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Biomedical subjects

R J Olk

Publications and source records attributed to R J Olk.

At least 19 recordsLinked to original sources
PubMed1992

Pneumatic retinopexy perfluoroethane (C2F6) in the treatment of rhegmatogenous retinal detachment.

Due to differences in expansile properties and duration, perfluorethane gas may offer advantages over other gases presently used for pneumatic retinopexy. Seventeen eyes with retinal detachments with single retinal breaks or groups of breaks no greater than 1 clock hour in extent were prospectively treated with perfluoroethane gas injection and retinocryopexy and followed up for a minimum of 6 months. Twelve eyes (71%) were attached with one procedure, and five eyes (29%) were attached with two or three procedures. Post-operative proliferative vitreoretinopathy occurred in two eyes (12%), new or missed breaks in three eyes (18%), and premacular fibroplasia in one (6%) eye. No eyes had an apparent progression of cataracts. Seven (88%) of eight eyes with preoperative macular detachments had improved visual acuity after surgery. All nine eyes (100%) with preoperative macular attachment had the same or improved visual acuity after surgery. The efficacy of perfluoroethane appears similar to that of other perfluorocarbon gases.

Fluorocarbons↗
PubMed1991

Modified grid laser photocoagulation for diffuse diabetic macular edema. Long-term visual results.

The authors reviewed the records of 302 eyes of 185 patients with diffuse diabetic macular edema with or without cystoid macular edema treated with modified grid laser photocoagulation between the years 1981 and 1990. Three years after initial grid treatment, visual acuity was improved in 14.5%, unchanged in 60.9%, and worse in 24.6% of eyes. The average number of treatments per eye was 1.9. These results show that in assessing long-term visual outcome, modified grid laser photocoagulation is an effective modality in maintaining or improving visual acuity in eyes with diffuse diabetic macular edema. The effectiveness demonstrated in this study is without comparison with control subjects with no treatment or comparison with other treatment techniques.

Adult↗
PubMed1991

Vitrectomy for premacular fibroplasia. Prognostic factors, long-term follow-up, and time course of visual improvement.

Two hundred seventy eyes with premacular fibroplasia consecutively treated by pars plana vitrectomy and membrane peeling were reviewed. This study is among the largest series with long-term follow-up reported to date. Visual improvement of two or more lines was achieved in 43% of eyes at 6 to 12 months, in 54% at 1 to 2 years, in 60% at 2 to 3 years, and in 58% at 3 to 5 years. Overall, complications occurred in 34 eyes (13%). Cataract progression after vitrectomy was noted in 106 (57%) of phakic eyes at 3 to 5 years, and 43 of these eyes underwent subsequent cataract extraction. Mean time to best visual acuity after vitrectomy was slightly less than 1 year for all eyes unless they had cataract worsening with subsequent cataract extraction (1.9 years). Significant factors affecting visual outcome were: preoperative lens status, visual acuity before vitrectomy, duration of preoperative symptoms of distortion and/or blurred vision, and the occurrence of intraoperative complications.

Adolescent↗
PubMed1991

External argon laser drainage of subretinal fluid using the endolaser probe.

The results of 200 consecutive scleral buckling procedures in which the argon endolaser probe was used to create a choroidotomy for drainage of subretinal fluid are reported. This technique was used in any case requiring drainage and was specifically employed in cases in which needle drainage was contraindicated because the detachment was shallow. The argon laser was set at 0.2 seconds, 1.25 watts, and was used with the endolaser probe held adjacent to, but not touching, the choroid. Drainage was successfully accomplished in 98% of cases. Rates of subretinal hemorrhage, retinal incarceration, and perforation related to laser drainage were 5.5%, 2.5%, and 1%, respectively. No large or submacular subretinal hemorrhages occurred. This technique appears to be particularly promising for drainage of shallow retinal detachments.

Choroid↗
PubMed1991

Central serous choroidopathy in patients over 50 years of age.

Reviewing all records of patients with the diagnosis of central serous choroidopathy (CSC) at Retina Consultants, Ltd since 1975, we identified 47 patients with CSC who were older than 50 years at initial presentation. These patients were divided into three groups, based on type of management: observation; light "CSC-type" photocoagulation; and heavy "subretinal-neovascular-membrane (SRNVM)-type" photocoagulation. Although most of these patients retained excellent central visual acuity, overall final visual acuities were poorer than those in other reported series. Heavier photocoagulation, as compared with lighter treatment, was associated with a decreased incidence of posttreatment SRNVM formation and appeared to have no adverse effect on final visual outcome. Patients with multiple irregular leaks on fluorescein angiography had a greater tendency to develop SRNVMs, with or without treatment. Ophthalmologists diagnosing CSC in patients over age 50 should be aware that there is a greater risk of SRNVM developing in these patients.

Age Factors↗
PubMed1990

Safety of fluorescein angiography during pregnancy.

We sent 424 retina specialists questionnaires on fluorescein angiography performed on pregnant women; 399 specialists responded. Of these, 309 (77%) had never performed fluorescein angiography on a pregnant woman. Ninety specialists (23%) had performed at least one fluorescein angiogram on a pregnant woman; detailed information was obtained on 105 patients. Authors of previous reports that included fluorescein angiography during pregnancy provided information about an additional 11 patients. Substantiated side effects were nausea or vomiting in seven patients. Anomalies at birth, an undescended testicle and syndactyly, were reported in two children. There was one stillbirth with pathologic findings classic for toxemia, and one fetal death occurred several months after fluorescein angiography. One therapeutic abortion was performed for complications in toxemia. One spontaneous abortion occurred three days after fluorescein angiography in a patient who was four weeks pregnant. Eight children born to toxemic mothers had low birth weights. We conclude that fluorescein angiography does not cause a high rate of birth anomalies or complications during pregnancy.

Abnormalities, Drug-Induced↗
PubMed1990

Argon green (514 nm) versus krypton red (647 nm) modified grid laser photocoagulation for diffuse diabetic macular edema.

Between 1984 and 1988, 225 eyes of 132 patients were entered in a prospective, randomized clinical trial to determine if any significant differences exist between treatment with argon green (514 nm) and krypton red (647 nm) modified grid laser photocoagulation for patients with diffuse diabetic maculopathy with or without cystoid macular edema. At the 12- and 24-month follow-up visits, no statistically significant difference was found between the two groups with respect to all of the following: reduction or elimination of macular edema, improvement in visual acuity, worsening of visual acuity, number of treatments per eye, and effect on the visual field. At the 12-month follow-up visit, none of the following factors statistically affected the visual outcome in either of the two groups: a history of systemic hypertension, systemic vascular disease, cystoid macular edema, or initial poor visual acuity.

Adult↗
PubMed1989

Choroidal neovascular membrane and other chorioretinal complications of acquired syphilis.

We reviewed ten patients who had posterior segment complications of acquired syphilis. Five of these patients had a neovascular membrane of the choroid associated with secondary or tertiary syphilis. Vision was stabilized after laser photocoagulation in one patient who had a choroidal neovascular membrane. Five additional patients had ocular manifestations including uveitis, optic neuritis, neuroretinitis, chorioretinitis, retinal hemorrhages, arterial and venous occlusion, vasculitis, and retinitis. Treatment of chorioretinal complications of syphilis with intravenous penicillin, if initiated early in the course of the disease, may result in excellent visual recovery.

Adult↗
PubMed1988

Surgical management of premacular fibroplasia.

The results of pars plana vitrectomy and membrane peeling for premacular fibroplasia (PMF) were reviewed retrospectively for 88 eyes of 86 patients. Premacular fibroplasia was idiopathic in 61 eyes (69%) and postdetachment in 27 eyes (31%). All patients had a minimum follow-up of 12 months. Visual symptoms of blurring and metamorphopsia were reduced in 75 (85%) study eyes at the end of the follow-up period. Poor visual outcome was significantly related to preoperative cystoid macular edema and prolonged duration of visual blurring. Posterior retinal breaks occurred in three eyes (5%) with idiopathic PMF and five eyes (19%) with postdetachment PMF. Cataract progression was demonstrated in 35 eyes (48%) at 12 months of follow-up and 49 eyes (68%) at 24 months of follow-up, reflecting an incidence of cataract formation that has not been previously reported (to our knowledge) after limited vitrectomy and membrane peeling for PMF.

Adult↗
PubMed1988

Modified grid laser photocoagulation for diabetic macular edema. The effect on the central visual field.

Modified grid laser photocoagulation has been shown to stabilize visual acuity in patients with diabetic macular edema, but the effect on extrafoveal visual function is uncertain. Automated static threshold perimetry was performed on 64 eyes of 36 patients before and after modified grid therapy with the argon green or krypton red laser. Twenty-eight eyes underwent two grid treatments for persistent macular edema. For all eyes tested, average threshold sensitivity in the central 5 degrees dropped 3.44 dB (standard deviation [SD], 3.79 dB) after the first treatment and 6.86 dB (SD, 5.02 dB) cumulatively after the second treatment. Qualitatively, the grayscale displays of the central visual field were darker after treatment, but the scotomata from laser photocoagulation could not be distinguished from those due to macular edema. The foveal threshold showed no significant change. In a subgroup of patients tested, color vision was not significantly improved and nearly all patients exhibited a tritan defect before and after treatment. No difference was detected between the argon and krypton groups. This suggests that with modified grid laser photocoagulation visual acuity and foveal threshold are preserved at the expense of generalized loss of threshold sensitivity across the central 10 degrees of the visual field.

Color Perception↗
PubMed1988

Ocular dangers in the garden. A new menace--nylon line lawn trimmers.

Nylon line lawn trimmers represent a source of potentially devastating ocular trauma. Five cases of ocular trauma associated with the use of line trimmers are reported. These case reports document new mechanisms and circumstances of injury, including trauma from debris other than nylon line fragments and injury to bystanders. Furthermore, injuries are often serious, with two of these patients requiring an evisceration or enucleation after endophthalmitis developed. In one patient, six different organisms were cultured and another patient exhibited an Aspergillus organism and Propionibacterium acnes. As nylon trimmers gain in popularity, they will become an increasingly frequent source of ocular injury. A retrospective 40-month review of 85 cases (87 eyes) of penetrating and perforating ocular trauma shows line trimmers to be the fifth leading cause of such injury.

Accidents, Home↗
PubMed1988

Anterior segment ischaemia following laser photocoagulation in a patient with systemic lupus erythematosus.

The authors report the occurrence of occlusive retinal arterial disease and retinal neovascularisation in a 44-year-old woman with systemic lupus erythematosus (SLE). Two days after uncomplicated panretinal photocoagulation the patient developed an acute anterior segment ischaemic syndrome. To our knowledge this complication has not been reported in any other patient following laser photocoagulation or in association with SLE.

Adult↗