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Objective To test prospectively a new biologic rationale for an advanced hyper oxygen-transmissible lens (HOTL) providing prospects for safer daily (DW) or extended (EW) contact lens wear. Design Prospective, randomized, double-masked, single-center, 13-month clinical trial. Participants One hundred sixty-eight patients completed the DW study (1 month): control lens (n = 70); HOTL (n = 98). One hundred thirty-six patients finished 1 year of EW: controls (n = 56), HOTL (n = 25, 6 nights; n=55, 30 nights). Testing Irrigation chamber to collect corneal surface cells, confocal microscopy, tear collection at baseline, 2, and 4, weeks of DW, and 24 hours, 1, 3, 6, 9, and 12 months of EW. Main outcome measures (1) Pseudomonas aeruginosa (PA) binding to exfoliated corneal surface cells; (2) central epithelial thickness (CET); (3) superficial cell area (SCA); (4) epithelial surface cell exfoliation (DESQ); and (5) tear lactate dehydrogenase (LDH). Results Daily wear with control lens increased PA binding from 5.90 ± 2.60 to 7.81 ± 3.04 bacteria per cell ( P P P = 0.0017), but not after 1 month of subsequent EW ( P = 0.533). One to 3 months of EW with control lens showed significantly higher PA binding than HOTL wear ( P P Conclusions Hyper oxygen-transmissible lens wear (DW or EW) produced significantly decreased PA binding compared with control lens wear, with no significant difference in wearing schedule (6 nights vs. 30 nights); additionally, there was a remarkable and unexpected adaptive recovery in the first 6 months of all soft lens wear, with a return to baseline PA binding levels and partial recovery for the other outcomes except SCA at 1 year. These results suggest that HOTL use should result in a decrease in the incidence of and risk(s) for lens-related microbial keratitis and that further epidemiologic studies should consider time in adapted EW in future risk and incidence analyses.

Objective To determine effects of lens type and oxygen transmissibility on human corneal epithelium during extended wear (EW). Design Prospective, randomized, double-masked, single-center, parallel treatment groups, 1-year clinical trial. Participants One hundred seventy-eight patients completed the study: (1) high-O 2 soft lens (6-night [N] EW) (n = 27); (2) hyper-O 2 soft lens (6N-EW, n=33) or (30N-EW, n=66); and (3) hyper-O 2 rigid gas-permeable lens (RGP) (30N-EW, n=52). Intervention Irrigation chamber to collect exfoliated corneal surface cells, confocal microscopy, and tear collection at baseline, 1, 3, 6, 9, 12 months of EW. Main outcome measures (1) Pseudomonas aeruginosa (PA) binding to exfoliated corneal surface cells; (2) central epithelial thickness; (3) superficial epithelial cell area; (4) epithelial surface cell exfoliation; and (5) tear lactate dehydrogenase. Results Quantitative evidence demonstrated increased binding of PA to human exfoliated corneal epithelial cells during the first 3 months of soft lens EW; the control high-O 2 test lens showed significantly higher bacterial binding ( P P 2 soft lens for all outcome measures. Importantly, hyper-O 2 RGP lens wear did not show significantly increased PA binding during 1 year. Conclusions This study establishes three important new findings: (1) hyper-O 2 soft lens EW produces significantly less PA binding than the lower O 2 soft lens with no significant difference in PA binding with 6N versus 30N EW of the hyper-O 2 soft lens; (2) there is a remarkable adaptive recovery after 6 months with all soft lens wear with gradual return to prelens PA binding levels and partial recovery of other outcome measures for all test lenses EW except surface cell size; (3) 30N EW of the hyper-O 2 RGP lens produced no significant increases in PA binding over 1 year. Taken together, these results suggest that introduction of new hyper-O 2 transmissible lens materials into clinical use may offer safer EW, and future epidemiologic studies of ulcerative infectious keratitis should consider both lens type and time in lens EW in any incidence/risk analysis.

To determine the effects of lens type and oxygen transmissibility on human corneal epithelium during daily lens wear (DW).Prospective, randomized, double-masked, single-center, parallel treatment groups clinical trial.Two hundred forty-six patients fitted with: (1) high oxygen-transmissible soft lenses (n = 36), (2) hyper oxygen-transmissible soft lenses (n = 135), and (3) hyper oxygen-transmissible rigid gas-permeable (RGP) lenses (n = 75).Irrigation chamber to collect exfoliated epithelial surface cells, confocal microscopy, and tear collection at baseline, 2 weeks, and 4 weeks of DW.(1) Pseudomonas aeruginosa (PA) binding to exfoliated corneal epithelial surface cells, (2) central epithelial thickness, (3) superficial epithelial cell area, (4) epithelial surface cell exfoliation, and (5) tear lactate dehydrogenase (LDH).Four weeks of DW with the high oxygen-transmissible soft lens significantly increased PA binding from baseline 6.55 +/- 3.01 to 8.75 +/- 3.05 bacteria per epithelial cell (P0.01). By contrast, hyper oxygen-transmissible soft lens wear increased binding significantly less (6.13 +/- 2.45 to 7.62 +/- 3.06; P0.01), whereas hyper oxygen-transmissible RGP lens wear demonstrated no significant changes (5.91 +/- 2.40 to 6.13 +/- 2.17; P = 0.533). No significant change in central epithelial thickness was found after 4 weeks of DW in either soft lens; however, the epithelial thickness decreased by 9.8% (P0.001) with RGP lens wear. Epithelial cell surface area increased 3.3% and 4.1% with the high and hyper oxygen-transmissible soft lenses, respectively, and 10.5% with the hyper oxygen-transmissible RGP lens (P0.001). Epithelial desquamation significantly decreased in all groups (P0.001). Tear LDH levels increased for all test lenses (P0.001).Increased PA binding induced by wear of a conventional soft lens material is significantly greater than that induced by the new hyper oxygen-transmissible soft silicone hydrogel lens during DW. However, both soft materials showed significant increases in PA binding as compared with baseline controls. By contrast, hyper oxygen-transmissible RGP lens DW did not increase PA binding significantly. Taken together, these findings suggest for the first time both an oxygen effect as well as a difference between soft and rigid lens types on PA binding in DW.

Purpose To determine differences of corneal wound healing and haze after photorefractive keratectomy (PRK) using either mechanical epithelial debridement or laser-scrape epithelial removal in human subjects. Design A 6-month randomized, masked, prospective, paired-eye clinical study. Participants Twenty eyes in 10 myopic patients treated between March 1999 and May 1999. Intervention Photorefractive keratectomy treatments with two different epithelial removal techniques. Continuous z-scan of confocal image, termed confocal microscopy through focusing (CMTF), was performed before surgery and at 3 weeks, 6 weeks, 3 months, and 6 months after surgery. Main outcomes measures Epithelial and stromal thickness measurement, achieved stromal ablation depth, and objective assessment of corneal light-backscattering (corneal haze) were obtained from digital image analysis of the CMTF scans. Manifest refraction was also measured. Student's paired t test or two-way repeated-measures analysis of variance after rank transformation were performed to evaluate statistical differences between groups. Results Comparison of the mean posttreatment spherical equivalent between the two techniques showed no statistically significant difference. In preoperative corneas, mean epithelial thickness was 50.08 ± 3.70 μm in the mechanical debridement group and 50.49 ± 4.01 μm in laser-scrape group (not significant). For both groups, the epithelium was significantly thinner at 3 weeks, but returned to preoperative values by 6 months, with no difference between groups. Planned stromal ablation depth by PRK was 59.38 ± 11.48 μm (39–73 μm; n=8) in the mechanical group and 57.75 ± 7.21 μm (48–70 μm; n=8) in the laser-scrape group. Achieved stromal ablation depth was not significantly different between the two groups. Most importantly, in both groups CMTF-measured corneal haze increased significantly after surgery, peaked at 3 months, and then decreased at 6 months, with no significant difference between groups. (Power = 0.96). Conclusions There is no significant difference in the corneal wound healing response between mechanical epithelial debridement versus laser-scrape technique in human myopic eyes undergoing PRK.

Purpose To evaluate the mechanism(s) producing refractive instability and corneal haze development after photorefractive keratectomy (PRK). Design Prospective, nonrandomized, comparative case series, self-controlled. Participants Seventeen eyes of 17 patients with low- to moderate-grade myopia (−2.88 to −9.13 diopters [D]) were included. Methods Surgical intervention was a standardized, 6-mm diameter PRK procedure using the Meditec MEL 60 excimer laser (Aesculap-Meditec, Heroldsberg, Germany). The photoablation center was evaluated before surgery and at 1, 3, 6, 9, and 12 months after PRK using rapid, continuous z-scans of confocal images, termed confocal microscopy through focusing (CMTF). Main outcome measures Simultaneous epithelial and stromal thickness analysis and objective assessment of corneal light backscattering were obtained from digital image analysis of the CMTF scans. Corneal reinnervation and anterior stromal keratocyte density and wound healing morphologic features were evaluated on high resolution, in vivo confocal images. Manifest refraction was measured and corneal clarity was graded by slit-lamp biomicroscopy. Results Epithelial thickness averaged 45 ± 10 μm at 1 month, 50 ± 8 μm at 3 months, and 52 ± 6 μm at 12 months after PRK, as compared with 51 ± 4 μm before surgery, demonstrating complete restoration of the preoperative thickness without compensatory hyperplasia. Interestingly, epithelial rethickening had no significant correlation with refractive regression. By contrast, stromal regrowth (from 1–12 months) averaged 6 ± 12 μm (range, 27 μm thinning–22 μm rethickening) and correlated closely ( r = 0.84, P r = 0.63, P cellular-based reflections, as opposed to extracellular matrix deposition, are the major origin of increased corneal light scattering after PRK. Conclusions Taken together, these data indicate that keratocyte-mediated regrowth of the photoablated stroma appears to be the main cause of myopic regression in humans treated with a 6-mm diameter PRK, whereas hyperopic shifts appear to be a direct consequence of stromal thinning. By contrast, the corneal epithelium appeared to restore its preoperative thickness without contributing significantly to the refractive changes after PRK. Finally, this study also provides strong evidence that the development of haze after PRK is directly associated with increased cellular reflectivity from high numbers of wound healing keratocytes.

In this issue of Ophthalmology, 2 articles examine the anatomic features that largely determine the corneal tissue response in the performance of 2 evolving corneal transplantation procedures: Descemet’s membrane endothelial keratoplasty (DMEK), by Schlotzer-Schrehardt et al, and deep anterior lamellar keratoplasty (DALK), by Dua et al. These articles have similar themes, exploring the structural biology that may determine the success or failure of these 2 different surgical procedures, both of which operate on the very posterior limits of the corneal stroma and posterior limiting lamina (Descemet’s membrane). Importantly, both articles intersect the often neglected but increasingly important fields of structural biology and biomechanics, in that DMEK and DALK apply strain to different corneal layers to induce delamination of Descemet’s membrane from the posterior stroma.

To test prospectively a new biologic rationale for an advanced hyper oxygen-transmissible lens (HOTL) providing prospects for safer daily (DW) or extended (EW) contact lens wear.Prospective, randomized, double-masked, single-center, 13-month clinical trial.One hundred sixty-eight patients completed the DW study (1 month): control lens (n = 70); HOTL (n = 98). One hundred thirty-six patients finished 1 year of EW: controls (n = 56), HOTL (n = 25, 6 nights; n = 55, 30 nights).Irrigation chamber to collect corneal surface cells, confocal microscopy, tear collection at baseline, 2, and 4, weeks of DW, and 24 hours, 1, 3, 6, 9, and 12 months of EW.(1) Pseudomonas aeruginosa (PA) binding to exfoliated corneal surface cells; (2) central epithelial thickness (CET); (3) superficial cell area (SCA); (4) epithelial surface cell exfoliation (DESQ); and (5) tear lactate dehydrogenase (LDH).Daily wear with control lens increased PA binding from 5.90 +/- 2.60 to 7.81 +/- 3.04 bacteria per cell (P0.01); HOTL wear increased PA binding significantly less (5.31 +/- 1.87-5.98 +/- 2.26; P0.01). Daily wear produced no significant changes in CET or SCA. Significant decreases in DESQ were seen with both lenses with no significant intergroup differences. Tear LDH increased significantly in DW with HOTL wear versus control (P = 0.0017), but not after 1 month of subsequent EW (P = 0.533). One to 3 months of EW with control lens showed significantly higher PA binding than HOTL wear (P0.01); binding adaptively decreased thereafter, returning to baseline at 9 to 12 months. Lens EW produced significantly enlarged SCA, thinning of CET (except 6-night HOTL wear), and decreased DESQ (P0.01). Some adaptive recovery was seen with CET and DESQ, but not SCA; importantly, the data indicated no significant difference between 6- or 30-night EW for all outcomes.Hyper oxygen-transmissible lens wear (DW or EW) produced significantly decreased PA binding compared with control lens wear, with no significant difference in wearing schedule (6 nights vs. 30 nights); additionally, there was a remarkable and unexpected adaptive recovery in the first 6 months of all soft lens wear, with a return to baseline PA binding levels and partial recovery for the other outcomes except SCA at 1 year. These results suggest that HOTL use should result in a decrease in the incidence of and risk(s) for lens-related microbial keratitis and that further epidemiologic studies should consider time in adapted EW in future risk and incidence analyses.

To analyze tissue matrix metalloproteinase (MMP) expression in three patients who developed postoperative corneal melts after treatment with topical diclofenac sodium 0.1% (Falcon; Fort Worth, TX) ophthalmic solution.Retrospective noncomparative interventional case series with tissue analysis.Three patients were examined in this study. We report two patients from the same center with acute corneal melts after uncomplicated photorefractive keratectomy (PRK). Prior to these cases, 1500 patients were treated at the Zale Lipshy University Laser Center for Vision with no adverse effects. All 1500 patients were treated with the same postoperative regimen of ciprofloxacin, rimexolone, and suprofen ([Profenal, (CIBA, Duluth, GA]). The next 27 cases were treated postoperatively with ciprofloxacin and rimexolone. However, diclofenac sodium 0.1% was used instead of Profenal. A third case was also discussed. This melt occurred at another center in a postoperative cataract patient who developed cystoid macular edema after cataract extraction with intraocular lens placement. He was initially treated with diclofenac sodium 0.1% (Ciba Vision, Duluth, GA) then with diclofenac sodium 0.1%. He subsequently developed a corneal perforation requiring penetrating keratoplasty. All tissue specimens were examined by light microscopy. Microbiologic cultures and stains were also performed. Immunolocalization and in situ hybridization were performed on all keratoplasty specimens to detect expression and localization of MMPs. All patients had a complete diagnostic evaluation for systemic autoimmune diseases.Postoperatively, all patients developed corneal perforations requiring surgical intervention while being treated with diclofenac sodium 0.1%. Microbiologic cultures and special stains were negative for microorganisms. Induced expression of specific tissue degrading enzymes of the matrix metalloproteinase family was demonstrated within corneal epithelial cells, stromal keratocytes, and at the level of Descemet's membrane. The uniform distribution pattern of expression was not consistent with the localization expected of a repair response, suggesting the involvement of some outside agent.Whereas MMP expression is a normal component of repair, excessive or inappropriate MMP activity is associated with corneal keratolysis. Our study provides preliminary evidence that topical application of diclofenac sodium 0.1% may be associated with aberrant MMP expression in the cornea.

To determine effects of lens type and oxygen transmissibility on human corneal epithelium during extended wear (EW).Prospective, randomized, double-masked, single-center, parallel treatment groups, 1-year clinical trial.One hundred seventy-eight patients completed the study: (1) high-O(2) soft lens (6-night [N] EW) (n = 27); (2) hyper-O(2) soft lens (6N-EW, n = 33) or (30N-EW, n = 66); and (3) hyper-O(2) rigid gas-permeable lens (RGP) (30N-EW, n = 52).Irrigation chamber to collect exfoliated corneal surface cells, confocal microscopy, and tear collection at baseline, 1, 3, 6, 9, 12 months of EW.(1) Pseudomonas aeruginosa (PA) binding to exfoliated corneal surface cells; (2) central epithelial thickness; (3) superficial epithelial cell area; (4) epithelial surface cell exfoliation; and (5) tear lactate dehydrogenase.Quantitative evidence demonstrated increased binding of PA to human exfoliated corneal epithelial cells during the first 3 months of soft lens EW; the control high-O(2) test lens showed significantly higher bacterial binding (P0.05). Binding activity gradually decreased thereafter and returned to baseline after 9 and 12 months. The corneal epithelium demonstrated enlargement of surface cell size, thinning of central epithelium, and a significant decrease in surface cell shedding (P0.05). Remarkably, there was subsequent partial adaptive recovery in cell shedding and epithelial thickness but not surface cell size. There was no significant difference between 6N and 30N continuous wear of the hyper-O(2) soft lens for all outcome measures. Importantly, hyper-O(2) RGP lens wear did not show significantly increased PA binding during 1 year.This study establishes three important new findings: (1) hyper-O(2) soft lens EW produces significantly less PA binding than the lower O(2) soft lens with no significant difference in PA binding with 6N versus 30N EW of the hyper-O(2) soft lens; (2) there is a remarkable adaptive recovery after 6 months with all soft lens wear with gradual return to prelens PA binding levels and partial recovery of other outcome measures for all test lenses EW except surface cell size; (3) 30N EW of the hyper-O(2) RGP lens produced no significant increases in PA binding over 1 year. Taken together, these results suggest that introduction of new hyper-O(2) transmissible lens materials into clinical use may offer safer EW, and future epidemiologic studies of ulcerative infectious keratitis should consider both lens type and time in lens EW in any incidence/risk analysis.

The authors establish, for the first time, observer-independent quantification of stromal thinning, epithelial thickness, and corneal haze after excimer laser photorefractive keratectomy (PRK) using a unique, new form of in vivo confocal microscopy.Rapid, continuous z-scans of high-resolution confocal images, termed confocal microscopy through focusing (CMTF), were performed in the central corneal area of 17 patients before and 1 month after PRK for low- to moderate-grade myopia (-2.88-9.13 diopters [D]). Corneal, epithelial, and stromal thickness measurements and an objective haze estimate were obtained from each CMTF scan by digital image analysis.Epithelial thickness averaged 51 +/- 4 microns before and 45 +/- 10 microns 1 month post-PRK (P0.005), whereas stromal thinning ranged from 20 to 154 microns, representing a direct estimate of the actual photoablation depth. Corneal thickness averaged 560 +/- 36 microns before PRK and 462 +/- 52 microns at 1 month. The change in corneal thickness correlated closely with the change in spherical equivalent refraction (r = 0.94, P0.0001); linear regression analysis revealed a value of 14.3 microns corneal thinning per diopter of correction. A significant correlation was found between the objective CMTF haze estimate and a clinical haze grading obtained by slit-lamp examination (r = 0.73, P0.001).Confocal microscopy through focusing is a new, powerful in vivo tool that enables quantitative, unbiased evaluation of PRK procedures over time by providing epithelial and stromal thickness analysis, photoablation depth assessment, and unbiased haze measurement. The method is uniquely valuable in the pre- and postoperative assessment of PRK patients and for determining the optimal treatment strategy, especially in assessing refractive and visual outcomes in individual cases.

Purpose: To assess adverse effects of contact lens-induced hypoxia on the rabbit cornea in vivo and determine the relation between binding of Pseudomonas aeruginosa and oxygen transmissibility for rigid and hydrogel lenses. Methods: Six rigid lenses with Dk/L total values between 0 and 97 X 10 -9 (cm/second) (ml O 2 /ml mmHg) and four hydrogel lenses (Dk/L total 9, 20, 39, 51) were tested. All lenses had 14.0-mm diameters and a thickness (parallel) of 0.12 or 0.15 mm. Tear lactate dehydrogenase activity and tandem scanning confocal microscopy determinations were performed after the lens was worn for 24 hours. Binding of P. aeruginosa then was separately determined by the colony-forming unit method. Scanning electron microscopy was used to confirm in vivo tandem scanning confocal microscopy findings. Results: Lens oxygen transmissibility determines binding of P. aeruginosa to the cornea after the lens is worn for 24 hours; epithelial damage produced by lenses of lower Dk/L total appears to be the dominant biologic factor for P. aeruginosa binding and not lens rigidity. Conclusions: These results suggest that the risk of P. aeruginosa keratitis developing with overnight wear will be enhanced significantly for contact lenses with Dk/L total values less than 50 X 10 -9 (cm/second) (ml O 2 /ml mmHg) (human equivalent oxygen percentage ≤ 15%), and this risk will increase with further decreases in oxygen transmissibility. Because no hydrogel lenses approved by the Food and Drug Administration are available with oxygen transmission at this level, patients should be made aware of the increased risk of infectious keratitis associated with the overnight wear of current extended wear hydrogel lenses. Results of this study also demonstrate that quantitative clinical tandem scanning confocal microscopy imaging and tear lactate dehydrogenase activity measurements can provide prospective, noninvasive methods for assessing the ongoing interaction between contact lens and cornea in vivo.

Background: The purpose of this article is to introduce the practicing ophthalmologist to the optical principles and images produced by a tandem scanning confocal microscope (recently approved by the Food and Drug Administration for general clinical use). The tandem scanning confocal microscope allows real-time viewing of structures in the living cornea at the cellular level in four dimensions (x, y, z, and time). Methods: Nine patients (2 males, 7 females), ranging in age from 7 to 52 years, were examined. Images were recorded on super VHS videotape, digitized and processed on a computer workstation, and photographed for presentation. Results: Two-dimensional (x, y) 400 X 400-µm images (9-µm z-axis thickness) are presented for normal corneal structures and for the clinical conditions of herpetic keratitis, wound healing after myopic excimer ablation, Acanthamoeba infection, corneal dystrophies (granular, Reis-Buckler), contact lens abrasion, and the irido-corneal endothelial syndrome. Conclusion: Clinical confocal microscopy has the unique potential of providing noninvasive assessment of corneal injury and disease at the cellular level that is not available currently from other technologies.

Radial keratotomy was performed on six stumptail monkey eyes (Macaca speciosa) and 22 owl monkey eyes (Aotus trivirgotus). Changes in keratometry, specular microscopy, and tonometry have been studied postoperatively for three to six months. Sixteen radial incisions in stumptail monkey eyes resulted in a significant mean corneal flattening of 2.75 diopters (P less than 0.005). This effect was stable with a mean 2.50 diopters flattening remaining six months after surgery. Sixteen radial incisions in ten owl monkey eyes resulted in a much greater short-term effect, with a mean 10.50 diopters of flattening present at two weeks postoperatively. This flattening deteriorated over the observation period, and no significant effect was noted three months after surgery. A comparison of 8 vs 16 incisions on owl monkey eyes demonstrated that these two procedures are equally effective in initially flattening the cornea. Complications and side effects encountered included perforations, irregular astigmatism, corneal neovascularization, transitory increase in pachometry, and decrease in central corneal endothelial cell density in isolated cases.

Keratomileusis was investigated in five stumptail monkey eyes ( Macaca speciosa ). An arbitrary flattening of six diopters was selected and programmed in the computer for each eye. The actual flattening achieved two weeks after surgery ranged from −4.00 D to − 6.00 diopters (D). One to 5 diopters of the initial effect was lost during the six-month observation period. Histopathology of two eyes demonstrated attenuation and/or loss of Bowman's membrane with overlying epithelial defects.

Eight-incision radial keratotomy was performed on a series of cadaver eyes using ultrasonic pachymetry and both metal and diamond blades. There were no statistically significant differences in mean corneal flattening (approximately 9.5 diopters) obtained with either the diamond or metal blades. Short diamond knife incisions produced less flattening that was statistically significant (5.8 diopters). Histologic analysis of incision depth revealed similar results with both the diamond (84%) and metal (86%) blades.

We present ultrastructural findings in two cases, one of keratophakia (9 months postoperatively) and one of keratomileusis (1 year, 7 months postoperatively), which best demonstrate the pathologic changes we observed in six cases of cryorefractive surgery. In addition, we studied a rabbit model of keratophakia which appears to exhibit similar features to that of human keratophakia. In the keratomileusis cases, there were marked abnormalities, including deposition of redundant basal lamina, loss of Bowman's membrane and deposition of a 6 nm fibrillar material in areas devoid of Bowman's membrane. In keratophakia lenticule we noted the absence of keratocyte regeneration, abnormal deposition of long-spacing collagen, and the presence of necrotic cellular debris. In experimental keratophakia, little to no evidence of keratocyte regeneration was evident 4 months after surgery. Keratophakia lenticules implanted into actively regenerating corneas induced by freeze injury exhibit only a slight increase in the number of keratocytes migrating into the donor tissue, suggesting that implants lack a primary factor necessary for keratocyte regeneration. Immunofluorescent localization of fibronectin and fibrinogen demonstrated absence of these factors in normal host stroma, implanted lenticules and freeze injured corneal stroma. Actively migrating fibroblasts, however, did react positively for fibronectin, suggesting that these cells synthesize and secrete fibronectin during regeneration. These results do not support a role for soluble fibronectin or fibrinogen in keratocyte repopulation.

A 29-year-old woman had unilateral essential iris atrophy, corneal endothelial changes, and absolute glaucoma. The enucleated eye was examined by routine light microscopy. Separate portions of unfixed fresh frozen cornea were sectioned and reacted with monoclonal antibodies against keratins, vimentin, and inflammatory cell markers. Stains for filamentous actin (f-actin) were performed using the 7-nitro-benz-2-oxa-1,3-diazolylphallacidin (NBD phallacidin) probe. In addition, portions of cornea and iris were examined by scanning and transmission electron microscopy. Immunocytochemical stains with anti-keratin antibodies showed reactivity only in the corneal epithelium of the patient and normal control. Immunoreactivity with anti-vimentin antibodies was observed in corneal endothelium and keratocytes of the patient and control, but was negative in the epithelium. Staining for f-actin appeared more pronounced in the corneal endothelium of the patient. Scanning electron microscopy of the corneal endothelium showed irregularity in cell size and shape and filopodial processes characteristic of migrating cells. Transmission electron microscopy disclosed abnormalities of Descemet's membrane and endothelium with a posterior collagenous layer. The corneal endothelium displayed normal junctional complexes without desmosomal junctions or increased microvillus projections. Increased 10-nm cytoplasmic filaments were noted consistent with the expression of vimentin. Occasional chronic inflammatory cells perturbed the corneal endothelium and were detected within the endothelial layer. Alterations in the endothelium and Descemet's membrane suggest the acquired nature of this disease.

Meibomian gland transillumination biomicroscopy and infrared photography were performed on 18 patients with clinically evident meibomian gland dysfunction (MGD) and dermatologic rosacea, 22 patients having MGD without evidence of dermatologic rosacea, and 15 unaffected individuals who served as controls. All patients having clinical signs of MGD demonstrated morphologic abnormalities of their meibomian glands by transilluminated biomicroscopy. Patients without dermatologic rosacea were noted to have varying degrees of gland distortion. Moreover, infrared photography documented a loss of the normal grape-like clusters of dark spots that represent the gland, suggesting a loss of glandular acini. Patients with dermatologic rosacea had more severe alterations, including marked distortion and loss of normal gland anatomy. There were no such abnormalities in clinically unaffected individuals. These data demonstrate that transilluminated biomicroscopy and infrared photography have the ability to identify a spectrum of morphologic alterations of the meibomian glands in MGD patients. The authors suggest that these techniques could be used to classify clinical MGD based upon the presence or absence of identifiable meibomian gland abnormalities.

Radial keratotomy in fresh human cadaver eyes produced corneal flattening varying from 6 to 11 diopters (D). There was no significant difference in the effectiveness of the incisions to the incisions to the limbus compared to incisions through the limbus. Eighty to ninety percent of the flattening effect was obtained after the first eight incisions. The preoperative keratotomy reading was not helpful in predicting the final result. Histopathology of the incised corneas revealed considerable variation in incision depth and demonstrates the difficulty in achieving deep incisions safely.