Norlina Ramli

Low nocturnal ocular perfusion pressure as a risk factor for normal tension glaucoma

OBJECTIVES In the absence of raised intraocular pressure (IOP), haemodynamic parameters have been implicated in the development of normal tension glaucoma (NTG). The purpose of this study is to compare 24-hour IOP and haemodynamic parameters in NTG patients and non-glaucoma patients. METHODS This is a cross sectional study involving 72 NTG patients from University of Malaya Medical Centre eye clinic glaucoma registry. The non-glaucoma patients were volunteers selected from eye clinic patients. All enrolled patients underwent 24-hour IOP and blood pressure monitoring via 2-hourly IOP and blood pressure (BP) measurements. All readings were taken in the sitting position during the diurnal period and in the supine position during the nocturnal period RESULTS Comparison of the haemodynamic parameters, the nocturnal mean systolic BP, nocturnal mean diastolic BP and nocturnal mean arterial pressure (MAP) were significantly lower in the NTG group. The systemic ocular perfusion pressures (OPP), diastolic OPP and mean OPP taken at night were also significantly lower in the NTG group. The differences between the groups were still manifest after controlling for age and presence of hypertension. CONCLUSION Our findings show that the nocturnal supine blood pressure parameters (systolic, diastolic and mean) and OPP were significantly lower in the NTG group compared to normals. This may reflect defective autoregulatory mechanisms in NTG patients.

Risk factors for hypotony after transscleral diode cyclophotocoagulation.

PurposeTo evaluate risk factors associated with hypotony after transscleral diode cyclophotocoagulation (TCP) in East Asian patients with intractable glaucoma. MethodsClinical data from 90 eyes of 90 patients who underwent TCP for various indications at Singapore National Eye Centre between 2005 and 2007 were retrospectively reviewed. Baseline intraocular pressure (IOP) was compared with postoperative IOP at 1 month, 3 to 6 months, and 1 year. Mean total energy per session was calculated in Joules and retreatment rates were recorded. Change in visual acuity and number of medications were recorded at 1-year follow-up. Success was defined as percentage of patients achieving an IOP of 5 to 21 mm Hg with or without medications. Hypotony was defined as IOP <5 at the end of 1-year follow-up period. Factors, such as underlying diagnosis, total energy used, age, earlier operations, and retreatment rates, which may influence the development of hypotony were analyzed using univariate analysis. ResultsSuccess was achieved in 54.0% of patients. Mean total energy used was 83.3±31.7 J. Mean pretreatment IOP was 41.8±12.9 mm Hg, which reduced to 20.7±12.1 mm Hg (P<0.001) at 1 month and 17.8±12.9 mm Hg (P<0.001) at 1 year. Sixteen (39.0%) patients developed hypotony. Univariate analysis showed that neovascular glaucoma patients have a significantly increased risk for developing hypotony post TCP (odds ratio=9.17, 95%; confidence interval=1.85-45.36). ConclusionUnderlying diagnosis of neovascular glaucoma is a significant risk factor for hypotony post TCP.

Corneal changes in type II diabetes mellitus in Malaysia.

AIM To compare corneal endothelial structure and central corneal thickness (CCT) between type II diabetics and non-diabetic control patients. To look for correlations between diabetic status and corneal findings. METHODS Hospital-based, observational study. 200 eyes (from 100 type II diabetic patients and 100 controls) were included. Specular microscopy and pachymetry were used to measure endothelial cell density, size, coefficient of variation in cell area, hexagonality as well as corneal thickness. Independent t-tests were used to compare variables between diabetics and controls. Pearson correlation tests were used to evaluate correlations between corneal findings and diabetic status such as duration of diabetes, haemoglobin A1c (HbA1c) level and severity of diabetic retinopathy. RESULTS Endothelial cell density in the diabetic group (2541.6±516.4 cells/mm(2)) was significantly lower than that in the control group (2660.1±515.5 cells/mm(2), P<0.05). The average size of endothelial cells, standard deviation (SD) of cell size and coefficient of variation (CV) of cell area were all significantly higher in diabetics. Hexagonality was significantly lower in diabetics (41.1%±19.6%) compared to non-diabetics (45.2%±20.6%). CCT was higher in diabetics but not significant (P>0.05). Duration of diabetes, HbA1c level and severity of diabetic retinopathy were not significantly correlated with corneal endothelial findings. CONCLUSION Type II diabetes causes a significant alteration in the state of the cornea including reduction in endothelial cell density and increased pleomorphism and polymegathism. Central corneal thickness is unaffected.

Efficacy of medical therapy in the initial management of acute primary angle closure in Asians

PurposeRecent studies have advocated the use of laser iridoplasty or paracentesis in the initial management of patients with acute primary angle closure (APAC). The aim of this study was to ascertain the effectiveness of medical treatment consisting of topical and systemic intraocular pressure (IOP)-lowering agents in the initial management of APAC.MethodsThis was an observational case series of consecutive patients presenting with APAC at a Singapore hospital over 2 years. On diagnosis, all subjects received intravenous acetazolamide followed by oral acetazolamide, topical pilocarpine, timolol, and steroid eye drops. Resolution of APAC was defined as IOP <21 mm Hg with no acute symptoms.ResultsIn all, 134 consecutive APAC subjects were studied. The majority of subjects were Chinese (96.3%) and female (80%), and the mean age was 63.7±9.6 years. The mean presenting IOP was 58±12.7 mm Hg and mean duration of symptoms was 2.8±3.2 days. With medical therapy, APAC attacks resolved within 3, 6, 12, and 24 h in 28 (21.5%), 58 (44.6%), 99 (76.2%), and 116 (89.2%) subjects, respectively. After resolution of APAC, laser iridotomy was performed in 81.6% of the subjects; 16.2% of the subjects underwent cataract extraction. There was failure of resolution of APAC in only 3 subjects (2.2%). No subject suffered any serious side effects as a result of treatment.ConclusionsMedical therapy resulted in resolution of APAC within 12 h in 76.2% of the subjects and within 24 h in 89.2% of the subjects, showing the effectiveness of medical therapy in the initial management of APAC.

Ocular Surface Disease in Glaucoma: Effect of Polypharmacy and Preservatives.

Purpose To evaluate the prevalence of ocular surface disease (OSD) in glaucoma and nonglaucoma subjects using different clinical tests and to determine the effect of number of antiglaucoma medications and preservatives on OSD. Methods This is a cross-sectional, case-comparison study at the Eye Clinic of the University of Malaya Medical Centre, Malaysia, between June 2012 and January 2013. Glaucoma subjects (n = 105) using topical antiglaucoma medications were compared with control subjects (n = 102) who were not on any topical medications. The presence of OSD was assessed using the tear film breakup time (TBUT) test, corneal staining, Schirmer test, and Ocular Surface Disease Index (OSDI) questionnaire grading. Results The prevalence of OSD varied from 37 to 91% in the glaucoma group, depending on the type of clinical test. More subjects in the glaucoma group had corneal staining (63% vs. 36%, p = 0.004), abnormal Schirmer tests (39% vs. 25%, p = 0.049), and moderate OSDI symptoms (17% vs. 7%, p = 0.028). The percentage with abnormal TBUT increased with higher numbers of topical medications and was high with both benzalkonium chloride–containing and preservative-free eye drops (90% and 94%, respectively, both p < 0.001). Benzalkonium chloride was associated with a nearly three times higher odds ratio of showing abnormal OSDI. Conclusions 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.

Ocular Tuberculosis Initially Presenting as Central Retinal Vein Occlusion

A 23-year-old man presented with central retinal vein occlusion. The retinal haemorrhages worsened and signs of retinal vasculitis appeared later as vision dropped from 6/60 to Counting Fingers. No signs of systemic disease were observed. Routine Mantoux test and chest radiograph were negative for tuberculosis. Fundus flourescein angiogram confirmed presence of retinal vasculitis. Both systemic and topical corticosteroid therapy were ineffective. Polymerase chain reaction analysis of vitreous fluid showed presence of Mycobacterium tuberculosis. A full 6-month course of antituberculosis therapy was given and inflammation subsided. Vision improved to 3/60. This is a rare case of ocular tuberculosis without evidence of systemic infection, presenting first as a central retinal vein occlusion.

Proptosis—Correlation and Agreement between Hertel Exophthalmometry and Computed Tomography

ABSTRACT Aim: To determine the correlation and agreement between Hertel exophthalmometry and computed tomography (CT) of the orbits in measuring proptosis. Materials and Methods: 80 patients (40 normal and 40 with proptosis) were recruited for this study. Exophthalmometry were performed on all of them using the Hertel exophthalmometer and CT. Values and correlations between the modalities were analysed with unpaired t-tests, intraclass correlation coefficients (ICC), and Pearson correlation coefficients (PCC). The Bland–Altman method was used to analyse the agreement between the two modalities. Results: Hertel exophthalmometer and CT measurements did not differ significantly (p > 0.05), although exophthalmometry measurements of the normal (14.5 ± 2.2 mm) and proptosis groups (20.5 ± 3.9 mm) were higher than those obtained from CT (13.9 ± 2.4 mm and 20.0 ± 3.7 mm, respectively). ICC for both the Hertel exophthalmometer and CT measurements were both 0.99, indicating high intra-observer reliability and reproducibility. PCC between Hertel exophthalmometer and CT measurements in both normal and proptosis groups were strongly correlated (r = 0.96 and 0.93, respectively, p = 0.01). The 95% limits of agreement (LOA) between Hertel exophthalmometer and CT measurements for the normal and proptosis groups were −0.70 to 1.78 mm and −2.36 to 3.33 mm, respectively. Conclusion: 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.

Darkroom prone provocative test in primary angle closure glaucoma relatives.

Purpose To evaluate ocular biometric parameters and darkroom prone provocative test (DPPT) in family members of primary angle closure (PAC) glaucoma (PACG) patients and to establish any correlation between these biometric parameters and the DPPT response. Methods Seventy-four family members of PACG patients underwent ultrasound ocular biometry, slit lamp biomicroscopy, Goldmann applanation tonometry, fundus examination, and gonioscopy. Lastly, DPPT was performed. Results Of 74 family members examined, 6 (8.1%) were found to have PAC, 8 (10.8%) were PAC suspects, and 60 (81.1%) were unaffected. Of those affected, 4 (66.7%) had a positive DPPT response, whereas 87.5% of the PAC suspects had a positive or a borderline DPPT response. Affected and PAC suspects had the shallowest anterior chamber depth, thickest lens, shortest axial length, and most anteriorly positioned lens. Anterior chamber depth and lens thickness showed a significant correlation with positive DPPT. Conclusions Anterior chamber depth and lens thickness and, to a lesser extent, axial length and lens position were significantly correlated with a positive DPPT response. The ocular biometric risk factors associated with PACG patients are also found in their respective family members who are affected and suspected of having PAC. We suggest a longitudinal study to determine the reliability of DPPT in identifying individuals who are at risk of PAC.

Low nocturnal diastolic ocular perfusion pressure as a risk factor for NTG progression: a 5-year prospective study

ObjectiveTo assess the relationship between baseline intraocular pressure (IOP), blood pressure (BP) and ocular perfusion pressure (OPP), and the 5-year visual field progression in normal-tension glaucoma (NTG) patients.DesignProspective, longitudinal study.MethodsSixty-five NTG patients who were followed up for 5 years are included in this study. All the enrolled patients underwent baseline 24-h IOP and BP monitoring via 2-hourly measurements in their habitual position and were followed up for over 5 years with reliable VF tests. Modified Anderson criteria were used to assess VF progression. Univariable and multivariable analyses using Cox’s proportional hazards model were used to identify the systemic and clinical risk factors that predict progression. Kaplan–Meier survival analyses were used to compare the time elapsed to confirmed VF progression in the presence or absence of each potential risk factor.ResultsAt 5-year follow-up, 35.4% of the enrolled patients demonstrated visual field progression. There were statistically significant differences in the mean diastolic blood pressure (p < 0.05) and diastolic OPP (p < 0.05) between the progressing and the non-progressing group. There was no association between IOP parameters and NTG progression. Multivariable analysis identified low nocturnal DOPP at baseline as a significant predictive risk factor for glaucomatous visual field progression at 5 years. An mmHg decrease in nocturnal DOPP increases the hazard of progression by 1.4 times. Patients with DOPP < 35 mmHg have 2.3-fold higher probability of progressing compared to the patients with DOPP > 43.7 mmHg (log rank = 0.018).ConclusionDiastolic parameters of BP and OPP were significantly lower in the NTG patients who progressed after 5 years. Low nocturnal DOPP is an independent predictor of glaucomatous visual field progression in NTG patients.

Effect of Nocturnal Intermittent Peritoneal Dialysis on Intraocular Pressure and Anterior Segment Optical Coherence Tomography Parameters.

Purpose: To evaluate the effect of nocturnal intermittent peritoneal dialysis (NIPD) on intraocular pressure (IOP) and anterior segment optical coherence tomography (ASOCT) parameters. Systemic changes associated with NIPD were also analyzed. Methods: Observational study. Nonglaucomatous patients on NIPD underwent systemic and ocular assessment including mean arterial pressure (MAP), body weight, serum osmolarity, visual acuity, IOP measurement, and ASOCT within 2 hours both before and after NIPD. The Zhongshan Angle Assessment Program (ZAAP) was used to measure ASOCT parameters including anterior chamber depth, anterior chamber width, anterior chamber area, anterior chamber volume, lens vault, angle opening distance, trabecular-iris space area, and angle recess area. T tests and Pearson correlation tests were performed with P<0.05 considered statistically significant. Results: A total of 46 eyes from 46 patients were included in the analysis. There were statistically significant reductions in IOP (−1.8±0.6 mm Hg, P=0.003), MAP (−11.9±3.1 mm Hg, P<0.001), body weight (−0.7±2.8 kg, P<0.001), and serum osmolarity (−3.4±2.0 mOsm/L, P=0.002) after NIPD. All the ASOCT parameters did not have any statistically significant changes after NIPD. There were no statistically significant correlations between the changes in IOP, MAP, body weight, and serum osmolarity (all P>0.05). Conclusions: NIPD results in reductions in IOP, MAP, body weight, and serum osmolarity in nonglaucomatous patients.