History Of Contact Lens Use Research Articles

Corneal Layer Thickness Mapping With Optical Coherence Tomography in Different Stages Reveals Pathologic Processes of Keratoconus.

The aim of this study was to characterize the corneal layer thickness profile in different stages of keratoconus (KC). Patients with clinical or subclinical KC without a history of contact lens use were retrospectively enrolled. We evaluated 164 eyes, including 69 clinical KC, 32 topographic KC (no clinical signs), 22 very asymmetric ectasia with normal topography and no clinical signs of ectasia (VAE-NT), and 41 control eyes. The corneal epithelial, stromal, and total thicknesses in a 10-mm diameter were evaluated using swept-source anterior segment optical coherence tomography. The epithelial thickness in the control and VAE-NT groups was thicker inferiorly than superiorly. While epithelial thickness parameters between the VAE-NT and control groups did not differ, significant stromal thinning was observed in the paracentral inferior and midperipheral temporal areas. The epithelium in the topographic and clinical KC groups was thinner than that in the control and VAE-NT groups, with focal thinning of the epithelium in the inferior-temporal area. In clinical KC, stromal thinning increased mainly in the central and paracentral inferior/temporal areas. With KC progression, the thinnest epithelial points tended to be placed temporally and inferiorly. Corneal layer thickness mapping using swept-source optical coherence tomography in a 10-mm diameter cornea across various severities of KC, from very mild to advanced, revealed that epithelial and stromal thicknesses changed with KC severity and was involved in the pathogenesis of KC progression. Pathological changes in the stroma may precede those in the epithelium. Epithelial compensatory mechanisms in clinical and topographic KC may not have fully emerged in VAE-NT.

Relationship Between Contact Lens Wear and the Risk of Acquired Blepharoptosis

Abstract
 Introduction & Objectives : Contact lens wear has been reported to be associated with acquired blepharoptosis. This literature review aims to summarize and evaluate the risk of acquired blepharoptosis in contact lens wearers.
 Methods : Literature searching was conducted using three online databases including PubMed, Cochrane Library, and Embase. Search terms such as “contact lens”, “ptosis”, and “blepharoptosis” were included. Reference lists of each study were also assessed for potentially relevant sources. Prospective and retrospective studies as well as meta-analyses and systematic reviews were included.
 Results : Using relevant search terms in various databases, a total of five articles were included in this review. Four studies suggested that wearing hard or soft contact lenses was significantly associated with blepharoptosis. One study indicated hard contact lens wearers presented blepharoptosis 17.38 times more frequently than non-wearers (OR, 17.38, 95% CI=3.71–81.29), while soft contact lens wearers had 8.12 times more risk of presenting blepharoptosis than non-wearers (OR, 8.12, 95% CI=2.68–24.87). Furthermore, long-term contact lens wear, which was 20 years or more, seemed to have a significant effect on the incidence of blepharoptosis. There was only one study which stated that hard contact lens wear did not lead to acquired blepharoptosis in this review.
 Conclusion : There is evidence of a clear association between hard or soft contact lens wear and an increased risk of blepharoptosis. Patients wearing contact lenses should be informed of the risk of blepharoptosis, and a history of contact lens use should be sought in all patients who have acquired blepharoptosis.

Pearls and Paradigms in the Management of Acanthamoeba Keratitis: A Review

Abstract Acanthamoeba keratitis (AK) generally displays a protracted course with significant morbidity. This is partly due to the fact that it is often misdiagnosed as viral or fungal keratitis. It is associated most with contact lens (CL) wear in developed countries, and exposure to soil or unsanitary water in the developing countries. The textbook description of AK includes the presence of ring infiltration, radial keratoneuritis, and disproportionate pain. Of the patients that presented to our tertiary care center, only 40% had a history of CL use, and 33% had a ring infiltrate. Corneal scraping for microbiological culture on non-nutrient agar serves as the gold standard for diagnosis. Corneal biopsy and confocal microscopy hold diagnostic value in deeper lesions, and polymerase chain reaction and newer molecular techniques are emerging as rapid and effective tools. Biguanides are the drug of choice for AK. But it is important to reconstitute these drugs in correct dosages; otherwise, corneal toxicity can take place. The use of corticosteroids in AK is a matter of debate. We have used corticosteroids in cases with persistent keratitis, severe pain, and extra-corneal manifestations under the cover of amoebicidal therapy. Surgical intervention in the acute phase is reserved for advanced AK with limbus encroachment, perforations, or fulminant corneal abscesses. AK is thus a severe, potentially blinding disease, where a prompt diagnosis ensuring the timely commencement of amoebicidal therapy is an essential component of improving the patient’s prognosis. In this article, we have discussed the presentation, challenges in diagnosis and management, and our experience in managing AK.

Profile of Pseudomonas aeruginosa Antibiotic Sensitivity Test Results from Corneal Scrapings Specimens of Keratitis Patients with Contact Lens Users and Non-Contact Lenses Users at Dr. Soetomo Hospital Surabaya

Background: Pseudomonas aeruginosa have a significant proportion of the causes of bacterial keratitis. Corneal ulcers infected with P. aeruginosa are more severe than other bacterial corneal ulcers. P. aeruginosa is often associated with keratitis that results from wearing contact lenses, which eventually leads to corneal ulcers. This study aims to determine the differences in the results of the antibiotic sensitivity test of P. aeruginosa from corneal scraping specimens of keratitis patients using contact lenses and non-contact lens users at RSUD dr. Soetomo. Methods: This study is an observational analytic study of secondary data from corneal scraping cultures of patients with keratitis infected with P. aeruginosa at Dr. Soetomo Hospital period January 2017-December 2020. Results: The total number of samples included in the inclusion criteria was 46 samples. Of the total sample, 8 (17.40%) were contact lens users and 38 (82.60%) were non-contact lenses. The male sex and female sex each as much as 50%. The distribution of sample age categories for 0-20 years was 21.74%, 21-40 years was 13.04%, 41-60 years was 41.30%, and >60 years was 23.91%. Based on samples from 8 contact lens patients, antibiotics were found to be 100% sensitive, namely Amikacin, Cefepime, Ciprofloxacin, Imipenem, Levofloxacin, Meropenem, and Piperacillin tazobactam, Aztreonam and Gentamicin 87.5%, Ceftazidime 75%, Tobramycin 37.5% and Piperacillin 25%. Meanwhile, from a sample of 38 patients who did not wear contact lenses, the sensitive antibiotics were Cefepime 100%, Meropenem 94.8%, Amikacin 92.1% Imipenem 86.9%, Piperacillin-tazobactam 76.3%, Ciprofloxacin 73.8%, Gentamicin 73.8%, Aztreonam 68.4%, Levofloxacin 68.4%, Piperacillin 50%, Ceftazidime 44.7%, and Tobramycin 28.9%. Conclusion: The results of the antibiotic sensitivity test against P. aeruginosa from keratitis patients with a history of contact lens use showed that 8/8 (100%) of the active antibiotics were Amikacin, Cefepime, Ciprofloxacin, Imipenem, Levofloxacin, Meropenem, and Piperacillin tazobactam. Then followed by Aztreonam and Gentamicin (7/8). The results of the antibiotic sensitivity test against P. aeruginosa from keratitis patients who had no history of using contact lenses showed that the active antibiotics were above 50%, namely Cefepime 38/38 (100%), Meropenem 36/38 (94.8%), Amikacin 35 /38 (92.1%), Imipenem 33/38 (86.9%), Piperacillin-tazobactam 29/38 (76.3%), Ciprofloxacin 28/38 (73.8%), Gentamicin 28/38 (73 .8%), Aztreonam 26/38 (68.4%), and Levofloxacin 26/38 (68.4%). Keywords: Antibiotic sensitivity, Pseudomonas aeruginosa, keratitis, contact lenses

Role of Different Types of Contact Lenses in Epithelial Thickness.

To evaluate the potential role of different types of contact lenses, such as soft (SCL), hard (HCL), and mini scleral (SCCL), in corneal epithelial thickness with anterior segment optical coherence tomography (AS-OCT). In this cross-sectional study, patients who used contact lens at recent 6 months were recruited consecutively from September 2019 to October 2019, and the epithelial thicknesses of the cornea were obtained by AS-OCT and compared with control subjects who did not use contact lens. In total, 184 eyes (115 subjects) were included; of them, 75 eyes were keratoconic (KCN) and 109 eyes were nonkeratoconic (non-KCN). Twenty eyes in KCN and 79 eyes of non-KCN group had no history of contact lens use and were included for comparison with KCN and non-KCN contact lens users, respectively. Mean duration of contact lens wearing was 75.63±50.42 months. The epithelial thickness of non-KCN SCL group was thinner than that of non-KCN control subjects all over the cornea, whereas the epithelium of non-KCN HCL was thinner at central site as well as nasal and temporal paracentral and midperipheral areas. Epithelial thickness of the KCN HCL group was not different from the KCN control subjects in all sectors. The KCN SCCL group had thinner epithelium at nearly all peripheral sectors as well as inferior, inferotemporal, inferonasal, and nasal midperipheral sectors compared with KCN control subjects. The corneal epithelium was thinner at the peripheral zones in KCN SCCL users; at both peripheral and central zones in non-KCN SCL users and in central zones in non-KCN HCL users.

Prevalence and risk factors of dry eye disease among University Students in Bangkok, Thailand.

PurposeTo investigate the prevalence of dry eye disease (DED) and its associated risk factors among Thai university students.MethodsA cross-sectional study using an electronic survey was conducted in two Rajabhat universities in Bangkok, Thailand. The woman’s health study questionnaire was used to determine students with DED. The prevalence of DED along with 95% confidence interval (CI) were calculated. Logistic regression model was used to identify the associated risk factors.ResultsA total of 4,111 university students joined and completed the survey questionnaires. Mean age was 18.8 ± 1.1 years with female predominance (2874 students, 69.91%). Clinically diagnosed DED was reported in 136 students (3.31%), while severe symptoms of eye dryness and irritation were reported in 227 students (5.52%). The prevalence of DED among Thai university students was 8.15% (95% CI 7.33% to 9.02%). History of contact lens use and high screen time (> 8 hours per day) were reported in 868 students (21.11%) and 2101 students (51.11%), respectively. Male gender, contact lens use and high screen time were significantly associated with higher risk of DED with the adjusted ORs (95% CI) of 1.39 (1.09, 1.77), 2.49 (1.96, 3.17), and 1.43 (1.14, 1.80), respectively.ConclusionsDED is not rare among Thai university students. Contact lens use and high screen time are two significant modifiable risk factors of DED in our students. These findings can raise awareness of DED in youth population and provide valuable information for public health promotion in university students.

Results From the German Fungal Keratitis Registry: Significant Differences Between Cases With and Without a History of Contact Lens Use.

Fungal keratitis (FK) is a serious ophthalmic disease with a potentially devastating outcome that seems to be increasing in recent years. The use of contact lenses (CLs) was evaluated as a risk factor for FK to determine possible differences in course and outcome. Data from 173 cases reported in the German FK registry until August 2019 were evaluated regarding CL behavior, other ophthalmological and general risk factors, age, sex, identified pathogens, conservative and surgical therapy, visual acuity, and findings at admission and follow-up. One hundred seventy-four eyes from 173 patients between 2000 and 2019 were included [64.4% women, median age 54 (39; 72) years]; 49.7% wore CL, of which 81.3% were soft CL, and 50.3% had no history of contact lens use (NCL). CL users were significantly more often women and otherwise healthy (CL: 80.2% vs. NCL: 48.9%; P < 0.0001). The spectrum of pathogens among CL users showed a significantly higher proportion of infections with filamentous pathogens, in particular Fusarium sp. (total filament: CL 69.8% vs. NCL 27.3%; P = 0.0001; Fusarium sp.: CL 50.0% vs. NCL 14.8%; P < 0.0001). Overall, 54.6% required keratoplasty and 8.6% enucleation. CLS are the most important risk factor for FK in Germany. With CLs, typically, the infection is caused by molds, and patients are comparably younger and otherwise healthy. Often, extensive surgery is needed. To evaluate changes in the pathogen and resistance spectrum and to further monitor possible CL-related risk factors, a consistent collection of data remains paramount.

Polymicrobial Keratitis: Risk Factors, Clinical Characteristics, Bacterial Profile, and Antimicrobial Resistance.

To describe clinical characteristics, complications, and the most prevalent microorganisms causing polymicrobial keratitis and their antibiotic sensitivities. A cross-sectional study including a consecutive analysis of patient's records with a diagnosis of bacterial keratitis with a positive culture and antibiogram report were included. Patients were grouped into those having monomicrobial and polymicrobial infection. Features studied included demographic and clinical characteristics, risk factors, Gram stain, cultures, and antibiotic sensitivity. We included 656 patients; in 31.5% more than one microorganism was found. Seven hundred and twenty-three gram-positive bacteria were isolated, and 336 (46.5%) had polymicrobial keratitis. One hundred sixty-one gram-negative bacteria were isolated, and 99 (61.5%) from polymicrobial keratitis. Fourteen (0.60%) patients presented ring infiltrate, and 10 (71.42%) of those patients had polymicrobial keratitis (X2 10.654, P=0.001). Multivariate analysis showed that patients with history of contact lens use (odds ratio [OR] of 1.78, P=0.042), coexistent autoimmune disease (OR 4.64, P=0.03), irregular edges of the infiltrate (OR 2.06, P=0.005), and ring infiltrate (OR 6.034, P=0.005) have a higher risk for developing polymicrobial infection. In the polymicrobial group, gram-positive and gram-negative organisms showed a high sensitivity to Netilmicin. We found a high incidence of polymicrobial keratitis. Our results suggest that it should be suspected in patients with a history of contact lens use, coexistent autoimmune disease, infiltrates with indistinct edges, and ring infiltrates. Sensitivities to moxifloxacin are lower than those reported in previous studies, but sensitivity to Netilmicin is higher.

Distribution of central corneal thickness and intraocular pressure in emmetropic eyes of healthy children of Palestine: a representative cross-sectional study.

To determine the distributions of central corneal thickness (CCT) and intraocular pressure (IOP) in emmetropic eyes of healthy children of Palestine. This representative cross sectional study included a total of 1156 eyes from 578 healthy school children aged 7-15y. Inclusion criteria included emmetropia, no previous history of ocular or systemic diseases, no previous history of contact lens use, and the availability of both eyes. CCT and IOP were measured using ultrasound pachymeter and Goldmann applanation tonometer, respectively. The relationship of the results with age and gender was investigated. The mean age of school children was 11.13±2.8y. Mean CCT was 542.2±37.4 and 544.3±39.2 µm for right and left eyes, respectively. Mean IOP was 12.5±2.2 and 12.3±2.2 mm Hg for right and left eyes, respectively. A positive correlation was observed between CCT and IOP of the right eye (P<0.001, R=0.358) and CCT and IOP of the left eye (P<0.001, R=0.324). No significant differences were observed in CCT and IOP due to age or gender (P>0.05). There were significant differences in mean CCT and IOP between right and left eyes (P=0.004, P=0.001, respectively). A population profile of CCT and IOP is established in Palestinian children for the first time. Mean CCT is comparable to some studies but differ from others. Mean IOP is considerably lower than that of majority children of other ethnic groups. Intereye difference of more than 36 µm in CCT, and 5 mm Hg in IOP should prompt evaluation for potential ocular disorders.

Corneal Biomechanical Changes Following Toric Soft Contact Lens Wear.

Purpose:To determine the effect of using toric soft contact lenses on corneal biomechanical properties.Methods:We enrolled 33 healthy patients with mean age of 23.18 ± 4.06 and minimal cylinder power of 1 D (-1.98 ± 0.808 SD) and negative history of contact lens use; keratoconic patients were excluded from the study. Toric soft contact lenses (BIOFINITY, Comfilcon A, Coopervision, Southampton, UK) were fitted in all participants. The Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, New York, USA) was used to measure corneal hysteresis (CH), corneal resistance factor (CRF), and the Pentacam HR (Oculus, Inc., Lynnwood, WA, USA) was used to measure central corneal thickness (CCT) and mean keratometry (K mean) before and one week, one month, and three months after using the toric soft contact lenses.Results:CH and CRF were decreased significantly one month after using the contact lens; mean CH decreased from 9.99 ± 1.44 to 9.59 ± 1.54 mmHg, and mean CRF decreased from 9.96 ± 1.71 to 9.63 ± 1.73 mmHg (P = 0.013 and P = 0.017, respectively). Mean CCT and K mean did not show a significant change during the period of toric soft contact lens use.Conclusion:CH and CRF decreased significantly one month after fitting toric soft contact lenses while CCT and Kmean did not change significantly. Corneal biomechanical parameters may alter with toric soft contact lens use and such changes may have implications with long-term use such lenses.

The Risk of Blepharoptosis in Contact Lens Wearers

The aim of this systematic review was to summarize and evaluate the risk of blepharoptosis in contact lens wearers. In a PubMed search, 393 papers were found using the terms "lens and ptosis." The abstracts were read and 16 full text articles were reviewed. Among them, 5 articles were analyzed. Five studies were subgrouped and a meta-analysis of these data suggested there is an increased risk of blepharoptosis in hard contact lens wearers over nonwearers (n = 7426, OR, 17.38, 95% CI = 3.71-81.29, P < 0.00001). One study was subgrouped and these data suggested there is also an increased risk of blepharoptosis in soft contact lens wearers over nonwearers (n = 90, OR, 8.12, 95% CI = 2.68-24.87, P < 0.0002). Patients wearing rigid contact lenses should be advised of the risk of ptosis, and a history of contact lens use should be sought in all patients who have acquired ptosis as the previous authors have recommended.

In vivo corneal confocal microscopic analysis in patients with keratoconus.

To quantify corneal ultrastructure using laser scanning in vivo confocal microscopy (IVCM) in patients with keratoconus and control subjects. Unscarred corneas of 78 keratoconic subjects without a history of contact lens use and 36 age-matched control subjects were evaluated with slit-lamp examination (SLE), corneal topography and laser scanning IVCM. One eye was randomly chosen for analysis. Anterior and posterior stromal keratocyte, endothelial cell and basal epithelial cell densities and sub-basal nerve structure were evaluated. IVCM qualitatively demonstrated enlarged basal epithelial cells, structural changes in sub-basal and stromal nerve fibers, abnormal stromal keratocytes and keratocyte nuclei, and pleomorphism and enlargement of endothelial cells. Compared with control subjects, significant reductions in basal epithelial cell density (5817±306 cells/mm(2) vs 4802±508 cells/mm(2), P<0.001), anterior stromal keratocyte density (800±111 cells/mm(2) vs 555±115 cells/mm(2), P<0.001), posterior stromal keratocyte density (333±34 cells/mm(2) vs 270±47 cells/mm(2), P<0.001), endothelial cell density (2875±223 cells/mm(2) vs 2686±265 cells/mm(2), P<0.001), sub-basal nerve fiber density (31.2±8.4 nerves/mm(2) vs 18.1±9.2 nerves/mm(2), P<0.001), sub-basal nerve fiber length (21.4±3.4 mm/mm(2) vs 16.1±5.1 mm/mm(2), P<0.001), and sub-basal nerve branch density (median 50.0 (first quartile 31.2 - third quartile 68.7) nerve branches/mm(2) vs median 25.0 (first quartile 6.2 - third quartile 45.3) nerve branches/mm(2), P<0.001) were observed in patients with keratoconus. Significant microstructural abnormalities were identified in all corneal layers in the eyes of subjects with keratoconus using IVCM. This non-invasive in vivo technique provides an important means to define and follow progress of microstructural changes in patients with keratoconus.

Assessment of corneal endothelial cell density in patients with keratoconus not using contact lenses

To assess the corneal endothelial cell density (ECD) in keratoconus patients with no history of contact lens use. Yuzuncu Yil University, School of Medicine and Van Training and Research Hospital, Department of Ophthalmology, Van, Turkey. Cross-sectional controlled study. The eyes of 65 patients with the diagnosis of keratoconus with no history of contact lens wear and the eyes of 40 healthy controls were prospectively examined using the Heidelberg Retinal Tomography Rostock Cornea Module (HRT3/RCM). The average ECD from the two groups were then compared. Of the cases with keratoconus, 44 (67.7%) were men and 21 (32.3%) were women. The mean age was 20.9±6.8 (range=10-41) years. Of the controls, 28 (70%) were men and 12 (30%) were women. The mean age was 23.9±5.8 (range=14-35) years. Of the 65 eyes with keratoconus, 19 (29.2%) had mild keratoconus, 21 (32.3%) had moderate keratoconus, and 25 (38.5%) had severe keratoconus. The mean ECD was 2731.6±303.2 cells/mm2 in cases with keratoconus and 2664.9±319.5 cells/mm2 in controls. There was no difference between the densities (unpaired t-test, P=0.4). No significant relationships were found between the ECD data and central corneal thickness or steepest keratometric. Endothelial cell density was unaltered in keratoconic patients without a history of contact lens use when compared with healthy controls. Change in ECD is independent from the central corneal thickness and the stage of keratoconus.

Pythium insidiosum Keratitis in Israel

To report with morphologic and phylogenetic speciation the first case from Israel of Pythium insidiosum keratitis associated with contact-lens wear. Case report and literature review. A 21-year-old man with a history of contact-lens use and water exposure was hospitalized in Israel for a corneal ulcer. The ulcer progressed despite intensive antibiotics. He flew home to the United States for further care. Examination revealed a corneal ulcer with hypopyon. The infection progressed despite intensive medical therapy, and a therapeutic penetrating keratoplasty was performed. Histology and cornea cultures from the host cornea revealed sparsely septate, branching hyphae, consistent with P. insidiosum. DNA sequencing of the Pythium isolate supported the clinical history that the infection was acquired outside of the United States. Despite intensive medical therapy and a second corneal transplant, the ulcer progressed, ultimately requiring enucleation. This is the first reported case of culture-proven, contact lens-related Pythium keratitis originating from Israel. Pythium is a fungus-like, aquatic oomycete found in tropical climates. Human pythiosis is uncommon but associated with high morbidity. Case reports describe surgical cure of Pythium keratitis, but this case recurred despite two penetrating keratoplasties and maximal antifungal therapy. In cases of presumed fungal keratitis that do not respond to antifungals, the fungus should be sent for speciation because early surgical intervention is the only means to save the eye in ocular pythiosis.

Fungal keratitis associated with ocular rosacea

In order to report fungal keratitis in patients of ocular rosacea, a retrospective review of all cases of fungal keratitis was undertaken. Cases in which ocular rosacea coexisted were identified and included in the study. The clinical course of patients thus identified was studied from the medical records and outcomes were evaluated. A total of three cases of fungal keratitis with coexisting ocular rosacea were identified. All three patients were known cases of acne rosacea with an intermittent, irregular treatment for the same. Previous history of contact lens use, ocular surgery or trauma was not present in any of the cases. Microbiological evaluation revealed Aspergillus flavus as the causative organism in two patients and an unidentified hyaline fungus in the third. Patients received simultaneous therapy for fungal keratitis and ocular rosacea. The ocular surface completely stabilized and the infiltrate resolved in all three cases. The chronic ocular surface changes and induced inflammation in ocular rosacea, along with the instillation of topical steroids for therapy, may create an environmental milieu favorable for fungal keratitis. Microbiological evaluation should be considered, even in cases of suspected sterile keratitis, prior to treatment with topical steroids, so as to prevent the possible worsening of an associated infective corneal condition.

Infectious Keratitis in Keratoconus With Corneal Hydrops Without Contact Lens Wear: A Case Report

Infectious keratitis after contact lens use is a known complication in cases of corneal hydrops. A case of infectious keratitis is reported in a case of keratoconus with corneal hydrops without any known predisposing factors. Infectious keratitis was diagnosed in a 58-year-old man with spontaneous onset of pain, redness, photophobia, and decreased vision. There was no history of contact lens use or any ocular allergy. Noncoagulase staphylococci were cultured from the corneal scrapings, and treatment was started with fortified antibiotics. Response to treatment was noted, and the patient is awaiting keratoplasty. This case report highlights the occurrence of infectious keratitis in a case of keratoconus with corneal hydrops without any antecedent history of contact lens use.

In vivo Confocal Microscopy for the Evaluation of Corneal Microstructure in Keratoconus

Purpose: To evaluate the corneal microstructure in keratoconus with in vivo confocal microscopy (IVCM). Methods: Unscarred corneas of 68 patients with keratoconus and 22 controls were evaluated with slit lamp examination, corneal topography, and IVCM (Confoscan 3.0, Vigonza, Italy). One eye was randomly chosen for analysis. Keratocyte, endothelial cell and basal epithelial densities, sub-basal and stromal nerve structure, and severity of stromal haze were evaluated. Results: Compared with corneas of control subjects, patients with keratoconus had a significantly lower anterior stromal keratocyte density (1279 ± 197 cells/mm2 vs. 1132 ± 178 cells/mm2, p = 0.002), lower midstromal keratocyte density (904 ± 213 cells/mm2 vs. 770 ± 120 cells/mm2, p < 0.001), lower posterior stromal keratocyte density (935 ± 113 cells/mm2 vs. 725 ± 113 cells/mm2, p < 0.001), lower endothelial cell density (2924 ± 300 cells/mm2 vs. 2719 ± 279 cells/mm2, p = 0.004), lower basal epithelial cell density (5987 ± 699 cells/mm2 vs. 4365 ± 537 cells/mm2, p < 0.001), lower sub-basal long nerve density (32.0 ± 6.5 nerves/mm2 vs. 19.6 ± 6.5 nerves/mm2, p < 0.001), thicker sub-basal (3.2 ± 0.4 μm vs. 3.7 ± 1.1 μm, p = 0.01) and stromal nerves (5.0 ± 1.2 μm vs. 8.0 ± 2.9 μm, p < 0.001), and higher proportion of corneas with haze (40.9% vs. 92.6%, p < 0.001). A history of contact lens use (n = 12) was not associated with lower keratocyte, endothelial cell, or basal epithelial cell counts. Conclusions: Corneal microstructure is abnormal in patients with keratoconus. Keratocyte and endothelial cell loss appears to be present in keratoconic corneas.

Smoking Associated With Damage to the Lipid Layer of the Ocular Surface

To evaluate the effects of smoking on ocular surface. Prospective, comparative, interventional case series. setting: Institutional. study population: Sixty smokers (33 men, 27 women) and 34 healthy subjects (18 men, 16 women) were enrolled into this study. Patients with associated ophthalmic or systemic diseases, and history of contact lens use and ocular surgery were excluded. The duration of average smoking was 13.1 years (range 5 to 35 years). Ocular surface was evaluated by measuring corneal and conjunctival sensitivity, surface staining with fluorescein, tear film breakup time, Schirmer 1 test, and conjunctival impression cytology. Dry eye symptoms were scored by questionnaire. Kinetic analysis of sequential tear interference images obtained by a DR-1 tear lipid layer interferometry was used to investigate the precorneal lipid layer spread. Results were compared with a control group. Comparison of subjective complaints with objective parameters in cigarette smokers and normal subjects. In the smoker group, the mean Schirmer 1 test value was 10.8 mm (range 8 to 14 mm). The mean breakup time was 5.3 seconds (range 1 to 10 seconds), the average conjunctival sensitivity was 26.2 mm (range 0 to 45 mm), and the average central corneal sensitivity was 37.6 mm (range 5 to 60 mm). There was no statistically significant difference in goblet cell densities or in Schirmer 1 test values between smokers and controls (P > .05). Higher grades of lipid layer changes were observed in smokers by DR-1 interferometry kinetic analysis. Smoking has deteriorating effects on the lipid layer of precorneal tear film.