[Evaluation of the new Canon HS-100 SD-OCT: Reproducibility of macular ganglion cell complex (GCC) thickness measurement in normal, hypertensive and glaucomatous eyes]

PURPOSE

To evaluate intra- and interobserver reproducibility of macular GCC thickness measurement by automated segmentation on the Canon HS-100 SD-OCT (Tokyo, Japan) in normal (N), hypertensive (OHT) and glaucomatous eyes.

METHODS

A total of 179 eyes of 93 patients were included: 90 N, 28 OHT and 36 early glaucoma and 25 advanced glaucoma. All patients underwent a complete ophthalmologic exam, central corneal thickness and 24-2 standard automated perimetry (HFA SITA standard). Each of two observers performed three macular acquisitions with the Canon OCT HS-100. Acquisitions were analyzed with the Glaucoma 3D mode, which estimated the macular GCC thickness in global, superior and inferior hemisectors, and in eight separate macular areas. Reproducibility was assessed by intraclass correlation coefficient (ICC), coefficient of variation (CV) and test-retest variability (TRTV) calculated as 1.96 times the standard deviation.

RESULTS

Mean GCC thickness was respectively 92.4 μm, 89.0 μm, 80.7 μm and 71.2 μm in N, OHT, early and advanced glaucomatous eyes. In all groups, intra- and interobserver reproducibility ranged respectively for ICC from 89.8 to 99.8% and from 90.2 to 99.4%, for CV from 0.43 to 1.95% and from 0.58 to 2.16% and for TRTV from 0.8 to 3.22 μm and from 1.04 to 3.53 μm. GCC thickness measurements using the new HS-100 SD-OCT were highly reproducible. However, in the advanced glaucoma group, while the reproducibility of GCC thickness measurement is good in the average, superior and inferior hemisectors of the macula, it was slightly less for the paracentral sectors, especially inferior. These sectors correspond generally to the areas most affected by glaucoma.

CONCLUSION

The reproducibility of GCC thickness measurements using the new Canon HS-100 SD-OCT is high for normal, OHT, and glaucomatous eyes. It is thus a reliable and reproducible ancillary test available to the clinician for the examination of glaucomatous optic neuropathies.

[Diagnostic use of macular layer analysis by SD-OCT in primary open angle glaucoma]

PURPOSE

The purpose of this study is to evaluate the diagnostic ability of segmentation of the various internal macular layers by spectral domain optical coherence tomography (Cirrus HD-OCT, Carl Zeiss Meditec (CZM), Dublin, CA, USA) and to compare it to that of the peripapillary retinal nerve fiber layer (cpRNFL) in primary open angle glaucoma (POAG).

MATERIALS AND METHODS

This study included 252 eyes diagnosed with primary open angle glaucoma (POAG) (164 early POAG, 44 moderate POAG and 44 advanced POAG) and 223 eyes of control subjects. All patients underwent visual field testing (Humphrey Field Analyser, SITA-Standard 24-2, CZM), and SD-OCT imaging (Cirrus HD-OCT) of the macular and optic nerve head regions (ganglion cell analysis (GCA), macular cube 200×200; optic disc cube 200×200). OCT macular scans were segmented into macular nerve fiber layer (mNFL), ganglion cell layer with inner plexiform layer (GCIPL), outer retinal layers, and ganglion cell complex (GCC) (mNFL+GCIPL). Glaucoma discriminating ability was assessed using the area under the receiver operator characteristic curve (AUC) for all macular parameters and mean circumpapillary retinal nerve fibre layer (cpRNFL).

RESULTS

For the entire POAG population of this study, the minimum GCIPL index provided greater diagnostic ability than the other parameters studied, with a statistically significant difference in their AUC (minimum GCIPL [0.887], mean GCIPL [0.865], GCC [0.863], cpRNFL [0.823], mean mNFL [0.786] and minimum mNFL [0.742]). The results were similar in the early POAG group but without any statistically significant difference with the cpRNFL parameter. In the moderate POAG group, the diagnostic ability was similar for all indices, whereas in the advanced POAG group, minimum GCIPL and GCC gave the largest AUC indices.

DISCUSSION AND CONCLUSION

The minimum macular GCIPL is a new index obtained with the GCA algorithm of the Cirrus HD-OCT. It appears to have an excellent ability to detect glaucoma at every stage and demonstrates performance comparable to that of the cpRNFL parameter, in combination with which it may provide important complementary information for clinical practice.

Melanoma-associated retinopathy treated with ipilimumab therapy

Melanoma-associated retinopathy (MAR) is a rare autoimmune syndrome in patients with melanoma characterized by visual disorders. MAR is induced by the degeneration of bipolar cells of the retina and the presence of serum autoantibodies against retina proteins. Ipilimumab, an anti-cytotoxic T lymphocyte-associated antigen 4 antibody, improves survival in previously treated patients with metastatic melanoma, but is responsible for a spectrum of immune-related adverse events. Administration of ipilimumab to patients with autoimmune diseases (such as MAR or vitiligo) is actually not recommended. We report a patient presenting with MAR occurring during a melanoma relapse. Surgery and chemotherapy had no effect on visual acuity and melanoma increased. In the absence of alternative antitumoral treatment, we focused on the vital prognosis and treated the patient with ipilimumab. Two years after the treatment the patient is free from new metastasis but has presented with exacerbation of vitiligo and MAR. In the very rare case of melanoma with autoimmune disease without a therapy option, ipilimumab could be discussed, taking into account the fact that it can be effective on tumor burden but can also increase autoimmunity.

[Atypical unilateral glaucoma in a young patient]

BACKGROUND

Diagnostic and therapeutic problems are common in cases of unilateral optical neuropathy with elevated intraocular pressure (IOP) CASE REPORT: A 17-year-old boy was referred for visual acuity loss and elevated IOP at 40mmHg in his left eye. Juvenile open-angle glaucoma (JOAG) was diagnosed based on the clinical and paraclinical examinations. In spite of a maximal hypotensive treatment, tensional control was insufficient and a filtering surgery procedure was necessary. IOP control was good 6 months after surgery, but functional and anatomical analysis showed neuropathic progression and a bilateralization of the disease.

CONCLUSION

The diagnosis of JOAG is difficult and sometimes delayed. Secondary bilateralization commonly causes diagnostic problems which can delay specific and appropriate management. Systematic screening should be performed during infancy when a strong family history of glaucoma is known.

[Analysis of a new visual field index, the VFI, in Ocular Hypertension and Glaucoma]

OBJECTIVE

The Visual Field Index -VFI- is a new perimetric index allowing evaluation of visual function level and progression. In this study, we analysed this new index, that provides a trend analysis of visual field loss progression in Ocular Hypertension and Glaucoma. We also compared results with event analysis.

METHODS

Retrospective study on 94 eyes of 54 patients: 35 OHT(ocular hypertension), 34 early POAG (primary open angle glaucoma) (0>MD>-6 dB), 13 moderate POAG (-6>MD>-12 dB) and 12 advanced POAG (MD<-12 dB), with a mean follow-up of 6.5 years (4 to 8 years). Each subject performed a mean number of 10 standard automated perimetry visual field tests (Humphrey SITA Standard 24-2), excluding tests without reliable indices. VFI progression rate was analysed. VFI progression during the first half period of follow up was compared with that during the second half period. VFI progression was confronted with script alert messages delivered by the last GPA (Guided Progression Analysis) event analysis program.

RESULTS

VFI values were "stable or with low progression" in 100% of OHT patients, 88% of early POAG, 38.5% of moderate POAG, 33% of advanced POAG. Progression during the first half period (mean of 3 years) of follow-up could be extrapolated for the second half period in 97% of OHT patients, 76% of early POAG, 70% of moderate POAG, 75% of advanced POAG. Results from VFI trend analysis and GPA event analysis corresponded in 97% of OHT patients, 85% of early POAG, 85% of moderate POAG, and 87% of advanced POAG.

DISCUSSION

VFI seems to be a useful indicator for glaucoma evaluation and progression follow-up. It completes the event analysis. Some very advanced POAG cannot be analysed by GPA event analysis. VFI should be able to be used for further follow-up. All these results require validation in larger population. The purpose would be to assess if VFI is able to detect different profiles of progression to help treatment decisions.

External radiation exposure and mortality in a cohort of French nuclear workers

OBJECTIVE

To analyse the effect of external radiation exposure on the mortality of French nuclear workers.

METHODS

A cohort of 29 204 workers employed between 1950 and 1994 at the French Atomic Energy Commission (Commissariat à l'Energie Atomique (CEA)) or at the General Company of Nuclear Fuel (COmpagnie GEnérale des MAtières nucléaires (Cogema, now Areva NC)) was followed up for an average of 17.8 years. Standardised mortality ratios (SMRs) were computed with reference to French mortality rates. Dose-effect relationship were analysed through trend tests and Poisson regression, with linear and log-linear models.

RESULTS

The mean exposure to X and gamma radiation was 8.3 mSv (16.9 mSv for exposed worker population). A total of 1842 deaths occurred between 1968 and 1994. A healthy worker effect was observed, the number of deaths in the cohort being 59% of the number expected from national mortality statistics. Among the 21 main cancer sites studied, a statistically significant excess was observed only for skin melanoma, and an excess of borderline statistical significance was observed for multiple myeloma. A dose-effect relationship was observed for leukaemia after exclusion of chronic lymphoid leukaemia (CLL). The relative risk observed for non-CLL leukaemia, n = 20, was 4.1 per 100 mSv (90% CI 1.4 to 12.2), linear model and 2.2 per 100 mSv (90% CI 1.2 to 3.3), log-linear model. Significant dose-effect relationship were also observed for causes of deaths associated with alcohol consumption: mouth and pharynx cancer, cirrhosis and alcoholic psychosis and external causes of death.

CONCLUSION

The risk of leukaemia increases with increasing exposure to external radiation; this is consistent with published results on other nuclear workers cohorts.

MEDOR, a didactic tool to support interpretation of bioassay data after internal contamination by actinides

A didactic software, MEthodes DOsimètriques de REférence (MEDOR), is being developed to provide help in the interpretation of biological data. Its main purpose is to evaluate the pertinence of the application of different models. This paper describes its first version that is focused on inhalation exposure to actinide aerosols. With this tool, sensitivity analysis on different parameters of the ICRP models can be easily done for aerosol deposition, in terms of activity and particle number, actinide biokinetics and doses. The user can analyse different inhalation cases showing either that dose per unit intake cannot be applied if the aerosol contains a low number of particles or that an inhibition of the late pulmonary clearance by particle transport can occur which contributes to a 3-4 fold increase in effective dose as compared with application of default parameters. This underlines the need to estimate systematically the number of deposited particles, as well as to do chest monitoring as long as possible.

Glaucomes. Imagerie de la structure : HRT, GDx et OCT

Confocal scanning laser tomography (HRT), scanning laser polarimetry (GDx VCC), and optical coherence tomography provide quantitative data of the retinal fiber layer and optic nerve head. They have become good complementary evaluation tools for glaucomatous optic neuropathy and their results should be analyzed with clinical data. Good knowledge of the parameters they analyze and their limitations are indispensable. To monitor progression of structural involvement, the analysis programs used need to be validated with prospective clinical studies.

[Practical assessment. Ocular hypertension]

In cases of high intraocular pressure, the patient's hypertension must first be confirmed and its characteristics delineated with a diurnal IOP curve or at least several different measures. Central corneal thickness should be measured, since a thin cornea is a risk factor of progression toward glaucomatous neuropathy. Later, the optic nerve head and retinal nerve fibers should be tested (HRT, GDx, and OCT), to determine whether the ocular hypertension is associated with other findings, and visual field analysis should be carried out (standard automated perimetry, blue-yellow perimetry, FDT), completed by a search for associated risk factors. Therapeutic decisions will be based on this workup, keeping in mind that in the majority of cases, monitoring and information are sufficient but necessary; treatment should, however, be initiated in cases of ocular hypertension with a high risk of progression.

Les lasers diagnostiques dans le glaucome : la polarimétrie à balayage laser (GDx VCC) et la tomographie confocale par balayage laser (HRT)

Automated structural measurements of retinal nerve fibers and optic nerve head are possible with new lasers providing objective and reproductible data for analysis. Scanning laser polarimetry (GDx VCC), based on retardation of polarized light, assesses peripapillary nerve fiber layer thickness. Confocal scanning laser tomography yields precise topographic maps of the optic disc and peripapillary retina. The advantages, applications for glaucoma detection, both in a screening setting as well as for monitoring progression, limitations and pitfalls need to be well known and results should be analyzed with clinical data.

Traitement actuel des glaucomes aigus par fermeture de l’angle

Treatment of acute angle-closure glaucoma is now better adapted for each stage of the disease. The urgent necessity to lower intraocular pressure is normally achieved using medical therapy followed by laser peripheral iridotomy and sometimes by filtration surgery. Early argon laser peripheral iridoplasty is effective and safe in some cases, allowing a very early peripheral iridotomy to be performed and avoiding systemic treatment. When surgery is required, lens extraction must be considered. In all cases, IOP control and regular gonioscopic examination the 1st Year are essential to detect peripheral anterior synechiae.

Cancer mortality among French Atomic Energy Commission workers

BACKGROUND

All causes and cancer mortality of 58,320 workers employed at the Commissariat à l'Energie Atomique (CEA) between 1946 and 1994 were compared with that of the general population in a retrospective cohort study.

METHODS

Standardized Mortality Ratios (SMR) were computed with reference to the French national population.

RESULTS

Between 1968 and 1994, 4,809 deaths occurred. A healthy worker effect is observed for men (SMR = 0.57, CI(90%) = [0.56;0.59]) and for women (SMR = 0.72, CI(90%) = [0.67;0.77]). Nine sites of cancer death were found to be in statistically significant deficit among men, none among women. An excess of pleural cancers is observed among men (SMR = 1.79, CI(90%) = [1.27;2.45]) and of malignant melanoma (SMR = 1.50, CI(90%) = [1.04;2.11]). An excess of breast cancer is observed among women on the borderline of significance (SMR = 1.14, CI(90%) = [0.94;1.37]).

CONCLUSIONS

Excesses observed will have to be related to occupational exposures in the on-going cohort study on French nuclear workers which includes a retrospective exposures assessment.

Epidemiological response to a suspected excess of cancer among a group of workers exposed to multiple radiological and chemical hazards

OBJECTIVE

An excess of cancer was suspected by workers of the metallurgy department at the French Atomic Energy Commissariat (CEA) after several deaths from cancer were reported in 1983 and 1984. After a descriptive study performed by the CEA in 1985 the results of which were not conclusive enough to put an end to the controversy, the present cohort study was undertaken in 1989.

METHODS

As no specific exposure, or a precise cancer site was suspected, it was decided to include all subjects who had worked at the metallurgy department for at least 1 year between 1950 and 1968. The cohort was followed up to 31 December 1990. Individual occupational exposures were determined retrospectively for each year from 1950 to 1990, both qualitatively (annual job, and hazard records, and assistance from former workers) and quantitatively (for external radiation). On the basis of these exposures, three types of occupational tasks were identified: handling of chemicals, radionuclides, and external radiation. Standardised mortality ratios (SMRs) were calculated to estimate the risk of death, and the existence of an association between risk of cancer and each of the three tasks was tested.

RESULTS

The cohort included 356 workers, followed up for an average of 30 years (total of 10,820 person-years). The number of deaths from all causes and from all cancer sites were respectively 44 and 21. No excess of cancer deaths was found for the study period (SMR 0.77), nor was there a peak in 1983-4. The risk of death from all cancer sites increased with the duration of exposure to chemicals.

CONCLUSION

The results do not justify the workers' impression of an excess of cancer. They suggest, however, that the duration of work at some tasks that involved handling chemicals may be an indicator of risk of cancer. Communication to the workers during the study played an important part in reducing their concern, contributing to their better understanding of the results.