Laser in situ keratomileusis after automated lamellar keratoplasty and penetrating keratoplasty

We present three patients who had laser in situ keratomileusis (LASIK) after corneal surgery as follow: 15 months after automated lamellar keratoplasty (ALK) for hyperopia, 6 months after ALK for hyperopia, and 2 years after penetrating keratoplasty (PKP). Although the first case was uneventful, intraoperative complications arose in the second case because the connection of the ALK-related flap to its stromal bed was insufficient. In the third case, the refractive error caused by PKP was corrected as shown by corneal topography and visual acuity measurement. In conclusion, LASIK after PKP can be considered a precise and safe procedure if 2 to 3 years pass between the procedures. An interval of 6 months between ALK and LASIK was too short, whereas 15 months after ALK for hyperopia, LASIK was performed without problems and delivered a good result.     

Pellucid marginal corneal degeneration 12 years after penetrating keratoplasty for keratoconus

Historically the divisions between the mental health and substance abuse fields have been so deep that attempts to provide coordinated treatment across service sectors for people with dual diagnoses of psychiatric disorder and substance use disorder have failed. The authors describe a program in Maine designed to develop collaboratives, or communities of providers, who work together to offer coordinated mental health and substance abuse treatment and support. Surveys of provider agencies in one collaborative conducted one year and two years after the collaborative was established showed an increase in interagency referrals, joint assessments of clients, and jointly sponsored training and client services.     

A surgical technique for posterior lamellar keratoplasty

PURPOSE: To design a surgical technique for transplantation of posterior corneal tissue, while leaving the recipient anterior cornea intact. METHODS: In human cadaver eyes, and in a cat and monkey model, recipient eyes had an 8.0-mm limbal incision made with a diamond blade set to 50% of central pachymetry. A stromal pocket was created across the cornea, and a 6.0-mm diameter posterior lamellar disc was excised. A donor posterior disc was implanted into the recipient opening, and the limbal incision was sutured. The procedure was evaluated with keratometry, biomicroscopy, endothelial (supra)vital staining, and light microscopy. RESULTS: In human cadaver eyes, post-operative astigmatism averaged 1.2 D (SD, +/- 0.6 D). Posterior transplants showed an intact endothelial cell layer with 1.0% (SD, +/- 1.2%) of cell death. In the animals, six (75%) eyes had clear transplants 2 weeks after surgery; one of these eyes later developed an allograft rejection. Two (25%) eyes showed corneal decompensation, because of inverted implantation of the donor disc. Microscopy showed minimal scarring at the donor-to-host interface and a normal wound-healing response at the posterior stromal wound edges. CONCLUSION: In experimental models, posterior lamellar keratoplasty can be performed through a limbal incision and a mid-stromal pocket. The procedure may be a potential alternative in the surgical management of corneal endothelial disorders.     

Automated lamellar keratoplasty for the correction of hyperopia

Hyperopic automated lamellar keratoplasty (H-ALK) is a refractive procedure that corrects low to moderate hyperopia of up to +5.00 diopters (D). In this retrospective series, we examined the efficacy, predictability, and safety of H-ALK in 85 eyes in 49 patients. Follow-up was from 4 to 34 weeks (mean 18 weeks). Eyes were divided into three subsets: those in which we attempted an emmetropic result (n = 45), those in which we attempted to reduce, but not eliminate, hyperopia greater than 5.00 D (n = 23), and those in which we attempted a monovision result of -1.50 D (n = 17). In the eyes in which we attempted emmetropia, 76% achieved uncorrected visual acuity of 20/40 or better and 78.6% were within a range of -1.00 to +0.87 D. In those in which we attempted monovision, 47% achieved a spherical equivalent result between -2.50 and -1.00 D because of a tendency toward undercorrection. In those in which we attempted to reduce hyperopia, there was a mean correction of 4.33 D (standard deviation 1.36 D), with a range of 2.12 to 6.75 D. The most significant complication was a reduction in best corrected visual acuity of one to three lines in 11 of 85 eyes; this was transient in six eyes. These preliminary results compare favorably with those of other procedures to correct hyperopia.     

Peripheral radial incisions to treat inferior contact lens edge lift after penetrating keratoplasty for keratoconus

A patient with marked corneal astigmatism and inferior contact edge lift after penetrating keratoplasty for keratoconus had corneal relaxing incisions (CRIs) on the donor button and radial incisions on the host cornea. Results were evaluated by computerized videokeratography and by refitting the contact lens. Two pairs of CRIs decreased astigmatism from 11.00 to 4.25 diopters but did not alleviate the contact lens edge lift, which was caused by excessive steepness in the keratoconic host cornea. After 6 radial incisions were made to flatten the inferior host cornea, the peripheral cornea flattened and the patient was successfully refitted with a contact lens.     

Readaptation time after photo stress. Readaptation time as a function of oxygen concentration

Optokinetic nystagmus (OKN) is used to study the eye's ReAdaptation Time (RAT) after a brief exposure to a light flash. The effects on RAT of breathing different concentrations of O2 are examined. Significant changes in RAT have been registered, showing that inhalation of 100% O2 as compared with room air, results in a shortened RAT (i.e. improvement), while inhalation of 9% O2 leads to an increased RAT (i.e. impairment). The physiology of RAT and the possible mechanisms behind the changes caused by different O2 concentrations are discussed. The findings of this group are compared with those of other studies.     

Retrephination keratoplasty for high astigmatism after penetrating keratoplasty

PURPOSE: We report preliminary results of a new procedure for correcting high astigmatism after penetrating keratoplasty. METHODS: The procedure entails full-thickness trephination along the original donor-recipient junction with careful suturing in a combined interrupted and running fashion. Four eyes of four patients with severe astigmatism and myopia after penetrating keratoplasty underwent the procedure. RESULTS: High preoperative cylinder ranging from 4.50 to 16.00 D (mean 9.00 D) was reduced to 0.50 to 3.50 D (mean 1.90 D) at the last examination (between 3 to 6 months). Spherical equivalent myopia ranging from -2.00 to -10.25 D (mean -4.90 D) was essentially unchanged at plano to -9.00 D (-4.70 D) at the last examination. Overall, there was a mean refractive cylinder reduction of 7.10 D (79%). CONCLUSION: Retrephination after penetrating keratoplasty appears to be an acceptable alternative for correcting high astigmatism, and had only a small effect on the level of myopia.     

Depth of lamellar keratoplasty with the guided trephine system for transplantation of full-thickness donor sections

BACKGROUND: Despite the fact that deep lamellar keratoplasty (DLKP) is less invasive than to penetrating keratoplasty (PKP), this procedure is rarely performed. We therefore investigated whether or not the DLKP technique we employed can achieve stable improvement of visual acuity. MATERIALS AND METHODS: Thirty-three eyes underwent TLKP for treatment of superficial corneal pathology. The donor tissue transplanted was suitable for PKP. The donor lenticule was obtained on the artificial chamber of the guided trephine system (GTS). The recipient cornea was trephined with the same trephine to a depth of 680 microns. Manual dissection was performed with a bevel-up blade. The donor lenticule with the endothelium peeled off was then sutured in with a 10 x 0 nylon double-running antitorque suture. Cortisone-antibiotic eye drops were administered postoperatively. RESULTS: Throughout the series no complications occurred. The mean best corrected visual acuity (BSCVA) over glasses was 0.29 (+/- 0.21) preoperatively, 0.1 (+/- 0.11) at 1 week, 0.33 (+/- 0.14) at 1 month, 0.5 (+/- 0.13) at 6 months, 0.61 (+/- 0.16) at 1 year and 0.63 (+/- 0.15) at 2 years. Clinically, we observed two subpopulations. In the first group of 87% of the cases, mean BSCVA was 0.67 (+/- 0.07) at 6 months. The remaining cases (BSCVA < or = 0.25 at 6 months) achieved a mean BSCVA of only 0.2 (+/- 0.04) at 1 year. Mean corneal astigmatism measured 2.93 D (+/- 1.62) preoperatively, 2.69 D (+/- 1.18) at 1 month, 2.09 D (+/- 1.07) at 1 year, and 2.22 D (+/- 1.11) at 2 years. We did not observe any graft rejection. CONCLUSION: The technique reported for DLKP provides excellent matching of donor lenticule and recipient bed. Separation of donor and recipient stroma prevents interface healing. DLKP appears to be a safe procedure for the surgical treatment of superficial corneal pathology and may offer a clinically applicable alternative to PKP.     

Memory for prose as a function of learning strategy and inspection time.

Describes 2 experiments each employing 60 undergraduates as Ss. Exp I showed that (a) providing specific instructions (goal directed or directed forgetting) about how to process a passage induced readers to study most of the material at a slower pace, and (b) when Ss were told to place special emphasis on some of the material, they spent more time on the material that was not emphasized as well as on the material that was emphasized, but without a similar increase in learning. Exp II showed that the increase in inspection time for the emphasized material was necessary for increased learning of these sentences to occur. It is concluded that both the type of processing and the duration of processing influence retention in goal-directed learning tasks. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory colour effects as a function of viewing time.

Instructed 60 Ss to judge the color of 2 objects, an apple, and a circle, relative to the colors of 5 samples. The apple was judged significantly redder than the circle, indicating a memory color effect. There was also an indication that this effect was stronger when the test object was viewed for 300 msec. than when it was seen for either more or less time. These results fit a modified version of J. S. Bruner's model of perceptual processing. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cyclocryotherapy for refractory glaucoma after penetrating keratoplasty

Twenty-eight patients (28 eyes) with secondary glaucoma following penetrating keratoplasty and failed to respond to anti-glaucoma drugs and routine filtering procedures were performed with cyclocryotherapy by nitrogen monoxide. All patients were followed up for more than one year. The results showed intraocular pressure was well controlled in 89% of the eyes, graft remained clear in 85%, and visual functions are preserved in 82% of the patients. Our study suggests that precisely controlled temperature, time, and extent of cryotherapy, and post-operative anti-rejection agents be the key factor to success. Over-treatment, which may lead to atrophy of the eye, must be avoided. It should not be given up flowing under-treatment in the initial procedure.     

Variations in sleep mentation as a function of time of night

Mentation reports collected from sleep onset, Stage 2 and REM Stage awakenings, in the first part and in the second part of the night were analyzed both with systematic psycholinguistic and global measures. Results confirm the relationship between activation and the length of sleep mentation report shown by Antrobus. Length of the report increases with sleep time, but time does not modulate qualitative inter-stage differences. By partialling out the length of the report, many inter-stage differences disappeared; however significant differences remain in the global measure of bizarreness and in the psycholinguistic measure of visual imagery. These results cannot be explained entirely by differences in attention and memory and point to more basic differences in mental activity.     

Primary creep behavior of Ti-48Al-2W as a function of stress and lamellar morphology

The fully lamellar microstructure of powder metallurgy Ti-48Al-2W after cooling from the α region to 1280 °C, followed by air cooling and aging at 950 °C for up to 96 hours, is presented. Aging times as short as 5 hours result in acicular-shaped precipitates of W-rich β ₀ along lamellar interfaces, with the β ₀ size increasing with aging time. The β ₀ precipitates nucleate and grow in the α ₂ lamellae. Concurrently, with the formation of β ₀, the α ₂ decomposes into discontinuous lamellae. Aging to precipitate β ₀ along lamellar interfaces increases the 760 °C tensile strength (with a slight reduction of ductility) and reduces the instantaneous creep strain, since β ₀ precipitates at lamellar interfaces hinder interface dislocation mobility. The deformed microstructures from interrupted creep tests at 140 to 276 MPa at 760 °C indicate that the precipitation of β ₀ along interfaces substantially reduces the primary creep strain, primarily due to the influence of β ₀ on interface dislocation emission and motion. These results are discussed in terms of the influence of lamellar morphology on the instantaneous creep strain and primary creep transient, and the possible creep mechanisms are highlighted. This article is based on a presentation made in the symposium entitled “Fundamentals of Structural Intermetallics,” presented at the 2002 TMS Annual Meeting, February 21–27, 2002, in Seattle, Washington, under the auspices of the ASM and TMS Joint Committee of Mechanical Behavior of Materials.     

Psychotherapy process as a function of the time segment sampled.

Employed a content analysis of individual psychotherapy tapes of 25 female undergraduates to determine the relative frequencies of certain response measures during the 1st, 2nd, 3rd, 4th, and 5th 10-min segments of the therapeutic hr. An attempt was made to test the assumption made by many investigators that the occurrence of a given phenomenon is evenly distributed over the course of therapy. Results indicate that such an assumption is grossly inaccurate given variables appeared consistently more frequently in certain segments of the hr. than they did in others. It is suggested that examining the variable where it occurs most often will increase the power of future investigations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in infants'' cries as a function of time in a cry bout

Endoluminal ultrasound of the obstructed ureteropelvic junction (UPJ) provides accurate anatomic information not available through other studies. Endoluminal ultrasonography in the evaluation of the obstructed UPJ can be extremely valuable and its use can be expected to expand with increasing experience with the techniques. The anatomy demonstrated through the fine resolution of this technique may ultimately provide the key to the selection of optimal therapy for the obstructed UPJ.     

Visual target location as a function of number and kind of competing signals.

Using 20 college students, the influence of hue and shape on ability of operators to correctly describe location of objects, reflected on radar picture tubes, was studied. Variables included number of target signals, values of hue-shape combinations, number of signals, and the distribution of this competition between the hue and shape dimensions. The number of targets had by far the greatest effect on task time. Hue rather than shape is the critical factor. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rubber band ligation of hemorrhoids: relapse as a function of time

Rubber band ligation is a well established treatment of internal second-degree hemorrhoids. Up to now, the long-term results (> 5 years) of this method have not been assessed. The aim of this study was to determine the long-term success rate of rubber band ligation in patients with a first episode of second-degree hemorrhoids not responding to medical treatment (local cream with laxative). A total of 92 patients who were treated between 1979 and 1997 for second-degree hemorrhoids responded to a questionnaire. The need for complementary conservative (sclerotherapy, cryotherapy or rubber band ligation) or surgical treatment was considered indicative of relapse. The collected data were analyzed according to the Kaplan-Meier method. The average follow-up time was 5.6 years. There were 21 patients who suffered a relapse. The probability of successful treatment was 0.77 (range: 0.67-0.88) after 5 years and 0.68 (range: 0.5-0.86) after 10.6 years. We conclude that rubber band ligation represent an efficient long-term treatment for second-degree hemorrhoids. Approximately two thirds of the patients are cured after 5 years and more than a half after 10 years.     

Iatrogenic keratectasia after LASIK in a case of forme fruste keratoconus

We report an iatrogenic corneal ectasia that developed after laser in situ keratomileusis (LASIK) in a case of forme fruste keratoconus. One month postoperatively, corneal topography revealed a central steep area that showed rapid progression. Visual acuity in the eye decreased from 20/20 to 20/80. Corneas with forme fruste keratoconus may have altered biomechanical properties compared with normal corneas. Forme fruste keratoconus may be a contraindication for LASIK.     

Life-span differences in memory integration as a function of processing time.

K. Pezdek (see record 1981-03016-001) reported life-span differences in integration of semantically related pictures and sentences in memory; 6th-grade and high school Ss spontaneously integrated information across modalities, but 3rd graders and adults over 65 did not integrate this information. The present study extends these findings and tests the hypothesis that the 8-sec presentation rate in the previous study was not sufficient to allow the young children and older adults to perform integration processes in memory. Although 3rd graders and older adults (63–78 yrs) did not integrate pictures and sentences that were presented individually at an 8-sec rate, when the presentation rate was increased to 15 sec per item, cross-modality integration resulted. This result is interpreted to mean that the slower presentation rate was necessary for these Ss to actively rehearse different items together, and that this rehearsal strategy is necessary for integration of information in memory. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)