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StartHealth ScienceRefractive astigmatism in phaco-canaloplasty vs phaco-non-penetrating deep sclerectomy

Refractive astigmatism in phaco-canaloplasty vs phaco-non-penetrating deep sclerectomy


This paper represents additional facets of a beforehand printed research, the place sufferers and strategies have been described intimately5,11. The strategies and outcomes are introduced in step with Pointers on Design & Reporting Glaucoma Trials12. This research is in step with European Union entitled Good Medical Follow for Trials on Medical Merchandise within the European Neighborhood and the tenets of the World Medical Affiliation Declaration of Helsinki. The venture obtained approval from the Institutional Evaluation Board of the Navy Institute of Drugs in Warsaw (9/WIM/2011) and was registered at NCT01726543 on 15/11/2012.

Sufferers with coexisting glaucoma and cataract (NC1 and NC2) labeled based on the Lens Opacificities Classification System LOCS III have been certified for the research. In all instances glaucoma process was carried out with cataract extraction and monofocal IOL implantation.

Glaucoma varieties

Varieties of glaucoma eligible for the research have been major open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PEX), and pigmentary glaucoma. Other than the kind of glaucoma, sufferers should have had at the least one of many following options: well-documented development of the visible discipline; non-compliance in anti-glaucoma remedy or allergy to topical drugs, each day fluctuations in strain. Each PC and PDS in addition to surgical alternate options have been defined intimately to candidates. After declaring willingness to take part within the research, every affected person signed an knowledgeable consent.


The design of the research was randomized and potential. Randomization into teams was carried out by a random sorting algorithm with an allocation ratio set to 1.0 on the day of surgical procedure.

A single doctor (AB) was liable for the preoperative examination, randomization, and postoperative care. Additionally, a single surgeon (MR) carried out all of the surgical procedures after which was excluded from any additional medical involvement on this research to keep away from bias.

In the midst of the research the intraocular strain (IOP), the variety of antiglaucoma drugs, Finest Corrected Visible Acuity (BCVA), autokeratorefractometry (AKR), Humphrey 24-2 visible fields (VF), Optical Coherent Tomography (OCT) morphology of the surgical web site, High quality of life (QoL) assessment- have been collected prospectively5,11.

Preoperative examination

On the baseline go to, ophthalmic and basic medical historical past was taken. Throughout the go to the AKR measurement was carried out as the primary examination, to keep away from any affect from different, particularly contact examinations. Then uncorrected distance visible acuity and BCVA have been checked, adopted by parameters required for IOL calculation equivalent to axial size and keratometry. Central corneal thickness was additionally evaluated. We collected information of IOP with the variety of antiglaucoma drugs taken. Routinely a gonioscopy was carried out. All topics had a dilated slit-lamp examination.

IOP measurements

The IOP was measured with a Goldmann applanation tonometer and all measurements included within the evaluation have been taken between 8 and 10 am. Throughout the qualification go to, a diurnal curve of IOP was assessed and a single measurement on the day of surgical procedure was taken. Routinely, two measurements have been taken, in the event that they different greater than 1 mmHg, the third one was taken, and the result was the common of the three measurements. Primarily based on IOP values, the course of imply IOP was outlined.


A typical ETDRS chart was used to measure the BCVA. The calculations have been carried out utilizing logMAR -a logarithm of the minimal angle of decision. SRK T system was used to calculate the IOL.

Surgical process

Surgical procedures have been beforehand described intimately5,11. For a greater understanding of the outcomes, the outline is cited under. All surgical procedures have been carried out beneath retrobulbar anesthesia (2% xylocaine and 0.5% bupivacaine) by one skilled surgeon (MR). Traditional canaloplasty was carried out with a normal canaloplasty set (iTrack from Ellex Medical Lasers Pty Ltd., Adelaide, Australia). Nonpenetrating deep sclerectomy was carried out with a Healaflow implant, a slowly resorbable crosslinked viscoelastic gel (Anteis Ophthalmology, Geneva, Switzerland). In each procedures, a fornix-based superficial scleral flap was dissected, adopted by a deep scleral flap and a TDM dissection. Throughout the subsequent step, a 2.2 mm clear corneal temporal incision was made, the cataract was phacoemulsified (Infiniti Imaginative and prescient System, Alcon Surgical, Fort Value, TX), and a monofocal IOL was implanted. The deep scleral flap was excised. In PC, 360° of the Schlemm’s canal circumference was catheterized and viscodilated with 10.0 Prolene suture left beneath rigidity to distend the trabecular meshwork inward. In PDS, after dissection of TDM, the roof of Schlemm’s canal was eliminated. The superficial scleral flap was then loosely sutured to the sclera, and HealaFlow was injected beneath the flap to create a filtering bleb. In PC, the superficial flap was sutured tightly to stop leakage and subsequent bleb formation with interrupted 10-0 monofilament nylon suture. The conjunctiva was sutured down over the limbus with one interrupted 8.0 Vicryl suture.

Postoperative protocol

The postoperative visits have been scheduled for days 1 and seven and 1, 3, 6, 12, 18, and 24 months after surgical procedure. Nevertheless, sufferers have been knowledgeable that they’ll present up any time when wanted. A topical steroid and antibiotic mixture was prescribed for 4 weeks after surgical procedure. Throughout postoperative examinations, AKR information was collected as the primary one, adopted by BCVA evaluation after which IOP was decided and the variety of hypotensive drugs was famous. Afterwards the anterior section examination together with gonioscopy (within the case of PC, to evaluate any attainable issues) and on the finish of go to a dilated pupil fundoscopy was carried out. Glaucoma medication have been discontinued on the day of surgical procedure. In the midst of the research, drugs have been administered once more, when required, beneath the rules of the European Glaucoma Society. Problems that occurred inside 30 days have been analyzed as early, whereas after 30 days have been thought-about as late. To maintain IOP at a sufficiently low degree, further procedures have been carried out. Within the case of PDS, they have been related to filtering bleb upkeep equivalent to 5-FU subconjunctival injections (when indicators of bleb failure have been seen—new, tortuous vessels, hyperemia, or encapsulation), suture lysis, and needling. 5-FluoroUracil was injected in a dose of 0.2 ml (5 mg) within the decrease fornix of the operated eye. If needling of filtering bleb was required (encapsulated and flat blebs, which brought on elevated IOP), the affected person was anesthetized with proxymetacaine eye drop, and needling was carried out on the slit lamp, adopted by 5-FU injection. Goniopuncture, which is laser puncture of TDM, was carried out in each PC and PDS, when filtration by way of TDM was suspected to be inadequate (with an Nd: YAG laser, about 3–20 photographs have been utilized utilizing power starting from 2 to 4 mJ).

Refractive parameters

The refraction was recorded on the central 3-mm diameter by Auto-kerato-refractometry (Topcon TRK 2P), which is serviced based on producer suggestions. The AKR information was analysed on the baseline, then 6 months and 24 months post-surgery. All calculations have been carried out after the transposition of the cylinder values to the plus type.

Two varieties of evaluation have been performed- refractive and vector.


The primary one is the straightforward arithmetic calculation of the imply of the cylinder, with out contemplating its axis. This evaluation was carried out to debate the numerical outcomes obtainable within the literature. Such a distinction within the imply worth of the cylinder permits reporting the imply change within the magnitude of astigmatism. Mixture information of astigmatism values are depicted within the cumulative information plots.


The vector evaluation—the second technique introduced is a calculation of the cylinder change with consideration of its axis, which leads to a calculation of centroid. The preoperative and postoperative refractive measurements (cylinder with its axis) have been evaluated by vector evaluation, based on the strategy proposed by Holladay et al13 Centroid is a type of astigmatism, which is calculated in a sure means (see under), in order that it may be introduced as a set of x and y values on a cartesian graph (normal polar information are transformed to cartesian values appropriate for calculations, however nonetheless together with the axis). What’s most vital centroid incorporates the magnitude and axis of astigmatism. It may be then included in the usual descriptive statistics (means, normal deviations). When a bigger set of information is introduced, centroid means the imply of all values, and a pattern for astigmatism could be described (with the rule, in opposition to the rule, or indirect).

The information have been transformed from normal polar values (cylinder and axis) to Cartesian values (level with x,y coordinates) to judge developments in astigmatism (in opposition to the rule, with the rule or indirect) and to outline imply astigmatism in centroid type.

For conversion from polar to cartesian values the next mathematical system was utilized:

$$start{gathered} {textual content{x}} = {textual content{cyl}}*{textual content{cos}}left( {{2}*{textual content{axis}}} proper) hfill {textual content{y}} = {textual content{cyl}}*{textual content{sin}}left( {{textual content{2axis}}} proper) hfill finish{gathered}$$

Then the Cartesian coordinates have been transformed to straightforward polar values, with formulation:

$$start{gathered} {textual content{cyl}} = surd left( {{textual content{x2}} + {textual content{y2}}} proper){textual content{Angle}} = {1}/{2 }*({textual content{ tan}} – {1 }left( {{textual content{ y }}/{textual content{ x }}} proper) hfill {textual content{if x}} > 0{textual content{ and x}} > 0{textual content{ angle }} = {textual content{ axis}} hfill {textual content{if x}} < 0 {textual content{ axis}} = {textual content{angle }} + {9}0^circ hfill {textual content{if x}} > 0{textual content{ and y}} < 0{textual content{ axis}} = {textual content{angle }} + { 18}0^circ hfill {textual content{if x}} = 0 {textual content{ a y}} < 0{textual content{ axis}} = {135}^circ hfill {textual content{if x}} = 0 {textual content{ a y}} > 0{textual content{ axis}} = {45}^circ hfill {textual content{if x}} = 0{textual content{ i y}} = 0{textual content{ axis}} = 0^circ hfill {textual content{if y}} = 0{textual content{ a x}} < 0{textual content{ axis}} = {9}0^circ hfill {textual content{if y}} = 0{textual content{ a x}} > 0{textual content{ axis}} = 0^circ hfill finish{gathered}$$

The calculation was carried out for every particular person, to compute particular person surgically induced refractive change. The imply of all x and y allowed to calculate mixture refractive change for the analyzed teams.

The information was displayed within the double angle plots (the angles needed to be doubled because the astigmatism vector returns to the identical worth when it traverses an angle of 180 levels).

The key and minor axes of the ellipse surrounding the centroid have been decided by normal deviations of x and y coordinates. The pattern of astigmatism was evaluated relying on centroid values and axis.

The double-angle plots have been depicted with the assistance of a double-angle plot instrument for astigmatism obtainable on the ASCRS web site14.

Statistical analyses

The Shapiro–Wilk was used for the evaluation of the normality of the information. Non-parametric information have been calculated with a χ2 take a look at with corrections. Comparisons between the teams (IOP, BCVA, refractive astigmatism) have been carried out with U Mann–Whitney take a look at, and the Scholar’s T-test. Friedman’s evaluation of variance (ANOVA) for matched teams, imply ranks, and rank sums have been additionally used for posthoc comparisons. A P-value of 0.05 or much less was thought-about vital. Calculations have been carried out utilizing the Statistica 10.0 PL software program.


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