Effect of artificial tears on dynamic optical quality in patients with dry eye disease

Background : In clinical practice, fluctuating vision or decreased quality of vision is a common complaint in dry eye patients. Our study was designed to investigate the change in dynamic optical quality in dry eye patients after the use of artificial tears. Methods : Fifty-nine patients with dry eye disease (DED) and 31 healthy age- and sex-matched control subjects were included in this prospective case-control study. Clinical evaluation of the ocular surface included Ocular Surface Disease Index (OSDI), tear film break-up time (TBUT), lipid layer thickness (LLT), and Schirmer I test. DED patients were divided into two groups, mild (31 patients) and severe (28 patients). The optical quality of the tear film was measured with the Optical Quality Analysis System (OQAS) using the mean objective scatter index (mean OSI), standard deviation of objective scatter index (SD-OSI) and modulation transfer function cut-off (MTF cut-off). After baseline examinations, one drop of artificial tears (ATs, carboxymethylcellulose ophthalmic solution, 0.5%) was instilled in both eyes, and optical quality parameters were measured again at 5 and 30 minutes following application of ATs. Results: At baseline, the mean OSI was higher in the DED group (0.95 ± 0.54) than in controls (0.54 ± 0.23, P <0.001). The SD-OSI was also significantly increased in DED patients (0.44 ± 0.71) compared to control subjects (0.12 ± 0.06, P =0.003). Five minutes after AT instillation, mean OSI and SD-OSI decreased significantly in severe DED patients (P =0.044; P =0.018), remained unchanged in mild DED patients, and increased in the control group ( P =0.019; P <0.001). Thirty minutes after AT instillation, no significant difference in optical quality parameters was observed among the three groups. Conclusion : The effect of ATs on optical quality in patients with DED may differ according to the severity of the disease. Measurement of optical quality might be a promising tool to evaluate the effects of various ATs and possibly individualize treatment in DED patients.

Effect of artificial tears on aqueous deficient dry eye, a dynamic optical study

Background: To investigate the change of dynamic optical quality in aqueous deficient dry eye (ADDE) patients after the use of artificial tears.Methods: Fifty-nine patients with ADDE and 31 healthy age- and sex-matched control subjects were included in this prospective case-control study. Clinical evaluation of the ocular surface included Ocular Surface Disease Index (OSDI), tear film break-up time (TBUT), lipid layer thickness (LLT), and Schirmer I testing. ADDE patients were divided into two groups, mild (31 patients) and severe (28 patients). The optical quality of the tear film was measured with the Optical Quality Analysis System (OQAS) using the mean objective scatter index (mean OSI), standard deviation of objective scatter index (SD-OSI) and modulation transfer function cut-off (MTF cut-off). After baseline examinations, one drop of artificial tears (ATs, carboxymethylcellulose ophthalmic solution, 0.5%) was instilled in both eyes, and optical quality parameters were measured again at 5- and 30-minutes following application of ATs.Results: At baseline, the mean OSI was higher in the ADDE group (0.95 ± 0.54) than in controls (0.54 ± 0.23, P<0.001). The SD-OSI was also significantly increased in ADDE patients (0.44 ± 0.71) compared to control subjects (0.12 ± 0.06, P=0.003). Five minutes after ATs instillation, mean OSI and SD-OSI decreased significantly in severe ADDE patients (P=0.044; P=0.018), was unchanged in mild ADDE patients, and increased in the control group (P=0.019; P<0.001). Thirty minutes after ATs instillation, no significant difference in optical quality parameters was observed for the three groups.Conclusion: The effect of ATs on optical quality in patients with ADDE may differ according to the severity of the disease. Measurement of optical quality might be a promising tool to evaluate the effects of various ATs and possibly individualize treatment in ADDE patients.

Intraocular light scatter in patients on topical intraocular pressure–lowering medication

Purpose: To quantify ocular light scattering in patients under treatment with intraocular pressure–lowering eye-drops. Methods: In this prospective, observational, cross-sectional case series study, 160 eyes of 160 patients with primary open angle glaucoma or primary ocular hypertension were consecutively recruited from our Glaucoma Department over 7 months. In total, 46 eyes of 46 healthy volunteers matched for age and sex served as the control group. The variables recorded in a single visit were as follows: drug and number of drops per day, treatment duration, OXFORD corneal staining grade, lower tear meniscus height as measured by spectral domain optical coherence tomography, ocular redness and non-invasive tear breakup time measured with the Oculus Keratograph 5M, ocular surface disease index questionnaire score and objective scatter index through a double-pass technique (Optical Analysis System II). Results: Objective scatter index was higher in the patient group (3.1, interquartile range = 1.8–5.47) than in the control group (1.95; interquartile range = 0.7–5; p = 0.017). In a multiple linear regression model, non-invasive tear breakup time was identified as the most influential variable on light scatter (mean ratio = −1.015; p = 0.003; 95% confidence interval = −1.025 to −1.005). No correlation with objective scatter index was observed for number of daily eye-drops, preservative concentration or treatment duration. Conclusion: Participants on anti-glaucoma medication showed a significantly higher objective scatter index than control group individuals. In the treated patient group, a lower non-invasive tear breakup time was associated with a higher objective scatter index. This suggests that lubricating eye-drops to improve tear breakup time could also improve vision quality in these patients by diminishing light scattering.