Challenges in staging and surveillance of patients with neurofibromatosis and cutaneous malignant melanoma.

Malignant melanoma is a skin neoplasm with a rising trend of incidence. Positron Emission Tomography in combination with Computed Tomography (PET-CT) imaging is an essential diagnostic tool for both staging and surveillance of melanoma patients; especially in metastatic disease, where prognosis is poor. We report a case of a patient with known Neurofibromatosis type 1 (NF-1) who presented to the Skin Cancer Multidisciplinary meeting with 11 mm Breslow thickness malignant melanoma of the left forearm. His extensive dermal neurofibromatoses proved a diagnostic challenge to the team. There have been published studies linking NF-1 with malignant melanoma. However the incidence and significance of this has yet to be established. We also discuss the use of PET-CT imaging and skin surveillance in the monitoring and staging of this patient.

Modification, validation and implementation of a protocol for post-thyroidectomy hypocalcaemia.

Introduction The management of post-thyroidectomy hypocalcaemia should facilitate early discharge, and reduce risks of hypocalcaemia, readmission and treatment related hypercalcaemia. This paper describes the implementation, evaluation and revision a protocol for the optimal management of this condition. Methods Day 1 parathyroid hormone (PTH) measurements in addition to calcium measurements were commenced following review of the unit's outcomes and literature on post-thyroidectomy hypocalcaemia. Outcomes from a three-year cohort of patients undergoing thyroid surgery helped amend this protocol (revision 1) to reduce biochemical tests, stipulate the need, nature and dose of vitamin D/calcium supplements, and encourage early discharge. This was further validated over seven months to assess compliance, episodes of hyper and/or hypocalcaemia after discharge, readmissions and need for treatment changes. Further revisions were made (revision 2) and implemented. Results The temporary and long-term postoperative hypocalcaemia rates were 29.1% and 3.2% respectively. Repeat calcium measurements on the first day altered management in only 1.4% of cases. The revised protocol was adhered to in 90% of cases. One patient had hypocalcaemia (due to non-compliance) and one had hypercalcaemia. Revision 2 involved reducing the dose of calcium. Conclusions This is a good example of a unit protocol for post-thyroidectomy hypocalcaemia being developed and modified on the basis of the literature and local experience. Day 1 PTH and calcium levels determine the need for treatment and frequency of follow-up visits, facilitate early discharge, reduce risk of over and/or undertreatment, and are good indicators of permanent hypocalcaemia.

Degree of angle closure and extent of peripheral anterior synechiae: an anterior segment OCT study.

AIMS: To evaluate the relationship between angle width as determined by anterior segment optical coherence tomography (AS-OCT) and the presence of peripheral anterior synechiae (PAS). METHODS: This was a prospective observational case series in which 203 subjects with primary angle closure or open angles were recruited. Images of the nasal, temporal and inferior angles were obtained with AS-OCT in dark conditions. Subjects then underwent gonioscopy by an independent examiner who was masked to the AS-OCT findings. PAS were identified by gonioscopy and defined as abnormal adhesions of the iris to the angle that were at least half a clock hour in width and present to the level of the anterior trabecular meshwork or higher. The total clock hours of PAS were recorded. RESULTS: Sixty-eight subjects (33.5%) were PACS, 76 subjects (37.4%) had PAC/PACG, 14 (6.9%) had primary open angle glaucoma, and 45 (22.2%) subjects were normal with open angles. There was a weak but significant correlation between the angle opening distance (AOD), trabecular iris space area (TISA) and angle recess area (ARA) with clock hours of PAS (Spearman's correlation coefficients = -0.30, -0.32 and -0.32, respectively, p<0.001). The mean values of the AOD, TISA and ARA in the nasal, temporal and inferior quadrants were significantly less in eyes with PAS compared with those without (p<0.001, Mann-Whitney U test). Analysis by quadrant showed that these parameters were smaller in the nasal and temporal quadrants in eyes with PAS (p<0.01). CONCLUSIONS: Angle width determined by AS-OCT and the extent of PAS were weakly correlated, and angle width was significantly smaller in eyes with PAS.

Experience with ARRAY multifocal lenses in a Singapore population.

INTRODUCTION: To evaluate the clinical efficiency, safety and subjective visual outcomes of multifocal intraocular lenses (IOL) in the Singapore population. METHODS: This is a retrospective case series of 45 phacoemulsification with multifocal lens implantation performed in 27 patients for cataracts, over a two-year period. The efficacy, stability and safety of the lens were assessed up to six months of follow-up. A telephone interview enquiring about ratings of vision, spectacle independence, glare, driving difficulty and photic phenomena, was conducted and the results were compared with those published in the literature. RESULTS: The best corrected distance Logmar acuity was 0.1 (0.1 and near visual acuity was N5 (range N5 to N8) at six months. The distance visual acuity stabilised by one month whereas near vision remained unchanged from day one post-surgery. Posterior capsular opacification was seen in 17 patients (38.6 percent) of which two patients (4.55 percent) required YAG capsulotomy. Total spectacle independence was achieved in 12 patients (54.4 percent). Among those who required spectacles, 50 percent required spectacles more than 50 percent of the time. Five patients (22.7 percent) reported glare usually at night (80 percent) as compared with daytime glare (20 percent). The most common photic phenomena report after surgery was halo. CONCLUSION: The Advanced Medical Optics ARRAY multifocal IOL showed good efficacy, predictability, stability and safety. The subjective visual outcomes in the Singapore population were comparable to those of their Western counterparts.

Interocular asymmetry of visual field defects in primary open angle glaucoma and primary angle-closure glaucoma.

AIM: To compare the interocular asymmetry in visual field loss of patients with primary open-angle (POAG) and primary angle-closure glaucoma (PACG). METHODS: Subjects entering a prospective, randomised, controlled trial of intraoperative 5-fluorouracil in glaucoma surgery in Singapore were included. Preoperative visual field testing was performed using automated white-on-white perimetry (24-2 test pattern, threshold program, Mk II, Model 750, Zeiss-Humphrey, San Leandro, CA, USA). A minimum of two tests were required with mean deviation within 2 dB on two tests, fixation losses <20%, false positives <33%, and false negatives <33%. The second field was scored using AGIS II criteria and the 'mean asymmetry score' defined as the mean difference between eyes for both AGIS scores and global indices. RESULTS: In 230 subjects assessed (128 POAG, 102 PACG), mean interocular asymmetry of visual field loss was greater for the PACG group. The mean AGIS asymmetry scores for total (PACG=9.21+/-6.87 vs POAG=6.48+/-5.58, P=0.001), superior (PACG=4.31+/-3.39 vs POAG=3.35+/-3.13, P=0.035), and inferior (PACG=4.43+/-3.31 vs POAG=2.64+/-2.77, P<0.0001) areas and mean deviation (MD) asymmetry scores (PACG=6.89+/-13.22 vs POAG=1.66+/-16.97, P=0.012) were all significantly different. Interocular correlation of visual field loss for POAG was significant; total AGIS, r=0.27 (P=0.003), superior field AGIS, r=0.24 (P=0.008), inferior field AGIS, r=0.34 (P=0.0001), and MD, r=0.27 (P=0.003). In PACG, there was no significant correlation between eyes; total AGIS, r=-0.02 (P=0.85), superior field AGIS, r=-0.02 (P=0.82), inferior field AGIS, r=-0.17 (P=0.87), and MD, r=0.015 (P=0.89). CONCLUSION: There was a greater asymmetry of visual field loss between eyes, as measured by AGIS scores and MD, in PACG than that in POAG.

Effect of cataract extraction and intraocular lens implantation on nerve fibre layer thickness measurements by scanning laser polarimeter (GDx) in glaucoma patients.

PURPOSE: To assess the influence of visually significant cataract on the measurement of nerve fibre layer thickness by scanning laser polarimetry (GDx) in glaucoma patients undergoing phacoemulsification cataract extraction. METHOD AND SUBJECTS: All subjects with primary glaucoma participating in a prospective trial of glaucoma surgery who subsequently underwent cataract extraction were eligible. A single trained observer using the GDx nerve fibre layer analyser (LDT) performed pre- and post-operative measurements of nerve fibre layer thickness (NFLT). NFLT parameters, best-corrected LogMAR visual acuity, and automated visual fields were assessed before and after phacoemulsification cataract extraction with implantation of an acrylic intraocular lens. RESULTS: A total of 49 subjects were assessed: 22 (45%) had POAG and 29 (55%) PACG; all were Asian (36 (73%) were Chinese), with mean age 67.1 (+/-7.6 SD) and mean 'LOCS III' lens opacity grading 11.4 (+/-3.1 SD). Visual acuity significantly improved (mean LogMAR 0.5 vs 0.15, P<0.0001). Corrected pattern standard deviation (6.1 vs 6.4, P=0.2) and mean deviation (-17.7 dB vs -17.0 P=0.91) were little changed after cataract removal. Pseudo-phakic measurements of NFLT were significantly different from pre-op values. Measures of absolute thickness (including the average thickness, ellipse, ellipse average, superior and inferior averages, superior integral) were significantly greater than preoperative values (all P<0.01), whereas ratios and measures of symmetry (symmetry, superior/nasal) were unchanged (all P>0.1) and 'the number' was smaller (P=0.04). Differences in measured NFLT were most strongly correlated with posterior subcapsular cataract (average thickness, P=0.01). CONCLUSIONS: Removal of cataract resulted in greater absolute measurements of NFLT but ratio values were unchanged. Scanning laser polarimetry measurements can change significantly after cataract extraction. New baseline measurements may be required.

Quantitation of mitomycin C in human ocular tissues by high-performance liquid chromatography-photo-diode array detection.

A chromatographic method, which can quantitate mitomycin C (MMC) along with two antiglaucoma drugs, is described. The separation of MMC, alphagan and timolol was performed on a reversed-phase C18 column with water-methanol-trifluoroacetic acid (65:35:0.01, v/v) as the mobile phase. By monitoring at 360, 248 and 296 nm, the lower limits of detection for MMC, alphagan and timolol are, respectively, 1.0, 2.0 and 5.0 ng (injection amount) at three-time S/N ratio. The dynamic ranges of quantitation for the three drugs are, respectively, 1.0 ng-10.0 microg, 2.0 ng-10.0 microg and 5.0 ng-10.0 microg with linearity being larger than 0.9960. This method was applied to the determination of MMC levels in Tenon's and trabeculum tissues of 10 glaucoma patients. MMC levels in these tissues, which were obtained from glaucoma filtering surgery, were determined following a multiple extraction with methanol. The recovery of MMC for a two-batch extraction was better than 91.2%. The reproducibility of measurement for the MMC levels in these tissues is 2.5-6.0% RSD for triplicate injections. The intra-day variation of retention times for the MMC peaks was less than 1.6% RSD (n=3). The inter-day variation of retention times for the MMC peaks was less than 4.8% RSD (n=3). MMC was detectable in three trabeculum tissues out of 10 cases (ranging from 0.8 to 25.5 ng/mg specimen), while MMC was detected in nine Tenon's tissues out of 10 cases (ranging from 0.3 to 21.1 ng/mg specimen). The results obtained show that the method is sensitive and selective for the quantitation of MMC.