Subnormal Vision Correction for Aphakia*
9
COMPARISON OF UREA AND MANNITOL 247 10. Wise, B. L., and Chater, N.: Effect of mannitol on cerebrospinal fluid pressure: The action of hypertonic mannitol solutions and of urea compared. Arch. Neurol., 4:200, 1961. Π. : Use of hypertonic mannitol solutions to lower cerebrospinal fluid pressure and decrease brain bulk in man. Surg. Forum, 12:398, 1961. 12. Dyar, E. W., and Mathew, W. B.: Use of sucrose preparatory to surgical treatment of glaucoma: A preliminary report. Arch. Ophth., 20:1036, 1938. 13. Bellows, J., Puntenney, I., and Cowen, J.: Use of sorbitol in glaucoma. Arch. Ophth., 20:1036, 1938. 14. Galin, M. A., Baras, I., and Davidson, R.: Electrolyte effects of osmotic agents. In preparation. SUBNORMAL VISION CORRECTION FOR APHAKIA* GERALD FONDA, M.D. Short Hills, New Jersey Patients judge the result of cataract sur- gery by what they can read and many oph- thalmologists do not realize the importance of unusually strong reading additions. The difference between success and failure of a cataract extraction is often a +16D. read- ing addition. The maximum vision produced by cataract surgery can usually be increased to a greater degree of usefulness by a care- ful refraction and by prescribing strong reading additions. For subnormal vision, strong reading additions, particularly in the form of bifocals, have proven the most suc- cessful method for the correction of aphakia and dislocated lenses. CLINICAL REPORTS Summarized in Table 1 is a group of 85 patients with aphakia, three patients with dislocated lenses and one of spherophakia with cataract whom I examined and for whom I prescribed special lenses. Thirty-five patients (39 percent) pos- sessed visual perception only for hand movements or less in one eye. In the other cases when the vision was better than hand * From the Department of Ophthalmology, New York University School of Medicine. This study was aided in preparation by the Ophthalmological Foundation Inc., New York, and the Research De- partment of the New York Association for the Blind. Presented before the New York Society for Clinical Ophthalmology, February, 1962. movements, it was obvious that the patient used only one eye. The great difference between the vision of the two eyes, often associated with a tropia, encourages the pa- tient to fixate with only one eye. Conse- quently, there was only one eye to refract in over 40 percent of the patients. Vision was usually tested using different Snellen charts for each eye at distances of five feet and 10 feet from the patient, and occasionally at other distances as indicated by the numerator of the visual designation. This method gives a more accurate visual acuity. The vision can be converted into a 20-foot designation by multiplying the nu- merator and denominator by the same num- ber, for example: 5 4 20 200 4 800 Glaucoma was diagnosed in 19 cases (21 percent). The incidence might have been higher if the tension had been recorded for all patients. Detachment of the retina was diagnosed in eight cases (nine percent). Seven of the detachments were in the congenital cataract series. The incidence of detachment would probably have been greater had this compli- cation been searched for with greater effort. These figures emphasize a complication in surgery for congenital cataracts when multi- ple needling procedures are employed.
Transcript of Subnormal Vision Correction for Aphakia*
COMPARISON OF UREA AND MANNITOL 247
10. Wise, B. L., and Chater, N.: Effect of mannitol on cerebrospinal fluid pressure: The action of hypertonic mannitol solutions and of urea compared. Arch. Neurol., 4:200, 1961.
Π. : Use of hypertonic mannitol solutions to lower cerebrospinal fluid pressure and decrease brain bulk in man. Surg. Forum, 12:398, 1961.
12. Dyar, E. W., and Mathew, W. B.: Use of sucrose preparatory to surgical treatment of glaucoma: A preliminary report. Arch. Ophth., 20:1036, 1938.
13. Bellows, J., Puntenney, I., and Cowen, J.: Use of sorbitol in glaucoma. Arch. Ophth., 20:1036, 1938. 14. Galin, M. A., Baras, I., and Davidson, R.: Electrolyte effects of osmotic agents. In preparation.
SUBNORMAL VISION CORRECTION FOR APHAKIA*
GERALD FONDA, M.D. Short Hills, New Jersey
Patients judge the result of cataract surgery by what they can read and many ophthalmologists do not realize the importance of unusually strong reading additions. The difference between success and failure of a cataract extraction is often a +16D. reading addition. The maximum vision produced by cataract surgery can usually be increased to a greater degree of usefulness by a careful refraction and by prescribing strong reading additions. For subnormal vision, strong reading additions, particularly in the form of bifocals, have proven the most successful method for the correction of aphakia and dislocated lenses.
CLINICAL REPORTS
Summarized in Table 1 is a group of 85 patients with aphakia, three patients with dislocated lenses and one of spherophakia with cataract whom I examined and for whom I prescribed special lenses.
Thirty-five patients (39 percent) possessed visual perception only for hand movements or less in one eye. In the other cases when the vision was better than hand
* From the Department of Ophthalmology, New York University School of Medicine. This study was aided in preparation by the Ophthalmological Foundation Inc., New York, and the Research Department of the New York Association for the Blind. Presented before the New York Society for Clinical Ophthalmology, February, 1962.
movements, it was obvious that the patient used only one eye. The great difference between the vision of the two eyes, often associated with a tropia, encourages the patient to fixate with only one eye. Consequently, there was only one eye to refract in over 40 percent of the patients.
Vision was usually tested using different Snellen charts for each eye at distances of five feet and 10 feet from the patient, and occasionally at other distances as indicated by the numerator of the visual designation. This method gives a more accurate visual acuity. The vision can be converted into a 20-foot designation by multiplying the numerator and denominator by the same number, for example:
5 4 20
200 4 800 Glaucoma was diagnosed in 19 cases (21
percent). The incidence might have been higher if the tension had been recorded for all patients.
Detachment of the retina was diagnosed in eight cases (nine percent). Seven of the detachments were in the congenital cataract series. The incidence of detachment would probably have been greater had this complication been searched for with greater effort. These figures emphasize a complication in surgery for congenital cataracts when multiple needling procedures are employed.
248 GERALD FONDA
TABLE 1 CORRECTION OF SUBNORMAL VISION IN 89 PATIENTS*
Case Number
1
11
37
41
44
52
81
102
168
275
346
360
386
387
391
405
407
433
510
Diagnosis
Congenital cataracts, aphakia, esotropia
Congenital cataracts, aphakia, microcornea
Congenital cataracts, aphakia, R. glaucoma
Congenital cataracts, aphakia, L. detached retina
Congenital cataracts, aphakia, interstitial keratitis
Congenital cataracts, aphakia, microcornea
Congenital cataracts, aphakia, esotropia
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia, esotropia
Congenital cataracts, aphakia, exotropia
Congenital cataracts, aphakia
Congenital cataracts, aphakia, esotropia
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Best Vision
R. 10 /200+1 L. 10/100+
R. 5/200 L. 5/200
R. H.M. L. 10/100
R. 12/200 L. L. P.
R. 1/300 L. 20/300
R. 10/200 L. 5/200
R. 10/200 L. 10/70
R. 5/100 L. 3/100
R. 10/200 L. 10/100
R. 4/200 L. L.P.
R. 1 0 / 1 0 0 -L. 10 /100+
R. 5/200 L. 5/50
R. 1 0 / 6 0 -L. 1/300
R. 10/200 L. 10/200
R. 10/60 + L. 10/40 +
R. not recorded L. 1 0 / 6 0 -
R. 10 /100+ L. 7/200
R. 2/200 L. 1/200
R. 10/50
L. 1 0 / 2 0 0 -
Type of Correction
R. + 8 add + 7 L. + 9 add + 1 1 (NV)
R. + 1 0 L. + 1 0 (DV)
R. Balance L. +48.00 Aolite
R. + 9 add + 1 1 Ultex B L. Balance
R. Balance L. +25.00 for NV
R. + 1 2 add + 2 0 for NV L. Balance
R. + 8 add + 5 L. + 8 add + 1 0 Ultex B
R. + 1 1 add + 9 for NV L. Balance
R. Balance L. + 1 1 +1.50 X180add +20.00
fo rNV
R. +48.00 doublet L. Dummy
R. + 9 L. + 1 0 + 2 X25 add + 1 0 (2
pairs)
R. No change L. +11.00 add +12 Ultex B
R. + 1 1 add + 1 0 Ultex B L. Balance
R. Balance L. + 1 0 add + 2 0 Ultex A
R. + 9 L. + 7 +1.50 X35 add + 6
Ultex B
R. Balance L. +5.50 + 5 X180 add + 1 0
Ultex A
R. + 9 add +17.00 Ultex B L. Balance
R. + 1 0 + 3 X160 L. + 1 0 + 2 X15
R. +1.25 + 7 5 X165 add + 5 Kryptok
L. Balance
Result
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Failure
Success
Success
Success
Success
Age
32
40
25
21
50
37
27
54
47
29
23
17
11
9
52
28
25
23
37
* See text for description of lenses. DV= Distant vision NV = Near vision Kryptok = A fused bifocal with a flint-glass segment 22 mm. in diameter.
CORRECTION FOR APHAKIA 249
TABLE 1 (Continued)
Case Number
532
626
702
1,057
1,172
1,268
1,438
1,466
8,037
8,608
9,031
9,156
10,606
11,700
13,358
13,775
13,381
14,575
14,797
Diagnosis
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia, esotropia
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia, L. detached retina
Congenital cataracts, aphakia, L. detached retina
Congenital cataracts, aphakia, uveitis R. ophthalmosteresis
Congenital cataracts, aphakia
Congenital cataracts, aphakia, microcornea
Congenital cataracts, aphakia, esotropia
Congenital cataracts, aphakia, glaucoma, L. detached retina
Congenital cataracts, aphakia, esotropia
Congenital cataracts, aphakia, L. esotropia
Congenital cataracts, aphakia, microcornea
Congenital cataracts, aphakia, exotropia
Congenital cataracts, aphakia, esotropia, L. glaucoma
Congenital cataracts, aphakia
Congenital cataracts, aphakia, L. hypotropia
Best Vision
R. 8/200 L. 10/125
R. 10/70+ L. 10/70-
R. 10/70 L. 10/200
R. 10/70 L. 10/100
R. 3/100 L. 4/70
R. 20/100+
L. 2/200
R. 3/200 L. N.L.P.
R. N.L.P. L. 10/100
R. CF L. 5/120
R. 10/200 L. 10/200
R. 10/200 L. 10/160+
R. H.M. L. 18/200
R. 8/150 L. 10/200
R. 10/200 + L. H.M.
R. 10/60 L. H.M.
R. 10/70 L. 10/60
R. 10/120
L. L.P.
R. 3/100 L. 10/70
R. 10/155+ L. 1/200
Type of Correction
R. -2.00 X165 add + 5 L. +50 -1.50 X155 add
+ 11.00 bifocal
R. + 6 +2.50 X160 add +14 L. +5.50 + 1 X180 add + 8
Ultex B
R. +10 add +10 Ultex B L. Balance
R. + 9 L. + 9 add +4 bifocal R. Balance L. +12.00 add +24.00 AOC
mag. bifocal
R. +11 +1.50 X180add +8.00 Ultex B
L. +11
R. +48.00 Aolite L. Balance
R. Balance L. +12 +1.25 X80 add +20
Ultex B
R. + 8 L. + 8 (DV) R. +12 L. +18 (NV)
R. +12 add +24.00 L. +12 add +24.00 AOC mag.
bifocal
R. No change L. + 5 +2 X90 add +16.00
Ultex B
R. No change L. + 5 add +16 Ultex B R. +12 L. +12 add +20 Ultex B R. +7 add +10 Ultex B L. + 5 no bifocal
R. + 6 add +12 Ultex B L. Balance
R. +3.50 + 3 X170add + 9 L. +3.50 +2.50 X15 add + 9
Ultex B
R. +11 + 1 X180 add +16 Ultex B
L. Balance
R. +10 add + 3 L. +9.50 add +20 Ultex B R. +10.00 add +20.00 Ultex B L. Balance
Result
Failure
Success
Success
Success
Success
Failure
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Age
36
28
8
29
27
34
19
44
49
10
22
24
19
27
26
12
24
11
12
250 GERALD FONDA
TABLE 1 (Continued)
Case Number
14,798
15,271
16,065
16,087
16,291
16,798
16,799
16,923
17,074
17,084
17,423
17,798
18,036
18,091
18,199
18,295
18,692
19,085
19,544
Diagnosis
Congenital cataracts, aphakia, esotropia
Congenital cataracts, aphakia, esotropia, R. detachment, glaucoma
Congenital cataracts, aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia, microcornea
Congenital cataracts, aphakia, microcornea
Congenital cataracts, aphakia, microcornea, R. detached retina
Congenital cataracts, aphakia, R. glaucoma, detached retina
Congenital cataracts, aphakia, esotropia, R. glaucoma
Congenital cataracts, aphakia, microcornea
Congenital cataracts, aphakia, microcornea, esotropia
Congenital cataracts, aphakia
Congenital cataracts, aphakia, R. glaucoma
Congenital cataracts, aphakia, alternating exotropia
Congenital cataracts, aphakia, L. esotropia
Congenital cataracts, R. oph-thalmosteresis, L. aphakia
Congenital cataracts, aphakia
Congenital cataracts, aphakia, L. glaucoma
Congenital cataracts, aphakia, R. esotropia
Best Vision
R. 1/200 L. 10/100+1
R. H.M. L. 5/155
R. 5/70 L. 5/100
R. 3/200
L. 1/200
R. N.L.P. L. 10/100
R. L.P. L. 10/100 +
R. N.L.P. L. 5/200
R. N.L.P. L. 10/70
R. 20/60
L. H.M.
R. 10/200 L. 10/80
R. 5/200 L. 5 /200+
R. lè /200 L. 5 / 7 0 +
R. N.L.P. L. 5/100
R. 5/70 L. 5/40
R. 10/50 L. 10/200+
R. N.L.P. L. 20/490
(3/70)
R. 5/70
L. 5/200
R. 5/100 L. 5/30
R. H.M. L. 5/40
Type of Correction
R. Balance L. + 8 add +16.00 Ultex B
R. Balance L. +80.00 Conoid
R. O.U. +12.00 add +24.00 AOC mag. bifocal
R. +12.00 add +24.00 AOC mag. bifocal
L. Balance
R. Balance L. +7.50 +1.50 X 7 5 a d d
+ 16.00 AOC mag. bifocal
R. +11.00 add + 8 L. + 1 1 +2.50 X 5 a d d + 8 A O C
mag. bifocal
R. Balance L. +80.00 Conoid
R. Balance L. + 1 + 2 X20 add +10.00
Ultex B
R. +8.50 +3.50 X15 add + 5 bifocal
L. No change
R. + 1 3 add +10.00 L. + 1 5 add +10.00 Ultex B
R. +48.00 L. +48.00 Aolite
R. No change L. +10.50 +1.50 X70 add
+ 16.00 Ultex B
R. Balance L. +32.00 Aolite
R. + 9 add +16.00 L. +8.50 + 2 X60 add + 1 6
Ultex B
R. + 6 add + 1 0 L. + 6 add + 1 0 Ultex B
L. +60.00 Conoid
R. +6.50 add + 1 6 AOC mag. bifocal
L. Balance
R. + 7 no bifocal L. + 9 + 2 X180 add + 1 0 Ul
tex B
R. Balance L. + 1 1 . 0 0 add + 6 . 0 0 K r y p t o k
Result
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Success
Failure
Success
Success
Failure
Failure
Success
Success
Age
11
29
12
12
28
47
41
16
63
33
28
10
29
37
16
17
16
14
7
CORRECTION FOR APHAKIA 251
TABLE 1 (Continued)
Case Number
19,697
14
48
49
123
204
229
247
302
400
470
845
900
947
995
1,039
1,372
9,278
12,544
13,107
Diagnosis
Congenital cataracts, aphakia, exotropia
R. ophthalmosteresis, L. aphakia, macular degeneration
Aphakia, R. band keratopathy
R. cataract, L. aphakia
Aphakia, glaucoma
Aphakia and macular degeneration
Pathological myopia, R. aphakia, L. cataract
Healed chorioretinitis, glaucoma, aphakia
Pathological myopia, aphakia
Aphakia, L. glaucoma
Pathological myopia, aphakia, L. detached retina
R. glaucoma, aphakia, L. ophthalmosteresis
Macular degeneration, glaucoma, aphakia
O.U. glaucoma, R. aphakia, L. cataract
R. macular degeneration, aphakia, L. ophthalmosteresis
Myopic degeneration, aphakia
Aphakia, uveitis, glaucoma, optic atrophy
R. cataract, glaucoma, L. aphakia, glaucoma
R. aphakia, macular degeneration, L. cataract
O.U. aphakia, R. Glaucoma, prolapsed iris, L. corneal scar
Best Vision
R. 5/50 +
L. 5 /50+
R. N.L.P. L. 10/200
R. N.L.P. L. 5/70
R. H.M. L. 10/70
R. 10/30 L. 10/70 +
R. 10/70 L. H.M.
R. 10/200
L. L.P.
R. 10/200 L. 1/200
R. 1 0 / 2 0 0 -L. 7/200
R. 10/30
L. N.L.P.
R. 10/80
L. H.M. 2 ft.
R. 10/15
L. N.L.P.
R. 5/200 L. 3/200
R. 10/50 L. 3/100
R. 10/800 L. N.L.P.
R. 10/70 + L. 10/100
R. 10/30
L. 2/200
R. L.P. good L. 20/100
R. 7/150
L. L.P.
R. 2 0 / 5 0 -
L. H.M.
Type of Correction
R. + 1 0 add +16.00 AOC mag. bifocal
L. +9.00
L. +48.00 doublet
R. Balance L. + 7 add +20.00 2 pairs
R. Balance L. + 7 add + 7 Ultex A
R. +9.50 + 4 X180 L. +9.50 + 4 X180 add + 1 1
2 pairs
R. + 1 6 add +12 for NV L. Balance
R. + 4 +1.50 X100 add +22 fo rNV
L. Balance
R. + 7 add + 1 7 L. + 7 2 pairs
R. + 2 6 + 2 XI80 fo rNV L. Balance
R. + 1 1 +1.50 X115 add + 8 Ultex B
L. Balance
R. - 4 + 2 X15 a d d + 1 2 Ultex B
L. Balance
R. + 9 . 7 5 + 3 . 2 5 X15 add + 4 . 0 0 Ultex B
L. Balance
R. + 3 2 . 0 0 Hyperocular L. Balance
R. +35.00 for NV L. Balance
R. + 1 1 . 0 0 for DV L. Balance
R. - 5 + 2 X5 a d d + 1 0 forNV L. - 3 . 5 0 add + 1 0 dec. lenses
in 10 mm. each
R. +3.50 + 3 X180 add +8.00 for NV
L. Balance
R. Balance L. + 9 + 3 X10 add + 9 for NV
R. +11.50 +2.50 X 5 a d d + 16.00 Ultex B
L. Balance
R. + 1 0 + 6 XI75 add +4.50 Kryptok
L. No Change
Result
Success
Failure
Success
Success
Failure
Success
Success
Success
Failure
Success
Success
Success
Success
Failure
Success
Failure
Success
Success
Success
Failure
Age
16
77
57
50
61
40
68
50
70
68
65
69
83
79
68
55
67
90
75
70
252 GERALD FONDA
TABLE l (Continued)
Case Number
13,639
15,606
15,911
18,965
19,435
644
12,687
14,228
1,543
3,852
16,166
16,989
Diagnosis
Aphakia, myopic degeneration
O.U. healed uveitis, R. aphakia, L. esotropia, cataract
Aphakia, R. macular degeneration, L. secondary membrane
Aphakia, R. glaucoma
R. aphakia, L. cataract
Retinitis pigmentosa, R. aphakia, L. cataract
Retinitis pigmentosa, R. cataract L. aphakia
Retinitis pigmentosa, R. cataract, L. aphakia
R. Dislocated lens, glaucoma, aphakia, L. ophthalmostere-sis
Dislocated lenses, esotropia
Dislocated lens
Partial aniridia, congenital cataract, congenital sphero-
phakia, congenital ant. syne-chia, L. glaucoma
Best Vision
R. H.M. L. 5/160
R. 10/70
L. L.P.
R. 10/100
L. 5/200
R. 5/50 L. 3/70
R. 20/200
L. 2/100
R. 10/50
L. H.M.
R. 5/200 L. 20/60
R. 10/137 L. 10/60 +
R. 10/40
L. N.L.P.
R. 5/50 L. 5/100
R. 10/70 L. 10/30-1
R. 2/200 L. 5/70
Type of Correction
R. Balance L. + l 7 + 6 X 1 7 0 N V H a l f e y e
glasses
R. +10.50 +2.50 X10 add + 12.00 Ultex B
L. Balance
R. + 1 0 +2.50 X15 DV +32.00 NV 2 pairs
L. Balance
R. + 1 1 +2.50 X15 L. + 1 2 . 5 0 + 1 . 7 5 X 1 8 0 a d d + 6
O.U. dec. seg. 6 mm. in each Bifocal
R. +10.50 + 2 X155 add + 16.00 AOC mag. bifocal
L. Balance
R. + 1 1 + 1 X 2 0 a d d + 5 bifocal
L. No change
R. Balance L. + 1 1 + 2 X110 add +4.50
Kryptok
R. Balance L. +12.00 +1.50 X100 add
+ 10.00 Ultex B
R. +5.50 X170 add +10.00 Ultex B
L. Balance
R. + 1 1 L. + 1 1 add + 7 Ultex B
R. +9.50 + 1 X105 L. +11.50 +1.25 X80 add
+5.50 Kryptok
R. Blanace L. + 1 3 add + 2 4 AOC mag.
bifocal
Result
Success
Success
Success
Failure
Success
Success
Success
Success
Success
Success
Success
Success
Age
56
73
64
55
78
73
34
34
24
7
23
10
TYPES OF LENSES PRESCRIBED (table 2)
Bifocals, prescribed in 57 cases, were generally one piece, such as Ultex or AOC magnification bifocal.* The strongest read-
* Ultex, a one piece bifocal with segment ground on ocular surface. Ultex B, segment is 22 mm. in diameter; Ultex A, segment is 38 mm. in diameter. AOC magnification bifocal, a one piece bifocal with a segment 25 mm. in diameter, which is available in reading additions of +8.0D., +16D., and +24D. These lenses are made of glass and are not aspheric.
ing addition in a biofocal was + 2 4 diopters. The advantages of a bifocal are: (1) ap-
TABLE 2 TYPE OF LENSES PRESCRIBED
Type Number
Bifocals 57 Single vision (standard lenses) 22 Single vision (best-form lenses) 10 (e. g., doublets, conoid, plastic aspheric)
TOTAL 89
CORRECTION FOR APHAKIA 253
pearance is like that of conventional glasses ; (2) simultaneous vision is possible for distance and near; (3) glasses are lighter than reading lenses, and (4) optical correction is advantageous, because the base-down in the segment neutralizes the base-up in the distant lens.
Standard single vision lenses were supplied in 22 cases. These were made in the form of planoconvex or biconvex. Frequently the curves of the lenses were designated so that the maximum field free of aberration would be obtained by a conventional lens. For example, a +24D. sph. ground with a +6.0D. on the ocular surface and a +18D. on the outside surface provides the clearest field of vision.
Best-form lenses, prescribed for 10 cases, are defined as specially designed lenses to correct spherical and chromatic aberration as well as other optical defects. The best-form lenses used were Aolite* and Hyper-ocular1 (aspheric plastic lenses), Volk Conoid* (aspheric glass lenses) and doublet lenses.1' It should be noted that a special lens (best-form) was required in only 11 percent of these patients. This group required stronger plus than the other patients, because their initial aphakia averaging about + 10D. had been corrected.
Bifocals, standard lenses or best form lenses were preferred to telescopic units. In fact, six patients who had been wearing telescopic spectacles had them changed to one of the above forms. All patients definitely preferred these to telescopic spectacles.
A hand or stand magnifier was rarely prescribed, because the magnification provided by the spectacle lens was more advan-
t Aolite, a plastic aspheric lens for reading at close range, which is available in +32D., +40D., and +48D. (made by American Optical Company).
i Hyperocular, a plastic aspheric lens for reading at close range which is available in +16D., +24D. and +32D. (distributed by I-Gard, Providence, Rhode Island).
* Conoid, an aspheric glass lens (made by American Bifocal Company, Cleveland, Ohio).
t Doublet, consists of two lenses adjacent in a plastic rim.
tageous to the patient. The same magnification in a spectacle provides a field of vision two and one half to three times larger, attracts less attention and leaves both hands free.
FITTING OF LENSES
The optician should fit the bifocal segments so that the top of the segments comes two mm. above the margin of the lower eyelid. Reading additions of +20D. and +24D. should be made with the top of the segment coming up to the lower border of the pupil or to the center of the pupil. Many patients wearing reading additions of +8.0D. and stronger prefer to use the glasses only for reading and resort to distant glasses for general use. However, patients should be encouraged to wear bifocals for constant use unless the reading addition is +20D. or stronger.
The decentration should range from two to five mm. depending upon the relation of the pupil to the geometric center of the lens. This is not of great importance in cases with no binocular vision, because the patient can turn his eye so that his visual axis passes close to the center of the segment.
Generally the reading segment is more readily acceptable to the patient when it is placed on the ocular surface of the lens. The exception to this may be in the AOC magnification bifocals with reading additions of +8.0D., +16D. and +24D. when the distant correction is +3.OD. or less.
Plastic aspheric magnification lenses should be made so that the bottom of the reading spot is located toward the lower border of the lens, because these are for reading and should be set in a position corresponding to a bifocal segment. The patient's visual axis will then more nearly coincide with the optical center of the lens when he is reading.
When instructing the patient, the optician should emphasize repeatedly that the reading material must be held close to the patient's eye in order to read with the new glasses. Most people, particularly the elderly,
254 GERALD F O N D A
TABLE 3 T Y P E OF PATHOLOGY AND RESULTS FOLLOWING CORRECTION OF SUBNORMAL VISION
Type of Pathology No. No. Successful
Percent Successful
Surgical aphakia for congenital cataracts Surgical aphakia for senile cataracts Surgical aphakia for cataracts as complication of retinitis
pigmentosa Dislocated lenses Spherophakia and cataract
TOTAL
58 24 3 3 1
52 17 3 3 1
90 70
89 76
strongly resist reading at close range. The optician should request the patient to return for him to check the adjustment of the glasses. If the glasses are not suitable after the optician's repeated efforts, the patient should be directed to reurn to the ophthalmologist.
RESULTS
A tabulation of the results following the correction of subnormal vision according to the type of pathology appears in Table 3.
The criteria for success were based upon an interview with the patient, generally two or more months after the glasses had been received from the optician. This interval seemed advisable in order to avoid the period of initial enthusiasm.
Evaluation was based upon the answers to the following questions:
1. How long have you been wearing your glasses ?
2. How often do you wear them? 3. How long can you wear them at one
time? 4. For what purposes do you wear the
glasses ? Approximately 90 percent of these cases
were evaluated by me following a personal interview. The accuracy of the prescription, the position and construction of the lenses and the cost of the glasses were checked.
Eighty-five percent of all the corrections were judged to be successful. The patient made only one visit to the ophthalmologist and the average time for a complete ophthalmologic examination was less than 30
minutes. This is reasonable when one considers that more than 40 percent of all patients had only one eye to refract, and that in most cases the ophthalmologist tried only a +8.0D., +16D. or +24D. reading addition beyond the customary +3.0D. sph.
This demonstrates that a subnormal vision correction is only a small extension of a routine refraction. I showed the patient that he must hold the paper two or three inches from his eye when reading. Generally a reading addition was prescribed which was strong enough to enable the patient to read Snellen 0.5 (visual angle one degree, J l ) . The strength of the reading addition was determined by the patient's reading requirements and by his best corrected distant vision.
VISUAL CLASSIFICATION (table 4) Twenty-four patients had vision ranging
between 2/200 and 10/200, and 55 patients had vision ranging between 10/175 and 20/100.
No patient with limited vision and surgical aphakia for congenital cataracts experienced binocular single vision.
SUMMARY AND CONCLUSIONS
Eighty-five patients with aphakia, three with dislocated lenses and one with spherophakia and cataract were corrected for subnormal vision. All were followed for an evaluation of the result. The patient made only one visit to the ophthalmologist and the time spent for a complete ophthalmologic examination was less than 30 minutes.
CORRECTION FOR APHAKIA 2SS
There was only one eye to refract in over 40 percent of cases. The vision was generally tested at distances of five and 10 feet so that the visual acuities would be more accurate. The conventional visual notation is obtained by multiplying both the numerator and denominator by the same number:
5 4 20
50 4 200
Glaucoma was diagnosed in 21 percent of the cases.
Detachment of the retina was diagnosed in eight cases, seven of which were associated with congenital cataracts.
Of the 89 patients with subnormal vision bifocals were used for 57, standard single vision lenses for 22, and best-form lenses for 10 cases.
Bifocals were found to be the preferred method of correction.
A special (best-form) lens was only required in 11 percent of the cases.
No telescopic lenses were prescribed, but telescopic lenses were replaced by single lenses in six cases ; all of these patients preferred single to the telescopic lenses.
A hand or stand magnifier was rarely prescribed, because the same strength lens worn in a spectacle frame increases the field
Plastic aspheric lenses, easily molded to give high powers of magnification, have presented new opportunities to ophthalmologists to help the partially sighted regain their ability to read. This has resulted in gainful employment in many instances,
* From the Low Vision Rehabilitation Center, Pennsylvania Working Home for the Blind. Presented at the 14th annual clinical conference of the Wills Eye Hospital, Philadelphia, February, 1962.
TABLE 4 VISUAL CLASSIFICATION
Visual Classification Number of Patients
2/200- 5/200 8 6/200-10/200 16
10/175-20/200 22 20/175-20/100 33 20/ 80-20/ 30 10
89
of vision two and one-half to three times, attracts less attention and leaves both hands free.
Approximately 90 percent of these patients were interviewed by me. The interview was generally made two months after the optician fitted the glasses. This was done to avoid the period of initial enthusiasm. Strict criteria were used to evaluate the result.
Eighty-five percent of all corrections were judged successful.
In most cases the examiner tried only a + 8.0D., + 1 6 D . or + 2 4 D . reading addition beyond the customary + 3 . 0 D . sph.
A visual classification shows 24 patients had vision ranging between 2/200 and 10/200 while 55 patients had vision ranging between 10/175 and 20/100.
84 Baltusrol Way.
either in a limited or full capacity and, for those unable to work, a form of diversion.
The examination of the partially sighted person is frequently a time-consuming and tedious procedure. From our experience at the Low Vision Center of the Pennsylvania Working Home for the Blind where more than 400 patients with subnormal vision have been examined for optical aids, a method of examination has emerged that will allow
O P T I C A L A I D S F O R T H E P A R T I A L L Y S I G H T E D *
PRACTICAL ASPECTS OF PRESCRIBING
S I D N E Y W E I S S , M.D. Philadelphia, Pennsylvania
