The relationship between symptomatic assessment and clinical signs of dryness in dry eye subjects

Introduction: There was no previous study to assess relationship between dry eye symptoms and signs in the local population. The purpose of this study is to evaluate the relationship of symptomatic assessment and clinical signs of dryness in dry eye subjects. Materials and method: A Cross-sectional study with convenient sampling involving 321 subjects with 642 eyes was done. Subjects were divided into non-dry eye (NDE) and dry eye (DE) groups. The division of NDE and DE groups were done using two types of classification. In Classification 1(symptoms-based), DE was defined if the score of Ocular Surface Disease Index (OSDI) score was more than 33. The value of tear film break-up time (TFBUT) less than 5 seconds and Schirmer test with anaesthesia (STA) less than 5mm/5 minutes were considered as DE for Classification 2 (signs based). Results: There were poor correlations between OSDI and clinical signs of dryness in all subjects involved (p > 0.05). Similar findings were also noted within NDE subjects in Classification 1 and Classification 2. OSDI score was also not significantly correlated with the signs of dryness within DE subjects except with ocular protection index (OPI) (r = -0.14, p = 0.047) in Classification 1 and with conjunctival lissamine green staining (CLGS)(r = 0.23, p = 0.040) in Classification 2. Conclusion: There were no significant correlation between the symptoms of dry eye and the clinical signs of dry eye. Therefore, the clinical diagnosis of dry eye can be made based on either just on the symptoms or the signs

Measurement of Pterygium Tissue Dry Weight Using Two Different Tissue Preparation Techniques in Freeze-Dry Method

Due to pterygium tissue compression on the corneal surface, it has been hypothesised that the degree of corneal astigmatism caused by pterygium can vary. This study aims to develop a freeze-dried method for estimating net pterygium tissue mass (NPTM) as dry weight. A single surgeon (KMK) excised 60 primary pterygium using the controlled partial avulsion technique and divided them into two groups: formalin-fixed (n=30) and unfixed (n=30). After determining the weight of each sterile container, 5 mL of 5% buffered formaldehyde was added to the formalin-fixed group and stored for one week, while 5 mL of distilled water was added to the non-fixed pterygium group. Each container was pre-frozen for 12 hours before being freeze-dried (-24 hours at -80 degrees Celsius). The result is referred to as the net pterygium tissue mass (NPTM). Using an independent T-test, a comparison of wet and dry weight and percentage of NPTM was conducted between groups. Wet weights for formalin-fixed and non-fixed pterygium were 253.33 82.17 g and 255.17 63.52 g, respectively, while dry weights were 184.92 84.31 g and 179.54 72.85 g. Formalin-fixed pterygium tissue revealed a slightly higher percentage of NPTM than non-fixed pterygium tissue (69.39 13.29% vs. 67.75 13.29%, p = 0.792), but this difference was not statistically significant. The freeze-dried method can be utilised to quantify the NPTM of pterygium fibrovascular tissue and investigate the influence of pterygium translucency on predicting induced-corneal astigmatism

Utilization of Anterior Segment Optical Coherence Tomography Enhanced High Resolution Corneal In Measuring Pterygium Thickness

Introduction: As various pterygium morphologies have been advocated as contributing factor on corneal astigmatism, little support in the literature available in establishing techniques in measuring pterygium thickness as clinical indicator.Objective: The aim of this study was to describe a quantitative method in determining pterygium thickness using anterior segment optical coherence tomography (AS-OCT).Methods: Anterior segment imaging was performed using enhanced high resolution cornea (EHRC) of Visante™ AS-OCT in 120 primary pterygium eyes. Prior to imaging, corneal topography assessment was performed on each pterygium eye in order to identify its topographic location. Based on topography mapping, three meridians (in degrees) were selected as close as possible to the pterygium border, which signify the demarcation of pterygium from the cornea. Reliability testing between intra and inter-observer of AS-OCT imaging modality was examined using intraclass correlation and scatter plot.Results: The overall (n = 120) mean and standard deviation of pterygium thickness EHRC of AS-OCT modality were 0.48 ± 0.10 mm (confidence interval: 0.45 – 0.50). EHRC of AS-OCT also showed excellent intra and intergrader reliability in measuring pterygium thickness with intraclass correlation of 0.997 (confidence interval: 0.994 – 0.998).Conclusions: EHRC of AS-OCT imaging modality is a better choice in assessing pterygium compared to traditional slit-lamp biomicroscopy. This tool is applicable for future work related to better understanding on the role thickness in pterygium morphology, its progression and prediction of induced corneal astigmatism and visual impairment due to pterygium

Corneo-pterygium total area measurements utilising image analysis method

Purpose: To describe an objective method to accurately quantify corneo-pterygium total area (CPTA) by utilising image analysis method and to evaluate its association with corneal astigma- tism (CA). Methods: 120 primary pterygium participants were selected from patients who visited an oph- thalmology clinic. We adopted image analysis software in calculating the size of invading pterygium to the cornea. The marking of the calculated area was done manually, and the total area size was measured in pixel. The computed area is defined as the area from the apex of pterygium to the limbal-corneal border. Then, from the pixel, it was transformed into a per- centage (%), which represents the CPTA relative to the entire corneal surface area. Intra- and inter-observer reliability testing were performed by repeating the tracing process twice with a different sequence of images at least one (1) month apart. Intraclass correlation (ICC) and scatter plot were used to describe the reliability of measurement. Results: The overall mean (N = 120) of CPTA was 45.26 ± 13.51% (CI: 42.38-48.36). Reliability for region of interest (ROI) demarcation of CPTA were excellent with intra and inter-agreement of 0.995 (95% CI, 0.994-0.998; P < 0.001) and 0.994 (95% CI, 0.992-0.997; P < 0.001) respectively. The new method was positively associated with corneal astigmatism (P < 0.01). This method was able to predict 37% of the variance in CA compared to 21% using standard method. Conclusions: Image analysis method is useful, reliable and practical in the clinical setting to objectively quantify actual pterygium size, shapes and its effects on the anterior corneal curvature

Tear ferning: effect of gender and menstrual cycle (Corak pempakisan air-mata: kesan jantina dan kitaran haid)

This study aimed to investigate whether tear ferning (TF) pattern is affected by gender and the menstrual cycle. The first phase of this study investigated if there were any TF pattern differences between genders. The second phase of this study investigated the changes in TF pattern during the menstrual cycle. For each subject, 10 microliters of tear fluid was collected and dropped onto a microscope slide using a micro capillary tube and then dried in a temperature and humidity-controlled room i.e., at temperature of 22.9±1.6°C and relative humidity (rH) of 51+1.5%. The dried droplet was divided according to distinct morphological features based on four types according to Rolando’s classification of TF patterns. For the first phase of the study we found no significant changes in TF pattern between genders. We found that approximately 37.5% (N=30) of our study population obtained TF pattern of type II. Type III consisted of 21 subjects (26.3%) while type IV consisted of 17 subjects (21.2%). The least number of TF patterns observed was type I (N=12, 15.0%). The majority of our subjects obtained TF pattern of type II whereas the type I pattern was found in the least number of subjects. For the second phase of our study Type II pattern was the most frequently recorded during the “in-between menstruation” visit. However, Types III and IV were more frequently recorded during “menstruation”; ANOVA showed a significant difference in TF pattern during “menstruation” and “in-between menstruation” (p<0.001) visits. This study showed no clinically significant difference in TF pattern between genders, implying that both genders of our sample generally have a similar risk of developing dry eye. However, since there was a significant difference in the TF pattern during the menstrual cycle, there appears to be an increased risk of a female patient developing dry eye during menstruation because of the prevalence of Types III and IV TF patterns found during menstruation

Visual status following contact lens related microbial keratitis

Introduction: A hospital based case control study was conducted in government hospitals on contact lens patients diagnosed with microbial keratitis. Methods: The objective of this study is to determine the visual outcomes of contact lens related microbial keratitis. The visual outcomes which comprised of visual acuity, keratometry readings, corneal topography findings and contrast sensitivity examinations was determined after three months from the first presentation at the hospitals. Results: The mean LogMAR visual acuity during presentation was 0.96 ± 0.73 or a Snellen equivalent 6/60 (n=76) and mean LogMAR visual acuity after three months was 0.10 ± 0.48 or a Snellen equivalent 6/7.5 (n=76) with a significant difference (t=11.22, df=78, p=0.001). Best fit curve for the cases had a regression coefficient, r=0.350 ± 0.063 (95% CI = 0.224, 0.447, df=78, p=0.001. The visual acuity in cases and controls was 0.10 ± 0.48 and -0.10 ± 0.14 respectively (t= -3.61, df=154 p=0.001) after three months which showed improvement. There was a reduction in the corneal uniformity index and corneal asphericity in the cases. The Corneal Uniformity Index (CU index) in cases was 63.03 ± 26.38 (n=76) and in controls, 80.13 ± 11.30 (n=77), (t= -5.22, df=151, p=0.001). There was also a reduction in the contrast sensitivity function at all spatial frequencies in the cases which was significantly different. Conclusion: Microbial keratitis reduced the vision, corneal uniformity index, asphericity and contrast sensitivity after three months in eyes of patients diagnosed with the condition

Risk factors associated with contact lens related microbial keratitis

Introduction: Microbial keratitis is one of the most challenging complications of contact lens (CL) wear. Proper CL practice plays an important role to reduce the risk for contact lens related microbial keratitis (CLRMK). Methods: This multi-centre case-control study was conducted from January 2008 until June 2009 to determine the risk factors associated with CLRMK. Cases were defined as respondents who were treated for CLRMK, whilst controls were respondents who were contact lens wearers without microbial keratitis. Ninety four cases were compared to 94 controls to determine the risk factors for CLRMK. Results: The predictors for CLRMK were: Not washing hands with soap before handling CL (aOR 2.979, CI 1.020, 8.701 p=0.046), not performing rubbing technique whilst cleaning the CL (aOR 3.006, CI 1.198, 7.538 p=0.019) and, not cleaning the lens case with multipurpose solution daily (aOR 3.242 CI 1.463, 7.186 p=0.004). Sleeping overnight with the CL in the eye (aOR 2.864, CI 0.978, 8.386 p=0.049) and overall non-compliance with lens care procedures (aOR 2.590, CI 1.003, 6.689 p=0.049) contributed significantly to CLRMK. Conclusion: Health education and promotion in contact lens care are important and should be conducted by eye care practitioners to reduce the occurrence of CLRMK

Changes in contrast sensitivity in young adults with diabetes

Background: This study compared contrast sensitivity and visual acuity of young adults with diabetes to that of controls and attempted to identify predictors of dry eye symptoms in patients with diabetes. Methods: This cross-sectional study, which included 37 patients with diabetes and 37 controls, was conducted in the Optometry Clinic of Kulliyyah Allied Health Science. All participants were aged between 19 and 39 years. Inclusion criteria were a diagnosis of diabetes without any evidence of ocular disease, abnormalities in colour vision or media opacity. Results: The contrast sensitivity significantly differed between patients and controls (p = 0.045). A multiple regression analysis showed that contrast sensitivity was a significant predictor of ocular symptoms in patients with diabetes, and this was statistically significant (p = 0.002). Conclusions: Contrast sensitivity may be affected during early ocular changes among young adults with diabetes. It may also predict the occurrence of dry eye symptoms in such patients

Risk factors for contact lens related microbial keratitis

Background: Contact lens related microbial keratitis (CLRMK) is a complication of contact lens wear and is sight threatening. A hospital case control study was conducted to determine the risk factors for CLRMK in patients with CLRMK in government hospitals in the Klang Valley. Materials and Methods: All patients who presented with CLRMK (n=94) at the hospitals were selected as cases and controls (n=94) were taken from contact lens users without CLRMK. Self administered questionnaire in Bahasa Malaysia was used to collect data on socio-demographics, contact lens characteristics, personal habit and contact lens care procedures. Data was analysed using SPSS 16. Results: The most common causative agent was Pseudomonas aeruginosa. Chinese ethnicity (aOR 0.126, CI 0.045, 0.355 p=0.001) and Indian ethnicity (aOR 0.295, CI 0.088, 0.989 p=0.048) had decreased risks for CLRMK while Malay ethnicity was a predictor for CLRMK with an increased risk of 70%-87%. Non-compliance to lens care procedures contributed to an increased risk of 2.6 times for CLRMK (aOR 2.590, CI 1.003, 6.689 p=0.049). Not washing hands with soap (aOR 2.98, CI 1.02, 8.70 p=0.046), not performing rubbing technique (aOR 3, CI 1.19, 7.54 p=0.019) and not cleaning lens case with multipurpose solution (aOR 3.24, CI 1.46, 7.19 p=0.004) were identified as predictors for CLRMK. Conclusion: The risk of CLRMK is increased in Malays and in non-compliant wearers

Reliability of pterygium redness grading software (PRGS) in describing different types of primary pterygia based on appearance

The aim of this study was to evaluate the reliability of Pterygium Redness Grading Software (PRGS) in describing different types of primary pterygia. Ninety-three participants with primary pterygia who visited an ophthalmology clinic were recruited in this study. PRGS is a semi-automated computer program used to measure fibrovascular pterygium redness by analysing digital images of the pterygium and grading it on a continuous scale of 1 (minimum redness) to 3 (maximum redness). An ocular surface expert graded all 93 images in random order. The reliability of PRGS was determined by comparing pterygium redness measured using the software and by the expert. The mean and standard deviation of redness of the pterygium fibrovascular images measured using PRGS and by the expert were 1.81 ± 0.58 and 1.73 ± 0.61, respectively (P = 0.396). A comparative analysis based on pterygium type showed an increase in redness according to pterygium type (Type I: 1.43 ± 0.32; Type II: 1.67 ± 0.55; and Type III: 2.31 ± 0.46), without significant differences compared to redness measured by the expert (Type I: 1.38 ± 0.34; Type II: 1.78 ± 0.62; and Type III: 2.02 ± 0.66) (all P > 0.05). PRGS could describe and classify pterygia according to their redness, and PRGS-based classification was in agreement with the established classification of pterygia. Therefore, PRGS can be used in addition to the existing pterygium grading system