The Impact of Soft CL Wear on Corneal Curvature and Thickness and on the Outcomes of Refractive Laser Surgery

Introduction: Soft CL (SCL) wear can alter the cornea and have significant effects on vision quality (Hardten and Gosavi, 2009; Pflugfelder et al., 2002; Ryan and Jacob, 1996; Tseng et al., 2007). This may have implications for visual outcomes following corneal refractive surgery (CRS) (Tang et al., 2005). The time required for resolution of these SCL-induced changes can vary (González-Méijome et al., 2003a; Hashemi et al., 2008; Ng et al., 2007; Nourouzi et al., 2006; Schornack, 2003; Wang et al., 2002b). Despite this, current guidelines relating to cessation of SCL wear prior to CRS vary greatly, and are lacking in relation to the criteria required to achieve stability of measurements (FDA, 2014; Royal College of Ophthalmologists, 2011). Purpose: To examine the influence of SCL wear on cornea structure, the corneal epithelium and endothelium and the outcomes of CRS. Methodology: The cornea and CRS outcomes were compared between patients who wore SCLs (n = 179) against a non-CL wearing control group (NCL) (n= 148). Results and conclusion: SCL wear had a significant effect on corneal curvature (mean anterior inferior tangential radii SCL 7.77mm, NCL 7.90mm, p = 0.04). Peripheral endothelial cell density (SCL = 3109 cells/mm2, NCL = 2935.08 cells/mm2, p = 0.03), mean endothelial cell area (SCL = 322.25 cells/mm2, NCL = 346.92 cells/mm2, p = 0.00) and coefficient of variation of cell size (SCL = 29.13, NCL = 25.63, p = 0.00) were significantly affected by SCL wear. Six weeks following LASIK central epithelial thickness was significantly thicker in the SCL group (59.65 ±6.20μm) compared with the NCL group (54.42 ±8.12μm, p = 0.04) whereas the epithelial thickness in the nasal periphery was significantly thinner in the SCL group (59.52 ±7.01μm) compared with the NCL group (65.83 ±9.16μm, p = 0.03). Although 24 hours was insufficient for resolution of these changes, 2 weeks SCL cessation was sufficient. Previous SCL wear had no negative impact on visual outcomes following CRS compared with a NCL control group, regardless of previous SCL cessation time prior to CRS (all p values \u3e 0.05)

The Prevalence of Demodex Folliculorum on Eyelashes of Symptomatic and Asymptomatic Normal Patients

Purpose To examine the prevalence of Demodex Folliculorum (DF) on the eyelashes of symptomatic and asymptomatic patients. DF is an eight legged ectoparasite present in humans. It is most commonly found on the face; cheeks, nose, chin and eyelashes. Ocular symptoms of DF infestation on the eyelashes include itching, dryness, surface irritation, burning, foreign body sensation, photophobia and reduced vision1 Method Students and patients of the National Optometry Centre (NOC) (n=54), aged 19 – 78 years of age were assessed and sub-divided into 4 groups; Group (1) Control (n=12), Group (2) Signs, no symptoms (n = ?), Group (3) Symptoms, no signs (n = ?) and Group (4) Signs and symptoms (n = ?). Each subject completed a novel DF questionnaire on ocular symptoms and lifestyle. Habitual distance visual acuity was assessed and a slit lamp examination was conducted. 8 lashes – 2 from each eyelid were manipulated and epilated for microscopic examination. Presence of DF was noted and adult DF count was recorded using the modified Coston method2. Results A two-way ANOVA was used to analyse the prevalence of DF (significance level p ≤ 0.05). The DF count significantly increased with age (p = 0.000), contact lens wear (p = 0.037), skin conditions (p = 0.025) and frequency of cleaning pillow case (p = 0.005). There was no significant link (p ≥ 0.05) between the DF count and gender, wearing make-up, allergies, the method of washing and drying pillow cases, method and frequency of lid hygiene routine. A two-way ANOVA was also used to analyse the age and lifestyle of patients who were more symptomatic (significance level p ≤ 0.05). Patient were more symptomatic with age (p = 0.000), contact lens wear (p = 0.032), less frequent lid hygiene routine (p = 0.001), method of lid hygiene (p = 0.000), less frequent pillow case cleaning (p = 0.032), air dried pillow case (p = 0.025), allergies (p = 0.000), skin conditions (p = 0.011), wearing mascara (p = 0.000). Conclusion The prevalence of DF and symptoms increase with age, contact lens wear, skin conditions and frequency of cleaning pillow cases. Whilst patients with less frequent lid hygiene routine, different method of lid hygiene routine, allergies and who air dried their pillow case were more symptomatic, the DF count did not increase. Therefore some patients can be symptomatic without an increase in DF count. Further data collection is ongoing

Ocular Demodex folliculorum: prevalence and associated symptoms in an Irish population

Purpose To investigate the prevalence of ocular Demodex folliculorum (DF) in an Irish population. To validate a modified Ocular Surface Disease Index questionnaire and employ it to evaluate the relationship between dry eye symptoms and the presence of DF. Methods One hundred and fifty-six subjects were enrolled in an epidemiological cross-sectional prevalence study. Each subject completed a novel questionnaire on ocular symptoms and was assessed for the presence of DF. Data was analysed to assess prevalence and to search for significant links between each symptom and DF. Results An overall prevalence of 68% was found. Total mean number of DF found on microscopic examination was 3.83 mites per subject (range 0–25). The presence of symptoms was higher among individuals with DF (P = 0.04). Itch was found to be the symptom most significantly associated with the presence and number of DF (P = 0.025 and P = 0.035, respectively). The questionnaire showed good internal consistency (Cronbach’s alpha; a[0.7) and good reliability (Intra-class Correlation Co-efficient; ICC[0.7). The sensitivity and specificity of a positive symptom result using the questionnaire were 70.8% and 46.9%, respectively. Conclusion There is a strong association between the prevalence of DF and symptoms, in particular itchy eyes. However, not all patients with DF will be symptomatic. The newly developed questionnaire is a reliable instrument for measuring change in symptoms over a period of time and suitable for observing patient reported outcomes in interventional treatment studies

The Efficacy of Warm Compresses in the Treatment of Meibomian Gland Dysfunction and Demodex Folliculorum Blepharitis

Purpose: To investigate and compare the effect of warm compresses on meibomian gland dysfunction and Demodex folliculorum blepharitis. Methods: Forty-two subjects (13 males, 29 females; mean age of 56.45 years) enrolled and completed the two-month warm compress treatment study. Three warm compress therapies were compared: Warm face cloth, MGDRx EyeBag® and OPTASETM Moist Heat Mask. Subjects attended for four visits: baseline, two weeks, four weeks, and eight weeks. Subjective symptoms, osmolarity, non-invasive tear break-up time, ocular surface staining, Schirmer I test, meibum expressibility and clarity, and eyelash manipulation and epilation to assess for the presence of Demodex folliculorum, were measured at each visit. Results: Meibomian gland dysfunction, based on a composite score of meibum quality and expressibility, reduced significantly with the MGDRx EyeBag® and the OPTASETM Moist Heat Mask (p \u3c .05). There was no significant difference in efficacy for treating meibomian gland dysfunction between the two devices (p = .29). No improvement in meibomian gland dysfunction was detected with the warm face cloth. Only the OPTASETM Moist Heat Mask significantly reduced the quantity of Demodex folliculorum over eight-weeks of treatment (p = .036, only baseline to week eight significant p = .008). Symptoms and ocular surface staining improved significantly in all three groups (p \u3c .05). There was no significant change observed in osmolarity, non-invasive tear break-up time or Schirmer I test within each group (p \u3e .05, respectively). Conclusion: TheMGDRx EyeBag® and the OPTASETM Moist Heat Mask exhibited superior efficacy in treating signs and symptoms of meibomian gland dysfunction, compared to the use of a warm face cloth, over the eight-week period. The OPTASETM Moist Heat Mask demonstrated dual therapeutic abilities, treating both meibomian gland dysfunction and Demodex folliculorum blepharitis. Repeated application of heat for the treatment ofmeibomian gland dysfunctionmay continue to present a good home-remedy option for patients

The Effect of Two Weeks and Twenty-Four Hours Soft Contact Lens Cessation Times on Corneal Refractive Surgery Outcomes

Purpose To investigate the influence of previous soft contact lens (SCL) wear on outcomes of corneal refractive surgery (CRS). SCL wear can reduce accuracy of pre-operative corneal measurements and outcomes of CRS. Short SCL cessation times prior to CRS may be insufficient for resolution of SCL-induced corneal changes. It was hypothesised that the visual and refractive CRS outcomes would be worse in a SCL group compared to a non-contact lens (NCL) group and worse in a SCL group who ceased SCL wear for 24 hours when compared to those who ceased SCL wear for two weeks prior to examination and treatment. Method CRS outcomes for dominant eyes of two groups of previous full-time SCL wearing patients were analysed retrospectively; those who ceased SCL wear for two weeks (n = 45) and twenty four hours (n = 49) prior to examination and treatment. In both groups results were compared to a NCL control group (2 weeks NCL group n = 45; 24 hours NCL group n = 49). LASIK and PRK/LASEK one, three and six months post-operative outcomes were assessed for efficacy (unaided distance visual acuity (UDVA) and residual refractive error), predictability (number of eyes within ± 0.25D and ± 0.50D of desired refractive outcome) and safety. Results There was a trend towards superior CRS outcomes for efficacy, predictability and safety in the two weeks SCL cessation group compared to NCL group. These results were significantly better for LogMAR UDVA in the SCL group and were maintained to the six month post-operative visit (LASIK SCL: -0.10 ± 0.10, NCL: -0.06 ± 0.07, p = 0.03; LASEK/PRK SCL: -0.10 ± 0.08, NCL -0.04 ± 0.08, p = 0.03). These findings were reiterated in the 24 hours SCL cessation group where the trend towards superior CRS outcomes for efficacy, predictability and safety in the SCL group compared to the NCL group was continued. UDVA efficacy outcomes following LASEK/PRK were significantly better in the SCL group at the six month post-operative visit (SCL: -0.11 ± 0.03, NCL -0.04 ± 0.07, p = 0.03). Conclusion Previous SCL wear did not negatively impact on CRS outcomes. SCL cessation times of two weeks and twenty four hours did not result in negative outcomes compared to a NCL control group. While these results were statistically significant, the number of letters difference in UDVA between the SCL and NCL groups was low and so one cannot conclude that these results are clinically significant