Ocular surface disease is common in those using topical antiglaucoma medications. Abnormal TBUT is associated with increasing number of eye drops and benzalkonium chloride-containing eye drops, although this also occurs with the use of preservative-free eye drops.

Although Hertel exophthalmometer and CT measurements are similar and strongly correlated, they do not agree well with each other in the presence of proptosis. The measurements should not be used interchangeably as the differences between them may lead to errors in clinical interpretation.

BackgroundAltered levels of specific matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in the aqueous humour of primary open-angle glaucoma (POAG) eyes have been described. In this study, levels of specific MMPs and TIMPs in the aqueous humour of primary angle-closure glaucoma (PACG) eyes were measured and compared with those of POAG as well as non-glaucoma control eyes.MethodsAqueous humour from 16 PACG, 28 POAG and 27 control eyes were sampled during intraocular surgery. Levels of total protein, MMP-2, MMP-3, TIMP-1 and TIMP-2 were quantified by protein assay and enzyme immunoassay.ResultsTotal protein levels were significantly higher in PACG (0.426 ± 0.126 mg/ml, p = 0.043) and POAG (0.578 ± 0.360 mg/ml, p = 0.007) compared to controls (0.292 ± 0.192 mg/ml). The difference between PACG and POAG was not significant (p = 0.158). MMP-2 was significantly higher in PACG (p = 0.032) and POAG (p < 0.001) compared to controls. The difference between PACG and POAG was also not significant (p = 0.133). MMP-3 was significantly higher in POAG compared to controls (p = 0.002) and PACG (p = 0.029). The difference between PACG and controls was not significant (p = 0.962). TIMP-1 was significantly higher in PACG (p = 0.049) and POAG (p = 0.010) compared to controls. The difference between PACG and POAG was also not significant (p = 0.961). TIMP-2 was significantly higher in POAG (p = 0.004) compared to controls. The difference between PACG and either controls or POAG was not significant (p > 0.05). Although not statistically significant (p > 0.05), the MMP-2/TIMP-2 ratio was highest in PACG (2.83 ± 7.40), followed by POAG (1.38 ± 1.55) and controls (1.34 ± 3.05). Similarly, the MMP-2/TIMP-1 ratio was highest in PACG (1.50 ± 1.69), followed by POAG (1.40 ± 0.77) and controls (1.15 ± 0.92). The MMP-2 + MMP-3/TIMP-1 + TIMP-2 ratio was higher in PACG (0.83 ± 0.80) and POAG (0.82 ± 0.53) compared to controls (0.70 ± 0.63). In both POAG and PACG, there were no significant differences in the levels of total protein, MMP-2, MMP-3, TIMP-1 and TIMP-2 between patients on prostaglandin analogues and those not.ConclusionWe found altered levels of MMPs and TIMPs as well as imbalance of MMP:TIMP ratios in the aqueous humour of PACG eyes that were different from POAG and non-glaucoma control eyes.

In vertebrates, intraocular pressure (IOP) is required to maintain the eye into a shape allowing it to function as an optical instrument. It is sustained by the balance between the production of aqueous humour by the ciliary body and the resistance to its outflow from the eye. Dysregulation of the IOP is often pathological to vision. High IOP may lead to glaucoma, which is in man the second most prevalent cause of blindness. Here, we examine the importance of the IOP and rate of formation of aqueous humour in the development of vertebrate eyes by performing allometric and scaling analyses of the forces acting on the eye during head movement and the energy demands of the cornea, and testing the predictions of the models against a list of measurements in vertebrates collated through a systematic review. We show that the IOP has a weak dependence on body mass, and that in order to maintain the focal length of the eye, it needs to be an order of magnitude greater than the pressure drop across the eye resulting from gravity or head movement. This constitutes an evolutionary constraint that is common to all vertebrates. In animals with cornea-based optics, this constraint also represents a condition to maintain visual acuity. Estimated IOPs were found to increase with the evolution of terrestrial animals. The rate of formation of aqueous humour was found to be adjusted to the metabolic requirements of the cornea, scaling as , where Vac is the volume of the anterior chamber. The present work highlights an interdependence between IOP and aqueous flow rate crucial to ocular function that must be considered to understand the evolution of the dioptric apparatus. It should also be taken into consideration in the prevention and treatment of glaucoma.

Aims To study the effect of haemodialysis on intraocular pressure (IOP) of patients at the University Malaya Medical Centre, Kuala Lumpur, and the influence of anterior chamber angles, surgery, and diabetes on the change in IOP after haemodialysis. Methods Prospective, single centre study on patients undergoing haemodialysis with a sample size of 98 eyes (49 patients). Ocular examination was performed before haemodialysis. Pre-and post-haemodialysis IOP measurements were taken. Plasma osmolarity changes and volume of fluid removed were noted. Patients on antiglaucoma treatment or who have had earlier laser or surgical procedures for it were excluded. Student's t-test and Pearson's coefficient test were used to determine the statistical significance. Results Plasma osmolarity decreased significantly (À11.6 ± 10.0mOsm/l, Po0.001). In eyes with occludable angles (8% of cases), IOP decreased significantly (À3.63 ± 1.92 mmHg, Po0.001). In non-occludable angle eyes (92% of cases), no significant changes (P40.05) in all subgroups of non-operated/operated and diabetic/ non-diabetic eyes were seen. Conclusions Haemodialysis does not cause significant changes in IOP in non-glaucomatous and non-occludable angle eyes.

Therapy-resistant P. aeruginosa keratitis acquired from the community is becoming an increasing problem. Topical piperacillin/tazobactam is an option for the treatment of therapy-resistant P. aeruginosa keratitis.

SIGNIFICANCE To our knowledge, this is the first time a study looking at the association between subfoveal choroidal thickness (SFCT) and the parameters affecting the severity of pre-eclampsia has been reported. We provide evidence that SFCT is thicker in pre-eclamptic (PE) patients and speculate on the possible causes. PURPOSE The purposes of this study were to compare SFCT in PE, normal pregnant, and nonpregnant women using spectral domain optical coherence tomography and to correlate SFCT with severity of pre-eclampsia. METHODS A cross-sectional, observational study was performed. A total of 150 participants were divided into three groups: group 1 (50 PE women), group 2 (50 normal pregnant women), and group 3 (50 nonpregnant healthy women). Subfoveal choroidal thickness was measured using spectral domain optical coherence tomography. Other parameters including mean arterial blood pressure (MABP), central corneal thickness, macular thickness, IOP, ocular perfusion pressure (OPP), and urine protein-to-creatinine ratio were also measured. ANOVA and Pearson correlation analysis were used to look at differences between the groups. P < .05 was considered as statistically significant. RESULTS The MABP was higher in group 1 than in groups 2 and 3 (103.0 ± 12.9 vs. 83.2 ± 9.8 vs. 89.5 ± 7.2 mmHg, respectively; all P < .001). The SFCT of the PE group was higher than in groups 2 and 3 (370.7 ± 23.8 vs. 344.5 ± 30.8 vs. 315.8 ± 49.9 μm, respectively; all P < .001). There were no statistically significant differences in central corneal thickness, macular thickness, or IOP between the PE and healthy pregnant groups (all P > .05). The OPP was greater in PE patients (52.8 ± 8.5 vs. 41.9 ± 6.9 vs. 43.4 ± 5.2 mmHg, respectively; both P < .001). The SFCT was positively correlated with MABP (r = 0.464, P < .001), OPP (r = 0.495, P < .001), and urine protein-to-creatinine ratio (r = 0.635, P < .001) in the PE group. CONCLUSIONS Subfoveal choroidal thickness is higher in pre-eclampsia and is proportional to established markers of severity of the condition. This parameter might serve as a novel predictive marker for the severity of pre-eclampsia.

BackgroundVascular insufficiency has been reported to be a cause of normal tension glaucoma (NTG). The aim of this study was to compare ocular perfusion pressure (OPP) and ophthalmic artery flow (OAF) between patients with NTG and those without glaucoma.MethodsWe considered one eye each from 31 NTG and 15 non-glaucoma control patients. Blood pressure and intraocular pressure (IOP) were measured in the sitting position, for calculation of OPP. Humphrey visual field (HVF) assessment was then carried out on NTG patients. All patients then underwent Transcranial Doppler ultrasound measurements of OAF parameters, including mean flow velocity (MFV), end diastolic velocity (EDV), peak systolic velocity (PSV) and resistive index (RI). We looked at differences in OPP and OAF parameters between the two groups, and their correlations in NTG patients. T-tests, χ2, ANOVA and Pearson Correlation tests were performed, with p < 0.05 considered statistically significant.ResultsThere were no statistically significant differences in OPP between the NTG and control groups (60.5+/-8.7 mmHg and 62.9+/-10.2 mmHg respectively, p = 0.393), and also no statistically significant differences in MFV, EDV, PSV and RI (all p > 0.05). In the NTG group, there were positive correlations between OPP and both MFV (r = 0.416, p = 0.020) and EDV (r = 0.369, p = 0.041). There were no statistically significant correlations between HVF mean deviation and OPP or OAF parameters (all p > 0.05).ConclusionThere is no difference in OPP and OAF parameters between patients with NTG and non-glaucoma controls, suggesting that vascular insufficiency or dysregulation by themselves may not account for the pathogenesis of NTG.