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Biomedical subjects

M G Lynch

Publications and source records attributed to M G Lynch.

At least 19 recordsLinked to original sources
PubMed2000

Long-term surgical and visual outcomes in primary congenital glaucoma: 360 degrees trabeculotomy versus goniotomy.

PURPOSE: To compare the visual outcome and refractive status of children with primary congenital glaucoma who underwent 360 degrees trabeculotomy or goniotomy as an initial surgical procedure. METHODS: This retrospective study describes 24 eyes (15 patients) with primary congenital glaucoma that underwent 360 degrees trabeculotomy as the initial procedure and 40 eyes (23 patients) that underwent goniotomy as the initial procedure. Inclusion criteria were: (1) diagnosis of primary congenital glaucoma and initial angle surgery before 1 year of age, (2) no other ocular or systemic diseases, (3) 360 degrees trabeculotomy or goniotomy as the first surgical procedure, and (4) ability to obtain an Allen or Snellen visual acuity. A postoperative vision of 20/50 or better was considered good. Surgical success was defined as an intraocular pressure (IOP) less than 22 mm Hg with or without medication and without evidence of a progressive optic neuropathy. RESULTS: The IOP was successfully controlled in 92% of eyes in the trabeculotomy group and in 58% of eyes in the goniotomy group (P =.004). Of eyes in the trabeculotomy group, 79% had vision of 20/50 or better compared with 53% in the goniotomy group (P =.03). High myopia was more prevalent in the goniotomy group, but this difference was not statistically significant (P =.16). A poor visual outcome was associated with failure of the angle surgery or poor compliance with follow-up and amblyopia therapy. CONCLUSION: For primary congenital glaucoma, 360 degrees trabeculotomy is a highly effective procedure that results in excellent pressure control and is at least as successful as multiple standard procedures. In this study, 360 degrees trabeculotomy resulted in better vision than what is reported in the literature for standard angle procedures.

Anterior Chamber↗
PubMed1998

Trabeculectomy with adjunctive mitomycin C in pediatric glaucoma.

PURPOSE: To determine the safety and efficacy of trabeculectomy with adjunctive mitomycin C in patients 17 years of age or younger, and to identify risk factors for failure of this surgical technique. METHODS: Retrospective review of consecutive cases of pediatric glaucoma that underwent mitomycin C augmented trabeculectomy between January 1991 and December 1995. Forty-nine patients (60 eyes) with a mean age of 7.6 years (range, 6 weeks to 17.6 years) were identified and followed up until repeat glaucoma surgery, or after a minimum of 6 months. Success was defined as intraocular pressure control of 22 mm Hg or less with or without topical glaucoma control medication, no evidence of glaucoma progression, no further glaucoma surgery necessary, and no visually devastating complication. RESULTS: Cumulative probabilities of success +/- SD for 49 eyes (one eye per patient) were 67% +/- 13% at 12 months and 59% +/- 15% at 24 months. Multivariate regression analysis yielded the following characteristics as significantly increased risk for failure: age of less than 1 year at time of surgery (risk ratio, 5.6; confidence interval, 2.1 to 14.7; P = .0005), and aphakia (risk ratio, 2.7; confidence interval, 1.1 to 6.9; P = .0364). Shallow anterior chamber (17 [28%] of 60 eyes) and serous choroidal detachment (13 [22%] of 60 eyes) were the most common complications. Four (11%) of 38 eyes with obtainable Snellen acuity were noted to have a decrease in best-corrected visual acuity of more than 2 Snellen lines or loss of light perception. In 5 (8%) of 60 eyes bleb-related endophthalmitis was noted. CONCLUSIONS: Trabeculectomy with adjunctive mitomycin C is generally effective for the treatment of pediatric glaucoma, especially in phakic children over 1 year of age. However, late-onset bleb-related endophthalmitis is a substantial risk in this patient population.

Adolescent↗
PubMed1996

Remodeling filtering blebs with the neodymium:YAG laser.

PURPOSE: To describe a new method of treating large, overfiltering, leaking blebs using a continuous-wave neodymium:YAG laser. METHODS: Twenty-three eyes of 23 patients underwent YAG laser remodeling because of overfiltration and hypotony (group 1; n = 14); leaking bleb and hypotony (group 2; n = 5); and large, irritating bleb (group 3; n = 4). Using a neodymium:YAG laser in the continuous-wave multimode, a grid pattern of laser treatment was placed over the entire bleb using energy levels between 3.0 and 4.0 J and a laser offset between 0.9 and 1.2 mm. A torpedo patch then was placed directly over the bleb for 48 hours. Steroid therapy was avoided. RESULTS: In group 1, 64% of eyes had an intraocular pressure increase of at least 3.0 mmHg. In group 2, 80% of bleb leaks were sealed. In group 3, 100% of patients had resolution of their discomfort. The elevation in intraocular pressure peaked at 1 to 3 months and diminished thereafter. There was improvement in vision of at least two Snellen acuity lines in 52% of eyes. Complications included the need for laser retreatment (7 eyes), creation of temporary bleb leak by the YAG laser (2 eyes), transient increase in intraocular pressure (2 eyes), and corneal edema (1 eye). CONCLUSION: The continuous-wave neodymium:YAG laser can be used to effectively change the appearance and behavior of filtering blebs, although the duration of treatment effect is unknown.

Adult↗
PubMed1995

360 degrees trabeculotomy for primary congenital glaucoma.

We have refined a technique for performing 360 degrees trabeculotomy in a single procedure using a 6-0 polypropylene (Prolene) suture fragment and have used it in 15 patients (26 eyes) with primary congenital glaucoma. The refined technique can be performed via a single nasal surgical site. This procedure avoids many of the difficulties encountered with metal trabeculotomes and preserves conjunctiva should further glaucoma surgery be necessary.

Child↗
PubMed1995

Neodymium: YAG membranectomy for pupillary membranes on posterior chamber intraocular lenses.

PURPOSE: To evaluate the effectiveness of neodymium: YAG laser for the removal of membranes from the anterior surface of intraocular lenses. METHODS: Seven patients had reduced vision due to a membrane on the anterior surface of a posterior chamber intraocular lens (PC IOL). Six of the membranes developed after extracapsular cataract surgery and PC IOL combined with trabeculectomy and one after pars plana vitrectomy. Six of the membranes developed in the early postoperative period in association with a fibrinous reaction of the anterior chamber. One formed 7 months after surgery in an eye with iris capture behind the IOL. The membranes persisted despite intensive topical steroid therapy. A neodymium: YAG (Nd:YAG) laser was used to remove the membranes from the anterior of the IOL in all the seven cases. RESULTS: The Nd:YAG laser effectively severed the peripheral connections of the membranes to the iris and lens, creating a clear central zone within the visual axis. The settings were fundamental mode, 1.2-to 3.1-mJ energy per shot and 48.3 +/- 20.1 single pulses. Vision improved significantly in six patients, whereas elevated intraocular pressure was observed in one patient. CONCLUSION: Postoperative pupillary membranes may be successfully lysed with use of the Nd:YAG laser.

Aged↗
PubMed1994

Treatment of bleb infection after glaucoma surgery.

OBJECTIVE: To assess the history, clinical course, and response to treatment of 14 patients with a bleb infection (blebitis) following glaucoma surgery. DESIGN: Retrospective study. SETTING: A university referral center in Atlanta, Ga. PATIENTS: Fourteen patients developed a bleb infection that ranged from 1 month to 22 years after glaucoma surgery. Infections were characterized by pain, a whitened bleb surrounded by intense conjunctival injection, marked anterior chamber reaction (hypopyon in six eyes), and a clear vitreous. Before infection, most blebs were described as thin. The results of Seidel's test were positive in six patients, and most patients had a low intraocular pressure without the use of any glaucoma medication. INTERVENTION: Treatment consisted of hospitalization, intravenous antibiotic therapy, and hourly topical fortified cefazolin sodium and gentamicin sulfate. RESULTS: The visual acuity in most patients improved to the level before the bleb infection, with only three eyes losing 2 or more lines of vision. CONCLUSIONS: Bleb infection without vitreous involvement (blebitis) may be a precursor of endophthalmitis. With aggressive treatment, bleb infection appears to have a much better prognosis for visual recovery than endophthalmitis.

Adolescent↗
PubMed1993

Risk of postoperative visual loss in advanced glaucoma.

The incidence of sudden visual loss after an intraocular procedure in patients with glaucoma and visual field defects has been disputed for over a century. We examined the risk of sudden visual loss associated with trabeculectomy in glaucoma patients with advanced visual field defects. Fifty-four filtering operations performed on 44 patients were reviewed. All patients had visual field defects encroaching on or splitting fixation, a visual acuity of 20/100 or better, and a follow-up period of at least two months. Thirty-one of the 54 preoperative visual fields (57%) disclosed a fixation-splitting defect. Sudden visual loss was not observed in any patient during the two-month postoperative period. These findings suggest that the incidence of sudden postoperative visual loss is lower than previously reported.

Adult↗
PubMed1993

The effect of reduced eyedrop size and eyelid closure on the therapeutic index of phenylephrine.

In this study we examined the relative effects of reducing eyedrop size (from 30 microliters to 10 microliters) and eyelid closure on the ocular efficacy and systemic absorption of 10% phenylephrine. Thirteen subjects participated in a quadruple crossover study that involved dilation with a 10-microliters and a 30-microliters drop of phenylephrine with and without eyelid closure. The 10-microliters drop was just as effective for pupillary dilation as the 30-microliters drop. Eyelid closure improved dilation for both drop sizes. Both eyelid closure and reducing the drug volume decreased systemic absorption of phenylephrine as measured by plasma concentration. When used together, eyelid closure and the smaller drop size reduced plasma concentration by 45%. The therapeutic index for 10% phenylephrine appears to be improved by using a 10-microliters drop followed by eyelid closure.

Absorption↗
PubMed1988

Topical beta-blocker therapy and central nervous system side effects. A preliminary study comparing betaxolol and timolol.

Topical beta-blocking agents have been associated with adverse central nervous system (CNS) effects, including depression, emotional lability, and sexual dysfunction. Two studies were done to determine if patients who develop CNS effects while using timolol maleate would improve with betaxolol hydrochloride. In one study, 18 patients with CNS symptoms during timolol therapy were switched to betaxolol. Sixteen of the 18 patients noted symptomatic improvement with betaxolol. The second study involved seven patients with CNS symptoms during timolol therapy who were entered into a double-masked cross-over study. In two patients CNS symptoms resolved with betaxolol; in three patients symptoms improved; and in one patient symptoms worsened with betaxolol. Although factors influencing beta-blocker activity in the CNS are not well understood, there may be some advantage to a selective agent.

Administration, Topical↗
PubMed1988

Internal sclerectomy with an automated trephine for advanced glaucoma.

An automated trephine (trabecuphine) was used to perform an internal sclerectomy in seven glaucoma patients who were aphakic or had undergone previous filtering surgery that had failed or both. A patent fistula was achieved intraoperatively in all seven eyes. Postoperatively, six patients received subconjunctival injection of 5-fluorouracil (5-FI) once daily for an average of 8 days. Five of seven patients have retained a functional bleb and a controlled intraocular pressure (IOP) after surgery (follow-up, 4-24 months). The only intraoperative complication was hemorrhage from the sclerectomy site in a patient with aniridia that resulted in a 20% hyphema. The hyphema cleared quickly, and the bleb has remained functional with a pressure of 12 mmHg for 9 months. The trabecuphine makes it possible to perform a glaucoma filtering operation safely from within the anterior chamber. This technique minimizes conjunctival trauma in the filtration area. The absence of a conjunctival incision overlying the fistula simplifies the adjunctive use of antimetabolites such as 5-FU.

Choroid↗
PubMed1988

ALO 2145 reduces the intraocular pressure elevation after anterior segment laser surgery.

The effect of an alpha adrenergic agonist, ALO 2145 (para-amino-clonidine [PAC]), was examined in a double-masked, multicenter study on the postoperative intraocular pressure (IOP) elevation after laser surgery in 165 patients (83 trabeculoplasty, 36 iridotomy, and 46 capsulotomy). One drop of 1.0% ALO 2145 or vehicle was instilled 1 hour before and immediately after laser surgery. The mean IOP increase in the ALO 2145-treated group was lower (P less than 0.05) than in the placebo group at each of the first three postoperative hours. Overall, 18% of placebo-treated eyes experienced IOP increases greater than or equal to 10 mmHg as compared with 4% of ALO 2145-treated eyes (P less than 0.003). Ocular and systemic side effects were minimal and did not differ between the treatment groups. ALO 2145 safely and effectively reduced the incidence and magnitude of potentially harmful IOP elevations after anterior segment laser surgery.

Aged↗
PubMed1987

Internal sclerectomy for glaucoma filtering surgery with an automated trephine.

A technique is described for performing full-thickness glaucoma filtering operation from within the anterior chamber. The procedure utilizes an automated trephine, designated the "trabecuphine," that is capable of simultaneous cutting and irrigation. The trabecuphine is brought into the anterior chamber through a limbal incision 180 degrees away from the planned filter site. The trephine is passed across the anterior chamber, above the iris, and into the angle to perform the sclerotomy. This procedure was performed successfully in 13 eyes of seven cynomolgus monkeys. Complications included two small hyphemas that cleared completely. Other complications such as flat anterior chamber, corneal damage, iridodialysis, conjunctival buttonhole, and cataract formation did not occur. Internal scleral trephination may offer another alternative in the surgical management of patients with intractable glaucoma.

Animals↗
PubMed1987

Reduction of phenylephrine drop size in infants achieves equal dilation with decreased systemic absorption.

We studied the effect of reducing eye drop size on the efficacy and systemic absorption of topical 2.5% phenylephrine hydrochloride in neonates and infants. Eleven neonates received an 8-microL drop volume in one eye and a 30-microL drop volume (commercial size) in the fellow eye. Mean pupillary dilation at 60 minutes was equivalent (4.86 mm vs 4.57 mm) for both eyes, respectively. The plasma phenylephrine level was determined for the two drop sizes in a second group of infants. Eight infants received an 8-microL drop volume in both eyes, while nine infants received a 30-microL drop volume in both eyes. The mean phenylephrine level at ten minutes was 0.9 ng/mL for the 8-microL drop group and 1.9 ng/mL for the 30 microL drop group. In neonates and infants, reducing the drop volume of topical phenylephrine may improve the risk-benefit ratio.

Absorption↗