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Biomedical subjects

I Schipper

Publications and source records attributed to I Schipper.

At least 37 records · Page 2Linked to original sources
PubMed1997

Autorefraction/autokeratometry and subjective refraction in untreated and photorefractive keratectomy-treated eyes.

OBJECTIVE: To examine the relative accuracy of autorefraction and autokeratometry (autorefraction/autokeratometry) and subjective refraction in untreated and photorefractive keratectomy (PRK)-treated eyes. DESIGN: Results of autorefraction/autokeratometry obtained by means of 2 contemporary devices (Nidek ARK 2000 and Canon Rk-3) were compared with those of subjective refraction in 48 untreated eyes and in 78 eyes treated with (PRK). RESULTS: A trend toward greater differences between subjective and objective methods in PRK-treated eyes was observed. Both autorefraction devices showed similarly higher differences from subjective readings in PRK-treated eyes with regard to sphere (P < .001) and cylinder (P = .02), but not axis (P =.4). For autokeratometry, the mean difference from manual readings was highly significant when all K readings were considered together, but not so for the individual differences in keratometric astigmatism (Canon RK-3 and Nidek ARK 2000 vs manual results: P =.03 and P =.93, respectively) and keratometric axis (Canon RK-3 and Nidek ARK 2000 vs manual results: P =.88 and P =.19, respectively). CONCLUSIONS: Refractive and keratometric readings obtained with the automated devices tested in this study varied more from those obtained with subjective methods when the eyes examined had been treated with PRK. Corneal topographical changes inherent in the wound-healing process may influence objective measurement with automated devices.

Adult↗
PubMed1997

Photoastigmatic refractive keratectomy for primary treatment and revision of myopic astigmatism.

PURPOSE: To evaluate the results in 43 eyes treated with a rotating mask for myopic astigmatism and followed for up to 1 year. SETTING: Lucerne Eye Clinic, Cantonal Hospital, Lucerne, Switzerland. METHODS: Thirty-two patients (42 eyes) were selected to have photoastigmatic refractive keratectomy (PARK). In 33% (14 eyes), this treatment was the second or third ablation. The Aesculap Meditec MEL 60 excimer laser was operated in toe scanning slit mode, and a rotating mask was used. To evaluate cylindrical shaping, vector analysis was performed. RESULTS: One year after PARK, mean uncorrected visual acuity in all patients (26 eyes) improved from 20/160 preoperatively to 20/40. Surgically induced astigmatism in 20 of 26 eyes (77%) was within +/- 1.00 diopter (D) of the targeted induced astigmatism. At 1 year, 81% of patients who had primary excimer laser treatment for myopic astigmatism equivalent to -10.00 D or less were within +/- 1.00 D of target refraction compared with 44% of re-treated eyes. CONCLUSION: The result of PARK in eyes with low to moderate degrees of myopic astigmatism was satisfactory. However, in eyes with extensive scarring and wound healing activity after the first ablation, re-treatment was less predictable.

Adult↗
PubMed1997

Mitomycin C reduces scar formation after excimer laser (193 nm) photorefractive keratectomy in rabbits.

Sixteen eyes of eight rabbits were randomised to either mitomycin C or Balanced Salt Solution (BSS) application after photorefractive keratectomy (PRK). Regular examinations of wound healing and haze were performed with the slit lamp. The animals were killed between 1 and 26 weeks after treatment, and the corneas examined by light and electron microscopy. While the grade of haze showed no relevant differences between the two groups, scar tissue was found histologically in the mitomycin group in only 1 of 8 corneas compared with 5 of 8 in the BSS group. A marked reduction in keratocytes in all mitomycin-treated corneas and a normal density of keratocytes in the BSS group was observed. Mitomycin reduced the number of keratocytes in the treated corneas, leading to less scar formation but not to a reduction in haze. Since no morphological correlate has been found, haze remains unexplained in the mitomycin-treated corneas.

Animals↗
PubMed1997

[Confocal microscopy of the corneal after photorefractive keratectomy with the excimer laser].

BACKGROUND: In photorefractive keratectomy (PRK) procedures, a variable superficial central corneal scar formation ("haze") can be observed following removal of corneal stromal tissue. Today, a near to normal slit lamp finding is observed one year postoperatively in most patients. We employed the slit scanning confocal microscope to study the corneal morphology years after PRK. METHODS: We selected 5 patients, who had been subjected to unilateral photorefractive surgery 1-3 years earlier and who had no corneal haze upon slit lamp examination. As controls we investigated the non-treated corneas of these patients, 5 healthy controls and 5 contact lens wearers. The confocal microscopic investigation was performed with 25x, 40x and 50x water immersion objectives. The video signal was synconized with the slit scan and stored on S-VHS video tape. By reviewing the videos in the single frame mode, all corneal layers could be qualitatively evaluated. RESULTS: Some minor abnormalities were observed in the epithelium of all PRK-treated eyes. In the epithelial basal cell layer some round structures of about the size of a cell with high reflectivity were observed. These changes were only occasionally found in contact lens wearers, but not in non-treated or normal control eyes. Bowman's layer was absent in the PRK treated eyes, instead, a fine layer of collagen tissue of increased reflectivity was found. The subepithelial corneal nerve plexus was normal in all non-treated eyes, whereas in the PRK-treated corneas nerve shape and branching pattern were changed to quite an extent. In the anterior stroma the keratocyte nucleus patterns indicated an increased cell density and irregular spacing, whereas a normal keratocyte pattern was found in the deeper stromal layers. A significant finding was the observation of rod and needle shaped highly reflective structures, which were limited to the area of the excimer laser keratectomy with a predominance in the anterior stroma. These longitudinal structures themselves consisted of linearly arranged highly reflective granules, which sometimes also were found as isolated dots within keratocyte processes. In long term contact lens wearers a comparable granule type, however with a singular and scattered arrangement, was variably found in all corneal regions and layers. In normal controls none of these findings were present. In contact lens wearers and PRK patients with a contact lens history, the corneal endothelium showed some degree of polymegathisms but no other specific findings. DISCUSSION: Up to now, refractive surgery with the excimer laser has been reported to elicit no other stromal changes but a mild fibroblast activation with subsequent scar tissue formation. In clinically clear corneas after PRK, we have described a new type of stromal deposit observed 1-3 years after surgery. As acute wound healing responses might have been expected to have passed at this point, this highly reflective stromal deposit can be assumed to consist of linear keratocyte processes filled with some highly reflective (degenerative?) matter as well as a corresponding extracellular stromal deposit arranged parallel to the stromal collagen bundles. Possibly, these stromal deposits represent the result of an inflammatory or degenerative stromal response resulting in the formation of stromal lipofuscein deposits. Visual acuity was not impaired in the patients investigated in this study. As these stromal deposits appear to be persisting years after surgery and possibly are irreversible in nature, a long term effect on the corneal physiology and function should carefully be monitored.

Adult↗
PubMed1997

Glare sensitivity and visual acuity after excimer laser photorefractive keratectomy for myopia.

BACKGROUND: Following excimer laser photorefractive keratectomy (PRK), an increase in glare sensitivity and a reduction in contrast sensitivity can occur owing to changes in the cornea (structure and topography). In this study, an attempt was made to quantify and document objectively a change in those subjective perceptual factors. METHODS: Snellen visual acuity and disability glare were measured with the Berkeley glare test preoperatively as well as 1, 3, 6, 9, and 12 months postoperatively, after excimer laser photorefractive keratectomy (PRK) on 32 myopic patients (46 eyes). During the postoperative progress checks, haze was graded and contrast sensitivity was measured with the Vistech chart. All the data were statistically analysed by multiple regression. RESULTS: One year after PRK, a reduction in visual acuity (VA) measured with the low acuity contrast chart (10%) with and without glare could still be found, despite the fact that acuity measurements with a high contrast Snellen chart showed the same VA 6 months postoperatively as well as before the treatment. The lowest VA could be measured 1 month postoperatively; thereafter, the acuity increased despite the increase in haze that occurred during the first 3 months. CONCLUSION: Disability glare and a reduction in contrast sensitivity could be observed in most patients after PRK treatment with the Meditec laser system with its scanning slit. The future will show if new technology and a broader flattening area of 6 to 7 mm can minimise these postoperative complications.

Adult↗
PubMed1997

Low levels of follicle-stimulating hormone receptor-activation inhibitors in serum and follicular fluid from normal controls and anovulatory patients with or without polycystic ovary syndrome.

In patients with normogonadotropic anovulation, either with or without polycystic ovary syndrome (PCOS), factors interfering with FSH action may be involved in arrested follicle development. The aim of this study is to assess whether factors inhibiting FSH receptor activation are elevated in serum or follicular fluid from anovulatory patients, as compared with regularly cycling women. For this purpose, a Chinese hamster ovary cell line, stably transfected with the human FSH receptor, has been applied. FSH-stimulated cAMP secretion in culture medium was measured in the presence of serum or follicular fluid. Chinese hamster ovary cells were stimulated with a fixed concentration of FSH (3 or 6 mIU/mL) to mimic FSH levels in serum or follicular fluid. Samples were added in concentrations ranging from 3-90% vol/vol to approach protein concentrations occurring in serum or follicular fluid. In the presence of 10% vol/vol serum from regularly cycling women (n = 8), FSH-stimulated cAMP production was inhibited to 42 +/- 2% (mean +/- SEM of 2 experiments, each performed in duplicate) of cAMP production in the absence of serum, whereas a similar cAMP level (up to 38 +/- 4% of the serum-free level) was observed at higher concentrations of serum (30-90% vol/vol). The inhibition of FSH-stimulated cAMP production in the presence of serum samples from normogonadotropic anovulatory patients, without (n = 13) or with (n = 16) PCOS, was similar to controls. Follicular fluid samples (n = 57) obtained during the follicular phase in 25 regularly cycling women and follicular fluid samples (n = 25) from 5 PCOS patients were tested in a slightly modified assay system. In the presence of 10 or 30% (vol/vol) follicular fluid, FSH-stimulated cAMP levels were decreased to 68 +/- 2% and 55 +/- 2% (mean +/- SEM of a single experiment in triplicate) of the cAMP levels in the absence of follicular fluid, respectively. There was no correlation between the degree of cAMP inhibition and follicle size, steroid content (androstenedione or estradiol concentrations), or menstrual cycle phase. Furthermore, no differences in inhibition were found, comparing PCOS follicles with size- and steroid content-matched follicles obtained during the normal follicular phase. It is concluded that inhibition of FSH receptor activation by proteins present in serum or follicular fluid is constant (60 and 40%, respectively) and independent from the developmental stage of the follicle, either during the normal follicular phase or in patients with normogonadotropic anovulation. Inhibition of FSH receptor activation may be of limited significance for normal and arrested follicle development.

Adult↗
PubMed1997

Interaction between silicone oil and silicone intraocular lenses: an in vitro study.

The objective of this study was to examine the interaction between silicone oil and silicone intraocular lenses (IOLs) in vitro. Six types of silicone IOLs were placed in silicone oil (1000 or 5000 centistokes) for 1 minute, 7 days, and 420 days. Slit-lamp examination, target photographs, and opacity measurements were performed. Optical measurements were repeated in a balanced salt solution after removal from the oil. The IOL surface was examined through scanning electron microscopy, and surface irregularities underwent x-ray spectroscopy. No changes were observed while the IOLs were stored in silicone oil, but in the balanced salt solution, the IOLs were observed to have a layer of silicone oil droplets that reduced the optical quality. Scanning electron microscopy showed that oil-coated foreign body particles were simulating IOL surface defects. After ultrasonic cleaning with ethanol, the oil layer was broken, and no damage to the IOL surface could be detected. The length of exposure to silicone oil, the type of oil, and the type of IOL were found to have no bearing on the interaction between silicone oil and silicone IOLs. Although no surface damage is incurred by silicone IOLs from silicone oil, the reduction in optical quality and fundus view due to remnant oil droplets seems to indicate that complex cases requiring silicone oil injection may contraindicate IOLs made of silicone.

Adhesiveness↗
PubMed1996

Reproducibility of the data determined by scanning laser polarimetry.

BACKGROUND: Scanning laser polarimetry is a tool for measuring the retinal nerve fiber layer: both its cross-sectional surface (polarimetric data analysis) and its thickness (mean sector values). METHODS: Two observers examined 56 normal volunteers twice by means of scanning laser polarimetry (Nerve Fiber Analyzer type 1, software version 1.6). Measurements of the retinal nerve fiber layer were carried out in four equal sectors of a circle around the optic nerve head. The measured values of the sectors and the calculated ratios among them were used for statistical analysis. Interobserver and intraobserver reproducibility were analyzed following a balanced random three-way cross classification with interactions. Interobserver reproducibility was defined as the part of variance not influenced by the observers. Intraobserver reproducibility was defined as the part of variance not influenced by the time. RESULTS: For repeated measurements of the retinal nerve fiber layer, better intraobserver than interobserver reproducibility was found (0.57-0.79 vs 0.11-0.44). The interobserver reproducibility was improved (0.24-0.65) in comparison to the intraobserver reproducibility (0.32-0.68) by calculating the ratios of the measured values. CONCLUSION: The instrument is clinically useful only if used by the same observer. If measurements are performed by different observers the ratios of the measurements must be used. Further development in the apparatus is needed to improve interobserver reproducibility.

Adolescent↗
PubMed1996

Drug-induced ciliary body oedema: a new theory.

Drug-induced oedema of the ciliary body is rare, and occurs predominantly following exposure to sulphonamides. In a 31-year-old patient in her 37th week of pregnancy, we observed reversible myopia of -4.75 dioptres following the ingestion of chlorthalidone. In a second case report we describe, in a 61-year-old patient suffering from aspirin-sensitive asthma, recurrent ciliary body oedema with a marked spastic component which was triggered by the medications acetazolamide, dipivefrine and pilocarpine. We explain oedema of the ciliary body on the basis of the eicosanoids. We believe that the oedema is caused mainly by prostaglandins and that leucotrienes are predominantly responsible for the spastic component. We postulate a drug-induced elevation in eicosanoid concentrations, as well as certain interrelationships between ciliary body oedema and aspirin-sensitive asthma.

Acetazolamide↗
PubMed1996

Normal human follicle development: an evaluation of correlations with oestradiol, androstenedione and progesterone levels in individual follicles.

OBJECTIVE: The mechanism of dominant follicle selection remains obscure. We have investigated the association between follicle diameter and follicular steroid levels in individual human ovarian follicles throughout the menstrual cycle. DESIGN: Fluid from ovarian follicles (n = 326) was obtained in vivo during surgery from 55 regularly cycling women with proven fertility. Follicles were divided into dominant (diameter >9 mm, n = 45) and non-dominant (diameter < or = 9 mm, n = 281) based on ultrasound measurements. MEASUREMENTS: Fluid was assayed for oestradiol (E2), androstenedione (AD), and progesterone (P). RESULTS: Median P and E2 levels were significantly lower (P < 0.0001) and AD levels significantly higher (P = 0.03) in non-dominant as compared to dominant follicles. In non-dominant follicles AD (r = 0.14, P = 0.02), but not P and E2, levels were correlated to follicular diameter, and significant changes in steroid concentrations across the menstrual cycle were absent. In dominant follicles, diameter was positively correlated with P and E2 (P < 0.001) levels, and inversely correlated with AD concentrations (P = 0.01). CONCLUSIONS: Results indicate that (1) intrafollicular oestradiol concentrations rise only in follicles exceeding 9 mm in diameter and correlate with the diameter of these dominant follicles, suggesting that significant increase in aromatase enzyme activity occurs only in the dominant follicle (2) a cycle-independent accumulation of androstenedione with size occurs in non-dominant follicles, and (3) progesterone production occurs in the largest dominant follicles only, suggesting a limited, if any, role for progesterone during follicle development.

Adult↗
PubMed1996

Circulating immunoreactive and bioactive follicle stimulating hormone concentrations in anovulatory infertile women and during gonadotrophin induction of ovulation using a decremental dose regimen.

Our purpose was to determine whether decreased follicle stimulating hormone (FSH) activity, either systemic or at the follicular level, is involved in impaired follicle growth associated with normogonadotrophic anovulation. To differentiate between the possible levels of disturbance, bioactive (BIO-FSH; using the in-vitro rat granulosa cell aromatase bioassay) and immunoreactive (IRMA-FSH) FSH serum concentrations of three groups of subjects were compared: (i) 172 normogonadotrophic anovulatory infertile women during baseline conditions, (ii) 22 clomiphene-resistant polycystic ovary syndrome patients undergoing ovulation induction by exogenous gonadotrophins using a decremental dose regimen, and (iii) nine regularly cycling controls. BIO-FSH [13.2 (range 0.8-29.5) IU/l] and IRMA-FSH [4.4 (range 1.2-9.3) IU/l] concentrations in anovulatory women during baseline conditions were significantly lower than maximum concentrations reached during the follicular phase in controls [18.7 (13.2-23.4) and 6.4 (5.7-10.0) IU/l respectively], but were not significantly different from initial concentrations in controls [10.4 (7.2-19.6) and 4.8 (2.8-8.2) IU/l respectively]. Moreover, concentrations of IRMA-FSH and BIO-FSH were negatively correlated (r = -0.25, P = 0.01, and r = -0.24, P = 0.02 respectively) with the interval between last vaginal bleeding and blood sampling. Maximum concentrations of IRMA-FSH [7.6 (3.9-10.9) IU/l] during ovulation induction by gonadotrophins were not significantly different from maximum [6.4 (5.7-10.0) IU/l] concentrations in controls, whereas maximum BIO-FSH concentrations [13.5 (8.7-17.4) versus 18.7 (13.2-23.4) IU/l] were significantly lower. Our findings suggest that (i) circulating FSH does not reach concentrations that are sufficient to induce normal follicle development in anovulatory women during baseline conditions, and (ii) the FSH threshold for ovarian stimulation of this patient group is not different from normal.

Adult↗
PubMed1996

Application of a CHO cell line transfected with the human FSH receptor for the measurement of specific FSH receptor activation inhibitors in human serum.

Effects of FSH on ovarian follicular development can be modulated by factors present in serum or by locally produced factors in follicular fluid. Some of these factors may act directly on the FSH receptor. A Chinese hamster ovary cell line (CHO-F3B4) stably transfected with the human FSH receptor has been used to measure the effects of these modulators on FSH-stimulated adenylate cyclase activity. After incubation of CHO-F3B4 cells with human recombinant FSH (recFSH) for 4 h, cAMP levels were elevated 100-230 times above basal levels (ED50 24.9 mU/ml recFSH). cAMP production was inhibited after the addition of increasing amounts (up to 90% of the incubation volume) of hypogonadotrophic human serum (HS) at a fixed stimulatory dose of 30 mU/ml recFSH. At 10% HS the cAMP response was diminished to approximately 40-60% of the original value, whereas at a concentration of 90% HS the cAMP values were diminished to 30%. Effects of serum components on cell viability could be excluded, since forskolin- and cholera-toxin-stimulated cAMP production were not affected by preincubation of the cells in the presence of HS. The FSH-stimulated oestradiol production in rat Sertoli cells, which has been used frequently for in vitro bioassays of FSH, was almost completely inhibited by the addition of human serum, suggesting that serum has more pronounced effects on events downstream of receptor activation. Various specific FSH binding inhibitors have been demonstrated by radioreceptor assays to be present in serum. In order to assess whether such FSH receptor binding inhibitors would also inhibit receptor activation, the specific conditions used in the radioreceptor assays (buffers of low ionic strength) were also used to measure the effects of serum on FSH receptor activation. Under these conditions (a low-salt buffer, corrected for low osmolarity with 200 mM sucrose), CHO-F3B4 cells responded to FSH stimulation in a similar way to that observed in normal buffers. When CHO-F3B4 cells were incubated in this low-salt buffer with a fixed low dose of FSH (3 mU/ml), the addition of 3-90% (v/v) dialysed HS inhibited the FSH-stimulated cAMP accumulation to a similar extent to that in standard conditions. The observed inhibition of adenylate cyclase activation by the low-molecular-mass fraction (< 10 kDa) of HS could be attributed to the presence of salts in this fraction, since the addition of PBS in similar concentrations displayed an equal degree of inhibition. It is concluded that the inhibitory effects of serum on FSH-stimulated cAMP production in CHO-F3B4 cells are small, compared with the inhibition of aromatase induction in rat Sertoli cells. The strong inhibition of aromatase in rat Sertoli cells may result from the effects of serum acting on the FSH receptors as well as on other pathways not related to the FSH receptor. Therefore, measurement of aromatase in Sertoli cells is not suitable for the detection of inhibitors of FSH receptor activation. The CHO-F3B4 cells are useful for the measurement of whether inhibition of FSH receptor activation occurs in serum or follicular fluid from patients with disturbed follicle development.

Adenylyl Cyclases↗
PubMed1996

Disability glare after excimer laser photorefractive keratectomy for myopia.

BACKGROUND: A change of corneal topography and haze after excimer laser photorefractive keratectomy (PRK) can reduce contrast sensitivity and cause glare. Both glare and contrast sensitivity can be examined in a reproducible manner with one instrument. METHODS: We have used the Berkeley Glare Test to examine 46 eyes of 32 patients before and 1, 3, 6, 9, and 12 months after excimer laser PRK for moderate to high myopia. Multiple regression analysis was used for statistical analysis. RESULTS: High contrast visual acuity showed a statistically significant deterioration during the first 6 months after PRK (p = 0.01); 1 year after treatment visual acuity returned to almost pretreatment levels (p = 0.2). High- and low contrast visual acuity under glare deteriorated significantly 3 months after PRK and had only risen slightly 1 year later (p < or = 0.0065). A similar development could be observed for the low contrast visual acuity without glare. CONCLUSION: Although high contrast visual acuity recovers by 1 year after PRK, low contrast visual acuity and glare deteriorate significantly and do not recover, even after 1 year.

Adult↗
PubMed1996

Successful phototherapeutic keratectomy for recurrent erosions in bullous keratopathy.

BACKGROUND: The treatment of patients with recurrent erosions due to bullous keratopathy is disappointing in cases when penetrating keratoplasty cannot be performed. A trial has been made to prevent recurrent erosions through the smoothing of the cornea with the excimer laser. METHODS: Excimer laser phototherapeutic keratectomy (PTK) was performed after removal of the epithelium. RESULTS: Sixteen patients (17 eyes) with recurrent erosions due to bullous keratopathy were treated. The mean follow-up period was 17.2 months (range: 3 to 32 months). All patients responded well to the treatment; their pain subsided after a few weeks. In four cases, a second treatment was necessary because areas with loose epithelium remained, which resulted in recurrent erosions. No complications have been seen so far. CONCLUSION: Excimer laser PTK is an effective, easy to perform treatment of bullous keratopathy.

Adult↗
PubMed1995

[Are we measuring the right intraocular pressure after excimer laser photorefractive laser keratoplasty in myopia?].

BACKGROUND: It is possible that the traditional method to determine the intraocular pressure after excimer-laser PRK is inaccurate. Measuring the pressure in the temporal part of the cornea might give the true values. METHODS: Intraocular pressure was measured with a Goldmann Applanation Tonometer and with the Tonopen, before and after PRK for myopia in the central and in the temporal parts of the cornea. The paired student t-test was used for statistical analysis. RESULTS: The results of central and temporal measurements before treatment were identical with both instruments. After PRK, central values were 2 to 3 mm Hg lower than temporal values when measured with a Goldmann Tonometer, and about 2 mm lower when measured with the Tonopen. The differences were highly significant (p < 0.0001 and p = 0.004 respectively). CONCLUSIONS: The intraocular pressure measured in the usual manner after excimer-laser PRK is lower than the temporally measured pressure. These differences could be caused by absence of the Bowman's membrane, thinning of the cornea and/or change of its topography.

Cornea↗
PubMed1995

Phototherapeutic keratectomy for bullous keratopathy.

AIMS: This study was designed to investigate the therapeutic potential of excimer laser for recurrent painful erosions in patients not suited to treatment with penetrating keratoplasty. METHODS: Phototherapeutic keratectomy (PTK) with the excimer laser was performed prospectively on a series of 13 eyes of 12 patients with recurrent corneal erosions in connection with bullous keratopathy of varied aetiology. The main complaint of the patients before the treatment was frequent attacks of pain. The patients selected either refused corneal grafting or could not for a variety of reasons expect to profit visually from an operation. The treatment was performed with the MEL 60 Aesculap Meditec excimer laser using either a spot mode (five cases), a scanning mode (three cases), or a combination of both (five cases). RESULTS: All patients responded well to the treatment, and the pain subsided after a couple of weeks. In five cases (38.5%) a second treatment was necessary because of persistent pain, which was, however, much less than before the initial treatment. In four of these five patients small corneal bullae persisted. The visual performance of the seven patients with visual acuity better than 20/200 ameliorated in two cases and remained unchanged in four cases. One patient lost two Snellen lines after the laser treatment for terminal glaucoma. The mean follow up was 14.1 months (range 1-28 months). No complications were seen so far. CONCLUSION: It was concluded that PTK is a very promising and effective outpatient treatment for patients with bullous keratopathy. This therapeutic approach is not thought to have been described before.

Adult↗