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

A prospective contralateral eye comparison of the tolerability of two artificial tears with different physical properties in patients with dry eye disease

Background: Artificial tears (ATs) are widely used in ophthalmic practice with various formulations, mainly as a treatment for dry eye, owing to their rapid ability to alleviate the signs and symptoms of this condition. We aimed to investigate drop comfort and subjective ocular symptoms after instillation of the following ATs with different physical properties: Optive® non-preservative (OUD) and Systane® Hydration non-preservative (SHUD). Methods: This was a prospective, double-blind, randomized, contralateral eye comparison study. A rheometer and a digital pH meter were used to evaluate the viscosity and pH of both ATs prior to instillation. We recruited 36 patients with dry eye disease. Single standardized AT volumes were set using a micropipette for all patients. Ocular discomfort was assessed using the Ora Calibra™ Ocular Discomfort and 4-Symptom Questionnaire (OOD4SQ; 0 – 5 scale) before and 60 min after instillation. Drop comfort was assessed using the Ora Calibra™ Drop Comfort Scale (0 – 10 scale) immediately after AT instillation. The difference in the drop comfort score (DCS) between the two ATs and ocular discomfort scores using OOD4SQ before and 60 min after instillation of each AT were recorded and compared. Results: The viscosities and pH of SHUD and OUD were 32.73 centipoise (cP) and 7.74 and 14.42 cP and 7.19, respectively. The mean (standard deviation) DCS was higher in the SHUD group than in the OUD group (1.83 [1.21] versus 1.67 [1.12]); however, the difference was not statistically significant (P > 0.05). There was a significant reduction in all parameters of OOD4SQ including overall discomfort, burning, dryness, grittiness, and stinging 60 min after OUD instillation (all P < 0.05), while a significant difference was only noted in dryness (P < 0.05) in the SHUD group. Conclusions: OUD, which has a lower viscosity and pH compared to SHUD, provides less subjective sensation and better ocular comfort 60 min after instillation. Further randomized clinical trials including patients with dry eye disease of different severities, larger sample sizes, and longer follow-up periods are required to verify our findings

Prevalence of Diabetic Retinopathy (DR) and its associated factors among diabetes patients in Primary Care Clinics, Kuantan, Pahang

Introduction: Diabetic retinopathy (DR) is one of the commonest complications of diabetes mellitus. This study was to determine the prevalence of diabetic retinopathy and its association with chronic kidney disease (CKD), high HbA1c and dyslipidemia among diabetic patients in government primary care clinics. Methods: A cross sectional study was carried out. The respondents were selected from diabetic registry at two government primary care clinics in Kuantan, Pahang via stratified random sampling method during the study period from May 2010 to April 2011. The respondents were interviewed and assessed clinically using a structured questionnaire. Retinal examination was performed by accredited staff using non-mydratic retinal imaging and DR was classified according to the International Clinical Diabetic Retinopathy Disease Severity Scale. Results: Out of 400 respondents, 58.8% diagnosed diabetes less than 5 years and 51.0% had uncontrolled blood pressure (>130/80 mmHg). The prevalence of diabetic retinopathy and maculopathy were 33.5% and of 17.8% respectively. Most of these patients (22.3%) had mild non-proliferative diabetic retinopathy. DR-patients had higher percentages of chronic kidneys disease (17.9% vs. 6.8%; p<0.001) and a higher mean of HbA1C (8.69 vs. 8.11; p=0.015)compared to non-DR patients. The study revealed that DR was independently associated with chronic kidney disease {OR: 3.46, 95% CI (1.76, 6.80)} and high HbA1c {OR: 1.12, 95% CI (1.02, 1.23)}. Those with dyslipidemia however, has 39% less risk of diabetic retinopathy {OR: 0.61, 95% CI (0.39, 0.94)}. Conclusion: This study shows that diabetic patients with CKD and high HbA1c have greater risks to develop diabetic retinopathy but has protective risk with dyslipidemia

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

Fibrovascular redness grading using Gaussian process regression with radial basis function kernel

Information obtained from redness grading can assist clinician for diagnosis and in making clinical decision. This research work aims to mimic human perception of fibrovascular redness using features extracted from color entropy. Gaussian process regression with the radial basis function kernel has been employed to fuse relevant features and established the model of redness perception. In this paper, we present the results of the radial basis function kernel incorporated as the covariance function in the GPR as the scale, sigma is varied

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

Validation of IVCM in measuring sub-basal nerve plexus and keratocyte cell density in corneal wound healing

Introduction: This study aimed to evaluate the reliability measurement of corneal stromal thickness, sub-basal nerve plexus (SBNP) and keratocyte cell density (KCD) in laser refractive surgery patients. Methods: 120 eyes of 60 participants were recruited and both right and left eyes of the myopic subjects were measured separately. Cornea stromal thickness were measured based on the cellular morphology that differs between each corneal layer. Measurement of SBNP and KCD were done using in-vivo confocal microscopy (IVCM) using corneal stromal thickness as reference. Corneal nerve parameters measured includes nerve fiber density (NFD), nerve branch Density (NBD) and nerve fiber length (NFL) while KCD were measured based the amount per area, depending on the region of interest. All images were captured and processed using ImageJTM Software and NeuronJ. All data were expressed in mean and standard deviation. Statistical analyses were performed using Predictive analytics software. P < 0.05 was set as the level of significance. Intra- and inter-observer intraclass correlation analysis were done to evaluate reliability of measurement in corneal stromal thickness, SBNP and KCD. Results: This study found no significant difference between measurements for corneal stromal thickness, SBNP and KCD measured. (All P > 0.05). Intraclass correlation analysis showed both intra- and inter-observer performance were approximately consistent and reliable (All r > 0.90, P > 0.05). Conclusion: Measurement of corneal stromal thickness, SBNP and KCD using IVCM is valid and reliable

Effects of artificial tears on keratocyte cell density after femtosecond laser in situ keratomileusis: a prospective, comparative, interventional, contralateral eye study

Background: Flap creation during laser refractive surgery restructures the anterior cornea, particularly the stroma, reducing the keratocyte cell density (KCD). This reduced density makes it challenging to completely regenerate to the presurgical phase. The aim of the present study was to investigate the effects of two types of artificial tear (AT) interventions on KCD up to 3 months after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) surgery. Methods: This prospective, double-blind, comparative, interventional, contralateral eye study recruited patients with myopia scheduled for FS-LASIK. Inclusion criteria were healthy individuals aged 19 – 25 years with moderate or high myopia, a maximum cylindrical error of - 1.25 diopters, and a maximum pupil size of 6.5 mm who had undergone FS-LASIK and completed 3 months of follow-up. Complete optometric and ophthalmologic examinations were performed. Bilateral simultaneous FS-LASIK surgery was performed using the same femtosecond laser platform as in the standard procedure. The Research Randomizer was used to determine the eye to be treated with Systane® Hydration (Alcon Laboratories, Inc., Fort Worth, TX, USA) or Systane® ULTRA (Alcon Laboratories, Inc., Fort Worth, TX, USA) AT. KCD was examined using real-time images obtained from in vivo confocal microscopy (Heidelberg Retina Tomograph 3 with the Rostock Cornea Module, HRT III RCM); Heidelberg Engineering GmbH, Heidelberg, Germany) at baseline and 1- and 3-month postoperative visits. Results: We included 60 eyes of 30 participants with a mean (standard deviation) age of 21.34 (1.85) years and a male-to-female ratio of 1:1 who completed 3-month post-FS-LASIK surgery follow-up. KCD did not differ significantly between the two groups at any visit (all P &gt; 0.05); nevertheless, mean KCD was initially reduced up to 1 month postoperatively and then revealed a slight increase up to 3 months postoperatively in Systane® Hydration-treated eyes and continued to reduce in Systane® ULTRA-treated eyes. Intragroup comparisons revealed that the eyes treated with ATs experienced a significant reduction in KCD between the preoperative and 1-month postoperative visits and between the preoperative and 3-month postoperative visits (all P &lt; 0.05). Treatment-related complications were not observed. Conclusions: Overall, KCD reduced up to 3 months post-FS-LASIK surgery. Both AT types exerted a comparable effect on postoperative KCD up to 3 months. Future studies with a more frequent administration of ATs, longer follow-up periods, and a control group are required before preliminary outcomes of the present study can be generalized

Association of net pterygium tissue mass (dryweight) in determining changes in oculovisual functions and anterior corneal curvature relative to pterygium types

Introduction: Dryweight in pterygium is more towards the fleshy appearance of the fibrous tissue. Aim: The goal of this study was to determine the predictive ability of net pterygium tissue mass (dryweight) on predicting changes in anterior corneal cur-vature and oculovisual functions relative to pterygium types. Methodology: A total of 93 primary pterygium patients who visited an ophthalmology clinic were selected as participants. The net pterygium tissue mass were obtained via freeze dry method sub-sequent to pterygium excision using fibrin glue adhesive method. Best corrected visu-al acuity (BCVA) and contrast sensitivity function (CSF) were measured by using M&S Smart System II as measurement for oculovisual function, while the changes of ante-rior corneal curvature was measured using corneal topography. Results: The mean and standard deviation for BCVA, CSF and SimK were 0.44 ± 0.30 LogMAR, 24.28 ± 17.66 % and 4.64 ± 4.18 D respectively. This study found that the predictive ability of pterygium dryweight with BCVA were strong in Type I and Type III while moderate in Type II with 13.10% (R2 = 0.131, p < 0.05) in Type I. Slight increase trend were noted in both Type II with 53% (R2 = 0.530, p < 0.05) and Type III, with 21.60% (R2 = 0.216, p < 0.05). For CSF, the predictive ability of pterygium dryweight were strong in all types with Type I, Type II and III reported 21.6% (R2 = 0.216, p < 0.05), 31.8% (R2 = 0.318, p < 0.05), 28.9% (R2 = 0.289, p < 0.05) respectively. The predictive ability of pterygium dry-weight for SimK were strong in all types with contribution of 44.7% (R2 = 0.447, p < 0.05), 47.7% (R2 = 0.477, p < 0.05), 39.1% (R2 = 0.391, p < 0.05) respectively. Conclusion: Net pterygium tissue mass (dryweight) is a strong factor in predicting changes of ocu-lovisual functions and anterior corneal curvature in relation to pterygium types