Risk factors for complications following pediatric epikeratoplasty Kenneth P. Cheng, M.D., David A. Hiles, M.D., Albert W. Biglan, M.D., Milton C. Pettapiece, M.D., Scott C. Behler, M.D., Maria B. Moore, C.S.T. Epikeratoplasty is an effective treatment for aphakic children who are intolerant of contact lenses, for high hyperopia or myopia, and for apha- kia with corneal lacerations. I - 21 In the Allergan Medical Optics Nationwide Study ofEpikeratopha- kia for Aphakia in Children, the success rate of epikeratoplasty, as measured by graft clarity, was 89%. This increased to 95% when eyes that were successfully regrafted were included. 15 In a similar study of older children (between 8 and 18 years of age) who had epikeratoplasty, the overall success rate was 100% with the first graft. 17 Refractive complications of epikeratoplasty that have been reported include undercorrection or overcorrection of refractive errors, induction of regular or irregular astigmatism, and late loss of graft refractive power. 1 ,15,22-33 Medical compli- cations reported after epikeratoplasty include per- sistent failure of the graft to epithelialize, interface opacity, graft infection, necrosis, haziness, and wound separation with graft dehiscence or displacement. 18,22-33 In this paper we review our experience with epi- keratoplasty in children and report the prevalence and types of complications we encountered. As a result of this review, we identified risk factors that have modified our guidelines for patient selection for epikeratoplasty. From the Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Presented at the American Association for Pediatric Ophthalmology and Strabismus Meeting, Kiawah, South Carolina, 1989. Supported in part by grants to the Fight for Sight Children's Eye Clinic of Children's Hospital of Pittsburgh, Pennsylvania, and by Fight for Sight, Inc., New York, New York. The authors have no proprietary interest in Allergan Medical Optics. Reprint requests to Albert W. Biglan, M.D., 3518 Fifth Avenue, Pittsburgh, Pennsylvania 15213. 270 J CATARACT REFRACT SURG-VOL 18, MAY 1992
Transcript
Risk factors for complications following pediatric epikeratoplasty
Kenneth P. Cheng, M.D., David A. Hiles, M.D., Albert W. Biglan, M.D., Milton C. Pettapiece, M.D., Scott C. Behler, M.D., Maria B. Moore, C.S.T.
Epikeratoplasty is an effective treatment for aphakic children who are intolerant of contact lenses, for high hyperopia or myopia, and for aphakia with corneal lacerations. I
-21 In the Allergan
Medical Optics Nationwide Study ofEpikeratophakia for Aphakia in Children, the success rate of epikeratoplasty, as measured by graft clarity, was 89%. This increased to 95% when eyes that were successfully regrafted were included. 15 In a similar study of older children (between 8 and 18 years of age) who had epikeratoplasty, the overall success rate was 100% with the first graft. 17
Refractive complications of epikeratoplasty that have been reported include undercorrection or
overcorrection of refractive errors, induction of regular or irregular astigmatism, and late loss of graft refractive power. 1 ,15,22-33 Medical complications reported after epikeratoplasty include persistent failure of the graft to epithelialize, interface opacity, graft infection, necrosis, haziness, and wound separation with graft dehiscence or displacement. 18,22-33
In this paper we review our experience with epikeratoplasty in children and report the prevalence and types of complications we encountered. As a result of this review, we identified risk factors that have modified our guidelines for patient selection for epikeratoplasty.
From the Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
Presented at the American Association for Pediatric Ophthalmology and Strabismus Meeting, Kiawah, South Carolina, 1989.
Supported in part by grants to the Fight for Sight Children's Eye Clinic of Children's Hospital of Pittsburgh, Pennsylvania, and by Fight for Sight, Inc., New York, New York.
The authors have no proprietary interest in Allergan Medical Optics.
Reprint requests to Albert W. Biglan, M.D., 3518 Fifth Avenue, Pittsburgh, Pennsylvania 15213.
270 J CATARACT REFRACT SURG-VOL 18, MAY 1992
SUBJECTS AND METHODS
We reviewed the clinical records of three of the authors (D.A.H., A.W.B., M.C.P.) who treated 88 consecutive patients (1l4 epikeratoplasty grafts) between February 1983 and December 1988. The procedure was offered to children with large refractive errors who could not tolerate a contact lens or spectacles. The protocol was approved by our Institutional Review Board, and appropriate informed consent was obtained for each child participating in the study. Epikeratoplasty procedures were performed for the correction of aphakia, traumatic aphakia in eyes with corneal scars, unilateral or bilateral high myopia, and phakic high hyperopia. All graft tissue was lyophilized material commercially prepared by Allergan Medical Optics. Operative techniques and postoperative management followed the updated recommendations of the Allergan Medical Optics Nationwide Study of Epikeratophakia for Aphakia in Children. Graft powers were calculated to achieve emmetropia. The graft power was determined using keratometry and axial length of the globe or from the dioptric power and posterior curvature of a contact lens placed on the eye.
Data obtained from patients' clinical records included preoperative diagnosis, patient's age at epikeratoplasty, . graft power, cycloplegic refractive error measured one year after the procedure, and any postoperative complications. Refractive errors were recorded in spherocylinder form and later converted to spherical equivalent values.
Early postoperative complications were defined as those occurring within the first month, intermediate complications as those occurring between one and six months, and late complications as those occurring after six months.
RESULTS
Sixty-eight of the 88 patients in this series had unilateral epikeratoplasty and 20 patients received bilateral grafts, a total of 108 treated eyes. Five eyes received repeat grafts and one eye was regrafted a second time, a total of 114 procedures.
Grafts were placed to correct aphakia (94 eyes: 64 unilateral and 15 bilateral grafts), myopia greater than 8.0 diopters (D) (12 eyes: 4 unilateral and 4 bilateral grafts) and phakic high hyperopia (two eyes of one patient). Patients were from one month to 19 years old (mean 3 years, 2 months) when they had epikeratoplasty; 24 procedures were performed on children less than one year. The epikeratophakia procedure was combined with cataract removal in ten eyes (10.6%) of ten
patients (mean age 5 years, 5 months; range 8 months to 18 years).
During the study period, II grafts (10%) were removed because of delayed epithelialization, failure to epithelialize, or infection (Table 1).
Fifty-eight of the 108 eyes receiving grafts had an uncomplicated postoperative course and did not develop a refractive or medical complication. One year after surgery, these eyes had refractive errors within +3.0 D spherical equivalent from emmetropia and either no astigmatism or astigmatism of less than 3.0 D.
Refractive Complications One year after the procedure, the degree of op
tical correction in 30 eyes (30%) that had received grafts was unacceptable because of refractive errors of more than 3.0 D spherical equivalent (20 eyes) or more than 3.0 D of astigmatism (ten eyes). Two of these eyes had more than 3.0 D of astigmatism preoperatively.
Two (8%) of the 24 eyes that had received an epigraft before the patient was one year of age had refractive errors of more than plus or minus 3.0 D spherical equivalent one year after they were grafted. The remaining 22 eyes grafted at less than one year of age achieved refractive errors within 3.0 D spherical equivalent of emmetropia and had less than 3.0 D of astigmatism an average of 4.26 months after surgery.
Of the ten eyes with combined cataract extraction/epikeratoplasty procedures, two eyes (20%) had more than 3.0 D of spherical equivalent refractive error arid one of these eyes had more than 3.0 D of astigmatism. The prevalence of unacceptable refractive errors was compared to the number of years the surgeon had been performing epikeratoplasty (Figure 1).
Medical Complications Twenty-two eyes (19%) developed medical com
plications: six eyes had one complication, five eyes had two complications, six eyes had three complications, two eyes had four complications, two eyes had five complications, and one eye had six complications (Table 2).
Medical complications occurred in 6 of 24 grafts (25%) placed on the eyes of children less than one year of age and in 16 of 90 grafts (18 %) placed on the eyes of children more than one year of age.
The grafts on three of the ten eyes (30%) that had the combined (one-stage) cataract extraction and epikeratoplasty procedure developed medical complications. These included vascularization from the cataract wound, a persistent epithelial defect and an epithelial inclusion cyst in one pa-
ROP = retinopathy of prematurity RD = retinal detachment
tient, graft vascularization and melting in another patient, and a persistent epithelial defect in the third patient.
The prevalence of medical complications was inversely related to the surgeon's experience with
80
60
Interval from Graft to Removal
(mos)
2
1
2.5
1
7
19
1
13
6
12
Interval from Removal
to Regraft (mos)
7
3.5
2
11
2
Comments
Second graft clear for 21 months
Second graft removed-necrosis, third graft clear
Second graft clear for 40 months
Not regrafted, mental retardation
IOL used in place of graft
Awaits second graft
Second graft clear for 12 months
Glaucomatous optic atrophy, not regrafted
R.D., glaucoma, not regrafted
Second graft clear with ghost vessels
epikeratoplasty (Figure 1). The complication rate for grafts placed by surgeons with less than two years' experience was higher than the rate of complications for grafts placed by surgeons with two years or more experience (chi-square, P = .02) .
• % without complications
'" ~ 40 W
'0 'J!.
• % with refractive error > 3 diopters spherical equivalent or astigmatism> 3 diopters
• % with medical complications
o~------------~----------~------------~ 1 year
40 Eyes
272
2 years
20 Eyes
3 years
27 Eyes
4 years
21 Eyes
Surgeon's Experience in Years
J CATARACT REFRACT SURG-VOL 18, MAY 1992
Fig. 1. (Cheng) Complications related to surgeon's experience with epikeratoplasty.
Table 2. Occurrence of each type of medical complication.
The relationship between the complications that occurred and the preoperative diagnosis is shown in Table 3. The time of onset of the medical complications is presented in Table 4.
DISCUSSION
Epikeratoplasty has been used to correct large refractive errors in patients who cannot tolerate contact lenses or spectacles or who are aphakic and poor candidates for intraocular lens implantation.3,14,18,19 This procedure is particularly appealing to the pediatric ophthalmologist since it provides continuous optical correction of large refractive errors, does not require intraocular surgery, may be performed on both eyes, and may be removed and replaced if necessary.
There are disadvantages to this procedure. Considerable surgical skill is needed to perform this operation and children must have general anesthe-
sia at least twice; once for placement of the graft and a second time for removal of the sutures holding the graft in place. Frequent follow-up examinations over the first several postoperative months are required, and several of these examinations may have to be performed under anesthesia. A disadvantage that may influence amblyopia treatment is the length of time required for the graft to clear (one to three months) and for keratometric and refractive parameters to stabilize (up to six months).6,10,1l,19 In a study using nonlyophilized tissue in children it was suggested that nonlyophilized tissue became clear quicker than lyophilized graft tissue. 34
If we use graft clarity at the time of data collection as the sole criterion for success, the success rate in our series (including four eyes that received a second and one eye that received a third graft) was 95%. These results are comparable to those of
J CATARACT REFRACT SURG-VOL 18, MAY 1992 273
Table 3. Complications following epikeratoplasty grouped by preoperative diagnosis.
Optical Compli-cations Medical Complications
Opticalj Inter- Graft Number Number Refractive Epi- face Vascu- Graft Graft Graft Graft of Eyes
Principal of Eyes Errors thelial Opac- lariza- Infec- Necro- Graft Dehis- Re- Regraf-Diagnosis Treated S.E. Cyl. Defect ity tion tion sis Opacity cence moved ted
Congenital 58 8 7 8 4 4 2 3 5 1 5 3 cataract
Microcornea- 22 5 1 4 1 2 2 3 1 3 2 PHPV
Trauma 13 3 2 1 1 1 2 1
Severe myopia 12 4 2 1 1 1 1
Phakic severe 2 hypermetropia
Aphakic ROP 1 1 1 1
Total 108 20 12 14 6 8 2 5 11 3 11 6
PHPV = persistent hyperplastic primary vitreous ROP = retinopathy of prematurity S.E. = spherical equivalent greater than 3.0 D, but less than 3.0 D astigmatism CyJ. = regular or irregular astigmatic refractive error greater than 3.0 D
other studies, including the Nationwide Study of Epikeratophakia for Aphakia in Children 1.5 and the studies of Lass et aI.,29 Kelly and coauthors,8 Uusitalo and Lehtosalo,20 and Binder and Zavala22
using lyophilized tissue, as well as the results achieved by Armesto et aI. 34 using nonlyophilized tissue. Assessing the success of this operation by graft clarity alone can be misleading. Only 54% of the eyes treated in this study had an uncomplicated postoperative course with a clear graft and a refractive error that was within ± 3.0 D of emmetropia with less than 3.0 D of astigmatism.
The focus of this study was to analyze complications and to identify risk factors that might improve patient selection and therefore improve the success rate of this procedure in children. Complications were divided into two categories: refractive complications and medical complications.
Refractive Complications One year after grafting, 70% of the eyes in this
study had refractive errors within 3.0 D of emmetropia and less than 3.0 D of astigmatism. Some of these eyes had medical complications that resolved or were treated successfully. In the Nationwide Studies of Epikeratophakia for Aphakia in Children1.5 and in Older Children,17 73% of the eyes were within 3.0 D spherical equivalent of emmetropia. Although our success in achieving a small refractive error appears slightly less than the success of the nationwide studies, this may be due
Table 4. Time of onset of medical complications after epikeratoplasty .
Complication (Number of Eyes)
Inter-Interval to face Graft Graft Graft Onset of Opac- Infec- Necro- Dehis-
Complication ity tion sis cence
Perioperative 1 1 1 (0-30 days)
Intermediate 1 4 3 (1-6 months)
Late 4 1 (After 6 months)
Total 6 2 5 3 Eyes/Complications
to our method of data analysis. We have reported spherical equivalent as well as spherocylinder refractive errors to reflect clinically significant refractive errors more accurately. Ten (9%) of the eyes in our study had more than 3.0 D of regular or irregular astigmatism one year post grafting; two of the eyes had high preoperative astigmatism.
Patient age at the time of epikeratoplasty is important. When patients were grafted before they were one year of age, the procedure resulted in an acceptable refractive error in 92% of our 24 patients an average of 4.26 months postoperatively.
274 J CATARACT REFRACT SURG-VOL 18, MAY 1992
These patients continued to have acceptable refractive results one year post grafting. Although we were relatively successful in achieving a satisfactory optical correction in this age group, we agree with Morgan and coauthors,1.13 Arffa and coauthors,l°·ll and Hiles18 that placing a graft on an eye of a child less than one year of age is not advisable because of unpredictable globe growth. We currently recommend cataract aspiration followed by use of a contact lens for our patients less than one year of age because few infants fail to tolerate contact lenses. If a contact lens is poorly tolerated, epikeratoplasty may be performed as a secondary procedure.
We performed ten combined cataract aspiration and epikeratoplasty procedures. A combined procedure reduces the number of times the child must have general anesthesia; however, it is accompanied by the disadvantage of a softening of the globe permitting changes in the geometric configuration of the graft bed which makes placement of the corneal graft sutures more difficult. This increases the risk of irregular astigmatism. 21 The optical correction achieved with our combined procedures was comparable to that achieved with secondary epikeratoplasty; however, because of the disadvantages, we now avoid combined procedures when possible.
We examined our data to determine if a surgeon's experience with the epikeratoplasty procedure made a difference in achieving a satisfactory postoperative refractive error (Figure 1). We found no significant difference in refractive error following surgery performed by a surgeon with two years or more experience with the procedure.
Six grafts provided inadequate correction of high myopia, for a success rate of only 50%. These results, and the withdrawal from the market of commercially prepared lyophilized myopic graft tissue, have led us to stop recommending epikeratoplasty for the treatment of myopia.
Medical Complications Grafts were removed from nine eyes of patients
less than eight years of age because of infection, necrosis, or opacification (Table 1). One graft was removed from the eye of a child over eight years of age. This patient was severely retarded and dislodged the graft by rubbing the eye.
Epithelial Defects: Epithelial defects are the most frequently encountered and serious medical complication of epikeratoplasty according to our study and others.3.4.14.18.21.22.30 Failure of the graft to become epithelialized predisposes the graft to infection, necrosis, vascularization, and opacification. 24 The early discovery and treatment of epi-
thelial defects is important. We identified microcornea, defined as a corneal
diameter of less than 10 mm, as a possible risk factor for the development of an epithelial defect. Four of the 22 (18%) procedures performed on eyes with microcornea developed epithelial defects; ten of 86 (12 %) normal sized eyes developed defects. Microcornea may predispose to defects in epithelialization because it is difficult to preserve epithelium at the corneal-scleral junction during preparation of the graft bed in these small eyes.
Medical complications related to a delay in epithelization occurred: a bacterial (Hemophilus influenza) corneal ulcer developed after one procedure, sterile melting of the graft occurred after five procedures, and graft or host stromal vascularization occurred after six procedures. Eight grafts were removed because of graft infection, necrosis, or opacification. Five of the six remaining grafts with epithelial defects had longlasting haziness at the site of the original defect. Persistent epithelial defects are a serious complication. In only one graft with a persistent epithelial defect did the complication resolve completely and result in a clear graft.
Modifications in epikeratoplasty technique have been introduced to facilitate epithelialization of the graft.22 For example, host epithelium is now removed with a 4 % cocaine solution or by mechanical debridement instead of using absolute alcohol. We make a conscious effort to retain a 1 mm rim of corneal epithelium at the limbus to provide a source of replicating epithelial cells for rapid epithelialization of the graft. We also perform a superficial keratectomy combined with a 1 mm intrastromal lamellar dissection of the host cornea to provide a tighter interface for graft adhesion and create a smoother transition zone between the graft and host tissue. We have also discontinued the routine use of bandage contact lenses. These lenses tend to adhere to the eye and cause a delay in graft epithelialization. 30
Because prolonged use of antibiotics can be toxic to the epithelium and allergic reactions to medications (three of Our patients developed allergic reactions to atropine ointment) may also impede epithelialization, we avoid the prolonged use of pharmacologic agents. Finally, the more streamlined the technique becomes, the less time the graft is exposed to heat produced by the operating microscope. A decrease in the time required to perform the procedure may be one reason the incidence of medical complications decreases with surgeon experience. As we have incorporated the above modifications into our epikeratoplasty pro-
J CATARACI' REFRACI' SURG-VOL 18, MAY 1992 275
cedure, we have observed that the grafts we have placed have epithelialized more rapidly. In a series of 75 epikeratoplasties using nonlyophilized graft tissue in children, Armesto et al. 34 reported only two cases of persistent epithelial defects suggesting an advantage in the use of nonlyophilized tissue. They also recognized, however, that other factors besides graft preparation may be responsible.
Interface Opacities: Opacities located between the donor and recipient corneas result from retention of particulate matter or from "cystic" proliferation of epithelial cell rests. 1 Interface opacities usually do not induce vascularization and may remain stable. 16,23,26-28,32
After one procedure in our study a cotton fiber was retained in the graft-host interface. This occurrence did not cause a ~fect in graft clarity, and no intervention is planned. After four (3.5%) procedures, epithelial inclusion rests developed at the graft-host interface. In two cases, the rests were peripheral to the visual axis and have remained stable. The other two interface opacities occurred in both grafts in a patient who received bilateral grafts; in each case surgical intervention was required because of progressive opacification of the visual axis. In one eye, the graft was removed and a new graft was placed without complication. In the other eye, the milky interface material was removed and a 4% cocaine solution was irrigated under the graft to poison the epithelial cells in the rest. On cytological examination the interface material was found to be devitalized epithelial cells (Figure 2). Following this procedure the graft-host interface became clear but two months later the milky fluid reaccumulated. Other authors have advocated treating epithelial rests at the graft-host
interface by lifting the graft edge, removing the opacity, and resuturing the edge of the graft. 1 ,23,26-28,32
To prevent the occurrence of epithelial cell rests, a 4 % cocaine solution should be applied to the host epithelium to facilitate the removal of the epithelium with a spatula; copious irrigation and meticulous suctioning are used to remove all vestiges of epithelial cells from Bowman's membrane and the cul-de-sacs.
Graft Vascularization: Vascularization of the host cornea, graft, or interface occurred in eight eyes. In six, the vascularization could be attributed to antecedent epithelial defects, and in five of the six the epithelial defects led to graft necrosis or infection (Figure 3). We found that risk factors for vascularization included microcornea, penetrating ocular trauma with vascularized corneal scars, multiple intraocular surgical procedures, and pre-existing uveitis.
To avoid graft vascularization, we suggest that topical administration of corticosteroids be used to inhibit immediate postoperative vascularization in eyes with vascularized corneal scars. Additionally, we recommend that sutures be removed within 10 to 14 days of graft placement because sutures that remain in place longer than two weeks are a stimulus for graft vascularization in children.
Graft Infection: The graft lenticule consists of a devitalized collagen matrix that must be epithelialized and populated with host keratocytes. 33 Until this occurs, the tissue remains devitalized and is prone to infection. In the nationwide study of 355 procedures, five of 36 grafts were removed because of infection. 15
Two of the patients with infections had Hemo-
Fig. 2. (Cheng) Three months after an epikeratophakia procedure, a five-year-old boy developed a milky interface opacity (left). This was aspirated and found to contain devitalized epithelial cells (right).
276 J CATARACf REFRACf SURC-VOL 18, MAY 1992
Fig. 3. (Cheng) This graft had a persistent epithelial defect which caused the graft to vascularize and become opaque.
philus influenza systemic infections (Figures 4 and 5). The frequent occurrence of H. influenza infections in children under five years of age should heighten suspicion that a graft infection may be caused by Hemophilus. Because of the prevalence of H. influenza infections, oral administration of amoxicillin has been recommended as part of routine care after epikeratoplasty.2,4 We question the efficacy of this practice. The prevalence of penicillinase-producing strains of H. influenza in children is high and such infections are likely to be
Fig. 4. (Cheng) Because of an upper respiratory infection, suture removal under general anesthetic was delayed. Three weeks after the epikeratoplasty procedure, the graft was infected and was removed. The underlying host cornea became clear after two months and regrafting was performed.
Fig. 5. (Cheng) This infection occurred 18 months after an epikeratophakia procedure in a three-year-old child. The graft was removed after unsuccessful attempts to treat the ulcer.
resistant to amoxicillin. Additionally, the concentration in the tears of a systemically administered antibiotic is probably not as effective in preventing infection as are topically administered antibiotic agents such as gentamicin or tobramycin. Both of these agents have bacteriostatic effects on H. influenza.
If a bacterial infection is suspected, cultures should be obtained and systemic and topical antibiotics should be given. If the host stroma is threatened, the graft .should be removed to prevent
Fig. 6. (Cheng) This graft underwent necrosis and became opaque. The graft was removed and the host cornea remained clear.
J CATARACT REFRACT SURG-VOL 18, MAY 1992 277
involvement of the host cornea. Graft Necrosis: Necrosis or melting of the epi
keratophakia graft was observed in five eyes and in each case an epithelial defect preceded the necrosis (Figure 6). Other authors have described finding evidence of proteolytic degradation of epikeratophakia tissue in association with persistent epithelial abnormalities. 28 We treat graft necrosis by removing the bandage contact lens if present, starting topical antibiotic therapy, and applying a pressure patch. We found, however, that once a melting process has begun, it is difficult to reverse. We were able to save only one graft. In grafts with extensive central melting that is unlikely to resolve and leave a clear visual axis, we recommend a timely decision on graft removal and replacement to minimize deprivation amblyopia in susceptible children.
Graft Haziness and Opacification: Graft haziness or opacification is usually the sequelae of other epikeratoplasty complications. 3 ,14 When there is an epithelial defect, necrosis, vascular ingrowth, infection, or prolonged stromal or lenticular swelling, a persistent haziness or opacification of the graft can occur. In our series, 15 grafts (13%) developed either persistent haziness (four grafts) or opacification (11 grafts). Children who have had epikeratoplasty and who are susceptible to developing amblyopia must be monitored carefully for the development of a graft haze. In three instances graft opacification necessitated removal of the graft.
We believe that persistent graft haze can also be the result of corneal and graft edema caused by endothelial dysfunction. Graft haziness was noted in many patients who had had multiple antecedent intraocular procedures or suffered ocular trauma. If endothelial cell density is decreased, the risk of haziness or opacification is increased.
Graft Dehiscence: Graft dehiscence occurred in the immediate postoperative period in three instances. In one ofthese, a mentally retarded patient with prominent eyes dislodged her graft two weeks after the sutures had been removed. It was later ascertained that this patient slept face down on the eye. Arm restraints and similar measures may be needed to prevent graft displacement. 4
We have documented the refractive and medical complications in a consecutive series of children treated with epikeratoplasty. We have attempted to identify the risk factors that lead to these complications. Some of the factors we identified, such as performing the procedure on children less than one year of age and treating patients with epikeratoplasty for myopia, have been previously
reported. 19 We also avoid treating children who are combative or profoundly retarded. We are reluctant to graft eyes with corneal diameters less than 10 mm as well as eyes with corneas which are suspected to have compromised endothelial function. Additionally, we avoid combining the procedure with cataract surgery.
By selecting patients carefully, experienced ophthalmologists who perform this procedure should enjoy increased success with epikeratoplasty in children.
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2. Morgan KS, Werblin TP, Asbell PA, et al. The use of epikeratophakia grafts in pediatric monocular aphakia. J Pediatr Ophthalmol Strabismus 1981; 18(6):23-29
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16. Vila-Coro AA, Goosey JD, Mazow ML, Martin DI. Epikeratophakia on pediatric traumatized corneas. J Pediatr Ophthalmol Strabismus 1987; 24:182-185
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17. Morgan KS, McDonald MB, Hiles DA, et al. The na- myopia removed from two patients. Ophthalmology tionwide study of epikeratophakia for aphakia in older 1986; 93:1502- 1508 children. Ophthalmology 1988; 95:526-532 26. Purcell JJ Jr, Brady HR. Intrastromal epithelial corneal
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20 . Uusitalo RJ, Lehtosalo J. Visual, refractive, and kera- 29. Lass JH, Stocker EG, Fritz ME, Collie DM. Epikerato-tometric results of epikeratophakia in children: a two- plasty: the surgical correction of aphakia, myopia, and year follow-up. Arch Ophthalmol1989; 107:358-363 keratoconus. Ophthalmology 1987; 94:912-925
21. Morgan KS, Collins CC. Combined cataract extraction 30. Steinert RF, Grene RB. Postoperative management of
and epikeratophakia in children. J Pediatr Ophthalmol epikeratoplasty. J Cataract Refract Surg 1988; 14:
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22 . Binder PS, Zavala EY. Why do some epikeratoplasties 31. McDonald MB, Kaufman HE, Aquavella JV, et al. The
nationwide study of epikeratophakia for myopia. Am J fail? Arch Ophthalmol1987; 105:63-69 Ophthalmol1987; 103:375-383
23. Morgan KS, Beuerman RW. Interface opacities in epi- 32. Stangler RA, Lindquist TD, Lindstrom RL. Interface keratophakia. Arch Ophthalmol1986; 104:1505-1508 hematoma after epikeratophakia. Am J Ophthalmol
