V. Vinod Mootha

Corneal Higher-Order Aberrations after Descemet's Stripping Automated Endothelial Keratoplasty

PURPOSE To compare the corneal higher-order aberration (HOA) after Descemets 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.

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.

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

Purpose: To report a rare case of large conjunctival B-cell lymphoma in a child. Methods: A 13-year-old girl was initially diagnosed with a right lower eyelid chalazion. After 3 weeks during which the mass was growing, she was referred for treatment to our department. Because of the unusual appearance of the mass, an excisional biopsy was performed. Results: Pathological findings were consistent with those of a large B-cell lymphoma. CD20 and Ki67 staining were positive, and polymerase chain reaction analysis showed monoclonality of B cells. Conclusions: Although conjunctival lymphoma is a very rare entity in children, it should be included in the differential diagnosis of an eyelid or conjunctival mass.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.

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 (ACCP3mm) and the change (Δ) in SE (SEpostLASIK − SEpreLASIK) was simplified to ACCPadj = ACCP3mm − 0.16ΔSE, 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 ACCP3mm alone yielded 0.980 and 0.49 ± 0.40 D, respectively. Using SimK with ΔSE 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 ΔSE was very accurate in predicting refractive corneal power after myopic LASIK followed by formulas based on ACCP3mm alone and SimK and ΔSE, all of which consolidate the validity of similar previously suggested methods, including EffRPadjusted.

Epithelial downgrowth after descemet stripping automated endothelial keratoplasty

Purpose: To report the clinical and histopathologic findings of 2 patients who developed epithelial downgrowth after Descemet stripping automated endothelial keratoplasty (DSAEK). Methods: A 64-year-old woman (case 1) underwent DSAEK for corneal edema secondary to Fuchs endothelial dystrophy in left eye. However, the graft failed to attach, and a repeat DSAEK was performed 3 weeks later. After 4 months, the patient developed herpes simplex virus keratitis that resulted in anterior stromal scarring. A penetrating keratoplasty was performed 15 months after the initial DSAEK. Our second patient (case 2) was an 87-year-old female who underwent DSAEK for corneal edema secondary to Fuchs endothelial dystrophy in left eye. Six months later, she had an episode of graft rejection and developed secondary glaucoma. At 14 months postoperatively, a retrocorneal membrane was seen involving the temporal half of the endothelial surface of the graft. The retrocorneal membrane extended from the inferior thickened edge of the endothelial keratoplasty graft to the iris stromal surface. An Ahmed shunt implantation followed by repeat DSAEK were then performed. The excised corneal buttons were examined. Results: Histopathologic evaluation showed multilayered epithelium on the interface and attenuated endothelium in the endothelial graft in case 1. The host cornea showed diffuse stromal scarring. Case 2 showed multilayered epithelium with early cyst formation at the edge of the graft. The epithelium extended to involve the endothelial surface without involvement of interface surface. Significant scar formation was observed between the edge of the endothelial keratoplasty graft and thickened host Descemet membrane. Some pigmented cells were present within the epithelial downgrowth. The epithelium stained positively with cytokeratin A1/A3 in both cases. Conclusions: Although rare, epithelial downgrowth can occur after DSAEK and can be associated with graft failure. Early recognition and surgical treatment of epithelial downgrowth is crucial in treating the complications of corneal decompensation and glaucoma.

A multicenter study to map genes for Fuchs endothelial corneal dystrophy: Baseline characteristics and heritability

Purpose: To describe the methods for family and case–control recruitment for a multicenter genetic and associated heritability analyses of Fuchs endothelial corneal dystrophy (FECD). Methods: Twenty-nine enrolling sites with 62 trained investigators and coordinators gathered individual and family information, graded the phenotype, and collected blood and/or saliva for genetic analysis on all individuals with and without FECD. The degree of FECD was assessed in a 0 to 6 semiquantitative scale using standardized clinical methods with pathological verification of FECD on at least 1 member of each family. Central corneal thickness was measured by ultrasonic pachymetry. Results: Three hundred twenty-two families with 330 affected sibling pairs with FECD were enrolled and included a total of 650 sibling pairs of all disease grades. Using the entire 7-step FECD grading scale or a dichotomous definition of severe disease, heritability was assessed in families via sib–sib correlations. Both binary indicators of severe disease and semiquantitative measures of disease severity were significantly heritable, with heritability estimates of 30% for severe disease, 37% to 39% for FECD score, and 47% for central corneal thickness. Conclusions: Genetic risk factors have a strong role in the severity of the FECD phenotype and corneal thickness. Genotyping this cohort with high-density genetic markers followed by appropriate statistical analyses should lead to novel loci for disease susceptibility.

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.

Comparison of the corneal response to laser in situ keratomileusis with flap creation using the FS15 and FS30 femtosecond lasers: clinical and confocal microscopy findings.

PURPOSE: To compare the response of the cornea to laser in situ keratomileusis (LASIK) with flap creation using the IntraLase FS15 or FS30 femtosecond laser (IntraLase Corp.). SETTING: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, USA. METHODS: Twenty‐three patients (31 eyes) who had LASIK with flap creation using the FS15 or FS30 laser were assessed by clinical examination and confocal microscopy in a nonrandomized parallel treatment group comparative trial. Eight FS15 patients (15 eyes) were examined preoperatively and 3 months postoperatively, and 14 FS30 patients (15 eyes) were examined 3 months postoperatively. RESULTS: No patient in either group had clinically significant flap interface haze. One FS15 eye and 1 FS30 eye had significant keratocyte activation at the flap interface. The mean difference between the actual flap thickness and intended flap thickness was 16.8 μm ± 11.1 (SD) and 13.9 ± 7.1 μm in the FS15 group and FS30 group, respectively (P = .49). The mean measured interface reflectivity was 156.4 ± 88.6 confocal backscatter units (CBU) and 104.8 ± 91.2 CBU, respectively (P = .15). The mean density of interface particles was 21.4 ± 14.8 particles/mm2 in the FS15 group and 11.0 ± 7.1 particles/mm2 in the FS30 group (P<.05). CONCLUSIONS: Both the FS15 and FS30 lasers provided more reproducible flap thickness and fewer interface particles than previously observed using microkeratomes. The response of corneal keratocytes to intra‐LASIK was reduced compared with previous results in which higher raster energies were used. Compared with the FS15, there was an apparent reduction in overall interface reflectivity and fewer interface particles with the FS30 laser.

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.

Intraocular lens power calculation after radial keratotomy : Estimating the refractive corneal power

PURPOSE: To evaluate the most accurate method for corneal power determination in patients with previous radial keratotomy (RK). SETTING: University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA. METHODS: A retrospective review of data for 16 eyes of 14 patients with a history of RK and subsequent phacoemulsification and posterior chamber intraocular lens (IOL) implantation was performed. Outcome measures included axial length, postoperative topography, type and power of IOL implanted, and postoperative spherical equivalent (SE) refraction at 3 to 6 months. Average central corneal power (ACCP) was defined as the average of the mean powers of the central Placido rings. For each eye, simulated K‐readings and different values of ACCP computed corresponding to different central corneal diameters were used in each case, along with the implanted IOL power, to back‐calculate the SE refraction (Ref) via the double‐K adjusted Holladay 1 IOL formula. The predicted refractive error was hence computed as (Ref – SE), both in algebraic and absolute values. RESULTS: The ACCP over the central 3.0 mm (ACCP3mm) yielded the lowest absolute predicted refractive error (0.25 ± 0.38 diopters [D]), which was statistically lower than the error for ACCP1mm (P<.001) and for the simulated K‐value (P = .033). It also resulted in 87.5% of eyes being within ±0.50 D and 100% within ±1.00 D of the actual postoperative refraction. CONCLUSIONS: Corneal refractive power after RK was best described by averaging the topographic data of the central 3.0 mm area. Applying this method, together with a double‐K IOL formula, achieved excellent IOL power predictability.