Combination of hyaluronic acid, carmellose, and osmoprotectants for the treatment of dry eye disease.

BACKGROUND: Dry Eye Disease (DED) is a multifactorial disease, with a high prevalence, that can have a great impact on the quality of life of patients. The first step of treatment includes the use of lacrimal substitutes composed of polymers, possible to associate osmoprotectant agents to the lacrimal substitutes. The aim of this article is to analyze the properties of the combination of hyaluronic acid (HA), carmellose, and osmoprotectors (Optava Fusion®; Allergan, Inc., Irvine, CA, USA) on DED. General considerations on the use of artificial tears are also proposed. METHODS: A group of ophthalmologists, experts in the management of the ocular surface, analyzed different aspects related to DED; among them, the use of artificial tears in general and the properties of the combination of HA, carmellose, and osmoprotectors, in particular, were discussed. A review of the literature was carried out, which included different articles published in Spanish, English, and French until April 2017. CONCLUSIONS: DED is a common chronic pathology that usually requires sustained treatment. In addition, the combination of HA, carmellose, and osmoprotectors has proven to be effective in the treatment of symptoms and signs of dry eye by the synergistic action of all its components. This review provides key elements to help ophthalmologists who begin in the management of DED.

Impact of herpetic stromal immune keratitis in corneal biomechanics and innervation.

PURPOSE: To study corneal innervation in eyes with history of herpetic keratitis and its correlation with corneal sensitivity and biomechanical properties. METHODS: A total of 56 eyes were included, of which 16 had a history of unilateral immune stromal herpetic keratitis, 16 were their contralateral eyes, and 20 were healthy controls. Structural analysis of corneal nerve plexus was performed by confocal microscopy. Biomechanical properties were measured with the Ocular Response Analyzer. Corneal sensitivity was assessed by contact (Cochet-Bonnet) and non-contact (Belmonte) esthesiometry. RESULTS: The eyes with a history of herpetic keratitis had reduced sensitivity for mechanical stimuli when compared to healthy eyes (1441.88 ± 83 ml/min vs. 67.9 ± 7.86 ml/min). Nerve fiber density in the corneas with a history of herpetic disease was lower (4.13 ± 2.19 U/image) than in the contralateral eyes (7.44 ± 2.9 U/image, p value = 0.01) and than in healthy controls (10.35 ± 2.01, p value < 0.0001). The best structural and functional correlation was established between the total length of nerves per section and mechanic threshold assessed by Belmonte esthesiometer (Coef. -0.58 p value < 0.0001) and between total length of nerves and corneal resistance factor (CRF) (Coef. -0.64, p value < 0.0001). CONCLUSIONS: The corneal sensitivity impairment in eyes with immune stromal herpetic keratitis can be explained by the loss of nerve fibers. Biomechanical corneal properties are affected as well. Corneal hysteresis (CH) and CRF are lower for the eyes with a history of herpetic keratitis, and also for the contralateral eye when compared to healthy controls.

Optical quality and intraocular scattering assessed with a double-pass system in eyes with contact lens induced corneal swelling.

PURPOSE: To evaluate the impact of contact lens (CL)-induced corneal swelling on the optical quality of the eye by means of the double-pass technique. METHODS: Measurements of 6 healthy subjects were obtained in 5 visits over 1 week, at baseline and after sleeping with 4 different CLs of +0.50 D, +2.00 D, +5.00 D and +8.00 D (Acuvue2), randomly fitted on 4 different days. The control eye wore no CL. Corneal pachymetry and optical quality of the eye (OQAS, Visiometrics) were measured once at baseline and at three interval times in the follow-up visits: immediately after CL removal, and 1 and 2 h after CL removal. Optical quality was evaluated by means of the Strehl ratio and OQAS values at 100%, 20% and 9% contrasts. Intraocular scattering was evaluated with the objective scatter index (OSI). RESULTS: Mean overnight swelling was 5.98 ± 4.29% in CL-eyes versus 0.30 ± 0.78% in control eyes (p < 0.01). Corneal swelling was maximal immediately after CL removal and decreased with time (p < 0.01). A significant worsening in all optical quality parameters and a significant increase of the OSI were found in eyes with corneal swelling (p < 0.05). Two hours after CL removal there were no statistically significant differences (p > 0.05) between CL-eyes and control eyes in any of the measured parameters. CONCLUSIONS: Corneal swelling has a significant impact on the optical quality of the eye and on intraocular scattering as assessed with the double-pass technique.

Refractive stabilization and corneal swelling after cataract surgery.

PURPOSE: To determine the earliest time after cataract surgery when corneal swelling and automated refraction are stabilized sufficiently to allow reliable refractive prescription. METHODS: This was a prospective, nonrandomized, case series study of 124 consecutive eyes undergoing uneventful cataract surgery. Automated refraction and central corneal thickness (CCT) measurements were made at baseline before cataract surgery and on follow-up visits 1 day and weekly for 4 weeks afterward. Corneal swelling was determined as the percentage change in CCT after surgery. To determine the validity of automated refraction, it was compared with subjective refraction at the final visit. RESULTS: Corneal swelling decreased between the first postsurgical day and the first week and again between postsurgical weeks 1 and 2 (p < 0.01 each). Although thinning continued through the fourth postsurgical week, the changes were not significant. Both spherical and cylindrical refraction were stable 1 week after surgery, with the greatest change between the first postsurgical day and 1 week (p < 0.01). In replicate measurements of automated spherical refraction taken on the last visit, the intraclass correlation coefficient was 0.93. For automated cylindrical refraction, it was 0.81. CONCLUSIONS: Automated refraction is highly repeatable and can be used to monitor postsurgical refractive changes. Whereas corneal swelling becomes stable 2 weeks after cataract surgery, automated refraction becomes stable after 1 week and can be used to accurately prescribe corrective lenses at that time.

Repeatability and agreement of ARK-30 autorefraction after cataract surgery.

BACKGROUND: To evaluate the intra-test variability of ARK-30 handheld autorefractor and the agreement with subjective refraction and retinoscopy after uneventful cataract surgery. DESIGN: Prospective and non-randomized study that included 6 visits by patients undergoing uneventful cataract surgery at IOBA (Instituto de Oftalmobiología Aplicada) Eye Institute (University of Valladolid). PARTICIPANTS: The mean age of the 79 patients was 66.5years (range 23-90years). For the 124 eyes, the mean spherical equivalent of the sample at baseline visit was -3.59±6.28D (range -21.00D to +4.44D). METHODS: Automated refraction was performed on follow-up visits 1day and weekly for 4weeks. Retinoscopy and subjective refraction were conducted at the Week 4 follow up. MAIN OUTCOME MEASURES: Automated refraction. RESULTS: Sphere, cylinder and mean spherical equivalent, J(0) and J(45) coefficient variabilities were low in all visits. Standard deviations and the limits of agreement were smallest for the last visit. Subjective refraction sphere and cylinder values were more positive than autorefraction by 0.12±0.53D (P=0.031) and 0.23±0.42D (P<0.001), respectively. Comparison between autorefraction and retinoscopy showed a similar trend with the sphere and cylinder differences, 0.32±0.77D and 0.38±0.43D (P<0.05), respectively. CONCLUSIONS: The ARK-30 is sufficiently accurate and repeatable for automated refraction after uneventful cataract surgery. This instrument may be useful for monitoring refractive outcome in these patients.