Eye & Contact Lens - Current Issue

An Update of Eye Shape and Myopia Abstract: Myopia is one of the most prevalent eye diseases, and its advanced form, high myopia, is a leading cause of subsequent pathologic myopia, which in turn results in an increased risk of retinal diseases. The prevalence of myopia and high myopia is 28.3% and 4.0% of the global population, respectively, and these numbers are estimated to increase to 49.8% for myopia 9.8% for high myopia by 2050, thus making myopia a severe global socioeconomic problem. The eye shape has been receiving increasing attention as a possible biomarker for myopia. Among several modalities, magnetic resonance imaging (MRI) is currently considered to be the best to measure the 3-dimensional eye shape, and one study using MRI revealed that myopic eyes became much larger in all 3 dimensions, but more so in length (0.35 mm/D) than in height (0.19 mm/D) or in width (0.10 mm/D), which fitted in global and axial elongation models. Another recent study reported that emmetropic retinas were oblate but oblateness decreased with myopia progression. According to a study to evaluate eye shapes in high myopia, although all emmetropic eyes had a blunt shape, almost half of the high myopic eyes had a pointed shape. Multiple lines of evidence suggest that abnormal eye shape changes can cause not only simple myopia but also various ocular complications through biomechanical stretching. In this review, we highlight recent findings on eye shape changes in myopic eyes and abnormal eye shapes in pathologic myopia.

Herpes Zoster Ophthalmicus Review and Prevention Abstract: Varicella-zoster virus (VZV) is the etiologic agent of both chickenpox and Herpes zoster (HZ). In the United States, there are around one million cases of HZ per year. Ten percent of HZ cases are subtyped as herpes zoster ophthalmicus (HZO) specifically and involve the V1 distribution. Herpes zoster ophthalmicus is a significant cause of blindness in the United States. This article will provide a basic overview of VZV, HZ, and HZO with a focus on preventative measures in an effort to prevent blindness through improving clinician awareness and education. The differences in clinical effectiveness and duration of effectiveness of the live (Zostavax) and recombinant vaccines (Shingrix) are illustrated. There is now a trend toward using the recombinant vaccine as recommended by the Advisory Committee for Immunization Practices (ACIP) for healthy adults 50 or older.

The Role of Soft Contact Lens Wear on Meibomian Gland Morphology and Function Purpose: To evaluate the impact of soft contact lens (CL) wear on the morphology and function of the meibomian glands (MG). Methods: One hundred seventy-three eyes of 87 soft CL wearers and 103 eyes of 55 age-matched healthy volunteers were included into this study. The patients were divided into 3 groups according to the total duration of lens wear: less than 3 years, 3 to 7 years, and more than 7 years. Ocular Surface Disease Index (OSDI) scores, slitlamp biomicroscopy findings, fluorescein staining of the ocular surface, tear film break-up time (BUT), Schirmer I test, and meibography findings were recorded in all patient eyes and were compared with controls. Results: The mean meiboscores of the upper and lower eyelids were significantly higher in CL wearers compared with controls (P<0.05). The mean BUT and the mean MG expressibility were significantly lower, whereas the mean OSDI score, corneal staining scores, percentage of partial/complete gland loss, and percentage of thickened and curled MG in upper/lower lids were statistically significantly higher in CL wearers (P<0.05). Meiboscores were significantly higher in patients with a total lens wear duration of more than 3 years compared to those with less than 3 years of lens wear for both upper/lower lids (P<0.05). The earliest morphological change in the MG of CL wearers was MG thickening, and this parameter was the only meibography finding that had the highest diagnostic ability for MG dysfunction. Conclusion: Soft CL wear causes significant morphological and functional changes in MG with thickening of MG presenting an early diagnostic finding of MG dysfunction on meibography.

Contact Lens Versus Non–Contact Lens–Related Corneal Ulcers at an Academic Center Purpose: To compare the infectious contact lens–related corneal ulcer (CLRU) and non-CLRU cases at Saint Louis University. Methods: Retrospective review of corneal ulcer cases identified by search of the ophthalmology and microbiology department databases between 1999 and 2016. Results: Six hundred seventy-seven cases of corneal ulcers were identified, of which 46% were CLRU. CLRU cases were seen more commonly in younger patients (P<0.001) and women (P=0.03) than non-CLRU cases. Many of the infections were vision-threatening as defined by central/paracentral location (73% CLRU and 71% non-CLRU [P=0.60]) and large size of ulcer >2 mm2 in 36% CLRU and 51% non-CLRU (P=0.002). Causative pathogen in cultured CLRU was predominately Pseudomonas species (44%, P<0.001 vs. the non-CLRU group), other gram-negative (6%), gram-positive (33%), fungi (13%), and Acanthamoeba (5%). Comparatively, cultured non-CLRU was predominately gram-positive (64%, P<0.001 vs. the CLRU group), gram-negative (26%), and fungi (11%). The combined oxacillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus isolates were 35% and 34%, respectively. Despite the progressive increase in the number of corneal ulcers seen, the annual trend for any one particular organism for either CLRU cases or non-CLRU cases did not change significantly. Conclusions: Most of the cases were non-CLRU. CLRU was disproportionately associated with Pseudomonas species and non-CLRU with Staphylococcal species. Fungal infections were predominately caused by filamentous organisms in both groups. Acanthamoeba keratitis was exclusively associated with CL use.

Postoperative Endophthalmitis Before and After Preferred Utilization of Prophylactic Intracameral Antibiotics for Phacoemulsification Cataract Surgeries at Cole Eye Institute Purpose: To compare the rate of endophthalmitis of intracameral versus topical antibiotic prophylaxis for patients undergoing phacoemulsification at a single-centered, multispecialty ophthalmological institute. Methods: A retrospective analysis of the rate of endophthalmitis by coding search within 90 days of cataract surgery in periods before (May 15, 2012–May 15, 2014) and after (April 30, 2015–April 30, 2017) intracameral antibiotics became the institution's preferred practice pattern for phacoemulsification. Clinical data were collected for each endophthalmitis case, including timing of onset, presenting symptoms and signs, culture results, treatment performed, and visual acuity outcome. Results: The rate of postphacoemulsification endophthalmitis decreased from 0.18% (29 eyes among 16,201 cataract surgeries) to 0.07% (11 eyes among 16,325 surgeries) when the preferred method was changed from topical to intracameral antibiotics (P=0.004) with an odds ratio of 0.32. Endophthalmitis cases in the 2 groups had comparable visual acuity at initial presentation and at 3 months (P=0.86). The most commonly isolated organism in culture-proven cases of endophthalmitis in both groups was coagulase-negative staphylococcus. The rate of gram-positive endophthalmitis decreased from 0.08% to 0.02% with an odds ratio of 0.23 (P=0.012) while the rate of gram-negative cases remained similar. Conclusions: The use of intracameral antibiotics during cataract surgery was associated with a statistically significant reduction of postoperative endophthalmitis.

Dry Eye Symptoms May Have Association With Psychological Stress in Medical Students Purpose: To evaluate the prevalence and risk factors of symptomatic dry eye disease (DED) among medical students. Methods: This cross-sectional study included 209 students at a medical school in Korea. Dry eye symptoms were assessed using a 9-item questionnaire, and DED was defined as having one or more dry eye symptoms often or all the time. The ocular surface disease index (OSDI) and visual analog scale (VAS) questionnaires were also administered to quantify the dry eye symptoms. A survey including demographic data, potential risk factors for DED, personal habits, and psychological stress was also performed. Results: Of the 209 students, 188 (93 men and 95 women) completed the survey. The average age was 28.0±2.5 (mean±SD; range, 23–37) years. Prevalence of DED was 27.1% (51/188). Participants with DED had significantly higher VAS and OSDI than those without DED (P<0.001 for both). Univariate analysis revealed that female sex (P=0.001), contact lens (CL) wear (P=0.034), prolonged computer use (P=0.001), and higher psychological stress score (P<0.001) had significant association with DED. Multivariate analysis also showed the significant association between DED and female sex (P=0.026), CL wear (P=0.042), prolonged computer use (P=0.004), and higher stress score (P=0.014). Conclusions: Symptomatic DED was prevalent among medical students. Increased psychological stress was associated with higher risk of DED. Its risk also increased among women, CL wearers, and prolonged computer users.

Treatment Limitations With PROSE (Prosthetic Replacement of the Ocular Surface Ecosystem): One Centers Experience Objectives: The prosthetic replacement of the ocular surface ecosystem (PROSE) device is used to treat difficult-to-manage ocular surface disease (OSD) and ectasia. Previous studies have demonstrated positive treatment outcomes. This study aims to document treatment failures to better tailor treatment and address limitations with its use. Methods: Retrospective chart review of consecutive PROSE fits performed at Northwell Health from 2012 to 2016. Reasons for patient discontinuation of treatment were documented, and potential risk factors for treatment failure were assessed. Results: The total number of eyes treated was 125. Fifty five eyes had ectasia, 67 had OSD, and 3 had both ectasia and OSD. A total of 8/125 (6.4%) of eyes failed treatment; 6/8 (75%) of failed treatments had worsening corneal edema, all of which had presumed risk factors for lower endothelial cell counts. Two eyes discontinued use secondary to intractable debris on the device, blurring vision. The most common diseases in patients failing therapy in descending order included: keratoconus and Fuch's dystrophy, ectasia after penetrating keratoplasty, and graft versus host disease. Those with presumed risks factors for lower endothelial cell counts (Fuch's dystrophy and patients with previous penetrating keratoplasty) were more likely to fail (22.2%) compared with those without a risk of a low endothelial cell count (1.6%). Conclusion: Although PROSE use has high success, corneal edema secondary to endothelial dysfunction is a potential limitation that may lead to treatment failure. Patients with lower endothelial cell counts after penetrating keratoplasty or with Fuch's dystrophy were more likely to fail treatment.

Impact of Corneoscleral Contact Lens Usage on Corneal Biomechanical Parameters in Keratoconic Eyes Objective: To analyze the changes in corneal biomechanical parameters of keratoconic eyes with and without intracorneal ring segment (ICRS) implants after 1 year of corneoscleral contact lens (CScL) wear. Methods: Seventy-four eyes of 74 patients were divided into three groups: healthy subjects (29 eyes, control group), and 2 groups of subjects with keratoconic eyes (one group of 20 eyes with ICRS implants and one of 25 eyes without them), which were fitted with CScL. Corneal hysteresis (CH), corneal resistance factor (CRF), and corneal-compensated intraocular pressure (IOPcc) were evaluated before fitting CScL and after 1 year of CScL wear. In addition, endothelial cell count (ECC) and central corneal thickness (CCT) were also recorded. Results: Corneal biomechanical parameters were lower in keratoconic corneas than in healthy corneas. Keratoconic eyes with ICRS implants had lower values than eyes without them for CH (mean±SD, 8.09±1.29 vs. 8.63±1.5 mm Hg, respectively, P=0.120), CRF (6.99±1.38 vs. 8.37±1.52 mm Hg, respectively, P=0.03), and also for CCT and ECC. Data for IOPcc were similar in all groups. After 1-year wearing CScL, no statistically significant differences in corneal biomechanical parameters were registered in any of the groups (all P>0.05), although slight differences (0.13–0.27 mm Hg) were found. Conclusion: The viscoelasticity properties of the cornea did not change significantly when wearing corneoscleral contact lenses for 1 year, and therefore, these lenses seem to be safe and healthy and are a reasonable alternative option for keratoconus management.

Longitudinal Evaluation of the Progression of Keratoconus Using a Novel Progression Display Objectives: To evaluate the longitudinal tomographic changes and to compare the discriminatory potential of a novel progression display between progressive and nonprogressive keratoconic eyes. Methods: Retrospective evaluation was made of 81 eyes of 81 patients with keratoconus who had undergone Scheimpflug measurements at least twice with an interval of 12 months or longer between each measurement. The progressive group was defined as 36 eyes, which showed progression according to the definition of the global consensus on keratoconus and ectatic diseases when 2 of the 3 criteria were met, and the other 45 eyes were considered the nonprogressive group. The main outcome measures from progression display were “A” for anterior radius of curvature, “B” for posterior radius of curvature, “C” for thinnest pachymetry, “D” for distance visual acuity; Kmax; Q-value front and back; index of surface variance (ISV), vertical asymmetry, height asymmetry, and height decentration; overall deviation of normality (final D); average pachymetric progression index; and maximum Ambrósio relational thickness. Results: The rate of change per year of A, B, C, thinnest pachymetry, Kmax, final D, and ISV was significantly different between groups (P≤0.01 for all values). It was determined that yearly change rates greater than 0.12 for A, 0.14 for B, 10.04 μm for thinnest pachymetry, 0.68 D for Kmax, 0.15 for final D, and 2.11 for ISV might indicate progression in keratoconus management. Conclusions: Belin progression display parameters may be useful in discriminating progressive from nonprogressive keratoconic eyes.

Diversity of Ocular Surface Bacterial Microbiome Adherent to Worn Contact Lenses and Bacterial Communities Associated With Care Solution Use Purpose: This study assessed microbiome adherent to contact lenses and defined the bacterial communities associated with use of lens care solutions. Methods: Among 84 lenses screened for adherent ocular surface bacterial microbiome using 16S rRNA molecular amplification, 63 (75%) generated bacterial-specific amplicons processed using the Ion Torrent Personal Genome Machine workflow. Data were stratified by solution use (peroxide vs. polyhexamethylene biguanide [PHMB]–preserved multipurpose solution [MPS]). Diversity of lens-adherent microbiome was characterized using Shannon diversity index and richness index. Data were analyzed using principal components analysis and Kruskal–Wallis tests. Results: We identified 19 phyla and 167 genera of bacteria adherent to the lenses. Proteobacteria was the most abundant phyla, followed by Firmicutes and Actinobacteria. The most abundant bacterial genera (>1% abundance) were Ralstonia, Enterococcus, Streptococcus, Halomonas, Corynebacterium, Staphylococcus, Acinetobacter, Shewanella, Rhodococcus, and Cobetia. Sixteen of 20 lenses (80%) negative for bacterial DNA were worn by participants using peroxide solutions while only 4 (20%) were MPS-treated lenses (P=0.004). Genera diversity of lens-adherent microbiome showed a significant increase in MPS-treated lenses compared with peroxide (P=0.038). Abundance of Corynebacterium, Haemophilus, and Streptococcus were increased 4.3-, 12.3-, and 2.7-fold, respectively, in the MPS group compared with peroxide (P=0.014, 0.006, 0.047, respectively). Conclusions: Commensal, environmental, and pathogenic bacteria known to be present in the conjunctival microbiome can be detected on worn contact lenses. Although most contact lenses worn by asymptomatic wearers harbor bacterial DNA, compared with peroxide, lenses stored in a PHMB–preserved MPS have more quantifiable, abundant, and diverse bacterial communities adherent to them.