[The effect of body position on the results of central and paracentral rebound tonometry]. / Vliyanie polozheniya tela na rezul'taty tochechnoi kontaktnoi tonometrii v tsentre i na periferii rogovitsy.

PURPOSE: This study analyzes the fluctuations of intraocular pressure (IOP) and clarifies the error of paracentral rebound tonometry associated with change in body position. MATERIAL AND METHODS: The study included 45 healthy volunteers aged 25.4±2.1 years. First we performed rebound tonometry in the sitting position in the center of the cornea and 3-4 mm from the temporal and nasal sides (Icare-c, Icare-n, Icare-t, respectively) and bidirectional applanation tonometry (IOPcc - corneal compensated, IOPg - Goldmann tonometry). Then we measured Icare-c, Icare-n, Icare-t in the supine position, and after 5 minutes repeated Icare-c in the supine position. After this, we measured Icare-c, IOPcc and IOPg in the sitting position. RESULTS AND DISCUSSION: Initial IOPcc and IOPg were 4.6±2.8 and 14.8±2.8 mm Hg. Initial Icare-c, Icare-t, and Icare-n measurements amounted to 15.0±1.9, 15.7±1.5 and 16.3±1.3 mm Hg; in the supine position the measurements were 16.4±2.1, 17.2±1.7 and 17.1±1.9 mm Hg. Paracentral measurements differed from Icare-c in both sitting and supine positions; only between Icare-t and Icare-n measured in the supine position there were no significant differences. The results of Icare-c, Icare-t, and Icare-n in body position change were comparable. Icare-c measured after 5 minutes in the supine position increased up to 16.6±2.4 mm Hg. Final IOPcc and IOPg did not differ from the initial measurements. Final Icare-c was lower than the initial result by 0.8±0.2 mm Hg, and lower than both supine Icare-c measurements by 2.1±0.2 and 2.6±0.2 mm Hg. CONCLUSION: Paracentral rebound tonometry findings exceed those of rebound tonometry in central cornea, but in body position change the alteration of measurements in the same points on the cornea are comparable. In the supine position IOP increases on average by 1.0-1.5 mm Hg compared to the sitting position.

[Intraocular pressure measurement inside the anterior chamber: a new technical solution and results]. / Izmerenie davleniya v perednei kamere glaza: novoe tekhnicheskoe reshenie i rezul'taty.

AIM: To develop a new manometric device for intravital measurement of intraocular pressure (IOP) in the anterior chamber and to assess tonometric data reliability, including post-radial keratotomy (RK) measurements. MATERIAL AND METHODS: The experiment was conducted in 2 isolated cadaver eyes, while the clinical study enrolled 20 patients (21 eyes) scheduled for cataract phacoemulsification surgery. Of them, 10 patients (10 eyes) with immature cataract and mild to moderate myopia constituted the control group. The study group consisted of the other 10 patients (11 eyes) with immature cataract, who had undergone RK more than 15 years earlier. The following tonometry methods were used: dynamic bi-directional corneal applanation (ORA, Reichert, USA), dynamic contour tonometry (Pascal tonometer, Zeimer, Switzerland), and rebound tonometry (ICare Pro, Tiolat, Finland). An original device was developed for intravital manometric measurements. RESULTS: Manometric data obtained during the experiment matched the preset pressure in the anterior eye chamber. The median manometry results in the control and study groups were similar and equaled 21.5 and 21.0 mmHg, respectively. Preoperative tonometry readings ranged from 14.9 to 16.5 mmHg in the control group and from 19.7 to 23.3 mmHg - in the study group (with the exception of midperipheral rebound tonometry that showed 15.8 mmHg). CONCLUSION: The developed device can well be used in experimental research. Midperipheral rebound tonometry was found to be the most informative method for post-RK IOP assessment. Manometry results in the study group mismatched tonometry readings in the controls, which might be due to the specifics of equipment calibration and requires further investigation.

[Modern methods of minimally invasive glaucoma surgery]. / Sovremennaia mikroinvazivnaia khirurgiia glaukom.

Over the years, glaucoma surgery has improved from iridectomy by A. Graefe and traumatizing procedures performed without magnification tools or microsurgical instrument to high-technology interventions that are not only microscopic, but also pathogenetically oriented. Various modifications of trabeculectomy, initially introduced by J. Cairns back in 1968, had been the gold standard for several decades and were notable for pronounced and stable hypotensive effects. However, there was also a strong association with such complications as choroidal detachment and hyphema, thus, boosting the development of so called nonfistulizing surgeries. Of the latter, the most widely used are non-penetrating procedures, including deep sclerectomy and viscocanalostomy. Although very safe, they appear unable to produce a truly long-lasting hypotensive effect. Moreover, just as fistulizing trabeculectomy, non-penetrating procedures damage the limbus and adjacent conjunctiva reducing the possibility of a second intervention. This fact together with other drawbacks mentioned above, on the one hand, and technical progress, on the other, were essential prerequisites for the appearance of a new type of surgery - minimally invasive glaucoma surgery (MIGS). Parameters that should be met for a procedure to be considered minimally invasive are debated. The main requirement has, however, been established: ab interno approach through a corneal incision. As surgical tools are enhanced and new techniques arise, options for glaucoma treatment widen greatly, ensuring our future move to higher level standards in the field. This review contains all recent data on minimally invasive techniques currently in use in glaucoma surgery or those under investigation. The authors have also analyzed effectiveness reports and present their conclusions regarding the current state of MIGS worldwide.

[Progressive hyperopic shift after radial keratotomy: possible causes].

AIM: To describe possible causes of progressive hyperopia in patients who underwent radial keratotomy. MATERIAL AND METHODS: The study enrolled 33 subjects who underwent radial keratotomy earlier in their lives, of them 15 controls (29 eyes, group 1) with no refractive error and 18 patients (35 eyes, group II) with progressive hyperopia. The number and type of keratotomy scars was determined during biomicroscopy. Biomechanical properties of the cornea were assessed by means of bidirectional applanation (Ocular Response Analyzer). Dynamic contour tonometry (Pascal) was also used for intraocular pressure (IOP) measurement. Evaluation of the optic nerve head and retina included standard automated perimetry (Humphrey Field Analyzer) and confocal scanning laser ophthalmoscopy with Heidelberg Retinal Tomograph (HRT III). RESULTS: Group II showed reliable signs of low corneal rigidity, namely reduction of CH and CRF values (by 2.4 and 1.6 mmHg respectively) and central corneal thickness (by 56 microns) as compared to the controls. Tonometry results differed inconsiderably showing a tendency toward hypertension in both groups. The interquartile range of IOP was 17.8 ÷ 22.4 mmHg in group II and 16.3 ÷ 20.6 mmHg in group I. Changes in retinal light sensitivity and optic nerve head parameters were more pronounced in the controls. CONCLUSION: Several reasons for lowering of corneal rigidity can be suggested: initial biomechanical parameters of the cornea, surgical interference, and age-related changes. We think that hyperopic shift results from the combination of low corneal rigidity and increased IOP, i.e. not the lamina cribrosa but the cornea becomes the target of ocular hypertension. Thus, patients with weakened corneal refraction after radial keratotomy are at risk for developing glaucoma in the late postoperative period.

[Options for prolonging the hypotensive effect of trabeculectomy].

OBJECTIVE: To assess potential of preoperative therapy with local steroid and non-steroid anti-inflammatory drugs (SAIDs and NSAIDs) for prolonging the hypotensive effect of trabeculectomy. MATERIAL AND METHODS: A total of 80 patients with primary open-angle glaucoma planed for trabeculectomy were randomized into 4 groups of 20 each: 3 groups that differed in the studied drug (nepafenac, dexamethasone, or their non-fixed combination) and a control group with no preoperative therapy. The patients instilled 1 drop of either drug b.i.d. for 2 weeks before the surgery and were examined each day of the first week and then at weeks 1, 2, 4 and months 3, 6, and 12. The rate of postoperative surgical and medical interventions (needling, needling revision, hypotensive therapy) was used for outcome evaluation. RESULTS: Postoperative needling was required in 50% of the controls, 35% of the NSAIDs and 30% of the SAIDs patients as well as 20% the combination-therapy patients. Needling revision had to be performed in 10% of patients from the control group and 5% of patients from the NSAIDs group. Patients from the steroid and combination-therapy groups had no need in needling procedure. Further hypotensive therapy was required in 50% of the control group, 35% of the NSAIDs group, 25% of the SAIDs group and 20% of the combination-therapy group. During the first postoperative year complete success of the treatment was achieved in 50% of the controls, 65% of the NSAIDs patients, 75% of the SAIDs patients, and 80% of those under combination therapy. Qualified success during the same period was achieved in 100% of cases. CONCLUSION: Preoperative local anti-inflammatory therapy helped to increase the one-year complete success rate after trabeculectomy as compared with the controls. The most significant hypotensive effect was noted in the combination-therapy group (80%), less significant--in the steroid and non-steroid monotherapy groups (75% and 65% correspondingly). A negative correlation was noted between the use of nepafenac and dexamethasone and other measures aimed at increasing the hypotensive effect of glaucoma surgery.