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Biomedical subjects

P Nemet

Publications and source records attributed to P Nemet.

At least 19 recordsLinked to original sources
PubMed2000

Medial transposition of the lateral rectus muscle in combined third and fourth nerve palsy.

Surgical treatment of combined third and fourth nerve palsy is a challenging problem in strabismology. Five of the 6 extraocular muscles are paralyzed, which leaves the lateral rectus muscle with no antagonist to counteract its activity and usually results in a maximal exotropia. The goal of surgery is to achieve orthophoria in primary position with limited ductions. Because some believe that a conventional recession-resection procedure will inevitably result in a drift back to exotropia,(1) several other methods have been proposed to treat this disorder. These include temporal mattress suture,(2) eye muscle prosthesis, (3,4) splitting and reattaching the lateral rectus muscle near the vortex veins,(5) and fixation of the eye with fascia lata.(6) Taylor(7) suggested using medial transposition of the lateral rectus muscle in a case of isolated third nerve palsy. We report the outcome of a procedure that included such a transposition for the treatment of combined third and fourth nerve palsy.

Eye Movements↗
PubMed1999

Tono-Pen versus Goldmann tonometry after excimer laser photorefractive keratectomy.

PURPOSE: To compare intraocular pressure (IOP) measurements by the Tono-Pen 2 tonometer and Goldmann applanation tonometer (GAT) in post-photorefractive keratectomy (PRK) patients. SETTING: Refractive Surgery Center, Assaf Harofeh Medical Center, Zerifin, Israel. METHODS: In 18 patients, IOP was measured by GAT and then by Tono-Pen 2 tonometer 2 to 18 months following PRK (mean 6.6 months +/- 5.1 [SD]). Photorefractive keratectomy had been performed in 1 eye of each patient; the fellow eyes served as controls. Corneal curvature and thickness were evaluated. Ten of the 18 patients were treated with topical steroids. RESULTS: In the post-PRK eyes, mean GAT IOP was 1.8 +/- 3.1 mm Hg lower than mean Tono-Pen IOP (P = .012); there was no significant IOP difference in the control (fellow) eyes. In steroid-treated post-PRK eyes, mean GAT IOP (12.2 mm Hg) was 2.2 +/- 1.3 mm Hg lower than mean Tono-Pen IOP (14.4 mm Hg) (P = .0007). Mean Tono-Pen IOP in steroid-treated post-PRK eyes was 4.3 +/- 3 mm Hg higher than in the fellow eyes (P = .0014); mean GAT IOP was only 2.3 +/- 3.5 mm Hg higher (P = .04). In post-PRK eyes without topical steroid treatment, mean GAT IOP was 2.0 +/- 1.18 mm Hg lower than in the fellow eyes (P = .001); there was no significant difference in Tono-Pen IOP. There was a negative correlation between the difference in IOP values (Tono-Pen minus GAT) and corneal curvature in post-PRK eyes (r = 0.76, P = .0108, n = 15). CONCLUSIONS: The Tono-Pen tonometer appeared to be less affected than the GAT by the relative flattening, thinning, and anterior stromal decreased rigidity of the central cornea that occur following PRK. Post-PRK steroid-induced IOP elevation may be masked by the artifactual decrease in GAT IOP.

Adult↗
PubMed1999

Visual acuity tests using chart, line, and single optotype in healthy and amblyopic children.

PURPOSE: The purpose of this study was to evaluate the difference between full chart, single line, and single optotypes visual acuity (VA) test results in healthy and amblyopic children. METHODS: Thirty-five children with amblyopia (20 with strabismus and 15 with anisometropia) and 40 ophthalmologically normal age-matched children were examined. The mean age of the patients in the study and control groups did not differ significantly (P= .9). A commercial projector that projected tumbling-E randomly placed optotypes was used. The VA of the amblyopic eye of the patients in the study group and the right eye of the patients in the control group was examined first using a full chart of optotypes, then using a single line of optotypes, and finally with individual symbols. The procedure was repeated with the other eye. RESULTS: LogMAR VA improved when the full chart was substituted with a single line, and improved by a similar increment further with single optotypes, in both the study and control groups. VA improved significantly more in eyes with amblyopia than in control subjects. Results were not influenced by age. CONCLUSION: VA testing using a single line gives better, sometimes misleading results, than tests with a full chart because it reduces but does not eliminate the crowding effect. When using a device that can employ more than 1 mode, the exacttest mode should be specified and maintained throughout the follow-up.

Amblyopia↗
PubMed1999

Acetylcholine intramuscular injection improves results of inferior oblique myectomy.

PURPOSE: To examine the effect of injecting acetylcholine into the remaining proximal segment of the inferior oblique muscle after distal myectomy. METHODS: Twenty patients with inferior oblique overaction, 11 males and 9 females, were enrolled prospectively in the study: 14 with V type esotropia, 4 with V type exotropia, and 2 with paresis of the superior oblique muscle. At surgery, the inferior oblique muscle was identified, isolated on a muscle hook, cut free at its insertion, and freed of its facial attachments. After a 5 mm myectomy of the distal end the muscle body was then injected with 0.5 cc of acetylcholine (Miocholthorn ). RESULTS: Eighteen out of 20 cases exhibited satisfactory results: postoperatively there was no inferior oblique overaction in 16, consecutive underaction in 2. Mild residual overaction remained in 2 patients. None, however, required additional surgery. CONCLUSIONS: Our experience with injection of acetylcholine to the myectomized inferior oblique shows that it can, by stimulating contraction, enhance withdrawal and recession of the disinserted myectomized muscle and thereby eliminate undesirable reattachment near the original insertion. The end result is a lower incidence of persistence or recurrence of postoperative overaction and improved surgical results.

Acetylcholine↗
PubMed1998

Corneal thickness and curvature in normal-tension glaucoma.

PURPOSE: To determine whether normal-tension glaucoma, defined as a condition in which glaucomatous optic nerve and visual field changes exist without documentation of intraocular pressure greater than 21 mm Hg or other apparent cause for these changes, is overdiagnosed in patients with decreased central corneal thickness and curvature. METHODS: Twenty-one patients with normal-tension glaucoma were compared with 25 patients with primary open-angle glaucoma and 27 age-matched healthy subjects. Corneal thickness was determined by ultrasonic pachymetry. Corneal curvature was determined using a keratometer. Eyes with corneal pathology or previous intraocular surgery were excluded. RESULTS: Mean corneal thickness +/- SD in 21 eyes of 21 patients with normal-tension glaucoma was 0.521 +/- 0.037 mm, significantly (P = .0028) lower than in 25 eyes of 25 patients with primary open-angle glaucoma (0.556 +/- 0.035 mm) and 27 eyes of 27 healthy subjects (0.555 +/- 0.034). Mean corneal curvature in the three groups was not appreciably different: 43.90 +/- 1.81 diopters, 43.66 +/- 1.68 diopters, and 44.36 +/- 1.13 diopters in the patients with normal-tension glaucoma and primary open-angle glaucoma and the healthy subjects, respectively. CONCLUSIONS: Corneal thickness is significantly reduced in patients with normal-tension glaucoma compared with patients with primary open-angle glaucoma (P = .0028) and normal subjects (P = .0037). This may lead to underestimation of intraocular pressure and misdiagnosis in some of these patients. Corneal curvature was similar in patients with normal-tension glaucoma and primary open-angle glaucoma and in healthy subjects.

Aged↗
PubMed1998

Excimer laser photoastigmatic refractive keratectomy: eighteen-month follow-up.

OBJECTIVE: To study the efficacy of photoastigmatic refractive keratectomy (PARK) by the MEL 60 (Aesculap-Meditec, Jana, Germany) scanning excimer laser for the treatment of myopic astigmatism, with follow-up of 18 months. PATIENTS AND METHODS: One hundred and twenty-eight eyes of 102 patients with different degrees of myopic astigmatism were treated by PARK and followed prospectively in an open study. Ablations were performed with an MEL 60 excimer laser using an astigmatic module. RESULTS: Mean preoperative refractive cylinder improved from a preoperative value of -1.8 +/- 0.8 diopters (D; range, -1.0 to -6.0 D) to -0.3 +/- 0.5 D (range, +1.0 to -2.5 D) at 18 months. The mean reduction in cylindrical correction alone was 84 +/- 37% in the low astigmatism group (-1.0 to -1.5 D); 91 +/- 21% in the moderate astigmatism group (-1.75 to -2.5 D); and 75 +/- 25% in the high astigmatism group (-2.75 to -6.0 D). One hundred and three eyes (80%) at 12 months and 100 eyes (85%) at 18 months were within +/-0.5 D of the intended astigmatic correction, with more eyes in the low astigmatic group. One hundred and nineteen eyes (93%) and 114 eyes (97%) at 12 and 18 months, respectively, were within +/-1.0 D of the intended correction. Ninety-two percent to 95.7% of the eyes in the different groups had a postoperative axis less than 10 degrees of the preoperative and intended axis at 12 and 18 months after PARK. Uncorrected visual acuity (UCVA) of 20/40 or better was achieved in nearly 84% of the eyes 12 and 18 months after PARK. A UCVA of 20/20 was achieved in 49% of eyes 18 months after PARK. Ten eyes (8%) underwent reoperation at the end of 12 months. CONCLUSIONS: The data indicate that PARK is an effective surgical tool for correcting astigmatism, especially astigmatism of 1.0 to -2.5 D, with a success rate of approximately 70%.

Adolescent↗
PubMed1998

Excimer laser phototherapeutic keratectomy for recurrent corneal erosion.

PURPOSE: To evaluate the outcome of excimer laser phototherapeutic keratectomy (PTK) for recurrent corneal erosion. SETTING: Laser Institute, Assay Harofeh Medical Center, Zerifin, Israel. METHODS: Twenty-three patients with a mean age of 50.56 years +/- 13.87 (SD) were referred between 1991 and 1995 for recurrent corneal erosion that did not respond to conservative treatment. All were treated by excimer laser PTK. Patients were interviewed and examined before and after treatment. RESULTS: Disease duration ranged from 2 months to 10 years. Frequency of attacks ranged from weekly to three to four times a year. Re-epithelialization of the cornea was established within an average of 3 days after PTK treatment. Follow-up was 12 to 60 months (mean 38.43 +/- 12.08 months). Nineteen (83%) patients were free of recurrences, and 3 had one recurrence treated successfully by patching. One patient who had two recurrences had a second PTK procedure and was symptom free for 14 months. No patient reported reduced visual acuity or quality. Postoperative best corrected visual acuity was unaltered in 21 eyes and improved in 2. There was no significant difference between preoperative and postoperative manifest refractions. CONCLUSION: Excimer laser PRK appears to be a safe and effective treatment for recurrent erosions of the cornea.

Adult↗
PubMed1997

[Laser photorefractive surgery].

As photorefractive keratectomy (PRK) with excimer laser gains world-wide acceptance, more patients are able to discard their spectacles. Our study comprised 611 eyes which underwent PRK and were followed for at least a year. Those with myopia up to -6.00D had better post-operative visual acuity and refraction, than patients with higher grades of myopia. They had less corneal haze and a greater proportion were satisfied with their results. Complaints of halos and glare were similar at all degrees of myopia up to -10.00D.

Follow-Up Studies↗
PubMed1997

For how long can regression continue after photorefractive keratectomy for myopia?

PURPOSE: The presence and degree of regression were assessed from 18 to 30 months after photorefractive keratectomy (PRK). METHODS: A total of 449 eyes (449 patients) were treated with an Aesculap Meditec 193-nm Arf Excimer laser. These 449 eyes were followed during the first 24 months after PRK, and 252 of these eyes were followed for 24 to 30 months. RESULTS: Thirty (6.7%) of the 449 eyes followed for up to 24 months showed good refractive results during the first year and a half but regressed thereafter and required retreatment. Late regression was confined to subjects with pretreatment myopia above -4.0 diopters (D) and was the same in low- and high-myopic eyes between 18 and 24 months post-PRK. However, between 24 and 30 months, regression was higher in low-myopic eyes, where it reached -0.55 D, than in high-myopic eyes, where it was -0.21 D. This lower frequency of regression in high-myopic eyes is attributed to the relatively high rate of retreatment in this group during the first 18 months after PRK. CONCLUSIONS: Although the findings indicate a fairly low rate of regression after 24 months, there still are insufficient data on which to predict when regression post-PRK stabilizes.

Adult↗
PubMed1997

Refractory intraocular pressure increase after photorefractive keratectomy.

A patient with developmental angle anomaly developed a corticosteroid-induced refractory increase in intraocular pressure (IOP) after photorefractive keratectomy (PRK). Trabeculectomy was required to reduce the pressure. Although rare, corticosteroid-induced refractory IOP increase is a serious complication of PRK and may necessitate trabeculectomy. More frequent monitoring of IOP in post-PRK patients and a re-evaluation of postoperative treatment are indicated.

Adult↗
PubMed1997

Influence of patient age on refraction and corneal haze after photorefractive keratectomy.

AIMS/BACKGROUND: Since wound healing processes are known to be more rapid in those who are young, it was decided to examine the effect of patient age on refractive outcome of photorefractive keratectomy (PRK). METHODS: The records of 599 eyes that had undergone PRK were studied retrospectively. The eyes were categorised by baseline myopia and patient age. Spherical equivalent and corneal haze were compared in the baseline refraction and age groups at 3, 6, and 12 months after PRK. RESULTS: There were no differences in postoperative refraction and corneal haze in the different age groups. CONCLUSION: Patient age had no statistically significant effect on refraction and corneal haze 1 year after PRK.

Adult↗
PubMed1997

Results of a repeated excimer laser photorefractive keratectomy for myopia.

BACKGROUND AND OBJECTIVE: As photorefractive keratectomy (PRK) becomes more widely used, the incidence of repeated PRK increases. The present study was conducted to evaluate results of repeated PRK in view of the meager data on this topic. PATIENTS AND METHODS: In this retrospective study, the authors reviewed the records of 1028 eyes that had undergone PRK, and analyzed the results of 66 eyes that required a second PRK for undercorrection according to baseline refraction. RESULTS: A second PRK was performed in 6.3%, 13.7%, and 10.1% of low, moderate, and high myopes, respectively. The mean refraction 1 year after repeated PRK was similar in both myopic groups: less than -1.00 D. Of the low myopes, 87.50% had residual refraction within 1 D after 1 year. Of the moderate myopes, 88.23% had residual refraction within 1 D after 1 year. All of the low myopes achieved uncorrected visual acuity (VA) of 20/25 or better 1 year after repeated PRK, compared with 58.82% of the moderate myopes. Loss of best-corrected VA never exceeded two lines. CONCLUSION: The overall results of PRK appear to be satisfactory.

Adult↗
PubMed1995

Intraocular pressure and blood flow of the optic disk: a fluorescent blood cell angiography study.

The damage to disk microcirculation in glaucoma and ocular hypertension is correlated with the damage to the neuronal tissue. However, it is not clear whether the primary damage is vascular or neurogenic. We have developed a new method which allows in vivo observation of the retinal capillary blood cell flow and the plasma flow, separately. The method was used to examine the blood cell flow in the optic disks of cats' eyes. The intraocular pressure was controlled by extra-fine intraocular canula at the anterior chamber. It was found that blood cell flow became stagnant in a few capillaries at the optic disk with an intraocular pressure of 30-45% of the systemic mean blood pressure. When an induced IOP increase to 45% of systemic mean blood pressure was sustained for 30 minutes, microcirculatory blood flow recovery was complete two hours later. When this pressure was sustained for 120 minutes, the recovery was incomplete two hours later. This work represents a new tool in the research of retinal and disk hemodynamics and microvascular pathologies. The results presented in this paper support the hypothesis that early ischemic microdamage might be the basis of the pathogenesis of the chronic glaucomas.

Animals↗
PubMed1994

Combined timolol and pilocarpine vs pilocarpine alone and timolol alone in the treatment of glaucoma.

We compared the effects of pilocarpine 4% alone, timolol 0.5% alone, and a combination of timolol 0.5% and pilocarpine 4% in the treatment of glaucoma. We treated 43 patients with glaucoma using each drug and then with the combination of drugs for four weeks each. Only patients with a morning intraocular pressure of at least 24 mm Hg without treatment were included. The patients were examined, after one and four weeks of treatment with pilocarpine, timolol, or combined timolol 0.5% and pilocarpine 4%, before the morning dose and at two and five hours after it. At the end of the study, the mean reduction in intraocular pressure from baseline was 9.2 +/- 5.1 mm Hg (28.5% +/- 12.7%) with combined timolol 0.5% and pilocarpine 4%, 5.6 +/- 3.6 mm Hg (17.6% +/- 9.7%) with pilocarpine, and 7.5 +/- 5.0 mm Hg (21.2% +/- 12.6%) with timolol. Intraocular pressure was consistently lower with the combination treatment than with timolol or pilocarpine alone. We believe that this combined solution of timolol-pilocarpine is a valuable contribution to the treatment of open-angle glaucoma.

Administration, Topical↗