PubMed · 10365326
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
T Hoang-Xuan. 1999. [The ocular surface].. https://pubmed.ncbi.nlm.nih.gov/10365326/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
PURPOSE: To evaluate the effect of temporary punctal occlusion on tear production, tear clearance, and ocular surface sensation in normal subjects. METHODS: Noncomparative interventional case series. Punctal occlusion with silicone punctal plugs was performed on nine normal subjects without complaints of ocular irritation and no known history of ocular surface disease. The lower punctum of both eyes was occluded in five subjects. The upper and lower puncta of only one eye were occluded in four subjects. Corneal and conjunctival sensations were measured with the Cochet-Bonnet anesthesiometer. Tear fluorescein clearance was evaluated with a CytoFluor II fluorophotometer by measuring the fluorescein concentration in minimally stimulated tear samples collected from the inferior tear meniscus 15 minutes after instillation of fluorescein. Schirmer test was performed without anesthesia. The tests were performed at days 0, 1, 3, 7, and 14 to 17 after punctal occlusion. Relationships were analyzed with linear regressions, and a quadratic term was used to model a return to preocclusion levels. Paired t test was used to study the change in tear fluorescein concentration. RESULTS: In subjects who had the lower puncta of both eyes occluded, conjunctival sensation decreased in both eyes (right eye, P =.008; left eye, P =.003), but there was no change in corneal sensation. Their tear fluorescein clearance did not show a significant change from baseline (P =.90). However, a decrease in Schirmer test scores approached statistical significance (P =.056). In subjects with both puncta of only one eye occluded, we noted a decrease in corneal sensation (occluded eye, P =.042; nonoccluded eye, P =.036), conjunctival sensation (occluded, P =.001; nonoccluded, P =.060), and Schirmer scores (occluded, P =.022; nonoccluded, P =.011). Linear regression did not show a significant change in tear fluorescein clearance for either eye (occluded, P =.28; nonoccluded, P =.44). However, paired t test showed a significant worsening of tear clearance in the occluded eye from day 0 to day 3 (P =.001) followed by a subsequent improvement in tear clearance from day 3 to the end of the study period (P =.045). Paired t test did not reveal any significant changes in tear clearance in the nonoccluded eye. The quadratic term of the linear regression model demonstrated an increase toward preocclusion levels that approached statistical significance for corneal sensation (occluded, P =.053; nonoccluded, P =.099). It was statistically significant for conjunctival sensation (occluded, P =.001; nonoccluded, P =.045) and Schirmer scores (occluded, P =.047; nonoccluded, P =.044). CONCLUSIONS: Temporary punctal occlusion in normal subjects decreases tear production and ocular surface sensation. Our findings suggest that in addition to blocking tear drainage, punctal occlusion may affect the ocular surface/lacrimal gland interaction. These effects were more pronounced in subjects with both upper and lower puncta occluded. In normal subjects, there appears to be an autoregulatory mechanism to return tear production, tear clearance, and ocular surface sensation to preocclusion levels 14 to 17 days after punctal occlusion.
OBJECTIVE: The purpose of this document is to describe nonpenetrating glaucoma surgery and to examine the available evidence to assess the efficacy and complications following the procedures. METHODS: A literature search that was conducted in February 2000 and repeated in September 2000 for the years 1968 to 2000 retrieved over 100 citations that matched the search criteria. Thirty three articles were selected as relevant to the assessment, and they were each evaluated by the panel methodologist for the quality of the evidence presented. RESULTS: One randomized controlled trial comparing nonpenetrating deep sclerectomy to trabeculectomy has been reported. The majority of the published literature contains information from case series, which are not randomized and lack a control group. The two major variations of nonpenetrating glaucoma surgery described in the literature are nonpenetrating deep sclerectomy and viscocanalostomy. The procedures are not familiar to many ophthalmologists, and reports often describe a difficult learning period. These procedures appear to lower intraocular pressure, usually to the mid to high teens, although follow-up is limited in most published reports. Postoperative complications due to overfiltration and hypotony are uncommon in the literature. There is no strong evidence indicating the mechanism of action, reports on bleb formation are lacking, and clinical correlation and gonioscopic findings have been minimal. CONCLUSIONS: Nonpenetrating glaucoma surgery has the potential to reduce intraocular pressure while minimizing the risk of postoperative relative hypotony and the complications associated with hypotony. Randomized clinical trials are needed to assess these procedures and to determine their role in the clinical management of glaucoma patients.