261:
88:, incident light must be converging before entering the eye so as to focus on the retina. In this case (the hypermetropic eye) the focus point is behind the retina in virtual space, rather than on the retina screen.
148:
342:
62:, the far point is at infinity, but for the sake of practicality, infinity is considered to be 6 m (20 ft) because the accommodation change from 6 m to infinity is negligible. See
186:
51:. It is sometimes described as the farthest point from the eye at which images are clear. The other limit of eye's accommodation is the
102:
290:
48:
16:
This article is about a measure of an individual's ability to see distant objects as clear and in focus. For other uses, see
17:
386:
366:
256:{\displaystyle P\approx {\frac {1}{\infty }}-{\frac {1}{{\mathit {F}}P}}=-{\frac {1}{{\mathit {F}}P}}}
171:
99:). For example, an individual who can see clearly out to 50 cm would have a far point of
24:
96:
78:
416:
159:
275:
36:
410:
175:
167:
85:
67:
63:
32:
281:
This calculation can be improved by taking into account the distance between the
59:
52:
362:
282:
92:
163:
74:
40:
31:
is the farthest point at which an object can be placed (along the
143:{\displaystyle {\frac {1}{0.5\ {\text{m}}}}=2\ {\text{diopters}}}
337:{\displaystyle P=-{\frac {1}{{\mathit {FP}}-0.015\;{\text{m}}}}}
44:
77:, the far point is closer than 6 m. It depends upon the
314:
311:
242:
217:
293:
189:
105:
336:
285:and the human eye, which is usually about 1.5 cm:
255:
142:
70:for details about 6/6 (m) or 20/20 (ft) vision.
170:at the patient's far point. According to the
95:, the inverse of the distance in meters (see
8:
270:is the distance to the patient's far point.
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326:
310:
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292:
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234:
216:
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196:
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135:
118:
106:
104:
166:by imaging an object at infinity onto a
378:
7:
354:, then the optical power needed is
201:
14:
91:Sometimes far point is given in
35:of the eye) for its image to be
1:
387:"Vision Correction | Physics"
347:For example, if a person has
433:
15:
391:courses.lumenlearning.com
274:is negative, because a
162:can be used to correct
338:
257:
144:
84:For an unaccommodated
73:For an unaccommodated
58:For an unaccommodated
339:
258:
145:
81:of the person's eye.
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187:
103:
334:
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329:
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172:thin lens formula
154:Vision correction
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134:
124:
121:
117:
86:hypermetropic eye
25:visual perception
424:
401:
400:
398:
397:
383:
360:
359:= −3.51 diopters
353:
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318:
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304:
273:
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180:
149:
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132:
125:
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119:
115:
107:
79:refractive error
432:
431:
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422:
421:
407:
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404:
395:
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385:
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348:
308:
289:
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271:
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185:
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160:corrective lens
156:
111:
101:
100:
21:
12:
11:
5:
430:
428:
420:
419:
409:
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403:
402:
377:
376:
374:
371:
369:of one meter.
324:
321:
316:
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307:
302:
299:
296:
283:spectacle lens
276:diverging lens
249:
244:
238:
233:
230:
224:
219:
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208:
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195:
192:
155:
152:
131:
128:
114:
110:
60:emmetropic eye
13:
10:
9:
6:
4:
3:
2:
429:
418:
415:
414:
412:
392:
388:
382:
379:
372:
370:
368:
364:
358:
351:
345:
322:
319:
305:
300:
297:
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286:
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279:
278:is required.
277:
264:
247:
236:
231:
228:
222:
211:
206:
198:
193:
190:
182:
177:
176:optical power
174:the required
173:
169:
168:virtual image
165:
161:
153:
151:
129:
126:
112:
108:
98:
97:Simple myopia
94:
89:
87:
82:
80:
76:
71:
69:
68:Snellen chart
65:
64:visual acuity
61:
56:
54:
50:
49:accommodation
46:
42:
38:
34:
30:
26:
19:
394:. Retrieved
390:
381:
356:
349:
346:
287:
280:
265:
183:
157:
90:
83:
72:
57:
33:optical axis
28:
22:
43:within the
396:2019-12-05
373:References
367:reciprocal
361:where one
75:myopic eye
53:near point
320:−
301:−
232:−
207:−
202:∞
194:≈
29:far point
411:Category
137:diopters
93:diopters
18:Farpoint
365:is the
363:diopter
352:= 30 cm
39:on the
37:focused
417:Vision
266:where
164:myopia
133:
116:
41:retina
27:, the
323:0.015
181:is
113:0.5
66:or
47:'s
45:eye
23:In
413::
389:.
350:FP
344:.
268:FP
263:,
158:A
150:.
55:.
399:.
357:P
328:m
315:P
312:F
306:1
298:=
295:P
272:P
248:P
243:F
237:1
229:=
223:P
218:F
212:1
199:1
191:P
179:P
130:2
127:=
120:m
109:1
20:.
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