Rohit Krishna

Should all patients with candidaemia have an ophthalmic examination to rule out ocular candidiasis

Purpose To determine the incidence of ocular candidiasis and length of ophthalmic follow-up required to rule out ocular candidiasis in candidaemic patients.Methods We prospectively studied patients with candidaemia at our institution. Eligibility criteria included a dilated ophthalmological examination within 72 h of fungaemia. Patients without ocular candidiasis on initial examination had follow-up dilated ophthalmoscopy performed at 1, 2, 4, 12 and 24 weeks.Results Between May 1996 and March 1997 a total of 50 patients with fungaemia were identified of whom 31 were included in the study; 15 excluded patients died before an initial examination was performed. The overall incidence of ocular candidiasis was 26% (8/31 patients), all manifested as chorioretinitis. Five patients (16%) had ocular candidiasis on their initial examination. One of 21 patients (5%) without ocular candidiasis on initial examination developed ocular candidiasis within 1 week. Two of 16 patients (13%) without ocular candidiasis on initial examination or at 1 week follow-up developed ocular candidiasis within 2 weeks. No evidence of ocular candidiasis occurred in the 12 patients with follow-up at 4 weeks, the 8 patients with follow-up at 12 weeks and the 4 patients with follow-up at 24 weeks.Conclusion The incidence of ocular candidiasis among hospitalised patients is clinically significant. We recommend ophthalmological follow-up for development of ocular candidiasis for at least 2 weeks after an initial negative eye examination.

Resident cataract surgical training in United States residency programs.

&NA; A comprehensive survey was sent to the residency directors of 129 ophthalmology training programs in the United States. Forty percent of residents gained experience as primary surgeon during their first year; 43% performed only part of the surgery. Seventy‐three percent began learning cataract extraction using the extracapsular cataract extraction (ECCE) technique, 24% began with phacoemulsification, and 2% began with either method. If beginning with ECCE, 18% must have completed more than 10 before moving to phacoemulsification, 37% more than 5, and 45% more than 1. Seventy‐five percent learned various phacoemulsification techniques; 25% learned only 1 technique. If beginning with 1 technique, 44% began with the scleral tunnel combined with divide and conquer. Sixty‐four percent learned phacoemulsification on the Alcon Legacy, 21% on the Alcon Legacy and Storz Millennium, and 6% on the Storz Millennium. Sixty‐eight percent of residents rotated out of their main facility to perform cataract surgery. The mean and median number of cataract procedures a resident completed by the end of training was 113 and 100, respectively.

Implantation of Second Glaucoma Drainage Devices After Failure of Primary Devices

BACKGROUND AND OBJECTIVE To evaluate the efficacy and safety of implantation of a second glaucoma drainage device for eyes that have failed a primary device. PATIENTS AND METHODS Medical records of patients receiving a primary glaucoma drainage device at Bascom Palmer Eye Institute from January 1987 to October 1998 were reviewed, of which 18 eyes of 18 patients were studied. Patients failing a primary glaucoma drainage procedure and receiving a second glaucoma drainage device were included in this study. The second eye in the same patient was excluded if a second drainage implant was required. All patients received a second device in a standardized fashion with the drainage tube inserted in the anterior chamber. Main outcome measures included: visual acuity, intraocular pressure (IOP), antiglaucomatous medication, length of follow up, and surface area of glaucoma drainage device. Success was defined as an IOP less than or equal to 21 mm Hg with or without medications, and at least a 20% reduction in IOP, without the need for additional glaucoma procedures. RESULTS The mean postoperative IOP (19.6 +/- 9.4 mm Hg; range, 8-50 mm Hg) was significantly (P = 0.006) lower than the mean preoperative IOP (29.5 +/- 8.1 mm Hg; range, 20-52 mm Hg) at last follow up (mean 19.6 +/- 13.6 months; range, 6-47 months). The mean number of postoperative antiglaucomatous medications (2.2 +/- 1.2; range 0-4) was statistically similar (P = 0.2) to mean preoperative number of antiglaucomatous medications (2.6 +/- 1.2, range 1-4). Using Kaplan-Meier estimates, successful IOP reduction was observed in 89%, 83%, 63%, and 37% of eyes at 6 months, 1, 2, and 3 years, respectively. Four patients (21%) had a decline in visual acuity. CONCLUSIONS Implantation of secondary glaucoma drainage devices may be useful in eyes that have failed primary devices.

Resident glaucoma surgical training in United States residency programs.

Purpose:To determine current trends in resident glaucoma surgical training throughout the United States. Methods:A comprehensive survey was sent to the residency director of all 121 ACGME-accredited ophthalmology training programs in the United States. Results:The mean and median number of glaucoma procedures a resident will complete by the end of their training is 8.6 and 8 respectively for trabeculectomy, 5.3 and 4 for combined trabeculectomy/phacoemulsification, and 3.6 and 2 for tube-shunts. One percent of residents will gain experience as primary surgeon on trabeculectomies during their first year, 32% during their second year, and 67% during their third year. Seventy-five percent of residents are taught more than one trabeculectomy technique by more than one staff surgeon. Eighty-four percent of residents are taught glaucoma surgery almost exclusively by fellowship-trained glaucoma surgeons. Eighty-two percent of residents use antimetabolites (mitomycin C or 5-FU) as an adjunct to trabeculectomy most or all of the time. More than 96% of resident tube-shunt procedures use Ahmed, Baerveldt, or Molteno devices. Eighty percent of residents do not perform any pediatric glaucoma surgeries. Sixty-two percent of residents rotate out of their main facility to perform glaucoma surgery. Conclusions:Residents are being exposed to glaucoma surgery early in their residency training. Most are performing a variety of different procedures and techniques, and are taught by fellowship-trained surgeons. Residents gain very little exposure to pediatric glaucoma surgery. All programs reported compliance with minimum RRC requirements for glaucoma filtering surgery.

Resident laser in situ keratomileusis surgical training in United States residency programs

&NA; To determine current trends in resident laser in situ keratomileusis (LASIK) training in the United States, a comprehensive survey was sent to the residency coordinator, chairman, or refractive surgery director of all 113 ophthalmology training programs in the U.S. accredited by the Accreditation Council for Graduate Medical Education. The response rate was 64%. Of the respondents, 54% were from programs in which residents performed LASIK surgery, typically as third‐year residents; residents in these programs performed a mean of 4 LASIK surgeries (range 1 to 10 surgeries) during residency. The Visx Star was the most commonly used excimer laser platform and the Hansatome the most commonly used microkeratome. Most programs had 1 attending physician teaching the residents refractive surgery, which was typically performed at the main residency facility. Most programs had significant discounted pricing (>50%) for resident‐performed LASIK.

Post-mortem iris biometric analysis in Sus scrofa domesticus

Although biometric utility of ante-mortem human iris tissue has been long established, post-mortem study of human iris tissue for its biometric utility has only been speculated. Given obstacles in measuring and analyzing biometric capability of post-mortem human iris tissue, an investigation into the feasibility of using post-mortem Sus scrofa domesticus iris tissue as a biometric is undertaken. The contributions of our work are two-fold: first, our method discusses a feasible alternative to human iris for study of post-mortem iris biometric analysis. Second, we report the performance of iris biometrics over a period of time after death. Previous studies have only reported qualitative changes in iris after death while for the first time we measure the biometric capacity of post-mortem iris tissue.

Surgical management of a dysfunctional filtering bleb.

This case report presents a patient who developed a large overhanging bleb following antimetabolite trabeculectomy surgery 6 years prior. Complaints included decreasing vision and foreign body sensation for several months. Successful excisional surgery with placement of compression sutures was performed. Visual acuity and intraocular pressure were maintained with the resolution of symptoms.

A comparative analysis of wavelets for vascular similarity measurement

Vascular Similarly Measurement (VSM) is an important tool in many biomedical applications. However, designing a robust computational VSM remains a challenge. We investigate different wavelet families and their orders to find their efficacy as feature extractors for computational VSM. Using a 50-subject dataset of RGB ocular surface vasculature images, we show that a compact feature vector composed of wavelet packet energies derived from Db1 wavelets, in conjunction with Fisher linear discriminant analysis and judged by the ensuing ROCs, is best suited for this task. Coif1 and Rbio2.4 were found to be the next best two wavelets for this purpose. Repetition of the same experiments using neural networks confirmed the optimality of the above suite of features for VSM.

Evaluation of tensile strength of tissue adhesives and sutures for clear corneal incisions using porcine and bovine eyes, with a novel standardized testing platform

Background Tissue adhesives for ophthalmologic applications were proposed almost 50 years ago, yet to date no adequate tissue glues have been identified that combine strong sealing properties with adequate safety and absence of postsurgical side effects. In recent years, cataract surgeries and Descemet’s stripping with endothelial keratoplasty procedures have significantly increased the number of clear corneal incisions performed. One of the obstacles to discovery and development of novel tissue adhesives has been the result of nonstandardized testing of potential tissue glues. Methods We developed an instrument capable of controlling intraocular pressure in explanted porcine and bovine eyes in order to evaluate sealants, adhesives, and surgical closure methods used in ophthalmic surgery in a controlled, repeatable, and validated fashion. We herein developed and validated our instrument by testing the adhesive properties of cyanoacrylate glue in both porcine and bovine explant eyes. Results The instrument applied and maintained intraocular pressure through a broad range of physiological intraocular pressures. Cyanoacrylate-based glues showed significantly enhanced sealing properties of clear corneal incisions compared with sutured wounds. Conclusion This study shows the feasibility of our instrument for reliable and standardized testing of tissue adhesive for ophthalmological surgery.

Comparing the efficacy of the monocular trial treatment paradigm with multiple measurements of intraocular pressure before and after treatment initiation in primary open-angle glaucoma

The monocular trial has been proposed as a test to help control for diurnal fluctuations in eye pressure when assessing medication effectiveness. We undertook a prospective study to determine the sensitivity and specificity of the monocular trial as a test for determining the effectiveness of a glaucoma medication. The efficacy of the monocular trial was compared to the diagnostic paradigm of repeated pre- and post-treatment measurements in determining whether an intraocular pressure (IOP)-lowering drug is effective. Forty-two patients with newly diagnosed open-angle glaucoma completed five visits: visit 1 for determining eligibility, obtaining consent, and measuring IOP, visit 2 for a second pressure measurement, and visit 3 for a third pressure reading. The new medication was then started in one eye. IOP measurements were made at weeks 4 and 6. The gold standard IOP change was defined as the difference in mean between the pre- and post-medication visits. A medication was deemed effective if this difference was at least 15%. The monocular trial pressure change was defined as the IOP change in the treated eye between the visit immediately before and immediately after the medication addition, corrected by subtracting the pressure change in the untreated eye. All 42 patients completed the full protocol with good compliance. Twenty-five of 42 (60%) medication additions were considered effective by the gold standard method, and 25/42 (60%) by the monocular trial method. However, the two methods agreed in only 26 patients (17 Yes/Yes, 9 No/No). The calculated sensitivity was low (0.68), with a specificity of 0.53. The monocular trial can give useful clues as to whether a medication is effective, but should not be the only information used in making this determination. To obtain the most valid results, multiple pressure checks should be done before and after starting a new medication.