Trends in contact lens-related corneal ulcers at a tertiary referral center.

PURPOSE: To evaluate the changes and trends in the number and characteristics of contact lens-related ulcers (CLRUs) and to compare the results with those of previously published series at our institution. METHODS: Medical records of all patients diagnosed with presumed bacterial corneal ulcers seen at the Cornea Service, Wills Eye Institute, between January 1, 2004, and December 31, 2007, were retrospectively reviewed. RESULTS: Five hundred seven corneal ulcers were identified. Of these, 223 (43.9%) were contact lens (CL) related and 284 (56.1%) were not CL related. The proportion of CLRU showed a significant increase over time (P = 0.003), with significantly greater percentage of CLRU in 2006 and 2007 compared with 2004 (P = 0.004 and P = 0.005, respectively). One hundred thirty-one (58.7%) of the 223 CLRU patients were men. Many CLRUs were vision threatening, with 45.7% (92 of 201) more than 4 mm in size, 36.3% (81 of 223) associated with hypopyon, and 46.4% (103 of 222) central or paracentral in location. Pseudomonas aeruginosa was the most frequent agent isolated in CLRUs, found in 75 (63.0%) of 119 positive cultures. Soft daily-wear frequent replacement lenses were the most common lenses associated with corneal ulcers and were used in 68 (33.5%) of 203 cases. There was a history of overnight wear of CLs in more than half of the cases (121 of 223, 54.3%). Of these, 21 (9.4%) were not approved for overnight wear. CONCLUSIONS: There was a significant increase in the number of cases of presumed bacterial keratitis associated with soft CL wear over the study period from 2004 to 2007 at our institution. The significant increase in CLRU noted from 1996 to 1999 to 1999 to 2002 reported previously seems to have continued between 2004 and 2007.

Bilateral circumferential macular folds in inflicted childhood neurotrauma.

PURPOSE: To report an infant with inflicted neurotrauma who exhibited bilateral circumferential macular folds. METHODS: Bedside ophthalmic examination and fundus photography using RetCam-II (Clarity Medical Systems, Pleasanton, CA). RESULTS: Both pupils were miotic and nonreactive. External and anterior segments showed no abnormality. The fundus showed bilateral diffuse multilaminar retinal, subhyaloid, and vitreous hemorrhages. Distinctive macular folds were noted bilaterally. CONCLUSION: Circumferential macular folds are most commonly found in abused infants, although it has been suggested that they may be associated with Terson syndrome and severe crush injury.

Intravitreal injection of tissue plasminogen activator as treatment for an occluded pars plana glaucoma tube.

Implanting glaucoma tubes through the pars plana in the setting of a corneal transplant is becoming more common, and there are unique problems associated with such a procedure. A 42-year-old man with multiple previous eye surgeries presented with a nonfunctioning pars plana glaucoma tube. There was no view to the tube tip, but it was presumed to be clogged with fibrin. Intravitreal tissue plasminogen activator (tPA) was injected through the pars plana which resulted in intraocular pressure control without further surgery. This new application of intravitreal tPA has not been reported previously. Future research should investigate the optimal effective and safe dose of intravitreal tPA injection to relieve such occlusions.

Initial studies using aliphatic beta-nitro alcohols for therapeutic corneal cross-linking.

PURPOSE: Corneal collagen cross-linking through UVA-riboflavin photochemistry (UVAR) has been shown to be an effective treatment for keratoconus and related keratectasias. In recent studies using sclera, the authors observed that short-chain aliphatic beta-nitro alcohols can cross-link collagenous tissue under physiologic conditions. Thus, this study was undertaken to evaluate these agents as potential pharmacologic alternatives to UVAR. METHODS: Porcine corneal strips (8 x 4 mm) and corneoscleral complexes were cross-linked using 1 to 100 mM 2-nitroethanol (2ne), 2-nitro-1-propanol (2nprop), and 3-nitro-2-pentanol (3n2pent) at pH 7.4, 34 degrees C. Cross-linking by UVAR was carried out for comparison. Thermal shrinkage temperature analysis was used to evaluate cross-linking effects, and changes in corneal light transmission were determined with a fiber-optic spectrophotometer. RESULTS: At 10 and 100 mM for 96 hours, initial shrinkage temperature (T(i)) was shifted by 3.3 degrees C (P < 0.001) and 9.8 degrees C (P < 0.001) for 2ne, 2.9 degrees C (P = 0.008) and 4.9 degrees C (P < 0.001) for 2nprop, and 3.8 degrees C (P = 0.003) and 4.9 degrees C (P < 0.001) for 3n2pent. Reacting at 1 mM through daily exchange of fluid over 7 days shifted T(i) by 3.8 degrees C (P < 0.001), 4.4 degrees C (P = 0.002), and 3.2 degrees C (P = 0.005), for 2ne, 2nprop, and 3n2pent, respectively. These shifts were greater than cross-linking using UVAR (T(i) = 1.9 degrees C; P = 0.012). In the blue light region (400-500 nm), transmission was decreased by 5.6% (P = 0.003), 2.1% (P = 0.260), and 0% (P = 0.428) for 2ne, 2nprop, and 3n2pent, respectively. CONCLUSIONS: beta-Nitro alcohols can induce corneal cross-linking in vitro better than the UVAR technique and can induce negligible effects on light transmission. These early results suggest that such compounds could be used as topical stiffening agents for keratoconus and related disorders.

Aliphatic beta-nitro alcohols for non-enzymatic collagen cross-linking of scleral tissue.

The success of riboflavin photochemical cross-linking of the cornea in treating keratoconus and post-surgical keratectasia has prompted interest in cross-linking scleral tissue with a potential application to stabilize myopic progression. Applying an UVA light source to the sclera is difficult, particularly in the posterior region. An alternate pharmacologic approach to scleral cross-linking may be possible. The present study was undertaken in order to identify nitrite related compounds capable of inducing scleral tissue cross-linking and to gain information regarding the possible chemical mechanisms involved. 8x4 mm strips of porcine and human sclera were incubated in various concentrations of nitrite related agents (1-100mM) at 37 degrees C. pH 7.4 was used for all experiments except those involving NaNO(2). Following a 24-96 h incubation period, the samples were tested for cross-linking effects using thermal shrinkage temperature (T(s)) analysis. Several compounds were studied including NaNO(2), 2-nitroethanol, 2-nitro-1-propanol, 3-nitro-2-pentanol, 2-nitrophenol, 2-nitroethane, 2-aminoethanol, isopentyl nitrite, DPTA/NO, DETA/NO, and urea, a nitrous acid trap. The results indicate that short chain aliphatic beta-nitro alcohols (2-nitroethanol, 2-nitro-1-propanol, and 3-nitro-2-pentanol) are particularly effective cross-linking agents at pH 7.4, showing both time and concentration dependent effects. Furthermore, nitrosation does not appear to induce tissue cross-linking. In conclusion, aliphatic beta-nitro alcohols can cross-link scleral tissue at physiologic pH and temperature. Since beta-nitro alcohols are known to have reasonable toxicity profiles, these agents could find utility as pharmacologic cross-linking agents for scleral thinning disease.

Evaluating central corneal thickness measurements with noncontact optical low-coherence reflectometry and contact ultrasound pachymetry.

PURPOSE: To compare the central corneal thickness (CCT) measurements obtained with noncontact optical low-coherence reflectometry (OLCR) and ultrasound (US) pachymetry. DESIGN: Prospective, comparative observational study. METHODS: Three sequential ultrasonic measurements and a set of five OLCR scans of 52 eyes of 26 healthy subjects were recorded. Noncontact measurement was repeated five minutes after anesthetic drop instillation. RESULTS: Mean CCT values for noncontact OLCR and US pachymetry were 544.03 microm and 548.66 microm, respectively, with mean SDs of 0.97 microm and 4.63 microm, respectively. Noncontact OLCR measured on average 4.64 microm less than US pachymetry (95% confidence interval -7.56 to -1.72; P = .003). The OLCR measured 1.68 microm less than US pachymetry in the thinner cornea group (< or =548.7 microm, n = 24) and 7.48 mum less in the thicker group (n = 25). This difference was statistically significant (P = .04). CONCLUSIONS: There was agreement between the two pachymetric measurements. Noncontact OLCR appeared to measure slightly smaller than US pachymetry.

Accommodative spasm after laser-assisted in situ keratomileusis (LASIK).

PURPOSE: To report a case of accommodative spasm following laser-assisted in situ keratomileusis (LASIK). DESIGN: Observational case report. METHODS: Ophthalmic examination including manifest and cycloplegic refraction to assist in diagnosis. RESULTS: Two months following LASIK surgery, a 41-year-old healthy woman complained of intolerable headaches that had interfered with her daily activities. The patient sought medical consultation, and an MRI of the brain was normal. Best-corrected visual acuity (BCVA) was 20/20 and 20/25 with manifest refraction of -2.25 -0.50 x 170 and plano in the right and the left eye, respectively. Cycloplegic refraction was plano in the right and +0.75 sphere in the left eye, and she was corrected to 20/20 bilaterally. After being treated with cyclopentolate 1% one drop at bedtime to each eye for approximately six weeks, the headache completely resolved. CONCLUSIONS: Accommodative spasm should be considered in patients undergoing LASIK surgery complicated with fluctuating refraction of uncertain causes.

The effect of lubricant eye drops on ocular wavefront aberrations.

PURPOSE: To study the effect of lubricant eye drop instillation on ocular wavefront aberrations. METHODS: The wavefront aberrations of the entire optical path of 30 eyes of 15 patients before and following instillation of lubricant eye drops (Bion Tears; Alcon Laboratories Inc, Ft Worth, Tex) were obtained over a 6-mm pupil using a Hartmann-Shack wavefront sensor (WaveScan; VISX Inc, Santa Clara, Calif). Additional computation of root-mean-square (RMS) errors of higher order aberrations from third to sixth order were done using Zernike Tool Software (VISX Inc). Main outcome measures include the mean changes of total higher order aberrations RMS, higher order aberrations, and point spread function (PSF) of the higher order aberrations. RESULTS: The mean changes of total higher order aberrations following instillation of lubricant eye drops on the right eyes were -0.07 microm (95% confidence interval [CI], -0.11 to -0.03) and -0.03 microm on the left eyes (95% CI, -0.07 to 0.01). Significant mean changes were noted for coma and trefoil aberrations with a magnitude of -0.08 microm (95% CI, -0.12 to -0.03) and -0.09 (95% CI, -0.13 to -0.05), respectively, as well as a mean change of the PSF of the higher order aberrations (-0.05 diopters, 95% CI, -0.08 to -0.02) on the right eyes. Although no significant changes in these parameters were demonstrated on the left eyes, a similar trend of changes was observed. CONCLUSIONS: Ocular wavefront aberrations may change following eye drop instillation as measured objectively by the WaveScan system. This effect should be taken into consideration in the assessment of patients for wavefront-guided laser vision correction procedures.

Epithelial ingrowth under a laser in situ keratomileusis flap after phacoemulsification.

A 47-year-old man was referred to us for management of a cataract in the left eye. The patient had an ocular history of high myopia with anisometropia, amblyopia in the left eye, and stable myopic lattice degeneration in both eyes. The patient had successful bilateral laser in situ keratomileusis 3 years before and multiple retinal surgeries for treatment of a rhegmatogenous retinal detachment associated with a giant retinal tear in the temporal region of the retina with subsequent proliferative vitreoretinopathy. Phacoemulsification was performed uneventfully. A single interrupted 10-0 nylon suture was placed in the temporal clear corneal wound and removed 7 weeks postoperatively. One month later, slitlamp examination revealed a 1.5 mm tongue-like area of epithelial ingrowth under the corneal flap. The epithelial cells seemed to enter the flap-stroma interface through the previously placed suture tract and advanced centrally.

Corneal edema resolution after "descemetorhexis".

A 79-year-old woman had left eye phacoemulsification complicated by inadvertent excision of Descemet's membrane (DM). One day postoperatively, the visual acuity was counting fingers with diffuse corneal edema. The patient was treated medically, with gradual resolution of the corneal edema over a 6-month period. The torn edge of DM could be visualized as the edema cleared, and no endothelial cell count could be obtained centrally. Approximately 1 year postoperatively, the central endothelial cell count was 2114 cells/mm(2) in the right eye and 827 cells/mm(2) in the left eye. The decreased cell count, increased polymegethism, and pleomorphism suggested that endothelial cells migrated to cover the stromal surface area in the absence of DM.

Cataract surgery results after pars plana vitrectomy.

Continuous refinements in vitreoretinal surgical techniques and an increasing number of posterior segment disorders are being successfully managed with pars plana vitrectomy (PPV). This has resulted in an increase in the number of vitrectomized eyes seen by cataract surgeons. Cataract surgery in previously vitrectomized eyes has been reported to be more challenging than in eyes without previous vitrectomy. Special considerations and precautions are often required before, during, and after the surgery to successfully address these challenges. Several studies have reported that phacoemulsification with intraocular lens implantation after PPV is a relatively safe procedure that can improve visual acuity and quality of life. The extent of visual improvement may be limited only by retinal comorbidity.

Tegaderm transparent dressing (3M) for the treatment of chronic exposure keratopathy.

We report an effective alternative treatment of profound chronic exposure keratopathy in a proptotic eye due to intraorbital extension of basal cell carcinoma. The corneal surface gradually reepithelialized in a 6-week period after the first application of Tegaderm transparent dressing (3M, St. Paul, MN, U.S.A.) with instillation of antibiotic ointment on the ocular surface. The patient has been comfortable with an intact epithelial surface, a vascularized cornea, and nonirritated surrounding skin after changing the Tegaderm dressing daily for 15 months. There was no evidence of recurrent corneal ulceration or infiltrations. We conclude that Tegaderm represents a useful treatment of exposure keratopathy due to chronic proptosis.