, IL-6, MMP-8, and MMP-9 mRNA and the infiltration of the inflammatory cells in all treatment groups were lesser than those in the control group on day 7 (p< .05, respectively). Conclusions: All treatments reduced inflammatory reactions and corneal opacity development. Corneal reepithelialization was faster in the hUCS group.

Vision-related quality of life according to location of visual field loss in patients with glaucoma.

PURPOSE: To assess influence of the location of visual field (VF) loss on vision-related quality of life (VRQOL) in patients with glaucoma. METHODS: We included 826 patients with primary open-angle glaucoma (POAG) enrolled in the prospectively designed Life Quality of Glaucoma Patients Who Underwent Treatment (LIGHT) study organized by the Korean Glaucoma Society. We divided the integrated binocular visual field (IVF) into four regions and evaluated the associations between Rasch-analysed 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) and location of the IVF using univariate and hierarchical multivariable linear regression. RESULTS: Mean deviation (MD) of the IVF at superior centre showed the lowest value among the four regions. Multivariable linear regression analysis revealed significant correlation of the composite score and all subscales of the NEI VFQ-25 except ocular pain and near activities at each of four IVF regions. Mean deviation at superior centre showed significant correlation with composite score (R2  = 0.181), near activities (R2  = 0.175), and social functioning (R2  = 0.166); MD at superior periphery showed highest correlation with role difficulties (R2  = 0.137); MD at inferior centre showed highest correlation with driving (R2  = 0.145); and MD at inferior periphery showed significant correlation with distance activities (R2  = 0.214) and dependency (R2  = 0.119). CONCLUSION: Four different regions of the IVF had a similarly important impact on subscales of the NEI VFQ-25 in glaucoma patients. Preservation of the superior field should be considered as much as that of the inferior field for maintaining a good VRQOL in patients with glaucoma.

Factors influencing vision-related quality of life according to glaucoma severity.

PURPOSE: To identify factors influencing vision-related quality of life (VRQOL) according to glaucoma severity. METHODS: A total of 901 patients with varying stages of glaucoma were recruited from the prospectively designed LIGHT (Life Quality of Glaucoma Patients Who Underwent Treatment) study organized by the Korean Glaucoma Society. Participants completed a basic questionnaire collecting socioeconomic status and clinical information, in addition to the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). Subjects were classified by mean deviation (MD) of integrated binocular visual field (IVF) into mild, moderate and severe damage groups. Factors were evaluated for their influence on VRQOL according to glaucoma severity using univariate and multivariable regression models between Rasch-analysed NEI VFQ-25 subscale scores and different variables. RESULTS: The mild, moderate and severe groups contained 720, 111 and 70 patients, respectively; the mean IVF MD in each group was -1.4, -8.5 and -17.9 dB. Significant differences were observed among the three groups with respect to age, IVF MD, visual acuity (VA), education level, income level, number of glaucoma medications prescribed and follow-up period. The most influential factor associated with VRQOL according to glaucoma severity was VA. The VA of the better eye was much more influential on VRQOL than the VA of the worse eye in the moderate and severe defect groups, and the impact of VA on VRQOL was more prominent in advanced glaucoma. CONCLUSIONS: Visual acuity is the most influential factor on VRQOL in patients with glaucoma. Preservation of VA should be strongly prioritized to maintain good VRQOL.

Medical Litigations Associated with Cataract Surgery in Korea.

BACKGROUND: To analyze the results of court rulings about medical litigations related to cataract surgery in Korea. METHODS: We collected 50 anonymized judgements regarding cataract surgery between 2000 and 2016 and analyzed the reasons for the medical litigations, the court rulings, the reasons for compensation, and the amount claimed and finally awarded. RESULTS: Forty-eight litigations (96%) resulted from errors in treatment, and the reasons were as follows: endophthalmitis, dissatisfaction of visual outcome or ocular discomfort, bullous keratopathy or corneal opacity, retinal detachment, glaucoma or vitreous hemorrhage due to the progression of an underlying diabetic retinopathy, and others in order. Two litigations (4%) arose due to errors in diagnosis. Among the 50 final cases, 21 litigations (42%) were decided in favor of the plaintiff, and 29 litigations (58%) were decided against the plaintiff and dismissed. Ten cases awarded damages to the plaintiffs because of a violation of duty of care, and 11 cases awarded damages due to a violation of informed consent. When comparing cases with errors in diagnosis to cases with errors in treatment, there was no significant difference in the relative risk of a defendant's verdict (P = 0.503). The total amount of awarded damages was KRW 439,124,496 (USD 399,204), and the average amount was KRW 20,910,690 (USD 19,010). CONCLUSION: Nearly half of the cases were decided in favor of the plaintiff due to the violation of informed consent. This study's results will be helpful in understanding the results of medical litigations regarding cataract surgery and reducing future lawsuits.

Vision-related Quality of Life in Korean Glaucoma Patients.

PURPOSE OF THE STUDY: The purpose of the study was to evaluate vision-related quality of life in Korean glaucoma patients and to explore the associated factors. METHODS: A total of 907 glaucoma patients were recruited from the prospectively designed LIGHT (Life quality of the glaucoma patient who underwent treatment) study organized by the Korean Glaucoma Society. Basic questionnaire that included items related to socioeconomic status, comorbidity, and lifestyle, and the validated Korean version of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) were collected. The Rasch score, a logit-based interval scale estimate to summarizing the NEI VFQ-25 responses, was calculated. The univariate and multivariable regression models were used to evaluate associations between the Rasch score and variables. RESULTS: The mean patient age was 58.1±14.1 years, visual field mean deviation (VF MD) of the better and worse eyes was -4.92±6.14 and -9.77±8.31 dB, binocular-integrated VF (IVF) MD was -3.55±5.31 dB, respectively. The lower NEI VFQ-25 Rasch score showed a significant association with the presence of other ocular diseases (P=0.020), a high school level of education or less [vs. university (P=0.006), vs. graduate school or higher (P=0.019)], an anxious personality [vs. a moderate personality (P<0.001), vs. a relaxed personality (P<0.001)], the number of glaucoma medications in use (P=0.049), worse eye visual acuity (P<0.001), and IVF MD (P<0.001). CONCLUSIONS: Visual function parameters are important for the vision-related quality of life of Korean glaucoma patients, notably for worse eye visual acuity and IVF MD. However, social factors, self-assessed personality, and treatment-related issues are also substantial predictors of overall life quality.

The height of the posterior staphyloma and corneal hysteresis is associated with the scleral thickness at the staphyloma region in highly myopic normal-tension glaucoma eyes.

AIMS: To evaluate the characteristics of the posterior segments of eyes with high myopia and normal-tension glaucoma (NTG) and identify which ocular factors are most associated with scleral thickness and posterior staphyloma height. METHODS: The study included 45 patients with highly myopic NTG and 38 controls with highly myopic eyes (≤-6D or axial length ≥26.0 mm). The subfoveal retinal, choroidal, scleral thickness and the posterior staphyloma heights were examined from enhanced depth imaging spectral-domain optical coherence tomography and compared between two groups. RESULTS: Highly myopic NTG eyes had thinner subfoveal scleral thickness (473.03±43.75 vs 579.46±75.87 µm, p<0.001) and higher posterior staphyloma (97.80±70.10 vs 62.83±32.01 µm, p=0.027) than highly myopic, non-glaucomatous eyes. Subfoveal scleral thickness was significantly correlated with age, axial length, corneal hysteresis and the posterior staphyloma height of the superior quadrant, the nasal quadrant and the arithmetic mean of four quadrants in highly myopic NTG eyes. Corneal hysteresis (ß=2.694, p=0.015), corneal resistance factor (ß=-2.916, p=0.010) and the posterior staphyloma height of the nasal quadrant (ß=-0.463, p=0.017) were significantly associated with the subfoveal scleral thickness in highly myopic NTG eyes. CONCLUSION: Subfoveal scleral thinning and non-uniform posterior staphyloma were closely related in highly myopic NTG eyes. Corneal hysteresis, corneal resistance factor and the nasal posterior staphyloma height were associated with the scleral thickness.

Significance of corneal biomechanical properties in patients with progressive normal-tension glaucoma.

AIM: To investigate the clinical significance of corneal biomechanical properties assessed using an ocular response analyser in patients with progressing normal-tension glaucoma (NTG). METHODS: In this retrospective study, we included 82 eyes of 82 NTG patients who had been receiving topical anti-glaucoma medications. Patients were allocated to two groups based on the mean value of corneal hysteresis (CH) and the status of progression. The assessment of progression was based on the trend analysis using mean deviation slope. Uni- and multivariable logistic analyses were constructed to identify factors associated with increased odds of progression, including CH, central corneal thickness (CCT), and retinal nerve fibre layer (RNFL) thickness. RESULTS: Forty-six eyes (56.1%) reached the progression criteria. Eyes with progression had lower CCT (530.2±38.6 vs 549.4±38.3 µm, p=0.03), thinner average RNFL thickness (70.6±16.1 vs 82.8±17.4 µm, p<0.01), lower CH (9.4±1.3 vs 10.8±1.4 mm Hg, p<0.01), and lower corneal resistance factor (9.3±1.3 vs 10.4±1.8 mm Hg, p<0.01) than eyes without progression. CH and CCT were significantly correlated (r=0.44, p<0.01). Upon multivariable analysis, CH (ß (B)=0.32 per mm Hg lower, p<0.01) and average RNFL thickness (ß=0.96 per µm lower, p=0.04) remained statistically significant. CONCLUSIONS: Corneal biomechanical properties are correlated and associated with the progression of visual field damage in NTG patients. These findings suggest that CH can be used as one of the prognostic factors for progression, independent of corneal thickness or intraocular pressure.

Comparison of the ocular surface changes following the use of two different prostaglandin F2α analogues containing benzalkonium chloride or polyquad in rabbit eyes.

OBJECTIVE: The aim of this study is to compare the effect of prostaglandin analogues preserved with either 0.015% or 0.001% benzalkoium chloride (BAK); or 0.001% polyquad (PQ) on the ocular surface of rabbit eyes. METHODS: Forty white rabbits were randomized to receive four-times daily instillation of either 0.0015% tafluprost (TF) preserved with 0.001% BAK (TF-BAK); 0.004% travoprost (TR) with 0.015% BAK (TR-BAK) or 0.001% PQ (TR-PQ); or preservative-free artificial tears in one eye for a 4-week period. Tear samples collected from the 40 rabbits were analyzed by enzyme-linked immunosorbent assays (ELISA) to identify the presence of inflammatory cytokines: interleukin (IL)-1ß and IL-6 on day 14. Subsequently, harvested cornea and bulbar conjunctiva were evaluated using light and transmission electron microscopy (TEM). RESULTS: IL-6 was significantly increased in TF-BAK and TR-BAK groups compared to controls and TR-PQ group (p = 0.005); however, IL-1ß level was not significantly different among four groups (p = 0.360). Rabbits treated with TR-BAK showed decreased goblet cell density of bulbar conjunctiva and increased pyknotic change and vacuolization of corneal epithelial cells on light microscopy; similar change occurred but was less severe in TF-BAK group. The TR-PQ group showed similar results as the controls. The destruction of the microvillar architecture of bulbar conjunctiva and cornea was most prominent in the TR-BAK group. CONCLUSIONS: Preservatives included in the anti-glaucoma eye-drops showed different ocular surface changes according to the concentration and type in the rabbits. Prostaglandin analogues preserved with higher level of BAK may cause more harmful effects on the ocular surface than PQ-preserved medications.

Clinical features and glaucoma according to optic disc size in a South Korean population: the Namil study.

PURPOSE: To assess the proportion of glaucomatous eyes based on the association between optic disc (OD) size and its clinical determinants in the resident population of Namil-myon, Central South Korea. METHODS: Of the 1,532 participants in the Namil study, we included 1,410 Koreans (2,734 eyes) with legible fundus photographs in this study. Following the estimation of OD size on the photographs using Image J software, we corrected for image magnification. Associations between the clinical features, such as age, sex, axial length (AL), spherical equivalent (SE), and central corneal thickness, and the estimated OD size were assessed for individual eyes. After adjusting for the influencing factors, the proportion of glaucoma was compared among three categories of measured OD size (small, medium, and large OD groups). RESULTS: After adjusting for the potential confounders using a linear mixed model, age, sex, AL, and SE were correlated with the OD size estimates (P = 0.003, P = 0.029, P < 0.001, and P < 0.001, respectively). The percentage of glaucomatous eyes was 3.77 % in the small disc group, which was higher than in the other groups (P = 0.054). In particular, normal tension glaucoma (NTG) was statistically significantly more frequent in this group (odds ratio = 1.86, P = 0.042). CONCLUSIONS: These results suggest that clinical features such as age, sex, AL, and SE might need to be considered for an accurate evaluation of the OD. In addition, in individuals with a small OD, the presence of NTG must be carefully investigated in the South Korea population.

Measurement of subfoveal choroidal thickness in normal-tension glaucoma in Korean patients.

PURPOSE: To evaluate subfoveal choroidal thickness (CT) in eyes with normal-tension glaucoma (NTG) in patients who were visualized by enhanced depth imaging optical coherence tomography. METHODS: In this observational, comparative case series, subfoveal CT was measured with enhanced depth imaging optical coherence tomography in 35 eyes of normal individuals and 32 eyes of patients with NTG. Subfoveal CT in each eye was analyzed by measuring the vertical distance from Bruch membrane to the innermost sclera layer. RESULTS: The mean subfoveal CT in the normal individual group and the NTG patient group were 300.0±52.7 and 289.5±100.4 µm, respectively. There was no difference in subfoveal CT in the 2 groups (P=0.60). The mean subfoveal CT in all subjects was significantly correlated negatively with age only (P=0.03). CONCLUSIONS: The subfoveal CT does not differ between the eyes of the normal individual group and the eyes in the NTG patient group, suggesting that CT may not play a role in the pathogenesis of NTG.

Overexpression of SPARC in human trabecular meshwork increases intraocular pressure and alters extracellular matrix.

PURPOSE: Intraocular pressure (IOP) regulation is largely unknown. SPARC-null mice demonstrate a lower IOP resulting from increased outflow. SPARC is a matricellular protein often associated with fibrosis. We hypothesized that SPARC overexpression would alter IOP by affecting extracellular matrix (ECM) synthesis and/or turnover in the trabecular meshwork (TM). METHODS: An adenoviral vector containing human SPARC was used to increase SPARC expression in human TM endothelial cells and perfused human anterior segments using multiplicities of infection (MOIs) 25 or 50. Total RNA from TM was used for quantitative PCR, while protein from cell lysates and conditioned media were used for immunoblot analyses and zymography. After completion of perfusion, the anterior segments were fixed, sectioned, and examined by light and confocal microscopy. RESULTS: SPARC overexpression increased the IOP of perfused human anterior segments. Fibronectin and collagens IV and I protein levels were elevated in both TM cell cultures and within the juxtacanalicular (JCT) region of perfused anterior segments. Collagen VI and laminin protein levels were increased in TM cell cultures but not in perfused anterior segments. The protein levels of pro-MMP-9 decreased while the kinetic inhibitors of metalloproteinases, TIMP-1 and PAI-1 protein levels, increased at MOI 25. At MOI 50, the protein levels of pro-MMP-1, -3, and -9 also decreased while PAI-1 and TIMP-1 and -3 increased. Only MMP-9 activity was decreased on zymography. mRNA levels of the collagens, fibronectin, and laminin were not affected by SPARC overexpression. CONCLUSIONS: SPARC overexpression increases IOP in perfused cadaveric human anterior segments resulting from a qualitative change the JCT ECM. Selective decrease of MMP-9 activity is likely part of the mechanism. SPARC is a regulatory node for IOP.

Cytochemical alterations in the rat retina by LPS administration.

LPS-induced inflammation and changes in protein phosphorylation and the JAK-STAT pathway accompanying glial activation after LPS treatment, were followed by analyzing secreted proinflammatory cytokine levels. The administration of LPS caused tyrosine phosphorylation of STAT3 in retinae and induced glial fibrillary acidic protein. (GFAP) from the nerve fiber layer to the ganglion cell layer. Our results suggest that the LPS-induced activation of the JAK2/STAT3 signaling pathway may play a key role in the induction of astrogliosis. However, no significant increase in vimentin, OX-42 or inducible nitric oxide synthase (iNOS) expressions were observed after LPS administration. Sphingosine kinase catalyzes the conversion of sphingosine to sphingosine-1-phosphate (So-1-P), a sphingolipid metabolite that plays important roles in angiogenesis, inflammation, and cell growth. In the present study, it was found that sphingolipid metabolite levels were elevated in the serum and retinae of LPS-injected rats. To further investigate the chronic effect of increased So-1-P in the retina, So-1-P was infused intracerebroventricularly (i.c.v.) into rats using an osmotic minipump at 100 pmol/10 microl h(-1) for 7 days, and was found to increase retinal GFAP expression. These observations suggest that LPS induces the activation of retinal astrocytes via JAK2/STAT3 and that LPS affects So-1-P generation. Our findings also suggest that elevated So-1-P in the retina and/or in serum could induce cytochemical alterations in LPS treated or inflamed retinae.

Changes in retinal neuronal populations in the DBA/2J mouse.

DBA/2J (D2) mice develop a form of progressive pigmentary glaucoma with increasing age. We have compared retinal cell populations of D2 mice with those in control C57BL/6J mice to provide information on retinal histopathology in the D2 mouse. The D2 mouse retina is characterized by a reduction in retinal thickness caused mainly by a thinning of the inner retinal layers. Immunocytochemical staining for specific inner retinal neuronal markers, viz., calbindin for horizontal cells; protein kinase C (PKC) and recoverin for bipolar cells, glycine, gamma-aminobutyric acid (GABA), choline acetyltransferase (ChAT), and nitric oxide synthase (NOS) for amacrine cells, and osteopontin (OPN) for ganglion cells, was performed to detect preferentially affected neurons in the D2 mouse retina. Calbindin, PKC, and recoverin immunoreactivities were not significantly altered. Amacrine cells immunoreactive for GABA, ChAT, and OPN were markedly decreased in number, whereas NOS-immunoreactive amacrine cells increased in number. However, no changes were observed in the population of glycine-immunoreactive amacrine cells. These findings indicate a significant loss of retinal ganglion and some amacrine cells, whereas glycinergic amacrine cells, horizontal, and bipolar cells are almost unaffected in the D2 mouse. The reduction in amacrine cells appears to be attributable to a loss of GABAergic and particularly cholinergic amacrine cells. The increase in nitrergic neurons with the consequent increase in NOS and NO may be important in the changes in the retinal organization that lead to glaucomain D2 mice. Thus, the D2 mouse retina represents a useful model for studying the pathogenesis of glaucoma and mechanisms of retinal neuronal death and for evaluating neuroprotection strategies.

Non-tuberculous mycobacterial keratitis at the interface after laser in situ keratomileusis.

PURPOSE: To describe two cases of bacterial keratitis with atypical mycobacteria after laser in situ keratomileusis (LASIK). METHODS: Two cases of non-tuberculous mycobacterial keratitis occurred in the interface between the stromal bed and flap, 20 days and 14 days after LASIK. The keratitis progressed slowly and worsened after attempts were made to remove the colonies. Mycobacterium fortuitum was confirmed 2 months after initial presentation following culture of the excised flap tissue in one case, and Mycobacterium chelonae was identified by culture of removed material and by RT-PCR with primers in the other case. The patients were treated medically and by surgical flap removal. RESULTS: In the first case, the keratitis was controlled only after removal of the partially melted flap and intensive medical treatment. In the second case, the lesion cleared after 2 months of antibiotics, but after tapering of antibiotics, the infiltrate progressed. Eventually, the keratitis was controlled after removal of the flap. CONCLUSIONS: Non-tuberculous Mycobacterium should be considered as one of the causes of keratitis when presenting as white colonies in the lamellar bed after LASIK. Treatment for 2 months may not be enough to eradicate the infection and excision of the flap may be necessary.