Long-Term Results of Phototherapeutic Keratectomy Versus Mechanical Epithelial Removal Followed by Corneal Collagen Cross-Linking for Keratoconus.

PURPOSE: To compare the long-term visual outcomes of patients with keratoconus treated with either phototherapeutic keratectomy (PTK) or mechanical epithelial removal before corneal collagen cross-linking (CXL) at 1, 3, 6, and 12 months postoperatively. METHODS: CXL was performed by 1 of 3 surgeons (K.B., W.B.J., or G.M.). Seventeen eyes underwent mechanical epithelial removal before CXL and were consecutively selected after being matched with the 17 eyes in the PTK group for the variables of procedure date, average keratometry, and pachymetry. All cones were central. Manifest refraction spherical equivalent, sphere, cylinder, corrected distance visual acuity (CDVA), and pachymetry were measured and compared preoperatively and in follow-up. RESULTS: The mean CDVA change in the PTK group at 12 months postoperatively was statistically different from the mean CDVA change in the mechanical group at 12 months postoperatively (P = 0.031). The PTK group had significantly better outcomes in visual acuity 12 months postoperatively than did the mechanical group (P > 0.05). The mean number of lines of improvement in the PTK and mechanical groups were 2.30 ± 0.96 and 0.00 ± 0.33 lines, respectively (P = 0.0036). The mean change between the preoperative and 12 months postoperative manifest refraction spherical equivalent for the PTK and mechanical groups were 0.78 ± 0.65 and 0.17 ± 0.65, respectively (P > 0.05). CONCLUSIONS: PTK CXL resulted in better visual outcomes in comparison with mechanical epithelial removal CXL 1 year after treatment.

Secondary corneal amyloidosis after perforating corneal trauma: A series of 5 cases and review of the literature.

We retrospectively reviewed the clinical and surgical histories of 5 patients with traumatic secondary corneal amyloidosis, a relatively rare sequela of nonsurgical and surgical perforating corneal trauma. Four had history of nonsurgical trauma, and 1 had surgical trauma to the cornea. Three specimens were obtained by penetrating keratoplasties and 2 by excision of the cornea during evisceration of the ocular contents. All the corneal specimens showed full-thickness scars of a prior perforating wound with congophilic amyloid deposits that exhibited apple-green birefringence under polarized light and dichroism. All cases had variable degrees of predominantly chronic nongranulomatous inflammation. Ultrastructural examination in 1 patient disclosed 8-nm diameter fibrils in disarray, consistent with amyloid. Amyloid P immunostaining was positive in all 3 patients tested for this protein.

Long-term visual and refractive outcomes following surface ablation techniques in a large population for myopia correction.

PURPOSE: To evaluate the visual and refractive outcome for four wavefront-guided surface ablation (WGSA) techniques (LASEK, LASEK flap-off [LASEK FO], Epi-LASIK, and Epi-LASIK flap-off [Epi-LASIK FO]) in a large myopic population. METHODS: This retrospective review included 1000 myopic eyes (spherical equivalent [SE] -1.0 to -8.0 diopters [D]) treated with WGSA (VISX STAR S4 with IR) using four different epithelial management techniques. Flaps were either retained (163 Epi-LASIK, 361 LASEK) or discarded (277 Epi-LASIK FO, 199 LASEK FO). Eyes in each group were stratified to either low, mild, moderate, or high myopia based on preoperative SE. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), predictability, lines lost, and haze were compared at 3, 6, and 12 months. RESULTS: At 1 year, UDVA and CDVA of ≥20/20 and 20/15 were comparable across the four procedure groups and within each subgroup of myopia. Predictability was less than or equal to ±0.5 D of intended correction in 96% to 99% of eyes. LASEK FO and Epi-LASIK FO outperformed the EPI-LASIK in achieved MRSE, especially in the high myopia category (-0.012, 0.040, and -0.27 D, respectively, P < 0.05). No eyes lost more than one line of CDVA; and 50% to 60% of eyes in each group gained one or more lines. No significant haze was recorded in any group. There was no statistically significant difference between groups in the preoperative MRSE and efficacy indices except for LASEK FO. CONCLUSIONS: At 1 year, there was no statistically significant difference in visual outcomes between techniques for any degree of myopia. However, the MRSE achieved with LASEK FO and Epi-LASIK FO were closer to emmetropia.

Phototherapeutic keratectomy versus mechanical epithelial removal followed by corneal collagen crosslinking for keratoconus.

OBJECTIVE: To compare the visual outcomes of patients with keratoconus treated with either phototherapeutic keratectomy (PTK) or mechanical epithelial removal prior to corneal collagen crosslinking (CXL). DESIGN: Comparative study. PARTICIPANTS: The records of 34 patients (34 eyes) who had PTK (17 eyes) or mechanical (17 eyes) epithelial removal prior to CXL for keratoconus were reviewed retrospectively. METHODS: CXL was performed by 1 of 3 surgeons (G.M., W.B.J., or K.B.). Of the eyes, 17 had undergone mechanical epithelial removal prior to CXL and were consecutively selected, after matching with the 17 eyes in the PTK group, for the variables of procedure date, average keratometry, and pachymetry. All eyes had central cones. Manifest refraction spherical equivalent, sphere, cylinder, best-corrected distance visual acuity, and pachymetry were measured and compared preoperatively and in follow-up. RESULTS: The mean change between the pre- and postoperative manifest refraction spherical equivalent for the PTK and mechanical groups was 1.68 ± 0.80 and 0.26 ± 0.90, respectively (p < 0.05). The mean change between pre- and postoperative cylinder for the PTK and mechanical groups was 0.53 ± 0.28 and 0 ± 0.18, respectively (p < 0.05). The mean number of lines of improvement in the PTK and mechanical groups were 0.33 ± 0.82 and -0.58 ± 0.45 lines, respectively (p > 0.05). CONCLUSIONS: Early results suggest that CXL with laser epithelial removal is superior to CXL with mechanical epithelial removal because it reduces refractive error in qualified patients. Although not statistically significant, there was also a trend for PTK CXL patients to have better visual outcomes.

Myxomatous corneal degeneration: a clinicopathological study of six cases and a review of the literature.

Thirteen cases with myxomatous changes of the corneal stroma have been reported to date. We report six additional cases with clinical, histopathological, and immunohistochemical data. The clinical appearance is most often a gelatinous, whitish elevation with insidious onset. Histopathologically, there are inconspicuous spindle- and stellate-shaped cells in a loose, myxoid matrix. The typical location is in the anterior cornea beneath the epithelium, with varying degrees of extension into the stroma. Vimentin and smooth-muscle actin immunohistochemical stains are characteristically positive, and staining occasionally may be seen with muscle-specific actin, whereas CD34 staining usually is negative. In most cases, myxomatous changes are a degenerative process involving transformation of stromal keratocytes into cells with prominent secretory activity and myofibroblastic differentiation. Most occur in corneas with a history of ocular disease or trauma that disrupts Bowman's layer. We suggest labelling lesions with these features as "myxomatous corneal degeneration." So-called "primary corneal myxomas" also exist where there is no significant history. It remains unclear whether the myxomatous changes in such lesions are neoplastic or degenerative. Myxomatous corneal changes are likely under-recognized and under-diagnosed.

Aspheric wavefront-guided LASIK to treat hyperopic presbyopia: 12-month results with the VISX platform.

PURPOSE: To evaluate an aspheric ablation profile to improve near vision in presbyopic patients with hyperopia and to outline the key factors of success. METHODS: A prospective, nonrandomized, clinical trial of 66 eyes of 33 hyperopic patients who underwent customized bilateral refractive surgery, which included an aspheric presbyopia treatment shape and wavefront-driven hyperopic treatment, was studied. Surgeries were performed using the VISX STAR S4 or STAR S4 IR excimer laser system (Abbott Medical Optics). Mean preoperative refractive error was +1.77 ± 0.56 diopters (D) sphere (range: 0.75 to 3.50 D) with 0.41 ± 0.34 D cylinder (range: 0.00 to 1.50 D). All patients received full distance refractive correction. No patients received monovision or were intentionally left with residual myopia. Patient satisfaction results were evaluated using a questionnaire with a 5-point scale. RESULTS: Sixty eyes completed 6-month and 50 eyes completed 12-month postoperative follow-up. At 6 months, mean corrected distance visual acuity (CDVA) was 20/20±1 line (range: 20/25 to 20/10). Mean gain in distance-corrected near visual acuity (DCNVA) was 2.7 ± 1.7 lines with a maximum of 6 lines of near. Spectacle dependence for tasks, such as reading and computer use, was reduced. At 12 months, 100% of patients had achieved binocular simultaneous uncorrected vision of 20/25 or better and J3. Refraction was stable over 12 months. Contrast sensitivity reduction was clinically insignificant (1 step or 0.15 logCS). Negative spherical aberration highly correlated with postoperative improvement of DCNVA. Patients who had a larger amount of preoperative hyperopia or a greater decrease of preoperative DCNVA were more likely to have overall satisfaction. CONCLUSIONS: The aspheric ablation designed to expand near functional vision was effective and stable over 12 months. The wavefront-customized hyperopic treatment significantly reduced spectacle dependence.

Acanthamoeba keratitis: persistent organisms without inflammation after 1 year of topical chlorhexidine.

PURPOSE: To report a non-contact lens wearer with persistent Acanthamoeba organisms in the cornea after being treated with medical therapy that included topical chlorhexidine as 1 agent for 1 year. METHODS: A 53-year-old man with Acanthamoeba keratitis was treated with medical therapy for >1 year, followed by a penetrating keratoplasty. RESULTS: Histopathologic examination of the keratoplasty specimen revealed viable-appearing Acanthamoeba cysts and trophozoites within the deep corneal stroma in a focus of corneal scarring. CONCLUSIONS: The use of chlorhexidine as 1 agent in the medical management of Acanthamoeba keratitis may not eradicate the organisms.

Corneal myxoma arising in a patient with repeated phototherapeutic keratectomies.

PURPOSE: We report the clinical and pathologic findings of a corneal myxoma that was diagnosed in a cornea that had undergone phototherapeutic keratectomy (PTK). METHODS: A corneal myxoma was identified in a full-thickness keratoplasty specimen obtained from a 51-year-old man with a history of a forceps injury to his right eye at birth. The patient had presented with corneal edema and bullous keratopathy, which was treated on 3 occasions with PTK, resulting in progressive, persistent milky-white clouding of the cornea. This represents the eighth case of corneal myxoma in the reviewed literature and the first described after PTK. Thorough histopathologic and ultrastructural analyses were conducted. RESULTS: The histochemical, immunohistochemical, and electron microscopic findings were consistent with previously reported corneal myxomas. Most of the reported myxomas arising in the cornea presented with a history of prior corneal disease or injury and showed absence or disruption of Bowman layer histopathologically, as was found in our patient. CONCLUSION: The pathogenesis of corneal myxomas involves a reactive process that requires an antecedent affliction, in contrast to the neoplastic mesenchymal histogenesis of myxomas characterized in other parts of the body.