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Secondary Intraocular Lens Implantation vs Epikeratophakia for the Treatment of Aphakia
Secondary Intraocular Lens Implantation vs Epikeratophakia for the Treatment of Aphakia Daniel S. Durrie, M.D., Diana L. Habrich, M.D., and Thomas R. Dietze, M.D. We analyzed retrospectively the results of 30 consecutive secondary intraocular lens im plantations and 30 epikeratophakia proce dures performed by one surgeon for adult aphakia. Specific indications for epikerato phakia were criteria that excluded patients as candidates for intraocular implants. Follow-up of all patients was at least six months. Preoperative and postoperative uncorrected and best corrected visual acuity and endothelial cell counts, as well as power predictability and complications rates, were compared. Prelimi nary results indicated that postoperative visu al acuity, power predictability, and endotheli al cell counts were comparable for the two groups. There were, however, fewer sight threatening complications associated with epikeratophakia, and complications in these patients were successfully reversed by remov al and replacement of the lenticule. PROVIDING FUNCTIONAL VISION for the patient with monocular aphakia presents a particular challenge. Traditional aphakic spectacle correc tion is generally not acceptable as a result of induced anisometropia as great as 25% to 35%.1 Contact lens correction is satisfactory for many patients, but for those who cannot manipulate a contact lens because of tremor or arthritis, those for whom inconvenience and the expense of multiple lens replacements become a bur den, or those who are unable to tolerate a contact lens for other reasons, the aphakic eye is functionally blind. For these patients, and for those who require improved uncorrected vision
From the Department of Ophthalmology, University of Nebraska Medical Center, Omaha, Nebraska (Drs. Durrie and Dietze); and Oregon Health Sciences Univer sity, Portland, Oregon (Dr. Habrich). This study was presented in part at the American Society for Cataract and Refractive Surgery annual meeting, April 8, 1986, Los Angeles, California. Reprint requests to Daniel S. Durrie, M.D., 434 the Doctors Building, Omaha, NE 68131.
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and stereopsis for occupational or psychologi cal reasons, the remaining treatment options are surgical ones. Provided that preoperative examination shows normal visual potential, one of the many intraocular lenses available may be implanted as a secondary procedure. Published results indicate that postoperative uncorrected visual acuity generally is better than 20/40 in at least 80% of patients, and that approximately 90% of patients return to within one Snellen line of their preoperative best corrected acuity.26 Re ported complications after secondary lens im plantation occur at rates of 5% to 20% and include cystoid macular edema, intraocular hemorrhage, postoperative astigmatism, ischemic optic neuropathy, persistent uveitis, uveitis-glaucoma-hyphema syndrome, infec tious endophthalmitis, retinal detachment, and corneal decompensation.2,6"11 Some patients are not candidates for secon dary lens implantation because of chronic iritis, disorganized anterior chambers, or endothelial cell counts of less than 1,000 cells/mm2. Addi tionally, patients younger than 40 years of age would be at undetermined risk as a result of early endothelial cell loss and the prolonged presence of an intraocular foreign body. As an alternative, epikeratophakia is an extraocular procedure that evolved from the work of Jose Barraquer, M.D.,12 and was originally devel oped for the correction of monocular aphakia. It requires the suturing of a plus-powered donor lenticule to the patient's deepithelialized corneal surface. The lyophilized lenticules con tain no viable keratocytes, but are rapidly cov ered by host epithelium and gradually repopulated by host keratocytes.113"20 The accuracy of this procedure for aphakia is reported to be within 1 diopter of predicted correction, the average undercorrection is 0.43 diopters, and mean visual acuity improves over the first year, largely as a result of gradual resolution of surface irregularity.15'18,20 Complications report ed after epikeratophakia include undercorrec-
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tion and overcorrection, astigmatism, interface opacity, infection, glare, vascularization, and chronic epitheliopathy.16,20"22 In this study we examined and compared the results of 30 consecutive secondary lens im plantations and 30 consecutive epikerato phakia procedures to correct aphakia, all per formed by one surgeon. Patients were not ran domized, as it was thought that they formed two distinct groups clinically. Results are re ported in terms of preoperative and postopera tive best corrected and uncorrected visual acu ity, power predictability (spherical equivalent), and endothelial cell counts. To our knowledge, no similar comparison of clinical results or prospective, randomized trial comparing these procedures has been reported.
Subjects and Methods Only aphakic adults who were unable to tolerate contact lenses were included in this series. Criteria for secondary intraocular lens implantation (in addition to aphakia) included age greater than 40 years and an endothelial cell count greater than 1,000 cells/mm 2 . Those who were candidates for secondary intraocular lens implantation according to the above crite ria underwent that procedure. An additional two patients who did not meet those criteria received implants: one was a 32-year-old who had a shortened life expectancy because of chronic renal failure, and the other had a low endothelial cell count and had received a sec ondary implant before epikeratophakia was available. Chronic iritis, disorganized anterior chamber, endothelial cell counts less than 1,000/mm2, and age less than 40 years were thus exclusionary criteria for intraocular interven tion. These patients were then considered for epikeratophakia. Patients who were poor can didates for epikeratophakia were those with corneal scarring in the visual axis or with se vere external disease, particularly uncontrolled blepharitis, keratitis sicca, and lagophthalmos, all of which would decrease the likelihood of a successful graft. Patients in the intraocular lens group ranged in age from 32 to 91 years (median = 65 years). A mean of 49 months (range, five months to 12 years) had elapsed since cataract extraction. Patients in the epikeratophakia group ranged in age from 20 to 83 years (median = 59 years).
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A mean of 92 months (range, three months to 32 years) had passed since the primary proce dure. Each patient had a full preoperative ex amination, including slit-lamp biomicroscopy, objective and subjective manifest refraction, and dilated ophthalmoscopic examination. Vis ual acuity was measured without correction and with best correction (spectacle or contact lens). A-scan axial length measurements and keratometric readings were used in calculating the optical correction desired. Additionally, intraocular pressure, central corneal thickness, and endothelial cell counts were recorded. Corneoscopic photographs were taken of most patients. All procedures were performed by one of us (D.S.D.). Local anesthesia was used in most cases. All consecutive cases are included in this study. In the intraocular lens group a standard 7-mm limbal incision was made. The pupils had been previously constricted with pilocarpine 1%. Anterior vitrectomy was performed if indi cated, and sodium hyaluronate was used in the anterior chamber in all cases. A peripheral iridectomy was made if none was present or if there was some question as to its patency. The types of anterior chamber lenses used are listed in the Table. Incisions were closed with 10-0 nylon sutures. Postoperatively, patients re ceived topical antibiotic and corticosteroid medications. In the epikeratophakia group epikerato phakia was performed according to the Proto col for the Clinical Study of the Kerato-Lens in Epikeratophakia for the Treatment of Aphakia, issued by Allergan Medical Optics, August 1985. Lyophilized lenticules were rehydrated for 20 minutes in balanced salt solution with 0.1 ml of gentamicin added (final concentration= 100 |xg/ml). The optical center was marked on
TABLE ANTERIOR CHAMBER LENSES USED IN THE INTRAOCULAR LENS GROUP TYPE
Stableflex Optiflex Simco Quadraflex Pannu S-Flex
MANUFACTURER
Optical Radiation Corp. Cilco Cilco Cilco Cilco Cilco
NO. IMPL/
21 4 2 1 1 1
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the cornea, and a minimal amount of absolute alcohol was applied. The corneal epithelium was removed using a combination of mechani cal and chemical debridement. Care was taken not to damage Bowman's layer. A peripheral cuff of epithelium and a 3-mm area containing the centering mark were left in place. Copious irrigation was employed to remove debris and residual cells. A 7.0-mm trephine was centered over the optical axis and a circular keratotomy was created to a depth of 0.3 mm. A Vannas scissors was used to remove a wedge-shaped section of corneal stroma from the inner aspect of the trephine cut, thus creating an annular keratectomy 0.3 mm deep and 0.5 mm wide. The outer aspect was undermined 1.0 mm circumferentially. The remaining epithelium was removed and the cornea irrigated. The precut lenticule (8.5 mm in diameter) was sutured in place with 16 interrupted 10-0 nylon sutures. The edge of the lenticule was tucked into the potential space created, after eight sutures were placed. Care was taken not to pull the sutures too tightly, thus preserving the plus power of the lenticule. A keratometer was used intraoperatively to ensure a more nearly spher ical result. All patients received gentamicin eyedrops postoperatively for two to eight weeks until the sutures were removed. Topical corticosteroids were used only in cases of sig nificant inflammation.
Results All patients were followed up for at least six months postoperatively. Preoperative best cor rected visual acuity was measured using con tact lenses and overrefraction or aphakic refrac tion. Postoperatively, uncorrected visual acuity was measured using standard Snellen projec tion charts. Patients were then refracted to obtain the best corrected visual acuity. In the group that received intraocular lenses, nine patients (30%) had uncorrected visual acu ity postoperatively of 20/40 or better. When converted to decimal values for purposes of calculation, mean uncorrected visual acuity was 20/50, with a range from 20/20 to counting fingers (Fig. 1). Among the patients receiving epikeratophakia, seven (23%) had uncorrected visual acuity of 20/40 or better, with a mean of 20/60 (range, 20/25 to 20/200) (Fig. 2). A moder ate amount of scatter is seen in the intraocular lens group because of surgically induced astig matism and other complications that are dis cussed below. In Figures 3 and 4, preoperative best correct ed visual acuity is plotted against postoperative best corrected visual acuity. Twenty-two (73%) of the patients receiving intraocular lenses had postoperative best corrected visual acuity equal to or better than their preoperative visual acu-
• •
20/20 20/40-
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Fig. 1 (Durrie, Habrich, and Dietze). Postoperative uncorrected visual acuity for patients receiving intraocu lar lens implants. Follow-up greater than six months.
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• • Fig. 2 (Durrie, Habrich, and Dietze). Postoperative uncorrected visual acuity in the epikeratophakia group. Follow-up greater than six months.
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generation changes. Another patient's visual acuity decreased from 20/50 to 20/100 because of irregular astigmatism. Despite decreases in best corrected visual acuity in some patients as a result of the epikeratophakia procedure, many patients were so contact lens intolerant preoperatively that they were functionally blind before epikeratophakia. In Figures 5 and 6, power desired is com pared with power obtained in diopters of cor rection. Patients falling below the line of identi ty are undercorrected, and those above the line are overcorrected. In the intraocular lens
ity (points to the left of the line of identity). Visual acuity ranged from 20/20 to counting fingers, with 21 patients (70%) having a visual acuity of 20/40 or better. In the epikeratophakia group, 16 (53%) patients had postoperative best corrected visual acuity equal to or better than preoperative values. Twenty-one (70%) of this group had a visual acuity of 20/40 or better (range, 20/15 to 20/80). Two patients in this group had moderately to markedly decreased postoperative visual acuity. One patient's visu al acuity decreased from 20/30 to 20/80 as a result of documented, age-related macular de
BETTER Preoperative mean
20/30
Postoperative mea n 2 0 / 3 0 * Ul
> gj 20/60 Q.
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o
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PREOPERATIVE
Fig. 3 (Durrie, Habrich, and Dietze). Best corrected visual acuity preoperatively is plotted against best cor rected postoperative visual acuity in the intraocular lens group. Points to the left of the line of identity represent postoperative visual acuities better than preoperative, and those to the right, worse than preoperative visual acuity.
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Fig. 4 (Durrie, Habrich, and Dietze). Best corrected visual acuity preoperatively vs best corrected visual acu ity postoperatively in the epikeratophakia group.
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group, patients are clustered tightly near the line of identity except for two patients. The majority of patients are slightly overcorrected. This may be the result of either the intraocular lens calculation formula used or the surgical technique. The mean postoperative spherical
equivalent was —0.82 diopters (range, —3.25 to +4.00 diopters). In the epikeratophakia group there is more scattering of the actual power obtained with a tendency toward undercorrection in the lower power lenticules, and overcorrection in the higher power lenticules. The
OVERCORRECTED
Fig. 5 (Durrie, Habrich, and Dietze). Power predicta bility for patients receiving intraocular lens implants. Points above the line of iden tity represent overcorrections, below the line, undercorrections.
h UNDERCORRECTED
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Fig. 6 (Durrie, Habrich, and Dietze). Power predicta bility for patients with epi keratophakia lenticules.
POWER DESIRED (in diopters)
mean spherical equivalent was +0.58 diopters (range, -3.87 to +3.25 diopters). Among the intraocular lens group, 26 (87%) had a final refraction (spherical equivalent) within two di opters of piano. Of the epikeratophakia pa tients, 21 (70%) fell within these limits. Preoperatively, the mean endothelial cell count for the intraocular lens group was 1,700 cells/mm 2 (range, 600 to 2,700 cells/mm 2 ). Four to six months postoperatively the mean was 1,600 cells/mm 2 (range, 100 to 2,800 cells/mm 2 ). For the epikeratophakia group, the preoperative mean was 1,800 cells/mm 2 (range, 1,000 to 3,500 cells/mm 2 ), and postoperatively the mean was 1,600 cells/mm 2 (range, 700 to 2,400 cells/mm 2 ). Factors of polymorphism and polymegethism were not addressed in this study. Of the 30 patients who received intraocular lenses, five (17%) experienced complications, four of whom (13%) required intraocular surgi cal intervention. Two patients developed uveitis-glaucoma-hyphema syndrome, necessi tating removal of the lens. One of these pa tients, who developed cystoid macular edema, had a final best corrected visual acuity of count ing fingers (Fig. 3). One patient had a pupillary
block and eventually required vitrectomy. She now is doing well, with a best corrected visual acuity of 20/20. A fourth patient required pene trating keratoplasty for pseudophakic bullous keratopathy and achieved a best corrected visu al acuity of 20/100. The fifth patient developed glaucoma as a result of anterior synechiae, which is currently medically controlled. The complication rate among the epikerato phakia group was 13% (four patients): one case each of interface infiltrate, graft edge melt, delayed epithelialization, and irregular astig matism. All of these patients underwent re moval and replacement of the lenticule with a satisfactory visual result.
Discussion Although fewer of the patients receiving epikeratophakia grafts achieved uncorrected visual acuity in the 20/40 or better range, their visual acuity values were clustered more con sistently around the mean acuity (20/60), and demonstrated less scatter than the group re-
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ceiving intraocular l e n s e s . A s i d e from the five p a t i e n t s in t h e i n t r a o c u l a r lens g r o u p w i t h t r u e c o m p l i c a t i o n s , variation in the i n t r a o c u l a r lens g r o u p s e e m e d to be related to surgically in d u c e d a s t i g m a t i s m , yielding p o o r e r unconnect ed visual acuity for s o m e of t h e s e p a t i e n t s . In all, 70% of t h e p a t i e n t s in b o t h g r o u p s a c h i e v e d best corrected visual acuity of 20/40 or b e t t e r . In a s s e s s i n g p o w e r predictability, 26 p a t i e n t s (87%) in the intraocular lens g r o u p a n d 21 p a t i e n t s (70%) in t h e e p i k e r a t o p h a k i a g r o u p h a d a final spherical e q u i v a l e n t refraction w i t h in two d i o p t e r s of p i a n o . A c o m p a r i s o n of Figures 5 a n d 6 indicates g r e a t e r accuracy in p r e d i c t i n g p o w e r in the intraocular lens g r o u p . C o m p l i c a t i o n rates w e r e similar in t h e two g r o u p s . The c o m p l i c a t i o n s that o c c u r r e d in t h e e p i k e r a t o p h a k i a g r o u p w e r e easily r e v e r s e d , a n d n o n e w a s sight t h r e a t e n i n g . While p a t i e n t s in n e i t h e r of o u r g r o u p s e x p e r i e n c e d major e n d o t h e l i a l cell loss, recent reports 2 2 2 3 s u g g e s t that cell size a n d p o l y m o r p h i s m m a y b e useful long-term i n d i c a t o r s of functional e n d o t h e l i a l r e s e r v e . T h e s e factors w e r e not u s e d in the p r e s e n t s t u d y , b u t m a y be helpful in the fu ture. Statistical a n a l y s i s of o u r d a t a is limited by its r e t r o s p e c t i v e n a t u r e . In the f u t u r e , m o r e objec tive information w o u l d b e o b t a i n e d in a p r o spective, r a n d o m i z e d clinical trial. C o n t i n u e d follow-up, particularly of p a t i e n t s receiving t h e e p i k e r a t o p h a k i a p r o c e d u r e , is n e e d e d . A d d i tional modifications in surgical t e c h n i q u e a n d d e v e l o p m e n t s in i n t r a o c u l a r lens a n d epiker a t o p h a k i a d e s i g n will c o n t i n u e to i m p r o v e sur gical results. O u r results indicate that b o t h p r o c e d u r e s can p r o v i d e useful vision to eyes t h a t p r e v i o u s l y w e r e functionally b l i n d . In selecting a p r o c e d u r e , objective m e a s u r e m e n t s of visual acuity a n d refraction m u s t be c o m b i n e d w i t h the pa tient's functional vision for daily activities. Vis ual recovery in s e c o n d a r y lens i m p l a n t a t i o n is usually swift, b u t the p r o c e d u r e m a y p o s e a possible risk for a particular p a t i e n t . As w a s found in p r e v i o u s studies 1 4 1 6 1 8 visual r e c o v e r y o c c u r r e d g r a d u a l l y over t h e first year after e p i k e r a t o p h a k i a . This m a y b e a n i m p o r t a n t c o n s i d e r a t i o n for s o m e p a t i e n t s w h o r e q u i r e early functional vision. P r e o p e r a t i v e a s s e s s m e n t of risk related to rate a n d severity of complications m u s t be m a d e in each i n d i v i d u a l case. The most i m p o r t a n t c o n s i d e r a t i o n for the s u r g e o n is in relating t h e surgical o p t i o n s avail able to the i n d i v i d u a l p a t i e n t , a n d p r o c e e d i n g appropriately.
It is not o u r i n t e n t to s u g g e s t that e p i k e r a t o p h a k i a replace t h e i m p l a n t a t i o n of intraocular lenses for correction of a p h a k i a . We believe, h o w e v e r , that e p i k e r a t o p h a k i a is a safe a n d effective a l t e r n a t i v e . For t h o s e eyes t h a t r e q u i r e correction b u t h a v e c o n t r a i n d i c a t i o n s to intra ocular i n t e r v e n t i o n , it is the p r o c e d u r e of choice.
References 1. Kaufman, H. E.: The correction of aphakia. Am. J. Ophthalmol. 89:1, 1980. 2. Kraff, M. C , Sanders, D. R., Lieberman, H. L., and Kraff, ].: Secondary intraocular lens implanta tion. Ophthalmology 9:324, 1983. 3. Kratz, R. P., Mazzocco, T. R., Davidson, B., and Colvard, D. M.: The Shearing intraocular lens. A report of 1000 cases. Am. Intraocul. Implant Soc. J. 7:55, 1981. 4. Stanley, J. A.: Secondary implantation of intra ocular lenses. Trans. Pac. Coast Oto-Ophthalmol. Soc. 66:55, 1985. 5. Stark, W. J., Maumenee, A. E., Dangel, M. E., Martin, N. F., and Hirst, L. W.: Intraocular lenses. Experience at the Wilmer Institute. Ophthalmology 89:104, 1982. 6. Apple, D. J., Mamalis, N., Loftfield, K., Googe, J. M., Novak, L. C , Kavak-van Norman, D., Brady, S. E., and Olson, R. J.: Complications of intraocular lenses. A historical and histopathological review. Surv. Ophthalmol. 29:1, 1984. 7. Mazzocco, T. R., Kratz, R. P., Davidson, B., and Colvard, D. M.: Secondary lens implantation. Am. Intraocul. Implant Soc. J. 7:40, 1981. 8. Shammas, H. J. F., and Milkie, C. F.: Cystoid macular edema following secondary lens implanta tion. Am. Intraocul. Implant Soc. J. 4:180, 1978. 9. Shammas, H. J. F., and Milkie, C. F.: Second ary lens implantation in aphakia. Visual results and complications. Am. Intraocul. Implant Soc. J. 4:180, 1978. 10. Spedick, M. J., and Tomsak, R. L.: Ischemic optic neuropathy following secondary intraocular lens implantation. J. Clin. Neuro-ophthalmol. 4:255, 1984. 11. Swinger, C. A.: Comparison of results ob tained with epikeratophakia, hypermetropic keratomileusis, intraocular lens implantation, and extended-wear contact lenses. Int. Ophthalmol. Clin. 23:3, 1983. 12. Barraquer, J. I. (ed.): Refractive Keratoplasty, vol. 1. Bogota, Columbia, Instituto Barraquer de America, 1970. 13. Binder, P. S., Baumgartner, S. D., and Fogle, J. A.: Histopathology of a case of epikeratophakia (aphakic epikeratoplasty). Arch. Ophthalmol. 103:1347, 1985.
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14. Kaufman, H. E., and McDonald, M. B.: Re fractive surgery for aphakia and myopia. Trans. Ophthalmol Soc. U.K. 104:43, 1985. 15. McDonald, M. B., Koenig, S. B., Safir, A., Friedlander, M. H., Kaufman, H. E., and Granet, N.: Epikeratophakia. The surgical correction of aphakia-update. 1982. Ophthalmology 90:672, 1983. 16. Werblin, T. P.: Epikeratophakia. Techniques, complications and clinical results. Int. Ophthalmol. Clin. 23:45, 1983. 17. Werblin, T. P., Kaufman, H. E., Friedlander, M. H., and Granet, N.: Epikeratophakia. The surgi cal correction of aphakia. III. Preliminary results of a prospective clinical trial. Arch. Ophthalmol. 99:1957, 1981. 18. Werblin, T. P., Kaufman, H. E., Friedlander, M. H., McDonald, M. B., and Sehon, K. L.: Epiker atophakia. The surgical correction of aphakiaupdate. 1981. Ophthalmology 89:916, 1982.
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19. Werblin, T. P., Kaufman, H. E., Friedlander, M. H., Sehon, K. L., McDonald, M. B., and Granet, N. S.: A prospective study of the use of hyperopic epikeratophakia grafts for the correction of aphakia in adults. Ophthalmology 88:1137, 1981. 20. Binder, P. S.: Optical problems following re fractive surgery. Ophthalmology 93:39, 1986. 21. Matsuda, M., Suda, T., and Manabe, R.: Serial alterations in endothelial cell shape and pattern after intraocular surgery. Am. J. Ophthalmol. 98:313, 1984. 22. Rao, G. N., Aquavella, J. V., Goldberg, S. H., and Berk, S. L.: Pseudophakic bullous keratopathy. Relationship to preoperative corneal endothelial sta tus. Ophthalmology 91:1135, 1984. 23. Rao, G. N., Shaw, E. L., Arthur, E. ] . , and Aquavella, J. V.: Endothelial cell morphology and corneal deturgescence. Ann. Ophthalmol. 11:885, 1979.
From the Department of Ophthalmology, University of Nebraska Medical Center, Omaha, Nebraska (Drs. Durrie and Dietze); and Oregon Health Sciences Univer sity, Portland, Oregon (Dr. Habrich). This study was presented in part at the American Society for Cataract and Refractive Surgery annual meeting, April 8, 1986, Los Angeles, California. Reprint requests to Daniel S. Durrie, M.D., 434 the Doctors Building, Omaha, NE 68131.
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and stereopsis for occupational or psychologi cal reasons, the remaining treatment options are surgical ones. Provided that preoperative examination shows normal visual potential, one of the many intraocular lenses available may be implanted as a secondary procedure. Published results indicate that postoperative uncorrected visual acuity generally is better than 20/40 in at least 80% of patients, and that approximately 90% of patients return to within one Snellen line of their preoperative best corrected acuity.26 Re ported complications after secondary lens im plantation occur at rates of 5% to 20% and include cystoid macular edema, intraocular hemorrhage, postoperative astigmatism, ischemic optic neuropathy, persistent uveitis, uveitis-glaucoma-hyphema syndrome, infec tious endophthalmitis, retinal detachment, and corneal decompensation.2,6"11 Some patients are not candidates for secon dary lens implantation because of chronic iritis, disorganized anterior chambers, or endothelial cell counts of less than 1,000 cells/mm2. Addi tionally, patients younger than 40 years of age would be at undetermined risk as a result of early endothelial cell loss and the prolonged presence of an intraocular foreign body. As an alternative, epikeratophakia is an extraocular procedure that evolved from the work of Jose Barraquer, M.D.,12 and was originally devel oped for the correction of monocular aphakia. It requires the suturing of a plus-powered donor lenticule to the patient's deepithelialized corneal surface. The lyophilized lenticules con tain no viable keratocytes, but are rapidly cov ered by host epithelium and gradually repopulated by host keratocytes.113"20 The accuracy of this procedure for aphakia is reported to be within 1 diopter of predicted correction, the average undercorrection is 0.43 diopters, and mean visual acuity improves over the first year, largely as a result of gradual resolution of surface irregularity.15'18,20 Complications report ed after epikeratophakia include undercorrec-
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Intraocular Lens Implantation vs Epikeratophakia
tion and overcorrection, astigmatism, interface opacity, infection, glare, vascularization, and chronic epitheliopathy.16,20"22 In this study we examined and compared the results of 30 consecutive secondary lens im plantations and 30 consecutive epikerato phakia procedures to correct aphakia, all per formed by one surgeon. Patients were not ran domized, as it was thought that they formed two distinct groups clinically. Results are re ported in terms of preoperative and postopera tive best corrected and uncorrected visual acu ity, power predictability (spherical equivalent), and endothelial cell counts. To our knowledge, no similar comparison of clinical results or prospective, randomized trial comparing these procedures has been reported.
Subjects and Methods Only aphakic adults who were unable to tolerate contact lenses were included in this series. Criteria for secondary intraocular lens implantation (in addition to aphakia) included age greater than 40 years and an endothelial cell count greater than 1,000 cells/mm 2 . Those who were candidates for secondary intraocular lens implantation according to the above crite ria underwent that procedure. An additional two patients who did not meet those criteria received implants: one was a 32-year-old who had a shortened life expectancy because of chronic renal failure, and the other had a low endothelial cell count and had received a sec ondary implant before epikeratophakia was available. Chronic iritis, disorganized anterior chamber, endothelial cell counts less than 1,000/mm2, and age less than 40 years were thus exclusionary criteria for intraocular interven tion. These patients were then considered for epikeratophakia. Patients who were poor can didates for epikeratophakia were those with corneal scarring in the visual axis or with se vere external disease, particularly uncontrolled blepharitis, keratitis sicca, and lagophthalmos, all of which would decrease the likelihood of a successful graft. Patients in the intraocular lens group ranged in age from 32 to 91 years (median = 65 years). A mean of 49 months (range, five months to 12 years) had elapsed since cataract extraction. Patients in the epikeratophakia group ranged in age from 20 to 83 years (median = 59 years).
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A mean of 92 months (range, three months to 32 years) had passed since the primary proce dure. Each patient had a full preoperative ex amination, including slit-lamp biomicroscopy, objective and subjective manifest refraction, and dilated ophthalmoscopic examination. Vis ual acuity was measured without correction and with best correction (spectacle or contact lens). A-scan axial length measurements and keratometric readings were used in calculating the optical correction desired. Additionally, intraocular pressure, central corneal thickness, and endothelial cell counts were recorded. Corneoscopic photographs were taken of most patients. All procedures were performed by one of us (D.S.D.). Local anesthesia was used in most cases. All consecutive cases are included in this study. In the intraocular lens group a standard 7-mm limbal incision was made. The pupils had been previously constricted with pilocarpine 1%. Anterior vitrectomy was performed if indi cated, and sodium hyaluronate was used in the anterior chamber in all cases. A peripheral iridectomy was made if none was present or if there was some question as to its patency. The types of anterior chamber lenses used are listed in the Table. Incisions were closed with 10-0 nylon sutures. Postoperatively, patients re ceived topical antibiotic and corticosteroid medications. In the epikeratophakia group epikerato phakia was performed according to the Proto col for the Clinical Study of the Kerato-Lens in Epikeratophakia for the Treatment of Aphakia, issued by Allergan Medical Optics, August 1985. Lyophilized lenticules were rehydrated for 20 minutes in balanced salt solution with 0.1 ml of gentamicin added (final concentration= 100 |xg/ml). The optical center was marked on
TABLE ANTERIOR CHAMBER LENSES USED IN THE INTRAOCULAR LENS GROUP TYPE
Stableflex Optiflex Simco Quadraflex Pannu S-Flex
MANUFACTURER
Optical Radiation Corp. Cilco Cilco Cilco Cilco Cilco
NO. IMPL/
21 4 2 1 1 1
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the cornea, and a minimal amount of absolute alcohol was applied. The corneal epithelium was removed using a combination of mechani cal and chemical debridement. Care was taken not to damage Bowman's layer. A peripheral cuff of epithelium and a 3-mm area containing the centering mark were left in place. Copious irrigation was employed to remove debris and residual cells. A 7.0-mm trephine was centered over the optical axis and a circular keratotomy was created to a depth of 0.3 mm. A Vannas scissors was used to remove a wedge-shaped section of corneal stroma from the inner aspect of the trephine cut, thus creating an annular keratectomy 0.3 mm deep and 0.5 mm wide. The outer aspect was undermined 1.0 mm circumferentially. The remaining epithelium was removed and the cornea irrigated. The precut lenticule (8.5 mm in diameter) was sutured in place with 16 interrupted 10-0 nylon sutures. The edge of the lenticule was tucked into the potential space created, after eight sutures were placed. Care was taken not to pull the sutures too tightly, thus preserving the plus power of the lenticule. A keratometer was used intraoperatively to ensure a more nearly spher ical result. All patients received gentamicin eyedrops postoperatively for two to eight weeks until the sutures were removed. Topical corticosteroids were used only in cases of sig nificant inflammation.
Results All patients were followed up for at least six months postoperatively. Preoperative best cor rected visual acuity was measured using con tact lenses and overrefraction or aphakic refrac tion. Postoperatively, uncorrected visual acuity was measured using standard Snellen projec tion charts. Patients were then refracted to obtain the best corrected visual acuity. In the group that received intraocular lenses, nine patients (30%) had uncorrected visual acu ity postoperatively of 20/40 or better. When converted to decimal values for purposes of calculation, mean uncorrected visual acuity was 20/50, with a range from 20/20 to counting fingers (Fig. 1). Among the patients receiving epikeratophakia, seven (23%) had uncorrected visual acuity of 20/40 or better, with a mean of 20/60 (range, 20/25 to 20/200) (Fig. 2). A moder ate amount of scatter is seen in the intraocular lens group because of surgically induced astig matism and other complications that are dis cussed below. In Figures 3 and 4, preoperative best correct ed visual acuity is plotted against postoperative best corrected visual acuity. Twenty-two (73%) of the patients receiving intraocular lenses had postoperative best corrected visual acuity equal to or better than their preoperative visual acu-
• •
20/20 20/40-
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Fig. 1 (Durrie, Habrich, and Dietze). Postoperative uncorrected visual acuity for patients receiving intraocu lar lens implants. Follow-up greater than six months.
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• • Fig. 2 (Durrie, Habrich, and Dietze). Postoperative uncorrected visual acuity in the epikeratophakia group. Follow-up greater than six months.
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generation changes. Another patient's visual acuity decreased from 20/50 to 20/100 because of irregular astigmatism. Despite decreases in best corrected visual acuity in some patients as a result of the epikeratophakia procedure, many patients were so contact lens intolerant preoperatively that they were functionally blind before epikeratophakia. In Figures 5 and 6, power desired is com pared with power obtained in diopters of cor rection. Patients falling below the line of identi ty are undercorrected, and those above the line are overcorrected. In the intraocular lens
ity (points to the left of the line of identity). Visual acuity ranged from 20/20 to counting fingers, with 21 patients (70%) having a visual acuity of 20/40 or better. In the epikeratophakia group, 16 (53%) patients had postoperative best corrected visual acuity equal to or better than preoperative values. Twenty-one (70%) of this group had a visual acuity of 20/40 or better (range, 20/15 to 20/80). Two patients in this group had moderately to markedly decreased postoperative visual acuity. One patient's visu al acuity decreased from 20/30 to 20/80 as a result of documented, age-related macular de
BETTER Preoperative mean
20/30
Postoperative mea n 2 0 / 3 0 * Ul
> gj 20/60 Q.
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o
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20/80
fr(CF)
PREOPERATIVE
Fig. 3 (Durrie, Habrich, and Dietze). Best corrected visual acuity preoperatively is plotted against best cor rected postoperative visual acuity in the intraocular lens group. Points to the left of the line of identity represent postoperative visual acuities better than preoperative, and those to the right, worse than preoperative visual acuity.
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BETTER
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20/40
Fig. 4 (Durrie, Habrich, and Dietze). Best corrected visual acuity preoperatively vs best corrected visual acu ity postoperatively in the epikeratophakia group.
20/20
PREOPERATIVE
group, patients are clustered tightly near the line of identity except for two patients. The majority of patients are slightly overcorrected. This may be the result of either the intraocular lens calculation formula used or the surgical technique. The mean postoperative spherical
equivalent was —0.82 diopters (range, —3.25 to +4.00 diopters). In the epikeratophakia group there is more scattering of the actual power obtained with a tendency toward undercorrection in the lower power lenticules, and overcorrection in the higher power lenticules. The
OVERCORRECTED
Fig. 5 (Durrie, Habrich, and Dietze). Power predicta bility for patients receiving intraocular lens implants. Points above the line of iden tity represent overcorrections, below the line, undercorrections.
h UNDERCORRECTED
-410
- 1 11
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POWER DESIRED (in diopters)
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Intraocular Lens Implantation vs Epikeratophakia
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Fig. 6 (Durrie, Habrich, and Dietze). Power predicta bility for patients with epi keratophakia lenticules.
POWER DESIRED (in diopters)
mean spherical equivalent was +0.58 diopters (range, -3.87 to +3.25 diopters). Among the intraocular lens group, 26 (87%) had a final refraction (spherical equivalent) within two di opters of piano. Of the epikeratophakia pa tients, 21 (70%) fell within these limits. Preoperatively, the mean endothelial cell count for the intraocular lens group was 1,700 cells/mm 2 (range, 600 to 2,700 cells/mm 2 ). Four to six months postoperatively the mean was 1,600 cells/mm 2 (range, 100 to 2,800 cells/mm 2 ). For the epikeratophakia group, the preoperative mean was 1,800 cells/mm 2 (range, 1,000 to 3,500 cells/mm 2 ), and postoperatively the mean was 1,600 cells/mm 2 (range, 700 to 2,400 cells/mm 2 ). Factors of polymorphism and polymegethism were not addressed in this study. Of the 30 patients who received intraocular lenses, five (17%) experienced complications, four of whom (13%) required intraocular surgi cal intervention. Two patients developed uveitis-glaucoma-hyphema syndrome, necessi tating removal of the lens. One of these pa tients, who developed cystoid macular edema, had a final best corrected visual acuity of count ing fingers (Fig. 3). One patient had a pupillary
block and eventually required vitrectomy. She now is doing well, with a best corrected visual acuity of 20/20. A fourth patient required pene trating keratoplasty for pseudophakic bullous keratopathy and achieved a best corrected visu al acuity of 20/100. The fifth patient developed glaucoma as a result of anterior synechiae, which is currently medically controlled. The complication rate among the epikerato phakia group was 13% (four patients): one case each of interface infiltrate, graft edge melt, delayed epithelialization, and irregular astig matism. All of these patients underwent re moval and replacement of the lenticule with a satisfactory visual result.
Discussion Although fewer of the patients receiving epikeratophakia grafts achieved uncorrected visual acuity in the 20/40 or better range, their visual acuity values were clustered more con sistently around the mean acuity (20/60), and demonstrated less scatter than the group re-
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ceiving intraocular l e n s e s . A s i d e from the five p a t i e n t s in t h e i n t r a o c u l a r lens g r o u p w i t h t r u e c o m p l i c a t i o n s , variation in the i n t r a o c u l a r lens g r o u p s e e m e d to be related to surgically in d u c e d a s t i g m a t i s m , yielding p o o r e r unconnect ed visual acuity for s o m e of t h e s e p a t i e n t s . In all, 70% of t h e p a t i e n t s in b o t h g r o u p s a c h i e v e d best corrected visual acuity of 20/40 or b e t t e r . In a s s e s s i n g p o w e r predictability, 26 p a t i e n t s (87%) in the intraocular lens g r o u p a n d 21 p a t i e n t s (70%) in t h e e p i k e r a t o p h a k i a g r o u p h a d a final spherical e q u i v a l e n t refraction w i t h in two d i o p t e r s of p i a n o . A c o m p a r i s o n of Figures 5 a n d 6 indicates g r e a t e r accuracy in p r e d i c t i n g p o w e r in the intraocular lens g r o u p . C o m p l i c a t i o n rates w e r e similar in t h e two g r o u p s . The c o m p l i c a t i o n s that o c c u r r e d in t h e e p i k e r a t o p h a k i a g r o u p w e r e easily r e v e r s e d , a n d n o n e w a s sight t h r e a t e n i n g . While p a t i e n t s in n e i t h e r of o u r g r o u p s e x p e r i e n c e d major e n d o t h e l i a l cell loss, recent reports 2 2 2 3 s u g g e s t that cell size a n d p o l y m o r p h i s m m a y b e useful long-term i n d i c a t o r s of functional e n d o t h e l i a l r e s e r v e . T h e s e factors w e r e not u s e d in the p r e s e n t s t u d y , b u t m a y be helpful in the fu ture. Statistical a n a l y s i s of o u r d a t a is limited by its r e t r o s p e c t i v e n a t u r e . In the f u t u r e , m o r e objec tive information w o u l d b e o b t a i n e d in a p r o spective, r a n d o m i z e d clinical trial. C o n t i n u e d follow-up, particularly of p a t i e n t s receiving t h e e p i k e r a t o p h a k i a p r o c e d u r e , is n e e d e d . A d d i tional modifications in surgical t e c h n i q u e a n d d e v e l o p m e n t s in i n t r a o c u l a r lens a n d epiker a t o p h a k i a d e s i g n will c o n t i n u e to i m p r o v e sur gical results. O u r results indicate that b o t h p r o c e d u r e s can p r o v i d e useful vision to eyes t h a t p r e v i o u s l y w e r e functionally b l i n d . In selecting a p r o c e d u r e , objective m e a s u r e m e n t s of visual acuity a n d refraction m u s t be c o m b i n e d w i t h the pa tient's functional vision for daily activities. Vis ual recovery in s e c o n d a r y lens i m p l a n t a t i o n is usually swift, b u t the p r o c e d u r e m a y p o s e a possible risk for a particular p a t i e n t . As w a s found in p r e v i o u s studies 1 4 1 6 1 8 visual r e c o v e r y o c c u r r e d g r a d u a l l y over t h e first year after e p i k e r a t o p h a k i a . This m a y b e a n i m p o r t a n t c o n s i d e r a t i o n for s o m e p a t i e n t s w h o r e q u i r e early functional vision. P r e o p e r a t i v e a s s e s s m e n t of risk related to rate a n d severity of complications m u s t be m a d e in each i n d i v i d u a l case. The most i m p o r t a n t c o n s i d e r a t i o n for the s u r g e o n is in relating t h e surgical o p t i o n s avail able to the i n d i v i d u a l p a t i e n t , a n d p r o c e e d i n g appropriately.
It is not o u r i n t e n t to s u g g e s t that e p i k e r a t o p h a k i a replace t h e i m p l a n t a t i o n of intraocular lenses for correction of a p h a k i a . We believe, h o w e v e r , that e p i k e r a t o p h a k i a is a safe a n d effective a l t e r n a t i v e . For t h o s e eyes t h a t r e q u i r e correction b u t h a v e c o n t r a i n d i c a t i o n s to intra ocular i n t e r v e n t i o n , it is the p r o c e d u r e of choice.
References 1. Kaufman, H. E.: The correction of aphakia. Am. J. Ophthalmol. 89:1, 1980. 2. Kraff, M. C , Sanders, D. R., Lieberman, H. L., and Kraff, ].: Secondary intraocular lens implanta tion. Ophthalmology 9:324, 1983. 3. Kratz, R. P., Mazzocco, T. R., Davidson, B., and Colvard, D. M.: The Shearing intraocular lens. A report of 1000 cases. Am. Intraocul. Implant Soc. J. 7:55, 1981. 4. Stanley, J. A.: Secondary implantation of intra ocular lenses. Trans. Pac. Coast Oto-Ophthalmol. Soc. 66:55, 1985. 5. Stark, W. J., Maumenee, A. E., Dangel, M. E., Martin, N. F., and Hirst, L. W.: Intraocular lenses. Experience at the Wilmer Institute. Ophthalmology 89:104, 1982. 6. Apple, D. J., Mamalis, N., Loftfield, K., Googe, J. M., Novak, L. C , Kavak-van Norman, D., Brady, S. E., and Olson, R. J.: Complications of intraocular lenses. A historical and histopathological review. Surv. Ophthalmol. 29:1, 1984. 7. Mazzocco, T. R., Kratz, R. P., Davidson, B., and Colvard, D. M.: Secondary lens implantation. Am. Intraocul. Implant Soc. J. 7:40, 1981. 8. Shammas, H. J. F., and Milkie, C. F.: Cystoid macular edema following secondary lens implanta tion. Am. Intraocul. Implant Soc. J. 4:180, 1978. 9. Shammas, H. J. F., and Milkie, C. F.: Second ary lens implantation in aphakia. Visual results and complications. Am. Intraocul. Implant Soc. J. 4:180, 1978. 10. Spedick, M. J., and Tomsak, R. L.: Ischemic optic neuropathy following secondary intraocular lens implantation. J. Clin. Neuro-ophthalmol. 4:255, 1984. 11. Swinger, C. A.: Comparison of results ob tained with epikeratophakia, hypermetropic keratomileusis, intraocular lens implantation, and extended-wear contact lenses. Int. Ophthalmol. Clin. 23:3, 1983. 12. Barraquer, J. I. (ed.): Refractive Keratoplasty, vol. 1. Bogota, Columbia, Instituto Barraquer de America, 1970. 13. Binder, P. S., Baumgartner, S. D., and Fogle, J. A.: Histopathology of a case of epikeratophakia (aphakic epikeratoplasty). Arch. Ophthalmol. 103:1347, 1985.
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14. Kaufman, H. E., and McDonald, M. B.: Re fractive surgery for aphakia and myopia. Trans. Ophthalmol Soc. U.K. 104:43, 1985. 15. McDonald, M. B., Koenig, S. B., Safir, A., Friedlander, M. H., Kaufman, H. E., and Granet, N.: Epikeratophakia. The surgical correction of aphakia-update. 1982. Ophthalmology 90:672, 1983. 16. Werblin, T. P.: Epikeratophakia. Techniques, complications and clinical results. Int. Ophthalmol. Clin. 23:45, 1983. 17. Werblin, T. P., Kaufman, H. E., Friedlander, M. H., and Granet, N.: Epikeratophakia. The surgi cal correction of aphakia. III. Preliminary results of a prospective clinical trial. Arch. Ophthalmol. 99:1957, 1981. 18. Werblin, T. P., Kaufman, H. E., Friedlander, M. H., McDonald, M. B., and Sehon, K. L.: Epiker atophakia. The surgical correction of aphakiaupdate. 1981. Ophthalmology 89:916, 1982.
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19. Werblin, T. P., Kaufman, H. E., Friedlander, M. H., Sehon, K. L., McDonald, M. B., and Granet, N. S.: A prospective study of the use of hyperopic epikeratophakia grafts for the correction of aphakia in adults. Ophthalmology 88:1137, 1981. 20. Binder, P. S.: Optical problems following re fractive surgery. Ophthalmology 93:39, 1986. 21. Matsuda, M., Suda, T., and Manabe, R.: Serial alterations in endothelial cell shape and pattern after intraocular surgery. Am. J. Ophthalmol. 98:313, 1984. 22. Rao, G. N., Aquavella, J. V., Goldberg, S. H., and Berk, S. L.: Pseudophakic bullous keratopathy. Relationship to preoperative corneal endothelial sta tus. Ophthalmology 91:1135, 1984. 23. Rao, G. N., Shaw, E. L., Arthur, E. ] . , and Aquavella, J. V.: Endothelial cell morphology and corneal deturgescence. Ann. Ophthalmol. 11:885, 1979.