Is the whitening effect of charcoal-based dentifrices related to their abrasive potential or the ability of charcoal to adsorb dyes?

OBJECTIVES

To evaluate if tooth color alteration of activated charcoal-based dentifrices may be attributed to the dye adsorption potential of charcoal (chemical action - C - slurry only) or to the association of dye adsorption with abrasion (chemo-mechanical action - CM- slurry/toothbrushing). Potential adverse effects in surface roughness, gloss, and wear were also assessed.

METHODS

Bovine enamel/dentin specimens were randomly allocated into the groups according to treatments and test model (n = 15): deionized water (negative control- NC); Colgate Maximum Anticaries Protection (conventional toothpaste- positive control- PC); Colgate Luminous White Activated Charcoal (LW); Oral-B 3D White Therapy Charcoal (WT); Curaprox Black is White (BW); Dermavita Whitemax (Activated charcoal powder- WP). Specimens were exposed to the C or CM models, in 28-day staining-treatment cycling. Color change (ΔE00), whiteness index (ΔWID), percentage of alteration of surface roughness (%Raalt), and gloss (%GUalt) were calculated. Additional specimens (n = 9) were indented with a Knoop diamond and subjected to 100,000 abrasion cycles. Enamel wear was determined by calculating the decrease in indentations geometry. Data were analyzed by ANOVA/Tukey tests (α = 0.05).

RESULTS

The CM-model produced lower color change (staining) than C (p = 0.0001). PC, LW, WT, BW, and WP showed similar color results for both models, differing from NC (p < 0.05).%Ra and%GU did not differ among the C-model groups (p > 0.05) and WP exhibited the highest variation (%Ra and%GU) under CM-model. Enamel wear values were lowest in the NC and PC groups, intermediate for LW, WT, BW, and highest for the WP (p < 0.05).

CONCLUSION

Activated charcoal-based dentifrices have a similar ability to minimize tooth staining as the conventional toothpaste, with increased enamel wear potential in the long term (after 100,000 cycles). The activated charcoal powder damaged the enamel surface, showing a higher deleterious effect on enamel roughness, gloss, and wear.

CLINICAL SIGNIFICANCE

Dentifrices containing activated charcoal do not provide superior results to minimize tooth staining compared to conventional toothpaste. Charcoal powder should be used with caution because it promotes higher superficial alterations on the enamel surface.

Patient-reported outcome measures for a large cohort of serum eye drops recipients in the UK

INTRODUCTION

Serum eye drops (SED) are an important treatment for patients with chronic and severe ocular surface disease (OSD). Despite a long history of use, there is a paucity of information on patient-reported outcomes, particularly comparing autologous SED (Auto-SED) and allogeneic SED (Allo-SED). National Health Service Blood and Transplant is the national provider of SED service for patients in the UK.

PURPOSE

To evaluate and compare patient-reported outcome measures (PROMs) in patients receiving Auto-SED and Allo-SED for severe OSD.

MATERIALS AND METHODS

PROMs were retrospectively collected from all new patients commencing treatment with Auto-SED and Allo-SED between January 2017 and September 2018, using the Ocular Surface Disease Index (OSDI) 12-item questionnaire. A linear mixed model was used to evaluate the change in OSDI scores between baseline and follow-up.

RESULTS

During the study period, 279 patients who received either Auto-SED (n = 71) or Allo-SED (n = 208) were included in the analysis. Baseline and follow-up OSDI scores were available for 161 of these (49 Auto-SED and 112 Allo-SED). There was a significant reduction in mean OSDI score for both Auto-SED (59.06-24.63, p < 0.001) and Allo-SED (64.21-34.37, p < 0.001). There was no significant difference between Auto-SED and Allo-SED patients in terms of the reduction in the OSDI score (p = 0.27).

CONCLUSION

Both Auto-SED and Allo-SED were associated with improvements in the quality of life of patients with chronic and severe OSD. Auto-SED and Allo-SED were equally effective in relieving the symptoms of OSD.

Pathophysiology of aniridia-associated keratopathy: Developmental aspects and unanswered questions

Aniridia, a rare congenital disease, is often characterized by a progressive, pronounced limbal insufficiency and ocular surface pathology termed aniridia-associated keratopathy (AAK). Due to the characteristics of AAK and its bilateral nature, clinical management is challenging and complicated by the multiple coexisting ocular and systemic morbidities in aniridia. Although it is primarily assumed that AAK originates from a congenital limbal stem cell deficiency, in recent years AAK and its pathogenesis has been questioned in the light of new evidence and a refined understanding of ocular development and the biology of limbal stem cells (LSCs) and their niche. Here, by consolidating and comparing the latest clinical and preclinical evidence, we discuss key unanswered questions regarding ocular developmental aspects crucial to AAK. We also highlight hypotheses on the potential role of LSCs and the ocular surface microenvironment in AAK. The insights thus gained lead to a greater appreciation for the role of developmental and cellular processes in the emergence of AAK. They also highlight areas for future research to enable a deeper understanding of aniridia, and thereby the potential to develop new treatments for this rare but blinding ocular surface disease.

A systematic review of cellular therapies for the treatment of limbal stem cell deficiency affecting one or both eyes

PURPOSE

This systematic review (SR) assessed the efficacy, safety and cost-effectiveness of cell-based therapy to manage limbal stem cell deficiency (LSCD), a sight-threatening orphan condition most frequently associated with severe chemical or thermal burns. LSCD has historically been treated by transplanting limbal tissue. In 1997, a new treatment, cultured limbal epithelial autografts, was described for unilateral LSCD. In cases of bilateral disease cultured autologous oral mucosa stem cells have been used. The relative efficacy of different cultured tissue procedures is unknown.

METHODS

A protocol was registered with PROSPERO (CRD42017081117). Searches were conducted in 14 databases and 6 conference websites. Two reviewers independently selected studies, conducted data extraction and assessed risk of bias. One reviewer extracted individual patient data (IPD); a second checked extracted data. Data were assessed to determine the feasibility of statistical analysis, with Bayesian synthesis used to estimate improvement achieved by different treatments.

RESULTS

Fifty-two studies were eligible for inclusion (1113 eyes); 41 studies (716 eyes) reported IPD. No evidence was identified on cost-effectiveness. This SR was unable to confirm that any of the types of ex vivo cultured stem cell transplants identified for LSCD treatment were statistically superior when assessed against the outcomes of interest.

CONCLUSIONS

We believe this SR is the first to include IPD analysis of LSCD data. There is no evidence for the superiority of any method of limbal stem cell transplant. Confirmation of the safety and efficacy of this treatment modality is challenging due to heterogeneity within and between the studies identified. Therefore, recommendations for future research are proposed.

Microbial keratitis in corneal grafts: predisposing factors and outcomes

PurposeTo identify the nature of microbial keratitis in corneal grafts and the clinical outcomes at a tertiary hospital in the United Kingdom.Patients and methodsA retrospective case series of microbial keratitis in corneal grafts at the Royal Victoria Infirmary, Newcastle upon Tyne over a 17-year period (1997-2014).ResultsA total of 759 consecutive corneal grafts were identified from the Cornea Transplantation database. Of these, 59 episodes of microbial keratitis occurred in 41 eyes of 41 patients (5.4%; 19 male, 46.3%). Median patient age was 73 years (SD=19.4 years). The most common indication for corneal transplantation was bullous keratopathy (11/41, 26.8%). There were 34/59 (57.6%) episodes of culture-positive graft keratitis; Streptococcus pneumoniae and Staphylococcus aureus were each isolated in 5/34 (14.7%) culture-positive episodes. In all, 35/59 (59.3%) episodes of microbial keratitis occurred in 22 previously failed grafts and 3 de novo graft failures. Gram-negative keratitis was more likely to cause reduced BCVA after (χ²-test, P=0.02). Median graft duration was 49.5 months (SD=43.7 months). Failed grafts were significantly older (median 69 vs 27 months, P=0.009).ConclusionThis represents the longest published follow-up data on microbial keratitis and is the only of its kind in the United Kingdom. The incidence of 5.4% is comparable to that within the developed world. Graft age was significantly associated with graft failure in microbial keratitis; the ongoing risk of microbial keratitis warrants providing patients with long-term open access to hospital eye services.

Comparison of the Effect of Sodium Hyaluronate (Ophthalin®) and Hydroxypropylmethylcellulose (HPMC-Ophtal®) on Corneal Endothelium, Central Corneal Thickness, and Intraocular Pressure after Phacoemulsification

PURPOSE

To prospectively evaluate the effects of 2% hydroxypropyl-methylcellulose (HPMC-Ophtal) and sodium hyaluronate 1% (Ophthalin) on intraocular pressure, corneal thickness, and endothelial cell loss in small incision cataract surgery with implant.

METHODS

A total of 110 patients undergoing routine phacoemulsification with implant received either 2% hydroxypropyl methylcellulose or sodium hyaluronate 1% as ophthalmic viscosurgical device. Pre- and postoperative slitlamp examination, intraocular pressure measurement (preoperatively and at 1-4 hours, 1 day, and 7 days postoperatively), ultrasonic pachymetry (preoperatively and at 1 week, 4-6 weeks, and 12 weeks post operatively), and corneal endothelial cell count (preoperatively and 12 weeks postoperatively) were performed. Data were analyzed using two-way analysis of variance.

RESULTS

All measurements were comparable between the two groups preoperatively. Intraocular pressure was significantly lower in the Ophthalin group at 1 day post operatively, while no significant difference was found between the two groups on the 1-4 hours and 7 days examination. The central corneal thickness was not significantly different between the two groups at any postoperative visit . However, the mean cell density demonstrated a significant fall of 11.76% for Ophthalin and 4.27% for HPMC-Ophtal at 12 weeks post-operatively, the difference between the two being significant (p=0.009).

CONCLUSIONS

2% Hydroxypropyl methylcellulose, compared with sodium hyaluronate 1%, is superior in protecting the corneal endothelial cells, has the same effect on central corneal thickness, and is associated with slightly higher intraocular pressure 1 day post operatively. It compares favorably with sodium hyaluronate 1% and can be used as an effective and cheaper alternative in routine small incision cataract surgery with implant.

Gamma-irradiated human amniotic membrane decellularised with sodium dodecyl sulfate is a more efficient substrate for the ex vivo expansion of limbal stem cells

The gold standard substrate for the ex vivo expansion of human limbal stem cells (LSCs) remains the human amniotic membrane (HAM) but this is not a defined substrate and is subject to biological variability and the potential to transmit disease. To better define HAM and mitigate the risk of disease transmission, we sought to determine if decellularisation and/or γ-irradiation have an adverse effect on culture growth and LSC phenotype. Ex vivo limbal explant cultures were set up on fresh HAM, HAM decellularised with 0.5M NaOH, and 0.5% (w/v) sodium dodecyl sulfate (SDS) with or without γ-irradiation. Explant growth rate was measured and LSC phenotype was characterised by histology, immunostaining and qRT-PCR (ABCG2, ΔNp63, Ki67, CK12, and CK13). Ƴ-irradiation marginally stiffened HAM, as measured by Brillouin spectromicroscopy. HAM stiffness and γ-irradiation did not significantly affect the LSC phenotype, however LSCs expanded significantly faster on Ƴ-irradiated SDS decellularised HAM (p<0.05) which was also corroborated by the highest expression of Ki67 and putative LSC marker, ABCG2. Colony forming efficiency assays showed a greater yield and proportion of holoclones in cells cultured on Ƴ-irradiated SDS decellularised HAM. Together our data indicate that SDS decellularised HAM may be a more efficacious substrate for the expansion of LSCs and the use of a γ-irradiated HAM allows the user to start the manufacturing process with a sterile substrate, potentially making it safer.

STATEMENT OF SIGNIFICANCE

Despite its disadvantages, including its biological variability and its ability to transfer disease, human amniotic membrane (HAM) remains the gold standard substrate for limbal stem cell (LSC) culture. To address these disadvantages, we used a decellularised HAM sterilised by gamma-irradiation for LSC culture. We cultured LSCs on fresh HAM, HAM decellularised with NaOH, HAM decellularised with sodium dodecyl sulfate (SDS) and HAM decellularised with SDS and sterilised with gamma-irradiation. We demonstrated that although HAM decellularised with SDS and sterilised with gamma-irradiation is significantly stiffer this does not affect LSC culture growth rate or the phenotype of cultured LSCs. We therefore recommend the use of SDS decellularised gamma-irradiated HAM in future LSC clinical trials.

An 8-year longitudinal analysis of UK ophthalmic publication rates

Purpose44.5% of abstracts presented at biomedical conferences are published. 26.5% of abstracts presented are basic science. The 2005 Walport Report reformed clinical academic training in the United Kingdom (UK) to promote trainee research. This study aims to analyse UK Ophthalmology research output following the reconstruction of clinical academic training.Patients and Methods1862 abstracts presented at The Royal College of Ophthalmologists' (RCOphth) Annual Congress from May 2005-May 2012 were examined using PubMed. Publication trends were analysed using SPSS v22 (IBM), using Spearman's rank coefficient and Mann-Whitney U test.Results44 (2.4%) abstracts were randomized controlled trials (RCTs), 88 (4.7%) basic science, and 231 (12.4%) oral presentations. 486 (26.6%) abstracts were published to a mean impact factor (IF) of 2.39 (95% CI 2.21-2.57). Mean time to publication from presentation was 15.17 (13.88-16.48) months, negatively correlating with IF (r=-0.149, P<0.003). Oral presentation (P<0.0001), RCTs (P=0.002), and basic science (P<0.0001) abstracts all made publication significantly more likely, with hazard ratios of 2.63 (2.13-2.24), 2.07 (1.3-3.2), and 1.92 (1.41-2.59), respectively. Higher IF was associated with oral presentation (3.4 vs 2.16, P<0.0001), basic science (3.57 vs 2.35, P<0.0001), and RCTs (4.78 vs 2.38, P=0.002). No significant change in publication rate was seen across the 8 years (P=0.61).ConclusionThe proportion of basic science and total abstracts published that are presented at the RCOphth is lower than that in other biomedical conferences. RCTs, basic science abstracts, and oral presentations are more likely to be published. There was no improvement in publication rates following the 2005 Walport Report.

Do topical ophthalmic corticosteroids suppress the hypothalmic-pituitary-adrenal axis in post-penetrating keratoplasty patients?

PURPOSE

To establish whether hypothalmic-pituitary-adrenal axis suppression is possible secondary to long-term topical ophthalmic corticosteroid use in patients who have undergone penetrating keratoplasty (PKP).

METHODS

Patients who had undergone a PKP and had been using corticosteroid-based eye drops continuously for more than 6 months, with no history of concomitant steroid (oral, inhaled, or cutaneous) use, were included within the study. A low-dose short Synacthen (LDSST) test was performed in each patient followed later by a short Synacthen test (SST). The mean SST and LDSST after 30 min were calculated along with their corresponding 95% confidence intervals (CIs). Correlation between both baseline SST and baseline LDSST with duration of treatment was determined using Spearman's correlation.

RESULTS

In all, 20 patients were included within the study. The mean duration treatment was 28.2 months (range 11-96 months). All patients had normal baseline cortisol levels in both SST and LDSST tests. The mean 30 min SST was 753.8 nmol/l (95%CI: 696.6 nmol/l, 811.0 nmol/l) and no patients displayed inadequate adrenal response. The mean 30 min LDSST was 709.8 nmol/l (95%CI: 665.1 nmol/l, 754.5 nmol/l) and only one patient had an inadequate adrenal response. There was no correlation between baseline SST or LDSST and duration of treatment.

CONCLUSIONS

This study found no evidence that patients using continuous long-term corticosteroid eye drops after PKP experienced inadequate adrenal response. We did not find any evidence of a negative correlation between length of treatment and SST or LDSST measurements at baseline.

Postkeratoplasty emergency visits—a review of 100 consecutive visits

PURPOSE

Preoperative counselling for penetrating keratoplasty should include awareness of symptoms and signs of possible complications as early presentation can enhance long-term success. In our corneal transplantation service, all patients are routinely instructed to arrange a same day emergency visit through a dedicated telephone line if they experience any symptoms in eyes that have undergone keratoplasty. This study was designed to evaluate the reason for presentation, management outcome of each visit and the efficiency of the system in management of postkeratoplasty complications.

METHODS

A review of 100 consecutive emergency visits by postpenetrating keratoplasty (PKP) patients in a tertiary eye care centre was included.

RESULTS

Sixty-two patients with varied preoperative diagnoses presented during the review period. Sixteen visits were within the first month after surgery and 40 visits within the first year. Ten patients (16%) sought consultation more than twice during the study period with one patient presenting five times. Pain and grittiness were the main presenting symptoms (68%). Loose corneal suture (25%) necessitating removal was the most common diagnosis. Sixteen visits resulted in hospital admission for treatment. The graft survived in all patients and the visual acuity was preserved in 95% of our patients.

CONCLUSION

Most corneal surgeons educate their patients to seek prompt treatment for symptoms such as redness, sensitivity to light, loss of vision, pain, or any other symptoms in eyes that have undergone keratoplasty. Early intervention of sight threatening complications increases the chance of graft survival and best-obtained vision. This review shows a simple open access system facilitates early presentation and successful management of postgraft complications.

Development of organised conjunctival leucocyte aggregates after corneal transplantation in rats

AIM

To investigate the development of lymphoid aggregates in the conjunctiva after corneal transplantation in rats.

METHODS

LEW or PVG strain corneas were transplanted orthotopically to PVG rats. Cornea and conjunctiva were examined clinically for up to 42 days. Eyes were removed with attached conjunctiva on days 10 and 15 after transplantation (before and during rejection), together with normal eyes, fixed, paraffin embedded, and examined immunohistochemically.

RESULTS

Clinically, the temporal half of the upper palpebral conjunctiva of recipients of 10/19 allografts and 1/10 isografts developed pronounced swelling, correlating with inflammation and rejection. Histologically, the swelling comprised leucocytic aggregates with an altered overlying epithelium. Aggregates contained granulocytes, macrophages, and cells expressing major histocompatibility complex (MHC) class II, CD4, and CD8, all more numerous in allograft associated conjunctiva. Class II+ cells were more abundant at the surface, whereas macrophages and T cells were more numerous in the deeper stroma. There were few B cells. There was greater CD54 expression by vascular endothelium in allograft associated aggregates. Cells expressing TNFalpha and IFNgamma but not IL1beta were present in stromal and superficial areas.

CONCLUSIONS

Corneal transplantation in rats induces the development of organised conjunctival leucocytic aggregates in a fixed location that are significantly more pronounced in recipients of allografts compared with isografts and show characteristics of a Th1 type immune response. These aggregates have characteristics of conjunctiva associated lymphoid tissue and may be sites of presentation of graft antigens and lymphocyte proliferation at the ocular surface.

A randomised, crossover, multicentre study to compare the performance of 0.1% (w/v) sodium hyaluronate with 1.4% (w/v) polyvinyl alcohol in the alleviation of symptoms associated with dry eye syndrome

AIMS

To assess the safety and performance of a 0.1% (w/v) solution of sodium hyaluronate (HA, Fermavisc, in the alleviation of symptoms of severe dry eye in comparison with a 1.4% (w/v) solution of polyvinyl alcohol.

METHODS

A randomised, crossover, multicentre study carried out at eight centres in the UK. Eligible patients giving written informed consent were randomised to the order in which they would receive the two study products. Each treatment period lasted for 4 weeks, then the patient crossed over to the other study product. Symptoms of burning and grittiness were assessed by visual analogue scale (VAS) at each study visit and other objective clinical assessments of ocular structure and function were carried out at baseline and the end of each treatment period.

RESULTS

Thirty-nine patients were entered into the study and 32 completed both treatment periods and were included in the statistical analyses. A significant improvement in the patients' VAS assessment of burning was seen after treatment with HA (P = 0.03, 95% Confidence Interval: -23.5 to -1.1). This treatment also resulted in a significantly lower rose bengal staining score (P = 0.04, 95% Confidence Interval: -1.62 to -0.05 for the right eye).

CONCLUSION

The results show a significant clinical benefit in terms of relief of the symptom of burning when HA is applied topically to the eye three or four times per day or as required. HA also appears to have a protective effect on the corneal epithelium, as shown by a reduction in the level of staining of corneal epithelial cells by rose bengal. This study confirms that Fermavisc is a safe and effective product for use in the alleviation of symptoms of severe dry eye syndrome.

Tumor necrosis factor-alpha and interleukin-1beta mediate the production of nitric oxide involved in the pathogenesis of ifosfamide induced hemorrhagic cystitis in mice

PURPOSE

We investigated the participation of nitric oxide in ifosfamide induced hemorrhagic cystitis in mice, and the involvement of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta in the induction of nitric oxide production in this model.

MATERIALS AND METHODS

Hemorrhagic cystitis was induced in mice by 100 to 400 mg./kg. ifosfamide and evaluated 6, 12, 24 or 48 hours thereafter by certain parameters, including vesical edema measurements, microscopic analysis and immunohistochemical testing for inducible nitric oxide synthase. Ifosfamide injected mice were pretreated with 10 to 40 mg./kg. of the nitric oxide synthesis inhibitor L-NG-nitroarginine methyl ester, 80 mg./kg. of mesna, a chemical antagonist of acrolein and the urotoxic metabolite of ifosfamide, 50 microl. antiserum against TNF-alpha and IL-1beta per mouse, 45 mg./kg. of the selective TNF-alpha synthesis inhibitor thalidomide or 200 mg./kg. of the TNF-alpha and IL-1beta synthesis inhibitor pentoxifylline.

RESULTS

Ifosfamide induced vesical edema, which peaked 12 hours after ifosfamide injection. Microscopic analysis revealed vascular congestion, edema, hemorrhage, fibrin deposition, neutrophil infiltration and epithelial denudation. Inducible nitric oxide synthase immunolocalization demonstrated intense reactivity to inducible nitric oxide synthase in the cytoplasm of bladder epithelial cells, which showed diffuse necrosis. Pretreatment with mesna reduced the increases in vesical edema, while treatment with L-NG-nitroarginine methyl ester, antiserum to TNF-alpha or IL-1beta, thalidomide or pentoxifylline inhibited vesical edema and microscopic alterations. Antiserum treatments also inhibited the expression of inducible nitric oxide synthase in the urothelium.

CONCLUSIONS

Nitric oxide produced by inducible nitric oxide synthase is involved in urothelial damage and in the inflammatory events leading to hemorrhagic cystitis after ifosfamide administration in mice. The induction of inducible nitric oxide synthase in the urothelium appears to depend on the synergistic effect of IL-1beta and TNF-alpha.

Clinical comparison of ocular blood flow tonometer, Tonopen, and Goldmann applanation tonometer for measuring intraocular pressure in postkeratoplasty eyes

PURPOSE

Intraocular pressure (IOP) measurements vary with different tonometers in irregular corneas. The purpose of our study was to determine the comparability of the ocular blood flow tonometer (OBF) and Tonopen with the Goldmann applanation tonometer (GAT) in measuring IOP in post-keratoplasty eyes.

METHODS

The IOP was measured using the OBF tonometer, GAT, and Tonopen in 69 post-keratoplasty eyes by two observers. The same instruments were used, and the sequence of measurements was randomized. Pachymetry to measure corneal thickness was done in all patients.

RESULTS

Interobserver variation for IOP measured with GAT was statistically significant ( p = 0.039). Two-way analysis of variance (ANOVA), however, did not demonstrate any statistical difference between measurements with the three tonometers and two observers. Corneal thickness did not appear to have an effect on measurements with any of the tonometers.

CONCLUSION

There was no significant difference in the overall accuracy of the OBF tonometer over the Tonopen versus the GAT. The OBF tonometer can be a useful alternative in measuring IOP in post-keratoplasty eyes.

An improved method for examining the corneal endothelium during graft rejection in the rat

An improved method of removing rat corneal endothelial sheets for study of endothelial pathology is described. The method was validated by examining morphological changes and changes in expression of major histocompatibility complex (MHC) and intercellular adhesion molecule (ICAM)-1 on endothelium undergoing immunological rejection. PVG strain rats received LEW strain corneal transplants or corneal isografts. Just prior to and during graft rejection, animals were killed, together with a group of untreated animals. The corneal stroma was injected with dispase or PBS, the cornea was carefully removed, fixed in acetone and the endothelium was gently peeled off and flattened on to a glass slide. Morphological changes, together with MHC class I, class II and ICAM-1 expression were visualised by immuno-histochemical staining and quantified by image analysis. Near complete endothelial sheets were obtained by this method. Because of the thin cell layer, there was minimal background staining, permitting rejection-associated changes to be clearly seen. MHC class I expression on normal endothelium was low and not significantly increased on endothelial cells of allografts at the time of rejection compared with controls (P = 0.1). MHC class II and ICAM-1 were induced de novo, expression being significantly higher on allografts than on isografts (P = 0.004 for MHC class II and P = 0.01 for ICAM-1). MHC class I and II and ICAM-1 were expressed on many infiltrating cells. Thus, this preparation method permits clear identification of the distribution and morphology of infiltrating cells and other mediators of the immune response in the entire donor endothelium. It confirms that MHC class I expression is low during rejection, while MHC class II and ICAM-I are induced de novo and strongly expressed.

Combined interrupted and continuous versus single continuous adjustable suturing in penetrating keratoplasty: a prospective, randomized study of induced astigmatism during the first postoperative year

OBJECTIVE

To compare postoperative astigmatism induced by two different suturing techniques in penetrating keratoplasty (PKP).

DESIGN

A monocenter, prospective, randomized clinical trial with a longitudinal 1-year follow-up.

PARTICIPANTS

A total of 95 eyes undergoing PKP were randomized into 2 groups. Of these, 51 eyes were allocated to the combined interrupted and continuous suturing group (ICS) and 44 eyes to the single continuous adjustable suturing (SCAS) group.

INTERVENTION

In the ICS group, suturing was with a combination of 12 interrupted 10-0 nylon and 1 continuous 11-0 nylon sutures. Eyes in the SCAS group had been sutured with a single running 24-bite 10-0 nylon. Selective suture removal started no earlier than 10 weeks after surgery; suture adjustment could start as soon as possible after surgery.

MAIN OUTCOME MEASURES

Astigmatism was measured by topography, keratometry, and refraction at 3-, 6-, 9-, and 12-month postoperative intervals.

RESULTS

The difference in mean time of suture manipulation between groups was significant (P = 0.0001), with the SCAS starting earlier. A significant decrease in astigmatism occurred by either interrupted suture removal (6.69 +/- 3.11 diopter [D] before to 4.76 +/- 2.99 D after, P = 0.0002) or suture adjustment (7.18 +/- 3.12 D before to 4.46 +/- 3.24 D after, P = 0.0001). However, the net astigmatic reduction in the SCAS group was not significantly greater (P = 0.250) than in the ICS group. Vector change was 7.40 +/- 4.17 D and 6.28 +/- 4.14 D for SCAS and ICS, respectively (P = 0.13). At no interval (3, 6, 9, or 12 months) was there significant difference in astigmatism between the two groups. Refractive astigmatism (cyl, D) at 1 year was 2.66 +/- 1.70 for the ICS and 3.12 +/- 2.62 for the SCAS, but there was no significant treatment effect (P = 0.945). Furthermore, 66% of the ICS eyes and 58% of the SCAS eyes (P = 0.295) were within the astigmatic target of the study (<3.5 D).

CONCLUSIONS

Postkeratoplasty astigmatism can be decreased similarly with either adjustment of a single running suture or selective removal of interrupted sutures. No advantage of the SCAS over ICS in terms of fewer manipulations or less astigmatism was seen as suggested previously.

Surgical control of late postkeratoplasty astigmatism with or without the use of computerized video keratography: a prospective, randomized study

OBJECTIVE

To assess the effectiveness of computerized videokeratography (CVK) in refining the surgical design and in improving predictability of surgical correction of postkeratoplasty astigmatism.

DESIGN

A prospective, controlled, randomized, clinical trial.

PARTICIPANTS

A total of 31 postkeratoplasty eyes, divided into 2 groups (group A, 16 eyes; group B, 15 eyes), with more than 4 diopters (D) of disabling astigmatism were studied.

INTERVENTION

All eyes were treated with a combination of arcuate relaxing incisions and compression sutures. The surgical plan in group A was based on topographic information, whereas in the control group B, the surgical plan was based on information obtained by refraction and keratometry alone.

MAIN OUTCOME MEASURES

Change in the surgical plan induced by the CVK information, astigmatism, topographic patterns, and factors associated with outcome were measured.

RESULTS

In all 16 cases of group A, the use of CVK changed some aspect of the surgical plan. At 12 months after surgery, both groups showed a significant net reduction (P = 0.001) of baseline astigmatism. However, the reduction (47% and 41 % for groups A and B, respectively) did not differ significantly between the two groups. The topographic astigmatism at 12 months measured 4.24 +/- 0.71 D in group A and 5.60 +/- 0.51 D in group B (P = 0.139). Significant differences between the two groups at 12 months were seen only for keratometric astigmatism (3.60 +/- 0.81 D in group A vs. 5.77 +/- 0.52 D in group B, P = 0.035) and refractive astigmatism (2.34 +/- 0.37 D in group A vs. 4.88 +/- 0.52 D in group B, P = 0.000). The mean vector surgical effect was 91 % for group A and 70% for group B. Regular astigmatism patterns had a greater benefit from surgery than irregular patterns (P = 0.008). Previous refractive surgery was associated with less-favorable outcome (P = 0.045).

CONCLUSIONS

The current study indicates that the use of CVK provides a benefit compared to keratometry and refraction alone in the planning and outcome of surgical treatment for high postgraft astigmatism.