Keith Andrew Walter

5-Fluorouracil for the treatment of intraepithelial neoplasia of the conjunctiva and cornea

OBJECTIVE To evaluate the efficacy of pulse dosing of topical 5-fluorouracil (5-FU) in the treatment of conjunctival and corneal intraepithelial neoplasia. DESIGN Prospective, noncomparative case series. PARTICIPANTS Seven patients with histologic evidence of intraepithelial neoplasia were identified by conjunctival biopsy or tumor excision. METHODS Seven patients with a minimum of 7 months of follow-up were treated with pulsed dosing of 1% 5-FU. Topical 1% 5-FU was administered four times daily for 2 to 4 days for each cycle. The number of initial treatment cycles was two to six, with the time between cycles being 30 to 45 days. MAIN OUTCOME MEASURES The presence or absence of clinically evident intraepithelial neoplasia was evaluated after each treatment interval. Patients were also monitored for adverse reactions to the use of topical 5-FU. RESULTS Four patients remain disease free with a mean follow-up of 18.5 months (range, 7-36 months) with no additional treatment after the initial treatment cycles (mean, 3.75 cycles; range, 2-5 cycles). Three patients had recurrence of disease after the initial treatment cycles. Two patients were treated with additional cycles for recurrent disease (six cycles in one patient and five cycles in the other patient) and are free of disease at 20 and 21 months after treatment, respectively. One patient had persistent disease despite treatment with topical 5-FU and was treated with topical mitomycin C with resolution of the disease without recurrence for 16.5 months. No adverse reactions to pulse dose treatment with topical 5-FU were noted. CONCLUSIONS Pulsed dosing with 1% topical 5-FU for the treatment of conjunctival and corneal intraepithelial neoplasia, alone or as an adjunct to excision of bulky disease, is a well-tolerated and effective method of treatment.

Bioengineering endothelialized neo-corneas using donor-derived corneal endothelial cells and decellularized corneal stroma.

Corneal transplantation is a common transplant procedure performed to improve visual acuity by replacing the opaque or distorted host tissue by clear healthy donor tissue. However, its clinical utility is limited due to a lack of high quality donor corneas. Bioengineered neo-corneas, created using an expandable population of human donor-derived corneal endothelial cells (HCEC), could address this current shortage. The objectives of this study were to establish HCEC isolation and culture protocols and to investigate the feasibility of bioengineering corneal tissue constructs by seeding the cells on decellularized human corneal stroma. HCECs were removed from the discarded corneas of eye donors by enzymatic digestion. Cells were expanded and evaluated for their expression of Na(+)/K(+)-ATPase and zona occludens-1 (ZO-1). Donor corneal stromas were cut to 120-200 microm thickness slices using a microtome and then decellularized. Extracellular matrix components and mechanical properties of the scaffolds were measured after decellularization. To engineer neo-corneas, 130 HCEC/mm(2) were seeded on decellularized human corneal stromas. The resulting constructs were placed in growth medium for 14 days and then analyzed using scanning electron microscopy (SEM), histology, and immunocytochemistry. Seeded cells retain expression of the functional markers Na(+)/K(+)-ATPase and ZO-1 and constructs have biomechanical properties similar to those of normal corneas. These results indicate that construction of neo-corneas, using HCECs derived from discarded donor corneas and decellularized thin-layer corneal stromas, may create a new source of high quality corneal tissue for transplantation.

Accurate intraocular lens power calculation after myopic laser in situ keratomileusis, bypassing corneal power

PURPOSE: To describe a novel method for calculating intraocular lens (IOL) power after myopic laser in situ keratomileusis (LASIK) without using the inaccuracies of the post‐LASIK corneal power. SETTING: Department of Ophthalmology, Wake Forest University Eye Center, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA. METHODS: This retrospective chart review comprised 9 eyes of 9 patients who had phacoemulsification after LASIK using our method for IOL calculation. This new method assumes the patient never had myopic LASIK to calculate IOL power and then targets the IOL at the pre‐LASIK amount of myopia. The pre‐LASIK keratometry values, pre‐LASIK manifest refraction, and the current axial length are placed in the Holladay formula, bypassing the post‐LASIK corneal power. In theory, assuming that the patient had satisfactory LASIK results, the correct IOL can then be determined. RESULTS: The mean spherical equivalent postoperative refraction was +0.03 diopter (D) ± 0.42 (SD) (range −0.625 to +0.75 D). In all 9 eyes, our method consistently chose the most accurate and precise IOL compared with other methods. CONCLUSIONS: The new method of calculating IOL power after LASIK provided excellent results and the most accurate and precise results to date.

Over-the-counter decorative contact lenses: Cosmetic or Medical Devices? A Case Series.

Purpose. To illustrate the implications of the unauthorized sale and unmonitored wearing of decorative cosmetic contact lenses resulting in ocular complications and to determine the prevalence of the use of cosmetic contact lenses obtained from unlicensed providers by adolescents. Methods. Observational case report, structured interview, and survey in a retrospective, observational, clinical practice setting. Reported sources of contact lenses were categorized as provider and nonprovider, and associations within the data were reviewed by using a Pearson correlation and chi-square test. Results. Twelve patients (eight female and four male) were seen urgently for acute eye pain and redness after wearing plano decorative contact lenses. None of the patients had previously worn a contact lens. None of the lenses were dispensed by eye care professionals. Four patients developed blinding infections requiring hospital admission. Causative organisms included staphylococci, Pseudomonas, and acanthamoeba. One patient required a penetrating keratoplasty. One hundred fifty-nine patients were surveyed. Thirty-seven (23%) used decorative contact lenses. Lenses were obtained from an unlicensed provider 51% of the time. Education about lens care and handling was significantly associated with acquiring lenses from licensed providers (R = 0.74, P<0.0001). Conclusions. Colored noncorrective contact lenses are being dispensed without a prescription or fitting from unlicensed vendors. Patients who acquire lenses from unauthorized providers are significantly less likely to be instructed on appropriate lens use and care. Consequently, uninformed lens wearers are experiencing acute vision-threatening infections and inflammation.

Effect of environmental factors on myopic LASIK enhancement rates

Purpose: To determine whether environmental factors affect laser in situ keratomileusis (LASIK) enhancement rates. Setting: Wake Forest University Eye Center, Winston‐Salem, North Carolina, USA. Methods: This retrospective chart review comprised 368 consecutive eyes of 191 myopic patients who had LASIK by the same surgeon (K.A.W.). All patients had surgery in 2000 with the Visx Star S2 excimer laser. Refractive outcome, visual acuity, and enhancement rates were monitored closely for 1 year. Fifty‐seven eyes (15.5%) had an enhancement procedure. Using enhancement procedure or percentage of correction as the outcome measure, factors that were suspected to affect LASIK results and the need for enhancement were examined; specifically, age, eye, sex, pachymetry, corneal curvature (K), preoperative spherical equivalent, ablation depth, and environmental factors (procedure room temperature, procedure room relative humidity, outdoor temperature, and outdoor relative humidity). Results: Using univariate and multivariate analysis, LASIK enhancement rates strongly correlated with the following variables: procedure room humidity (P = .003; odds ratio [OR] = 1.093; 95% confidence intervals [CI], 1.030‐1.160), 2‐week preoperative mean outdoor humidity (P = .011; OR = 1.054; 95% CI, 1.012‐1.096), outdoor temperature (P = .0059; OR = 1.039; 95% CI, 1.011‐1.068), and age (P = .0497; OR = 1.034; 95% CI, 1.001‐1.070). The percentage of correction strongly correlated with the following variables: procedure room humidity (P = .021), 2‐week preoperative mean outdoor humidity (P = .001), outdoor temperature (P = .0052), and room temperature (P = .017). Conclusions: The 2‐week‐preoperative mean outdoor relative humidity, procedure room relative humidity, outdoor temperature, and procedure room temperature may have to be considered during LASIK planning. The effect of these environmental variables on LASIK outcomes warrants further evaluation.

Retrospective analysis of a novel method of transscleral suture fixation for posterior-chamber intraocular lens implantation in the absence of capsular support.

Purpose To determine the safety and efficacy of an alternative method for transscleral fixation of a secondary posterior-chamber intraocular lens (pcIOL) during penetrating keratoplasty. Methods Eighty-nine eyes that underwent secondary pcIOL implantation by using a modified transscleral suture-fixation technique during penetrating keratoplasty were retrospectively evaluated. The surgical technique used suture fixation to the surface of the sclera 5 mm posterior to the limbus, with the knot buried beneath Tenons capsule and conjunctiva. Patient records were reviewed for postoperative complications, including suture erosion, pcIOL subluxation, vitreous hemorrhage, and retinal detachment. Mean follow-up was 24.4 months, with a range of 4–68 months. Results All eyes had successful fixation of their pcIOL immediately after surgery. Three (3.3%) eyes had graft failure. Six (6.7%) of 89 eyes showed evidence of suture erosion or partial exposure. Postoperative suture breakage occurred in two (2.2%) eyes. Posterior-segment complications included retinal detachment in one (1.1%) eye, vitreous hemorrhage in one (1.1%) eye, and limited choroidal hemorrhage in two (2.2%) eyes. Median visual acuity at 1-year follow-up was 20/70 (range, 20/25 to light perception). Conclusion This transscleral fixation technique provides a straightforward alternative to previously described techniques. Suture erosion, IOL dislocation, and posterior-segment complications occurred at relatively low rates compared with other pcIOL implantation techniques.

Dysfunctional tear syndrome: dry eye disease and associated tear film disorders - new strategies for diagnosis and treatment.

Dysfunctional tear syndrome (DTS) is a common and complex condition affecting the ocular surface. The health and normal functioning of the ocular surface is dependent on a stable and sufficient tear film. Clinician awareness of conditions affecting the ocular surface has increased in recent years because of expanded research and the publication of diagnosis and treatment guidelines pertaining to disorders resulting in DTS, including the Delphi panel treatment recommendations for DTS (2006), the International Dry Eye Workshop (DEWS) (2007), the Meibomian Gland Dysfunction (MGD) Workshop (2011), and the updated Preferred Practice Pattern guidelines from the American Academy of Ophthalmology pertaining to dry eye and blepharitis (2013). Since the publication of the existing guidelines, new diagnostic techniques and treatment options that provide an opportunity for better management of patients have become available. Clinicians are now able to access a wealth of information that can help them obtain a differential diagnosis and treatment approach for patients presenting with DTS. This review provides a practical and directed approach to the diagnosis and treatment of patients with DTS, emphasizing treatment that is tailored to the specific disease subtype as well as the severity of the condition.

Severe corneal toxicity after topical fluoroquinolone therapy: report of two cases.

Purpose: To describe 2 cases of sterile corneal ulcers that persisted after several weeks of therapy with topical moxifloxacin 0.5% but that resolved when antibiotic therapy was changed. Methods: Small case series. Results: Both cases presented here describe corneal ulcers that persisted and showed signs of worsening during weeks of frequent topical dosing with moxifloxacin. Descemet folds and an atypically large amount of stromal edema were present in both cases, and there appeared to be possible endothelial dysfunction as well. There was no sign of bacterial, viral, or fungal infection in either case. In both cases, healing began a few days after moxifloxacin was discontinued, and topical gatifloxacin and corticosteroids were initiated. Conclusion: These cases suggest that moxifloxacin may interfere with the healing of corneal ulcers.

Small-incision Descemet stripping automated endothelial keratoplasty: a comparison of small-incision tissue injector and forceps techniques.

Purpose: To describe a novel, small-incision, no-fold Descemet stripping automated endothelial keratoplasty (DSAEK) graft injector and to compare complications, visual acuity, and endothelial cell loss with a forceps technique. Methods: An Institutional Review Board–approved, interventional, nonrandomized, consecutive case series analysis of 175 eyes undergoing DSAEK for Fuchs dystrophy and bullous keratopathy. The injector arm is prospective, and the forceps arm is retrospective. Seventy grafts were performed with a DSAEK graft injector, and 105 grafts were performed using a small-incision forceps technique. Preoperative and postoperative visual acuities at 3 and 6 months, 6-month endothelial cell counts, and complications, including graft dislocation, failure, and rejection, were recorded. Fifty-seven of 232 eyes met exclusion criteria for previous incisional corneal or glaucoma surgery. Results: There were 4 eyes (5.7%) in the injector group and 29 eyes (27.6%) in the forceps group that required a re-bubble procedure because of graft detachment. One graft (1.4%) failed in the injector group and 7 grafts (6.5%) failed in the forceps group. Excluding eyes with other ocular comorbidities (43), in the injector group 74% were 20/40 or better at 6 months and 100% were 20/60 or better. In the forceps group, 72% were 20/40 or better at 6 months and 98% were 20/60 or better. Six-month postoperative endothelial cell counts were available for 84 (46 injector and 38 forceps) eyes, with an average cell loss of 28.3% in the injector group and 44.1% in the forceps group. Conclusions: DSAEK is an effective treatment of endothelial dysfunction. Surgical technique is important to limit endothelial cell loss and prevent complications, such as graft dislocation. The injector device has several advantages over the trifold forceps technique, including decreased endothelial cell loss, graft dislocation rate, and graft failure rate, and it reduces the DSAEK learning curve. DSAEK graft injectors likely will have a role in the future of endothelial keratoplasty.

Three-millimeter incision descemet stripping endothelial keratoplasty using sodium hyaluronate (healon): a survey of 105 eyes.

Purpose: To report a Descemet stripping automated endothelial keratoplasty (DSAEK) insertion technique using sodium hyaluronate (Healon) and describe complication rates, visual acuity, and endothelial cell counts. Methods: A retrospective analysis of 105 eyes in 91 patients undergoing DSAEK. Ninety-three eyes had Fuchs endothelial dystrophy, 11 had bullous keratopathy, and 1 had iridocorneal endothelial (ICE) syndrome. We noted pre- and postoperative visual acuity at 3 and 6 months, endothelial cell counts, and complications, including graft detachment rates. Thirty-six of 141 eyes met exclusion criteria of prior incisional corneal, glaucoma, or retinal surgery. Results: Because of graft detachment, 29 of 105 eyes (28%) required a re-bubble procedure at day 1 or week 1. Five of 105 grafts (4.8%) failed. Of note, in the last 35 cases, there were no graft failures and 5 detachments (14%). Twenty-eight percent of patients were 20/40 or better preoperatively compared with 49% at 3 months and 52% at 6 months. Excluding eyes with other ocular comorbidities (34), 62% were 20/40 or better at 3 months and 72% were 20/40 or better at 6 months. Postoperative endothelial cell counts were available for 52 eyes with an average cell loss of 44% at an average of 9.4 months. Conclusions: DSAEK is an effective treatment for endothelial dysfunction, but the learning curve is steep. Anterior chamber stability, graft positioning, and small incision insertion are advantages to our technique. Disadvantages include a relatively high endothelial loss and dislocation rate. Minimizing endothelial cell loss and graft dislocation continue to be important goals for successful DSAEK.