Risk factors for complications following pediatric epikeratoplasty

Development of retrocorneal membrane following pig-to-monkey penetrating keratoplasty

Recent reports of long-term survival after wild-type (WT) pig-to-monkey corneal xenotransplantation are encouraging. We experienced the rapid development of retrocorneal membranes, a rare complication after corneal allotransplantation (although seen in infants and young children). The original specific aim of the study was to determine the factors associated with successful (young) pig corneal transplantation in monkeys. However, when it was obvious that retrocorneal membranes rapidly developed, our aims became to determine the factors involved in its development after both WT and Genetically engineered (GE ) pig corneal xenotransplantation and to investigate the characteristics of the retrocorneal membrane. Rhesus monkeys were recipients of penetrating keratoplasty using WT and GE pigs (n=2, respectively, 1-3 months old). Local/systemic steroids were administered for 3 months. Grafts were evaluated by slit lamp for corneal transparency, edema, and neovascularization. Hematoxylin and eosin, Masson trichrome staining, and immunohistochemical analysis were performed. Gal staining was also carried out to distinguish the origin of the membrane. All penetrating keratoplasty recipients developed fibrous retrocorneal membranes in the early post-transplantation period, regardless of whether the graft was from a WT or GE pig. There were no features of rejection, with no cell infiltrate in the graft or anterior chamber during the three-month follow-up. There was no difference in the clinical course between the two groups (WT or GE corneas). Immunohistochemistry indicated that the retrocorneal membranes were CK negative, α-SMA positive, and vimentin positive, suggesting that they were of fibrous (keratocytic) origin. Also, the membrane was Gal positive, suggesting that it is derived from pig cornea. Following pig-to-monkey corneal xenotransplantation, we report that retrocorneal membranes are derived from donor pig keratocytes. Prevention of retrocorneal membranes will be necessary to achieve successful corneal xenotransplantation.

Corneal refractive surgery: past to present

There have been many historical corneal refractive techniques and procedures developed over the years. From early techniques of radial keratotomy to modern excimer laser techniques, the field of refractive surgery is one of the most rapidly developing in ophthalmology. This review details the historical aspects of the many early techniques up to current techniques used on millions of eyes around the world.

Infectious keratitis following keratoplasty

Infectious keratitis following corneal transplantation is one of the leading causes of failure of a corneal graft. The incidence of graft infection is variable, with developing countries having a higher incidence. The majority of the graft infections occur within 1 year of the corneal transplantation. Suture-related problems and persistent epithelial defect are the most common risk factors predisposing to graft infection. Pneumococcus species and Staphylococcus aureus have been found to be the commonest microorganisms in the developed world, whereas Staphylococcus epidermidis is the most often detected microorganism in corneal graft infection in the developing world. The early identification of predisposing risk factors in patients and their appropriate management at the earliest may prevent the occurrence of graft infection and might improve graft survival. Visual prognosis in eyes with post-keratoplasty graft infection is poor even after optimal therapy and there is a high rate of graft decompensation.

Microbial Keratitis Following Lamellar Keratoplasty

OBJECTIVE

To determine the predisposing factors, etiologic agents, and clinical and visual outcomes in infectious keratitis following lamellar keratoplasty (LK).

METHODS

One hundred thirty-five eyes (135 patients) that had undergone LK were retrospectively analyzed for the occurrence of infectious keratitis following LK. The parameters evaluated were predisposing factors, seasonal variation, indications and type of LK, time interval between LK and infection, site and depth of infection, etiologic organisms, type of treatment, outcome in terms of graft status, secondary surgery, visual acuity, and the donor tissue profile.

RESULTS

The incidence of infectious keratitis following LK was 11.11%. The most significant predisposing factor was persistent epithelial defect (3 eyes) and suture abscesses (3 eyes). Most cases occurred between May and August (9/15). Twelve cases developed infection within 2 weeks of surgery (80%). Seven cases (7/15) occurred with onlay grafts, 6 with inlay grafts, and 2 with large-diameter LK. Cultures of corneal scrapings were positive in 11 eyes (73.3%), and the most common isolated organism was coagulase-negative Staphylococcus (CNS). Only 2 eyes responded to medical therapy, and graft sloughing occurred in 9 cases. Six eyes underwent penetrating keratoplasty to either salvage the integrity of globe or for visual rehabilitation of cases where infection resulted in corneal opacity.

CONCLUSIONS

Infections after LK may not be amenable to antimicrobial therapy and may necessitate the removal of the graft or a therapeutic penetrating keratoplasty.

High levels of binocular function are achievable after removal of monocular cataracts in children before 8 years of age

OBJECTIVE

To investigate the visual acuity and binocular function results achieved in children who had monocular cataracts removed before 8 years of age.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Clinical records of 171 patients who underwent a unilateral cataract removal between January 1986 and 1996 were reviewed retrospectively. Seventy-four eyes were included in the study: 19 congenital, 11 developmental, 19 posterior lenticonus, 19 traumatic, and 6 complicated cataracts. Patients with less than 2 years of follow-up; eyes with cataracts resulting from retinoblastoma; prematurity; and those associated with dense corneal scars, lens dislocation, and persistent hyperplastic primary vitreous were excluded.

INTERVENTION

Visual acuity was measured by means of age-appropriate tests such as the fixation pattern, Allen object recognition cards, isolated optotypes with the Sheridan Gardiner test, and Snellen letters. Sensory fusion was assessed with the Worth 4-dot test, and stereo acuity was assessed with the Titmus stereo test.

MAIN OUTCOME MEASURES

Cataracts were classified regarding type, extent, age at onset, duration of the opacity, age at surgery, method of removal, development of secondary membrane, form of optical rehabilitation, and presence of strabismus. Visual acuity levels between 6/6 and 6/12 were considered "good." Fusion of the Worth 4-dot test at distance and near, and presence of stereo acuity of 100 seconds of arc or better were considered "good" binocular function. Multiple logistic regression analysis was used to define factors that correlated with achieving good visual outcome.

RESULTS

Visual acuity was 6/12 or better in 27 (36.5%) eyes. However, good binocular function was achieved in only 11 of these 27 patients. Results of univariate analysis showed that later age at onset of cataract and absence of strabismus were significant for good visual acuity and binocular function. The presence of strabismus increases the risk of not achieving good visual acuity by 5.45-fold.

CONCLUSIONS

Good visual acuity and binocular function can be achieved after removal of monocular cataracts in visually immature children. Patients with strabismus at presentation or during the follow-up period have the least chance of achieving a good sensory result.

Secondary posterior chamber intraocular lens implantation in children

BACKGROUND

Primary intraocular lens (IOL) implantation after cataract aspiration is a widely accepted means of correcting pediatric aphakia. However, little is available in the literature on secondary IOL implantation in children. We present our experience over the past 6 years.

METHODS

The charts of 57 aphakic children (61 eyes) who underwent secondary posterior chamber IOL implantation between January 1989 and April 1996 were reviewed. In general, these children were either intolerant of or noncompliant with their contact lenses. An attempt was made to correlate visual outcome with patient variables. Evaluation of the ciliary sulcus structure was made in selected patients by ultrasonographic biomicroscopy to reveal any changes resulting from the presence of the IOL haptic in the sulcus.

RESULTS

The age range at the time of surgery was 2 to 16 years (mean 8 y). Mean follow-up was 14 months (range 6 to 48 months). Forty-two percent of the patients had a best-corrected visual acuity of 20/40 or better and 78% saw better than 20/80. Posterior capsular opacification occurred in 10 eyes, 8 of which required neodymium:yttrium-aluminum-garnet laser capsulotomy. No major complications occurred. Ciliary sulcus evaluation by biomicroscopy did not reveal any significant ciliary body or scleral erosion. No changes were noted when the implanted sulcus was compared with the normal contralateral side.

CONCLUSION

Although follow-up was short, this review suggests that secondary posterior chamber IOL implantation is a safe alternative when other methods of correcting pediatric aphakia fail.

Pediatric intraocular lens implantation. Surgical results and complications in more than 300 patients

OBJECTIVE

The study aimed to review pediatric intraocular lens (IOL) implantations performed in the authors' institution for the past 7 years.

STUDY DESIGN

The study design was a retrospective chart review.

PARTICIPANTS

All children who underwent IOL placement between January 1, 1989, and January 31, 1996, at ages 2 to 16 years were studied. Follow-up was a minimum of 6 months up to 4 years with an average of 13 months.

INTERVENTION

Placement of a primary or secondary posterior chamber IOL was performed.

MAIN OUTCOME MEASURES

Visual acuity and possible complications were tabulated.

RESULTS

Fifty-seven percent of the cataracts were caused by trauma, and 37% were infantile cataracts. Visual acuities of 20/40 or better were attained in 44% of eyes and visual acuities of 20/50 to 20/80 were attained in 27% of eyes. Visual acuities were better in children older than 4 years of age (P = 0.001). Compliance with amblyopia therapy improved vision (P = 0.004). Fibrinous membranes occurred in 41 eyes (13%), and posterior capsule opacification occurred in 120 eyes (39%). There were no significant differences in visual outcome and complications between primary and secondary implants (17%) or between capsular bag and sulcus fixation (27%). The first stable postoperative refraction was predicted accurately in most patients, based on the Sanders-Retzlaff-Kraff II (SRK II) formula and intraoperative corneal curvature and axial length determinations. The mean refraction differed from the goal by only +0.28 diopter and 84% were within +/- 2 diopters. A few patients showed large overcorrections or undercorrections. On average, no myopic shift occurred.

CONCLUSIONS

Short-term results of IOLs implanted in children older than 2 years of age were favorable. Visual acuities obtained were better than 20/80 in 71% despite a high prevalence (28%) of penetrating trauma. Major complications were rare.

Secondary intraocular lens implantation after cataract surgery in children

PURPOSE

To report results of secondary intraocular lens implantation after cataract surgery in children.

METHODS

We reviewed clinical records for a 5-year period of patients who had cataract surgery in childhood and received a secondary intraocular lens implant. We studied indications for secondary intraocular lens placement; surgical procedures for intraocular lens implantation; preoperative and postoperative visual acuity, refractive error, and binocular status; and complications of the procedure.

RESULTS

A secondary intraocular lens was placed in 28 eyes of 25 patients who had cataract surgery in childhood. In 20 eyes, the lenses were placed in the ciliary sulcus. The other eight eyes had insufficient capsular support for an intraocular lens; in two, the intraocular lens was placed in the anterior chamber and, in six, in the posterior chamber with suture fixation to the sclera. Twenty of 28 eyes (71%) had measurable improvement in visual acuity; only one eye had a decrease in visual acuity of 2 lines. Fifteen patients (54%) had a final refraction within 1.50 diopters of the fellow eye; 21 (75%) were within 3.00 diopters. During follow-up, two eyes developed glaucoma. One had transient pressure elevation; one required two filtration procedures. Three patients required Nd:YAG capsulotomy. Six patients demonstrated Worth fusion at distance and near; three demonstrated 200 seconds of arc or better stereo visual acuity.

CONCLUSION

Secondary placement of an intraocular lens in the posterior chamber appears to be a safe, effective alternative for correction of aphakia in the contact lens- or spectacles-intolerant child or young adult.

Secondary posterior chamber intraocular lens implantation in pediatric patients

PURPOSE

To report results of secondary posterior chamber intraocular lens (IOL) implantation in previously aphakic pediatric patients.

METHODS

In 19 pediatric patients, 19 aphakic eyes (11 after infantile and eight after traumatic cataract surgery) received secondary sulcus-fixated posterior chamber IOL implants.

RESULTS

Visual acuity of 20/40 or better was achieved with IOL implantation and overrefraction in three of 11 infantile (27%) and six of eight traumatic cataract patients (mean follow-ups, 18.1 months [range, 8 to 29 months] and 18.0 months [range, 6 to 28 months]), respectively. Eighteen of 19 patients (95%) demonstrated postoperative vision equal to or better than preoperative levels; 15 of 19 patients (79%) showed improved vision after IOL implantation. The mean +/- SD difference between actual and predicted postoperative refraction at 1 month was -0.97 +/- 0.96 diopter. Average refractive error at last examination was -0.40 +/- 2.43 diopters. Amblyopia therapy was performed in 14 patients. One IOL required repositioning 8 months postoperatively. Strabismus was present in 14 patients before and 13 patients after IOL implantation, requiring surgery in four patients.

CONCLUSIONS

Secondary IOL implantation can be performed successfully in carefully selected pediatric patients. Visual acuity results are better in eyes with a history of traumatic cataract and are influenced by patient compliance. The short-term risks of the procedure appear no greater than those of primary IOL implantation, and complications resemble those seen in adults.

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.

Results following secondary intraocular lens implantation in children

BACKGROUND

Placement of a secondary intraocular lens (IOL) in a child may be considered in children with congenital monocular cataracts who have had complete opacities removed early in life and who later become contact lens intolerant, in eyes that have received trauma which precluded placement of a primary IOL, and in young adults who have bilateral aphakia who become resistant to use of contact lenses or spectacles.

METHODS

Clinical records of all children in our practice who received a secondary IOL between January 1988 and December 1994 were reviewed. Indications, biometry, type of procedures, preoperative and postoperative acuity, refractive error, binocular status, and complications were studied.

RESULTS

During the 7-year period, 242 cataract operations were performed. Fifty-nine eyes received a lens implant, and 28 of these were secondary implants. There was a mean interval between the initial cataract operation and the procedure for the secondary implant of 77 months. The mean follow-up was 35 months (range, 3 to 71) for the 28 eyes that received a secondary implant. Two received anterior chamber implants. Eight eyes had insufficient capsular support for an IOL. Six implants were placed in the posterior chamber and required suture fixation to the sclera. Twenty of 28 eyes had a measurable improvement in visual acuity. Only 1 eye had a decrease in visual acuity of 2 lines. Fifteen patients (54%) had a final refraction within 1.50 diopters of the fellow eye, and 75% were within 3.00 diopters. During the follow-up period, 2 eyes developed glaucoma. One had a transient pressure elevation, and the second has required 2 filtration procedures. Three patients required a Nd: YAG capsulotomy. Six patients demonstrated Worth fusion at distance and near, but only 3 patients demonstrated 200 seconds of arc or better stereo acuity.

CONCLUSION

Placement of contemporary-style, secondary intraocular lenses in children and young adults appears to provide a safe and effective alternative for correction of aphakia in children who become contact lens or spectacle-intolerant.