The nationwide study of epikeratophakia for aphakia in children

Non-Freeze Epikeratophakia in Children

We describe the use of unfrozen tissue lenses in 42 cases of epikeratophakia in children aged 2-14 years. Fourteen operations were performed in an aphakic eye, 28 in combination with congenital or traumatic cataract extraction. The tissue lenses, made from unfrozen donor cornea according to an original design, healed in 91.5% of cases. The tissue lens was removed when epithelial growth was inadequate on its surface. A five-year follow-up showed that correction within 3.0 D of emmetropia was achieved in 73.7% of the eyes. Preoperatively, mean keratometry readings were 43.5±0.2 D, increasing postoperatively to 53.6±0.8 D. Mean spherical equivalent at the spectacle plane increased by 9.6±0.9 D. Our investigations show the efficacy and safety of non-freeze epikeratophakia in the correction of pediatric aphakia.

Epikeratophakia in children

In the past two years 29 patients (ages 9 months to 15 years) received 37 epikeratophakia grafts. 91.1 percent of the original surgeries were successful. The average change in refractive error was 16.7 diopters, and the average spectacle overcorrection was +0.2 diopters. We have obtained good visual results in our very young patients were follow-up is already over 1 year. We demonstrated also some improvement in visual acuity in older children especially those with traumatic or secondary cataracts. The study demonstrates that we can add an average of +17.1 diopters with an epikeratophakia graft and that the amount of correction obtained is remarkable predicted.

Epikeratoplasty for adult and pediatric aphakia, myopia, and keratoconus: the Massachusetts Eye and Ear Infirmary experience

Between February, 1985 and February, 1987, 49 eyes of 47 patients underwent epikeratoplasty for one of the following indications: adult aphakia (21 eyes; 20 patients), pediatric aphakia (10 eyes; 10 patients), myopia (7 eyes; 6 patients), and keratoconus (11 eyes; 11 patients). Follow-up at least 12 months (average = 18 months) is available for all 49 eyes. Of 49 eyes, 44 (90%) were anatomically successful with an intact, clear lenticule at least 12 months post-operatively, with no significant difference between the four groups (adult aphakia = 90%, pediatric aphakia = 90%, myopia = 86%, and keratoconus = 91%). The functional success rate, however, was 91% for keratoconus, 81% for adult aphakia, 80% for pediatric aphakia, and only 43% for myopia. We conclude that epikeratoplasty can be an effective tool in the treatment of carefully selected patients with adult or pediatric aphakia and keratoconus, but has only limited applicability in the management of myopia.

Refractive surgery: through the looking glass

Historically, surgical procedures designed to change the refractive power of the cornea have been controversial at their inception, gaining acceptance only with time and study. From intraocular lenses to corneal remodelling with the excimer laser, and numerous procedures in between, including radial keratotomy, epikeratophakia, incisional keratotomy for astigmatism, and hydrogel and polysulfone implants, ophthalmologists have balanced the risks and benefits for their patients to produce the maximum benefit at the least cost. The present status and future potential of each of these are assessed as they appear today. There is no question that progress will continue, and that our patients will be the beneficiaries of our ongoing interest in improving older procedures and developing new techniques for the correction of refractive errors.

Ten-year follow-up of epikeratophakia for the correction of high myopia

OBJECTIVE

To determine the long-term functional results of epikeratophakia for myopic patients.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty-two patients (32 eyes; average age, 43+/-6 years) who underwent epikeratophakia surgery for high myopia. Mean preoperative myopia was -18.74+/-9.16 diopters (D; range, -7 D to -49 D). Follow-up was 12+/-2 years.

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), change in mean keratometry, visual acuity under glare conditions, BCVA versus potential acuity meter reading, and patient satisfaction with the visual outcome.

RESULTS

Mean preoperative UCVA increased from 20/800+/-20/400 (range, counting fingers-20/400) to 20/80+/-20/200 (range, 20/250-20/32) in 24 eyes. Mean preoperative BCVA of 20/32+/-20/64 increased only in five eyes, whereas six eyes had no change and 18 eyes had a more than one line loss of Snellen BCVA. Mean preoperative keratometry reading decreased from 43.67+/-0.90 D (range, 41.0-46.25 D) to 37.40+/-2.92 D (range, 29.43-47.68 D). In the presence of glare, mean BCVA decreased to 20/100+/-20/100 (range, counting fingers-20/32). Potential acuity meter (PAM) readings were significantly (P<0.05) higher than BCVA. Mean PAM reading was 20/25+/-20/100 (range, 20/100-20/16). Seven patients (11 eyes) were extremely satisfied with the operative result more than 10 years after the operation, whereas four patients (four eyes) were not satisfied at all.

CONCLUSIONS

Epikeratophakia for the correction of myopia improved UCVA significantly, but BCVA decreased. The removal of the lenticules in patients who were not satisfied with their visual acuity was uncomplicated, and acceptable vision could be achieved with either contact lenses or intraocular lens implantation.

Role of posterior capsulotomy with vitrectomy and intraocular lens design and material in reducing posterior capsule opacification after pediatric cataract surgery

PURPOSE

To study the effect of primary posterior capsulotomy with anterior vitrectomy (PPC + AV) and intraocular lens (IOL) design and material on the development of posterior capsule opacification (PCO) after pediatric cataract surgery.

SETTING

Tertiary care institution in India.

PATIENTS

Sixty-four eyes of 52 children ranging in age from 3 months to 12 years who had cataract extraction with IOL implantation were prospectively evaluated for a minimum postoperative period of 2 years.

METHODS

Thirty-two eyes received a hydrophobic acrylic lens with a truncated, square edge and 32, a single-piece poly(methyl methacrylate) (PMMA) lens that was not heparin surface modified. Sixteen eyes in each IOL group had PPC + AV; in the remaining 16 eyes in each group, the posterior capsule was left intact.

RESULTS

Postoperatively, 25 eyes in the intact capsule group and 5 in the PPC + AV group developed PCO; the difference between groups was significant (P<.05). Of eyes with an intact capsule, 12 with an acrylic IOL and 13 with a PMMA IOL developed PCO (P>.05). In the PPC + AV group, 2 eyes with an acrylic IOL and 3 with a PMMA IOL developed PCO (P>.05). Overall, 14 eyes with an acrylic lens and 16 eyes with a PMMA lens developed PCO (P>.05). After surgery, there was a significant short-term delay in the development of PCO in the acrylic group (14 eyes; mean 6.66 months +/- 1.57 [SD]) compared to the PMMA group (16 eyes; mean 3.16 +/- 0.83 months) (P<.05).

CONCLUSIONS

It is the management of the posterior capsule rather than IOL design and material that influences the incidence of PCO after cataract surgery in children. Development of PCO in the postoperative period was delayed with a hydrophobic acrylic IOL with square edges compared with a PMMA lens without square edges.

Corneal Sensitivity 10 Years After Epikeratoplasty

PURPOSE

To assess corneal sensitivity in patients 10 or more years after epikeratoplasty for myopia, aphakia, hyperopia, and keratoconus.

METHODS

A total of 45 eyes of 33 patients (age range at examination 33 to 55 yr) were included in the study. Corneal sensitivity thresholds using an electromagnetic aesthesiometer (Draeger) were measured at various locations on the lenticule and the recipient cornea. Measurements were evaluated regarding the corrective purpose, surgical technique, age, and gender of the patients and the area of measurements.

RESULTS

The mean corneal sensitivity threshold in the center of the epikeratoplasty lenticule was significantly lower than on the peripheral recipient cornea (320.0 +/- 365.1 x 10(-5) N versus 0.1 +/- 0.5 x 10(-5) N). Corneal sensitivity at the 3 and 9 o'clock positions was significantly higher compared to the values at the 6 and 12 o'clock positions on the lenticule. No correlations of these values with age, gender, type, and primary indications for the surgery were observed.

CONCLUSIONS

These results indicate a relative hypesthesia of the epikeratoplasty lenticule as compared to the peripheral host cornea, even 10 years after surgery. In our patients no clinically significant changes were observed that could be attributed to the reduced sensitivity over this follow-up period.

Phakic posterior chamber intraocular lens for the correction of anisometropia and treatment of amblyopia

PURPOSE

To assess the potential visual benefits of posterior chamber phakic intraocular lens implants in eyes of children with anisometropic amblyopia.

METHODS

In a prospective study, three girls 9, 14, and 18 years old with high anisometropia and deep amblyopia were included in this study. The phakic posterior chamber intraocular lens (ICL; STAAR Surgical AG, Nidau, Switzerland) was used to correct the anisometropia. This intraocular lens was inserted in the anterior chamber through a 3.0-mm temporal clear cornea incision and manipulated into the posterior chamber using an iris manipulator. A peripheral iridectomy was performed using the Ocutome Probe (Storz; Premiere, St. Louis, Missouri). Local therapy with corticosteroids and antibiotics were prescribed for 2 weeks, and patients were followed regularly for a period of 6 to 9 months.

RESULTS

In the three amblyopic eyes of the three patients, the preoperative best-corrected visual acuity of 6/30, 6/60, and 6/30 improved, to 6/7.5 (20/25), 6/30 (20/100), and 6/15 (20/50), respectively, 6 months after the surgery. Binocular functions with development of fusional abilities and stereopsis were observed in two of these patients after the intraocular lens implantation. In the third patient, the fusional abilities developed only after surgical correction of the exotropia. The intraocular pressure remained within normal limits, and there was no significant change in the corneal endothelial cell count during the period of follow-up. No major intraoperative or postoperative complications were observed, except for a temporary pigment dispersion.

CONCLUSIONS

Implantation of phakic posterior chamber intraocular lenses may be beneficial for the treatment of amblyopia in children with anisometropia. Although additional cases and long-term follow-up observations are necessary, it appears that amblyopia may be overcome by the use of posterior chamber phakic intraocular lens implants, even in eyes of children beyond the age generally considered to be responsive to anti-amblyopic treatment.

Advances in refractive surgery: 1975 to the present

PURPOSE

To review the major advances in the field of refractive surgery occurring over the past 25 years.

METHODS

Literature review.

RESULTS

The major developments in refractive surgery over the past 25 years are reviewed.

CONCLUSIONS

The past 25 years have witnessed great changes in refractive surgery. As a result of advancements in technology, instrumentation, and technique, we have seen improvements in the treatment of all types of ametropias. In this article, we review some of the successes and failures of the past quarter-century.

Long-term outcome of epikeratophakia

PURPOSE

To assess the long-term outcome of epikeratophakia.

SETTING

National center for pediatric ophthalmology (The Children's Hospital) and ophthalmology department in a regional general hospital (Waterford Regional Hospital), Republic of Ireland.

METHODS

A retrospective clinical review was carried out of 25 eyes (20 patients) with epikeratophakia performed over 10 years. Eyes were assigned to a children's group (Group 1) or an adult group (Group 2), depending on patient age at the time of surgery, and assessed with respect to indication for surgery, visual acuity, condition of the implanted lenticule, complications, refraction, and corneal topography. Histological analysis was performed on 1 removed lenticule.

RESULTS

Mean follow-up of all patients was 7.3 years (median 6.8 years; range 4.0 to 10.0 years). Most eyes (n = 18) were contact lens intolerant. Freeze-dried lenticules were implanted in all cases, and all but 1 had stable visual acuity from the early postoperative period to last follow-up. In Group 1 (n = 10), most eyes had a visual acuity of 6/36 or worse preoperatively with an improvement of 1 or more lines in 4 eyes. In Group 2 (n = 14), at last follow-up most eyes retained good or improved visual acuity by 1 or more lines. Most grafts were clear or had insignificant opacities outside the visual axis. The overall complication rate was 12%, with the most serious complication being significant induced astigmatism requiring removal of 1 epigraft. Mean induced astigmatism was 2.50 diopters (D) (median 2.00 D; range 1.00 to 6.00 D), which was accurately predicted within +/- 1.00 D by corneal topography in 14 of 19 eyes. Histology demonstrated infiltration of the implanted lenticule by host keratocytes.

CONCLUSION

Epikeratophakia, a reversible procedure with a low complication rate, resulted in stable visual acuity with good lenticule condition and minimal induced regular astigmatism after long-term follow-up.

Traumatic Aphakia Treated with an Iris Prosthesis/Intraocular Lens or Epikeratophakia

OBJECTIVE

We retrospectively analyzed the visual results and postoperative complications associated with severely traumatized eyes in which aphakia was corrected with epikeratophakia or a sutured iris prosthesis/intraocular lens (IOL).

METHODS

Fourteen eyes (14 patients) with traumatic aphakia and severe anterior segment complications were corrected either with epikeratophakia or a sutured iris prosthesis/IOL. All eyes lacked lens capsule or iris support for an IOL. The surgical technique of implanting an iris prosthesis/IOL employed transcleral suturing in the ciliary sulcus combined with penetrating keratoplasty.

RESULTS

In the eight eyes treated with epikeratophakia, four (50%) had spectacle-corrected visual acuity of 20/40 or better. Almost all of these eyes lost one or two Snellen lines of baseline spectacle-corrected visual acuity. Few complications occurred after epikeratophakia; none were severe. Of six eyes with penetrating keratoplasty and a sutured iris prosthesis/IOL or a sutured posterior chamber IOL, two (33%) achieved a visual acuity of 20/40 or better. In the IOL group, severe complications occurred, including posterior dislocation of the lens and secondary glaucoma.

CONCLUSIONS

The surgical correction of aphakia in severely traumatized eyes requires specialized surgical techniques. Epikeratophakia is a low-risk operation that can be performed in eyes in which an IOL is contraindicated. The iris prosthesis/IOL technique results in good cosmetic results; however, due to complications, this technique should be used with caution.

Long-term Follow-up of Pediatric Epikeratophakia

BACKGROUND

Epikeratophakia is a potentially reversible corneal surgical procedure that can correct refractive errors in children who are aphakic and poor candidates for intraocular lens implantation. The correction of aphakia in the pediatric population poses specific problems because of associated amblyopia.

METHODS

The clinical records of 61 consecutive patients (82 eyes) treated for pediatric aphakia by epikeratophakia were reviewed retrospectively with a follow-up of 3 to 5 years. For the purpose of analysis, the patients were divided into seven groups.

RESULTS

The overall success rate for epikeratophakia was 92%, but with repeated surgery, the patient success rate was 93%. The average refractive error at 1 year was + 0.10 diopters (D). At 1 year, 68% of eyes had a refraction within 1 D of emmetropia. In these growing eyes, we documented an average myopic shift of -0.40 D during 4 years. A myopic shift occurred in 30.2% and a hyperopic shift in 9.4% of eyes. Spectacle-corrected visual acuity at 3 years showed 36% of eyes seeing 20/40 or better. Visual acuity results in different groups varied with the timing of epikeratophakia, density of amblyopia and parents' ability to maintain the patching schedule. The most encouraging results came from the treatment of monocular traumatic cataracts. In this group, 31% achieved visual acuities of 20/40 or better and 85% achieved 20/100 or better at final examination. Those with incomplete congenital cataracts also showed favorable results: 39% achieved 20/40 or better at final examination.

CONCLUSIONS

Follow-up of 3 to 5 years demonstrated that epikeratophakia can correct refractive errors safely and successfully in aphakic children, either as a primary procedure, or as a secondary procedure after cataract extraction.

Epithelial Inclusion Cysts Following Epikeratoplasty

BACKGROUND

Epikeratoplasty for keratoglobus performed to tectonically support the thin globular cornea may have complications such as interface opacities.

METHODS

We report the case of a patient with persistent interface opacities and epithelial cysts following epikeratoplasty for keratoglobus that were treated primarily by washouts and repeated argon laser photocoagulation.

RESULTS

Interface opacities led to massive epithelial inclusion cysts. Direct removal of these cysts and placement of a new lamellar graft resulted in a favorable outcome.

CONCLUSION

Massive epithelial inclusion cysts may develop in the lamellar interface after epikeratoplasty. Direct surgical removal was successful.

Epikeratoplasty for Myopia: 2-year Results and a Proposed Nomogram

BACKGROUND

Epikeratoplasty for myopia is a relatively safe and reversible surgical technique that can result in large refractive corrections. However, it is also claimed that long-term stability and predictability are not satisfactory due to refractive regression and undercorrection.

METHODS

In an effort to improve predictability and stability of epikeratoplasty for myopia, we followed 24 cases for 2 years and isolated factors affecting the postoperative refractive results.

RESULTS

We found that better refractive results were achieved at 24 months postoperatively for cases in which the power of preoperative myopia was lower. Our investigations also disclosed no significant correlation between the surgical outcome at 24 months and patients' sex, age, and preoperative keratometric readings.

CONCLUSION

On the basis of our observations, we propose a new nomogram where higher powers of minus keratolenses, compared to the traditional prescription chart, should be selected for those with high preoperative myopia to result in improved long-term results with epikeratoplasty for myopia. This nomogram has not yet been clinically tested.

Intraocular lens implantation in children in the West Bank and Gaza

In order to evaluate the efficacy and safety of intraocular lens (IOL) implantation in paediatric aphakia, we reviewed the records of a consecutive series of 40 children, under 15 years of age, who had IOLs inserted for congenital and developmental cataracts between September 1990 and December 1992. Visual results and lens-induced complications were evaluated in 67 eyes with a mean follow-up of 27 months (range 12-38 months). In 52 eyes the cataract was removed by limbal lens aspiration and in 15 eyes by pars plicata lens aspiration. One-piece PMMA Sinskey-type posterior chamber implants were used in all cases. Sixty-three eyes had primary and 4 eyes secondary implants. Seventeen (49%) of 35 eyes with congenial cataract and 25 (78%) of 32 eyes with developmental cataract achieved a visual acuity of 6/18 or better. Marked anterior uveitis with pupillary membrane formation occurred in 9 (13%) of the 67 eyes. Visually significant posterior capsule opacification occurred in 5 (28%) of the 18 eyes with intact capsule. Our results demonstrate the suitability of IOL implantation in children from an area of low socioeconomic background, and suggest that IOL implantation is an effective and safe procedure for correction of paediatric aphakia. This may have implications for similar populations.

Histopathological findings in failed human epikeratophakia lenticules

Six human epikeratophakia lenticules were removed 1 to 23 months after refractive keratoplasty for aphakia (n = 2) and myopia (n = 4). The myopic group included one epi-lenticule treated with ArF-excimer laser for hyperopia. Reasons for removal were epithelial defect (n = 4), edema of host cornea (n = 1), and overcorrection (n = 1). The epi-lenticule stroma showed centrally a regular fibrillar structure with a low keratocyte density. Electron microscopy (n = 1) revealed preserved cytoplasmic organelles and nuclear appearance. Mononuclear cells were absent. Polysaccharide was demonstrated in the stroma. Bowman's layer was normal without breaks. The epithelium had variable thickness. In the peripheral wound region stromal and epithelial irregularities were evident.

Posterior chamber lens implantation for primary repair of corneal lacerations and traumatic cataracts in children

Children older than 3 years of age rarely tolerate contact lenses for unilateral surgical aphakia. This problem is even more pronounced following repair of corneal lacerations or perforations that are associated with traumatic cataracts. Even if surgery is successful, such eyes are functionally doomed because of deep anisometropic amblyopia. We evaluated prospectively in 15 children (3 to 8 years) the results of combined operation of corneal repair, aspiration of traumatic cataract, and primary posterior chamber lens implantation. Postoperative occlusion treatment was carefully monitored. Follow up ranged from 6 to 60 months, with an average of 39.2 months. The final best corrected visual acuity at the patient's last visit was 20/40 or better in 11 of 15 children (73.3%). The most frequent complication was a nonfunctional pupil due to traumatic iris damage or posterior synechiae in 13 cases. The most visually significant complication was posterior membrane formation and/or posterior capsule opacification, which required additional surgeries in six children.

Pseudophakia for traumatic cataracts in children

PURPOSE

The purpose of this prospective study is to evaluate the postoperative visual acuity, refractive error, intraocular pressure, and status of the posterior capsule in children with traumatic cataracts who undergo extracapsular cataract extraction and insertion of a posterior chamber lens.

METHODS

Extracapsular cataract extraction and primary endocapsular fixation of a posterior chamber lens implant were performed in eight children (age range, 4-17 years) with unilateral traumatic cataracts.

RESULTS

There were no intraoperative complications, and seven of eight eyes achieved 20/40 or greater spectacle visual acuity during an average follow-up interval of 10 months (range, 5-20 months). The average postoperative spherical equivalent refractive error was +0.33 diopter (D) (range, -2.25 to +2.12 D); the average postoperative anisometropia was approximately 1 D (range, 0-2.25 D). In one patient, a coagulase-negative staphylococcal endophthalmitis developed 10 days after surgery. In three eyes that had opacified posterior capsules, YAG laser capsulotomy was performed.

CONCLUSIONS

These preliminary results suggest that intraocular lens (IOL) implantation may be a safe and effective method of optical correction for children with traumatic cataracts.

Epithelial interface cysts after epikeratophakia

BACKGROUND

Epithelial interface cysts have been occasionally observed after lamellar keratoplasty. The authors report the incidence, clinical significance, and management of this complication in epikeratophakia patients.

METHODS

From August 1987 to January 1991, 108 consecutive patients undergoing epikeratophakia entered a prospective study aimed at evaluating both clinical results and changes in corneal physiologic parameters. After an average hospitalization of 6 days, all patients underwent complete ophthalmologic examinations at regular intervals after surgery. All postoperative complications, including the development of epithelial interface cysts, were recorded and photographed.

RESULTS

Over a 3-year period, epithelial interface cysts were observed in 8 eyes, with an overall incidence of 7.4%. All cysts originated under the periphery of the epilens. In five patients, the cysts enlarged centripetally but eventually ceased to grow, causing no visual impairment. In two patients, after an initial increase in size the cysts slowly regressed and finally disappeared. In only one patient, a cyst migrated over the visual axis, thus necessitating surgical removal. The cyst did not recur during an observation time of 18 months after debridement, allowing full recovery of visual acuity.

CONCLUSION

The incidence of epithelial interface cysts after epikeratophakia is relatively high. Because of their peripheral location and self-limited growth, the clinical significance of this complication is low. The possibility of spontaneous regression of the cysts supports a conservative approach, as long as the visual axis is not affected. Surgical removal is possible without compromising the epi-lens and is compatible with an excellent visual outcome.

Pediatric aphakic contact lens wear: rates of successful wear

Two hundred thirty-eight consecutive patients with pediatric cataracts were fitted with a variety of aphakic contact lenses after cataract extraction. Thirty-nine patients did not return for follow up. Of the remaining 199 patients, 40 discontinued contact lens wear. None of the 78 patients with unilateral or bilateral acquired cataracts discontinued contact lens wear due to problems wearing their lenses, although nine discontinued contact lens wear due to poor vision or difficulty maintaining amblyopia treatment. Twenty-two of 84 patients with unilateral congenital cataracts discontinued lens wear, six directly due to difficulties wearing lenses. Sixteen had poor vision in their aphakic eye and inability to maintain patching for amblyopia. Eight of 37 patients with bilateral congenital cataracts discontinued lens wear because of problems wearing their lenses, and one other discontinued lens wear because of poor vision. In summary, 26 of 40 patients (out of a total of 199) that discontinued aphakic contact lens wear did so because of poor vision, while only 14 did so because of difficulties wearing the contact lenses. Eleven of these 14 patients were able to wear aphakic spectacles in lieu of contact lenses. This study shows that most pediatric patients with cataracts fail at treatment because of problems related to treatment of amblyopia, and not problems related to the fitting and wearing of contact lenses.

Risk factors for complications following pediatric epikeratoplasty

We studied the prevalence and types of complications that occurred in children treated with epikeratoplasty to identify risk factors. A review of the clinical records of 88 consecutive patients (106 eyes; 114 procedures) revealed that no complications occurred in 58 grafts (54%). Refractive complications (refractive error greater than 3.00 diopters spherical equivalent from emmetropia or astigmatism greater than 3.00 diopters) occurred in 30 eyes (28%). Medical complications occurred in 22 eyes (19%); these included epithelial defects (14 grafts), interface opacities (six grafts), graft vascularization (eight grafts), graft infection (two grafts), graft necrosis (five grafts), graft haziness (four grafts) or opacification (11 grafts), and graft dehiscence (three grafts). Eleven grafts (10%) were removed and five eyes received new grafts. Epikeratoplasty in children will be more successful if risk factors such as patient age less than one year, microcornea, corneal endothelial cell dysfunction, mental retardation, and combining the procedure with cataract surgery are avoided.

Physiologic analysis of corneal healing after epikeratophakia

The evaluation of epithelial permeability, stromal transparency, and endothelial cell density is essential to determine the resumption of normal function in each corneal physiologic unit after refractive surgical procedures. The authors report the results of a prospective study conducted in 55 consecutive patients undergoing epikeratophakia using prelathed, lyophilized tissue lenses. Epithelial permeability was evaluated by means of fluorophotometry preoperatively and 1, 2, 4, 8, 12, 24, and 52 weeks after epikeratophakia. With few exceptions, Scheimpflug photography also was performed at the same examination times to assess stromal optical density. Endothelial cell counts were performed in each patient preoperatively and between 6 and 12 months postoperatively. The epithelial barrier function resumed normal values within 8 weeks after epikeratophakia. The optical density of both donor lenticule and recipient corneas was initially increased but returned to values comparable with those of unoperated corneas by 12 weeks postoperatively. Endothelial cell density was not affected by epikeratophakia. These results confirm the authors' preliminary observation that epikeratophakia allows a relatively quick recovery of normal corneal functions and should prompt investigators to demonstrate the safety of other refractive surgical procedures in a similar way.

Epikeratophakia for high myopia

A cryo-technique for production of corneal epi-lenses has been developed. During the manufacturing procedure the anterior surface of the tissue is moulded and the posterior surface cut with a microtome. After cutting, the epi-lenses are stored for days to weeks in an organ culture medium. Twelve eyes in 10 patients have been treated with epikeratophakia for high myopia (greater than -7 D). In all eyes, epithelialization was complete within one week, and at follow-up 3-18 months after the operation all epi-lenses were clear. The average refractive change in spherical equivalents was 9.7 +/- 4.4 D. All eyes obtained better uncorrected visual acuity, and no eyes lost more than one line of the best corrected visual acuity. At the time of follow-up, the patients' native cornea had regained normal hydration, whereas the epi-lenses did not thin as much as expected.

Visual performance after aphakic epikeratoplasty

While good visual acuity and refractive results after epikeratoplasty for aphakia have been reported, particularly for adults and older children, limited detailed information on the nature of the resulting vision is available. We have evaluated the visual performance of seven aphakic subjects corrected by epikeratoplasty by measuring contrast sensitivity, with and without the presence of glare. These results were compared with those for other aphakic corrections, namely spectacles (n = 5 eyes), contact lenses (n = 5 eyes), or intraocular lens implantation (n = 5 eyes). There were statistically significant differences among these four aphakic correction types (p = 0.0330), with a consistent trend for diminished visual performance after epikeratoplasty. Threshold elevations occurred in the presence of glare, but they were not statistically different between the groups (p = 0.1631). Based on these visual assessments, epikeratoplasty does result in statistically significant visual losses. Despite this, it may still offer an acceptable alternative to other managements of the aphakic patient when those others are contraindicated.

Epikeratoplasty with nonlyophilized tissue in children with aphakia

We studied 75 epikeratoplasty procedures using nonlyophilized tissue performed by eight ophthalmic surgeons in 70 eyes (47 patients) to correct for aphakia in children less than 8 years of age (mean age, 3.4 +/- 2.1 years). Of the 47 patients in the study, 24 were girls and 23 were boys; 23 patients had bilateral surgery. Seven of the epigrafts required removal; two were not replaced, and five underwent successful repeat epikeratoplasty. Overall, the success rate (that is, the percentage of epigrafts that remained optically and functionally clear throughout the course of this study) for the epikeratoplasty procedure was 89% (62 of 70 eyes) for initial surgery and 96% (67 of 70 eyes) for repeat surgery. The average spherical equivalent was +14.4 +/- 3.7 diopters preoperatively and +0.3 +/- 2.9 diopters one year after the operation. One year after the final surgical procedure, 42 of 56 eyes (75%) were within 3 diopters of emmetropia. In the 29 verbal patients, best-corrected visual acuity was 20/100 or better in 25 (86.2%) one year after the operation.

Epikeratoplasty for keratoglobus associated with blue sclera

Patients with keratoglobus and blue sclera as part of a generalized connective tissue disorder are at a high risk of developing corneal perforations either spontaneously or after mild trauma. Six patients (6 eyes) between the ages of 2 and 16 years of age (mean, 7.5 years) with keratoglobus, blue sclera, hypermobile joints, and consanguineous parents were treated by epikeratoplasty, using commercially prepared 12.5-mm lenticules. Surgery was performed for tectonic support and/or visual improvement and was successful in five of six patients with a follow-up period of 11 to 27 months (mean, 21 months). One lenticule was removed because the epithelium did not heal. Peripheral interface opacities occurred in three patients.

Visual acuity in monocular pediatric aphakia: does epikeratophakia facilitate occlusion therapy in children intolerant of contact lens or spectacle wear?

Twenty-two children had a monocular cataract extracted between 1981 and 1986. Twelve of these patients eventually tolerated a monocular contact lens or anisometropic spectacle wear. Eleven patients initially would not tolerate conventional therapy, and epikeratophakia was performed. Of the 12 patients tolerating a contact lens or spectacles, eight (67%) now see 20/60 or better, and six (50%) see 20/40 or better. Only one (10%) of the patients maintaining the epikeratophakia graft developed vision as good as 20/70. Epikeratophakia did not facilitate occlusion therapy for amblyopia. The critical factor in the development of good vision following monocular cataract extraction was the patient's willingness to patch the better eye, not the method of correcting the refractive error.

Bilateral phakic hypermetropic epikeratoplasty for accommodative esotropia

Optical correction of high hypermetropia with glasses is the primary treatment for accommodative esotropia. These glasses are often poorly accepted by adolescents and young adults for they are cosmetically undesirable, heavy, and esotropia occurs with their removal. We report an 11 1/2-year-old, physically mature female with high hypermetropia and accommodative esotropia corrected to orthophoria with glasses who was unable to be weaned from her glasses. She became intolerant to glasses wear, refused contact lenses, and was treated successfully with bilateral phakic hypermetropic epikeratoplasty. Two years postepikeratoplasty her visual acuity is 20/40 and 20/20 uncorrected and the vision in the amblyopic right eye has remained at its maximum preoperative level. She is orthophoric at distance and has a 2 prism diopter monofixational esophoria at near without glasses. Epikeratoplasty is an option in the treatment of accommodative esotropia for patients who are past the amblyopia forming age, have a stable angle of strabismus, and who require their full hypermetropic optical correction to maintain orthophoria.

Evaluation of functional and morphologic parameters of the cornea after epikeratophakia using prelathed, lyophilized tissue

Up to now, the attention of ophthalmic surgeons has been focused mainly on the clinical results of epikeratophakia, demonstrating its safety, relative predictability, and capability of correcting a wide range of refractive errors. However, no prospective study has ever been undertaken to evaluate the influence of epikeratophakia on various physiologic and morphologic parameters of the cornea. The authors investigated some of these parameters prospectively in eight consecutive patients undergoing epikeratophakia with prelathed, lyophilized tissue. Fluorophotometric evaluation of the epithelial barrier function, corneal densitometry by means of Scheimpflug photography, and endothelial specular microscopy were performed preoperatively and 2, 4, 8, 12, and 24 weeks after epikeratophakia. The epithelial barrier function was shown to return to normal 4 weeks after surgery. The optical density of both the epi-lenses and the host corneas increased early after surgery, but was comparable to that of unoperated corneas 6 weeks postoperatively in all cases but one. The endothelial cell density was not altered by surgery in any patient. Despite the limited number of patients, this study indicates that most functional and morphologic parameters of the cornea are normal as early as 6 weeks after epikeratophakia in most cases.