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Industries & Professions /
Ophthalmic Laboratory Technicians
Ophthalmic laboratory technicians may specialize in one activity or perform several functions in the laboratory. There are two major aspects of ophthalmic laboratory work: lens grinding and lens finishing. The work of the lens grinder begins with a standard-size lens blank, which is usually mass produced by an optics company and sold to the ophthalmic laboratory. Following the specifications included in a patient's prescription, lens grinders pick the proper lens blank for the job, measure and mark the lens for grinding and polishing according to the prescription, and set up and operate the machines that grind and polish the lens. They measure the lens with precision instruments, such as lensometers and objective lens analyzers, to make sure that they meet prescribed specifications.
Lens finishers make and cut the lenses and shape, smooth, and bevel (slightly angle) the edges. They then assemble lens and frame parts into finished glasses, using special tools such as lens cutters and glass drills. Finally, they use precision instruments to detect imperfections in the finished product.
Glass cutters lay out and cut glass to specified sizes and weights for molding into lens blanks. They examine the glass stock for defects, trace outlines onto the glass using templates, and grind rough edges from the blank using a grindstone.
Sizers set up the machines that grind and polish the edges and surfaces of lens blanks. They select the specified grinding and polishing tools, adjust the machines according to the size of the lens holders, and set time cycles, which automatically stop the machine after a specified amount of grinding or polishing.
Hand grinders work with the machines that grind the approximate curve onto lens blanks to prepare for the fine grinding. Working from a production order, they choose a lens blank, put the blank in a holder that grips it during grinding, and position the blank and holder on the grinding machine. In order to grind the blank to the specified curvature, they move the control arm of the machine back and forth, or they hold the blank against a grinding wheel.
Precision-lens generators operate and set up the lens-generating machines that grind the ophthalmic blanks. They read work orders to learn the specifications and then pick out specified holders and diamond grinding wheels to do the grinding. They adjust the grinding machine for speed, rate of feed, angle of arc, and depth of cut. After a specified length of time, they stop the machine and measure the curvature and thickness of the glass.
Precision-lens polishers operate the machines that polish the lenses. They mount lenses into holders, apply abrasives, and stop the polishing machine periodically to rinse off the abrasive and to measure the lens to make sure it matches the specifications.
Eyeglass-lens cutters set up and operate bench-mounted cutting machines to cut eyeglass lenses to specified sizes and shapes. They select the metal-cutting pattern according to specifications, mount it in the cutting machine, and press the cutting arm down to cut the lens. They then remove the cut lens, chip away the excess material from the edges, and send the lens on to the workers who do the edging.
Precision-lens centerers and edgers operate grinders to edge and bevel lenses according to work orders. Their work involves a variety of machines, such as truing machines and edge-grinding machines. They must center lenses precisely in these machines using beams of light and other techniques. They start, stop, and adjust the machines and measure the lens edges using micrometers and calipers.
Layout technicians draw reference lines and write specifications onto lens blanks to guide workers who surface or finish lenses. To guide the workers, they locate and mark centers, axis points, and terminal points on lens blanks, using precision instruments such as optical-centering and lens-power-determining instruments that have dials and built-in marking devices. They also examine lens blanks to check for defects and ensure they follow the work order.
Lens mounters place prescription lenses into metal or plastic frames. They inspect lenses for flaws such as pits, chips, and scratches. When possible, they remove the flaws using a grinding wheel and then assemble the eyeglass frame by attaching ornaments, nose pads, and temple pieces.
Multifocal-lens assemblers fit and secure lens parts together for bifocals and trifocals. They clean the surfaces carefully, apply cement, and inspect for any imperfections.
Contact lens blockers and cutters and contact lens lathe operators operate jewelers' lathes and hand tools to cut inside or outside curvature in contact lenses. This job involves a variety of different instruments and lens materials because of the wide variety of contact lenses made available.