Cancer risk among parents and siblings of patients with schizophrenia.

BACKGROUND: A reduced risk of cancer has been noted among people with schizophrenia. Given that genetic causes have been proposed as an explanation of this finding, one would expect that the risk of cancer among first-degree relatives would be equally reduced. AIMS: To investigate the risk of cancer among the biological parents and full siblings of people receiving in-patient care for schizophrenia. METHOD: Linkage analysis was conducted between national population, psychiatric and cancer databases. Standardised incidence ratios for all cancer sites were calculated by comparing the incident rates among first-degree relatives with national incidence rates. RESULTS: A reduced cancer risk was found across all groups examined. Among parents, whose numbers were adequately large, the findings reached statistical significance. For index cases and siblings--a markedly younger population--only a trend was elicited. CONCLUSIONS: The genetic hypothesis--namely, the presence of a gene with the dual effect of reducing the cancer risk and disrupting neurodevelopment--is a plausible explanation for these findings.

Laser in situ keratomileusis to correct hyperopic shift after radial keratotomy.

PURPOSE: To assess the safety and efficacy of excimer laser in situ keratomileusis (LASIK) to correct hyperopic shift following radial keratotomy (RK). SETTING: Ophthalmic Health Center, Tel Aviv, Israel. METHODS: The study comprised 15 eyes of 12 patients who had uneventful RK and subsequently developed a hyperopic shift. Laser in situ keratomileusis was performed using the Chiron Automated Corneal Shaper and the Nidek EC-5000 excimer laser with 5.5 mm central and 7.5 mm peripheral ablation zones. The corneal flap was 160 microm in thickness and 8.5 mm in diameter. The refractive correction corresponded to the patients' refractive errors. RESULTS: The mean time after RK was 10.46 years +/- 2.21 (SD) and the mean follow-up after LASIK, 7.3 months (range 1 to 42 months). The mean spherical equivalent refraction was corrected from +3.08 +/- 1.02 diopters (D) to -0.16 +/- 0.73 D after LASIK. At the last examination, 12 eyes (80%) had a refractive error within +/-1.00 D of emmetropia and an uncorrected visual acuity of 20/40 or better. No wound dehiscence, epithelial ingrowth, or other significant complication developed in any eye. CONCLUSIONS: Early postoperative results of the correction by LASIK of a hyperopic shift after RK are encouraging, but long-term studies of a larger population group are required to evaluate the method's clinical value.

Bilateral comparison of photorefractive keratectomy for myopia using two excimer lasers.

PURPOSE: The aim of this study was to compare the results of excimer laser photorefractive keratectomy (PRK) in patients who underwent PRK using the Summit Apex (Omnimed) excimer laser in one eye and the Nidek EC-5000 excimer laser in the other. METHODS: All consecutive patients who underwent PRK with the Summit Apex laser (Omnimed) in one eye and the Nidek laser (EC-5000) in the second and had at least 12 months of follow-up were included in this retrospective study (n=30). Uncorrected and spectacle-corrected visual acuity, final spherical equivalent refraction, and grade of subepithelial haze were compared. The average preoperative spherical equivalent refraction of eyes treated with the Summit laser was -6.00 D (range, -2.50 to -8.75 D), and for Nidek-treated eyes it was -5.57 D (range, -2.50 to -8.80 D). RESULTS: Forty-seven percent of Summit-treated eyes and 53% of Nidek-treated eyes had uncorrected visual acuity of 6/6 or better; 61% of Summit-treated eyes and 63% of Nidek-treated eyes had uncorrected visual acuity of 6/7.5 or better; 95% of Summit-treated eyes and 95% of Nidek-treated eyes had uncorrected visual acuity of 6/12 or better (difference not statistically significant). Seventy-three percent of eyes treated with the Summit laser and 80% of eyes treated with the Nidek laser had a postoperative refraction within +/-0.50 D of emmetropia; 97% of Summit-treated eyes and 87% of Nidek-treated eyes had a postoperative spherical equivalent refraction within +/-1.00 D of emmetropia; the difference between the two lasers was not statistically significant. However, the percent of eyes with persistent hyperopia was smaller in the Nidek group after 3 months (P=.0062) and after 6 months (P=.07) than in the Summit group. Videokeratography was not done. CONCLUSION: Both lasers were effective with relatively low side effects. No significant difference was found between the two lasers in postoperative uncorrected visual acuity or refractive outcome. Eyes operated with the Nidek laser had less persistent hyperopia and stabilized earlier.

Comparison of photorefractive keratectomy on one eye and laser in situ keratomileusis on the other eye of the same patient.

OBJECTIVE: The aim of this study was to compare the results of excimer laser photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in the same patient. METHODS: All consecutive patients who underwent PRK in one eye and LASIK in the second eye using the same excimer laser (Nidek EC-5000) and had at least 12 months of follow-up were included in this retrospective study (N = 23). Uncorrected and spectacle-corrected visual acuity, final spherical equivalent refraction, and degree of haze were compared. RESULTS: Mean postoperative spherical equivalent refraction in the group of eyes that underwent PRK was +0.73 D (range, -5.50 to +3.50 D). Mean postoperative spherical equivalent refraction in the group of eyes that underwent LASIK was +0.07 D (range, -1.25 to +3.50 D) (P = .046). CONCLUSION: In our study, eyes treated with LASIK had better results than eyes treated with PRK.

Complications of excimer laser photorefractive keratectomy for myopia.

PURPOSE: To evaluate the safety and complication rates of excimer laser photorefractive keratectomy (PRK). SETTING: Assutah Laser Center, Tel-Aviv, Israel. METHODS: This retrospective study evaluated the complication rate after PRK in 825 consecutive patients who had PRK for myopia and had a follow-up of at least 12 months. RESULTS: At 12 months postoperatively, 4.0% of patients suffered from overcorrection and 8.6% from undercorrection. Induced astigmatism developed in 1.4% of all operated eyes. Three percent of the patients had haze, and 3.6% reported glare or halos. Twenty-three eyes (2.7%) lost one line or more of best corrected visual acuity (BCVA). Ptosis developed in 0.4% of the eyes, and 3.5% had a significant increase in intraocular pressure resulting from corticosteroid treatment. There were no complications in 678 eyes (82.5%). CONCLUSION: Eighty-two percent of eyes having PRK did not develop complications. In 18.0% one or more complication, mainly undercorrection, overcorrection, or loss of BCVA, occurred.

An intraocular telescopic lens for macular degeneration.

Age-related macular degeneration is a leading cause of visual loss in adults older than 60 years of age. Once vision has been seriously compromised, the only means of improving visual function are optical devices that produce magnification of images. These devices fall into three categories: (1) high-plus lenses, (2) external telescopes, and (3) a high-minus center intraocular lens combined with external high-plus glasses. The authors designed a new intraocular lens with an entire telescope in its center. In vitro tests were performed to evaluate modulation transfer function, visual field, and optical aberrations. Implantation in cadaver eyes was performed to test the surgical technique and safety. Test results showed that satisfactory modulation transfer function and optic aberration were achieved, and implantation in cadaver eyes was proven to be feasible and safe. It was concluded that a fully implanted intraocular telescopic lens is an effective optical solution for age-related macular degeneration.

Macular hemorrhage after excimer laser photorefractive keratectomy.

We describe three patients with high myopia, 13.0 to 20.0 diopters (D), who had typical myopic macular hemorrhages 1 to 6 months after photorefractive keratectomy (PRK). The hemorrhages eventually resolved, with resultant permanent decrease in vision and pigmentary and atrophic changes in the macula. Highly myopic eyes are predisposed to bleeding in areas of lacquer cracks and to myopic choroidal neovascularization formation. Awareness of potential retinal pathology in patients having PRK and follow-up retinal examinations are warranted.

Excimer laser reablation.

BACKGROUND AND OBJECTIVE: To evaluate the outcome of repeated excimer laser keratectomy after photorefractive keratectomy (PRK). PATIENTS AND METHODS: A retrospective study of 32 of 1000 consecutive patients who had a follow-up of at least 12 months and who underwent repeated PRK in the Assutah Laser Center. RESULTS: The mean spherical equivalent (SE) declined significantly as a result of the repeated treatment. As opposed to zero eyes before re-treatment, 19 of 29 eyes (66%) achieved SE of within +/-1 D 6 months after re-treatment. Before re-treatment, 20 of 32 eyes (62%) had medium or severe haze, whereas after re-treatment only 1 of 29 eyes (3%) had medium haze, and none of the eyes had severe haze. At 6 months after reoperation, visual acuity had improved to 20/36, a significant improvement to the mean log MAR equivalent of 20/40 before re-treatment, yet still significantly worse than the log MAR equivalent before initial ablation which was 20/30. CONCLUSION: Repeated excimer laser PRK has the potential for successful treatment of undercorrection, regression, and haze occurring after an initial PRK.

Patient satisfaction after 5.0-mm photorefractive keratectomy for myopia.

PURPOSE: To examine patient satisfaction following photorefractive keratectomy (PRK) in a large number of subjects. METHODS: We used a questionnaire to examine overall patient satisfaction in 173 patients (173 first-operated eyes) at least 1 year after they had undergone PRK. Mean preoperative spherical equivalent refraction was -7.05 +/- 3.73 D (range, -1.50 to -15.00 D). Fifty-one patients had unilateral surgery and 122 had bilateral surgery, 60 of whom had follow-up of 1 year for both eyes. Visual and refractive results, the use of corrective lenses, and subjective side effects were also studied. RESULTS: Eighty percent of 173 patients reported they were satisfied or very satisfied with the surgical outcome, while 19.7% reported they were dissatisfied. The average satisfaction score was 7.92 +/- 2.22 out of a possible 10. After PRK, 77.5% reported improvement or great improvement in their general quality of life; 16.8% were very disturbed by subjective visual symptoms. Of the 51 bilateral patients, 85% required no corrective lenses after surgery. Patients who had bilateral operations were more satisfied than those who had unilateral ones. Statistically significant associations were found between patient satisfaction and initial refraction: as preoperative refraction increased, percentage of satisfied or very satisfied patients decreased. CONCLUSION: Patient satisfaction after PRK was generally high, but subjective visual symptoms remain a problem.

Late onset corneal haze after photorefractive keratectomy for moderate and high myopia.

BACKGROUND: Corneal haze after photorefractive keratectomy (PRK) usually appears within 4 weeks after the procedure. A new type of corneal haze, starting relatively late after PRK, is reported. METHODS: The authors reviewed the files of their first 1000 consecutive patients who completed a follow-up of 12 months or more and identified all those who had clear corneas for at least 4 months, after which corneal haze appeared. The clinical course in these patients was evaluated. RESULTS: Late onset corneal haze (LOCH) had occurred in 18 eyes of 17 patients (incidence, 1.8%), appearing 4 to 12 months after PRK and resulting in decreased visual acuity and regression. Treatment with topical steroids or reoperation resulted in partial reversibility of haze and regression. CONCLUSIONS: A new entity of LOCH is described. The appearance of LOCH suggests that corneal healing and remodeling continue for at least 1 year after PRK.

Influence of patient age on photorefractive keratectomy for myopia.

BACKGROUND: To determine whether the outcomes of photorefractive keratectomy (PRK) for myopia are age-dependent. METHODS: The influence of age on PRK outcomes was analyzed for one eye of each of 72 patients divided into two groups: 39 patients (18 to 26 years) and 33 patients (35 to 54 years). The influence of the amount of preoperative myopia (low myopia less than -4.00 diopters (D); moderate to high myopia -4.00 or more D) was also evaluated. All patients were followed for at least 1 year, and all underwent cycloplegic refractions. RESULTS: One year after PRK, the average refraction was -0.15 D in the younger group and +0.38 D in the older group. The achieved refraction was higher than the attempted by +1.00 D or more only in eyes with moderate to high myopia (-4.00 to -10.00 D); 11.54% (3 eyes) of the younger group and in 34.78% (8 eyes) of the older group. CONCLUSIONS: After PRK for myopia, patients between the ages of 35 and 54, with moderate to high myopia, obtained more refractive change with the same intended dioptric correction compared to younger patients with moderate to high myopia. Attempted correction should be adjusted according to age and amount of myopia.

Cutting the cornea with a waterjet keratome.

BACKGROUND: Waterjet cutting is an advanced technology. It consists of a cutting tool that uses a very thin stream of ultra-high-pressure water forced at high velocity through a very small nozzle, creating a very sharp knife. We report on the first experimental use of waterjet technology to reshape the cornea. METHODS: The system was used in vitro on 10 bovine eyes, and in vivo on 10 albino rabbit eyes. Using the waterjet keratome (Lipshitz-Bass knife, LBK) lamellar corneal incisions were performed. Histological examinations were performed. RESULTS: A waterjet stream was found to be capable of incising corneas at relatively low energy levels (4000 PSI). Good surface quality could be obtained, and there was no collateral damage to the remaining portion of the cornea, lens, or retina. In the in vivo experiments, the epithelium healed within 48 hours. CONCLUSIONS: These preliminary experiments suggest that waterjet technology can be an effective instrument for reshaping the cornea.

The effect of spherical photorefractive keratectomy on myopic astigmatism.

The aim of this report is to present the effects of spherical photorefractive keratectomy (PRK) by excimer laser on myopic astigmatism. Spherical PRK was performed in 96 eyes with myopia associated with astigmatism of between 0.75 and 2.00 diopters (D) using the Summit excimer laser. The reduction both in sphere and in cylinder was found to be highly statistically significant (P < 0.0001 for both). The mean reduction of cylinder was 46%. Astigmatic error of less than 2.00 D can be corrected significantly by spherical PRK.

Symmetry of outcome after photorefractive keratectomy for myopia.

The aim of this study was to find out whether the outcome of excimer laser photorefractive keratectomy (PRK) in the second eye can be predicted from the results of the first, and to determine whether we should modify our therapeutic approach to the second eye according to the results of the first. Bilateral PRK was performed in 73 patients using the Summit Technology excimer laser. All patients included in this study had a follow-up of at least 12 months in both eyes. The change of refraction and the haze of the two eyes were compared. Sixty percent of patients had a difference in refraction between the two eyes smaller than 0.50 diopters (D), and 75% had a difference smaller than 1.00 D. The degree of symmetry in response to treatment was greater in patients with a preoperative spherical equivalent refraction of less than -6.00 D. Most patients had a similar degree of haze in both eyes. The results of our study demonstrate that a considerable degree of symmetry in the outcome of surgery exists between the two eyes of the same patient undergoing PRK, especially in low to moderate myopia.