Central Corneal Haze Research Articles

Clinical Outcomes of Infectious Keratitis Associated with Contact Lens Wear Following Penetrating Keratoplasty: A Case Series.

To report on the clinical characteristics, and outcomes of patients who developed infectious keratitis associated with contact lens (CL) wear following penetrating keratoplasty (PK). A retrospective chart review was performed to identify all patients who underwent PK between November 2012 and January 2023 at a single tertiary referral practice, and subsequently developed CL related infectious keratitis. 74 patients using CL following PK were identified. Charts were reviewed to obtain data about demographics, ocular history, CL usage, microbial culture reports, visual acuity, treatment, and clinical outcomes. CL-associated infectious keratitis occurred in 9 patients, more frequently in males (66%), and patients had a mean age of 54.5 ± 11.8years old. The identified causative organisms included: Stenotrophomonas maltophilia (N = 3), Candida parapsilosis (N = 2), Moraxella nonliquefaciens (N = 1), Pseudomonas aeruginosa (N = 1), Staphylococcus epidermidis (N = 1), Streptococcus mitis (N = 1), Candida albicans (N = 1), and Acanthamoeba (N = 1). Contact lenses were used following PK for an average of 9.1 ± 10.8months before development of keratitis. Patients were followed for 31.8 ± 30.2months after infection. The mean best corrected visual acuity without CL prior to infection was 20/150 and decreased to 20/260 post-infection. Complications following the contact-lens-associated infectious keratitis included: central corneal haze (N = 8), chronic corneal epithelial defects (N = 3), perforation (N = 3), endophthalmitis (N = 1), and enucleation (N = 1). Three grafts required repeat PK. CL-associated infectious keratitis following PK have high rates of complication. Patients should be monitored closely for signs of infection.

Outcomes of pediatric sterile keratitis posthypotonic collagen cross-linking

Abstract: In this case series, we will describe sterile keratitis in the early postoperative period after hypotonic collagen cross-linking (CXL) in two pediatric cases. This is a retrospective case series of two eyes of two children who developed inflammatory keratitis with central corneal haze after uneventful epithelial-off hypotonic CXL. After ensuring microbiological sterility, appropriate treatment with topical steroids and lubricants was started. There was complete resolution of corneal infiltrates with minimal scarring. Both patients regained almost the preoperative best-corrected visual acuity of 20/80 and 20/60, respectively.

Acute central corneal haze and thinning with atypical keratitis presentation

A 24-year-old woman presented with a 7-day history of blurry vision, redness, and extreme pain in her right eye. She had no pertinent medical or ocular history and did not use spectacles or contacts. Uncorrected distance visual acuity (UDVA) was 20/40 in the right eye and could not be improved with refraction. Slitlamp examination revealed a 1.5 × 1.5 mm central epithelial defect with surrounding white blood cell recruitment. Confocal microscopy (Figure 1JOURNAL/jcrs/04.03/02158034-202304000-00020/figure1/v/2023-03-24T200747Z/r/image-tiff) was performed, and she was treated with chlorhexidine 0.02% drops every hour in the right eye. 2 weeks later, the cornea had completely re-epithelialized; however, persistent corneal haze, decreased visual acuity, and corneal thinning and flattening was noted. Pachymetry was 484 µm in the right eye and UDVA was 20/40 (Supplemental Figure 1, available at http://links.lww.com/JRS/A836). In the following 2 weeks, UDVA improved to 20/25. 6 months after the initial presentation, UDVA was unchanged and faint central corneal haze was noted on examination (Figure 2JOURNAL/jcrs/04.03/02158034-202304000-00020/figure2/v/2023-03-24T200747Z/r/image-tiff). Of interest, her family history is significant for her younger 16-year-old brother with 3 prior episodes of a similar type of keratitis/keratopathy over the course of 2 years in both eyes with similar central paracentral corneal haze, thinning, and flattening and similar confocal findings (Figure 3JOURNAL/jcrs/04.03/02158034-202304000-00020/figure3/v/2023-03-24T200747Z/r/image-tiff). He also was unresponsive to topical antibiotics and antivirals except topical chlorhexidine. Her brother has been our patient for the last several years prior to her first visit to our clinic. What is your diagnosis? What medical diagnostic tests, if any, would you recommend? Is this an infectious or simply an inflammatory response? Is there any genetic or familial predisposition?

Dexamethasone-Eluting Contact Lens for the Prevention of Postphotorefractive Keratectomy Scar in a New Zealand White Rabbit Model.

To evaluate the safety and efficacy of an experimental dexamethasone-eluting contact lens (DCL) for the prevention of postphotorefractive keratectomy (PRK) corneal haze in a New Zealand White (NZW) rabbit model. Both eyes of 29 NZW rabbits underwent PRK. The rabbits were randomized to one of the 5 study arms for 4 weeks: tarsorrhaphy only, tarsorrhaphy and bandage contact lens (BCL) replaced weekly, tarsorrhaphy and BCL for 1 week plus topical 0.1% dexamethasone ophthalmic solution (drops) for 4 weeks, tarsorrhaphy and BCL replaced weekly plus topical dexamethasone for 4 weeks, and tarsorrhaphy and DCL changed weekly for 4 weeks. Each week for 4 consecutive weeks postoperatively, the tarsorrhaphies were opened, the eyes underwent evaluation and imaging, and the tarsorrhaphies were replaced. Contact lenses were cultured on removal. Central corneal haze was assessed weekly with corneal densitometry. After 4 weeks, the animals were killed, and the eyes were enucleated for histopathologic analysis. The tarsorrhaphy only group displayed more haze with a greater change in optical densitometry from pre-op compared with the other treatment groups. There was no difference between the DCL group and the groups receiving a BCL and dexamethasone drops in densitometry or histopathology. No NZW rabbits developed clinical signs of infection, and cultures from DCLs and BCLs grew similar organisms. In the post-PRK rabbit model, DCLs worn weekly for 4 weeks were safe and as effective at preventing corneal haze as 0.1% dexamethasone drops applied 4 times a day for 4 weeks.

Could adverse effects and complications of selective laser trabeculoplasty be decreased by low-power laser therapy?

Selective laser trabeculoplasty (SLT) has been used for treatment of primary open-angle glaucoma, ocular hypertension, pigmenter and pseudoexfoliative glaucoma being considered a low-risk procedure. Therefore, transitory and permanent adverse effects have been reported, including corneal changes, subclinical edema, and reduction in endothelial cells and in central corneal thickness. Despite rarer, serious corneal complications after SLT can be permanent and lead to visual impairment, central corneal haze, opacity and narrowing. The mechanism involves increase of vasoactive and chemotactic cytokines causing inflammatory infiltrate, destruction of stromal collagen by fibroblasts and increase of matrix metalloproteinases type 2, which impair reepithelization. SLT also increases free radical production and reduces antioxidant enzymes, resulting in endothelium damages. Low-power laser therapy (LPLT) has been used in regenerative medicine based on its biostimulatory and anti-inflammatory effects. Biostimulation occurs through the interaction of laser photons with cytochrome C oxidase enzyme, which activates intracellular biochemical cascades causing synthesis of a number of molecules related to anti-inflammatory, regenerative effects, pain relief and reduction in edema. It has been showed that LPLT reduces gene expression related to pro-inflammatory cytokines and matrix metalloproteinases, and it increases expression of growth factors related to its proliferative and healing actions. Although radiations emitted by low-power lasers are considered safe and able to induce therapeutic effects, researches based on experimental models for glaucoma could bring important data if LPLT could be an alternative approach to improve acceptation for patients undergoing SLT.

Keratopathy due to ophthalmic drug abuse with corneal melting and perforation presenting as Mooren-like ulcer: A case report

The present report describes the clinical course and treatment of a Mooren-like ulcer associated with abuse of topical anesthetics and dexamethasone. A 38-year-old male physician treated himself with lidocaine, tetracaine and dexamethasone (DEX) eye drops for severe pain and decline of vision in both eyes. After six months of treatment, his right cornea exhibited annular melting with full-thickness stromal infiltration at the limbus and central corneal haze. His left cornea was completely melted and exhibited iris prolapse. The patient was treated with topical antibiotics, lubricants and underwent a binocular keratoplasty. The surgery was successful and after eight months the postoperative best-corrected visual acuities were counting fingers in the right eye and light perception in the left eye. In summary, this report documents a severe case of keratopathy presenting as Mooren-like ulcer caused by topical anesthetics and DEX, which were treated via keratoplasty, resulting in useful vision being retained.

Central Corneal Thickness After Cross-linking Using High-Definition Optical Coherence Tomography, Ultrasound, and Dual Scheimpflug Tomography: A Comparative Study Over One Year

To assess central corneal thickness (CCT) and corneal haze in keratoconus eyes following corneal cross-linking (CXL). Prospective noncomparative case series. Forty patients (44 eyes) with keratoconus that had serial evaluation for CCT, following CXL, usinghigh-definition optical coherence tomography (HD-OCT), ultrasound pachymetry (USP), and dual Scheimpflug tomography. CCT was measured at baseline, then at 2weeks and 1, 3, 6, and 12months postoperatively. The mean baseline CCT measurements were 470.02μm, 469.79μm, and 466.66μm using the HD-OCT, the USP, and dual Scheimpflug tomography, respectively (P= .91). Following CXL, the mean CCT measurements by dual Scheimpflug, at all follow-up periods, were lower compared to mean baseline reading (P < .003). The mean CCT measurements by the HD-OCT and USP were similar to baseline readings except for the thicker readings at the 2-week follow-up visit. Overall, the mean CCT obtained by the USP was similar to that obtained by the HD-OCT throughout the 12-month period. However, the mean CCT measurements obtained by dual Scheimpflug tomography were statistically and clinically significantly lower than those obtained by both HD-OCT and USP at all follow-up visits. USP and HD-OCT showed better agreement in CCT readings at all visits, and may better estimate the true CCT following CXL as compared to dual Scheimpflug tomography. The lower mean CCTpost-CXL as measured by the latter seems to be correlated with the amount of haze that develops aftercross-linking.

Central corneal haze after wedge resection following penetrating keratoplasty and photorefractive keratectomy

Central corneal haze after wedge resection following penetrating keratoplasty and photorefractive keratectomy

Bevacizumab and Rapamycin Can Decrease Corneal Opacity and Apoptotic Keratocyte Number following Photorefractive Keratectomy

We investigated the effects of bevacizumab and rapamycin on central corneal opacity and apoptotic keratocyte number after photorefractive keratectomy (PRK) followed by ultraviolet B (UV-B) irradiation. A total of 60 right eyes of Sprague-Dawley rats in four groups (n = 15 each) underwent PRK ablation to 80 μm with a 3-mm zone. Sponges soaked with 0.02% mitomycin C (MMC), 2.5% bevacizumab, 0.01% rapamycin, and balanced saline solution were applied for 2 minutes to these eyes in the MMC, bevacizumab, rapamycin, and control groups, respectively. At 3 weeks after PRK, all right eyes were exposed to 100 mJ/cm(2) UV-B irradiation. Biomicroscopy was used to determine the amount of haze, and TUNEL staining for apoptosis and histology were performed at 3, 6, and 12 weeks. Contrary to the results at 3 weeks, central corneal haze, and apoptotic keratocyte and keratocyte number decreased significantly in the MMC, bevacizumab, and rapamycin groups compared to the control group, and the keratocyte number was lower in the MMC group than the bevacizumab and rapamycin groups at 6 weeks (all P < 0.05). At 12 weeks, the apoptotic keratocyte number was lower in the MMC, bevacizumab, and rapamycin groups than the control group, and the keratocyte number was significantly lower in the MMC than the rapamycin and control groups (all P < 0.05). Intraoperative bevacizumab and rapamycin administration decreases central corneal haze and apoptotic keratocyte number after PRK. Bevacizumab and rapamycin may be safe alternatives to MMC during refractive surgery to prevent postoperative corneal opacity less affecting the keratocyte number.

Comparison of Corneal Thickness and Haze in DSAEK and Penetrating Keratoplasty

To compare corneal thickness and haze in Descemet stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PK). This study included 30 consecutive patients undergoing DSAEK (18 patients) and PK (12 patients). Central corneal thickness and corneal haze were analyzed longitudinally by Pentacam (Oculus, Wetzlar, Germany) at 2 weeks, 1 month, and 3 months after grafting. The mean age of patients in the DSAEK group was 71.42 ± 9.91 years (range, 55-85 years) and in the PK group was 60.58 ± 16.58 years (range, 31-81 years). Two weeks, 1 month, and 3 months after surgery, the cornea was significantly thicker in the DSAEK group compared with the PK group (P < 0.01). Two weeks, 1 month, and 3 months after the operation, the cornea had significantly more haze in the DSAEK group compared with the PK group (P < 0.05). Haze in the DSAEK group was mainly observed in the subepithelial stroma. DSAEK grafts were significantly thicker with increased haze for up to 3 months after surgery. Scheimpflug system is available for quantifying not only corneal thickness but also corneal haze after various keratoplasty procedures.

Central Toxic Keratopathy After LASEK

Purpose: We report a case of transient corneal opacity and hyperopia after LASEK surgery. Case summary: A 21-year-old female visited our clinic complaining of decreased visual acuity in the left eye. The patient had undergone LASEK surgeryten days previously. Before LASEK surgery, the central corneal thickness of the left eye was 540 m, and the refractive error was -2.00 Dsph=-0.75 Dcyl 80A with an estimated ablation depth of 52.2 m. At the time of visit (on the tenth day after surgery), the best corrected visual acuity (BCVA) was 0.07, the central corneal thickness was 404 m, and the refractive error was +1.00D=+1.25D 90. Slit-lamp biomicroscopy showed round central corneal haziness, but there were no signs of inflammation. At the third weeks after surgery, the central corneal thickness was 401 m and the refractive error was +11.25D=-4.00D 145. Slit-lamp biomicroscopy showed sustained round central corneal haze. Twenty-two weeks after surgery, the central corneal thickness was 445 m and the refractive error was -0.75D=-1.25D 180. The corneal opacity had disappeared. Conclusions: In case of transient corneal opacity, stromal loss and hyperopic change after LASEK surgery, central toxic keratopathy should be considered.

Epithelial Debridement and Bowman's Layer Polishing for Visually Significant Epithelial Irregularity and Recurrent Corneal Erosions

To report the utility of epithelial debridement and diamond burr polishing of Bowman's layer (ED + DBP) in the management of recurrent corneal erosions and visually significant epithelial irregularity associated with epithelial basement membrane dystrophy (EBMD). Retrospective interventional consecutive case series. All patients who underwent ED + DBP by a single surgeon between November 1, 2002 and November 1, 2008. Data were collected regarding the frequency and severity of symptoms associated with EBMD as well as previous treatments. Details regarding the procedure and the postoperative course were recorded as well. The significance of the improvement in visual acuity after treatment was determined using Wilcoxon signed rank test. Change in visual acuity and recurrent corneal erosions after treatment. ED + DBP was performed on 56 eyes (42 patients) during the 72-month period under review. Of the 56 eyes, 37 (66%) were treated for recurrent corneal erosions and 22 (39%) were treated for visually significant epithelial irregularity (3 eyes were treated for both conditions). EBMD was diagnosed in 46 eyes (82%), and a history of corneal trauma was elicited in 9 eyes (16%). Visual acuity improved significantly (P = 0.016), and recurrent corneal erosions resolved after treatment in 24 (96%) of the 25 eyes with a history of corneal erosions before treatment with more than 3 months of follow-up (average, 18.9 months; range, 3.5-66.5 months). Visual acuity improved significantly (P = 0.004), and visual aberrations related to epithelial irregularity resolved in all 14 eyes treated for visually significant EBMD with more than 3 months of follow-up (average, 14.2 months; range, 3.4-50.8 months). Mild, central subepithelial corneal haze developed in 12 (26%) of the 47 eyes that did not demonstrate subepithelial haze before ED + DBP, although it was not associated with decreased vision at the last follow-up visit in any patient. ED + DBP is a safe and effective technique in the management of recurrent corneal erosions and visually significant epithelial irregularity associated with EBMD.

Late traumatic LASIK flap loss during contact sport

Three years and 5 months after uneventful laser in situ keratomileusis, the left eye of a 39-year-old man was struck by the finger of a friend while the two were practicing karate, resulting in loss of the flap. The patient had performed this contact sport regularly for years. When last seen 16 weeks after injury, the best corrected visual acuity in the left eye was 20/40 with -1.75 -0.50x30. Mild central corneal haze was observed under slitlamp examination, the flap was missing, and the patient complained of dysphotopsia. Pachymetry in the left eye was 394 mum, with an irregular corneal contour. Flap loss is a serious complication because severe irregular astigmatism and unpredictable refractive change can occur. This case highlights the vulnerability of flaps to trauma even late postoperatively.

A Comparison of Gatifloxacin to Ciprofloxacin in the Prophylaxis of Streptococcus pneumoniae in Rabbits in a LASIK Model

To investigate the efficacy of the fourth-generation fluoroquinolone, gatifloxacin 0.3%, compared to ciprofloxacin 0.3%, in preventing Streptococcus pneumoniae keratitis in a rabbit laser in situ keratomileusis (LASIK) model. Twelve albino rabbits had bilateral lamellar flaps created. Group A (eight eyes) was given gatifloxacin 0.3%; group B (eight eyes) was given ciprofloxacin 0.3%; and group C (eight eyes) served as the controls. Groups A and B received one drop of antibiotic 20 minutes before the creation of the lamellar flap, at the conclusion of flap formation, and four times per day for 3 days. All corneas were inoculated with 0.1 mL of 4 x 10 organisms/mL of S. pneumoniae immediately after flap formation. On day 3, all corneas were examined and cultured. Group A (gatifloxacin) had no infiltrates and three areas of 1-mm central corneal haze. On day 3, one of eight corneas had a positive culture. Group B (ciprofloxacin) had seven infiltrates, including one perforation, and six of eight corneas had positive cultures. Group C (control) had eight corneal infiltrates, and all eight corneas had positive cultures. The data show a statistically significant difference between gatifloxacin and ciprofloxacin and gatifloxacin and control for mean infiltrate size and mean culture scores. The fourth-generation fluoroquinolone, topical gatifloxacin 0.3%, is superior to topical ciprofloxacin 0.3% for prophylaxis against a clinical isolate of S. pneumoniae in a rabbit LASIK model.

LASIK Induces Minimal Regrowth and No Haze Development in Rabbit Corneas

Purpose: To quantify central corneal regrowth and haze development after LASIK in rabbits. Methods: New Zealand White rabbits received an 89 μ m (–8 diopters) myopic LASIK and were evaluated during 4 months using slit-lamp and in vivo confocal microscopy to monitor changes in central corneal morphology, epithelial and stromal thickness, flap and bed thickness, and corneal light backscattering (haze). At various timepoints, corneas were processed for histology. Results: Using in vivo confocal microscopy, LASIK induced no detectable morphological changes besides a slightly elevated light backscattering at the interface. Correspondingly, all corneas remained clear with no haze development by slit-lamp biomicroscopy. Corneal thickness was stable by 8 weeks after an increase of 17 ± 4 μ m that consisted of a 13 ± 3 μ m stromal regrowth and a 4 ± 2 μ m epithelial hyperplasia. At the LASIK interface, less than 4 μ m new extracellular matrix was deposited. Accordingly, all LASIK flaps were easily pulled off by 6 months. Conclusions: LASIK induces a minimal wound healing response in rabbit corneas with no haze development and a regrowth (regression) of only 17 μ m of an 89-μ m photoablation. Three main factors contributed to the observed regrowth: epithelial hyperplasia (∼ 4 μ m), matrix deposition at the LASIK interface (∼ 4 μ m), and stromal growth outside the interface within the flap and wound bed (∼ 9 μ m).

Scanning Laser Polarimetry in Corneal Haze after Excimer Laser Refractive Surgery

We evaluate the technique of retinal nerve fiber layer thickness measurement using scanning laser polarimetry in cases of central corneal haze due to photorefractive keratectomy. Nerve fiber layer thickness was measured using a Nerve Fiber Analyzer II (Laser Diagnostic Technologies, Inc., San Diego, CA, U.S.A.) in eight eyes of eight individuals with mild to pronounced corneal haze owing to earlier excimer laser refractive surgery, and in nine eyes of nine control volunteers. Neither total and sectorial nerve fiber layer thickness values, nor superior/ inferior quadrant thickness ratio differed in a statistically significant manner between the two groups (unpaired t test, p > 0.05). Reproducibility in the "haze" and control groups was 4.3% and 3.4%, respectively, for mean nerve fiber layer thickness calculated from all quadrants around the disc. The figures were 4.9% and 5.2%, respectively, for the superior quadrant thickness; 8.2% and 8.8%, respectively, for the temporal thickness values; 5.4% and 4.6%, respectively, for the inferior thickness values; and 4.1% and 5.0%, respectively, for the nasal quadrant thickness values. For the superior/inferior quadrant thickness ratio the reproducibility was 4.4% and 6.8%, respectively. None of the corresponding values for reproducibility differed significantly between the two groups (F-test, p > 0.05). Corneal haze did not cause an artificial increase of the thickness values measured with scanning laser polarimetry and did not diminish the reproducibility of the measurement. The results suggest that scanning laser polarimetry may be a suitable method for the precise measurement of the nerve fiber layer thickness even in eyes with persistent corneal haze after excimer laser refractive surgery.

Direct Objective Quantification of Corneal Haze after Excimer Laser Photorefractive Keratectomy for High Myopia

The purpose of the study is to measure regional distribution differences in corneal haze after excimer laser photorefractive keratectomy for high myopia. The authors developed computerized gradient edge detectors with which were analyzed digitized anterior slit-lamp photographs of 40 eyes, an average of 21.0 plus or minus 14.5 weeks after photorefractive keratectomy for high myopia (-6 to -22 diopters). A treated area an adjacent untreated area on the anterior corneal surface, each containing six regions, were quantified, and the difference was correlated with various parameters. Mean differences between scarred and clear areas for haze grade 0.5, 1.0, 2.0, 3.0, and 4.0 were 16.9, 26.6, 42.6, 60.4, and 76.4 gray levels, respectively (rs = 0.96; P = 0.0001). A low but statistically significant correlation between the intended correction and postoperative corneal haze was found (r = 0.33; P = 0.037). The mean coefficient of variation of the amount of opacification within each treated area was 9.4%. This coefficient of variation increased with a longer follow-up time (r = 0.88; P = 0.0001). The difference in the intensity of haze between the center and more peripheral regions over the entrance pupil did not correlate with the attempted correction. However, a strong association between a relatively less severe central corneal haze with respect to more peripheral haze and longer follow-up time was found (r = -0.96; P = 0.0001). The amount of corneal haze showed a weak positive association with the attempted correction in excimer laser photorefractive keratectomy for high myopia. Corneal haze appeared fairly uniformly distributed within the ablation zone, but a more heterogeneous distribution was found with a longer follow-up time. Furthermore, later postoperative examinations disclosed a clear trend toward diminishing central opacification relative to peripheral regions over the entrance pupil.

A Multicenter Trial of Photorefracti*ve Keratectomy for Residual Myopia after Previous Ocular Surgery

The Summit Therapeutic Refractive Clinical Trial is a nine-center prospective, nonrandomized, self-controlled trial to assess the efficacy, stability, and safety of using a standardized technique of excimer laser photorefractive keratectomy (PRK) to correct residual myopia in eyes with previous refractive surgery or cataract surgery. Eligible eyes with a mean residual myopia of -3.7 +/- 1.8 diopters (D) (range, -0.63 to -11.00 D) underwent PRK with a 193-nm excimer laser for myopic corrections between -1.50 and -7.50 D. Standardized settings were used for the ablation zone, ablation rate, repetition rate, and fluence. One hundred seven of the first 114 treated eyes were examined 1 year after PRK, with 98% of eyes having had refractive keratotomy and 2% having had cataract surgery. One year postoperatively, the mean manifest spherical equivalent refraction was -0.6 +/- 1.4 D (range, -6.50 to 2.50 D); 63% of eyes were within +/-1.00 D of the attempted correction; and uncorrected visual acuity was 20/40 or better in 74% of eyes. Twenty-nine percent of eyes lost two or more Snellen lines of best-corrected visual acuity, and central corneal haze was moderate or severe in 8% of eyes. Excimer laser PRK is effective in reducing residual myopia after previous refractive and cataract surgery. However, it is less accurate than PRK in eyes that did not undergo surgery and is more likely to cause a loss of best-corrected visual acuity 1 year after treatment.