Alessandro Abbouda

Corneal cross linking and infectious keratitis: a systematic review with a meta-analysis of reported cases

BackgroundCollagen cross linking (CXL) of the cornea has been developed recently as a new treatment for multidrug-resistant infectious keratitis. The aim of this study is to summarize the previously published data and evaluate the effectiveness of this treatment.ResultsThe search identified 12 articles. The number of eyes was 104. The infectious keratitis was associated with bacteria in 58 eyes (57f%): Gram-positive bacteria in 44 (43%; 4 of which were infected with Mycobacterium (3.6%)) and Gram-negative bacteria in 14 eyes (13%), fungus in 13 eyes (12%), and Acanthamoeba in 7 eyes (7%). In 26 eyes (25%), the microbiological culture was negative or not performed. The mean time of re-epithelization after CXL was 20.7±28.1 days (minimum of 3, maximum of 145). Sixteen eyes underwent deep or lamellar keratoplasty. The pooled analysis suggested that CXL has a favorable effect on the block of corneal melting in 85% (95%; CI 0.77, 0.91) of eyes.ConclusionAlthough randomized controlled trials are needed, the available evidence supports the use of CXL in the treatment of infectious keratitis.

Removability of a Small Aperture Intracorneal Inlay for Presbyopia Correction

PURPOSE To evaluate the safety of the corneal inlay removal procedure and the reversibility of visual acuities, corneal topography, and corneal biomicroscopy changes in a series of cases. METHODS Ten cases implanted with one of three versions of the AcuFocus Kamra Inlay (ACI 7000, 7000T, and 7000PDT; AcuFocus, Inc., Irvine, CA) were followed for a minimum of 6 months after corneal inlay removal. RESULTS The reason for removal was related to subjective dissatisfaction with visual symptoms (8 of 10 patients) such as night glare, photophobia, starburst, blurry vision, and halos. One case of removal was related to inadvertent thin flap and the final case was related to insufficient near vision. Mean uncorrected distance visual acuity (UDVA) and uncorrected near visual acuity (UNVA) was 0 ± 0.1 logMAR (Snellen 20/20) and 0.5 ± 0.2 logMAR (Snellen 20/40), respectively, preoperatively and 0.1 ± 0.1 logMAR (Snellen 20/25) and 0.5 ± 0.1 logMAR (Snellen 20/63), respectively, 6 months after corneal inlay removal. Mean corrected distance visual acuity (CDVA) and corrected near visual acuity (CNVA) was 0 ± 0.1 logMAR (Snellen 20/20) and 0 ± 0.1 logMAR (Snellen 20/20), respectively, preoperatively and 0 ± 0.1 logMAR (Snellen 20/20) and 0.1 ± 0.1 logMAR (Snellen 20/25), respectively, 6 months after corneal inlay removal. Mean root mean square (RMS) higher-order aberration (HOA) was 0.50 ± 0.12 (range: 0.30 to 0.70) preoperatively and 0.69 ± 0.14 (range: 0.48 to 0.95) 6 months after corneal inlay removal (P < .8). Weak positive correlation was found between Δt Implant-Removal (Δt I-R), RMS spherical, coma, and HOA at 6 months (Δt I-R vs RMS spherical was r = 0.2, r(2) = 0.5, P < .7; Δt I-R vs RMS coma was r = 0.8, r(2) = 0.6, P < .3; and Δt I-R vs HOA r = 0.8; r(2) = 0.6, P < .9). CONCLUSION This study suggests that after removal of the corneal inlay, corneal topography and corneal aberrometry are not permanently affected. In more than 60% of patients, CNVA, CDVA, UNVA, and UDVA were similar to the preoperative value.

Laser in situ keratomileusis for −6.00 to −18.00 diopters of myopia and up to −5.00 diopters of astigmatism: 15-year follow-up

Purpose To evaluate the long‐term outcomes of laser in situ keratomileusis (LASIK) for high myopia with or without astigmatism. Setting Vissum Instituto Oftalmologico de Alicante and Miguel Hernandez University, Alicante, Spain. Design Retrospective–prospective case series. Methods Laser in situ keratomileusis was performed using the Visx 20/20 excimer laser. The minimum follow‐up was 15 years. The main outcome measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, and corneal topography. Results This study included 40 patients (40 eyes) with a mean age of 51.08 years ± 6.67 (SD) (range 41 to 60 years) with high myopia (−6.00 to −18.00 diopters [D]). At 15 years, the safety index was 1.23 and the efficacy index, 0.95. During the follow‐up, a significant increase in the dioptric power of all keratometric variables was detected (P≤.028, Friedman test), the most notable increase occurring between 3 months and 1 year (P≤.005). At 15 years, 46.15% of the eyes were within ±1.00 D of the attempted spherical equivalent and 64.10% were within ±2.00 D. The UDVA at 15 years was 20/25 or better in 43.59% of eyes and 20/40 or better in 64.10% of eyes. The postoperative CDVA was significantly better than preoperatively (P<.001). The postoperative complications were minor except in 1 eye in which ectasia occurred. Conclusions Laser in situ keratomileusis for high myopia was safe over the long term. However, significant myopic regression with time was detected. Low preoperative pachymetry and low residual stromal bed were predictors of keratometric regression. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Spectral-Domain Optical Coherence Tomography in Uveitic Macular Edema: Morphological Features and Prognostic Factors

Aim: To assess the morphological characteristics of uveitic macular edema studied with Spectralis optical coherence tomography (OCT) and to investigate the correlation between the tomographic features and visual acuity. Methods: 71 eyes of 55 patients underwent examination with Spectralis OCT (Heidelberg Engineering, Germany). Data was correlated with logMAR best-corrected visual acuity (BCVA). Results: Two morphological patterns were observed: cystoid macular edema (CME) in 69% and diffuse macular edema in 31% of eyes. BCVA was 0.2 in CME, 0.1 in diffuse edema (p = 0.008). Foveal thickness was 413.4 ± 212 µm in CME, 311.27 ± 53 µm in diffuse edema (p = 0.03). BVCA was 0.3 in eyes with serous retinal detachment (SRD), 0.2 in eyes without SRD (p = 0.02). BCVA was 0.4 in eyes with inner segment/outer segment (IS/OS) disruption, 0.1 in eyes with integrity of the IS/OS junction (p = 0.01). Conclusions: BCVA is negatively correlated with cystoid pattern, foveal thickening and SRD. Disruption of the IS/OS junction is associated with poor vision in uveitic macular edema.

Infectious Keratitis Following Corneal Crosslinking: A Systematic Review of Reported Cases: Management, Visual Outcome, and Treatment Proposed

Abstract Aim: To describe the infectious complications and the group of pathogens involved in the infection following corneal crosslinking, the visual outcome, and the treatment proposed. Methods: A Medline (National Library of Medicine, Bethesda, MD, USA) search from October 2000 to October 2013 was performed to identify all articles describing infectious keratitis following corneal crosslinking treatment. Nineteen articles were selected. Ten articles reported infectious complications of corneal crosslinking treatment were included. Nine articles were excluded, because seven described sterile keratitis, one article was in German, and one reported general complication without describing the infection complication. Results: A total number of infections reported included 10 eyes. The infectious keratitis was associated with bacteria in five eyes (50%): gram-positive bacteria in three eyes (30%) (staphylococcus epidermidis, S. aureus and streptococcus salivarius plus S. oralis, respectively) and gram-negative bacteria in two eyes (20%) (E. coli; P. aeruginosa); there was herpes virus in two eyes, fungus in two eyes (Fusarium and Microsporidia) (20%), and Acanthamoeba in one eye (10%). Conclusions: Only 10 cases of infectious keratitis following corneal crosslinking are published. The most virulent pathogens were Pseudomonas aeruginosa and Acanthamoeba. Less virulent organisms were Escherichia coli and S. epidermidis. Two cases of herpes keratitis were described, suggesting the possibility of systemic antiviral prophylaxis before corneal crosslinking treatment. The most common risk factor of infections identified was postoperative incorrect patient behavior.

Detection of subclinical keratoconus through non-contact tonometry and the use of discriminant biomechanical functions

The purpose of the present study was to develop a discriminant function departing from the biomechanical parameters provided by a non-contact tonometer (Corvis-ST, Oculus Optikgeräte, Wetzlar, Germany) to distinguish subclinical keratoconus from normal eyes. 212 eyes (120 patients) were divided in two groups: 184 healthy eyes of 92 patients aged 32.99 ± 7.85 (21-73 years) and 28 eyes of 28 patients aged 37.79 ± 14.21 (17-75 years) with subclinical keratoconus. The main outcome measures were age, sex, intraocular pressure (IOP), corneal central thickness (CCT) and other specific biomechanical parameters provided by the tonometer. Correlations between all biomechanical parameters and the rest of variables were evaluated. The biomechanical measures were corrected in IOP and CCT (since these variable are not directly related with the corneal structure and biomechanical behavior) to warrant an accurate comparison between both types of eyes. Two discriminant functions were created from the set of corrected variables. The best discriminant function created depended on three parameters: maximum Deformation Amplitude (corrected in IOP and CCT), First Applanation time (corrected in CCT) and CCT. Statistically significant differences were found between groups for this function (p=2·10(-10); Mann-Withney test). The area under the Receiving Operating Characteristic was 0.893 ± 0.028 (95% confidence interval 0.838-0.949). Sensitivity and specificity were 85.7% and 82.07% respectively. These results show that the use of biomechanical parameters provided by non-contact tonometry, previous normalization, combined with the theory of discriminant functions is a useful tool for the detection of subclinical keratoconus.

Anterior segment optical coherence tomography in evaluation of severe fungal keratitis infections treated by corneal crosslinking

Purpose Anterior segment optical coherence tomography (OCT) is a relevant diagnostic tool in the evaluation of corneal changes following corneal crosslinking (CXL) treatment in patients infected by a severe fungal corneal infection. Methods Two patients with severe fungal keratitis that was unresponsive to medical treatment were treated with CXL. Corneal melting was present in all cases. Anterior segment OCT showed the preoperative depth and extension of the infiltrate and the modification during the follow-up. Results Blockage of the melting was achieved in one patient and one patient developed a corneal perforation. Anterior segment OCT allowed control of the evolution of fungal infection and evaluation of the corneal tissue response to the CXL. It is also able to identify the extent and depth of the inflammation. This parameter seems more important than corneal pachymetry to ensure the safety of CXL procedures in infectious keratitis. Conclusions The different behavior of inflamed tissue with respect to UVA irradiance could be the main point to understand the different postoperative outcome.

Confocal microscopy evaluation of the corneal response following AcuFocus KAMRA inlay implantation.

PURPOSE To describe the corneal appearance on confocal microscopy after AcuFocus KAMRA Inlay (AcuFocus, Inc., Irvine, CA) implantation and evaluate the visual acuity compared to the confocal microscopy data. METHODS Twelve eyes of 12 patients implanted with one of three models of the AcuFocus KAMRA Inlay (ACI 7000, 7000T, and 7000PDT) were prospectively evaluated by confocal microscopy 6 months after implantation. Additionally, 4 eyes of 4 patients explanted during the follow-up period were evaluated. RESULTS Among the eyes implanted, mean epithelial thickness was 54.6 ± 22 μm. The subbasal nerve plexus was detected in 10 patients. The corneal nerves per unit area were 2.73 ± 2.1 sprouts/mm(2). The branch pattern was found in 8 patients. The mean keratocyte density value was 540 ± 210 cells/mm(2). A low grade of keratocyte activation was found in all patients. Among the eyes explanted, the mean wound healing opacity was 1,092.75 ± 1,877.35 μm/pixel. CONCLUSIONS The corneal tolerance to the KAMRA Inlay appeared to be good. The inlay modified the normal structure of the corneal layer, but it was not associated with severe complications of the eye. Keratocyte activation was the finding most associated with a negative visual outcome. Confocal microscopy can be useful to evaluate the long-term evolution of the corneal layer changes following KAMRA Inlay implantation.

Follow-Up Study of Over Three Years of Patients with Uveitis after Cataract Phacoemulsification: Outcomes and Complications

ABSTRACT Purpose: To evaluate the rate and onset of intraoperative and postoperative complications post-phacoemulsification. Methods: One hundred sixty-two eyes of 145 patients with uveitis who underwent phacoemulsification between 2006 and 2009 were identified through surgical record review. Fifty-nine eyes of 46 patients met the inclusion criteria. Hazard ratio (HR) and Kaplan-Meier survival probability were calculated for each class of uveitis. Results: Macular edema (ME) resulted to be associated to chronic postoperative inflammation (r = 0.6; p = 0.00) and mostly related to patients who presented more than one postoperative relapse/year (r = 0.2; p = 0.02). Fuchs uveitis resulted to be a risk factor for posterior capsule opacification (PCO) (HR 3.36 IC95%1.0-10.5; p = 0.03). Hypotony and elevated intraocular pressure (IOP) were detected in the anterior uveitis group (0.02 EY). Conclusion: The HR to develop ME was significantly related to chronic anterior uveitis. PCO and elevated IOP are most frequent in Fuchs uveitis. The postoperative visual acuity result was good among all the uveitis groups.

Dry Eye Syndrome in Non-Exophthalmic Graves' Disease.

ABSTRACT Background: The present study aims to assess qualitative and quantitative characteristics of tear film and corneal related impairment and to evaluate the quality of life in a cohort of non-exophthalmic Graves’ disease (GD) patients. Methods: The series comprised 50 eyes from 25 newly diagnosed GD patients with no proptosis. As control group, 56 eyes of 28 thyroid disease-free subjects were enrolled. Results: The results of Schirmer I and II, break-up time, and Oxford scheme showed a significant difference between GD and controls. By ocular surface disease index (OSDI) questionnaire, eleven (44%) GD patients had normal ocular surface, while two (8%) had mild, four (16%) had moderate, and eight (32%) had severe dry eye. The mean score of the OSDI in the GD group was significantly (p < 0.001) higher with respect to the control group. Conclusions: This study shows that the tear film and cornea are damaged in newly non-exophthalmic GD subjects.