Osama M. A. Ibrahim

Randomized bilateral comparison of excimer laser in situ keratomileusis and photorefractive keratectomy for 2.50 to 8.00 diopters of myopia

OBJECTIVE To compare effectiveness, safety, and stability of excimer laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) for low-to-moderate myopia. DESIGN Prospective, randomized, bilateral study. PARTICIPANTS Thirty-three patients with a manifest refraction of -2.50 to -8.00 diopters (D) participated. INTERVENTION For each patient, one eye received LASIK and the other received PRK. The first eye treated, and surgical method in the first eye, were randomized. Both eyes were treated by the same surgeon during the same operative session with a Summit Omnimed I laser (6-mm-diameter ablation) and a Chiron Automated Corneal Shaper. Follow-up was 90% at 1 and 2 years. RESULTS At baseline, mean (+/-standard deviation) spherical equivalent manifest refraction was -4.80 +/- 1.60 D in LASIK-treated eyes and -4.70 +/- 1.50 D in PRK-treated eyes. At 1 day after surgery, 81% of patients (21 eyes) reported no pain in the LASIK-treated eye, whereas no patient (0%) reported being pain-free in the PRK-treated eye. At 3 to 4 days after surgery, 18 (80%) LASIK-treated eyes either improved or remained within 1 line of baseline spectacle-corrected visual acuity; only 10 (45%) PRK-treated eyes achieved this result. At 2 years after surgery, 18 (61%) LASIK- and 10 (36%) PRK-treated eyes achieved an uncorrected visual acuity of 20/20 or better, with no statistically significant difference in refractive outcome between the two techniques. Quantitative videokeratography showed more regularity after LASIK. Complications were similar in the two groups. Patients preferred LASIK by a margin of 2 to 1 at 1 year but showed no preference at 2 years. CONCLUSIONS Using a 6-mm-diameter single-pass, large area ablation and an automated microkeratome to treat myopia of -2.50 to -8.00 D with 1.00 D or less astigmatism in 1994, the authors used LASIK to produce a higher percentage of eyes with an uncorrected visual acuity of 20/20 or better, more regular postoperative corneal topography, less postoperative pain, and more rapid recovery of baseline spectacle-corrected visual acuity than PRK. Both LASIK and PRK achieved successful correction of low-to-moderate myopia at 1 and 2 years after surgery.

Application of visante optical coherence tomography tear meniscus height measurement in the diagnosis of dry eye disease

PURPOSE To investigate the applicability of tear meniscus height (TMH) measurement using Visante optical coherence tomography (OCT) in the diagnosis of dry eye disease. DESIGN Prospective, controlled, single-center study. PARTICIPANTS Twenty-four right eyes of 24 patients (6 males, 18 females; mean age, 63.14±13.4 years) with definite dry eye according to the Japanese dry eye diagnostic criteria and 27 right eyes of 27 control subjects (12 males, 15 females; mean age, 56.04±14.22 years) were recruited. METHODS All subjects underwent slit-lamp TMH measurement, OCT upper and lower TMH measurements, tear film breakup time (BUT) measurements, vital stainings, and Schirmer test. The results were compared between the 2 groups by Mann-Whitney test. MAIN OUTCOME MEASURES The correlation between the clinical findings of slit-lamp TMH, strip meniscometry examination, tear functions, vital staining scores, and the OCT upper and lower TMH parameters were tested by Spearmans correlation test. Receiver operating characteristic (ROC) curve technique was used to evaluate the sensitivity, specificity and cutoff values of OCT TMH examination in the diagnosis of dry eye. RESULTS The OCT upper and lower TMH values, slit-lamp TMH, strip meniscometry, tear film BUT, and vital staining scores were significantly lower in the dry eye patients compared with controls (P<0.001). A significant correlation between the OCT upper and lower TMH measurements as well as slit-lamp TMH, strip meniscometry, tear functions, vital staining scores, and the Schirmer test was found. The ROC curve technique analysis of the OCT lower TMH showed that, when the cutoff value was set at <0.30 mm, the sensitivity and specificity of the testing were 67% and 81%, respectively. CONCLUSIONS The Visante OCT is a quick, noninvasive method for assessing the TMH, with acceptable sensitivity, specificity, and repeatability, and may have potential applications for the diagnosis and evaluation of dry eye disease.

The Efficacy, Sensitivity, and Specificity of In Vivo Laser Confocal Microscopy in the Diagnosis of Meibomian Gland Dysfunction

PURPOSE To evaluate the efficacy, sensitivity and specificity of confocal microscopy (CM) parameters: meibomian gland (MG) acinar longest diameter (MGALD), MG acinar shortest diameter (MGASD), inflammatory cell density (ICD), and MG acinar unit density (MGAUD) in the diagnosis of MG dysfunction (MGD). DESIGN Prospective, controlled, single-center study. PARTICIPANTS Twenty MGD patients (9 males, 11 females; mean age, 63.5+/-16.5 years) and 26 age- and gender-matched control subjects (13 males, 13 females; mean age, 53.2+/-15.7 years) were recruited. METHODS All subjects underwent slit-lamp examinations, tear film break-up time (BUT) measurements, assessment of tear evaporation rate from the ocular surface (TEROS), vital stainings, Schirmer test, meibography, MG expressibility, and CM of the MG. Data were compared between the 2 groups using the Mann-Whitney and chi-square tests. MAIN OUTCOME MEASURES The correlation between the clinical findings of tear functions, vital staining scores, and the 4 CM parameters were tested by Spearmans correlation coefficient by rank test. Receiver operating characteristic curve technique was used to evaluate the sensitivity, specificity, and cutoff values of CM parameters. RESULTS The mean tear film BUT, vital staining scores, TEROS values, MG expressibility, and MG dropout grades by meibography were significantly worse in MGD patients compared with controls (P<0.001). The mean values of the MGALD, MGASD, ICD, and MGAUD in MGD patients were significantly worse than those observed in the controls with CM. All CM parameters showed a strong, significant correlation with tear functions, ocular surface vital stainings, MG expressibility, and MG dropout grades. The cutoff values for MGALD, MGASD, ICD, and MGAUD in the diagnosis of MGD were 65 microm, 25 microm, 300 cells/mm2, and 70 glands/mm2, respectively. The sensitivity and specificity values of these parameters under these cutoff values were 90% and 81% for MGALD, 86% and 96% for MGASD, 100% and 100% for ICD, 81% and 81% for MGAUD. CONCLUSIONS Confocal microscopy has the potential to diagnose the simple MGD with high sensitivity and specificity. The CM-based diagnostic parameters correlated significantly and strongly with the status of the ocular surface disease. FINANCIAL DISCLOSURE(S) The authors have no proprietary or commercial interest in any of the materials discussed in this article.

The evaluation of the treatment response in obstructive meibomian gland disease by in vivo laser confocal microscopy

PurposeTo evaluate the status of periglandular inflammation, ocular surface and tear function alterations in patients with obstructive meibomian gland disease (OMGD) by in vivo confocal microscopy before and after anti-inflammatory treatment, and to compare the results with patients receiving only topical non-preserved artificial tears and sodium hyaluronate eye drops without anti-inflammatory agents.MethodsThirty-two eyes of 16 OMGD patients receiving anti-inflammatory treatment (treatment group) and 22 eyes of 11 OMGD patients receiving only topical non-preserved artificial tears and sodium hyaluronate eye drops (control group) were recruited in this prospective study. All subjects underwent slit-lamp examinations, tear film break-up time (BUT) measurements, fluorescein and Rose-Bengal stainings, Schirmer test І without anesthesia, transillumination of the lids (meibography), and in vivo laser confocal microscopy of the lids (HRTII-RCM).ResultsThe mean BUT, fluorescein staining scores, and inflammatory cell densities observed by in vivo confocal microscopy improved significantly in the group receiving anti-inflammatory treatment (p < 0.05), whereas no significant alterations of these parameters were observed in the group not receiving anti-inflammatory agents (p > 0.05).ConclusionsIn vivo confocal microscopy was able to effectively demonstrate the treatment responses in patients with OMGD. Inflammatory cell density calculation seems to be a promising new parameter of in vivo confocal microscopy in the evaluation of treatment responses.

Evaluation of lipid oxidative stress status in Sjögren syndrome patients

PURPOSE We evaluated the levels of lipid oxidative stress markers and inflammatory cells from tears and conjunctiva of patients with Sjögren syndrome (SS) and normal subjects. METHODS We examined 31 eyes of 16 patients (16 females) with SS and 15 eyes of 10 healthy controls (2 males and 8 females) in this prospective study. All subjects underwent a Schirmer test, measurement of tear film break-up time, vital stainings, confocal microscopy of the conjunctiva, tear collection for hexanoyl-lysine (HEL), ELISA, and conjunctival brush cytology. Brush cytology samples underwent immunohistochemistry (IHC) staining with HEL and 4-hydroxy-2-nonenal (4HNE). Hematoxylin-eosin and IHC staining with HEL and 4HNE also were performed on conjunctival samples of SS patients and controls. RESULTS The tear stability and vital staining scores were significantly worse in eyes of SS patients compared to the controls. Conjunctival inflammatory cell density was significantly higher in SS subjects compared to controls. The numbers of conjunctival cells stained positively for HEL and 4HNE were significantly higher in SS patients compared to controls. Tear HEL concentrations correlated significantly with staining scores and inflammatory cell density in confocal microscopy. Conjunctival specimens also revealed higher numbers of cells stained positively for inflammatory markers, as well as HEL and 4HNE in the IHC stainings. CONCLUSIONS Increase of the oxidative stress status in the conjunctiva of SS patients appears to have a role in the pathogenesis of dry eye disease. A close relationship may exist between reactive oxygen species (ROS) production, lipid peroxidation related membrane damage, and inflammatory processes in dry eye.

Tear cytokine and ocular surface alterations following brief passive cigarette smoke exposure

PURPOSE To prospectively investigate the effects of acute passive cigarette smoke exposure on the ocular surface and tear film in healthy non-smokers. METHODS Twelve right eyes of 12 subjects without any ocular diseases were examined before, 5 min, and 24h after 5 min of passive cigarette smoke exposure in a controlled smoke chamber. Tear samples were obtained before, 5 min and 24 h after smoke exposure to detect tear hexanoyl-lysine (HEL), acrolein and inflammatory cytokine concentrations. Tear evaporation rate, DR-1 tear film lipid layer interferometry, tear film break-up time (TBUT), ocular surface fluorescein staining (FS) and Rose Bengal staining (RB), Schirmer I test were performed before, 5 min, and 24h after smoke exposure. Conjunctival impression cytology (IC) and brush cytology (BC) were carried out before and 24h after smoke exposure. RESULTS Tear evaporation rate, tear lipid spread time, tear film break-up time, and vital staining scores showed significant worsening with passive smoke exposure. Tear HEL and IL-6 concentrations increased significantly 24 h after smoke exposure. Tear acrolein level showed an insignificant increase at 5 min. IC and RT-PCR revealed a significant reduction in goblet cell density, a shift toward higher squamous metaplasia grades and a significant downregulation of MUC5AC mRNA expression at 24 h. CONCLUSION Even brief passive exposure to cigarette smoke in healthy non-smoker subjects was associated with adverse effects on the ocular surface health as evidenced by an increase of tear inflammatory cytokines, tear lipid peroxidation products and decrease of mucosal defense resulting in tear instability and damage to the ocular surface epithelia.

Conjunctival in vivo confocal scanning laser microscopy in patients with sjögren syndrome

PURPOSE To demonstrate the conjunctival alterations in patients with Sjögrens (SSDE) and non-Sjögrens syndrome dry eye (NSSDE) using a new generation confocal microscope (HRTII/ RCM; Heidelberg Engineering, Heidelberg, Germany), in a prospective controlled study. METHODS Twenty-eight right eyes of 28 patients with SSDE (28 women; mean age, 58.2 +/- 14.3 years), 7 right eyes of patients with NSSDE (7 women; mean age, 66.1 +/- 14.4 years), and 14 right eyes of 14 age- and sex-matched control subjects were studied. All subjects underwent the Schirmer test, tear film breakup time (BUT), vital staining, and confocal microscopy of the temporal bulbar conjunctiva. The density of conjunctival epithelial cells, epithelial microcysts, and conjunctival and corneal inflammatory infiltrates were also assessed. RESULTS The tear quantity, stability, and vital staining scores were significantly worse in patients with SSDE or NSSDE than in control subjects (P < 0.001 and P < 0.05, respectively). Eyes of the patients with SSDE or NSSDE had a significantly higher density of conjunctival and corneal inflammatory infiltrates than did the control eyes (P < 0.001). Conjunctival inflammatory cell densities showed a negative correlation with tear stability and tear quantity and a positive correlation with the vital staining scores. Conjunctival epithelial cell densities were significantly lower in SSDE and NSSDE compared with control subjects (P < 0.05). The density of epithelial cysts was significantly higher in SS than in healthy control eyes (P < 0.001). CONCLUSIONS Confocal scanning laser microscopy was an efficient and a noninvasive tool for the quantitative assessment of the conjunctival inflammation and epithelial cell densities as well as evaluation of conjunctival morphologic alterations, such as microcysts in patients with SSDE and NSSDE dry eye disease.

The Impact of Contact Lens Wear and Visual Display Terminal Work on Ocular Surface and Tear Functions in Office Workers

PURPOSE To evaluate the effect of contact lens (CL) wear and visual display terminal (VDT) work on the ocular surface and tear functions. DESIGN Prospective case-control study. METHODS Sixty-nine CL wearers (45 women and 24 men; mean age, 35.2 ± 7.3 years), and 102 age- and sex-matched non-CL wearers were enrolled in the study (66 women and 36 men; mean age, 36.7 ± 7.3 years). Ocular surface and tear function tests, including vital stainings (fluorescein and rose bengal), Schirmer test, tear meniscus height measurement, and tear film break-up time were performed. The subjective symptoms of dry eyes were evaluated using a dry eye symptom questionnaire. The participants were divided into 4 subgroups according to the total time of VDT work in 1 day (VDT work time in 1 day ≥ 4 hours or < 4 hours) and presence of CL wear. Main outcome measures included ocular surface vital staining scores, Schirmer test results, tear film break-up time, tear meniscus height measurement, and symptom questionnaire score. RESULTS CL users and long-term VDT workers showed significantly worse tear meniscus height values than non-CL users and short-term VDT workers (P < .001). The mean visual symptom scores in CL wearers and long-term VDT workers were significantly higher than the other groups (P < .001). CONCLUSIONS Office workers who wore CLs and spent more than 4 hours engaged in VDT work had a lower tear meniscus volume with significant dry eye and visual symptoms triggered by environmental factors.

The effects of 2 week senofilcon—A silicone hydrogel contact lens daily wear on tear functions and ocular surface health status

PURPOSE To prospectively investigate the effects of 2 week senofilcon A contact lens (CL) daily wear on the functional visual acuity (VA), ocular surface and tear film. METHODS Seventeen right eyes of 17 senofilcon A CL wearers without any ocular or systemic diseases were examined before and 2 weeks after lens wear. Visual acuity measurements, tear evaporation rate, ELISA for tear cytokines, strip meniscometry, tear lipid layer interferometry, tear film break-up time (BUT), in vivo confocal microscopy, corneal sensitivity, ocular surface vital staining, Schirmer I test and brush cytology for MUC5AC mRNA expression were performed before and after CL wear. RESULTS The best corrected Landolt VA, functional VA parameters, the mean lipid layer interferometry grades, tear evaporation rates, Schirmer test values, vital staining scores and in vivo confocal microscopy parameters did not show any significant differences after 2 weeks of CL wear. The tear film BUT showed a significant decrease together with a significant down regulation of MUC5 AC mRNA expression after CL wear. A statistically significant elevation in the mean tear interleukin (IL)-6 concentration was also observed after 2 weeks of CL wear. CONCLUSIONS Two week senofilcon A daily CL wear seems to be associated with tear instability, a decrease in MUC5AC expression, and elevation of IL-6 in tears without significant alterations in epithelial damage scores or in the morphology or density of in vivo keratoconjunctival cells and nerves. Alterations associated with long term wear and patients with dry eye disease need to be studied in future trials.

The role of oxidative stress and inflammation in conjunctivochalasis

Purpose. To investigate the status of oxidative stress and histopathologic alterations in patients with conjunctivochalasis and compare the findings with those in healthy control subjects. Methods. Eleven patients (n = 20 eyes) with Yokoi grade 3 conjunctivochalasis and 11 health control subjects (n = 22 eyes) were prospectively recruited. ELISA for tear hexanoyl-lysine (HEL) and inflammatory cytokines, tear film break-up time tests, Schirmer test measurements, and fluorescein and rose bengal vital staining were performed. Conjunctival specimens obtained during surgery for conjunctivochalasis and cataract underwent immunohistochemical staining for HEL+8-OHdG, MMP-3, and MMP-9, and positively stained cells were counted. Transmission electron microscopy was also performed, with staining for elastic fibers in the conjunctival stroma. Results. The mean tear stability and vital staining scores were significantly worse in the conjunctivochalasis patients than in the control subjects. The tear HEL and tear cytokine levels showed significantly higher values in eyes with conjunctivochalasis. IL-1beta and IL-6 levels showed a significant correlation with corneal epithelial damage. IL-1beta and TNFalpha showed a significant correlation with 8-OHdG-stained cell counts. Specimens from patients with conjunctivochalasis revealed a significantly higher number of cells positively stained for HEL, 8-OHdG, MMP-3, and MMP-9 than did specimens from age- and sex-matched control subjects. Transmission electron microscopy showed decreased intercellular cohesiveness, with the conjunctival stroma showing an accumulation of elastic fibers. Conclusions. Lipid and DNA oxidative stress were present in the conjunctiva. Increased tear inflammation seemed to coexist with loss of conjunctival epithelial cohesiveness and increased collagenolytic activity, which may explain the conjunctival laxity observed in patients with conjunctivochalasis.