Ergonomic Redesign of an Industrial Control Panel.

Operator's role in industrial control centers takes place in time, which is one of the most important determinants of whether an expected action is going to be successful or not. In certain situations, due to the complex nature of the work, the existing interfaces and already prepared procedures do not meet the dynamic requirements of operator's cognitive demands, making the control tasks unnecessarily difficult. This study was conducted to identify ergonomic issues with a specific industrial control panel, and redesign its layout and elements to enhance its usability. Task and link analysis methodologies were implemented. All essential functions and supporting operations were identified at the required trivial levels. Next, the weight of any possible link between the elements of the panel was computed as a composite index of frequency and importance. Finally, all components were rearranged within a new layout, and a computerized mockup was generated. A total of 8 primary tasks was identified, including 4 system failure handling tasks, switching between manual and automated modes, and 3 types of routine vigilance and control tasks. These tasks were broken down into 28 functions and 145 supporting operations, accordingly. Higher link values were observed between hand rest position and 2 elements. Also, 6 other components showed robust linkages. In conclusion, computer modeling can reduce the likelihood of accidents and near misses in industrial control rooms by considering the operators' misperception or mental burden and correcting poor design of the panels and inappropriate task allocation.

Visual function after implantation of aniridia intraocular lens for traumatic aniridia in vitrectomized eye.

PURPOSE: To evaluate the efficacy and safety of aniridia posterior chamber intraocular lens (PCIOL) in traumatic aniridia and aphakia in vitrectomized eyes. METHODS: Four aphakic patients with traumatic aniridia and previous pars plana vitrectomy (PPV) due to posterior segment trauma enrolled in the study, and had secondary implantation of an aniridia PCIOL. Two patients were men and two women with mean age of 39.25 years. Complete ophthalmic examinations, including preoperative and postoperative visual acuity in dark and light, glare disability, visual function (using VF-9 questions modified from VF-14), stereopsis, and contrast sensitivity in 3, 6, 12, and 18 cycle per degree frequencies, were done for all patients. Postoperative intraocular pressure (IOP), IOL centration, and intraocular inflammation were monitored. Mean follow-up was 12.25 months (range 7 to 15 months). RESULTS: Visual acuity improved in all four patients, especially in the light. Glare was subjectively reduced in all of them. Stereopsis was measurable in three of them postoperatively. Contrast sensitivity improved in all patients, especially in brightness and lower frequencies. All four eyes had improved VF-9. All eyes achieved the desired anatomic results. Two cases developed elevated IOP early after surgery. In one eye, IOP elevation was transient and controlled with antiglaucoma medication, but the other eye, which had secondary glaucoma from previous trauma, required cyclophotocoagulation for the IOP to be controlled. No patient developed chronic uveitis or redetachment. CONCLUSIONS: The aniridia PCIOL can overcome aphakia, reduce glare, and increase visual function, contrast sensitivity, and stereopsis in vitrectomized eyes with traumatic aniridia. Although this kind of IOL appears safe, some disadvantages are secondary glaucoma and reduced visibility of peripheral fundus, and caution should be used in its implantation until more patients with longer follow-up are studied.

Biometric indices evaluation in central retinal vein occlusion using partial coherence laser interferometry.

PURPOSE: To evaluate the association of axial length and posterior segment length with central retinal vein occlusion (CRVO) using optical coherence interferometry. METHODS: The study group consisted of 29 patients (13 female and 16 male) with unilateral CRVO who were referred to Farabi Eye Hospital. Patients with macular edema were excluded. The mean keratometry (mean K), axial lengths (AL), anterior chamber depths (ACD), and posterior segment lengths (PSL, defined by AL - ACD) of affected and fellow eyes were measured using optical coherence interferometry. RESULTS: Age range was 45 to 74 years (mean 59.2 +/- 7.5 years). The mean K of affected eyes was not statistically significantly lower than that of unaffected eyes in the CRVO group. This was also true for ACD. Although affected eyes had shorter axial length (23.26 mm vs 23.33 mm), the difference was not significant. There was a statistically significant difference in PSL affected and unaffected eyes (20.15 mm vs 20.26 mm) (p=0.008). CONCLUSIONS: Posterior segment length of eyes with CRVO may be shorter than unaffected eyes. This may predispose them to more crowding of central retinal vein and artery in lamina cribrosa, and developing CRVO.