Volker Seiberth

Risk factors in retinopathy of prematurity : A multivariate statistical analysis

Objective: To analyze risk factors in retinopathy of prematurity (ROP). Patients and Methods: Four hundred forty-seven surviving very-low-birth-weight infants (birth weight ≤1,500 g) were enrolled in a retrospective study. Clinical data underwent multivariate analysis using stepwise logistic forward regression. Results: For 402 of the babies a complete dataset of 38 possible risk factors was available. Multivariate analysis showed 10 factors to be independently significant variables. Low birth weight, low gestational age, artificial ventilation for more than 7 days, high volume of blood transfusion and surfactant therapy were risk factors associated with higher rates of ROP. Necrotizing enterocolitis, maternal pre-eclampsia, lung maturation by antepartum betamethasone application, vitamin E and phototherapy were accompanied by a lower incidence of ROP. Conclusions: This study confirms several risk factors recognized by previous statistical analysis. In addition, this study reveals maternal pre-eclampsia, which is associated with chronic intrauterine stress, as a statistically independent factor and as having an influence on the incidence of ROP.

Laser in situ keratomileusis to correct myopia of -6.00 to -29.00 diopters.

BACKGROUND Photorefractive keratectomy can cause corneal scarring and visual loss in highly myopic eyes. We evaluated laser in situ keratomileusis (LASIK) because it has the theoretical advantage of preserving both the corneal epithelium and Bowmans layer. METHODS In a prospective study, LASIK was performed in 62 myopic eyes (42 patients) using the Automatic Corneal Shaper (Chiron Vision) and the Keracor 116 excimer laser (Chiron Technolas). We measured refraction and visual acuity, and evaluated corneal topography (TMS 1) and corneal clarity after 4 to 8 weeks and 4 to 6 months. RESULTS Four- to 6-month follow up was completed in 51 eyes. The mean preoperative spherical equivalent refraction was -14.80 diopters (D) (range, -6.00 to -29.00 D). Postoperatively, the mean deviation from the target refraction was -1.70 D (range, -9.00 to +2.50 D) at 4 to 8 weeks and -1.90 D (range, -9.50 to +2.25 D) at 4 to 6 months. At 4 to 6 months, 19 eyes (37%) were within +/- 0.50 D of the target refraction, 24 (47%) within +/- 1.00 D, 33 (65%) within +/- 2.00 D, and 40 (78%) within +/- 3.00 D. From 4 to 8 weeks to 4 to 6 months, the mean regression of myopia was -0.20 D (0.50 D or less in 24 eyes [47%], 1.00 D or less in 32 [63%], and 2.00 D or less in 42 [82%]). In six eyes (12%), the stromal interface was not visible, in 38 (74%) it was barely visible, and in seven (14%) it was clearly visible. Corneal topography revealed only small variations in clear-zone size and dioptric value, demonstrating a very stable correction 4 to 6 months postoperatively. CONCLUSIONS LASIK may be a safe and effective procedure to correct high myopia. Further research is required to develop satisfactory microkeratome technology, effective laser algorithms, and to determine long-term stability of refraction.

Evaluation of contrast acuity and defocus curve in bifocal and monofocal intraocular lenses

ABSTRACT We compared visual quality of the following intraocular lenses in a prospective study: monofocal, True Vista bifocal, 3M diffractive bifocal, and Nordan aspheric VariFocal silicone. Four to six months postoperatively we measured distance acuity, Snellen near acuity (Lighthouse chart), reading acuity (Nieden chart), and contrast acuity at far and near focus (Regan charts: 96%, 50%, 25%,11 % contrast) with different pupil sizes. A defocus curve was obtained by spectacle defocus (+1 diopter [D] to −5 D). Eleven patients had True Vista in one eye and monofocal in the fellow. Contrast acuity at far focus decreased with decreasing contrast and increasing pupil size. This decrease was more pronounced with the True Vista than with the monofocal lenses. These differences were significant, with a 4.5 mm pupil at lower contrast (25%, P = .02; 11 %, P = .01). Depth of focus was 4.5 D (+1.0 D to −2.0 D) with True Vista lenses and 2.5 D (+1.0 D to −1.5 D) with monofocal lenses. Corrected distance acuity was 20/22 with True Vista, 20/25 with 3M, and 20/20 with VarIFocal. Distance corrected Snellen near acuity was 20/39 with True Vista, 20/34 with 3M, and 20/57 with VariFocal. Distance corrected reading acuity was 20/29 with True Vista, 20/23 with 3M, and 20/44 with VariFocal (P = .005). Contrast acuity at far focus was best with the VariFocal IOL, followed by True Vista and 3M. At near focus it was best with 3M, followed by True Vista and VariFocal. Contrast acuity at near focus was lower than at far focus. Average acuity differences were as follows: VariFocal 0.43, P = .01; True Vista 0.19, P = .05; 3M 0.04, P = .3. Depth of focus was 4.5 D (+1.0 D to −3.5 D) with True Vista and 3M and was 3 D (+1.0 D to −2.0 D) with VariFocal. Each design offers unique features. VariFocal is best at distance, but near vision is not sufficient. The 3M lens is best at near vision but distance contrast acuity is somewhat reduced. The True Vista lens provides a good compromise as distance contrast acuity is good and near vision is sufficient.

Comparison of the optical and visual quality of poly(methyl methacrylate) and silicone intraocular lenses

ABSTRACT We evaluated experimentally the optical quality of poly(methyl methacrylate) (PMMA) (Storz 681JV, AMO PC58) and silicone (AMO S119, Adatomed 90D) intraocular lenses (IOLs) and compared the results with our clinical data. We measured surface and image quality using the Zygo laser interferometer and modulation transfer function (MTF) using the Ealing EROS MTF analyzer. Contrast acuity was tested clinically with glare and without glare (Regan charts); AMO PC58, n = 18; AMO SI19, n = 7; Adatomed 90D, n = 18). Modulation transfer function and image quality were slightly better with PMMA IOLs but the reduction of MTF with silicone lenses was within the 1/a diopter defocus range. Surface quality of silicone IOLs was superior to that of PMMA IOLs. Contrast acuity measured clinically was also slightly better with PMMA IOLs at low contrast and with glare but differences were not significant. Our results suggest that optical and visual quality of silicone IOLs is slightly lower than with PMMA IOLs. Experimental and clinical results correlated closely. However, the small differences observed are unlikely to be significant clinically.

Function of the diabetic retina after panretinal argon laser photocoagulation. Influence of the intensity of the coagulation spots.

To investigate the influence of the intensity of coagulation spots on retinal function and the clinical course after panretinal argon laser photocoagulation in diabetic retinopathy, we conducted a prospective study in 24 eyes of 12 diabetics. One eye was treated with moderate spots (average: 300 mW), the fellow eye was coagulated with intense spots (average: 600 mW). The spot size was identical in both eyes. Subjective parameters (visual acuity, perimetry), as well as objective functions (ERG, EOG) and the clinical course, were studied preoperatively and on a regular base with a follow-up of 12 months. Visual acuity and fundus findings deteriorated less often in eyes coagulated with intense spots. Visual field loss, however, was more prevalent in eyes treated with intense spots. Early treatment complications only occurred with high-energy coagulation. For this reason, high-energy spots should not be used even though they might be indicated theoretically.

Diode laser photocoagulation for stage 3+ retinopathy of prematurity.

Abstract• Background: Laser photocoagulation in retinopathy of prematurity (ROP) appears to have fewer adverse effects than cryotherapy and seems to be at least as effective. • Methods: To evaluate the efficacy and safety of diode laser photocoagulation, we included 42 eyes with stage 3+ ROP of 24 preterm infants (gestational age 24–29 weeks, mean ± SD 26.6 ± 1.3 weeks; birth weight 480–1400 g, 896 ± 196 g) in a prospective clinical study. Photocoagulation treatment was performed using a diode laser (810 nm) with a laser indirect ophthalmoscope delivery system. Follow-up ranged from 3 to 16 months (8.8 ± 4.0 months). • Results: In 39 (93%) of 42 eyes ROP regressed after a single laser treatment and the outcome was a flat, attached retina. One eye (2%) had a second laser session and another eye (2%) had additional retinal detachment surgery, resulting in the regression of ROP and a flat, attached retina. Thus, the success rate was 41 (98%) out of 42 eyes. In one (2%) of the 42 eyes treatment failed and ROP progressed to stage 5, although additional retinal detachment surgery was performed. No adverse side effects of diode laser treatment were noticed except for a small amount of retinal/preretinal bleeding in the ridge in five eyes (12%) and a small postoperative anterior chamber hemorrhage in one eye (2%) with dense tunica vasculosa lentis. Neither lenticular opacities nor cataract formation were encountered. • Conclusion: Diode laser photocoagulation for stage 3+ ROP showed only minor side effects and was at least as effective as cryotherapy treatment.

Refractive Errors after Cryotherapy in Retinopathy of Prematurity

Because of acute retinopathy of prematurity 14 premature infants (900-1,630 g birth weight) were treated with cryocoagulation (10 children, both eyes; 4 only one eye) between 1976 and 1984 and were followed up until they were 2-7 years of age. The average refractive power of 20 eyes (those in which refraction could be determined) was -1.5 +/- 4.1 dptr. Twelve eyes (60.0%) were hyperopic (average: +1.3 +/- 0.4 dptr), and 8 eyes (40.0%) were myopic (average: -5.7 +/- 3.6 dptr). Three eyes in which cryocoagulation was done twice or three times because of a severe course developed pronounced myopia (greater than 7.0 dptr). When comparing both eyes of 4 children in whom cryotherapy had been carried out in only one eye, cryotherapy was found to have no influence on refractive errors (average anisometropia +0.4 +/- 0.4 dptr).

Panretinal photocoagulation in diabetic retinopathy: argon versus dye laser coagulation

The range of wavelengths used in ophthalmic photocoagulation treatment has been greatly enlarged by the development of the dye laser. To investigate the efficacy and possible side effects of orange dye laser light in the treatment of diabetic retinopathy, we performed a prospective, controlled clinical study comparing argon blue-green and orange dye laser light. In 14 patients with diabetic retinopathy of equal severity in both eyes one eye was randomly assigned to either blue-green argon (488 and 514.5 nm) or orange dye (600 nm) panretinal laser treatment. The total coagulated area was the same in both eyes. Subjective parameters (visual acuity, perimetry, color vision) as well as objective functions (electroretinography, electro-oculography) and the clinical course were studied preoperatively and then postoperatively over a period of 6 months. Dye laser coagulation proved as effective and safe as blue-green argon laser coagulation in the panretinal treatment of diabetic retinopathy. No significant differences in postoperative retinal function were detected. However, orange laser coagulation proved significantly more painful than bluegreen argon laser treatment (P=0.002).

Diode Laser Photocoagulation for Threshold Retinopathy of Prematurity in Eyes With Tunica Vasculosa Lentis

PURPOSE To determine possible side effects of diode laser photocoagulation for threshold retinopathy of prematurity in eyes with tunica vasculosa lentis. METHODS In a prospective clinical study, threshold retinopathy of prematurity was treated in 14 eyes of seven consecutive preterm infants with tunica vasculosa lentis (birth weight, 480 to 980 g; mean +/- S.D., 777 +/- 175 g; gestational age, 24 to 27 weeks; mean +/- S.D., 25.7 +/- 0.9 weeks) by using the diode laser indirect ophthalmoscope. Main outcome measure was the incidence of adverse treatment effects. Follow-up included anterior segment examination with a hand-held slit lamp and ranged from seven to 17 months (12.6 +/- 3.5 months). RESULTS The tunica vasculosa lentis did not interfere with photocoagulation in any of the 14 eyes. Laser power ranged from 200 to 400 mW (260 +/- 52 mW). Duration of a single spot was 200 msec. Number of burns ranged from 1,060 to 2,132 (1,556 +/- 315). Retinopathy of prematurity regressed in all eyes, and the outcome was a flat, attached retina. A small amount of postoperative anterior chamber bleeding was noticed in one eye (7% of the eyes, 14% of the patients). There were neither lenticular opacities nor cataract formation. CONCLUSION Diode laser photocoagulation with the laser indirect ophthalmoscope can be used safely in eyes with tunica vasculosa lentis. At the laser energy levels used in our study, no transient lens opacities or cataract formation occurred. However, the results of this study are limited by a relatively small number of patients and a relatively short follow-up.

Trans-scleral diode laser photocoagulation in proliferative sickle cell retinopathy

OBJECTIVE To demonstrate the feasibility of trans-scleral diode laser photocoagulation for the treatment of proliferative sickle cell retinopathy. DESIGN Interventional case report. INTERVENTION Trans-scleral diode laser scatter photocoagulation was applied to both eyes of a 30-year-old man with hemoglobin SC disease. MAIN OUTCOME MEASURES Regression of retinal vascular proliferation and of dye leakage on fluorescein angiography. RESULTS After coagulation, vascular proliferation receded completely. Vitreous bleeding was absorbed. There were no side effects during follow-up (22 months). CONCLUSION Trans-scleral diode laser photocoagulation proved to be an effective and safe treatment in a case of proliferative sickle cell retinopathy with vitreous bleeding.