Cloning and sequence analysis of human and bovine corneal antigen (CO-Ag) cDNA: identification of host-parasite protein calgranulin C

PURPOSE

The primary structure of a cornea-associated antigen (CO-Ag) has been identified and has been implicated in the pathogenesis of Mooren's ulcer. The study designs were to isolate full-length clones encoding CO-Ag from a bovine and a human corneal cDNA library so that complete sequence analyses might further define the possible role of this protein in Mooren's ulcer.

METHODS

DNA fragments of bovine and human CO-Ag were generated using unique oligonucleotide primers and reverse transcription polymerase chain reaction. These fragments were used as probes to obtain cDNA clones from a bovine and a human corneal cDNA libraries. The clones with the longest cDNA inserts were selected for sequence analyses. Human cDNA fragment was digested with Stu I and Hind III and cloned into a expression vector, pPROEXHT, at the same restriction enzyme sites. The plasmid was transformed into E. coli cells. Correct cloning and the full-length sequence of human CO-Ag were determined by sequencing the insert cDNA.

RESULTS

The bovine cDNA insert sequence was 273 nucleotides in length for the entire mRNA coding region, 212 nucleotides in the 5' untranslated region, 83 nucleotides in the 3' untranslated region and a poly(A) tail. The DNA base sequence of this clone also contained a standard initiation codon, termination codon, and the polyadenylation signal. This cDNA predicts a protein which contains 91 amino acids with a molecular weight of 10,584 daltons. Plasmid expression vector, pPROEXHT-CO-Ag, was constructed that direct the synthesis of human CO-Ag in E. coli as fusion protein. Human CO-Ag fusion protein was purified to 90% pure with a yield of 17.2 mg per liter of the bacterial cell lysate. The nucleotide sequence of the CO-Ag cDNA insert was completely identical to human neutrophil calgranulin C. The deduced amino acid sequence was completely identical to a Ca(2+)-binding protein isolated on the surface of filarial nematodes.

CONCLUSIONS

The isolation and analysis of cDNA clones containing the complete coding sequence of bovine and human CO-Ag proteins is reported. The proteins identified by deduced amino acid sequences demonstrate 100% sequence homology with human and bovine calgranulin C. Immune recognition of calgranulin C to a filarial nematode may lead to a hyperactive autoimmune response to CO-Ag in the cornea leading to a Mooren's ulcer.

Intrastromal epithelial accretion follows deep excimer annular keratectomy

The purpose of this study was to evaluate corneal reepithelialization and wound healing following annular excimer keratectomy. Two sets of experiments were performed on 35 rabbit eyes. In the first set of experiments, experiment I, deep Fresnel excimer keratectomy was performed, with a 6-mm outer and 3-mm inner diameter. Animals were sacrificed at 1, 5, 12, and 16 weeks, and corneas were examined by light and electron microscopy. In experiment II, the central epithelium was left intact, and superficial and deep mid-peripheral excimer annular keratectomies were performed measuring 6 mm in outer and 3 mm in inner diameter. Animals were sacrificed at 1 week, and corneas were examined by light microscopy. Following deep Fresnel excimer keratectomy (experiment I), corneas showed stromal edema in the central 3-mm zone. Intrastromal islands of epithelial cells with PAS positive basement membrane-like structures were seen histologically at 1 week. Electron microscopy showed loss of stromal collagen in areas adjacent to epithelial islands; in areas distant from the epithelial islands, the stromal collagen appeared normal. The overlying central stroma sloughed after 5 weeks. Anterior stromal scarring was observed. In experiment II (mid-peripheral annular keratectomy), intrastromal epithelial accretion was present in corneas with deep annular keratectomy but not in superficial annular keratectomy. Intrastromal epithelial accretion follows deep excimer annular keratectomy and is associated with adjacent stromal degradation.

The association of postoperative subjective visual function with acuity, glare, and contrast sensitivity in patients with early cataract

BACKGROUND

It has been shown in our previous studies that early cataracts affect vision in ways that can be measured by objective means and that this objective impairment in visual acuity, glare, and contrast sensitivity can be successfully reversed by cataract surgery.

OBJECTIVE

To evaluate the association of subjective visual function with objective measures of acuity, glare, and contrast sensitivity in patients who were symptomatic from early cataract.

METHODS

We administered a task-oriented questionnaire prior to and 4 months after cataract surgery to patients who were symptomatic from early cataract (median preoperative ETDRS [Early Treatment Diabetic Retinopathy Study] visual acuity of 20/40 [range, 20/20 to 20/80]); ETDRS visual acuity, disability glare, and contrast sensitivity were also measured at those times.

RESULTS

Uncomplicated cataract surgery resulted in resolution or improvement of subjective symptoms for the great majority of subjects, and in a few subjects new symptoms developed or current symptoms worsened. We found a positive association between postoperative improvement in subjective visual function (as measured by the questionnaire) and postoperative improvement in objective visual function (as measured by visual acuity and contrast sensitivity). We also found that the greater the degree of preoperative impairment in objective visual function (as measured by visual acuity and contrast sensitivity), the greater the postoperative improvement in subjective visual function (as measured by the questionnaire). No such association was found for our disability glare test.

CONCLUSIONS

Cataract surgery for symptomatic individuals with mild impairment in visual acuity does relieve visual symptoms, and preoperative measurement of contrast sensitivity can help determine who with early cataract is most likely to report subjective improvement in vision.

Excimer Laser Calibration System

BACKGROUND

Excimer laser photoablation for refractive and therapeutic keratectomies has been demonstrated to be feasible and practicable. However, corneal laser ablations are not without problems, including the delivery and maintenance of a homogeneous beam. We have developed an excimer laser calibration system capable of characterizing a laser ablation profile.

METHODS

Beam homogeneity is determined by the analysis of a polymethylmethacrylate (PMMA)-based thin-film using video capture and image processing. The ablation profile is presented as a color-coded map. Interpolation of excimer calibration system analysis provides a three-dimensional representation of elevation profiles that correlates with two-dimensional scanning profilometry. Excimer calibration analysis was performed before treating a monkey undergoing phototherapeutic keratectomy and two human subjects undergoing myopic spherocylindrical photorefractive keratectomy. Excimer calibration analysis was performed before and after laser refurbishing.

RESULTS

Laser ablation profiles in PMMA are resolved by the excimer calibration system to .006 microns/pulse. Correlations with ablative patterns in a monkey cornea were demonstrated with preoperative and postoperative keratometry using corneal topography, and two human subjects using video-keratography. Excimer calibration analysis predicted a central-steep-island ablative pattern with the VISX Twenty/Twenty laser, which was confirmed by corneal topography immediately postoperatively and at 1 week after reepithelialization in the monkey. Predicted central steep islands in the two human subjects were confirmed by video-keratography at 1 week and at 1 month. Subsequent technical refurbishing of the laser resulted in a beam with an overall increased ablation rate measured as microns/pulse with a donut ablation profile. A patient treated after repair of the laser electrodes demonstrated no central island.

CONCLUSIONS

This excimer laser calibration system can precisely detect laser-beam ablation profiles. The calibration system correctly predicted central islands after excimer photoablation in a treated monkey cornea and in two treated human subjects. Detection of excimer-laser-beam ablation profiles may be useful for precise calibration of excimer lasers before human photorefractive and therapeutic surgery.

Objective measurement of corneal light scattering after excimer laser keratectomy

PURPOSE

To obtain objective measurements of corneal light scattering after excimer laser keratectomy, and to evaluate the relation of light scattering to clinical haze grading and visual acuity.

METHODS

The authors measured best-corrected visual acuity, subjective clinical haze grade, and corneal light-scattering index in patients undergoing photorefractive keratectomy (PRK) (n=26), and phototherapeutic keratectomy (n=8), preoperatively and postoperatively at 1,3,6,9, and 12 months or later. Corneal light scattering was correlated with visual acuity and clinical haze grade.

RESULTS

Corneal light scattering increased after PRK and was reduced after phototherapeutic keratectomy. Corneal light scattering index showed a stronger positive correlation with logMAR visual acuity (r=0.57) than clinical haze grading (r=0.34). Corneal light-scattering index (P<0.05 at 1 and 3 months) and clinical haze grading (P<0.05 at 6, 9, and 12 months) were significantly higher in eyes undergoing PRK with ablation depths of more than 80 microns.

CONCLUSIONS

Excimer laser surgery affects corneal light scattering. Ablations with depths greater than 80 microns produce significantly higher levels of haze than those less than 80 microns. Objective measurement of corneal light scattering may be useful in monitoring the outcome of excimer keratectomy.

Phacoemulsification after retinal detachment surgery

PURPOSE

Previous studies have documented a 3% to 15.5% risk of retinal redetachment in eyes with prior scleral buckling procedures that later undergo intracapsular or extracapsular cataract extraction. The authors reviewed the records of patients with a history of retinal detachment (RD) surgery and subsequent phacoemulsification to assess the risk of retinal redetachment and the visual outcomes.

METHODS

Forty-seven eyes of 44 patients with a history of scleral buckling surgery who subsequently underwent phacoemulsification were identified. Features found before, during, and after surgery were reviewed.

RESULTS

No retinal redetachments occurred on a mean follow-up of 2.3 years. Eyes with RD repair were more myopic than fellow eyes (P=<0.001), had longer axial lengths (P=0.001), had steeper keratometry readings (P=0.03), and had larger differences in K readings between principal meridians (P=0.01). Postoperative visual acuity was 20/40 or better in 72.3% of eyes and 20/80 or worse in 6.4% of eyes. Preexisting macular pathology was responsible for poor outcomes.

CONCLUSION

The risk of redetachment after phacoemulsification in eyes with previous RD surgery is low. Despite retinal and cataract surgery, these eyes can achieve useful vision.

The Castroviejo square graft

The histopathologic features of three keratoplasty specimens from three cases involving square graft procedures performed by Dr. Castroviejo are reported. Light and electron microscopy were performed. In two of the cases, repeat keratoplasties were performed because of recurrent corneal dystrophies. In the third case, a repeat keratoplasty was performed because of graft failure.

Corneal complications of intraocular surgery

Advances in intraocular surgery have decreased the incidence of corneal complications that result in corneal failure requiring transplantation. Interest continues in further refining surgery to minimize endothelial cell damage. New irrigating solutions, viscoelastic substances, and even new techniques have been introduced. Debate continues over certain issues, such as intraocular lens choice in the absence of capsular support. Improved design has prompted many early critics to regain confidence in the anterior chamber lens. Literature of recent years also reflects a shift in focus toward hastening recovery time and maximizing uncorrected visual acuity through the advantageous control of corneal astigmatism. Several reports this year may herald the next wave of interest, that surrounding intraocular surgery after refractive corneal surgery.

Autoimmunity to a cornea-associated stromal antigen in patients with Mooren's ulcer

PURPOSE

To purify and characterize a cornea-associated antigen (CO-Ag) and to determine antibody levels to CO-Ag in patients with Mooren's ulcer.

METHOD

Standard ion exchange and gel filtration chromatographies were used to isolate and purify CO-Ag from crude bovine stromal extracts. The serum of a patient with Mooren's ulcer, containing a high level of antibodies directed against CO-Ag, was used to monitor isolation procedures. Using this newly purified CO-Ag, an enzyme-linked immunoabsorbent assay was used to detect the presence of antibodies to CO-Ag in the sera of other patients with Mooren's ulcer.

RESULTS

CO-Ag was purified to apparent homogeneity from bovine corneal stromal extracts by a series of ion exchange chromatographies and gel filtration. Polyacrylamide gel electrophoresis showed that CO-Ag was a tetramer with a molecular weight of 30,000 d that may dissociate under denaturing conditions into a monomer of 7000 d. Strong indirect immunofluorescent staining was demonstrated of the stroma by guinea pig anti-CO-Ag antibody. A statistically significant difference in the level of specific antibodies to CO-Ag between patients with Mooren's ulcer and controls was found (P < 0.001). The antibody level was elevated in patients with Mooren's ulcer (mean antibody level, 0.58 +/- 0.13) compared with the controls (mean antibody level, 0.22 +/- 0.04).

CONCLUSION

These results suggest that an autoantigen exists in the corneal stroma that reacts with serum antibodies from patients with Mooren's ulcer. The availability of a purified corneal antigen could facilitate the diagnosis and define the pathogenetic mechanisms in Mooren's ulcer.

The association of lymphocytotoxic antibodies with corneal allograft rejection in high risk patients. The Collaborative Corneal Transplantation Studies Research Group

The Collaborative Corneal Transplantation Studies are a pair of multicenter prospective clinical trials evaluating the effectiveness of histocompatibility matching in high risk keratoplasty patients. The antigen matching study (AMS) evaluated HLA matching in patients without circulating lymphocytotoxic antibody to HLA antigens and the cross-match study (CS) evaluated the effect of using cross-match-negative donors in patients with identified circulating lymphocytotoxic antibodies to HLA antigens. Sera from 510 patients considered for enrollment in the studies were screened preoperatively for the presence of anti-class I lymphocytotoxic antibodies (LA). The 42 patients (8%) found to have detectable LA entered the CS. The 468 patients found not to have detectable LA preoperatively entered the AMS. Fifteen of the 37 transplanted CS patients were found to have donor-specific anti-class I antibody (before or after surgery). These patients were also screened for anti-class II LA and 25 had anti-class II panel reactive antibody > or = 5%. Forty-nine of the 419 transplanted AMS patients (12%) were found to have produced anti-class I LA after surgery, and in 19 patients, antibody specificities were those of donor HLA antigens. There was a significant association between the number of mismatched class I antigens and the number of donor-specific LA produced. The production of LA by AMS patients was significantly associated with reaction episodes; eighty-two percent of patients (40 of 49) with LA had reaction, compared with 63% of patients (230 of 365) without LA (P = 0.02). Likewise, production of donor-specific LA was significantly associated with immune-mediated graft failure (P = 0.025). For CS patients, there was no correlation between the production of donor-specific anti-class I or nonspecific anti-class II antibodies and graft outcome. However, the CS patients had poorer graft survival than did AMS patients at 3 years (57% vs. 66%, P = 0.01). These data demonstrate that LA, especially directed against donor class I HLA antigens following corneal transplantation in high risk patients, are associated with immune graft rejection and can be an indicator of allograft rejection.

Patient-reported symptoms associated with graft reactions in high-risk patients in the collaborative corneal transplantation studies. Collaborative Corneal Transplantation Studies Research Group

The Collaborative Corneal Transplantation Studies (CCTS) were designed to evaluate the effect of donor-recipient histocompatibility matching and cross-matching on the survival of corneal transplants in high-risk patients. We now report on the role of symptoms in the detection of corneal allograft reactions in the CCTS and on the relationship between symptom reporting and graft survival. The 456 patients transplanted in the CCTS were followed for a minimum of 2 years or until graft failure. The follow-up protocol included 11 scheduled examinations in the first year, four examinations during the second year, and examinations every 6 months thereafter. Interim examinations were performed in response to patient-reported symptoms. At every examination, patients were asked specifically if they had redness, sensitivity to light, loss of vision, or pain (RSVP). Of the 456 patients transplanted, 62% had at least one graft reaction. Patients diagnosed with reactions at scheduled visits in the first postoperative year were 2.5 times more likely to report symptoms than those without reactions. Reports of red eye and vision loss were strongly associated with allograft reaction. However, these symptoms were neither highly sensitive nor specific for reaction (sensitivity = 46%, specificity = 70% at 6 months). The severity of reaction influenced the reporting of symptoms: 69% of patients with severe reactions reported symptoms versus 48% of patients with mild reactions (p < 0.001). The only patient characteristic associated with reliable symptom reporting was age, with younger patients with reactions being more likely to report symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of confocal microscopy in evaluating corneal wound healing after excimer laser keratectomy

Corneal wound healing following excimer laser keratectomy is the major cause of regression of treatment results. The amount of anterior stromal haze that develops may be influenced by topical medications. Over a period of 6 months, we followed 15 New Zealand white rabbit eyes that underwent excimer laser keratectomy with the VISX 193-nm ArF laser at a fluence of 150 mJ/cm2 for a depth of 130 microns. Eyes were randomized to treatment with prednisolone acetate, diclofenac sodium (Voltaren), a combination of both, and a control group. Drops were administered four times a day for 1 week, two times a day for 3 weeks, and the drops were then tapered. All eyes were reepithelialized by 5 to 7 days. The tandem scanning confocal microscope (TSCM) was used to evaluate the corneal wound in vivo weekly for a month and monthly for 6 months. During the early postoperative period, the TSCM revealed significant anterior stromal keratocyte activation with cell elongation and the spindle-shaped appearance of fibroblasts in all groups. Collagenous stromal scarring was evident initially, then slowly decreased in all treatment groups. This study shows that TSCM is clinically useful for successive in vivo examinations of corneal wounds after excimer laser keratectomy and for comparing the effects of various topical medications.

Risk factors for corneal graft failure and rejection in the collaborative corneal transplantation studies. Collaborative Corneal Transplantation Studies Research Group

PURPOSE

To evaluate comprehensively the magnitude of suspected risk factors for corneal graft failure from any cause, failure from rejection, and immunologic reaction in patients at high risk for graft failure after corneal transplantation.

METHODS

The records of the 457 participants in the Collaborative Corneal Transplantation Studies were reviewed. All participants had at least two quadrants of stromal vascularization and/or a history or previous graft rejection. Patients were followed for 2 to 5 years. Characteristics of the patient, study eye, donor, donor-recipient histocompatibility, and surgical procedure were examined for their association with the graft outcomes of failure from any cause, rejection failure, and immunologic reaction. Multivariate survival analysis techniques were used to estimate rates of graft outcome events and to estimate the magnitude of risk factors.

RESULTS

Many apparent risk factors did not maintain their association with graft outcomes after adjustment for other risk factors. Young recipient age, the number of previous grafts, history of previous anterior segment surgery, preoperative glaucoma, quadrants of anterior synechiae, quadrants of stromal vessels, a primary diagnosis of chemical burn, and blood group ABO incompatibility were among the strongest risk factors identified for graft failure. Donor and corneal preservation characteristics had little influence on graft outcome.

CONCLUSIONS

Risk of graft failure varies substantially, even within a high-risk population. The number of risk factors present should be considered by the patient and surgeon when contemplating transplantation and planning follow-up.

Reassembly of corneal epithelial adhesion structures after excimer laser keratectomy in humans

OBJECTIVE

To determine the pattern of long-term reformation of the adhesion structures after excimer laser phototherapeutic keratectomy.

METHODS

Four corneal buttons were removed at penetrating keratoplasty 6 to 15 months after initial excimer laser phototherapeutic keratectomy. Morphometric analysis of electron micrographs of the wound bed was performed to determine the extent and pattern of reformation of hemidesmosomes, anchoring fibrils, and basal laminae.

RESULTS

Eight percent of the basal epithelial cells had underlying normal anchoring fibrils at 6 months, compared with 35% at 15 months. The percentage of basal cell membrane occupied by hemidesmosomes remained fairly constant (35.2% to 37.7%). With the exception of a localized area of multilamination seen at 9 months, the cross-sectional area of basal lamina per 100 microns of basal cell membrane increased with the duration of wound healing (18.0 microns 2 at 6 months, 24.4 microns 2 at 15 months) but remained below normal levels (32 microns 2).

CONCLUSIONS

These data suggest that after human excimer keratectomy, the anchoring fibrils and basal lamina do not completely normalize even after 15 months.

Corneal decompensation in mitochondrial ophthalmoplegia plus (Kearns-Sayre) syndrome. A clinicopathologic case report

The authors describe the clinical, molecular genetic, and pathologic findings of a patient with corneal decompensation associated with the mitochondrial ophthalmoplegia plus (Kearns-Sayre) syndrome. Ultrastructurally abnormal mitochondria were observed and possibly implicate this organelle in the pathogenesis of corneal edema.

Stripping of Descemet's membrane: a clinicopathologic correlation

We describe a case of accidental injection of sodium hyaluronate (Healon) anterior to Descemet's membrane that caused the membrane to become almost completely detached. The patient eventually underwent penetrating keratoplasty, permitting histopathologic study of the detachment. Sodium hyaluronate globules in the space between the posterior stroma and Descemet's membrane were demonstrated by light and electron microscopy. In addition, 111 consecutive cases of Descemet's membrane detachment identified pathologically were reviewed to identify potential predisposing risk factors and determine corneal pathologic changes. A history of previous intraocular surgery was present in 89 (80%) of the cases; cataract surgery, the most common, had occurred in 52 (58%). Frequent associated corneal pathologic findings were bullous keratopathy in 48 (43%) of the specimens, and scarring and vascularization in 33 (29.7%). In one case that was identified and studied histopathologically, a 90% detachment of Descemet's membrane was noted clinically following the reformation of the anterior chamber with sodium hyaluronate. We conclude that in the cases of Descemet's membrane detachment that came to pathologic examination, intraocular surgery was a major predisposing risk factor. Corneal pathologic changes, which were common, possibly masked the clinical diagnosis of Descemet's membrane detachment in some cases.

Visual outcome after surgery for Peters' anomaly

The authors reviewed the charts of 22 patients with Peters' anomaly. Various surgical procedures were performed on 30 eyes of 18 patients (mean number of procedures = 3.3 per eye). Follow-up averaged six years. Visual acuity varied widely, with six eyes having an acuity of 20/400 or better, and 11 eyes with no light perception. Concomitant or secondary glaucoma required a greater number of surgical procedures (4.1 vs 3.4) per eye and was associated with a poorer visual outcome. No eyes with glaucoma had visual acuity better than 20/400. In bilaterally operated patients, visual results in one eye were independent of the outcome of the fellow eye. The range of visual acuity in bilaterally operated patients was similar to the vision in those operated unilaterally. Visual outcome in patients with Peters' anomaly remains guarded. With modern surgical techniques and aggressive attempts at visual rehabilitation, many patients may benefit from surgery. Some patients may have moderately good visual acuity for months or years before vision is lost. In the interim they may learn tasks they may not have otherwise acquired.

Effectiveness of histocompatibility matching in high-risk corneal transplantation: a summary of results from the Collaborative Corneal Transplantation Studies

The Collaborative Corneal Transplantation Studies (CCTS) were designed to evaluate the effect of donor-recipient histocompatibility matching and crossmatching on the survival of corneal transplants in high-risk patients. Corneas were allocated to the 419 patients in the double-masked Antigen Matching Study on the basis of HLA-A,-B and HLA-DR antigen match. ABO blood group compatibility was determined but not used for recipient selection. The 37 patients in the Crossmatch Study were randomly assigned to receive a cornea from either a positively or negatively crossmatched donor. All patients received topical steroid therapy according to a standard protocol. Matching for HLA-A,-B and HLA-DR antigens had no effect on overall graft survival, the incidence of irreversible rejection, or the incidence of rejection episodes. The positive group in the Crossmatch Study had fewer graft failures, rejection failures, and rejection episodes than the negative group; however, these differences were not statistically significant. The estimated proportion of eyes with failure from rejection by 3 years was 30% for the ABO-incompatible group and 16% for the ABO-compatible group (relative risk, 1.98; 95% confidence interval, 1.15 to 3.13). These studies demonstrate that, for high-risk patients who are immunosuppressed by topical steroid therapy: 1) neither HLA-A.-B nor HLA-DR antigen matching substantially reduced the likelihood of corneal graft failure; 2) a positive donor-recipient crossmatch did not increase the risk of corneal graft failure; and 3) ABO blood group matching may be effective in reducing the risk of graft failure from rejection.

Recurrent keratoconus

Keratoconus is a progressive, noninflammatory, nonvascular axial corneal ectasia, with unclear etiology and pathogenesis. It has a prevalence of 50-230 per 100,000 and is a bilateral disorder in up to 90% of cases. The onset of keratoconus is usually at puberty and progresses over 10-20 years producing an irregular myopic astigmatism. The treatment depends on the severity of the irregular astigmatism. Advanced keratoconus, which cannot be treated with contact lenses, requires a surgical procedure--either penetrating keratoplasty, epikeratophakia, or thermokeratoplasty. The results of penetrating keratoplasty are good, with success rates of > 90% of the cases. Recurrence of keratoconus following penetrating keratoplasty has been previously reported, based on a clinical diagnosis, and confirmed by histopathological examination. We report the clinicopathologic features of two further cases of recurrent keratoconus.

A clinicopathologic study of posterior polymorphous dystrophy:implications for pathogenetic mechanism of the associated glaucoma

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Effect of cataract on a scotopic sensitivity screening test for glaucoma

We investigated whether cataract decreases whole-field scotopic sensitivity, a measurement used for the detection of early glaucoma damage. The study population consisted of 33 patients scheduled for cataract surgery. Patients were >/=50 years old and had no ocular disease except senile cataract. The whole-field scotopic sensitivity of one eye of each subject was measured 1 day before and 3 months after cataract surgery. That of six persons of similar age without cataract was also measured twice, 3 months apart. Cataract extraction was associated with significantly improved sensitivity (p = 0.005). With stratification by cataract type, only persons with nuclear sclerosis demonstrated a significantly improved sensitivity after cataract surgery (p = 0.03). The magnitude of sensitivity improvement after surgery did not differ significantly between patients with mild compared to moderate cataract. Multiple regression analysis revealed that age, preoperative intraocular pressure, change in visual acuity, cataract type, and cataract severity were not independently significant predictors of change in sensitivity after cataract surgery. We conclude that cataract may alter the whole-field scotopic sensitivity score and may need to be taken into account in its use for glaucoma screening.

Suture abscesses after penetrating keratoplasty

Eighteen suture abscesses that developed after penetrating keratoplasty in 15 patients were reviewed. The time from keratoplasty to the diagnosis of an abscess ranged from 1 to 53 months with a mean of 21.5 months. In 13 of the 18 cases, the patient was taking topical steroids at the time of diagnosis. All were culture-proven bacterial ulcers, except for one case that had a positive Gram's stain, but no growth on culture. The organisms cultured were Staphylococcus epidemidis (six eyes), Streptococcus pneumoniae (five eyes), Sta. aureus (four eyes), Str. viridans (two eyes), Klebsiella oxytoca (one eye), Serratia marcescens (one eye), Moraxella sp (one eye), and Escherichia coli (one eye). The offending suture was removed in all cases, and the eyes were treated with topical fortified antibiotics (cefazolin and tobramycin). After treatment, 67% (12 of 18 eyes) had clear grafts, 17% (three of 18 eyes) were scarred, and 16% (three of 19 eyes) had failed grafts. Intensive topical steroid therapy was used when a subsequent graft rejection developed. Retained sutures following corneal transplants can result in sight-threatening infections and should be considered for removal as soon as the wound is well healed.

Intraocular cilia. Report of six cases of 6 weeks' to 32 years' duration

In this study, we describe the clinicopathologic features seen in six cases of intraocular cilia and review the features of previously reported cases. Ultrastructural studies of the cilia showed partial loss of the cuticle layer, diffuse accumulation of small electron-dense granules in cuticle and cortical cells, and loss of continuous cell membranes of the cortex. The cilia were almost completely intact in most of our cases. Intraocular cilia can be tolerated for long periods.