Perioperative Corneal Abrasion: Updated Guidelines for Prevention and Management.

Corneal abrasion is the most common ocular complication in surgery. Treatment requires pain control, antimicrobial prophylaxis, and close monitoring. Pain improves significantly after 24 hours and should be resolved by 48 hours. Persistent, worsening, or new symptoms warrant immediate specialist consultation. The authors review the pathophysiology of perioperative corneal abrasion, and propose updated evidence-based guidelines for improved patient care.

The accuracy of the double-K adjustment for third-generation intraocular lens calculation formulas in previous keratorefractive surgery eyes.

PURPOSE: To evaluate the effect of the double-K (DK) modification on third-generation formulas. METHODS: Thirty-eight previously myopic and 24 previously hyperopic eyes that underwent phacoemulsification with intraocular lens (IOL) insertion after Laser in situ keratomileusis (LASIK) were evaluated. Pre-LASIK refraction and keratometry, post-LASIK topography, axial length (AL), IOL type and power, and 1-month postphacoemulsification refraction were recorded spherical equivalent after phacoemulsification (SE(postphaco)). Measured corneal power was adjusted using published and validated methods for postmyopic and posthyperopic LASIK. For each eye, and using SE(postphaco), different DK-IOL formulas were used to calculate the corresponding IOL power, the outcome measure, which was compared with the implanted IOL. RESULTS: DK-Holladay 1 yielded the highest Pearson correlation coefficient (PCC), 0.955 for myopes and 0.943 for high myopes (AL>26 mm). Mean error (ME) and mean absolute error (MAE) for myopes for DK Sanders-Retzlaff-Kraff theoretical formula [DK-SRK/T] were 0.44±0.84 D and 0.75±0.61 D for DK-SRK/T compared with -0.04±0.67 D and 0.52±0.40 D for DK-Holladay 1 (P<0.001 and P=0.016, respectively), and 0.03±0.88 and 0.64±0.58 for DK-Hoffer Q. For high myopes, ME and MAE were 0.75±0.81 D and 0.84±0.69 D for DK-SRK/T, and -0.05±0.74 D (P<0.0001) and 0.57±0.45 D (P=0.019) for DK-Holladay 1. About 29% of DK-SRK/T eyes with large AL had MAE>1.5 D, compared with 0% for DK-Holladay 1 and 14% for DK-Hoffer-Q. Eyes with previous hyperopic LASIK faired similarly for all formulas, with similar PCCs, and only 8% in each category with MAE>1.5 D. CONCLUSIONS: DK-SRK/T overestimates IOL power in eyes with large AL, especially with concomitant steep pre-lasik keratometry. Among third-generation formulas, DK-Holladay 1 seems more accurate to use in postmyopic LASIK eyes.

Sarnicola air-visco bubble technique in deep anterior lamellar keratoplasty.

PURPOSE: The purpose of this study was to describe a new modification for big-bubble deep anterior lamellar keratoplasty (DALK) using pneumatic pressure to detach Descemet membrane (DM) via air injection followed by ophthalmic viscoelastic device (OVD) injection. METHODS: After failure of big-bubble formation after air injection, OVD was injected from a different site other than the previous air injection using a 27-gauge cannula to detach DM, called air-visco bubble (AVB) DALK technique. The technique was used in 7 human corneoscleral rims that were investigated with anterior segment optical coherence tomography and histopathology and in 69 eyes that underwent DALK surgeries. RESULTS: Big-bubble formation was noted in 4 of 7 of the donor corneoscleral rims. The anterior segment optical coherence tomography showed big-bubble formations together with intrastromal OVD accumulation. The histology of the donor corneas showed microdetachments at the DM in the periphery, deep intrastromal separation, and big-bubble formation filled with OVD. One hundred forty-one of 210 eyes (67%) underwent successful DALK with only air injection, and 69 of 210 eyes (33%) underwent AVB technique when a big bubble was not achieved with only air injection. All the corneas showed a clear interface with good wound healing when DM was bared with the AVB DALK technique. CONCLUSIONS: Additional OVD injection to detach DM may be useful in cases where air injection fails. Also, creating small DM detachments with air injection may facilitate the formation of a big bubble with further OVD injection.

Histopathology and spectral domain OCT findings of pneumatic-assisted dissection in DALK.

PURPOSE: To correlate big-bubble deep anterior lamellar keratoplasty findings in donor corneas with anterior segment optical coherence tomography (OCT) and histology. METHODS: This research was conducted entirely at the University of Texas Southwestern Medical Center in Dallas, Texas. We performed deep intrastromal air injections in donor corneas on artificial chambers. Surgical patterns (big bubble, intrastromal emphysema, and perforation) were assessed by spectral domain OCT with a handheld probe and histology. RESULTS: Surgical patterns were evaluated by histology using a novel embedding technique. A classic big bubble may be a Descemet membrane (DM) detachment with a few attached stromal fibrils. There were no large intra-DM separations as previously reported. The emphysematous surgical patterns result from intrastromal emphysema, which can be accompanied by microdetachments of DM. We saw indirect OCT signs of big bubble, but scatter from intrastromal emphysema limits deeper imaging. CONCLUSIONS: Surgical patterns of big bubble and intrastromal emphysema correlate with characteristic histology findings. Marked scatter on OCT by intrastromal emphysema limits visualization of deeper corneal structures, but the presence of a big bubble may be inferred.

Comparative study of descemet stripping automated endothelial keratoplasty donor preparation by Moria CBm microkeratome, horizon microkeratome, and Intralase FS60.

PURPOSE: To evaluate the quality of stromal bed and the safety on endothelium in preparation of donor tissue for Descemet stripping automated endothelial keratoplasty in a masked fashion using 2 mechanical microkeratomes and a femtosecond laser. METHODS: Deep anterior lamellar dissection was performed on 15 donor corneas. Central endothelial cell density was calculated using specular microscopy before and after the dissection. One cornea from each of 5 donor pairs was cut with the Moria ALTK system with the CBm microkeratome using the 300-µm head and the mate cut with the Horizon disposable 300-µm microkeratome. Five additional donor corneas were cut with the Intralase 60-kHz FS laser. The donor corneas were then bisected with half of the cornea used for Live/Dead assay to study central endothelial viability. The other halves were sent for scanning electron microscopy of the stromal bed. Qualitative surface roughness of the scanning electron microscopy images was graded by 2 masked observers, and quantitative surface roughness was assessed using roughness evaluation software. RESULTS: The Horizon group showed a smoother stromal bed compared with the Moria or Intralase groups by 2 masked observers. However, the Moria group had the smoothest quantitative score of all the groups when assessed by roughness evaluation software. There was no statistically significant difference among the 3 groups in the percentage change in the central endothelial cell density or percentage of viable central endothelium by Live/Dead assay after the dissection. CONCLUSIONS: Both mechanical microkeratomes created smoother stromal bed dissections than the femtosecond laser. All systems provided good endothelial cell viability.

Apodized diffractive intraocular lens implantation after laser in situ keratomileusis with or without subsequent excimer laser enhancement.

PURPOSE: To evaluate the long-term refractive and visual outcomes of apodized diffractive multifocal intraocular lens (IOL) implantation after myopic laser in situ keratomileusis (LASIK) with or without subsequent excimer laser enhancement. SETTING: University of Texas Southwestern Medical Center at Dallas, Texas, USA. DESIGN: Comparative case series. METHODS: This study comprised consecutive patients who had implantation of an AcrySof ReSTOR multifocal IOL after previous LASIK. Included were eyes that had refractive surgery enhancement with a Visx Star S4 excimer laser for residual refractive error correction and eyes that had neodymium:YAG (Nd:YAG) capsulotomy. RESULTS: Of the 49 eyes (38 patients), 21 (42.9%) had laser enhancement and 25 (51.0%) had an Nd:YAG capsulotomy. The mean follow-up was 14.2 months ± 7.23 (SD) (range 9 to 29 months). Although the uncorrected distance visual acuity (UDVA) was significantly worse in eyes with enhancement than in those with no enhancement at 1 month and 6 months (P<.05), there was no significant difference in UDVA between the 2 groups at the last follow-up (P>.05). At the last follow-up, 36 (73.5%) of the 49 eyes had a UDVA of 20/25 or better and an uncorrected near visual acuity of Jaeger 1 or better concurrently; 46 eyes (93.9%) were within ±1.00 diopter (D) of emmetropia, and 41 (83.7%) were within ±0.50 D. CONCLUSION: Apodized diffractive multifocal IOL implantation and excimer laser enhancement in eyes with previous myopic LASIK provided good results.

Corneal power measurement with a rotating Scheimpflug imaging system after Descemet-stripping automated endothelial keratoplasty.

PURPOSE: To evaluate alterations in corneal power parameters after Descemet-stripping automated endothelial keratoplasty (DSAEK) using rotating Scheimpflug imaging. SETTING: University of Texas, Southwestern Medical Center, Dallas, Texas, USA. METHODS: Eyes that had DSAEK were evaluated with a rotating Scheimpflug imaging system (Pentacam). The outcome parameters were mean anterior and posterior keratometry (K), mean anterior radius of curvature and posterior radius of curvature, anterior and posterior astigmatism, central corneal thickness (CCT), true net power, corneal volume, keratometric power deviation, and mean zonal-equivalent K readings. These values were compared with those in a control group of age and sex-matched normal eyes. RESULTS: The DSAEK group comprised 32 eyes (28 patients) and the control group, 32 eyes. The mean anterior K, posterior K, and true net power were 42.53 diopters (D) +/- 1.52 (SD), -6.80 +/- 0.55 D, and 40.55 +/- 1.79 D, respectively, in the DSAEK group and 43.60 +/- 1.62 D, -6.20 +/- 0.31 D, and 42.49 +/- 1.57 D, respectively, in the control group. The posterior radius of curvature, anterior and posterior K values, and true net power were statistically significantly lower in DSAEK eyes than in control eyes (P<.01). The equivalent K readings were significantly lower in all zones in DSAEK eyes than in control eyes (P<.01). The mean CCT was significantly higher in DSAEK eyes than in control eyes (628 +/- 46 mum versus 553 +/- 35 mum) (P<.01). CONCLUSION: The true net power of the cornea decreased significantly after DSAEK, mainly because of an increase in posterior curvature. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Risk factors for intraocular pressure elevation after descemet stripping automated endothelial keratoplasty.

PURPOSE: To identify the incidence of and risk factors for intraocular pressure (IOP) elevation after Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: Retrospective review was conducted of 68 consecutive DSAEK procedures alone, or in combination with phacoemulsification with intraocular lens implantation or exchange, performed by two surgeons at the University of Texas Southwestern Medical Center between 2005 and 2009. Eyes that developed IOP elevation above 21 mm Hg after DSAEK and requiring initiation or escalation of glaucoma therapy were evaluated. RESULTS: Thirty-seven (54%) eyes showed IOP elevation responsive to medical treatment by a mean follow-up of 11.38 +/- 7.81 months. Six (8.8%) eyes required glaucoma surgery. In the eyes, which developed elevated IOP, gonioscopy did not reveal any new peripheral anterior synechiae formation. Prolonged topical steroid usage, rebubbling, combined DSAEK/cataract surgery, or repeat DSAEK were not significant factors (P>0.05) for development of elevated IOP, but history of previous glaucoma or ocular hypertension (OHTN) was significant (P=0.007). CONCLUSIONS: Intraocular pressure elevation is not uncommon in eyes after DSAEK, but most cases can be controlled with conservative management. Intraocular pressure elevation post-DSAEK occurred by mechanisms other than peripheral anterior synechial angle closure. The only significant risk factor for development of elevated IOP in our series was a previous history of glaucoma or OHTN.

Limbal relaxing incisions at the time of apodized diffractive multifocal intraocular lens implantation to reduce astigmatism with or without subsequent laser in situ keratomileusis.

PURPOSE: To evaluate the visual and refractive outcomes of limbal relaxing incisions (LRIs) to reduce astigmatism at the time of apodized diffractive multifocal intraocular lens (IOL) implantation. SETTING: University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA. METHODS: This retrospective review comprised consecutive patients who had LRIs at the time of lens extraction and AcrySof ReSTOR IOL implantation. A subgroup of patients had subsequent laser in situ keratomileusis (LASIK) for residual refractive error correction. RESULTS: The study evaluated 73 eyes (59 patients); 21 eyes (28.7%) of 59 patients had further LASIK (LRI+LASIK). The mean follow-up was 13.2 months +/- 6.4 (SD). The mean keratometric astigmatism decreased from 1.49 +/- 0.71 diopters (D) preoperatively to 0.56 +/- 0.57 D at the last follow-up (P<.001). Although the LRI+LASIK group had significantly greater corneal astigmatism than the LRI-only group preoperatively (P = .005) and 1 month (P = .030) and 6-months (P = .014) postoperatively, there was no statistically significant difference between the 2 groups at the last follow-up (P = .528). At the last follow-up, the uncorrected distance visual acuity was 20/25 or better and the uncorrected near visual acuity was J1 or better in 32 (76%) of 42 eyes in the LRI-only group and in 17 (81%) of 21 eyes in the LRI+LASIK group. CONCLUSION: Limbal relaxing incisions at the time of apodized diffractive multifocal IOL implantation, with or without subsequent LASIK, were effective and safe in reducing astigmatism.

Corneal higher-order aberrations after Descemet's stripping automated endothelial keratoplasty.

PURPOSE: To compare the corneal higher-order aberration (HOA) after Descemet's stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PKP), and in age-matched controls. DESIGN: Cross-sectional, non-comparative interventional case series. PARTICIPANTS: Thirty-one eyes of 28 patients who underwent DSAEK, 20 eyes of 16 patients who underwent PKP, and 31 eyes of 31 control patients. INTERVENTION: The corneal topography and HOAs of the central 4- and 6-mm zones from anterior and posterior corneal surfaces were evaluated postoperatively with the Scheimpflug rotating imaging system (Oculus Gmbh, Wetzlar, Germany). MAIN OUTCOME MEASURES: Anterior and posterior corneal HOAs. RESULTS: The mean anterior corneal total HOAs of the central 4 and 6 mm were 0.599+/-0.288 microm and 1.215+/-0.496 microm, respectively, in eyes that underwent DSAEK; 1.730+/-0.826 microm and 3.349+/-1.490 microm, respectively, in eyes that underwent PKP; and 0.439+/-0.163 microm and 0.921+/-0.300 microm, respectively, in controls. Although the mean anterior corneal total HOAs of the central 4 and 6 mm were significantly higher in eyes that underwent PKP than in eyes that underwent DSAEK and in controls (P<0.01), there was no significant difference in anterior corneal total HOAs of the central 4 and 6 mm between eyes that underwent DSAEK and controls. The mean posterior corneal total HOAs of the central 4 and 6 mm were 3.680+/-1.586 microm and 7.142+/-3.011 microm, respectively, in eyes that underwent DSAEK; 2.957+/-1.238 microm and 5.314+/-2.095 microm, respectively, in eyes that underwent PKP; and 0.818+/-0.193 microm and 1.609+/-0.344 microm, respectively, in controls. Although there was no significant difference in posterior corneal total HOAs of the central 4 mm between the DSAEK group and the PKP group, the posterior corneal HOAs of the central 6 mm were significantly higher in the DSAEK group than in the PKP group (P<0.01). CONCLUSIONS: Although posterior corneal HOAs are significantly higher in eyes that underwent DSAEK, anterior corneal HOAs are not significantly different in eyes that underwent DSAEK than those of age-matched controls.

Outcomes of LASIK and PRK in previous penetrating corneal transplant recipients.

OBJECTIVE: To evaluate the safety and efficacy of excimer laser refractive surgery in correcting refractive error in eyes that have undergone previous penetrating keratoplasty (PK). METHODS: Twenty-three keratorefractive procedures on 16 eyes from 16 consecutive subjects were evaluated between 2002 and 2008. Each patient presented a previous history of a PK with subsequent postoperative myopia and astigmatism. Keratometric value, manifest refraction, best-corrected visual acuity, uncorrected visual acuity, and complications were determined. RESULTS: There were a total of 14 photorefractive keratectomy (PRK) procedures performed on 11 eyes and 9 laser in situ keratomileusis (LASIK) procedures performed on 5 eyes. In the PRK group, the preoperative post-PK manifest refractive spherical equivalent and cylindrical error were -6.22 +/- 6.23 diopter and 5.23 +/- 2.26 D, respectively. The PRK postoperative manifest refractive spherical equivalent and cylindrical error were -3.61 +/- 4.23 D (P=0.25) and 3.21 +/- 1.78 D (P=0.02), respectively. In the LASIK group, the preoperative post-PK manifest refractive spherical equivalent and cylindrical error were -3.05 +/- 3.29 D and 4.11 +/- 2.38 D, respectively. The LASIK postoperative manifest refractive spherical equivalent and cylindrical error were -1.51 +/- 2.02 D (P=0.24) and 2.08 +/- 1.26 D (P=0.03), respectively. There was a 2-line or greater improvement of uncorrected visual acuity in 8 of the 14 PRK treatments and 5 of the 9 LASIK treatments. There were two episodes of acute graft rejection. One of the episodes resolved with topical and oral corticosteroids, and the other episode required a repeat corneal transplantation. CONCLUSIONS: PRK and LASIK are effective tools in reducing surgically induced astigmatism after penetrating corneal transplantation in most patients in this case series. The reduction of astigmatism may allow improved contact lens or spectacle fitting to achieve best-corrected binocular visual acuity.

Quality of life changes after myopic wavefront-guided laser in situ keratomileusis.

OBJECTIVE: To evaluate the changes in quality of life in patients undergoing wavefront-guided laser in situ keratomeilusis (WG-LASIK). METHODS: Thirty candidates undergoing WG-LASIK were enrolled in a prospective study at the University of Texas Southwestern Medical Center at Dallas, TX. The patients were asked to fill out a questionnaire which had questions pertaining to their quality of life, preoperatively and 3 months postoperatively. The average patients' age was 41.4 +/- 12.45 years, and the preoperative manifest refractive spherical equivalent was -3.62 +/- 1.60 D (-1.00 to -7.50 D). RESULTS: The total quality-of-life score improved from 3.70 +/- 0.91 to 3.90 +/- 0.97 (P = 0.01). Most of the psychologic well-being items like energy level, stress level, self-confidence, sense of safety, and the social role subscale items such as ability to communicate with others, job performance, and sex life showed significant improvement in mean scores (P < 0.05). The postoperative visual function and visual symptom scores, however, were overall similar to preoperative levels. CONCLUSIONS: Consistent with previous studies with conventional LASIK, there is a significant improvement in quality of life after WG-LASIK. The main changes pertain to psychologic well-being and social role, more than the changes in visual function per se. However, the latter did not show evidence of deterioration, nor of worsening of visual symptoms, contrary to some studies with conventional LASIK.

Laser in situ keratomileusis for residual refractive errors after apodized diffractive multifocal intraocular lens implantation.

PURPOSE: To evaluate the visual and refractive outcomes of laser in situ keratomileusis (LASIK) to correct residual refractive error after apodized diffractive multifocal intraocular lens (IOL) implantation. SETTING: University of Texas Southwestern Medical Center, Dallas, Texas, USA. METHODS: This retrospective study reviewed eyes of consecutive patients who had LASIK using the IntraLase FS60 femtosecond laser and Visx Star S4 excimer laser to correct residual refractive error after AcrySof ReSTOR IOL implantation. RESULTS: The review comprised 85 eyes of 59 patients. Thirty-six eyes (42.3%) had myopic correction, 35 (41.2%) had mixed astigmatic correction, and 14 (16.5%) had hyperopic correction; 45 eyes (52.9%) also had neodymium:YAG (Nd:YAG) capsulotomy. Six months after LASIK, 91.8% of eyes had an uncorrected distance visual acuity (UCVA) of 20/25 or better, 92.9% had an uncorrected near visual acuity (UCNVA) of J1 or better, and 85.9% had 20/25 or better UCVA concurrent with J1 or better UCNVA. No eye lost more than 1 line of best spectacle-corrected visual acuity; 2 eyes (2.4%) lost 1 line. Ninety-nine percent of eyes were within +/-1.00 diopter (D) of emmetropia, and 98% of eyes were within +/-1.00 D cylinder. There was no significant difference in postoperative UCVA or UCNVA between the 3 refraction groups (P >.05) or between eyes that had Nd:YAG capsulotomy and those that did not (P >.05). CONCLUSION: Laser in situ keratomileusis for residual ametropia after apodized diffractive multifocal IOL implantation was predictable, effective, and safe.

Corneal refractive power estimation and intraocular lens calculation after hyperopic LASIK.

PURPOSE: To identify key independent variables in estimating corneal refractive power (KBC) after hyperopic LASIK. DESIGN: Retrospective study. PARTICIPANTS: We included 24 eyes of 16 hyperopic patients who underwent LASIK with subsequent phacoemulsification and posterior chamber intraocular lens (IOL) implantation in the same eye. METHODS: Pre-LASIK and post-LASIK spherical equivalent (SE) refractions and topographies, axial length, implant type and power, and 3-month postphacoemulsification SE were recorded. Using the double-K Hoffer Q formula, corneal power was backcalculated for every eye (KBC), regression-based formulas derived, and corresponding IOL powers calculated and compared with published methods. MAIN OUTCOME MEASURES: The Pearson correlation coefficient (PCC) and arithmetic and absolute corneal and IOL power errors. RESULTS: Adjusting either the average central corneal power (ACCP(3mm)) or SimK based on the laser-induced spherical equivalent change (DeltaSE) resulted in an estimated corneal power (ACCP(adj) and SimK(adj)) with highest correlation with KBC (PCC=0.940 and 0.956, respectively) and lowest absolute corneal estimation error (0.37+/-0.45 and 0.38+/-0.39 diopter [D], respectively). The ACCP(adj) closely mirrored published DeltaSE-based adjustments of central corneal power on different topographers, whereas DeltaSE-based SimK adjustments varied across platforms. Using ACCP(adj) or SimK(adj) in the double-K Hoffer Q, using ACCP(3mm) or SimK in single-K Hoffer Q and adjusting the resultant IOL power based on DeltaSE, or applying Masket's formula all yielded accurate and similar IOL powers. The Latkany method consistently underestimated IOL power. The Feiz-Mannis and clinical history methods yielded poor IOL correlations and large IOL errors. CONCLUSION: After hyperopic LASIK, adjusting either corneal power or IOL power based on DeltaSE accurately estimates the appropriate IOL power.

Outcomes of PermaVision intracorneal implants for the correction of hyperopia.

PURPOSE: To report the clinical and visual outcomes of a series of patients implanted with the PermaVision intracorneal lens (ReVision Optics Inc, Lake Forest, California, USA) for correction of hyperopia. DESIGN: Prospective, nonrandomized, clinical trial study. METHODS: Fifteen patients were implanted with the intracorneal lens for correction of spherical hyperopic refractive errors ranging from 1.00 to 5.00 diopters (D) (mean, 2.45 D). All eyes were correctable to 20/20 before surgery. Patients were followed up to 3 years with measurements of residual refractive error, uncorrected visual acuity (UCVA), and best spectacle-corrected visual acuity (BSCVA). RESULTS: For patients with follow-up of 1 year or more, the mean logarithm of the minimum angle of resolution BSCVA was 0.15 (20/28 Snellen equivalent; range, 0.1 to 0.6) with an average change of -2.5 lines of BSCVA (range, 1 to -6 lines). Only 3 eyes (25%) achieved 20/20 or better UCVA. Two patients experienced early adverse events and 1 patient experienced a late-onset adverse event requiring eventual removal of the implant. Nine patients elected to have the implant removed, with dissatisfaction with the quality of vision as the most frequent reason for removal. CONCLUSIONS: The quality of visual and refractive outcomes with this device was less than satisfactory for most of the patients in our series. Although the problems of early onset migration or extrusion of the device are possible, late-onset ulceration noted in one of our patients most likely represents a neurotropic melt. Further research to improve the safety and quality of refractive result with intracorneal implants is needed.

Corneal deturgescence after Descemet stripping automated endothelial keratoplasty evaluated by Visante anterior segment optical coherence tomography.

PURPOSE: To evaluate postoperative corneal deturgescence after Descemet stripping endothelial keratoplasty (DSAEK) using the Visante anterior segment optical coherence tomography (OCT) system (Carl Zeiss Meditec Inc, Dublin, California, USA). DESIGN: Retrospective case series. METHODS: We included 21 eyes (9 males and 12 females; mean age +/- standard deviation, 76.3 +/- 12 years). The Visante OCT system was used to determine the central and peripheral endothelial keratoplasty graft thickness and total central and peripheral corneal thickness. RESULTS: Central graft thickness decreased from the first day (243.3 +/- 92 microm) to the last visit (147.8 +/- 44 microm; P = .0001). The rate of central graft thinning slowed during the following intervals: during the first week (47 microm), at 1 week to 1 month (40 microm), and at 1 to 6 months (25 microm), with a mild increase at 6 to 9 months (5 microm). Peripheral graft thickness continued to decrease from postoperative day 1 (318.5 +/- 99 microm) to the last visit (196.7 +/- 50 microm; P = .0001). There was a decrease in total central corneal thickness from day 1 (903.8 +/- 179 microm) to the last visit (671 +/- 93 microm; P = .0001). All patients were imaged with the Visante OCT at the first 4 defined postoperative intervals; however, only 9 eyes were imaged at the last interval of 6 to 9 months. CONCLUSIONS: After DSAEK, there is a greater thinning of the central graft compared with the peripheral graft. The central cornea thickness decreases and peripheral corneal thickness increases. Central corneal graft deturgescence stabilizes by 6 months after surgery.

Assessment of keratocyte activation following LASIK with flap creation using the IntraLase FS60 laser.

PURPOSE: To assess the response of corneal keratocytes to the IntraLase FS60 femtosecond laser using attenuated steroids. METHODS: Thirty patients (30 eyes) who underwent LASIK with the IntraLase FS60 were assessed by clinical examination and confocal microscopy 3 months postoperatively. Postoperative steroid regimen was Econopred Plus (Alcon Laboratories Inc) every hour for 1 day and four times daily for 7 days. RESULTS: No cornea had clinically significant flap interface haze. Two corneas had trace haze at the interface detected by slit-lamp examination; both showed significant keratocyte activation by confocal microscopy. Overall, some degree of keratocyte activation was detected at the flap interface in 10 of 30 eyes. The measured interface reflectivity was 328.8 +/- 85.0 confocal backscatter units (CBU) in eyes with activated keratocytes and 88.9 +/- 74.5 CBU for the remaining 19 eyes (P < .001). CONCLUSIONS: With attenuated steroids, keratocyte activation was found in a significant number of eyes, although interface haze was subclinical. A higher steroid dosage might therefore be indicated.

Intraocular lens power calculation after myopic laser in situ keratomileusis: Estimating the corneal refractive power.

PURPOSE: To derive regression-based formulas and identify essential dependent variables to estimate refractive corneal power after myopic laser in situ keratomileusis (LASIK). SETTING: University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA. METHODS: A retrospective data review of 30 eyes (23 patients) having myopic LASIK followed by phacoemulsification and posterior chamber intraocular lens (IOL) implantation in the same eye gathered the following: pre-LASIK and post-LASIK refractions and topographies, axial length, IOL type and power, and spherical equivalent (SE) refraction 3 months after phacoemulsification. Using the double-K Holladay 1 formula, the refractive corneal power in each eye was back-calculated. Regression formulas were derived and compared with current corneal power estimation methods. RESULTS: The multiple regression formula based on the average corneal power in the central 3.0 mm area (ACCP3 mm) and the change (Delta) in SE (SEpostLASIK-SEpreLASIK) was simplified to ACCPadj=ACCP3mm-0.16DeltaSE, with the highest Pearson correlation coefficient (r=0.989) and lowest absolute corneal power estimation error (0.30 diopter [D]+/-0.30 (SD)). Regression based on ACCP3 mm alone yielded 0.980 and 0.49+/-0.40 D, respectively. Using SimK with DeltaSE resulted in a lower r value (0.971) and larger absolute corneal power estimation error (0.65+/-0.44 D) (P=.0014). The clinical history methods yielded 0.909 and 1.09+/-0.868 D, respectively (P=.0005). CONCLUSION: The regression formula based on ACCP3mm and DeltaSE was very accurate in predicting refractive corneal power after myopic LASIK followed by formulas based on ACCP3mm alone and SimK and DeltaSE, all of which consolidate the validity of similar previously suggested methods, including EffRPadjusted.