Nonpreserved human amniotic membrane transplantation for conjunctival reconstruction after excision of extensive ocular surface neoplasia.

PURPOSE: To report our experience on the use of nonpreserved human amniotic membrane transplantation (AMT) in ocular surface reconstruction after excision of extensive ocular surface neoplasia (OSN). DESIGN: Prospective noncomparative interventional case series. PARTICIPANTS: In all, 10 eyes of 10 consecutive patients with extensive OSN involving various areas of limbus, conjunctiva, and cornea (conjunctival carcinoma in situ, four eyes; squamous cell carcinoma, three eyes; malignant melanoma, two eyes; conjunctival-orbital lymphangioma, one eye) were included in this prospective noncomparative interventional case series. After excision of the neoplasia with 3-4 mm tumour-free margins, double freeze-thaw cryotherapy was applied to the margins of the remaining conjunctiva, and nonpreserved human amniotic membrane graft was sutured to the adjacent conjunctiva using 8/0 vicryl sutures and cornea using 10/0 nylon sutures, with the epithelial side facing up to cover the bare sclera and cornea. Postoperatively, topical corticosteroids were used for 3 months. RESULTS: After tumour excision and AMT, a satisfactory result with a wet, stable conjunctiva, and rapid and complete healing was observed in all eyes. Over a mean follow-up of 10.0 months (range, 6-27 months), all but one eye remained free of tumour recurrence. In one eye with conjunctival melanoma, there was a small recurrence, which was treated with excision and cryotherapy. Treatment complications were partial stem cell deficiency in two eyes and symblepharon formation in one eye. Immune graft rejection was not encountered. CONCLUSION: Nonpreserved human AMT appears to be useful for reconstruction of ocular surface following excision of extensive OSN.

Long-term follow-up of corneal graft survival following bone marrow transplantation in the Maroteaux-Lamy syndrome.

PURPOSE: To present a case of Maroteaux-Lamy syndrome (MLS, mucopolysaccharidosis [MPS] type VI) who underwent bone marrow transplantation (BMT) for gene transfer at the age of 13, and penetrating keratoplasty at the age of 17, and maintained clear corneal grafts bilaterally for 13 years. To our knowledge, this is the longest follow-up reported on corneal graft survival in a patient with MLS and BMT. METHODS: In 1982, BMT was successfully performed on a 13-year-old girl with MLS with growth retardation, typical facial features, skeletal and joint deformities, hepatosplenomegaly, cardiopulmonary dysfunction, and corneal clouding. Corneal transplantation was done on the left eye in 1986, and on the right eye in 1987 (6 months later) without difficulty or complication. RESULTS: Thirteen years postoperatively, the patient was systemically well, and both eyes retained clear corneal grafts. CONCLUSION: BMT retarded further dysfunction from MLS, and the corneal transplants retained clarity. Further controlled studies with longer follow-up are required to establish the efficacy of BMT in ocular manifestations of MPS or MLS.

Intrastomal corneal ring segments: reversibility of refractive effect.

PURPOSE: To evaluate the reversibility of refractive effect following removal of the ICRS (intrastromal corneal ring segments; Intacs). METHODS: Data from 34 eyes from which ICRS were removed during United States FDA Phase II and III clinical trials were evaluated with regard to segment size, loss or change of best spectacle-corrected visual acuity (BSCVA), any change of uncorrected visual acuity (UCVA), manifest spherical equivalent refraction, manifest cylinder refraction, stability of manifest cylinder refraction, and subjective visual symptoms. RESULTS: Out of 725 initial or contralateral eyes placed with the ICRS during Phase II and III clinical trials, segments were removed from 34 eyes (4.7%). Other than one (1/725, 0.1%) safety related ICRS removal, 30/725 (4.1%) were due to visual symptoms. ICRS removal was accomplished under topical anesthesia without complications in all eyes. The mean length of time the segments remained in the cornea after initial surgery was 10.3 +/- 5.4 months. At 3 months after ICRS removal, 21 eyes had monitored data available and were within +/-1 line or 10 letters of their preoperative BSCVA. Twenty eyes (20/21, 95%) returned to within +/-1.00 D of their preoperative manifest spherical equivalent refraction. All eyes had a stable refraction at the 3-month examination after removal, and a manifest spherical equivalent refraction within +/-1.00 D of their 1-month examination after removal. Nineteen eyes (19/21, 90%) returned to within +/-2 lines and 16 eyes (16/21, 76%) returned to within +/-1 line of preoperative UCVA. CONCLUSION: The ICRS (Intacs) was easily and safely removed, and eyes returned to preoperative refractive status within 3 months.

Intraoperative PAR corneal topography system (CTS): comparison of its keratometric readings to manual keratometer, auto-keratometer, EyeSys Corneal Analysis system, and slit lamp PAR CTS in healthy eyes.

PURPOSE: To compare the keratometric readings obtained from Intraoperative PAR Corneal Topography System (IOPAR) to those produced by manual keratometer (Mnl-Km), autokeratometer (Auto-Km), EyeSys CAS (EyeSys Corneal Analysis System) and slit lamp PAR CTS in healthy eyes. METHODS: All instruments were calibrated prior to use and only data from the best image obtained was used for statistical analysis. Simulated keratometry readings obtained from the central 3-mm zone of the corneas by IOPAR, including flat (K1) and steep (K2) keratometry readings, average keratometric power (AK), astigmatism (As) (difference between steep and flat keratometry readings) and the axis of the steep meridian (Ax) were compared to those from four other units. The latter units were also compared among themselves. Statistical analysis was done for right and left eyes separately. For each variable, average differences between the measurements taken from pairs of instruments were estimated, with corresponding 95% confidence intervals. The degree of agreement between pairs of instruments on individual measurements was additionally assessed, via the use of "Bland-Altman"-type plots, and estimates of the proportion of cases achieving satisfactory agreement. Additionally, for every variable, the average of the measurements taken from the different instruments were compared. RESULTS: Forty-five (22 right and 23 left) normal corneas of 26 volunteers were examined. On the average, IOPAR tended to measure K1 higher than slit lamp PAR CTS system. Because K2 measurements taken by the IOPAR were higher than that of all other instruments, the As measurements, on the average, were also higher than that of others, with the exception of the PAR CTS. For the same reasons, the IOPAR produced average AK readings that were higher than those taken by EyeSys CAS and PAR CTS. When the individual measurements taken by the IOPAR were compared with each of the other units, according to the arbitrary designation of satisfactory agreement within +/-0.5 D (for K1, K2, AK, and As) and +/-20 degrees (for Ax), for almost all parameters, proportion of differences that were within the agreement range varied from 0.33 to 0.82, with wide confidence intervals (confidence interval lower limits ranging from 0.20 to 0.61 and upper limits ranging from 0.62 to 0.94). CONCLUSIONS: IOPAR is a clinically useful topographic system, producing qualitative and quantitative data in the operating environment that, in normal corneas, on the average, matches those produced by the other units in the clinic. When individually analyzed, its keratometric measurements may show greater variations with respect to other units. Further studies with multiple examiners, in corneas with high or irregular astigmatism are required to establish its reproducibility and efficacy.

Is intraoperative topography predictive of postoperative topographical changes following refractive surgery?

PURPOSE: To evaluate the usefulness of measuring corneal topography intraoperatively by Intraoperative PAR Corneal Topography System (IOPAR CTS) to predict the postoperative topographical changes in patients undergoing refractive surgery. METHODS: Topographical measurements of 9 eyes of 9 patients were taken by IOPAR CTS: 6 immediately after Intrastromal Corneal Ring Segments (ICRS) placement surgery and 3 immediately after Photorefractive Keratectomy (PRK) surgery. The topographical images taken by IOPAR CTS were analyzed to determine the quality of the image produced and the correlation of the keratometric data from the central 3 mm of cornea with measurements taken from an autokeratometer (Auto-Km) and the EyeSys Corneal Analysis System (CAS) for the same eyes taken three months following the procedure. RESULTS: At the 3-month postoperative exam, the correlation coefficients for flat (K1), steep (K2), and average keratometry (AK) readings produced by the Auto-Km and the EyeSys CAS were quite high. However, the correlation coefficients for K1, K2, AK, As or steep meridian axis (Ax) readings taken intraoperatively by IOPAR CTS were quite low when compared to the readings taken by either the Auto-Km or EyeSys CAS three months postoperatively. CONCLUSION: We found IOPAR CTS, relatively difficult to perform in the operating room during refractive surgical procedures and not useful clinically in predicting the postoperative topographical changes induced by ICRS or PRK procedure. Further studies are required to establish the efficacy and reproducibility of the instrument.

Characteristics of the myopic patient population applying for refractive surgery.

PURPOSE: Assessment of the characteristics of the myopic patient population applying for refractive surgery in order to determine the potential market for myopic refractive surgery. METHODS: Records of consecutive patients who responded to an advertisement for refractive surgery to correct myopia were evaluated retrospectively with regards to patient demographics and the amount and distribution of the refractive error. Data were compared to that available from population-based statistics for distribution of myopia in the general population. For statistical analysis, one sample Student's t-test and two tailed Student's t-test were utilized. RESULTS: Two hundred fifty seven patients (140 women and 117 men) responded to an advertisement for refractive surgery during the six month period between January and June 1998. Mean spherical equivalent (SEQ) of the patient population was -4.59+/-2.54 D (min;-0.25 D, max;-15.75 D) right eye (OD) and -4.62+/-2.82 D (min;-0.25 D, max;-15.25 D) left eye (OS). Among the patients who had myopia with an astigmatism of at most 1.00 D (n=165), the distribution of refractive error was statistically significantly different from that obtained from population-based statistics, such that, although most of the myopic population (40%) had an SEQ of -1.00 to -2.25 D, the majority of our patients (54.8%) who applied for myopic refractive surgery had an SEQ of -2.50 to -5.00 D. Another striking difference was that, although patients with an SEQ more than -6.00 D were a minority(2%) in the population study, in our study group, they comprised 16.7% of the patients seeking refractive correction. The difference between the SEQ of the right and left eyes ranged from 0.00 D to 13.0 D (mean, 0.89+/-1.5 D), 47.1 % having a difference of at most +/-0.5 D between the two eyes. The mean cylindrical error in the patient population was 0.69+/-0.93 D (min: 0, max: -4.5) OD and 0.69+/-0.96 D (min: 0, max: -4.5) OS. There were no statistically significant differences between the distribution of SEQ or cylindrical refractive error between males and females. CONCLUSION: Although a population-based study reported that most of the myopic population (40%) had an SEQ of -1.00 to -2.25 D, the majority of our patients (54.8%) who applied for myopic refractive surgery had an SEQ of -2.50 to -5.00 D. On the other hand, while patients with an SEQ of -6.00 D and more constituted only about 2% of the general population, they accounted for 16.7% of our study population. Therefore, the refractive characteristics of the patient population applying for myopic refractive surgery may not necessarily parallel that of general population-based statistics. In order to establish a more effective refractive surgery practice, it is feasible to perform local studies and reevaluate the requirements of your practice accordingly.

Adjustability of refractive effect for corneal ring segments.

PURPOSE: To evaluate the safety and efficacy of adjustability of the refractive effect of intrastromal corneal ring segments (ICRS, Intacs). METHODS: Data from four patients who had their initial Intacs removed and exchanged for new Intacs of different thickness sizes during a United States Food and Drug Adminstration Phase II clinical trial were evaluated with regard to segment size, reasons for exchange, duration within the cornea before exchange procedure, loss or change of spectacle-corrected visual acuity, change of uncorrected visual acuity, manifest refraction, cycloplegic refraction, topography after exchange, and stability of refraction. RESULTS: The exchange procedure was performed in two patients due to undercorrection and in two for overcorrection. The length of time the segments remained in the cornea after initial surgery varied from 6 to 15 months (mean, 10.25 +/- 4.03 mo). The most recent examination occurred between 4 to 18 months (mean, 10.0 +/- 6.32 mo) following the exchange procedure and showed improved uncorrected visual acuity with a range from 20/16 to 20/20 and a gain of 2 to 7 lines of uncorrected visual acuity compared to baseline. No eyes lost any lines of spectacle-corrected visual acuity following the exchange procedure and all preserved their preoperative spectacle-corrected visual acuity of 20/16. The intended refractive correction was achieved in the first few days of the exchange procedure and remained stable. CONCLUSION: In these four eyes that were over- or undercorrected after initial Intacs placement, segment thickness sizes were exchanged after 6, 8, 12, and 15 months without complication and with final uncorrected visual acuities of 20/16 to 20/20.

Photorefractive keratectomy after intrastromal corneal ring segment explantation.

PURPOSE: To describe a case of photorefractive keratectomy after removal of intrastromal corneal ring segments from the cornea. METHODS: During United States Food and Drug Administration Phase III Trials for intrastromal corneal ring segments (ICRS), the implanted segments were removed from the cornea of the right eye of a patient because of dissatisfaction with glare, halos, and fluctuating vision. Ten months after ICRS explantation, the-patient underwent a photorefractive keratectomy procedure to the same eye. RESULTS: One month after removal of the ICRS, the patient's manifest refraction was within +/- 0.50 diopters of his original manifest refraction. Photorefractive keratectomy was planned to the same eye 6 months later. At the first attempt, the epithelium could not be removed with the laser and scrape technique, and residual epithelium was noted at the vertical meridian (12 o'clock) corneal incision site, which had been used for ICRS surgery and explant; therefore, the procedure was aborted. At the second attempt, with a mechanical epithelial brush (AMOILS Epithelial Scrubber; Innova, Inc, Toronto, Canada), the epithelium was removed with ease. After this, photorefractive keratectomy was done without difficulty or complication. At his most recent 8-month postphotorefractive keratectomy examination, the patient had an uncorrected visual acuity of RE: 20/16, with a manifest refraction of -0.75 to 0.75 x 170 degrees, a faint haze at the site of the stromal channel, and a small scar at the incision site on slit-lamp examination. CONCLUSIONS: Intrastromal corneal ring segments can be readily removed from the cornea, if required. In this case, the refraction returned to its preoperative state soon after the explant procedure and remained stable over time. Photorefractive keratectomy was performed as a secondary refractive surgical procedure after the removal of ICRS without difficulty or complication. However, removal of the epithelium is probably best accomplished with the use of an epithelial brush, considering the changes in the epithelial adherence in a postsurgical cornea. Further studies are required to establish the safety and efficacy of secondary refractive surgical procedures after ICRS explantation.

Bilateral abortive cryptophthalmos associated with oculocutaneous albinism.

PURPOSE: To document a case of bilateral abortive cryptophthalmos associated with oculocutaneous albinism. METHODS: We describe a 13-year-old female patient with blond skin and hair who had anomalous face and eyes first noted at birth. RESULTS: The patient had fair hair and complexion, bilateral anomalous wedge of scalp hair, upper eyebrow and eyelid deformities, cup-shaped ears, broad based nose with depressed bridge and midline groove, iris transillumination and diffuse hypopigmentation and foveal hypoplasia in fundus examination. CONCLUSION: Based on the clinical and laboratory findings, the reported case represents tyrosinase-positive oculocutaneous albinism together with bilateral abortive cryptophthalmos. The oculocutaneous albinism can either be an entirely new criterion to the whole syndrome of cryptophthalmos, or, more probably, the condition can be due to a double affliction which is primarily related with consanguinity of the parents. The importance of ante-natal diagnosis and genetic counseling are emphasized in such cases where the two recessive genes for two different conditions coexist.

Conjunctival impression cytology in patients wearing contact lenses.

PURPOSE: Evaluation of contact lens-induced cytologic changes on the conjunctival surface. METHODS: Fifty eyes of 25 patients wearing soft or rigid gas-permeable contact lenses, and 50 healthy eyes of 25 control subjects were examined with conjunctival impression cytology. Of the patients wearing contact lenses, 40% did not have any contact lens-related complaints, whereas 60% had some minor complaints related to contact lens intolerance. The material obtained by impression cytology was examined with regard to epithelial cell morphology, goblet cell density, and snake-like nuclear chromatin changes. RESULTS: When epithelial cell morphology was graded according to the system described by Nelson, specimens from the control group revealed 90% of the eyes to be grade 0 and 10% to be grade 1, whereas of the eyes wearing contact lenses, 8% were grade 0, 36% grade 1, 32% grade 2, and 24% grade 3. Thus statistically significant differences were observed between the control group and the contact lens group with regard to each grade (p < 0.05) as well as to the goblet cell densities (p < 0.05). Snake-like chromatin changes, on the other hand, were observed in 30 and 27% of the eyes wearing soft and rigid gas-permeable contact lenses, respectively, whereas these were not encountered in any eye in the control group. CONCLUSION: Epithelial changes were noted to be more frequent and more severe in symptomatic patients than in those without any complaints. No correlation was found between average duration of contact lens wear and the risk of contact lens intolerance or development of squamous metaplasia.