Early corneal pachymetry maps after cataract surgery and influence of 3D digital visualization system in minimizing corneal oedema.

PURPOSE: To describe the early topography of corneal swelling occurring after cataract surgery and to evaluate the impact of the three-dimensional (3D) digital visualization system in minimizing corneal oedema. METHODS: Prospective observational, single-centre, consecutive case series of 134 patients undergoing cataract surgery performed by the same surgeon, with either 3D or conventional visualization systems. Eyes were assigned to two groups based on their anterior chamber depth (group ACD ≤3 mm and group ACD >3 mm). Optical coherence tomography was performed to evaluate postoperative corneal swelling. RESULTS: Three corneal swelling profiles were identified on the first postoperative day type 1, limited corneal oedema near peripheral corneal incisions; type 2, dome-shaped corneal swelling spreading from the principal corneal incision and reaching the paracentral cornea; type 3, continuous oedema spreading from the principal incision to central cornea, with a generalized oedema predominating in the upper part of the cornea. On the first day after surgery, in group ACD ≤3 mm, visual acuity was significantly better in patients undergoing surgery with 3D visualization (0.023 vs 0.072 logMar, p = 0.014) with reduced central corneal thickening 17.3 µm (±3.2) in comparison with conventional visualization 44.0 µm (±9.3) (p = 0.0082). In group ACD >3 mm, no significant association was found between the use of the 3D system and pachymetry changes and early visual rehabilitation. On day 21 after surgery, no significant differences in corneal pachymetry values were observed between the two surgical approaches in both groups. CONCLUSIONS: We describe early postoperative corneal map profiles providing insight into the pathogenesis of postoperative corneal swelling and possible prevention strategies. By improving visualization of the narrow surgical space in patients with shallow anterior chambers, the 3D system could help to minimize postoperative corneal oedema.

Corneal staining during cataract surgery: Natural course, ASOCT features, and preventive measures.

We report the natural course of the accidental injection of trypan blue into the corneal stroma while performing a routine cataract surgery by a resident during a training session. The corneal staining resolved with conservative medical treatment over 7 weeks. This case describes the anterior segment optical coherence tomography (ASOCT) features of corneal staining. It emphasizes on the relatively benign nature of this dye and the follow-up course. Causes that may be responsible for this untoward complication are highlighted with the necessary preventive measures that need to be taken care are also discussed.

Effects of Scleral-lens Tear Clearance on Corneal Edema and Post-lens Tear Dynamics: A Pilot Study.

SIGNIFICANCE: The present study with small-diameter scleral lenses (SLs) revealed that post-lens tear thickness (PoLTT) was significantly associated with post-lens tear mixing, but not with central corneal edema, after short-term SL wear. PURPOSE: The aim of this study was to investigate the influence of SL tear clearance (PoLTT) on central corneal thickness and post-lens tear dynamics during 5-hour lens wear. METHODS: Neophytes with no active ocular disease were fitted bilaterally with SLs (hofocon A; 15.6-mm diameter; ~438-µm thickness; 97 Dk; 1.44 refractive index) with various initial PoLTT values ranging from 74 to 543 µm. Central corneal thickness and PoLTT were measured using optical coherence tomography during lens wear. Tear mixing was assessed using fluorogram and "out-in" method. RESULTS: The mean central corneal edema after 5-hour lens wear was 1.51% (95% confidence interval, 1.26 to 1.76%; P < .001), reached its peak at 2-hour post-lens insertion (1.65% [95% confidence interval, 1.45 to 1.85%]), and was independent of PoLTT. The fastest fluorescence decay of the post-lens tear film was observed superiorly. The fluorescence decay rate increased from center to periphery in all quadrants except superiorly. An inverse relationship was found between PoLTT and fluorescence decay rate at both 20-minute and 5-hour wear after lens insertion (P < .05). Excluding observations with out-in time exceeding 5 minutes, we found a direct relationship between PoLTT at 20 minutes after lens insertion and out-in time (P = .047). The % change in the PoLTT after 5-hour wear was greater with a thinner initial tear clearance than those with a thicker one (P = .034). CONCLUSIONS: Within our study parameters, a thinner PoLTT under a small-diameter SL was associated with faster PoLTT mixing. However, there was no relationship between PoLTT and central corneal thickness during 5-hour SL wear.

Síndrome Iridocorneana Endotelial: Relato de Caso da Variante de Chandler / Iridocorneal Endothelial Syndrome: Case Report of Chandler's Variant

Resumo O presente estudo tem por objetivo relatar um raro caso da variante de Chandler da Síndrome Iridocorneana Endotelial em uma paciente de 56 anos. Esta referia baixa acuidade visual em olho direito há 2 anos, acompanhada de fotofobia e prurido. Ao exame oftalmológico, no primeiro atendimento, apresentava em olho direito acuidade visual de conta dedos à 0,5 metro e se observava à biomicroscopia policoria, edema corneano com microcistos e hiperemia conjuntival. O olho esquerdo não apresentava alterações. A pressão intraocular era de 16mmHg no olho direito e 10mmHg no olho esquerdo. Iniciou-se tratamento tópico com dorzolamida, maleato de timolol e dexametasona, sendo então, alcançado o controle da pressão intraocular. Constatou-se no exame de microscopia especular corneana a presença de ice cells. Na biomicroscopia atual, apresenta, no olho acometido, edema corneano com opacidade central, policoria, cristalino não visível e fundo de olho indevassável. Diante da confirmação do diagnóstico de Síndrome de Chandler, pelo quadro clínico compatível e alterações nos exames complementares, a paciente está em acompanhamento no serviço de Oftalmologia do Hospital Federal Servidores do Estado.

Abstract We report in this study a case of Chandler's Syndrome, an Iridocorneal Endhotelial Syndrome variant in a 56 years old patient, female, complaining about low vision in the right side, as well as itching and photophobia in the same side. In the first evaluation, we observed visual acuity of counting fingers at 0,5 meters, corneal swelling with microcystus and conjunctival hyperemia. The left eye was normal. Intraocular pressure was 16mmHg in right eye and 10 mmHg in left eye. We initiated topic treatment with Dorzolamide, Timolol and Dexamethasone, with good control of intraocular pressure. We noticed in corneal specular microscopy the presence of ice cells. In current biomicroscopy it is remarkable the corneal swelling, with central opacity and lens was not visible, as well as the fundoscopy is impossible. We confirmed the diagnosis of Chandler' Syndrome based on the clinical findings, and in abnormalities in complementary exams. Nowadays, the patient is being followed in the Ophthalmology department at Hospital Federal Servidores do Estado.

Non-steroidal anti-inflammatory drugs versus corticosteroids for controlling inflammation after uncomplicated cataract surgery.

BACKGROUND: Cataract is a leading cause of blindness worldwide. Cataract surgery is commonly performed but can result in postoperative inflammation of the eye. Inadequately controlled inflammation increases the risk of complications. Non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids are used to prevent and reduce inflammation following cataract surgery, but these two drug classes work by different mechanisms. Corticosteroids are effective, but NSAIDs may provide an additional benefit to reduce inflammation when given in combination with corticosteroids. A comparison of NSAIDs to corticosteroids alone or combination therapy with these two anti-inflammatory agents will help to determine the role of NSAIDs in controlling inflammation after routine cataract surgery. OBJECTIVES: To evaluate the comparative effectiveness of topical NSAIDs (alone or in combination with topical corticosteroids) versus topical corticosteroids alone in controlling intraocular inflammation after uncomplicated phacoemulsification. To assess postoperative best-corrected visual acuity (BCVA), patient-reported discomfort, symptoms, or complications (such as elevation of IOP), and cost-effectiveness with the use of postoperative NSAIDs or corticosteroids. SEARCH METHODS: To identify studies relevant to this review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Trials Register (2016, Issue 12), MEDLINE Ovid (1946 to December 2016), Embase Ovid (1947 to 16 December 2016), PubMed (1948 to December 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 16 December 2016), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com; last searched 17 June 2013), ClinicalTrials.gov (www.clinicaltrials.gov; searched December 2016), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en; searched December 2016). SELECTION CRITERIA: We included randomized controlled trials (RCTs) in which participants were undergoing phacoemulsification for uncomplicated cataract extraction. We included both trials in which topical NSAIDs were compared with topical corticosteroids and trials in which combination therapy (topical NSAIDs and corticosteroids) was compared with topical corticosteroids alone. The primary outcomes for this review were inflammation and best-corrected visual acuity (BCVA). DATA COLLECTION AND ANALYSIS: Two review authors independently screened the full-text articles, extracted data from included trials, and assessed included trials for risk of bias according to Cochrane standards. The two review authors resolved any disagreements by discussion. We graded the certainty of the evidence using GRADE. MAIN RESULTS: This review included 48 RCTs conducted in 17 different countries and two ongoing studies. Ten included studies had a trial registry record. Fifteen studies compared an NSAID with a corticosteroid alone, and 19 studies compared a combination of an NSAID plus a corticosteroid with a corticosteroid alone. Fourteen other studies had more than two study arms. Overall, we judged the studies to be at unclear risk of bias. NSAIDs alone versus corticosteroids aloneNone of the included studies reported postoperative intraocular inflammation in terms of cells and flare as a dichotomous variable. Inflammation was reported as a continuous variable in seven studies. There was moderate-certainty evidence of no difference in mean cell value in the participants receiving an NSAID compared with the participants receiving a corticosteroid (mean difference (MD) -0.60, 95% confidence interval (CI) -2.19 to 0.99), and there was low-certainty evidence that the mean flare value was lower in the group receiving NSAIDs (MD -13.74, 95% CI -21.45 to -6.04). Only one study reported on corneal edema at one week postoperatively and there was uncertainty as to whether the risk of edema was higher or lower in the group that received NSAIDs (risk ratio (RR) 0.77, 95% CI 0.26 to 2.29). No included studies reported BCVA as a dichotomous outcome and no study reported time to cessation of treatment. None of the included studies reported the proportion of eyes with cystoid macular edema (CME) at one week postoperatively. Based on four RCTs that reported CME at one month, we found low-certainty evidence that participants treated with an NSAID alone had a lower risk of developing CME compared with those treated with a corticosteroid alone (RR 0.26, 95% CI 0.17 to 0.41). No studies reported on other adverse events or economic outcomes. NSAIDs plus corticosteroids versus corticosteroids aloneNo study described intraocular inflammation in terms of cells and flare as a dichotomous variable and there was not enough continuous data for anterior chamber cell and flare to perform a meta-analysis. One study reported presence of corneal edema at various times. Postoperative treatment with neither a combination treatment with a NSAID plus corticosteroid or with corticosteroid alone was favored (RR 1.07, 95% CI 0.98 to 1.16). We judged this study to have high risk of reporting bias, and the certainty of the evidence was downgraded to moderate. No included study reported the proportion of participants with BCVA better than 20/40 at one week postoperatively or reported time to cessation of treatment. Only one included study reported on the presence of CME at one week after surgery and one study reported on CME at two weeks after surgery. After combining findings from these two studies, we estimated with low-certainty evidence that there was a lower risk of CME in the group that received NSAIDs plus corticosteroids (RR 0.17, 95% CI 0.03 to 0.97). Seven RCTs reported the proportion of participants with CME at one month postoperatively; however there was low-certainty evidence of a lower risk of CME in participants receiving an NSAID plus a corticosteroid compared with those receiving a corticosteroid alone (RR 0.50, 95% CI 0.23 to 1.06). The few adverse events reported were due to phacoemulsification rather than the eye drops. AUTHORS' CONCLUSIONS: We found insufficient evidence from this review to inform practice for treatment of postoperative inflammation after uncomplicated phacoemulsification. Based on the RCTs included in this review, we could not conclude the equivalence or superiority of NSAIDs with or without corticosteroids versus corticosteroids alone. There may be some risk reduction of CME in the NSAID-alone group and the combination of NSAID plus corticosteroid group. Future RCTs on these interventions should standardize the type of medication used, dosing, and treatment regimen; data should be collected and presented using the Standardization of Uveitis Nomenclature (SUN) outcome measures so that dichotomous outcomes can be analyzed.

Interpreting the corneal response to oxygen: Is there a basis for re-evaluating data from gas-goggle studies?

When anoxia (0% oxygen) is created within a gas-tight goggle, ocular physiological responses, including corneal swelling, limbal hyperaemia and pH change, are known to vary, depending on the presence or absence of a low, oxygen transmissibility contact lens. A new theory is proposed to account for this discrepancy based on the concept of lid derived oxygen, whereby oxygen originating from the vascular plexus of the palpebral conjunctiva supplements that available to the ocular surface in an open, normally blinking eye, even when the surrounding gaseous atmosphere is anoxic. The effect of a lid derived contribution to corneal oxygenation was assessed by using existing experimental data to model open-eye, corneal swelling behavior as a function of atmospheric oxygen content, both with and without the presence of a contact lens. These models predict that under atmospheric anoxia, contact lens wear results in 13.2% corneal swelling compared with only 5.4% when the lens was absent. Lid derived oxygen acts to provide the ocular surface in the non-contact lens wearing, normally blinking, open-eye with up to 4.7% equivalent oxygen concentration, even within the anoxic environment of a nitrogen filled goggle. Correcting for lid derived oxygen eliminates previously observed discrepancies in corneal swelling behavior and harmonizes the models for the contact lens wearing and gas-goggle cases. On this basis it is proposed that true anoxia at the ocular surface cannot be achieved by atmospheric manipulation (i.e. a gas-goggle) alone but requires an additional presence, e.g. a low, oxygen transmissibility contact lens, to prevent access to oxygen from the eyelids. Data from previously conducted experiments in which the gas-goggle paradigm was used, may have been founded on underestimates of the real oxygen concentration acting on the ocular surface at the time and if so, will require re-interpretation. Future work in this area should consider if a correction for lid derived oxygen is necessary.

Scleral contact lenses in the management of pellucid marginal degeneration.

PURPOSE: To assess visual improvement with scleral lenses (PROSE, prosthetic replacement of the ocular surface ecosystem, Boston Foundation for Sightight, USA) in patients with Pellucid marginal degeneration (PMD). METHODS: This is a single-center, retrospective case-series involving patients with clinical PMD who underwent scleral lens-PROSE trial for improvement of visual acuity, from January 2009 to December 2012 at a tertiary center in India. Scleral lenses with different front surface eccentricities (FSE) were tried for improvement of visual acuity. Snellen visual acuity before and with PROSE wear was noted. Complications with PROSE wear to follow-up were noted. RESULTS: PROSE was dispensed to 12 patients (20 eyes) out of 19 patients having PMD. Location of PMD was inferior in fourteen and superior in two eyes. Four eyes had co-existing keratoconus. Nine were males and three were females. The indications for scleral lens were lens popping-out, failure of piggy-back contact lens and RGP failure. LogMAR Visual acuity improved significantly from 0.45±0.31 pre-PROSE to 0.05±0.08 post-PROSE (p=0.0001). The FSE ordered was 0.6 in 17 eyes, 0.3 in one eye and 0.8 in two eyes. Three patients had hydrops over follow-up; two patients underwent keratoplasty and one was managed conservatively with steroids and hyperosmotic agents. Seven patients did not order PROSE: reasons were - no perceived improvement in visual acuity (n=2), wanted to decide (n=2), continued glasses (n=1) and continued RGP contact lens (n=1). One patient had difficulty with self lens insertion. CONCLUSION: PROSE improves visual acuity in PMD; three patients developed hydrops over follow-up.

Dietary restriction mitigates age-related accumulation of DNA damage, but not all changes in mouse corneal epithelium.

The cornea protects the anterior eye and accounts for two thirds of the eyes refractive capacity. The homeostasis of corneal epithelium is thought to be maintained by putative stem cells residing in the epithelial basal layer. As a tissue constantly exposed to environmental stress, the cornea is hypothesised to accumulate persistent DNA damage events with time in stem cell populations. Recently, telomere associated DNA damage foci (TAFs) have been suggested as a marker for persistent DNA damage which can be used to detect senescent cells during ageing. Dietary restriction (DR) is the only known non-genetic intervention that is able to increase both life and health span among various animal species. The aim of this study was to analyse changes in corneal properties with age and under 16 months of DR. We employed immunofluorescence staining for ɣH2A.X together with telomere fluorescence in situ hybridisation (immuno-FISH) on mouse corneas from young, old ad libitum (AL) fed as well as dietary restricted (DR) mice. Our data show that the central corneas of old mice had significantly more general and telomere-associated DNA damage compared to young mice while DR treatment was able to reduce the amount of DNA damage significantly. We also found that the thickness of the peripheral region of the cornea, where the putative stem cells may reside, decreased with age regardless of whether the animals underwent DR treatment or not. Number of bullae, which indicates corneal edema, accumulated in old corneas in the central area and DR treatment mitigated the formation of these bullae. Moreover, the protein levels of the stem cell marker TAp63 decreased with age only in the central but not the peripheral region of the cornea. This finding suggests that epithelial progenitors might be better maintained in the peripheral than the central cornea during ageing. Together with the finding that the peripheral corneal showed no increase in DNA damage during age, we speculate that in mice, like humans, the putative stem cells reside in the peripheral cornea.

O papel da membrana de Descemet na patogenia do edema corneano após cirurgia de segmento anterior / The role of Descemet's membrane in the pathogeny of corneal edema following anterior segment surgery

Objetivo: Encontrar fatores importantes na patogenia do edema corneano pós-cirúrgico, em casos de pós-facectomia e pósceratoplastia, por meio do estudo dos achados histopatológicos, a fim de ver o que pode ser feito para evitar sucessivas ceratoplastias. Métodos: Estudo retrospectivo descritivo das alterações histopatológicas de casos de edema corneano pós-cirúrgicos. Os tecidos foram provenientes de ceratoplastia penetrante no período compreendido entre setembro de 2009 e agosto de 2013. Foi realizada revisão de prontuários em busca principalmente de informações sobre cirurgias prévias. Resultados: Foram incluídos 70 botões corneanos, sendo 34 de pacientes do sexo masculino e 36 do sexo feminino. A média das idades foi de 63,1±17,20 (média ± DP) anos. A maioria dos casos era de falência após transplante (71,43%). A rarefação celular foi a principal alteração encontrada no endotélio (58 casos), sendo também a alteração histopatológica mais frequente. Na membrana de Descemet, predominaram as alterações de integridade (53 casos), seja na forma de ruptura, de descolamento isolado ou de descolamento associado à ruptura. Foi frequente a associação de alterações endoteliais à ausência da integridade da membrana de Descemet. Conclusão: Descolamento da membrana de Descemet é um achado histopatológico frequente nos casos de edema corneano pós-cirúrgicos estudados, devendo ser considerado um fator importante na patogenia dos mesmos. Essa alteração deve ser procurada com atenção nos pós-operatórios, a fim de ser diagnosticada e tratada precocemente, vindo possivelmente a evitar muitas indicações de ceratoplastia. .

Objective: To find relevant factors in the pathogeny of postoperative corneal edema in post-cataract surgery and post-keratoplasty cases, through the study of histopathological findings in order to see what can be done to avoid successive keratoplasties. Methods: Retrospective descriptive study of histopathological findings in postoperative corneal edema cases. Tissues were obtained from penetrating keratoplasty in the period between september 2009 and august 2013. A medical record review was conducted primarily looking for information about previous surgeries. Results: Seventy corneal buttons were included, out of which 34 were from male patients and 36 were from female patients. The mean age was 63.1±17.20 (mean ± SD) years. Most of cases were corneal failure after keratoplasty (71.43%). The main change found in endothelium was cellular rarefaction (58 cases), and it was also the most common histopathological change. Changes in integrity predominated in Descemet's membrane (53 cases), whether in the form of rupture, isolated detachment or detachment associated with rupture. Endothelial changes associated with the absence in Descemet's membrane integrity were frequent. Conclusion: Descemet's membrane detachment is a frequent histopathological finding in postoperative corneal edema cases studied, thus it should be considered an important factor in the pathogeny of such cases. This change should be carefully researched in the postoperative period in order to be diagnosed and treated early, possibly avoiding many keratoplasty indications. .

Effect of femtosecond laser-assisted cataract surgery on the corneal endothelium.

PURPOSE: To compare the effect on the corneal endothelium of femtosecond laser-assisted cataract surgery and conventional phacoemulsification cataract surgery. SETTING: Private clinic, Tasmania, Australia. DESIGN: Prospective comparative cohort study. METHODS: Femtosecond laser-assisted cataract surgery (study group) or conventional phacoemulsification (control group) was performed. The central corneal thickness, central 3.0 mm corneal volume, volume stress index, and central endothelial cell density (ECD) were measured preoperatively and 1 day, 3 weeks, and 6 months postoperatively. RESULTS: The study group comprised 405 eyes and the control group, 215 eyes. Postoperative corneal edema was significantly less in the study group at 1 day and 3 weeks. However, the difference was negligible at 6 months. The study group had significant reductions in ECD loss compared with the control group [corrected] at 3 weeks but not at 6 months (6-month mean -150 cells/mm(2) ± 244 [SD] versus -149 cells/mm(2) ± 233). Eyes in the study group with laser-automated corneal incisions had greater endothelial cell loss at 6 months than eyes in the study group with manual corneal incisions and eyes in the control group (P<.0001). Eyes in the study group with zero effective phaco time and manually created corneal incisions had statistically significantly less endothelial cell loss at 6 months than the other groups (P<.0001). CONCLUSIONS: Femtosecond laser pretreatment for cataract surgery was associated with a significant reduction in early postoperative corneal edema and endothelial cell loss compared with conventional phacoemulsification; however, the difference diminished with time. Laser-automated corneal incisions seemed to adversely affect the corneal endothelial cells. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Corneal changes following short-term miniscleral contact lens wear.

PURPOSE: To examine the influence of short-term miniscleral contact lens wear on corneal shape, thickness and anterior surface aberrations. METHODS: Scheimpflug imaging was captured before, immediately following and 3h after a short period (3h) of miniscleral contact lens wear for 10 young (mean 27±5 years), healthy participants. Natural diurnal variations were considered by measuring baseline diurnal changes obtained on a separate control day without contact lens wear. RESULTS: Small but significant anterior corneal flattening was observed immediately following lens removal (overall mean 0.02±0.03mm, p<0.001) which returned to baseline levels 3h after lens removal. During the 3h recovery period significant corneal thinning (-13.4±10.5µm) and posterior surface flattening (0.03±0.02mm) were also observed (both p<0.01). The magnitude of posterior corneal flattening during recovery correlated with the amount of corneal thinning (r=0.69, p=0.03). Central corneal clearance (maximum tear reservoir depth) was not associated with corneal swelling following lens removal (r=-0.24, p>0.05). An increase in lower-order corneal astigmatism Z(2,2) was also observed following lens wear (mean -0.144±0.075µm, p=0.02). CONCLUSIONS: Flattening of the anterior corneal surface was observed immediately following lens wear, while 'rebound' thinning and flattening of the posterior surface was evident following the recovery period. Modern miniscleral contact lenses that vault the cornea may slightly influence corneal shape and power but do not induce clinically significant corneal oedema during short-term wear.

Endoteliopatía por amantadina / Endoteliopathy by amantadine

Caso clínico. Mujer de 42 años en tratamiento con amantadina durante 3 años por enfermedad de Parkinson, que presentó edema corneal bilateral. El caso se orientó como una endotelitis herpética que no mejoró tras el tratamiento. Se desconocía la medicación utilizada por la paciente. Tras la suspensión de la amantadina el edema corneal se resolvió aunque el recuento endotelial permaneció bajo. Discusión. La amantadina afecta al endotelio corneal. Origina un edema corneal normalmente reversible aunque la densidad endotelial permanece baja. Se hace conveniente la exploración oftalmológica antes de iniciar un tratamiento con amantadina para valorar el riesgo/ beneficio del mismo (AU)

Case report. A 42 year-old female with Parkinson disease treated with amantadine for three years who presented with bilateral corneal oedema. It was initially labelled as herpetic endothelitis without improvement with treatment. We lacked information on her treatment. After drug withdrawal the corneal oedema ?nally resolved. Nevertheless, the endothelial count remained low. Discussion. Amantadine affects corneal endothelium. It causes corneal oedema, usually reversible. Nevertheless, endothelial density remains low. An ophthalmologist examination should be performed before the initiation of treatment in order to establish a risk/bene?t ratio (AU)

Corneal oedema and its medical treatment.

Corneal oedema is a common sign of acute or protracted corneal disease of various aetiologies. In this paper, we review the causes and pathophysiological bases of corneal oedema, as well as discussing the goals and modalities of its medical treatment. Corneal oedema, if adequately understood and appropriately treated, generally shows a good prognosis.

Central corneal thickness considered an index of corneal hydration of the UVB irradiated rabbit cornea as influenced by UVB absorber.

UVB radiation from sunlight induces an acute corneal inflammation, photokeratitis, accompanied by changes in corneal hydration. We employed a method of ultrasonic pachymetry for daily examination of central corneal thickness as an index of corneal hydration of the rabbit cornea repeatedly irradiated by UVB radiation (312 nm, daily dose of 0.25 J/cm(2) during three or four days) as influenced by UVB absorber (actinoquinol combined with hyaluronic acid) dropped on the ocular surface during irradiation. One day after the third irradiation procedure the animals were sacrificed and corneas examined immuno-histochemically for peroxynitrite formation, a marker of oxidative damage, the antioxidant aldehyde dehydrogenase 3A1 and endothelial nitric oxide synthase, an enzyme generated nitric oxide. Results show that UV absorber combined with hyaluronic acid protected the cornea against UVB-induced changes in corneal thickness and microscopical disturbances to the cornea (both seen after buffered saline application) until the fourth experimental day. These UVB doses are equivalent to a daily exposure of 2.5 hrs of the human cornea to solar UVB radiation for three consecutive days. It is suggested that actinoquinol/ hyaluronic acid drops might be helpful for the human eye in the defence against photooxidative and other oxidative processes.

Modulation of central corneal thickness by various riboflavin eyedrop compositions in porcine corneas.

PURPOSE: To evaluate the modulatory effect of various riboflavin 0.1% and 0.2% compositions on the central corneal thickness (CCT) in fresh porcine corneas. SETTING: Department of Ophthalmology, Johannes Gutenberg University of Mainz, Mainz, Germany. DESIGN: Experimental study. METHODS: The CCT in freshly enucleated porcine globes was measured by ultrasound pachymetry before and after (if applicable) deepithelialization and every 10 minutes thereafter during 120 minutes of eyedrop application. In Groups 1 and 2 (controls), no eyedrops were applied. In Groups 3 and 4, isotonic riboflavin eyedrops were used. In Groups 5 to 9, hypotonic riboflavin eyedrops were given. In Groups 10 and 11, preparations for transepithelial crosslinking were applied. In Groups 2 to 9, deepithelialization was performed. The final CCT in the groups was compared by analysis of variance. RESULTS: One hundred ten freshly enucleated porcine globes were used. The mean final CCT compared with preoperative values was 97% ± 4% (SD) in Group 1, 91% ± 4% in Group 2, 66% ± 5% in Group 3, 151% ± 13% in Group 4, 65% ± 2% in Group 5, 105% ± 3% in Group 6, 120% ± 4% in Group 7, 130% ± 4% in Group 8, 132% ± 4% in Group 9, 114% ± 2% in Group 10, and 114% ± 4% in Group 11. The differences between Group 1 and each of Groups 3, 4, 5, 7, 8, and 9 were statistically significant (P<.05). CONCLUSION: There was considerable variation in the final CCT as a result of varying riboflavin eyedrop compositions. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Intraoperative performance and postoperative outcome comparison of longitudinal, torsional, and transversal phacoemulsification machines.

PURPOSE: To compare the intraoperative performance and postoperative outcomes of 3 phacoemulsification machines that use different modes. SETTING: Kensington Eye Institute, Toronto, Ontario, Canada. DESIGN: Comparative case series. METHODS: This chart and video review comprised consecutive eligible patients who had phacoemulsification by the same surgeon using a Whitestar Signature Ellips-FX (transversal), Infiniti-Ozil-IP (torsional), or Stellaris (longitudinal) machine. RESULTS: The review included 98 patients. Baseline characteristics in the groups were similar; the mean nuclear sclerosis grade was 2.0 ± 0.8. There were no significant intraoperative complications. The torsional machine averaged less phacoemulsification needle time (83 ± 33 seconds) than the transversal (99 ± 40 seconds; P=.21) or longitudinal (110 ± 45 seconds; P=.02) machines; the difference was accentuated in cases with high-grade nuclear sclerosis. The torsional machine had less chatter and better followability than the transversal or longitudinal machines (P<.001). The torsional and longitudinal machines had better anterior chamber stability than the transversal machine (P<.001). Postoperatively, the torsional machine yielded less central corneal edema than the transversal (P<.001) and longitudinal (P=.04) machines, corresponding to a smaller increase in mean corneal thickness (torsional 5%, transversal 10%, longitudinal 12%; P=.04). Also, the torsional machine had better 1-day postoperative visual acuities (P<.001). CONCLUSIONS: All 3 phacoemulsification machines were effective with no significant intraoperative complications. The torsional machine outperformed the transversal and longitudinal machines, with a lower mean needle time, less chatter, and improved followability. This corresponded to less corneal edema 1 day postoperatively and better visual acuity.