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Two looks at the choyce lens
two looks at the choyce lens John Sheets, M.D. Odessa Texas
A physician is able to make future decisions only in the light of his past results. If he is honest with himself he periodically reviews his capabilities and statistical results. Without self criticism one might continue in practice oblivious of his errors. One does not need hundreds of cases in order to decide as to which is in the best interest of future patients. It is with these ideas in mind that this author reviewed the results of the use of the Choyce Mark VIII lens over the past fifteen months. It might be shown that where the following statistical evaluation points out problems with a Choyce lens, it was the result of surgical technique. The author would have no quarrel with those who might be able to point out errors in surgical technique and would instead welcome them. However, to the best of my knowledge, the author has followed the techniques as closely as possible to those who are considered experts in this implantation method (and the following are the results obtained by this author). This review includes seventy-four cataract extractions followed by an implantation of a Choyce Mark VIII lens. Of these, forty-eight were intracapsular extractions, fourteen extracapsular extractions with an open posterior capsule, and twelve extracapsular extractions with posterior capsule intact. The Choyce lenses produced were fifty by Rayner and twenty-four by McGhan Medical. Statistical evaluation showed no significant difference between the two lenses used. Of the Rayner Mark VIII lenses there were sixteen of the fifty with less than 20/40 vision and of the McGhan Medical Choyce lens there were nine out of twenty-four with less than 20/40 vision. There were no cases of hypopyon or warped feet on any of the patients. Other statistics noted are shown in the following charts. VITREOUS LOSS Intracapsular Patients Extracapsular Patients
2 6
4.2% 23.1%
Total-
8
10.8%
It is noted that the extracapsular cataract extractions showed a very high percentage of vitreous loss. The explanation for this is that during a period of time the Choyce lens was used in those cases being performed by phacoemulsification in which vitreous loss occurred. This represents (some) several hundred patients done by phacoemulsification of which six had vitreous loss followed by a Choyce lens implantation. It was also likewise used in a number of cases in which the posterior capsule was ruptured without vitreous loss which should basically be equivalent to an intracapsular extraction. POST OP PAIN - Longer than 4 months 22 patients -
29.7%
ANY SIGNIFICANT POST OP HEMORRHAGE 16 patients 21.6% CYSTIC MACULAR EDEMA - Longer than 4 months 14 patients -
18.9%
RETINAL DETACHMENTS 5 patients == 6.8% (2 by Intracap, 3 by Extracap)
3 had vitreous loss
VISION (4 to 15 months Post Op) 20/40 or better 20/50 or worse -
48 patients 26 patients -
64.9% 35.1%
VISUAL ACUITY ELIMINATING PRE-EXISTING CONDITIONS 20/40 or better -
48 patients -
72 %
It is the final results that help one in determining future procedures. The author has performed over two thousand cataract extractions with lens implantation using various lenses and techniques of extraction. In our hands it is noted that with the Choyce lens, final visual results are fifteen to twenty percent less than with any other lens that has been used with any means of extraction of the cataract. When one obtains less good results than another
213
surgeon, using similar techniques, the surgeon with the lesser results should seek out the problems that are producing these possible difficulties. To date the author has not found specific differences; however, there has turned out to be one saving grace for this surgeon to maintain "face". To date we have done approximately fifty secondary implantations of intraocular lenses (which is obviously a very conservative number of patients, considering the total number of implantations performed). We feel that it has been extremely important to be highly selective in secondary implantations. The total results on secondary implantations have been so successful that it is probably time for us to re-evaluate the performance of such procedures. However, apropo to this particular paper, the author has done fourteen secondary implantations of the Choyce Mark VIII lens. Because of the results on these cases, the author feels that perhaps he does know how to put in a Choyce lens, otherwise higher problems would have resulted. The following chart shows the number of post-operative complications occuring in these fourteen patients. 14 Secondary Choyce Implants Pain Hemorrhage CME V. Loss R.D. Number Pts. Percent
1 7.1
2 14.2
1 7.1
1 7.1
1 7.1
Corneal Edema 0 0
14 Secondary Choyce Implants Visual Acuity (4 to 15 months) >20/40 <20/40
10 4
71.4% 28.6%
Visual Acuity Eliminating Pre-Existing Conditions >20/40 <20/40
10
1
91 % 9
%
It has to be obvious that one surgeon performing the surgery primarily and secondarily must have similar skills. The only conclusion that can be reached from the numbers presented above (albeit they are relatively small numbers) is that there is certainly a difference in the condition of the eye undergoing primary implant of a Choyce lens. It is not the scope of this paper to be able to point out specifically what these differences are but hopefully it will stimulate discussion and study into what that difference might
214
be. The quality or structure of the vitreous apparently must undergo definite changes post cataract surgery and it would appear possible that these changes occur about the time that macular edema ceases to exist in an eye having undergone cataract extraction. Re-evaluating ones capabilities and statistics also permits one to theorize, but all too frequently does not allow him to come to final conclusions as to the reasons for problems. We all hope that someone will find the simple answers.
A physician is able to make future decisions only in the light of his past results. If he is honest with himself he periodically reviews his capabilities and statistical results. Without self criticism one might continue in practice oblivious of his errors. One does not need hundreds of cases in order to decide as to which is in the best interest of future patients. It is with these ideas in mind that this author reviewed the results of the use of the Choyce Mark VIII lens over the past fifteen months. It might be shown that where the following statistical evaluation points out problems with a Choyce lens, it was the result of surgical technique. The author would have no quarrel with those who might be able to point out errors in surgical technique and would instead welcome them. However, to the best of my knowledge, the author has followed the techniques as closely as possible to those who are considered experts in this implantation method (and the following are the results obtained by this author). This review includes seventy-four cataract extractions followed by an implantation of a Choyce Mark VIII lens. Of these, forty-eight were intracapsular extractions, fourteen extracapsular extractions with an open posterior capsule, and twelve extracapsular extractions with posterior capsule intact. The Choyce lenses produced were fifty by Rayner and twenty-four by McGhan Medical. Statistical evaluation showed no significant difference between the two lenses used. Of the Rayner Mark VIII lenses there were sixteen of the fifty with less than 20/40 vision and of the McGhan Medical Choyce lens there were nine out of twenty-four with less than 20/40 vision. There were no cases of hypopyon or warped feet on any of the patients. Other statistics noted are shown in the following charts. VITREOUS LOSS Intracapsular Patients Extracapsular Patients
2 6
4.2% 23.1%
Total-
8
10.8%
It is noted that the extracapsular cataract extractions showed a very high percentage of vitreous loss. The explanation for this is that during a period of time the Choyce lens was used in those cases being performed by phacoemulsification in which vitreous loss occurred. This represents (some) several hundred patients done by phacoemulsification of which six had vitreous loss followed by a Choyce lens implantation. It was also likewise used in a number of cases in which the posterior capsule was ruptured without vitreous loss which should basically be equivalent to an intracapsular extraction. POST OP PAIN - Longer than 4 months 22 patients -
29.7%
ANY SIGNIFICANT POST OP HEMORRHAGE 16 patients 21.6% CYSTIC MACULAR EDEMA - Longer than 4 months 14 patients -
18.9%
RETINAL DETACHMENTS 5 patients == 6.8% (2 by Intracap, 3 by Extracap)
3 had vitreous loss
VISION (4 to 15 months Post Op) 20/40 or better 20/50 or worse -
48 patients 26 patients -
64.9% 35.1%
VISUAL ACUITY ELIMINATING PRE-EXISTING CONDITIONS 20/40 or better -
48 patients -
72 %
It is the final results that help one in determining future procedures. The author has performed over two thousand cataract extractions with lens implantation using various lenses and techniques of extraction. In our hands it is noted that with the Choyce lens, final visual results are fifteen to twenty percent less than with any other lens that has been used with any means of extraction of the cataract. When one obtains less good results than another
213
surgeon, using similar techniques, the surgeon with the lesser results should seek out the problems that are producing these possible difficulties. To date the author has not found specific differences; however, there has turned out to be one saving grace for this surgeon to maintain "face". To date we have done approximately fifty secondary implantations of intraocular lenses (which is obviously a very conservative number of patients, considering the total number of implantations performed). We feel that it has been extremely important to be highly selective in secondary implantations. The total results on secondary implantations have been so successful that it is probably time for us to re-evaluate the performance of such procedures. However, apropo to this particular paper, the author has done fourteen secondary implantations of the Choyce Mark VIII lens. Because of the results on these cases, the author feels that perhaps he does know how to put in a Choyce lens, otherwise higher problems would have resulted. The following chart shows the number of post-operative complications occuring in these fourteen patients. 14 Secondary Choyce Implants Pain Hemorrhage CME V. Loss R.D. Number Pts. Percent
1 7.1
2 14.2
1 7.1
1 7.1
1 7.1
Corneal Edema 0 0
14 Secondary Choyce Implants Visual Acuity (4 to 15 months) >20/40 <20/40
10 4
71.4% 28.6%
Visual Acuity Eliminating Pre-Existing Conditions >20/40 <20/40
10
1
91 % 9
%
It has to be obvious that one surgeon performing the surgery primarily and secondarily must have similar skills. The only conclusion that can be reached from the numbers presented above (albeit they are relatively small numbers) is that there is certainly a difference in the condition of the eye undergoing primary implant of a Choyce lens. It is not the scope of this paper to be able to point out specifically what these differences are but hopefully it will stimulate discussion and study into what that difference might
214
be. The quality or structure of the vitreous apparently must undergo definite changes post cataract surgery and it would appear possible that these changes occur about the time that macular edema ceases to exist in an eye having undergone cataract extraction. Re-evaluating ones capabilities and statistics also permits one to theorize, but all too frequently does not allow him to come to final conclusions as to the reasons for problems. We all hope that someone will find the simple answers.