Sathish Srinivasan

Intraoperative floppy-iris syndrome during cataract surgery in men using alpha-blockers for benign prostatic hypertrophy

A small-pupil syndrome called intraoperative floppy-iris syndrome (IFIS) inmen taking a1A-receptor blockers (namely, tamsulosin hydrochloride) for benign prostatic hypertrophy (BPH) was described by Chang and Campbell in 2005 (D.F. Chang, MD, J.R. Campbell, MD, ‘‘A New Small Pupil Syndrome Caused by Flomax,’’ EyeWorld, January 2005, page 50). This syndrome is characterized by a triad of flaccid iris stroma that causes intraoperative billowing, propensity of the iris to prolapse, and progressive intraoperative miosis. Following Chang and Campbell’s description, there has been increased awareness of this syndrome among cataract surgeons and in the urological literature. The purpose of this study was to assess the occurrence of IFIS during cataract surgery in men on all systemic a-blockers at a university teaching hospital in Toronto, Canada.

Anterior Chamber Gas Bubble Formation During Femtosecond Laser Flap Creation for LASIK

PURPOSE To report anterior chamber gas bubble formation during corneal flap creation in a myopic patient who underwent LASIK using a femtosecond laser (IntraLase). METHODS A 30-year-old man underwent customized wavefront-guided LASIK for myopia. The IntraLase FS15 was used to create the corneal flap. RESULTS During flap creation, gas bubble formation was noted in the anterior chamber, in addition to cavitation bubbles under the flap. Flap creation was successful and myopic ablation was uneventful. One day postoperatively, the flap was well apposed, and no air bubbles were present in the anterior chamber. CONCLUSIONS Gas bubbles in the anterior chamber can be an infrequent occurrence during the use of femtosecond laser for corneal flap creation. Although gas bubbles do not hinder flap creation, their presence may interfere with eye-tracking mechanisms.

Slit-lamp technique of draining interface fluid following Descemet's stripping endothelial keratoplasty.

Aim: To describe a new slit-lamp technique for draining interface fluid to manage complete donor disc detachments following Descemet’s stripping (automated) endothelial keratoplasty (DSEK/DSAEK). Methods: Interventional case series. Five DSEK/DSAEK patients presented on the first postoperative day with complete detachment of the donor lenticule. Slit-lamp biomicroscopy showed interface fluid preventing attachment of the donor disc to the host stromal bed. A new slit-lamp technique is described to drain the interface fluid. This technique involved completely filling the anterior chamber with an air bubble using a 30-gauge needle on a 3 ml syringe. Following this, a 0.12 forceps was used to open the inferior mid-peripheral corneal drainage slit to drain the interface fluid. Results: This technique was successful in draining the interface fluid in all five patients, leading to immediate complete reattachment of the donor disc. Conclusion: Donor disc detachments following DSEK/DSAEK can be successfully managed by this slit-lamp technique of draining the interface fluid.

Endophthalmitis After Penetrating Keratoplasty

PURPOSE To determine the incidence of endophthalmitis after penetrating keratoplasty (PK) and patient and donor risk factors. DESIGN Retrospective cohort study using national transplant registry data. PARTICIPANTS All corneal transplant recipients (n = 11 320) registered on the United Kingdom Transplant Registry undergoing their first PK between April 1999 and December 2006. METHODS Patients who developed endophthalmitis were identified on the transplant registry. In addition, cases where the fellow cornea from the same donor had been transplanted were included. Clinical information regarding donor and recipient characteristics, surgical details, and postoperative outcomes were collected and analyzed. In cases where endophthalmitis was reported, the diagnosis was verified by a follow-up supplementary questionnaire to the surgeon. Logistic regression was used to investigate differences in the factors associated with the development of endophthalmitis. MAIN OUTCOME MEASURES Incidence of endophthalmitis and graft survival. RESULTS The overall incidence of endophthalmitis occurring after primary PK in the UK was 0.67%. The incidence of endophthalmitis occurring within 6 weeks of surgery was 0.16%. Graft survival after endophthalmitis was 27% (95% confidence interval, 16-38) at 5 years, with a mean best-corrected visual acuity of 1.13 (logarithm of the minimum angle of resolution) for surviving grafts. Factors associated with endophthalmitis were donor cause of death (infection), high-risk cases, and indication for corneal transplantation. CONCLUSION Endophthalmitis remains a serious issue, with those affected having reduced graft survival and poor visual outcomes. Management of the identified recipient and donor risk factors are important to reduce endophthalmitis risk. In particular, the increased incidence of endophthalmitis when the donor dies of infection requires further explanation and review of current donor eye retrieval and eye bank practices. The delayed presentation of endophthalmitis cases also raises questions regarding possible sequestration of microbes within the corneal tissue and the effect of antimicrobials in storage media.

Changes in ocular monochromatic higher-order aberrations in the aging eye.

Purpose To characterize corneal, internal, and total ocular monochromatic higher-order aberration (MHOA) changes that occur in the aging eye. Methods Prospective observational case series including 300 eyes of 167 patients (mean age = 63.8 years) attending the ophthalmology service at University Hospital Ayr, Scotland. Corneal, internal, and total ocular aberrations were measured over a 6-mm dilated pupil. Zernike coefficients were obtained to the sixth order. Changes in MHOA between age groups and inter-eye correlations between right and left eyes were analyzed. Results A significant inter-eye correlation was found for refractive mean spherical equivalent and cylinder. A significant inter-eye correlation for the whole eye, corneal, and internal MHOA was found (p < 0.001). Right eye analysis found a significant positive correlation between age and the root mean square of whole eye MHOA (p = 0.012), with an increase from 0.517 &mgr;m in the fifth decade to 0.824 &mgr;m in the ninth. Total internal MHOA increased from 0.411 to 0.704 &mgr;m. A significant positive correlation was found between age and internal fourth- (p = 0.007), fifth- (p = 0.029), and sixth-order (p = 0.025) root mean square aberrations. There were no significant age-related changes in corneal MHOA or corneal spherical aberration. Overall mean (SD) corneal SA was 0.203 (0.082) &mgr;m. Conclusions A strong correlation between the right and left eyes exists for MHOA. Whole eye MHOA increases with age. Such changes can be attributed to age-related changes in the internal optical quality of the eye. Such normative data are useful to the cataract surgeon when considering the use of an aspherical IOL to counteract corneal-induced SA during cataract surgery.

Standard for reporting refractive outcomes of intraocular lens-based refractive surgery

Following the 2014 update to the Graphic Reporting of Outcomes of Refractive Surgery to include vector analysis of astigmatism, the set of 9 standard graphs has provided a detailed 1-page summary for outcomes of corneal laser refractive surgery (laser in situ keratomileusis [LASIK], photorefractive keratectomy, and small-incision lenticule extraction [SMILE]). Until now, the data reporting quality for intraocular lens (IOL) surgery has not benefited from these efforts to enhance and standardize refractive outcomes reporting. For example, a significant number of cataract and lens refractive surgery publications do not include any refractive predictability outcomes, and visual acuity is often reported only as mean values rather than using histogramsda point that was raised in the 2009 editorial. In this editorial, we have considered these issues and have synthesized a solution by making some adjustments to the graphs when reporting IOL surgery outcomes. For phakic IOL outcomes, the original graphs can typically be used without alteration, even though in reality the incision placement likely has some small effect on outcomes. Similarly, these same graphs can be used for refractive lens exchange (RLE); although there are complexities introduced by the corneal incision and removing the natural lens, the presence of a cataractous lens does influence the situation enough to render parts of the analysis inappropriate or unnecessary for a minimum standard. Because the primary indication for cataract surgery is a cataract-related loss of corrected distance visual acuity (CDVA), it remains important to report the surgically induced change in CDVA. However, this

Optical biometry: every little bit helps.

Modern-day cataract surgery has evolved to refractive cataract surgery in which the surgeon can customize and tailor the refractive outcome for each individual patient. Fundamental to this is the accurate measurement of the ocular anatomy to calculate the desired power of the intraocular lens. Before the turn of this century, ultrasound (US) had been the traditional modality used to measure the anterior chamber depth (ACD) and the axial length (AL) of the eye. Contact US has a limited maximum resolution of 0.15 mm. Technological advancement has led to the use of partial coherence interferometry (PCI) as a biometry technique that uses diode laser infrared light at a wavelength of 780 nm. Since the advent of the first commercial device in 2001 (IOLMaster, Carl Zeiss Meditec AG), this has become the technique of choice for ocular biometry. Partial coherence interferometry has become popular as a result of the ease of measurements, its repeatability, and it is a noncontact technique. But more important is its ability to measure AL more accurately to resolutions of approximately 0.02 mm compared with the 0.15 mm obtained with contact US. This is because the laser light source from PCI is reflected from the retinal pigment epithelial layer in contrast to the US waves, which are reflected from the internal limiting membrane. Partial coherence interferometry has also been shown to be consistent and accurate in measuring ocular anatomy and has improved the refractive outcomes after cataract surgery. However, PCI technology for optical biometry measures the AL, corneal curvature, and the horizontal white-to-white distance. The ACD is only indirectly assessed with an imaging technique. Partial coherence interferometry fails to measure in up to 20% of eyes with dense opacities. However, with advanced analysis of the interferencewaveform, this can be reduced to approximately 10%. A new noncontact optical biometer (Lenstar, HaagStreit AG) using optical low-coherence reflectometry (OLCR) was commercially introduced in 2008. The technique was developed in the 1980s in the telecommunication industry for reflection measurements. Fercher et al. were the first to apply this principle to ocularmeasurements.With this new device, a superluminescent diode at 820 nm coupled to the reflectometer is used as a measurement and fixation beam for

Demodex blepharitis mimicking eyelid sebaceous gland carcinoma

prudent to consider both tobacco and alcohol as risk factors to be avoided in carriers of LHON. Pfeiffer et al. recently described five older (>60) patients with LHON who lost vision. They were all male. Dr Grzybowski asks, reasonably, why, if estrogen (partially) protects women before menopause, there is a gender bias after 60. We, like the authors, do not know. Five is a small number, some women take hormonal replacement therapy, and some women maintain estrogen levels after menopause that are still higher than those of men. We agree with Dr. Grzybowski that Osborne et al. have an interesting hypothesis regarding the effects of light on retinal ganglion cells (RGCs) and their axons. They propose that given low ATP levels from genetically impaired mitochondria, reactive oxygen species may induce RGCs to die. However, these and other interesting considerations pertaining to the pathophysiology of LHON were well beyond the scope of our article, which represented a personal tale and related a series of studies that went from bench to bedside and back to the bench in rewarding cycles.

Corneal inlays for spectacle independence: Friend or foe?

Presbyopia is primarily an inevitable, age-related condition that causes irreversible loss of the accommodative amplitude of the eye. Despite its ubiquity, the exact mechanism behind presbyopia remains unclear. Worldwide in 2005, more than 1.04 billion people were estimated to have presbyopia. By the year 2020, the worldwide prevalence is expected to rise to 1.37 billion. The underlying cause for this age-related loss of accommodation has yet to be fully elucidated and continues to remain a topic of controversy.Models for presbyopia are broadly divided into 2 areas and are referred to as lenticular mechanisms and extralenticular mechanisms. Although the lenticular theories propose age-related changes to the lens, capsule, and zonular fibers, the extralenticular mechanism includes ciliary muscle dysfunction, loss of elasticity in the posterior zonular fibers, and even decreased resistance on the vitreous against the lens capsule. Presbyopia affects the quality of life. McDonnell et al. showed that presbyopia was associated with substantial negative effects on health-related quality of life in a population study based in the United States. The safest and least invasive method to treat presbyopia consists of corrective glasses as a separate pair of reading glasses, bifocals, or progressive lenses. Several options to treat presbyopia have been pursued; these include monovision with contact lenses or with laser vision correction, multifocal ablation patterns on the cornea (termed presbyLASIK), and lenticular approaches with refractive lens exchange withmultifocal or extended depth of focus intraocular lenses. One of the earliest approaches for presbyopia correction was additive refractive keratoplasty, in which a foreign material, either biological or synthetic, is added to the corneal tissue to alter the refractive status. Synthetic corneal inlays have been investigated for well over half a century. Barraquer was the first to use them in 1949 for the treatment of aphakia and myopia. The materials used for the synthetic inlays have improved from the early use of flint glass or poly(methyl methacrylate) to hydrogel polymers. The older generation of inlays led to several complications, which included corneal opacification, epithelial and stromal thinning, intracorneal deposits, and decentration. With the developments of newer synthetic materials with improved biocompatibility, better understanding of the wound healing in the cornea, and technological developments with femtosecond laser and stromal pocket creation software, there has been a rekindling of interest in corneal inlays. The current generation of corneal inlays based on the mechanism of action can be divided into 3 categories: small aperture (Kamra, Acufocus, Inc.); shape altering, which do not have intrinsic refractive power but do create a central hyperprolate cornea (Raindrop Near Vision Inlay, Revision Optics, Inc.), and zonal refractive, which provide corneal multifocality (Flexivue Microlens, Presbia Co€ operatief U.A.). Table 1 shows the physical, biomechanical, and functional characteristics of these inlays. All these inlays are implanted in only 1 eyedthe nondominant eyedwith the dominant eye corrected to provide uncorrected distance vision. The benefits of these inlays are that they are potentially reversible, easy to implant, additive, and tissue sparing and one can combine them with other corneal refractive procedures to correct ametropia. The first publication on these new generations of corneal inlays was by Yilmaz et al. in 2008, who reported 1-year data for a small-aperture corneal inlay (ACI-7000, Acufocus, Inc.) in 39 eyes with an uncorrected near visual acuity (UNVA) of Jaeger (J) 3 or better and uncorrected distance visual acuity (UDVA) of 20/40 or better in the eye with the inlay. The long-term follow-up data with the small-aperture corneal inlay showed the UNVA to be J3 or better in 96.9% of eyes at 2 years and in 74.2% of eyes at 5 years. The uncorrected intermediate visual acuity was 20/40 or better in 95% of eyes with the inlay at 2 years and 20/32 or better at 5 years in 87.1% of eyes with the inlay. The UDVA was 20/32 or better in all eyes with the inlay at 2 years and 20/20 or better in 93.5% at 5 years. Between 2006 and 2010, the small-aperture Kamra inlay has undergone design iteration, with the current model (ACI-7000 PDT, Acufocus, Inc.) measuring 6 mm thick with 8400 laser-etched microperforations ranging in size from 6 to 12 mm to allow water, carbon dioxide– oxygen diffusion, and nutrient flow.

Simultaneous correction of aniridia and aphakia.

43.39 G 1.52 D (range 40.45 to 46.72 D). There was no significant relationship between either of these variables and the refractive outcome (PZ.89 and PZ.53, respectively). We agree that capsular distension syndrome cannot occur in the presence of posterior capsule rupture and pointed this out in the manuscript. The references were added to draw attention to this potential confounder if optic capture is used with an intact capsule.dEoghan R.A. Millar, MB ChB, David H.W. Steel, MD, FRCOphth