Felipe Valenzuela

The Matrix Metalloproteinase 9 Point-of-Care Test in Dry Eye

Dry eye is a common, multifactorial disease currently diagnosed by a combination of symptoms and signs. However, the subjective symptoms of dry eye poorly correlate to the current gold standard for diagnostic tests, reflecting the need to develop better objective tests for the diagnosis of dry eye. This review considers the role of ocular surface matrix metalloproteinase 9 (MMP-9) in dry eye and the implications of a novel point-of-care test that measures MMP-9 levels, InflammaDry (RPS, Sarasota, FL) on choosing appropriate therapeutic treatments.

Dynamics of tear fluid desiccation on a glass surface: a contribution to tear quality assessment

BackgroundFern-like crystalloids form when a microvolume of tear is allowed to dry out at ambient conditions on a glass surface. Presence of crystalloids in tear “microdesiccates” is used to evaluate patients with Dry-Eye disease. This study aims to examine morphologically the desiccation process of normal tear fluid and to identify changes associated with accelerated tear evaporation. Tear microdesiccates from healthy (Non-Dry Eye) and Dry Eye subjects were produced at ambient conditions. Microdesiccate formation was monitored continuously by dark-field video microscopy. Additionally, accelerated desiccation of tear samples from healthy subjects was conducted under controlled experimental conditions. Particular morphological domains of tear microdesiccates and their progressive appearance during desiccation were compared.ResultsIn normal tear microdesiccates, four distinctive morphological domains (zones I, II, III and transition band) were recognized. Stepwise formation of those domains is now described. Experimentally accelerated desiccation resulted in marked changes in some of those zones, particularly involving either disappearance or size reduction of fern-like crystalloids of zones II and III. Tear microdesiccates from Dry Eye subjects may also display those differences and be the expression of a more synchronous formation of microdesiccate domains.ConclusionMorphological characteristics of tear microdesiccates can provide insights into the relative rate of tear evaporation.

Stratification of Tear Components During Tear Microdesiccation on Vertical Glass Surfaces: A Novel Approach in Tear Fluid Assessment.

Purpose: Tear desiccation on a horizontal glass surface followed by low-resolution light microscopy has been used as an expeditious diagnostic aid to evaluate patients suspected of dry eye. The presence of fern-like crystalloids in the dry specimen is the only feature taken into consideration. We demonstrate that different morphological domains of tear microdesiccates can be separated based on distinctive physicochemical properties. Methods: Healthy subjects (Ocular Surface Disease Index questionnaire, laboratory tests, and slit-lamp examination) and 74 young adults from a random student population were recruited as volunteer tear donors. Single tear samples were taken from individual eyes (n = 154) using absorbing polyurethane minisponges. From each sample, aliquots were allowed to desiccate simultaneously on microscope slides positioned either horizontally or vertically followed by comparative dark-field microscopy. Results: Vertical desiccation of each tear sample resulted in highly reproducible top-to-bottom stratification. Particular layers in any vertical microdesiccate represented morphological domains of the corresponding horizontal microdesiccate. Major fern-like crystalloids located at the center of Rolando type I horizontal microdesiccates became concentrated in a prominent layer at the bottom of vertical microdesiccates. Often, these fern-like crystalloids were more vigorous than those of the horizontal counterpart. A number of tear samples from the random population showed no ability to form fern-like crystalloids either by vertical or horizontal microdesiccation. Other prominent layers in vertical microdesiccates represented less noticeable circularly distributed morphological domains of the corresponding horizontal specimens. Conclusions: Microdesiccation of tear fluid on a vertical glass surface causes top-to-bottom stratification of diverse tear components. A more comprehensive expeditious tear assessment is feasible.

Progress in tear microdesiccate analysis by combining various transmitted-light microscope techniques

BackgroundTear desiccation on a glass surface followed by transmitted-light microscopy has served as diagnostic test for dry eye. Four distinctive morphological domains (zones I, II, III and transition band) have been recently recognized in tear microdesiccates. Physicochemical dissimilarities among those domains hamper comprehensive microscopic examination of tear microdesiccates. Optimal observation conditions of entire tear microdesiccates are now investigated. One-μl aliquots of tear collected from individual healthy eyes were dried at ambient conditions on microscope slides. Tear microdesiccates were examined by combining low-magnification objective lenses with transmitted-light microscopy (brightfield, phase contrasts Ph1,2,3 and darkfield).ResultsFern-like structures (zones II and III) were visible with all illumination methods excepting brightfield. Zone I was the microdesiccate domain displaying the most noticeable illumination-dependent variations, namely transparent band delimited by an outer rim (Ph1, Ph2), homogeneous compactly built structure (brightfield) or invisible domain (darkfield, Ph3). Intermediate positions of the condenser (BF/Ph1, Ph1/Ph2) showed a structured roughly cylindrical zone I. The transition band also varied from invisibility (brightfield) to a well-defined domain comprising interwoven filamentous elements (phase contrasts, darkfield).ConclusionsImaging of entire tear microdesiccates by transmitted-light microscopy depends upon illumination. A more comprehensive description of tear microdesiccates can be achieved by combining illumination methods.

Delayed-onset postoperative endophthalmitis secondary to Exophiala.

Exophiala is a genus of slow-growing, melanin-producing, saprophytic fungi most commonly found in soil, faeces and decaying plant matter. It is an unusual fungal pathogen capable of causing a variety of ophthalmic manifestations, including keratitis, scleritis and endophthalmitis. In this report, we present a rare case of delayed-onset postoperative endophthalmitis confined to the anterior segment, secondary to Exophiala species. Previous reported cases of delayed-onset postoperative endophthalmitis have been treated medically, with suboptimal outcomes. Our experience supports the use of anterior segment surgery to clear the nidus of disease combined with intravitreal voriconazole to prevent recurrence of the infection.

Ocular Surface Parameters Predicting Patient Satisfaction After a Single Vectored Thermal Pulsation Procedure for Management of Symptomatic Meibomian Gland Dysfunction

Purpose: To evaluate the ocular surface parameters that could predict patient satisfaction after single application of vectored thermal pulsation (VTP). Methods: This is a retrospective interventional case series; it included consecutive patients who underwent bilateral VTP for management of symptomatic meibomian gland dysfunction (MGD). Patients received a full ocular surface evaluation. The outcome was patient subjective improvement during the first 3–4 months after 3 follow-up visits. For analysis, patients were divided into responders and nonresponders. Results: Forty-nine patients received bilateral treatment, with 32 patients (65.3%) reporting subjective improvement after treatment. Responders had lower tear production (6.9 ± 5.9 mm vs. 13.6 ± 6.8 mm; t test P = 0.002), a higher corneal staining score (4.4 ± 5.0 vs. 0.43 ± 1.1; t test P = 0.003), and a higher conjunctival staining score (3.1 ± 2.4 vs. 1.5 ± 1.8; t test P = 0.023) and presented with a higher tear osmolarity (319.7 ± 23.22 mOsm/L vs. 306.9 ± 9.0 mOsm/L; t test P = 0.029) than the nonresponder group. We found no association between patient age, tear breakup time, Ocular Surface Disease Index score, tear lipid layer thickness, or MGD grading score, as measured before intervention, with patient-perceived success of treatment. No complications to treatment were noted, and no patient reported worsening of preexisting symptoms on follow-up. Conclusions: VTP can be effective in treating dry eye symptoms of patients with MGD. Our data show that objective findings of dry eye, as evidenced by lower tear production, higher corneal and conjunctival staining scores, and higher osmolarity, tend to be markers present in the group of patients responding positively to VTP.

Zone I of Tear Microdesiccates Is a Lipid-Containing Structure.

PURPOSE Morphological features of tear microdesiccates on glass surfaces have been associated with tear fluid status. Tear-film lipids play a critical role in the pathophysiology of some ocular surface disorders. Tear microdesiccates display 4 distinctive morphological domains (zones I, II, III, and transition band). In this study, we investigated the lipid location in tear microdesiccates. METHODS Tear from individual healthy eyes (assessed by symptoms, signs, and slit-lamp examination) was collected using absorbing minisponges. One-µL aliquots were allowed to dry under ambient conditions on microscope slides. Tear microdesiccates were examined by various transmitted light microscopy methods. Tear lipids were located both by partition experiments using 2 lipophilic dyes (Oil red O and Nile blue A) mixed with tear fluid under conditions preserving morphological features of microdesiccates and by assessing the effect of 2 solvents markedly differing in polarity (water and ethanol) on the morphology of particular domains of preformed microdesiccates. RESULTS During desiccation, both Nile blue A and Oil red O became preferentially located in the outermost domain of tear microdesiccates (zone I) without affecting the formation of major fern-like crystalloids (zones II and III). Low volumes of water drastically affected fern-like crystalloids, whereas the gross morphology of zone I was maintained. Contrarily, ethanol, a less polar solvent, was a fixative for fern-like crystalloids, although it markedly affected the bulk of zone I by extracting liquid droplets out of microdesiccates and visibilizing some filamentous subcomponents. CONCLUSIONS Zone I is a hydrophobic domain, whereas zones II and III are highly hydrophilic domains of tear microdesiccates. Zone I represents a lipid-rich structure.PURPOSE Morphological features of tear microdesiccates on glass surfaces have been associated with tear fluid status. Tear-film lipids play a critical role in the pathophysiology of some ocular surface disorders. Tear microdesiccates display 4 distinctive morphological domains (zones I, II, III, and transition band). In this study, we investigated the lipid location in tear microdesiccates. METHODS Tear from individual healthy eyes (assessed by symptoms, signs, and slit-lamp examination) was collected using absorbing minisponges. One-µL aliquots were allowed to dry under ambient conditions on microscope slides. Tear microdesiccates were examined by various transmitted light microscopy methods. Tear lipids were located both by partition experiments using 2 lipophilic dyes (Oil red O and Nile blue A) mixed with tear fluid under conditions preserving morphological features of microdesiccates and by assessing the effect of 2 solvents markedly differing in polarity (water and ethanol) on the morphology of particular domains of preformed microdesiccates. RESULTS During desiccation, both Nile blue A and Oil red O became preferentially located in the outermost domain of tear microdesiccates (zone I) without affecting the formation of major fern-like crystalloids (zones II and III). Low volumes of water drastically affected fern-like crystalloids, whereas the gross morphology of zone I was maintained. Contrarily, ethanol, a less polar solvent, was a fixative for fern-like crystalloids, although it markedly affected the bulk of zone I by extracting liquid droplets out of microdesiccates and visibilizing some filamentous subcomponents. CONCLUSIONS Zone I is a hydrophobic domain, whereas zones II and III are highly hydrophilic domains of tear microdesiccates. Zone I represents a lipid-rich structure.

Algorithm approach for revision surgery following late-onset bleb complications after trabeculectomy: long-term follow-up

Purpose: The aim of this study was to introduce a reproducible algorithm for the surgical management of late-onset (>2 months) bleb complications after trabeculectomy with mitomycin C. Methods: We performed a retrospective review of eyes treated using a reproducible algorithm approach by a single surgeon for the surgical management of late-onset bleb complications from July 2006 to April 2014. Exclusion criteria were bleb revision with less than 3 months of follow-up or bleb revision combined with other glaucoma procedures at the time of surgery. Success was evaluated using the Kaplan-Meier survival method and defined as achieving all of the following criteria: primary surgery indication resolved, no additional surgery required for decreasing the intraocular pressure (IOP), and IOP of ≥6 mmHg and ≤18 mmHg. Results: Twenty-three eyes from 20 patients were evaluated. Indications for bleb revision were hypotonic maculopathy (47.8%), bleb leak (30.4%), and dysesthetic bleb (21.7%). The overall primary outcome success rate calculated using the Kaplan-Meier survival method was 65.2% at 48 months. When the IOP target was changed to ≤15 mmHg, the bleb survival rate was 47.8% at 48 months. At the most recent postoperative visit, 95.7% of eyes had an IOP of ≤15 mmHg and 56.5% were being treated with an average of one medication per eye. One eye (4.3%) required a second bleb revision for persistent hypotony and two eyes required glaucoma surgery to reduce IOP during follow-up. Conclusions: An algorithm approach for the surgical management of late-onset bleb complications with a success rate similar to those reported in specialized literature is proposed. Randomized trials are needed to confirm the best surgical approach.