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Biomedical subjects

Peter Shah

Publications and source records attributed to Peter Shah.

8 recordsLinked to original sources

Vitrectomy-phacoemulsification-vitrectomy for the management of aqueous misdirection syndromes in phakic eyes.

OBJECTIVE: To describe vitrectomy-phacoemulsification-vitrectomy, a sequential 3-step surgical approach, in the management of malignant glaucoma/aqueous misdirection syndromes in phakic eyes. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Five eyes (4 angle-closure glaucoma and 1 open-angle glaucoma) of 5 patients with mean age of 66 years (range, 56-78). Four patients presented with aqueous misdirection syndrome and 1 patient presented for cataract extraction, having previously had malignant glaucoma in the fellow eye after phacoemulsification surgery. INTERVENTION: The operation performed had three steps: vitrectomy, phacoemulsification, and vitrectomy. Step 1: Preliminary vitrectomy involved limited core vitrectomy to "debulk" the vitreous and soften the eye. Step 2: Phacoemulsification was performed in a standard manner. Step 3: Residual vitrectomy, zonulohyaloidectomy and peripheral iridectomy (if not already present) were performed to create a free communication between the posterior and anterior segments. MAIN OUTCOME MEASURES: Intraocular pressure, visual acuity, biomicroscopic anterior chamber depth, and complications. RESULTS: The time interval between the onset of malignant glaucoma and surgery ranged from 2 weeks to 3 months. All 4 patients with aqueous misdirection syndrome had relief of the aqueous misdirection postoperatively with anterior chamber deepening. Intraocular pressures on day 1 ranged from 6 to 28 mmHg (mean 15.6, mmHg), and at the last visit ranged from 8 to 30 mmHg (mean, 20.4 mmHg). One eye developed an early choroidal serosanguinous effusion requiring drainage. CONCLUSIONS: The vitrectomy-phacoemulsification-vitrectomy approach was effective in this pilot series in the management of aqueous misdirection syndromes and malignant glaucoma in phakic eyes.

Aged↗

Phacoemulsification, persistent hypotony, and cyclodialysis clefts.

A retrospective noncomparative case-note analysis of 3 men presenting with persistent hypotony after routine phacoemulsification cataract surgery was performed. All patients had a previous history of significant blunt ocular trauma. All patients had surgical repair of the cyclodialysis clefts, 1 with cleft cryopexy and 2 with formal cleft closure with a limbal-based double scleral flap technique. All patients achieved closure of the cyclodialysis clefts following surgical intervention with complete resolution of hypotony. Mean preoperative intraocular pressures improved from 3, 4 and 3 mm Hg in the 3 cases to 11, 16, and 17 mm Hg postoperatively. Visual acuities improved from preoperative readings of counting fingers, 6/36 and 6/24 in the 3 cases to 6/6, 6/9, and 6/9 postoperatively. Persistent hypotony because of possible activation of a preexisting doormant cyclodialysis cleft following routine atraumatic phacoemulsification cataract surgery in previously traumatized eyes has not been reported.

Adult↗

Diode laser cyclophotocoagulation: role in the management of refractory pediatric glaucomas.

PURPOSE: To report the efficacy and complications of diode laser cyclophotocoagulation (cyclodiode) in the management of refractory pediatric glaucomas. DESIGN: Noncomparative interventional case series. PARTICIPANTS: Pediatric patients with uncontrolled glaucoma. Seventy-seven eyes of 61 patients underwent cyclodiode. Mean age was 7.4 years (range, 0.4-17 years). MAIN OUTCOME MEASURES: Intraocular pressure (IOP), visual acuity, complications. RESULTS: Diagnoses included aphakic glaucoma, congenital glaucoma, juvenile chronic arthritis, aniridia, anterior segment dysgenesis, and Sturge-Weber syndrome. Sixty percent of eyes were aphakic, and 64% had undergone at least one previous surgical procedure for glaucoma. Patients underwent a mean of 2.3 treatment sessions per eye (maximum, 8 sessions). Mean pretreatment IOP was 32.0 mmHg. After one treatment session, 62% had a clinically useful reduction in IOP (<22 mmHg or by 30%), but this had fallen to 37% by 12 months. With repeat cyclodiode, 72% had a clinically useful reduction in IOP for a year or more (mean, 8.4-month interval between treatments). Aphakic eyes had a more sustained IOP reduction (P < 0.01 log rank test). Of treatment failures, 13% had no useful IOP response, and three eyes developed subsequent retinal detachment and loss of vision. No other eyes lost vision because of cyclodiode-related complications. In 5.5% of the treatment sessions there was a significant posttreatment inflammatory episode. Cyclodiode treatment did not enable a reduction in the number of medications. CONCLUSIONS: With repeated treatment, cyclodiode can provide effective control of IOP. However, the success rate is lower than with adults, and younger eyes may recover from treatment more rapidly. Although response may be temporary, cyclodiode has a lower rate of severe adverse effects than surgical modalities and has roles as a temporizing measure, as an adjunct to surgery, or in managing selected patients in whom surgery is undesirable because of a high risk of surgical complications.

Adolescent↗

The corneal thickness and intraocular pressure story: where are we now?

A review of the current literature was conducted regarding the effect of corneal thickness on the diagnosis of glaucoma, and the influence of excimer laser refractive surgery on intraocular pressure (IOP) measurement with Goldmann applanation tonometry. In general, normals and primary open angle glaucoma patients have a similar distribution of corneal thickness; however, there is a wide variation, ranging from 427 to 716 micro m. Normal tension glaucoma patients have a tendency towards thinner corneas than normals; however, there is an overlap of thickness measurements of more than two-thirds in 95% of patients. There is a trend for ocular hypertensives to have thicker corneas than normals, but again there is an overlap of about one-third in 95% of patients. The general trend after excimer laser refractive surgery is for a decrease in IOP, with a mean fall in IOP measured of 0.63 mmHg per dioptre correction. There is, however, a large scatter of values with some patients having the same or lower IOP post-laser, but with other patients measuring higher pressures. Corneal thickness can influence IOP measurement by Goldmann applanation tonometry; however, the magnitude of the effect is subject to much individual variation.

Cornea↗