Thank you for purchasing the Welsh Allen No. 18200 3,5v halogen streak stereoscope. This instrument has hen designed to meet the needs of today’s practitioners and incorporates features not found on any other retina scope: 1. External Focusing Sleeve—unique planets system allows for easy adjustment no matter hand or how instrument is held. Continuous 360° tailbone Maintains the same plane of focus during rotation. 2.
Introduction Colonoscopy is 3. technique for objective refraction of the eye. There are two basic pes of colonoscopy. Static colonoscopy {described in this booklet is dour with the patient fixating at a distance. Dynamic colonoscopy s done with the patient fixating at 4 near target. These techniques require diligence and expertise that can resulting a precise measurement of the refractive error of an eve, There are two types of serif-lluminated stereoscopes.
The streak stereoscope is found by most practitioners to be easy to use, fast, accurate, and especially valuable in determining the axis of astigmatism, There are several features of the streak stereoscope that make determining the refractive state of the eye easy and accurate, These are: 1. Each meridian can be centralized separately. 2. All errors can be neutralized using ether “with” or “against” motion or perhaps using both, 3. The axis of astigmatism is apparent.
Technique 1. The Operation of the Control Sleeve of the Scope The operator will note that the with of the streak varies as the sleeve is raised and lowered (see Figure 1). When the operating sleeve Is in the lowest position the light rays emitted are sightly divergent. Here the instrument acts with 2 plash mirror effect, which reflects divergent rays that will never come to 1 focus. As the sleeve is raised, the streak focuses.
BY Position yourself 23 meter (26"} from the patient, This distance implies a working lens of +1.50D (computed reciprocal of working distance in meters), Working distance and lens may be varied to slut the practitioner’s needs. (in this instruction book the 2/3 meter (20") working distance is assumed. Different working dimmest can be used, but remember to adjust for our working distance.
) Rotate the control sleeve motile the streak is horizontal and move the streak vertically. The reflex will appear 15 in Figures Big we 5 hligieasipnalig G) I the streak and the reflex move in the chime direction with no lens in the refractive apparatus, the refraction is one of these: 1. Hypertrophy: 2. Metropolitan; 3. Myopia of less than 1,50 adopters. 1f the reflex moves in the opposite direction, the: error is myopia greater than 1.5 adopters. 3.
3. Test for neutralization by one of these methods: it Move the sleeve all the way up {concave mirror position}; the reflex should also appear neutralized; b} Move closer 1 the patient and “with” motion should return; move away amd “against” motion should appear, or o} Place an extra +41.25 sphere in the apparatus and against” motion should appear; 4.
4. interpretation of Results A} Hypertrophy 1. Hypertrophy exists when, af the 2/3 meter distance sing the Plano mirror effect, “with” motion is canalized using 2 plus lens greater than +1.50 adopters and both meridians neutralize with the same strength lens. 2. Total hypertrophy is estimated by subtracting 1.50 adopters from the total strength Tens used. For example, if it ke +2.50 lens to neutralize motion at 2/3 meter, the ital hypertrophy error is +1.00 dippier. B} Myopia 1.
2, Astigmatism can be measured in one of two ways: a3 Neutralize one principal meridian first. Then add the appropriate plus or minus cylindrical Leos dual the other primula meridian is neutralized b} Net fin may also be done by continuing te add spherical lenses until the second principal meridian is neutralized. Then the astigmatic error is equal the difference in strength of lenses necessary to centralize the two meridians. 5.
Other Features designed with the deeps of today’s practitioner in mind. Listed below are several additional features that will increase your diagnostic capability. DYNAMIC Spectroscopy Welsh Allen 3 5v Halogen streak stereoscope can be conditioned with magnetic fiction cards {No. 18230} to help perform dynamic inescapably. In dynamic colonoscopy, the patient is asked to fixate on words, shapes or another age-appropriate target in the plane of or even on the stereoscope itself.
Some arguments presented for sing the spot stereoscope are: 1. When working with pediatric patents, it is important to get the most information in the shortest amount of tme. 'The spot scope, sed on the shape of the reflex, can help detect astigmatism very quickly, Also significant amounts of myopia and hypertrophy can be determined rapidly, 2. For vision screening a large number of patients, e.g. school screenings, the spot stereoscope can help provide more information in a shorter pried of tne. 3.
Instructions for Lamp Replacement No. 18200 Streak Stereoscope {Use only Welsh Allen 3.5+ Halogen Lamp No. 082003 No. 18300 Spot Stereoscope {Use only Welsh Alva 3.5v Halogen Lamp No. 083003 1. Remove stereoscope from power source. 2. Remove lamp: Lift out with nail file, lecher peter or similar instrument winder base flange. CAUTION: Lamp may be hot and should be allowed to cool before removal.
3. Tortoise new Jap: 08200 landline up pin ou damp with slot between the metal electrical contact wires. Push damp into receptacle as far as twill go. Tot Electrical contact wires 8300 lamp into receptacle as far as it will go, Lamp should insert easily—do not force. Lap base contact pin should be even with metal cutouts in stereoscope bus. 4. Replace retina scope an power soiree The No. 18200 and No. 18300 are essentially the same Instrument, The No.
Técnica L. La operación del manguito de control del estereoscopio ¥ operador observar que el ancho de la franja varga a medida que ef manguito se sabe o baja {vea Ia figura 1). Cuando el manguito de operación estad en su posición mas baja, los rayos de Tuz emitidos son levemente divergentes. Aquí ¢f instrumente acta con un efecto de espejo plano, ef cual refleja los rabos divergentes que nunca Denegar @ estar enfocados. A medida que se levanta el manguita, I8 faja se enfoca.
B} Colóquese a (.67 metros (267} del paciente, Asta distancia implica Entes de trabajo de + 150D (se calen la como lo reciproco de fa distancia de trabajo en metros}, Ta distancia de trabaje v las lentes pueden variar para ajustarse a las necesidades dwl especialista. (Fn este libro de instrucción se supone ung distancia de trabajo de 5,67 metros (267). Pueden utilizarse diferentes distancias de abajo, pero recuerde ajustar seguir su distancia de bocabajo.
. El astigmatismo puede medirse en una de dos formas: @ Neutralizando un meridiano principal primero. Luego agregando ¢l ente cilíndrico adecuado mas o menos hasta que se neutralice ¢ otro meridiano principal. by Racionalizan también puede realizarse si se contunda agregando lemes esféricas usa que ¢ segundo meridiano principal se neutralice, Entonces el fervor estigmatice ex igual & I diferencia de intensidad de lentes necesarios par neutralizar los das meridiano: 5.