Risk factors affecting visual outcomes following dropped nucleus after cataract surgery.

BACKGROUND/ AIMS: To describe the visual outcomes in eyes with dropped nucleus during phacoemulsification surgery. SETTING: Singapore National Eye Centre (SNEC). DESIGN: Retrospective chart review of prospectively reported cases of dropped nucleus. METHODS: The clinical charts of all cases of dropped nucleus (Jan 2001 to Dec 2016) were retrospectively reviewed for patient demographics, surgeon type, stage of surgery, timing of pars plana vitrectomy (PPV), and complications. Visual success was defined as best corrected visual acuity (BCVA) ≥ 20/40 at last review. Final risk factors affecting visual success were identified using multivariate logistic regression analysis. RESULTS: Incidence of dropped nucleus following cataract surgery was 0.17% (n = 292). Duration of follow-up was 25.5 months (mean), 18.5 months (median). There was a statistically significant difference in dropped nucleus rate between Residents (0.3%) and Faculty (0.14%) (x2 = 38.2, P < 0.001), but ensuing major complications rates were similar. PPV was performed in 251 eyes (87.2%). At final examination, 202 cases (85.2%) achieved BCVA 20/40 or better, after excluding patients with co-existing ocular pathology. Timing of vitrectomy (delayed vs same-day) did not influence the final visual success (x2 = 0.969, p = 0.51). Risk factors for poor visual outcomes included age >70 years, absence of intraocular lens (IOL) implant, and presence of major complications. CONCLUSION: Overall incidence of dropped nucleus in SNEC was 0.17%, with BCVA of 20/40 or better in 85.2% cases. Visual prognosis was influenced by patient's age, presence of IOL implant or additional major complications.

Endothelial keratoplasty with anterior chamber intraocular lens versus secondary posterior chamber intraocular lens.

AIM: To describe the long-term outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) with an anterior chamber intraocular lens (ACIOL) compared to secondary posterior chamber (PC) IOL. METHODS: This was a retrospective comparative cohort study. The clinical data of 82 eyes from 82 consecutive patients with pseudophakic (PBK) or aphakic bullous keratopathy (ABK) who either underwent DSAEK with retained or secondary ACIOL (n=23) or DSAEK with IOL exchange and/or secondary PCIOL (retropupillary iris-claw IOL, n=25; intrascleral-fixated IOL, n=29; or sulcus IOL, n=5) were analysed. The main outcome measures were graft survival and complications up to 5 years. RESULTS: The graft survival in the secondary PCIOL group was superior than the ACIOL group over 5 years (year 1, 100.0% vs 100.0%; year 3, 94.7% vs 75.0%; year 5, 91.1% vs 60.6%, p=0.022). The presence of an ACIOL was a significant risk factor associated with graft failure (HR, 4.801; 95% CI, 1.406 to 16.396, p=0.012) compared to a secondary PCIOL. There was no significant difference in the rate of graft detachment and elevated intraocular pressure between the groups. There were five cases (9.3%) of IOL subluxation or dislocation in the retropupillary iris-claw and intrascleral-fixated IOL groups. CONCLUSIONS: Eyes that underwent DSAEK with ACIOL in situ had poorer long-term graft survival compared with those with secondary PCIOL. Intraocular lens exchange was not associated with a higher complication rate. In ABK or PBK eyes with ACIOL, we recommend performing IOL exchange and/or secondary PCIOL implantation combined with endothelial keratoplasty.

Management of the subluxated crystalline lens: A review.

Cataract surgery for the subluxated crystalline lens is challenging. A thorough preoperative evaluation is important to determine the appropriate surgical approach for lens removal and the subsequent technique of intraocular lens placement. Important considerations include the extent and location of zonular weakness, and whether the zonular deficiency is caused by a static or progressive disease. The capsular bag should be preserved where possible. Creating a good-sized and centred continuous curvilinear capsulorhexis is crucial to facilitate the use of capsular retractors and capsular tension devices, which provide capsular stability. Nucleus sculpting and rotation should be minimised to reduce zonular stress. Being cognisant of the possible intraoperative complications that may occur at each stage of the surgery and knowing how to reduce the risk of these complications occurring will enable surgeons to perform safe cataract surgery in these complex cases.

Comparison of anterior capsulotomy techniques: continuous curvilinear capsulorhexis, femtosecond laser-assisted capsulotomy and selective laser capsulotomy.

PURPOSE: To compare the anterior capsulotomy edge tear strength created by manual continuous curvilinear capsulorhexis (CCC), femtosecond laser-assisted capsulotomy (FLACS), and selective laser capsulotomy (SLC). SETTING: Singapore National Eye Centre, Singapore and Excel-Lens, Livermore, California, USA. DESIGN: Three armed study in paired human eyes. METHODS: Capsulotomies were performed in 60 cadaver eyes of 30 donors using CCC, Victus Femtosecond Laser, (Bausch & Lomb, Rochester, New York, USA) or CAPSULaser, (Excel-Lens, Los Gatos, California, USA). Three pairwise study groups each involved 10 pairs of eyes. Study group 1: SLC eyes compared with fellow eyes with CCC. Study group 2: CCC eyes compared with fellow eyes with FLACS. Study group 3: FLACS eyes compared with fellow eyes with SLC.A shoe-tree method was used to apply load to the capsulotomy edge, and Instron tensile stress instrument measured distension and threshold load applied to initiate capsule fracture. Relative fracture strengths and distension of CCC, FLACS and SLC were determined. Scanning electron microscopy (SEM) of capsule edges were reviewed RESULTS: Anterior capsulotomies behave as non-linear elastic (elastomeric) systems when exposed to an external load. The pairwise study demonstrated that the SLC fracture strength was superior to that of CCC by a factor of 1.46-fold with SLC 277±38 mN versus CCC with 190±37 mN. Furthermore, CCC fracture strength was superior to that of FLACS by a factor of 1.28-fold with CCC 186 + 37 mN versus FLACS 145 ± 35 mN (p < 0.001). This was determined by statistical analysis utilising the Wilcoxon matched-pairs signed-ranks test and in accordance with the Consolidated Standards of Reporting Trials guidelines. The capsule edge of SLC on SEM demonstrated a rolled over edge anteriorly and an alteration of collagen. CONCLUSIONS: The strength of the capsulotomy edge for SLC was significantly stronger than that of CCC which and both were significantly stronger than FLACS. The relative strengths can be explained by SEM of each type of capsulotomy.

Femtosecond laser-assisted cataract surgery for the white cataract.

AIM: To report the capsulotomy and lens fragmentation outcomes of white cataracts managed with the femtosecond laser (FL). METHODS: Outcomes of a prospective, observational consecutive case series of white cataracts (June 2012-November 2016) that underwent FL-assisted cataract surgery (FLACS) (Victus, Bausch+Lomb, Munich, Germany) at the Singapore National Eye Centre were audited. Data collected: patient demographics, type of white cataract, levelness of docking, anterior capsule position following laser, completeness of capsulotomy and fragmentation, best-corrected visual acuity (BCVA) at 1 month, intraoperative complications. Outcome measures: capsulotomy integrity, fragmentation capability and BCVA at 1 month. RESULTS: 58 eyes of 54 patients underwent FLACS. White cataract types included dry white (24 eyes), intumescent (28 eyes) and Morgagnian (6 eyes). Docking was level in 22 eyes (38.6%). Following FL, the anterior capsule level dropped in 20 eyes (34.5%). Incomplete capsulotomies occurred in 10 eyes (17.2%). Lens fragmentation attempted in 38 eyes was effective or partially effective in 31 eyes (81.6%). No anterior or posterior capsule tears occurred. LogMAR BCVA at 1 month was 0.073 (SD 0.09). Risk factors for incomplete capsulotomy were Morgagnian cataract and lens thickness (multiple logistic regression, p<0.01 and p=0.03, respectively). CONCLUSION: The main complication of FLACS in white cataracts was incomplete capsulotomy (17.2%), significantly associated with Morgagnian cataracts and increased lens thickness. Lens fragmentation was effected in four-fifths of white cataracts but should be avoided in Morgagnian cataracts due to possible overlap of the lens fragmentation plan and the anterior capsule.

Parameters affecting anterior capsulotomy tear strength and distension.

PURPOSE: To study the effects of anterior capsulotomy diameter and discontinuity on tear threshold load and distension for the technique of continuous curvilinear capsulorhexis (CCC). SETTING: Singapore National Eye Centre, Singapore, and CapsuLaser Inc., Livermore, California, USA. DESIGN: Two separate randomized pairwise cadaver eye preclinical studies. METHODS: Capsulotomies were performed in 40 cadaver eyes of 20 donors using CCC. The pairwise comparisons were divided into 2 study groups: Study A: Continuous versus discontinuous capsulotomies; Study B: Capsulotomy diameter of 5.0 mm and smaller versus diameters of 5.2 mm and larger. A shoe-tree method was used to apply load to the capsulotomy rim, and the Instron tensile stress instrument measured threshold load and distension to initiate a capsular tear. Wilcoxon matched-pairs signed-rank tests were performed to assess statistical superiority. RESULTS: In Study Group A, all pairs demonstrated that continuous capsulotomies were better than discontinuous capsulotomies for both the anterior tear threshold load and distension (P < .01). In Study Group B, 80% of the pairs demonstrated that diameters of 5.2 mm and larger were better than those of 5.0 mm and smaller diameter (P < .05). CONCLUSIONS: Anterior capsulotomies behave as nonlinear elastic (elastomeric) systems when exposed to an external load and distension. This study demonstrated that continuous circular capsulotomies were more resistant to anterior tears than discontinuous capsulotomies. A point of irregularity or a defect in a capsulotomy rim has a high probability of being the tear initiation point. Furthermore, larger diameter capsulotomies were more resistant to anterior tears than smaller capsulotomies.

Decision-making and management of uveitic cataract.

The visual outcome of uveitic cataract surgery depends on the underlying uveitic diagnosis, the presence of vision-limiting pathology and perioperative optimization of disease control. A comprehensive preoperative ophthalmic assessment for the presence of concomitant ocular pathology, with particular emphasis on macula and optic nerve involvement, is essential to determine which patients will benefit from improved vision after cataract surgery. Meticulous examination in conjunction with adjunct investigations can help in preoperative surgical planning and in determining the need for combined or staged procedures. The eye should be quiescent for a minimum of 3 months before cataract surgery. Perioperative corticosteroid prophylaxis is important to reduce the risk of cystoid macular edema and recurrence of the uveitis. Antimicrobial prophylaxis may also reduce the risk of reactivation in eyes with infectious uveitis. Uveitic cataracts may be surgically demanding due to the presence of synechiae, membranes, and pupil abnormalities that limit access to the cataract. This can be overcome by manual stretching, multiple sphincterotomies or mechanical dilation with pupil dilation devices. In patients <2 years of age and in eyes where the inflammation is poorly controlled, intraocular lens implantation should be deferred. Intensive local and/or oral steroid prophylaxis should be given postoperatively if indicated. Patients must be monitored closely for disease recurrence, excessive inflammation, raised intraocular pressure, hypotony, and other complications. Complications must be treated aggressively to improve visual rehabilitation. With proper patient selection, improved surgical techniques and optimization of peri- and post-operative care, patients with uveitic cataracts can achieve good visual outcomes.

Clinical outcomes in the first two years of femtosecond laser-assisted cataract surgery.

PURPOSE: To analyze outcomes of femtosecond laser cataract surgery cases in the first 2 years in an ophthalmic institution. DESIGN: Nonrandomized treatment comparison with matched, historical controls. METHODS: Outcomes and intraoperative events of all laser cataract surgeries (5.0- to 5.5-mm-diameter laser capsulotomies and nuclear fragmentation) at the Singapore National Eye Centre (May 2012-December 2013) were prospectively audited. The 6-weeks-postoperative unaided visual acuities (UAVA), mean absolute error (MAE), mean square error (MSE), and manifest refraction spherical equivalent (MRSE) results of surgeons with >50 laser cases were compared with controls, a random sample of manual cases with similar age, axial length, and preoperative cylinders. Statistical analysis was performed with SPSS (P < .05). RESULTS: A total of 1105 eyes (803 patients) underwent laser cataract surgery by 18 surgeons. The majority were female (56.9%) and Chinese (90.9%) with mean age 66.1 ± 11.0 years. Intraoperative complications were subconjunctival hemorrhage (290, 26.2%), anterior capsule tear (9 eyes, 0.81%), posterior capsule rupture (3 eyes, 0.27%), suction loss (5 eyes, 0.45%), iris hemorrhage (1 eye, 0.09%), and endothelial incision (1 eye, 0.09%). There was no dropped nucleus. Visual outcomes of 794 laser surgeries were compared to 420 controls. The %UAVA 20/25 or better was higher in laser cases (68.6% vs 56.3%; P < .0001) but MAE (0.30 ± 0.25 diopter [D] vs 0.33 ± 0.25; P = .062) and MSE (0.16 ± 0.27 D vs 0.17 ± 0.28 D; P = .065) were not significant. MRSE comparison was significant (target plano, preoperative cylinder <1.5 D -0.08 ± 0.36 D vs -0.13 ± 0.40 D; P = .034). CONCLUSIONS: Femtosecond laser cataract surgery has a low complication rate. Cases compared to controls had statistically better %UAVA ≤20/25 and MRSE, although MAE was not significant.

A 5-year audit of cataract surgery outcomes after posterior capsule rupture and risk factors affecting visual acuity.

PURPOSE: To describe the posterior capsule rupture rates and visual outcomes after phacoemulsification, analyze risk factors for poor vision, and compare results of faculty (F) and residents (R). DESIGN: Retrospective audit study. METHODS: Visual success of all capsule ruptures (2006-2010) was analyzed and compared to uneventful cases. Rupture rates of faculty and residents were compared (χ², P < .05). Success was defined as % best-corrected visual acuity (BCVA) ≥20/40 at 3 months (excluding poor-prognosis eyes) and studied in relation to age, sex, surgeon type, stage of surgery, vitreous loss, dropped nucleus, and other complications (eg, retinal detachment, corneal decompensation, dislocated intraocular lens [IOL]). Final risk factors were identified using multivariate logistic regression analysis. RESULTS: From 2006 to 2010, there were 887 capsule ruptures in 48 377 phacoemulsification cases (rate 1.8%). Uneventful cases had significantly better visual outcomes than capsule ruptures (98.5% vs 93.9%; P < .01). Faculty rupture rates were lower (F = 1.4%) than residents' (R = 3.4%; P < .01), but visual outcomes were similar (F = 93.8%, R = 93.7%; P > .05). Ruptures most frequently occurred during phacoemulsification (59.6%) and irrigation and aspiration (24.8%) stages. Risk factors for poor outcomes included age >65 years, dropped nuclei, and other complications. CONCLUSION: The overall capsule rupture rate was 1.8%. Although residents had higher rates, visual success matched faculty's, possibly attributable to case mix and close supervision. Associated risk factors for poor vision included age >65 years, dropped nuclei, and postoperative retinal, corneal, and IOL complications.

Cytomegalovirus-positive corneal stromal edema with keratic precipitates after penetrating keratoplasty: a case-control study.

PURPOSE: To identify differences between cytomegalovirus (CMV)-positive and CMV-negative eyes presenting as suspected endothelial graft rejection after penetrating keratoplasty (PK). METHODS: A retrospective consecutive case-control series. Aqueous humor samples of all eyes with corneal stromal edema and keratic precipitates (KPs) after PK, seen at the Singapore National Eye Centre from 2007 to 2010, were analyzed for CMV DNA by polymerase chain reaction. Their charts were reviewed for demographic data, medical and ocular history, best-corrected visual acuity, intraocular pressure, anterior segment clinical findings, and therapy. RESULTS: Of 11 eligible eyes (11 patients), 7 were CMV positive. All eyes were negative for herpes simplex virus and varicella zoster virus. The 2 groups were similar in age, gender, and previous ocular surgery. The main differences were the presence of extensive heavily pigmented KPs, Descemet membrane folds, and the absence of vascularization of the donor in CMV-positive eyes (100% vs. 0%, P = 0.003, Fisher exact test). All the CMV-positive eyes were treated with ganciclovir (5 systemic, 2 topical), and the control eyes received immunosuppression. However, all the grafts failed. Best-corrected visual acuity at the last visit was worse than 20/400 in all except 1 control eye, which had a follow-up of 30 months. CONCLUSIONS: There is a high prevalence of CMV infection in eyes that develop corneal stromal edema with KPs after PK. Heavy endothelial pigmentation, Descemet membrane folds, and the absence of donor vascularization may aid in the diagnosis of CMV in the event that aqueous analysis is not possible.

Descemet membrane detachment after phacoemulsification surgery: risk factors and success of air bubble tamponade.

PURPOSE: To evaluate the efficacy of air bubble (AB) tamponade for Descemet membrane detachment (DMD) after clear corneal incision phacoemulsification surgery and to evaluate the risk factors for DMD. METHODS: This is a retrospective analysis of patients with DMD managed with AB tamponade, within 42 postoperative days (PODs), over a 4-year period. Data collected were as follows: demographics, cataract density (Lens Opacities Classification System III), visual acuity, AB technique, clinical outcome, and total surgeries over the time period. Successful end points were DM reattachment and corneal clarity. Risk factors were assessed using a case-control study, with univariate and multivariate logistic regression analyses (significance at P < 0.05). RESULTS: Incidence rate of DMD was 0.044% per year. Sixteen patients (mean age of 76 years) had AB tamponade for DMD, with corneal clarity restored in 14 cases (87.5%; n = 11 with 1 AB procedure, n = 3 with 2 AB procedures). The main clear corneal incision was the major site of DMD (n = 14, 87.5%). Pre-AB visual acuity was 20/100 and at 1 month, 20/40. Corneal clarity occurred by 30 days (range: 4-82 days) and remained clear throughout the median follow-up of 12.9 months. Significant univariate factors were as follows: age >65 years, nuclear sclerosis grade ≥4 (Lens Opacities Classification System III), preexisting endothelial disease, and first POD corneal edema. Multivariate logistic regression analyses revealed endothelial disease (odds ratio = 18.66) and first POD edema (odds ratio = 7.88) as significant independent risk factors for DMD occurrence (P < 0.05). CONCLUSIONS: AB tamponade for DMD effectively restored corneal clarity in 87.5% of cases (14 of 16 eyes). Significant risk factors included endothelial disease and first POD corneal edema.

Imaging late capsular bag distension syndrome: an anterior segment optical coherence tomography study.

BACKGROUND: Anterior segment optical coherence tomography (ASOCT) was used to categorize and provide insights into the etiology of capsular bag distension syndrome (CBDS). METHODS: A prospective review was undertaken of 10 cases who presented with signs of late CBDS 5-11 years after uneventful phacoemulsification with in-the-bag posterior chamber intraocular lens implantation. RESULTS: All 10 patients presented with a milky collection within the distended capsular bag without raised intraocular pressure or a shallow anterior chamber. ASOCT was used to confirm the diagnosis in all cases, and a hyperintense signal was seen in the space between the posterior chamber intraocular lens and the posteriorly bowed posterior capsule. The continuous curvilinear capsulorhexis was measured to be between 3.18 mm and 4.70 mm. Three cases had uncorrected visual acuity better than 6/12. Uncomplicated Neodymium-doped Yttrium Aluminium Garnet (Nd:YAG) posterior capsulotomy was performed in eight patients, with no resulting change in the intraocular lens position (measured by ASOCT) or subjective refraction. CONCLUSION: Our study showed that ASOCT is a useful modality to differentiate this condition clearly from posterior chamber intraocular lens opacification and to investigate its causation. Nd:YAG posterior capsulotomy proved to be a safe and successful treatment for late CBDS with no change in biometric or refractive parameters.

Steroid-induced ocular hypertension in Asian children with severe vernal keratoconjunctivitis.

BACKGROUND: We describe clinical characteristics and risk factors for corticosteroid response in children with severe vernal keratoconjunctivitis (VKC). DESIGN: Retrospective, noncontrolled, comparative case series. PARTICIPANTS: Patients from three tertiary centers in Singapore. METHODS: We reviewed patients with severe VKC (clinical grade > 2) who were on topical steroid therapy, with a minimum follow-up period of 1 year post-presentation. Logistic regression was used to determine risk factors for corticosteroid response. MAIN OUTCOME MEASURE: Corticosteroid response was defined as intraocular pressure (IOP) >21 mmHg (three consecutive readings), or a rise of more than 16 mmHg from baseline, after commencement of steroid therapy in the absence of other possible causes of raised IOP. RESULTS: Forty-one of 145 (28.3%) patients developed a corticosteroid response, of which eight (5.5%) progressed to glaucoma. The overall mean age of onset of VKC was 9.9 ± 4.4 years. Longer duration of corticosteroid use (OR, 5.06; 95% CI: 1.04-25.56; P = 0.45) and topical dexamethasone 0.01% (OR, 2.25; 95% CI: 1.99-5.08; P = 0.40) were associated with corticosteroid response. Mixed type of VKC (OR, 9.76; 95% CI: 3.55-26.77; P < 0.001), the presence of limbal neovascularization of ≥ three quadrants (OR, 6.33; 95% CI: 2.36-16.97; P < 0.001), and corneal involvement (OR, 3.51; 95% CI: 1.31-9.41; P = 0.012) were significant clinical risk factors after adjusting for potential confounders such as age, sex, ethnicity, duration, and type of corticosteroid used. CONCLUSION: Children on long-term oral corticosteroids with severe, mixed-type VKC and corneal involvement are more likely to develop corticosteroid response, and may require early treatment to prevent progression to glaucoma.

S100A expression in normal corneal-limbal epithelial cells and ocular surface squamous cell carcinoma tissue.

PURPOSE: To study the expression and cellular distribution of multiple S100A genes and proteins in normal corneal-limbal epithelium and ocular surface squamous cell carcinoma (SCC) tissue. METHODS: Normal corneal-limbal tissue was obtained from the Lions Eye Bank, Tampa, FL. Ocular surface SCC tissues were excised from patients undergoing surgery at Singapore National Eye Centre. S100A mRNA expression was measured by quantitative PCR. S100 protein distribution was determined by immunofluorescent staining analysis. RESULTS: Twelve S100 mRNAs were identified in human corneal and limbal epithelial cells. S100A2, A6, A8, A9, A10, and A11 mRNA was expressed at high level, while S100A1, A3, A4, A5, A6, A7, and A12 mRNA expression was low. The intracellular localization of S100A2, A6, A8, A9, A10 and A11 protein was determined in normal corneal-limbal and SCC tissues. S100A2 and S100A10 proteins were enriched in basal limbal epithelial cells of the normal tissue. S100A8 and S100A9 were found only at the surface of peripheral corneal and limbal epithelium. S100A6 was uniformly found at the plasma membrane of corneal and limbal epithelial cells. S100A11 was found at the supralayer limbal epithelial cells adjacent to the conjunctiva. SCC tissue showed typical pathological changes with expression of cytokeartin (CK) 14 and CK4 in the epithelial cells. All SCC epithelial cells were positive of S100A2, S100A10, S100A6 and S100A11 staining. Intracellular staining of S100A8 and S100A9 was found in several layers of SCC epithelium. Expression of S100A2 and S100A10 decreased dramatically in cultured limbal epithelial cells with increased passaging, which was accompanied by a small increase of S100A9 mRNA, with no changes of S100A8 gene expression. Serum and growth hormone depletion of the culture serum caused a small reduction of S100A2 and S100A10 gene expression, which was accompanied by a small increase of S100A9 mRNA while no changes of S100A8 expression was measured. CONCLUSIONS: Normal corneal and limbal epithelial cells express a broad spectrum of S100 genes and proteins. Ocular surface SCC express high levels of S100A2, S100A10, S100A8 and S100A9 proteins. The expression of S100A2 and S100A10 is associated with limbal epithelial cell proliferation and differentiation.

Anterior segment optical coherence tomography evaluation of the integrity of clear corneal incisions: a comparison between 2.2-mm and 2.65-mm main incisions.

PURPOSE: To compare wound characteristics and integrity of the 2.2-mm and 2.65-mm clear corneal incisions. DESIGN: Prospective, randomized clinical trial. METHODS: Patients undergoing phacoemulsification with lens implant were randomized to receive a 2.2-mm or 2.65-mm temporal clear corneal incision. The incisions were evaluated at 2, 24, and 96 hours for gape and wound architecture using anterior segment optical coherence tomography and for integrity using the Seidel test. Squareness of an incision was calculated (ratio of the incision length to the width). RESULTS: There were 30 patients in each group. Both incision sizes were watertight, although a mild internal main wound gape was detected on anterior segment optical coherence tomography in 35 eyes (58.3%) at 2 hours. The smaller wound was more square (0.81; standard deviation [SD], 0.11) than the larger wound (0.62; SD, 0.08; P < .001, t test). The mean squareness of eyes without wound gape at 2 hours (0.66; SD, 0.11) was lower than those with a wound gape (0.75; SD, 0.14; P = .008). A squareness factor of 0.72 or more had a positive predictive value for presence of wound gape at 2 hours of 79.3% and a negative predictive value of 61.3%. One side port incision with squareness of 1.39 had a mild leak at 2 and 24 hours, but no gape was seen on anterior segment optical coherence tomography. CONCLUSIONS: Both the 2.2-mm and 2.65-mm clear corneal incisions clinically were competent, but the side port incision may leak. A truly square wound has a greater likelihood of being associated with internal wound gape at 2 hours after surgery, especially if the squareness factor is 0.72 or more.

Emerging prevalence of microsporidial keratitis in Singapore: epidemiology, clinical features, and management.

OBJECTIVE: To investigate the incidence and epidemiologic factors involved in the development of microsporidial keratitis. The association of host immune status and clinical pattern, clinical features, and the role of fluoroquinolone monotherapy in treatment are also examined. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: All cases (124 patients, 134 eyes) of microsporidial keratitis confirmed with modified trichrome stain positive of corneal scrape over a 4-year period. METHODS: Epidemiologic factors were observed. Host immune status with human immunodeficiency virus (HIV) serology and CD4/CD8 analysis was performed when consent was obtained. Visual acuity (VA) and slit-lamp examination throughout the course of keratitis was recorded. Treatment used included topical fluoroquinolones (ciprofloxacin 0.3%, moxifloxacin 0.5%, gatifloxacin 0.5%, levofloxacin 0.5%, or norfloxacin 0.3%) as monotherapy or in combination with topical fumagillin and/or systemic albendazole. Where corneal edema developed, ultrasound corneal pachymetry was recorded. MAIN OUTCOME MEASURES: Demographic features and epidemiologic factors, including host immune status. Clinical features and disease course, including the response to different therapeutic regimes. RESULTS: Patients ranged in age from 11 to 68 years (mean, 31.9; median, 30) with a male:female ratio of 8:1 (females n = 17 [13.7%]). We performed HIV serology and CD4/CD8 in 45.9% of cases (n = 57); all the cases tested were negative with normal T-cell indices. Epidemiologic factors included soil exposure (50%), contact lens wear (21.1%), and topical steroid treatment (17.1%). The VA on presentation ranged from 20/20 to 20/100 (median, 20/30) with no loss in lines of VA on resolution. Common features were follicular papillary conjunctivitis and coarse punctate epithelial lesions in 3 patterns--diffuse, peripheral, and paracentral--evolving into nummular keratitis before resolution. Resolution occurred in 99% of cases on topical fluoroquinolone monotherapy. Four patients had recurrent disease that resolved with repeat fluoroquinolone or fluoroquinolone/oral albendazole combination. Two new clinical features were identified--diffuse endotheliitis (19.4%) with corneal edema and limbitis. CONCLUSIONS: This study identifies an increasing incidence of microsporidial keratitis in Singapore with a strong correlation with prior soil exposure. Diffuse endotheliitis and limbitis have not been described and resolves with topical steroid therapy. Topical fluoroquinolone monotherapy is a valid treatment option.

Infectious keratitis after laser epithelial keratomileusis.

PURPOSE: To report two cases of infectious keratitis occurring after laser epithelial keratomileusis (LASEK). METHODS: Two patients who underwent LASEK were referred to our center for the management of postoperative infectious keratitis. Infection occurred on postoperative days 2 (case 1) and 5 (case 2). Presenting visual acuity was count fingers in both cases. RESULTS: Patients were treated aggressively with hourly topical broad-spectrum fortified antibiotics after corneal scrapings were obtained. Culture was positive for Staphylococcus aureus in case 2. Both eyes responded to treatment, resulting in residual corneal scarring with reduced best spectacle-corrected visual acuity of 20/40 in case 1 and uncorrected visual acuity of 20/25 in case 2. CONCLUSIONS: Infectious keratitis can occur after LASEK surgery, and early diagnosis and aggressive therapy are required to aser ereduce visual loss.

Therapeutic keratoplasty for advanced suppurative keratitis.

PURPOSE: To determine indications, therapeutic success, and corneal transplantation techniques for advanced medically uncontrolled infectious keratitis. DESIGN: Retrospective, interventional case series. METHODS: A review of 92 consecutive patients (1991 to 2002) who underwent therapeutic keratoplasty for acute infectious keratitis performed at Singapore National Eye Centre. Causative organism(s) were identified and outcomes were evaluated in terms of infectious cure (therapeutic success), graft clarity, and visual acuity. RESULTS: Pseudomonas aeruginosa (58.7%) and Fusarium species (32.3%) were the predominant organisms for bacterial and fungal keratitis, respectively. Keratoplasty types included penetrating keratoplasty (PK; n = 80) and lamellar keratoplasty (n = 12). Mean graft diameter was 9.5 mm (range, 5.5 to 14 mm). Seventy-four patients (80.4%) achieved therapeutic success after one keratoplasty procedure, three patients were cured after a second keratoplasty. Life-table survival analysis computed the one-year therapeutic survival for bacterial and fungal keratitis as 76.6% and 72.4%, respectively (P = .76). The Kaplan-Meier one-year survival rate for PK optical clarity was 72%. Twenty-two patients underwent repeat keratoplasty for various reasons (optical, n = 8; recurrent primary infection, n = 7; perforation or subsequent new infections, n = 7). Of the 15 patients for whom therapy failed, 11 had fungal keratitis. Infection recurrence time was four days to one year. Most recurrences (n = 11) appeared within six weeks after surgery. CONCLUSIONS: Therapeutic keratoplasty may treat severe, refractory infectious keratitis effectively. High cure rates are achievable, although infection recurrence despite prolonged treatment remains a significant problem in fungal keratitis.