Pawan Prasher

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.

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.

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.

Tandem Scanning Confocal Microscopy of Cornea After Descemet Stripping Automated Endothelial Keratoplasty

Purpose: To evaluate the changes in the corneal stroma after Descemet stripping automated endothelial keratoplasty (DSAEK) using tandem scanning confocal microscopy (CM). Methods: Thirteen eyes of 13 patients who underwent DSAEK without preoperative corneal haze or scar obvious at the slit lamp, any ocular disease, and postoperative complication were included in the study. All patients were examined clinically and by CM 6 months after DSAEK. Results: Six months after DSAEK, none of the eyes had clinically significant interface haze (i.e., haze affecting quantity or quality of vision) at slit lamp. The mean best spectacle corrected visual acuity was 0.18 ± 0.12 (range 0–0.4) logMAR (Snellen 20/30). The CM revealed highly reflective particles in interface in six eyes, particles with mild surrounding increased reflectivity in four eyes, and no discernible interface in three eyes. The mean particles density at interface was 28.6 ± 23.4 particles/mm2. No significant keratocyte activation was seen in any case at the interface. The mean anterior stromal reflectivity was 431.2 ± 269.1 confocal back scatter units (CBU) and the mean interface reflectivity was 65.9 ± 46.9 CBU. The mean anterior stromal reflectivity was significantly greater than the mean interface reflectivity (P<0.01). Significant keratocyte activation with high reflectivity was seen in superficial anterior stroma in 8 of 13 eyes. Conclusions: Tandem scanning CM shows the presence of highly reflective particles at the level of the DSAEK interface that are morphologically similar to a laser in situ keratomileusis interface. The stromal reflectivity is more prominent in subepithelial layers than that of interface 6 months after DSAEK. However, the areas under the mean reflectivity peaks (CBU) corresponding to the flap interface and superficial anterior stroma do not seem to correlate with best spectacle corrected visual acuity results after the procedure.

Evaluation of the role of ProKera in the management of ocular surface and orbital disorders.

Objectives: To report the efficacy and safety profile of sutureless and adhesiveless amniotic membrane device (ProKera, Bio-Tissue, Inc., Miami, FL) in the management of various ocular surface and orbital disorders. Methods: Twenty eyes of 20 patients underwent placement of 21 ProKera implants between March 2006 and July 2007 at the University of Texas Southwestern Medical Center. Patient demographics, indications for placement, and duration of ProKera retention were recorded. Outcomes measured included corneal epithelial healing, visual acuity, patient tolerance, and adverse events. Results: ProKera was most commonly used in patients with corneal neovascularization with or without limbal stem-cell deficiency (10 eyes). Other indications included recurrent pterygium or pseudopterygium (three eyes), anophthalmic orbit contraction (two eyes), persistent epithelial defects (two eyes), severe thinning in a corneal ulcer (one eye), benign hereditary intraepithelial dyskeratosis (one eye), and band keratopathy (one eye). The mean duration of ProKera retention was 25.3 days (range, 0–125) visual acuity improved in 12 eyes (60%). Immediate adverse events included residual epithelial defects after removal (five eyes) and spontaneous extrusion of the implant (four eyes). Six patients (30%) reported eye pain or headache and four eyes (20%) had recurrence of the primary pathology. Conclusions: Sutureless and adhesiveless amniotic membrane transplantation is a safe and effective method to promote healing and reconstruction of the ocular surface and orbit with minimal side effects. Recurrence of the underlying primary pathology remains a concern. The advent of a newer, softer conformer ring may improve patient tolerability and limit discomfort.

Features of Urrets-Zavalia syndrome after descemet stripping automated endothelial keratoplasty.

Purpose: To report a case series of pupil abnormalities consistent with features of Urrets-Zavalia syndrome (UZS) after Descemet stripping automated endothelial keratoplasty (DSAEK) for corneal edema secondary to corneal endothelial cell dysfunction. Methods: Retrospective chart analysis of subjects who developed UZS after DSAEK at the University of Texas Southwestern Medical Center. Results: We present a series of 7 eyes with features consistent with UZS, after undergoing DSAEK. Elevated intraocular pressures (IOP) were noted in the early postoperative period in all cases. Five of 7 had graft dislocation in the postoperative period and required rebubbling or repeat DSAEK to obtain a well-apposed graft. Patients were followed for 3 to 14 months and showed improvement in visual acuity and IOP, but fixed dilated pupils persisted. Conclusion: A fixed irregular or dilated pupil is a rare complication that can be associated with DSAEK surgery. Patients with an elevated IOP and complicated postoperative course seem to be at greater risk for developing iris ischemia and pupil abnormalities consistent with the diagnosis of UZS.

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 μm versus 553 ± 35 μm) (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.

Herpetic keratitis after descemet stripping automated endothelial keratoplasty for failed graft.

Objectives: To report a case of herpetic epithelial keratitis after Descemet stripping automated endothelial keratoplasty (DSAEK) for a failed graft. Methods: A 31-year-old female patient underwent DSAEK for failed graft in left eye. She previously had undergone penetrating keratoplasty for keratoconus in that eye. Results: One week after DSAEK, the patient presented with pain in left eye. The cornea showed two epithelial defects with dendritic edges that involved the penetrating keratoplasty graft host junction and showed positive fluorescein staining. Diagnosis of herpes simplex virus keratitis was made and the patient was started on oral acyclovir and topical trifluiridine. The epithelial lesions showed complete resolution in 3 days. Conclusions: Herpes simplex virus epithelial keratitis can occur after DSAEK for failed grafts even in the absence of previous history of herpes simplex virus infection and should be considered in the differential diagnosis of postoperative epithelial defects.

Traumatic graft dehiscence after anterior lamellar keratoplasty

A 64-year-old man underwent anterior lamellar keratoplasty using the Melles technique for corneal scar secondary to healed bacterial keratitis in the left eye. Two months postoperatively, the patient presented with blurry vision in the left eye after a fall in the bathroom. The uncorrected visual acuity was 20/400 in the left eye, and the external examination showed periorbital swelling with ecchymosis. Slit-lamp examination revealed an absent graft, a circular crater in the center, and a fragment of suture on the temporal edge of the crater. The Seidel test was negative, and there was no sign of infection. The anterior segment optical coherence tomography showed intact residual stroma with slight forward protrusion. The patient underwent repeat anterior lamellar corneal transplantation with improvement in uncorrected visual acuity of 20/100 and best spectacle-corrected visual acuity of 20/70 in the left eye 3 months postoperatively.