Corneal collagen crosslinking in patients treated with dextran versus isotonic hydroxypropyl methylcellulose (HPMC) riboflavin solution: a retrospective analysis.

BACKGROUND: Corneal collagen crosslinking (CXL) is a widely used treatment for halting the progression of keratoconus. Although initial studies of CXL were performed with a riboflavin solution containing dextran, recent protocols for CXL have indicated the use of a riboflavin solution containing isotonic hydroxypropyl methylcellulose (HPMC). This study was performed to investigate differences in visual outcomes and Scheimpflug (Pentacam) analysis in patients who have undergone epithelium-off CXL with riboflavin solution containing either 20% dextran versus 1.1% HPMC. METHODS: All patients in this non-randomized, non-masked, retrospective cohort analysis were treated at Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA. Thirty-seven eyes of 33 patients were crosslinked with a dextran solution and 19 eyes of 19 patients crosslinked with an isotonic HPMC solution, both using an epithelium-off 30-min, 3 mW/cm2 protocol. All patients had a diagnosis of keratoconus or post-refractive surgery ectasia. Best spectacle corrected visual acuity (BSCVA) and Pentacam parameters were compared at all follow up visits (1, 6, 12, and 24 months). Differences between groups treated with HPMC and dextran were compared using student's t-test. Differences between treated eye and fellow eye were calculated and compared between HPMC and dextran groups using paired t-test. RESULTS: Patients treated with a dextran solution had significantly greater improvement in BSCVA at 1, 6, and 24 months (p < 0.05) compared to the isotonic HPMC-treated group. Kmax increased in both groups at 1 month; however, HPMC-treated patients had a greater increase compared to dextran-treated patients (p = 0.01). Kmax decreased in both groups at 6 and 12 months, although this finding was only significant in the HPMC-treated group at 12 months. CONCLUSIONS: Our data suggest that crosslinking with the dextran solution may result in significantly better visual outcomes (demonstrated by visual acuity) compared to the isotonic HPMC riboflavin solution. Dextran solutions may have other potential advantages intrinsic to its biochemical properties facilitating more efficient crosslinking. Further research and long-term evidence regarding the use of dextran versus HPMC riboflavin solutions in collagen crosslinking is necessary.

Correlation of Scheimpflug densitometry changes with clinical outcomes after corneal crosslinking.

PURPOSE: To characterize changes in densitometry after corneal crosslinking (CXL) and correlate it with visual outcomes. SETTING: Tertiary referral academic medical center, New York, New York, USA. DESIGN: Retrospective case series. METHODS: Patients with progressive keratoconus or post-laser in situ keratomileusis ectasia had CXL following the Dresden protocol. The corrected distance visual acuity (CDVA) and Pentacam imaging were obtained at baseline and follow-up visits. RESULTS: Fifty-seven patients were followed for a mean of 15 months (range 1 to 24 months) after CXL. The CDVA improved significantly from baseline to 6, 12, 18, and 24 months postoperatively. The change in densitometry of the mid-stromal layer, 2.0 to 6.0 mm annulus, at 6 months was correlated with the improvement in CDVA at 6, 12, and 24 months (all P < .10). The increase in densitometry of the mid-stromal layer, centermost 0.0 to 2.0 mm annulus, at 6 months was significantly associated with the decrease in maximum keratometry (K) at 6 and 12 months (both P < .05). Last, the change in densitometry at 6 months was significantly correlated with the decrease in specific higher-order aberrations (HOAs) (P < .05). CONCLUSIONS: Although the greatest and most durable post-CXL densitometry change was in the anterior layer, the degree of increased densitometry haze in the mid-stromal layer was most associated with and possibly predictive of improvement in CDVA, maximum K, and HOAs. The persistence of corneal haze at 6 months, measured by increased densitometry, might be a prognostic marker for CXL effectiveness.

Posterior Amorphous Corneal Dystrophy Associated With Keratoglobus: A Case Report.

PURPOSE: Posterior amorphous corneal dystrophy (PACD) is a rare disorder characterized by sheet-like opacification of the posterior corneal stroma, corneal thinning, and decreased corneal curvature. It is not known to be associated with progressive corneal ectasia. In this report, we examine the course of a patient with PACD who developed bilateral keratoglobus-type corneal ectasia. METHODS: The clinical history of a single patient is reviewed from birth through age 15. Visual acuity, refraction, ultrasound pachymetry, anterior segment optical coherence tomography, corneal topography, and corneal tomography are presented. RESULTS: The patient was noted to have bilateral cloudy corneas at birth. Congenital infection, metabolic disease, and glaucoma were ruled out. Anterior segment optical coherence tomography demonstrated posterior stromal opacification typical of PACD. Over time, the patient progressed from best uncorrected visual acuity of 20/20-2 OD and 20/25-3 OS to PROSE lens-corrected visual acuity of 20/30-3 OD and 20/30-3 OS. Central corneal thinness progressed from 491 to 408 µm in the right eye and from 505 to 389 µm in the left eye. Steepening in corneal axial/sagittal curvature developed in both eyes beginning inferiorly then involving the corneas diffusely. CONCLUSIONS: In this case report, we illustrate progressive corneal ectasia in a patient with PACD. Although both conditions may represent changes in the structure and integrity of corneal collagen, whether an association exists between the 2 conditions is unknown.

Ocular Manifestations of Inherited Phospholipase-Cγ2-Associated Antibody Deficiency and Immune Dysregulation.

PURPOSE: To report the ocular manifestations of phospholipase-Cγ2-associated antibody deficiency and immune dysregulation (PLAID). METHODS: Case report and literature review. RESULTS: A 21-year-old woman diagnosed with PLAID was referred for evaluation of repeated episodes of ocular inflammation resulting in bilateral peripheral corneal pannus with episcleritis and corneal scarring accompanied by systemic manifestations including epidermolysis bullosa and interstitial lung disease. Systemic immunosuppression with corticosteroids and interleukin-1 (IL-1) receptor antagonist (anakinra) was supplemented with topical anakinra to avoid systemic side effects, which resulted in partial improvement of the ocular symptoms. Oral prednisone was restarted to treat active lesions during bouts of inflammation. CONCLUSIONS: Ocular PLAID is a bilateral chronic or recurrent inflammatory disease of the ocular surface leading to severe and early cicatricial ocular surface and corneal involvement because of high IL-1 production. Management of PLAID may require both topical and systemic immunomodulatory treatments, potentially including targeted local anti-IL-1 therapy.

Night vision disturbances after corneal refractive surgery.

A certain percentage of patients complain of "glare" at night after undergoing a refractive surgical procedure. When patients speak of glare they are, technically, describing a decrease in quality of vision secondary to glare disability, decreased contrast sensitivity, and image degradations, or more succinctly, "night vision disturbances." The definitions, differences, and methods of measurement of such vision disturbances after refractive surgery are described in our article. In most cases of corneal refractive surgery, there is a significant increase in vision disturbances immediately following the procedure. The majority of patients improve between 6 months to 1 year post-surgery. The relation between pupil size and the optical clear zone are most important in minimizing these disturbances in RK. In PRK and LASIK, pupil size and the ablation diameter size and location are the major factors involved. Treatment options for disabling glare are also discussed. With the exponential increase of patients having refractive surgery, the increase of patients complaining of scotopic or mesopic vision disturbances may become a major public health issue in the near future. Currently, however, there are no gold-standard clinical tests available to measure glare disability, contrast sensitivity, or image degradations. Standardization is essential for objective measurement and follow-up to further our understanding of the effects of these surgeries on the optical system and thus, hopefully, allow for modification of our techniques to decrease or eliminate post-refractive vision disturbances.

Confocal microscopy in Meretoja syndrome.

PURPOSE: To study the correlation between severity of clinical systemic symptoms and the degree of stromal haze and visibility of epithelial and stromal nerves on scanning slit confocal microscopy examination in Meretoja syndrome. METHODS: Three patients with Meretoja syndrome were examined by slit-lamp microscopy and scanning slit confocal microscopy. RESULTS: Increased symptoms and abnormal slit-lamp findings correlated positively with confocal microscopic stromal haze intensity and inversely with visibility of epithelial and stromal nerves on confocal examination. A prominent deposit, presumably amyloid, was observed contiguous to a stromal nerve of an affected cornea. In a severely affected cornea, no stromal or epithelial nerves were seen. CONCLUSION: The results of this study suggest that Meretoja syndrome causes corneal nerve damage and eventual degeneration that correlates with the degree of clinical involvement.

Corneal graft survival and intraocular pressure control in coexisting penetrating keratoplasty and pars plana Ahmed Glaucoma Valves.

PURPOSE: To evaluate corneal graft survival and intraocular pressure (IOP) control after penetrating keratoplasty (PK) and pars plana Ahmed Glaucoma Valve (AGV) implantation among patients with coexisting glaucoma and corneal disease. METHODS: Retrospective chart review at an institution of 25 eyes (24 patients) that received PK and pars plana AGV. RESULTS: The mean postoperative follow-up was 23 months (range, 2-106 months). Survival of the grafts was 89% (16 of 18 eyes) at 1 year and 63% (5 of 8) at 2 years. IOP control was 78% (15 of 19) at 1 year and 44% (4 of 9) at 2 years. By Kaplan-Meier analysis, the 50% probability of sustained graft clarity occurred at 28 months and that of sustained IOP control at 24 months. By last follow-up, best-corrected visual acuity had improved by at least 1 line in 52% (13 of 25) of eyes compared with preoperative values. Preoperative factors, including peripheral anterior synechiae, were not found to be associated with graft survival, IOP control, or visual acuity at 1 year. CONCLUSION: Pars plana AGV can successfully control IOP in PK patients in the short and intermediate terms, but graft clarity and IOP control diminish over time. Graft decompensation, when it did occur, likely reflects the associated ocular morbidity and clinical complexity of this circumscribed cohort of eyes.

Penetrating keratoplasty in active Acanthamoeba keratitis.

PURPOSE: To report the results of penetrating keratoplasty (PK) in active Acanthamoeba keratitis (AK). METHODS: Nine patients with deep stromal infiltrates because of AK were treated with intensive antiamoebic medical therapy followed by PK during the acute infectious phase because of poor clinical response or poor compliance. Antiamoebic therapy was tapered after PK. RESULTS: Visual acuity ranged from 20/15 to 20/50 after an average of 17 months after PK with no signs of recurrences. Patients had rapid resolution of symptoms. CONCLUSION: PK is a viable option for active AK not responding to maximum medical treatment.