Algorithm approach for revision surgery following late-onset bleb complications after trabeculectomy: long-term follow-up / Algoritmo de abordagem para cirurgia de revisão nas complicações da bolha de início tardio após trabeculectomia: acompanhamento de longo prazo

ABSTRACT 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.

RESUMO Objetivo: Descrever um algoritmo reprodutível para o tratamento cirúrgico das complicações da bolha de início tardio (>2 meses) após trabeculectomia com mitomicina-C. Métodos: Revisão retrospectiva de olhos que foram submetidos a um algoritmo reprodutível para o tratamento cirúrgico das complicações da bolha de início tardio por um único cirurgião, de julho de 2006 a abril de 2014. Os critérios de exclusão foram revisão de bolha com menos de 3 meses de seguimento ou revisão de bolha combinado com outro procedimento antiglaucomatoso no momento da cirurgia. O sucesso foi avaliado pelo método de sobrevida de Kaplan-Meier e definidos como ter atingido todos os seguintes critérios: indicação de cirurgia primária resolvido, nenhuma cirurgia adicional necessária para diminuir a pressão intraocular (IOP), IOP ≥6 mmHg e ≤18 mmHg. Resultados: Vinte e três olhos de 20 pacientes foram incluídos. Indicações para revisão bolha foram maculopatia hipotônica (47,8%), extravasamento da bolha (30,4%) e bolha elevada (21,7%). A taxa de sucesso do resultado primário global calculada pelo método de sobrevivência de Kaplan-Meier foi de 65,2% aos 48 meses. Quando a IOP foi diminuída para ≤15mmHg, a taxa de sobrevivência bolha foi de 47,8% em 48 meses. Na visita pós-operatória mais recente, 95,7% dos olhos apresentavam PIO ≤15mmHg e 56,5% estavam sob tratamento com uma média de um medicamento por olho. Um olho (4,3%) necessitou de uma segunda revisão da bolha para hipotonia persistente e dois olhos necessitaram cirurgia de antiglaucomatosa para reduzir a IOP durante o seguimento. Conclusões: Um algoritmo de abordagem para o tratamento cirúrgico das complicações tardias da bolha com uma taxa de sucesso semelhante aos relatados na literatura especializada é proposto. Ensaios clínicos randomizados são necessários para confirmar a melhor abordagem cirúrgica.

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

BACKGROUND: Tear 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. RESULTS: Fern-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. CONCLUSIONS: Imaging 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.

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

BACKGROUND: Fern-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. RESULTS: In 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. CONCLUSION: Morphological characteristics of tear microdesiccates can provide insights into the relative rate of tear evaporation.

Microdesiccates produced from normal human tears display four distinctive morphological components

Desiccation of human tears on glass surfaces results in fern-like crystalloids. This phenomenon has been associated with tear normality (Tear Ferning Test, TFT) and is used as a diagnostic aid to evaluate patients with Dry-Eye disease. However, TFT is focused on the assessment of only a minor fraction of desiccated tear samples and considers only the relative abundance and density of fern-like crystalloids. The aim of this study was to characterize morphologically entire desiccated micro volumes of tears from healthy donors. Tear samples were collected from 23 healthy young adult volunteers. Tear aliquots (1-3 μL) were allowed to dry on glass surfaces under ambient conditions of temperature (15-25°C) and relative humidity (40-45%). Dry samples were analyzed by dark-field microscopy. Morphometric data were acquired with Image J software. Tear volume was positively correlated with both area and time of desiccation. Morphological features of multiple microdesiccates produced from a single subject displayed striking similarities whereas tear microdesiccates from different healthy subjects displayed consistent differences but shared a common general design. This design may be mostly represented by the occurrence of four distinctive zones, named as zones I, II, III and Transition band. The main features of these zones are described.