Lamellar Refractive Surgery Research Articles

Comparison of intraocular pressure measured by ocular response analyzer and Goldmann applanation tonometer after corneal refractive surgery: a systematic review and meta-analysis

BackgroundAccurate measurement of intraocular pressure (IOP) after corneal refractive surgery is of great significance to clinic, and comparisons among various IOP measuring instruments are not rare, but there is a lack of unified analysis. Although Goldmann Applanation Tonometer (GAT) is currently the internationally recognized gold standard for IOP measurement, its results are severely affected by central corneal thickness (CCT). Ocular Response Analyzer (ORA) takes certain biomechanical properties of cornea into account and is supposed to be less dependent of CCT. In this study, we conducted the meta-analysis to systematically assess the differences and similarities of IOP values measured by ORA and GAT in patients after corneal refractive surgery from the perspective of evidence-based medicine.MethodsThe authors searched electronic databases (MEDLINE, EMBASE, Web of science, Cochrane library and Chinese electronic databases of CNKI and Wanfang) from Jan. 2005 to Jan. 2019, studies describing IOP comparisons measured by GAT and ORA after corneal refractive surgery were included. Quality assessment, subgroup analysis, meta-regression analysis and publication bias analysis were applied in succession.ResultsAmong the 273 literatures initially retrieved, 8 literatures (13 groups of data) with a total of 724 eyes were included in the meta-analysis, and all of which were English literatures. In the pooled analysis, the weighted mean difference (WMD) between IOPcc and IOPGAT was 2.67 mmHg (95% CI: 2.20~3.14 mmHg, p < 0.0001), the WMD between IOPg and IOPGAT was − 0.27 mmHg (95% CI: − 0.70~0.16 mmHg, p = 0.2174). In the subgroup analysis of postoperative IOPcc and IOPGAT, the heterogeneity among the data on surgical procedure was zero, while the heterogeneity of other subgroups was still more than 50%. The comparison of the mean difference of pre- and post-operative IOP (∆IOP) was: mean-∆IOPg > mean-∆IOPGAT > mean-∆IOPcc.ConclusionsIOPcc, which is less dependent on CCT, may be more close to the true IOP after corneal refractive surgery compared with IOPg and IOPGAT, and the recovery of IOPcc after corneal surface refractive surgery may be more stable than that after lamellar refractive surgery.

Complications of corneal lamellar refractive surgery

Techniques available for corneal lamellar refractive surgery are laser-assisted in situ keratomileusis (LASIK) using a microkeratome or femtosecond laser incision followed by excimer laser corneal ablation, and femtosecond laser-assisted refractive lenticule extraction (ReLEx). These treatments are nowadays considered to be safe and effective standard procedures for surgical correction of mild to moderate ametropia. Possible complications include too small or decentered optical zones, intraoperative flap cutting errors and postoperative inflammation (e.g. diffuse lamellar keratitis, DLK), epithelial or flap folds, epithelial ingrowths or iatrogenic ectasia. The occurrence of complications may be significantly reduced by compliance to corresponding standards of indication and treatment that are based on current scientific knowledge.

Corneal Ectasia After Intrastromal Presbyopic Surgery

To report histopathologic findings in a case of bilateral corneal ectasia following intrastromal femtosecond laser presbyopia surgery. Case report. A 56-year-old patient was referred for bilateral corneal ectasia. He was treated for hyperopia using LASIK twice in both eyes. A bilateral femtosecond laser intrastromal presbyopia correction was secondarily performed. The patient complained of progressive loss of distance visual acuity shortly after. Corneal topography showed a bilateral central corneal protrusion. Rigid contact lenses were successfully fitted on the right eye and, because the patient still complained, a deep anterior lamellar keratoplasty was performed in the left eye. Light and electronic microscopy of the corneal button revealed that the inner intrastromal incision crossed the LASIK interface and led to stromal bed dehiscence. This case illustrates that intrastromal refractive surgery should not be recommended in eyes previously treated by lamellar refractive surgery.

Comparison of different intraocular pressure measurement techniques in normal eyes, post surface and post lamellar refractive surgery

BackgroundThe purpose of this study was to determine the accuracy of intraocular pressure (IOP) measurement after laser in situ keratomileusis (LASIK) or epithelial laser in situ keratomileusis (Epi)-LASIK using Goldmann applanation tonometry, air puff tonometry, ocular response analyzer corneal compensated IOP (ORA IOPcc) and Pentacam corrected IOP.MethodsA prospective comparative clinical study was conducted between February and September 2011 on 30 eyes divided into four groups, i.e. 20 corneas of 10 patients before LASIK (group A), 20 corneas of the same patients 2 months postoperatively (group B), 10 corneas of five patients before Epi-LASIK (group C), and 10 corneas of the same patients 2 months postoperatively (group D). Patient age ranged from 20 to 50 years. IOP was measured using Goldmann applanation and air puff tonometry, ORA corneal compensation, and Pentacam correction (which also measured central corneal thickness).ResultsSignificant positive linear correlations were found between IOP values measured by Goldmann applanation tonometry and other techniques, and with preoperative pachymetry in group A. The correlation between preoperative Pentacam-corrected and preoperative ORA corneal-compensated IOP was strongest for Goldmann applanation tonometry (r = 0.97 and r = 0.858 respectively, P < 0.001). Compared with preoperative values, postoperative IOP measured by the four methods were significantly lower. The difference was statistically significant when IOP was measured using Goldmann applanation and air puff tonometry compared with the ORA and Pentacam methods (P < 0.001 for LASIK patients and P = 0.017 for Epi-LASIK patients). Nonsignificant correlations were found between the degree of lowering of postoperative IOP and postoperative pachymetry in groups B and D.ConclusionRefractive surgery causes significant lowering of IOP as measured using Goldmann applanation tonometry, air puff tonometry, ORA compensation, and Pentacam correction. LASIK has a greater effect than Epi-LASIK on IOP measurement error following refractive surgery.

New developments in corneal and external disease--LASIK.

Lamellar refractive surgery has evolved into LASIK, which is a widely performed, versatile procedure with a high patient acceptance. In this chapter, the two main components of LASIK were discussed: flap creation and stromal ablation. In each of these areas, the authors explored current technology and new advances, including the femtosecond laser and wavefront-guided ablations. Expanded indications and therapeutic application of LASIK also have come to the forefront. The treatment of anisomyopic amblyopia in the pediatric population is a prime example and was discussed fully in this chapter. The field of refractive surgery has never been stagnant. Surgeons and scientists continue to explore new modalities to increase safety, to improve results, and to broaden applications that benefit the patient population.

Complexity of contact lens fitting after refractive surgery

PURPOSE: To quantify and describe the complexity of contact lens correction on corneas altered by refractive surgery. DESIGN: A case-control study involving postrefractive surgery patients and controls from one multidisciplinary contact lens practice. METHODS: The contact lens care of one randomly selected eye of 30 postrefractive surgery patients (15 postincisional and 15 postlamellar refractive surgery cases) was retrospectively analyzed and compared with that of 30 age-and-gender matched nonrefractive surgery controls. We quantified the complexity by the number of diagnostic lenses used to establish the initial lens order, the number of ordered lenses required to complete the fit, and the number of office visits during the first 4 months of lens care. Final contact lens optical powers, corrected visual acuities, complications, and lens success/failure were also studied. The nonparametric Mann-Whitney U test was used for statistical analysis. RESULTS: Postrefractive surgery eyes utilized statistically more diagnostic lenses ( P = .048), ordered lenses ( P = .008), and office visits ( P < .0001). There were no statistical differences in the number of office visits, number of diagnostic contact lenses used, and number of ordered contact lenses between the postincisional and postlamellar refractive surgery patients. Although final contact lens optical powers were not significantly different ( P = .06) between the two groups, contact lens corrected LogMAR acuities were statistically worse ( P = .013) in the postrefractive surgery eyes than in the control group. Contact lens failures occurred in four postrefractive surgery eyes, while no eyes in the control group failed to tolerate contact lenses. CONCLUSIONS: Corneas altered by either incisional or lamellar refractive surgery techniques are more challenging to fit with contact lenses than nonsurgically altered eyes, requiring more lenses and chair time, while resulting in slightly poorer contact lens corrected visions and more failures.

FLAP COMPLICATIONS ASSOCIATED WITH LAMELLAR REFRACTIVE SURGERY

Abstract PURPOSE: Corneal lamellar refractive surgery for myopia reduces the risk of corneal haze but adds to the risk of flap complications. We retrospectively determined the incidence of flap complications in the initial series of eyes undergoing lamellar refractive surgery by one surgeon. We assessed the incidence of flap complications overall, the trend in these complications during the surgeon's learning curve, and the impact of the complications on best spectacle-corrected visual acuity. METHODS: Charts of the first 1,019 eyes that underwent myopic keratomileusis in situ or laser in situ keratomileusis were reviewed for flap complications and visual outcome. RESULTS: Of the 1,019 eyes, 490 eyes underwent myopic keratomileusis in situ, and 529 eyes underwent laser in situ keratomileusis. Eighty-eight (8.6%) of 1,019 eyes had flap-related complications. Six eyes had two complications. Intraoperative complications included irregular keratectomy in nine eyes (0.9%), incomplete keratectomy in three eyes (0.3%), and a free cap in 10 eyes (1.0%). The incidence of intraoperative complications was six (6.0%) in the first 100 consecutive eyes, 14 (2.3%) in the next 600 consecutive eyes ( P = .04, chi-square test), and one (0.3%) in the last 300 eyes ( P = .03, chi-square test). Postoperative complications included displaced flaps that required repositioning in 20 eyes (2.0%), folds in the flap that required repositioning in 11 eyes (1.1%), diffuse lamellar keratitis in 18 eyes (1.8%), infectious keratitis in one eye (0.1%), and epithelial ingrowth that required removal in 22 eyes (2.2%). The incidence of flap displacement and folds in 200 eyes in which we irrigated under the flap and allowed it to settle without further manipulation averaged 8.5%, whereas the incidence in other groups of 100 consecutive eyes averaged 0.8% ( P P = .0003, chi-square test). No eye lost 2 or more lines of best spectacle-corrected visual acuity because of flap complications. CONCLUSION: Flap complications after lamellar refractive surgery are relatively common but rarely lead to a permanent decrease in visual acuity. Physician experience with the microkeratome and with the handling of the corneal flap decreases the incidence of flap complications.

Discussion by Robert K. Maloney, MD

Bilateral simultaneous refractive surgery remains controversial. Opponents argue that a catastrophic complication could occur bilaterally if simultaneous surgery is performed. With sequential surgery, the outcome in the first eye can be assessed; if a catastrophic complication occurs, the surgeon may then choose not to operate on the second eye. Proponents argue that catastrophic unilateral complications of refractive surgery are very rare, 1 Lin R.T. Maloney R.K. Flap complications of lamellar refractive surgery. Am J Ophthalmol. 1999; 127: 129-136 Abstract Full Text Full Text PDF PubMed Scopus (256) Google Scholar so bilateral catastrophic complications are sufficiently rare that the risk is acceptable. Although mild or treatable complications are relatively common, 1 Lin R.T. Maloney R.K. Flap complications of lamellar refractive surgery. Am J Ophthalmol. 1999; 127: 129-136 Abstract Full Text Full Text PDF PubMed Scopus (256) Google Scholar such a complication on the first eye would not lead a surgeon performing sequential surgery to decide not to operate on the second eye.

Fitting contact lenses after myopic keratomileusis

Purpose: To evaluate the long-term efficacy and results of contact lens fittingfollowing myopic keratomileusis (MKM). Setting: Department of Ophthalmology, Manhattan Eye, Ear, and Throat Hospital, and Swinger Vision Center, New York, New York, USA. Methods: Postoperative fitting of contact lenses was studied as part of a prospectiveevaluation of myopic keratomileusis. In this series, 27 eyes of 20 patients had residual postoperative refractive errors that were corrected with contact lenses. Patients were fit at a mean of 9.4 months after surgery by the trial-lens method. Preoperative keratometry readings and refractions, as well as postoperative keratometry readings, refractions, and contact lens specifications, were recorded and used for fitting. Results: Twenty-six eyes (96%) were fit successfully: 24 (89%) with rigid gas-permeablelenses and 2 (7%) with daily-wear soft lenses. The mean diameter of the rigid lenses was 10.00 mm (range 9.4 to 11.0 mm) and the mean base curve, 8.52 mm (range 7.9 to 9.2 mm). The 2 soft lenses had base curves of 8.6 and 8.9 mm. The mean lens power was −5.24 diopters (D) (range −0.37 to −14.75 D), which was, on average, 4.06 D more myopic than the postoperative spectacle refraction. Postoperative keratometry provided a good starting point for the trial lens. Lenses were tolerated for up to 16 years. One eye, fit with a soft lens, developed significant myopia during the fifth year. Conclusion: After lamellar refractive surgery, the topography of the cornea is significantly altered. Although the postoperative keratometry readings are steeper than the actual curvature, they are reasonably reliable for determining the base curve of the initial trial lens, validating the use of conventional methods of fitting rigid contact lenses in patients who have had MKM.

Very high-frequency ultrasound corneal analysis identifies anatomic correlates of optical complications of lamellar refractive surgery: Anatomic diagnosis in lamellar surgery1,2

ObjectiveTo examine the utility of very high-frequency (VHF) ultrasound scanning in determining the anatomic changes and correlates of optical complications in lamellar refractive surgery. Study DesignCase series. ParticipantsCases analyzed included marked asymmetric astigmatism postautomated lamellar keratoplasty (ALK), image ghosting despite normal videokeratography post-ALK, uncomplicated myopic laser in situ keratomileusis (LASIK), and hyperopic LASIK with regression. MethodsA prototype VHF ultrasound scanner (50 MHz) was used to obtain sequences of parallel B-scans of the cornea. Digital signal processing techniques were used to measure epithelial, stromal, and flap thickness values in a grid encompassing the central 4 to 5 mm of the cornea, enabling pachymetric mapping of each layer with 2-micron precision. Main outcome measureThe appearance of the corneas in VHF ultrasound images and thickness values of individual corneal layers determined from VHF ultrasound data. ResultsVHF ultrasound resolved the epithelial, stromal cap, or flap and residual stromal layers 1 year after lamellar surgery. Asymmetric stromal tissue removal was differentiated from stromal cap irregularity. Epithelium acted to compensate for asymmetry of the stromal surface about the visual axis and for localized surface irregularities. Irregularities in the epithelial-stromal interface accounted for image ghosting present despite apparently normal videokeratography. Epithelial thickening was shown after uncomplicated myopic LASIK. Hyperopic LASIK demonstrated relative epithelial thickening localized to the region of ablation accounting for refractive regression. ConclusionsVHF ultrasound shows promise as a sensitive method of determining the anatomic correlates of optical complications in lamellar refractive surgery.

Flap complications associated with lamellar refractive surgery

PURPOSE: Corneal lamellar refractive surgery for myopia reduces the risk of corneal haze but adds to the risk of flap complications. We retrospectively determined the incidence of flap complications in the initial series of eyes undergoing lamellar refractive surgery by one surgeon. We assessed the incidence of flap complications overall, the trend in these complications during the surgeon’s learning curve, and the impact of the complications on best spectacle-corrected visual acuity.METHODS: Charts of the first 1,019 eyes that underwent myopic keratomileusis in situ or laser in situ keratomileusis were reviewed for flap complications and visual outcome.RESULTS: Of the 1,019 eyes, 490 eyes underwent myopic keratomileusis in situ, and 529 eyes underwent laser in situ keratomileusis. Eighty-eight (8.6%) of 1,019 eyes had flap-related complications. Six eyes had two complications. Intraoperative complications included irregular keratectomy in nine eyes (0.9%), incomplete keratectomy in three eyes (0.3%), and a free cap in 10 eyes (1.0%). The incidence of intraoperative complications was six (6.0%) in the first 100 consecutive eyes, 14 (2.3%) in the next 600 consecutive eyes (P= .04, chi-square test), and one (0.3%) in the last 300 eyes (P = .03, chi-square test). Postoperative complications included displaced flaps that required repositioning in 20 eyes (2.0%), folds in the flap that required repositioning in 11 eyes (1.1%), diffuse lamellar keratitis in 18 eyes (1.8%), infectious keratitis in one eye (0.1%), and epithelial ingrowth that required removal in 22 eyes (2.2%). The incidence of flap displacement and folds in 200 eyes in which we irrigated under the flap and allowed it to settle without further manipulation averaged 8.5%, whereas the incidence in other groups of 100 consecutive eyes averaged 0.8% (P < .00001, chi-square test). The incidence of diffuse lamellar keratitis was 0.2% in eyes that had undergone myopic keratomileusis in situ and 3.2% in eyes treated by laser in situ keratomileusis (P = .0003, chi-square test). No eye lost 2 or more lines of best spectacle-corrected visual acuity because of flap complications.CONCLUSION: Flap complications after lamellar refractive surgery are relatively common but rarely lead to a permanent decrease in visual acuity. Physician experience with the microkeratome and with the handling of the corneal flap decreases the incidence of flap complications.

Lamellar refractive surgery with scanned intrastromal picosecond and femtosecond laser pulses in animal eyes.

To evaluate the use of scanned intrastromal picosecond and femtosecond laser pulses in lamellar refractive surgical procedures. Intrastromal corneal photodisruption was performed in fresh porcine and primate cadaver eyes with a solid-state femtosecond laser. Laser pulses were focused 150 to 200 microns below the epithelial surface and scanned in a spiral pattern to create a plane. A flap was made by scanning an arc pattern from the plane of the spiral to the surface of the cornea. Tissue plane separation was graded using a standard scale, while internal surfaces were analyzed by scanning electron microscopy. Comparison was made to a picosecond laser system using the same delivery system device. Creation of a stromal lenticule for in situ keratomileusis was also demonstrated and compared with both laser systems. For femtosecond pulses, tissue separation was achieved best with pulse energies from 4 to 8 microJ and spot separations from 10-15 microns. Picosecond pulses accomplished less complete separations with pulse energies of 25 microJ and spot separations from 10 to 20 microns. Surface quality corresponded to dissection results, with high-grade dissections resulting in a smooth surface appearance, versus a more irregular surface for low-grade dissections. Although high-grade dissections could be created with picosecond pulses (with optimal parameters) in ex vivo porcine eyes, only femtosecond parameters produced similar results in ex vivo primate eyes. In contrast to previous attempts using picosecond lasers which require additional mechanical dissection, high precision lamellar refractive surgery may be practical with femtosecond laser pulses.

Diffuse lamellar keratitis: A new syndrome in lamellar refractive surgery

Objective This study aimed to describe a syndrome that the authors call diffuse lamellar keratitis that follows laser in situ keratomileusis (LASIK) and related lamellar corneal surgery. Design Noncomparative case series and record review. Participants Thirteen eyes of 12 patients in whom infiltrates developed in the interface after lamellar refractive surgery were studied. Intervention Topical antibiotics or corticosteroids or both were administered. Main outcome measures Corneal infiltrate appearance, focality, location, and clinical course were measured. Results Patients presented between 2 and 6 days after surgery with pain, photophobia, redness, or tearing. Ten cases directly followed either myopic keratomileusis or LASIK. Three cases followed enhancement surgery without the use of a microkeratome. All 13 cases had infiltrates that were diffuse, multifocal, and confined to the flap interface with no posterior or anterior extension. The overlying epithelium was intact in each case. Cultures were negative in the two cases cultured. Ten eyes were treated with antibacterial agents; two eyes had fluorometholone four times daily added to the routine postoperative antibacterial regimen, and one eye had the antibacterial agent discontinued and was treated with topical fluorometholone alone. All infiltrates resolved without sequelae. Conclusions A distinct syndrome of unknown cause of noninfectious diffuse infiltrates in the lamellar interface is described. It can be distinguished from infectious infiltrates by clinical presentation and close follow-up. Patients with the syndrome should be spared the more invasive treatment of infectious keratitis.

New instrument for revision lamellar refractive surgery

A new instrument that aids in retreating or revising lamellar refractive surgery is described. The edge delineator and lifter can both delineate and lift the edge of a previously made corneal flap.

Excimer Laser in Situ Keratomileusis

Excimer laser in situ keratomileusis (LASIK) is the most recent evolution of the family of lamellar refractive surgery, which includes keratophakia, freeze myopic keratomileusis, epikeratoplasty, keratomileusis in situ, and Buratto-style excimer laser keratomileusis. LASIK is the marriage of the microkeratome, with its ability to resect a piano lamellar disc of corneal tissue, and the precision of the argon-fluoride excimer laser, operating at 193 nm to remove submicron layers of corneal stroma to achieve a highly predictable refractive result. Myopia, astigmatism, hyperopia, presbyopia, and complex ablations for abnormal topography have been attempted. Although LASIK as a technique is relatively young, the early results are very encouraging. Investigators worldwide are vigorously investigating its efficacy, predictability, stability, and safety.

Accuracy of Corneal Lenticules Produced for Lamellar Refractive Corneal Surgery

The layer thickness of the corneal lenticules separated with the Berlin microkeratome and shaped by keratomileusis, keratophakia, keratokyphosis, and intrastromal excimer-laserkeratomileusis was measured with the Universal Measuring Microscope. The vertices of most corneal lenticules showed an undercorrection of the measured values compared with the calculated ones. In keratomileusis, the vertex of the central part of the optical zone of 3.6 mm attained 79 +/- 19 microns instead of 80 microns (99%); in keratophakia, 74 +/- 19 microns instead of 80 microns (93%); in myopic keratokyphosis, 77 +/- 11 microns instead of 105 microns (74%); in hyperopic keratokyphosis, 72 +/- 28 microns instead of 105 microns (69%); and in excimer-laserkeratomileusis, 52 +/- 12 microns instead of 39 microns (120%). The undercorrection of myopic and hyperopic keratokyphosis indicate that this type of nonfreeze keratomileusis is not capable to cut a tissue lens of predicted refraction from compressed corneal tissue. Near symmetrical profiles were achieved in all types of refractive corneal surgery but excimer-laserkeratomileusis had the smallest standard deviation. It was significantly smaller than in hyperopic keratokyphosis (p < 0.05). Intrastromal excimer-laserkeratomileusis of tightly fixed corneal lenticule in the Berlin microkeratome might be the most predictable method of lamellar refractive corneal surgery.

An Independent Evaluation of Second Generation Suction Microkeratomes

Microkeratome designs for lamellar refractive surgery have changed significantly in recent years. Three microkeratome systems (Automatic Corneal Shaper (Steinway Instrument Company, Inc, San Diego, Calif), Draeger Lamellar Keratome (Storz Instrument GmbH, Heidelberg, Germany), and Microprecision test model (Microprecision Instrument Company, Inc, Phoenix, Ariz) were subjected to a concurrent and independent evaluation. Three types of keratectomies (primary superficial stromal, secondary intrastromal, and primary deep stromal) were performed under identical conditions in human cadaver eyes. The resected discs and the beds were observed for uniformity, accuracy, centering, and smoothness. Scanning electron microscopy of the corneal beds and cutting blades was done. The three systems produced irregular surfaces with chatter lines that appeared least rough with the Draeger rotating machine. The average primary and secondary section diameters were undersized by 10% in all three systems. The average primary keratectomy thickness was more accurate with Steinway, but the variability was over 20 microns in all three systems. Regarding the average secondary keratectomy thickness, Steinway tended to cut thicker, whereas Draeger and Microprecision tended to cut thinner than attempted. The Draeger blade presented the smoothest edge. All three systems need substantial improvements to produce more accurate, reproducible, and smooth resections. More reliable methods to accurately measure the thickness of the resected cornea should be developed.

Lamellar Refractive Surgery: Where Have We Been and Where Are We Going?

Lamellar Refractive Surgery: Where Have We Been and Where Are We Going?

Pathology of Corneal Hydrogel Alloplastic Implants

Hydrogel keratophakia is a new form of lamellar refractive surgery which, in theory, can deal with almost all forms of refractive error. We examined the histopathological effects of several types of hydrogel materials on the cornea of non-human primates. With the exception of one type of hydrogel material, which was associated with endothelial cell degeneration, only minor histopathologic changes were seen up to a maximum of one year of observation, including thinning of the epithelium and decreased population of stromal keratocytes. These changes did not correlate with any clinical abnormalities. Additional extensive preclinical testing and eventual human clinical trials will determine the safety and efficacy of this procedure.

REFRACTIVE CORNEAL SURGERY: THE USE OF IMPLANTABLE ALLOPLASTIC LENS MATERIAL

A basic problem encountered in all forms of lamellar refractive surgery has been the predictability of the optical corrections. Corneal tissue used in refractive surgery behaves in a variable fashion because its shape is determined in vivo by the process of healing and graft repopulation. Therefore no preoperative measure of the ultimate power of the lathed corneal lens can be made. Another drawback is the limited supply of donor corneal tissue. In an effort to overcome these problems, we have used alloplastic materials in conjunction with lamellar refractive surgery to improve the predictability of the result. The use of this material would also allow accurate preoperative determination of lens power. Intralamellar implants appeared to heal quite rapidly after surgery. Their optical clarity was excellent and the corneal surface appeared stable. Further research into long-term stability and predictability are currently underway.