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Biomedical subjects

M Gonvers

Publications and source records attributed to M Gonvers.

At least 19 recordsLinked to original sources
PubMed1998

Change in capsulorhexis size with four foldable loop-haptic lenses over 6 months.

PURPOSE: To compare the change in continuous curvilinear capsulorhexis (CCC) size after implantation of four types of three-piece foldable intraocular lenses (IOLs) and determine whether initial CCC size and IOL characteristics play a role in the change. METHODS: This study comprised 133 eyes that had phacoemulsification and in-the-bag implantation of one of four types of foldable IOLs: Alcon AcrySof MA30BA (n = 36); lovision 127 (n = 29); Mentor ORC MemoryLens (n = 39); Allergan PhacoFlex II (n = 29). Photographs of the CCCs were taken with a digital retinograph 1 day and 6 months after surgery. Using image-analysis software, the CCC surface was measured and changes between 1 week and 6 months were evaluated. Characteristics of the IOLs including overall diameter, optic thickness, and haptic centrifugal force were measured with micrometric tools. RESULTS: The median change in CCC surface size at 6 months was +5.5% in the lovision group, indicating a slight enlargement. This finding was significantly different from that in the other three IOL groups (P < .0001), which had a tendency toward CCC contraction. Median change in CCC size was -2.3% in the MemoryLens group, -2.8% in the AcrySof group, and -6% in the PhacoFlex group. The MemoryLens was the most predictive IOL, with the smallest standard deviation; it was the only group in which no patient developed CCC contraction of more than 10%. Although the lovision and PhacoFlex IOLs have common physical characteristics except for optic thickness (lovision 30% thicker), the CCCs in the lovision group were significantly more stable (P < .0001). Results indicate that the high centrifugal haptic force associated with acrylate/methacrylate polymer optics of the AcrySof and MemoryLens IOLs may prevent CCC contraction of greater than 10% in 97.4% of cases. CONCLUSION: Although there were statistically significant differences, patients in all four three-piece foldable IOL groups had good CCC stability. However, the more stable and predictable CCCs were in the IOL groups that had the strongest centrifugal haptic force and an acrylate/methacrylate polymer optic (AcrySof and MemoryLens).

Acrylic Resins↗
PubMed1998

[Surgical treatment of retinal detachment in pseudophakia: comparison between vitrectomy and scleral buckling].

OBJECTIVE: For the primary treatment of pseudophakic retinal detachment, vitrectomy could be preferred to episcleral buckle because it does not induce myopia, it clears opacities of the posterior capsule and/or of the vitreous and allows a good visualization of the fundus. This study was determined to compare the anatomic and functional results of vitrectomy and episcleral buckle. METHODS: from 1990 to 1995, 93 pseudophakic eyes were operated on for retinal detachment. 75 eyes were treated with episcleral buckle (group I) and 18 eyes were treated with vitrectomy (group II). In the latter group, 4 eyes had a giant tear, and 4 other eyes had a macular hole associated with high myopia. The anatomic and functional results were analyzed retrospectively. RESULTS: The retina was reattached with one operation in 67 eyes of group I (89%) and 16 of group II (89%). More than one month after the first operation, the retina redetached in 6 eyes of Group I (8%) and one eye of group II (6%). The causes of failure were a) new or missed retinal tears [Group I: 10 eyes (13%), group II: 3 eyes (17%)] and b) vitreoretinal proliferation (group I: 4 eyes, group II: 0). The number of subsequent reoperations for failures or recurrences was higher in group I than in group II. At the final examination, the retina was attached in 73 eyes of group I (97%) and in 18 eyes of group II (100%). The Kruskal-Wallis test did not detect any difference between the two groups concerning the pre- or postoperative visual acuities. CONCLUSION: Vitrectomy seems as effective as episcleral buckle for the treatment of pseudophakic retinal detachment and offers additional advantages.

Adolescent↗
PubMed1998

[Surgery of sub-foveal neovascular membranes].

BACKGROUND: To present the functional, angiographic and electron microscopic results of 3 patients who underwent surgical removal of a subfoveolar neovascularisation. These patients are representative of the most common indications for subfoveolar surgery. MATERIAL AND METHOD: In one case, the neovascularization originated from an old chorioretinal scar close to the macula; in another case, it was associated with high myopia; in the last case the neovascularization was coupled with an age-related macular degeneration (ARMD). The 3 removal neovascular membranes were examined by electron microscopy. Indocyanine green and fluorescein angiographies were performed in all 3 cases before and after surgery. RESULTS: Visual recovery was excellent in the case of neovasularization and old chorioretinitis scar; it was minimal in the case of high myopia; no objective improvement was found in the case of ARMD. Electron microscopic examination did not always allow to determine accurately if the neovascularization was located in the subretinal space or under the pigment epthelium. CONCLUSIONS: These results match those already published: surgical prognosis is the best when neovascularization is in the subretinal space and when the pigment epithelium has not been damaged by the underlying disease or by the surgical maneuvers. Electron microscopic examination is not easy to interpret.

Aged↗
PubMed1997

Change in capsulorhexis size after implantation of three types of intraocular lenses.

PURPOSE: To compare the change in size of continuous curvilinear capsulorhexis (CCC) used for implantation of three types of intraocular lenses (IOLs) and to determine the role of postoperative inflammation, initial CCC dimension, haptic design, and optic material. SETTING: Hôpital Ophtalmique Universitaire Jules Gonin, Lausanne, Switzerland. METHOD: Twenty-nine three-piece, silicone/poly(methyl methacrylate) (PMMA) IOLs (lovision 127), 26 one-piece PMMA IOLs (Pharmacia 812A), and 27 plate-haptic silicone IOLs (Staar AA4203) were implanted in the capsular bag after phacoemulsification. Photographs of the CCCs taken 1 day and 6 months after surgery were scanned and digitized on a computer. Using different software, the surface of the CCC was measured and the 6 month change evaluated. Flare, measured the day before surgery and postoperatively at days 1, 7, 30, and 180, was integrated to obtain a global estimate of inflammation during the 180 day follow-up. RESULTS: The CCCs used with three-piece, silicone/PMMA IOLs showed little changes in surface, with a mean enlargement of +0.57 mm2 +/- 1.15 (SD) (+3.5%). The CCCs used with the one-piece PMMA IOLs had a slight tendency to constrict, with a mean surface decrease of -0.59 +/- 2.16 mm2 (-4.3%). The CCCs used with plate-haptic silicone IOLs showed a marked and statistically significant constriction, with a mean decrease of -2.55 +/- 3.51 mm2 (-14.4%). The change in CCC size was not associated with the integrated flare, and no correlation was found between the initial CCC size and the magnitude of change. There was no statistically significant difference in CCC change between the PMMA optic IOL (Pharmacia) and silicone optic IOL (lovision and Staar) groups. The CCC in the plate-haptic IOL (Staar) group showed a significant (P < .0002) constriction when compared with that in the loop-haptic IOL (Pharmacia and lovision) group. CONCLUSION: The IOLs' haptic design seemed to play a major role in the evolution of the CCC. The CCC constriction seen with the Staar IOLs was related to their plate haptics.

Aged↗
PubMed1996

[Phacoemulsification and clear cornea incision: review of 100 initial cases].

AIM: Evaluation of complications during the learning period of phacoemulsifications with clear-corneal incision. PATIENTS AND METHODS: Retrospective study of the 100 first cases with a follow-up of 3 to 24 months. RESULTS: During operation, 5 (5%) cases (one 180 degrees dialysis, 4 broken posterior capsules) presented with a significant complication needing anterior vitrectomy. Eight corneal tunnels were sutured at the end of surgery and 3 others a few days later. No case showed signs of intraocular infection. Cystoid macular edema developed in 4 patients who all recovered good visual acuity. Excessive fibrosis of anterior capsule with capsulorhexis contraction was encountered in 2 cases harbouring plate haptic silicone lenses and needed YAG-laser treatment. None of the eyes with complications had visual acuity inferior to 0.6, except for 2 eyes which had preoperative macular diseases. CONCLUSION: This study demonstrates that phacoemulsification with clear cornea incision is a safe procedure, provided that the complications related to the learning period are set apart. None of the complications encountered in our 100 first cases severely prejudiced the functional results.

Adult↗
PubMed1996

[Laser treatment of macular holes].

OBJECTIVE: To study a new technic of laser treatment of macular holes. METHODS: 21 eyes with stage II-IV macular hole were treated with Argon-green laser. Pigment epithelium in the area of the hole was whitened with spots of 100-200 microns, 100-300 mW. We expected this treatment to create a cellular proliferation that could close and contract the hole. Follow-up after treatment ranged from 3 to 24 months (mean: 9.3 months). RESULTS: Within one month after treatment, the macular hole was closed in 7 eyes (33%) and partially closed in 5 eyes (24%). The visual acuity increased from 1 to 5 lignes (ETDRS chart) in 9 eyes (43%), it remained the same in 9 eyes (43%) and decreased from 1 to 2 lignes in 3 eyes (14%). CONCLUSION: Laser treatment of macular holes seems to be effective and could be proposed as an alternative to the patients who cannot be operated on by vitrectomy and gas tamponade.

Adult↗
PubMed1995

A new device for noncontact wide-angle viewing of the fundus during vitrectomy.

Noncontact wide-angle viewing of the fundus during vitrectomy has heretofore relied on an image inverter and a 90-diopter lens fixed with a tube under the microscope. A new device in which the 90-diopter lens is not connected to the microscope but, rather, is connected to an independent support system is described. This device offers many advantages: (1) focusing on the various parts of the eye during vitreous surgery need not be done manually but is achieved by the up or down movement of the microscope, (2) translation of the microscope is easier during tilting of the eye, (3) a lateral slit-lamp can be easily added for illumination of the fundus, and (4) there is no risk that the 90-diopter lens will touch the cornea.

Equipment Design↗
PubMed1995

[Silicone one piece intraocular implant and anterior capsule fibrosis].

BACKGROUND: Foldable plate haptic silicone intraocular lenses (IOLs) were surmised to produce greater anterior capsule fibrosis than poly(methyl metacrylate) (PMMA) intraocular lenses. MATERIAL AND METHODS: A retrospective study of 34 eyes was carried out 12 to 15 months after phacoemulsification. All surgical procedures were performed by the same surgeon (M.G.) using two different techniques: 17 eyes were operated on through a temporal clear-cornea incison and implanted with a foldable plate haptic silicone IOL (STAAR AA4203); 17 eyes were operated on through a superior sclerocorneal incision and received a PMMA IOL (Kabi Pharmacia 809P). Secondary opacification of the anterior capsule was compared between the two groups. RESULTS: Seventy percent of eyes (12/17) with plate haptic silicone IOL had moderate or important anterior capsule fibrosis or shrinkage. Only 18% of eyes (3/17) with PMMA IOL presented with this complication. However, posterior capsule opacification was almost similar in both groups. CONCLUSION: Foldable plate haptic silicone IOLs seem to produce a more important anterior capsule fibrosis or shrinkage than PMMA IOL one year after phacoemulsification and saccular implantation. Although etiology is unknown, either huge contact between IOL and anterior capsule, or lack of contact between anterior and posterior capsules are hypotheses advanced. Posterior capsule opacification is similar in the two groups.

Fibrosis↗
PubMed1995

[Retinal detachment and laser drainage].

OBJECTIVE: To compare laser and 30G needle perforation of the choroid for drainage of subretinal fluid. METHOD: Hundred and six cases of retinal detachment were operated on by episcleral buckle, retinopexy and external drainage of subretinal fluid. After radial sclerotomy, the choroid was perforated in 53 cases with Argon laser (group I) and in 53 other cases with 30G needle (group II). Complications were compared between both groups. RESULTS: Group I (laser drainage): In one of 53 eyes (1.8%), a retinal perforation occurred. In this eye, the retinal detachment was shallow. In an other eye (1.8%), retinal perforation occurred secondary to incarceration of the retina at the drainage site. Two eyes (3.6%) had limited hemorrhage at the drainage site. Group II (30G needle drainage): Three of 53 eyes (3.6%) had direct retinal perforation, and three (3.6%) had perforation secondary to retinal incarceration at the drainage site. Seven eyes (13.2%) had subretinal hemorrhage. CONCLUSION: Laser is safer than 30G needle for perforation of the choroid and drainage of subretinal fluid, and is associated with a lower incidence of retinal perforations and subretinal hemorrhages.

Adolescent↗
PubMed1995

Retinotomies of 180 degrees or more.

PURPOSE: To investigate the anatomic and functional results of large retinotomies. METHODS: The charts of 33 consecutive patients who underwent peripheral retinotomy of 180 degrees or more and silicone oil injection during vitrectomy for retinal detachment with proliferative vitreoretinopathy were reviewed. Silicone oil was removed from 26 eyes (79%), but 2 hypotonic eyes (6%) required reinjection of silicone. RESULTS: After a minimum follow-up of 6 months, the retina was completely attached in 28 eyes (85%). Twenty-eight eyes (85%) achieved a final visual acuity of 5/200 or better, and seventeen eyes (51%) achieved visual acuity of 20/200 or better. Intraocular pressure did not change significantly from the initial to the final examination. At the last follow-up, hypotony (intraocular pressure < or = 5 mmHg) was seen in 1 of the 28 eyes with reattached retina (3.6%). A new macular epiretinal membrane, related to the duration of silicone oil tamponade, developed and was peeled off in 12 eyes (36%) in an additional procedure. No association could be found between the anatomic or functional results and the extent of the retinotomy. Presented herein is the largest series of retinotomies of 180 degrees or more followed up after silicone oil removal. CONCLUSION: Large retinotomy (> or = 180 degrees) in selected cases of vitreoretinal surgery seems to be an effective procedure.

Adolescent↗
PubMed1994

New approach to managing vitreous loss and dislocated lens fragments during phacoemulsification.

I performed a one-port pars plana vitrectomy during phacoemulsification to manage vitreous loss with and without posterior dislocation of lens fragments in nine consecutive cases. I used a 1 mm vitrectomy instrument with an infusion sleeve for the vitrectomy; the coaxial light of the microscope and an infusion contact lens held on the cornea provided intraocular illumination. Eight of the nine cases achieved a visual acuity equal to or better than 20/25 after a mean follow-up of 5.7 months. One patient's visual acuity was 20/70 because of severe background diabetic retinopathy.

Cataract Extraction↗
PubMed1994

[Phacoemulsification with incision of the clear cornea].

METHODS: I reviewed the records of my first 33 phacoemulsifications with a clear cornea incision. The first 3 cases in the series had their temporal corneal incision sutured because of insufficiency in the self-sealing mechanism. RESULTS: Change of refraction induced by surgery was especially studied in 23 cases whose mean follow-up had been 3.5 months. This proved to be very moderate and stable from the first post-operative day up to the last control which took place 5-6 months later. CONCLUSION: The only drawback of the technique, was the occurrence in several cases of anterior capsule fibrosis which seemed related to the nature (silicone) and shape (plate haptics) of the foldable IOL.

Cataract Extraction↗
PubMed1993

Sophisticated vitreoretinal surgery in patients with a healthy fellow eye. An 11-year retrospective study.

Forty-four patients who had undergone successful vitreoretinal surgery were included in a retrospective study intended to evaluate the real benefit of surgery in each case. All patients presented with a retinal detachment complicated by proliferative vitreoretinopathy in one eye, the fellow eye being healthy. The number of operations undergone by each patient and the total operating time per patient were carefully recorded. Objective parameters such as visual acuity, visual field and stereoscopic function were monitored. Visual comfort and subjective complaints were graded by means of a questionnaire given to the patients. Any severe event occurring in the fellow eye during the follow-up period was also registered. Sophisticated vitreoretinal surgery in patients with a good fellow eye is useful to the patient if binocular function can be restored at least partially. Correction of unilateral aphakia by a contact lens should not be considered an acceptable solution.

Depth Perception↗
PubMed1992

[Pars plana vitrectomy in uveitis].

A vitrectomy was performed in 30 eyes suffering from different forms of uveitis. An improvement of visual acuity was obtained in 29 cases and was explained by removal of vitreous haze and/or of the cataract, but not by the improvement of the inflammatory process.

Adolescent↗
PubMed1992

[Ocular toxocara canis in a 30-year-old adult].

Pars plana vitrectomy was performed in a 30-year-old patient who presented a posterior traction detachment due to an inflammatory granuloma. The granuloma removed in toto during surgery revealed characteristic features of toxocariasis lesion (first case described in the literature). An ELISA test performed on a vitreous sample was strongly positive. Retinotomy around the granuloma was necessary to re-attach the retina and silicone oil was used as a tamponade for 4 months. VA improved from HM to 15/200 after silicone removal.

Adult↗