Christopher T. Leffler

Interpretation of uniocular and binocular trials of glaucoma medications: an observational case series

BackgroundTo predict the effectiveness of topical glaucoma medications based on initial uniocular and binocular treatment. To test a traditional hypothesis that effectiveness following a uniocular trial is associated with the change in IOP in the initially treated eye minus the change in the initially untreated eye. To determine whether uniocular or binocular treatment trials are superior.MethodsBased on a review of medical records, we identified 168 instances in 154 patients with bilateral primary open angle glaucoma of initial uniocular use of a topical glaucoma medication with well-documented intraocular pressure (IOP) readings at baseline (IOPA), during the trial (IOPB), and at follow-up (IOPC). Abstracted data included demographic data, IOP, and medication use. Predictors of the IOP following the trial (IOPC) in each eye were identified by multivariable linear regression. In 70 cases, the predictive ability of initial uniocular and binocular treatment could be directly compared.ResultsIn a multivariable analysis, the follow-up pressure in the initially treated eye (IOP1C) was directly correlated with treated eye IOP during initial uniocular use (IOP1B, p < 0.001). In a multivariable analysis, the follow-up pressure in the initially untreated eye (IOP2C) was directly correlated with its baseline IOP2A (p < 0.001), and also tended to be associated with treated IOP1B (p = 0.07). The multivariable regression coefficient (b) for the IOP change in the initially untreated eye was generally not close to the value of -1 expected by the classic teaching (for eye 1, b = 0.04, p = 0.35; for eye 2, b = 0.07, p = 0.50). In 70 cases, the uniocular and binocular trials predicted a similar fraction of the variance in follow-up IOP1C (r2 = 0.56 and 0.57, respectively) and IOP2C (r2 = 0.39 and 0.38, respectively).Conclusion1) For uniocular trials, the IOP change in the untreated eye should not be subtracted from that in the treated eye. 2) Uniocular and binocular trials have similar predictive value when interpreted correctly. Either may be selected based on clinical circumstances.

Evolution and Impact of Eye and Vision Terms in Written English

With this article, we aimed to trace the evolution and impact of eye-related terms common in written English during the past 2 centuries by studying digital resources. Eye-related words and phrases (n-grams) occurring in English books at a frequency of 0.00001% for at least 25 years between 1790 and 2008 were identified from the Google n-gram database by searching for 254 strings such as eye or ophth. The first known English use of these n-grams was identified from historical articles and from multiple digital resources. Eye color was not commonly described as brown or green before 1840. Many common bigrams, such as bright eyes, suggested light emanating from the eyes, consistent with the extramission theory of vision. Based on word frequency, the impact of the revolutionary 1850 ophthalmoscope exceeded that of the stethoscope for 60 years. Glaucoma was not commonly written until the ophthalmoscope permitted visualization of the characteristic optic neuropathy. Green spectacles gave way during the early 1900s to dark glasses, subsequently renamed sunglasses. Until the mid-1900s, an eye surgeon was more often described as an oculist than an ophthalmologist, and inflamed eyes were said to experience ophthalmia more often than uveitis. Macular degeneration was rarely written about for more than a century after 1850 because it was labeled choroiditis. Of the 135 n-grams in the dictionary, an earlier written instance was identified in 92 cases (68%). Online databases of the written word reveal the origin and impact of many important vision concepts.

The early history of glaucoma: the glaucous eye (800 BC to 1050 AD)

To the ancient Greeks, glaukos occasionally described diseased eyes, but more typically described healthy irides, which were glaucous (light blue, gray, or green). During the Hippocratic period, a pathologic glaukos pupil indicated a media opacity that was not dark. Although not emphasized by present-day ophthalmologists, the pupil in acute angle closure may appear somewhat green, as the mid-dilated pupil exposes the cataractous lens. The ancient Greeks would probably have described a (normal) green iris or (diseased) green pupil as glaukos. During the early Common Era, eye pain, a glaucous hue, pupil irregularities, and absence of light perception indicated a poor prognosis with couching. Galen associated the glaucous hue with a large, anterior, or hard crystalline lens. Medieval Arabic authors translated glaukos as zarqaa, which also commonly described light irides. Ibn Sina (otherwise known as Avicenna) wrote that the zarqaa hue could occur due to anterior prominence of the lens and could occur in an acquired manner. The disease defined by the glaucous pupil in antiquity is ultimately indeterminate, as the complete syndrome of acute angle closure was not described. Nonetheless, it is intriguing that the glaucous pupil connoted a poor prognosis, and came to be associated with a large, anterior, or hard crystalline lens.

Preoperative iris configuration and intraocular pressure after cataract surgery

PURPOSE: To determine predictors of long‐term intraocular pressure (IOP) after cataract surgery. SETTING: Hunter Holmes McGuire Veterans Administration Hospital, Richmond, Virginia, USA. DESIGN: Case series. METHODS: Clinical variables, IOP by applanation tonometry, anatomic features on anterior segment optical coherence tomography (AS‐OCT), and gonioscopy were assessed before and after uneventful cataract surgery in eyes with open filtration angles. Multivariate linear regression of preoperative measurements was used to predict the mean IOP from 2 to 18 months postoperatively. RESULTS: The study enrolled 77 eyes (77 patients). Prediction of the mean postoperative IOP improved when up to 4 preoperative IOP values were averaged (r2 = 0.20) compared with using the final preoperative IOP value only (r2 = 0.13). The mean iris cross‐sectional area decreased after surgery, from 3.84 mm2 to 3.70 mm2 (P=.01). The mean convex hull of the iris segments also decreased, from 5.05 mm2 to 4.19 mm2 (P<.001). The mean postoperative IOP was independently predicted by the preoperative average IOP, primary open‐angle glaucoma, and the convex hull of cross‐sectional iris segments (P=.001, model r2 = 0.38) or iris cross‐sectional area (P=.003, model r2 = 0.36). Phacoemulsification parameters, incision type, and anterior chamber angle and depth did not predict postoperative IOP. CONCLUSIONS: Averaging up to 4 preoperative IOP values improved postoperative IOP predictions. A high iris cross‐sectional area or convex hull of the iris segments on AS‐OCT was associated with lower postoperative IOP. These findings might help identify patients who are likely to have the largest IOP drop after cataract surgery. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Prediction of postoperative astigmatism in cataract surgery.

BACKGROUND The purpose of this study was to predict postoperative astigmatism using refraction, keratometry, and other preoperative information after phacoemulsification with posterior chamber intraocular lens (IOL) implantation. METHODS A retrospective study was conducted of 176 eyes of 161 patients undergoing phacoemulsification for visually significant cataract with capsular bag or sulcus IOL fixation at the Hunter Holmes McGuire Veterans Administration Medical Center, Richmond, Va. Eyes with complications and final-corrected visual acuity of less than 20/60 were excluded. Keratometric and refractive astigmatism were described by Jackson cross-cylinder with-the-rule (J0) and oblique (J45) components. Preoperative predictors of postoperative refractive J0 and J45 were determined by univariate and multivariate regression analysis. RESULTS The final multivariate model to predict postoperative with-the-rule astigmatism was J0Postoperative = 0.24 x J0Preoperative 0.46 x J0Keratometric (-0.08 )(coefficient of determination [r2] = 0.51, all p < 0.001). The multivariate model based on expected predictors of oblique astigmatism was J45Postoperative = 0.10 x J45Preoperative + 0.23 x J45Keratometric + 0.01, (r2 = 0.05, p = 0.09 for J45Preoperative and 0.03 for J45Keratometric). Temporal clear cornea (as opposed to superior scleral tunnel) incisions, and use of sutures in scleral tunnel incisions, were not predictive of postoperative astigmatism. INTERPRETATION Postoperative astigmatism can be estimated from preoperative astigmatism using the following weighted average: two-thirds keratometric and one-third refractive astigmatism. Preoperative refraction may predict postoperative astigmatism independent of keratometry because keratometry reflects only the paracentral anterior (not posterior) corneal curvature.

Clinical predictors of the optimal spectacle correction for comfort performing desktop tasks

Background:  The best strategy for spectacle correction of presbyopia for near tasks has not been determined.

Prevalence and factors predictive of intraocular fungal infection in patients with fungemia at an academic urban tertiary care center

Objective To report the prevalence and to identify factors predictive of intraocular infection in patients with fungemia receiving prophylactic antifungal therapy. Methods A retrospective review of patients who received prophylactic antifungal therapy and a dilated fundus examination at an academic urban tertiary care center from 2000 to 2007. Basic demographic information, fungal species grown, antifungal agent(s) used, number of positive blood culture specimens, visual acuity, visual symptoms, and known risks of disseminated candidiasis were noted. Logistic regression analysis was used to determine the factors significantly associated with intraocular fungal infection. Results A total of 132 patients with positive fungemia culture were requested to have ophthalmology consults. The prevalence of ocular infection was 6.9% (N=9). All nine patients were infected with Candida species. Undergoing gastrointestinal (GI) surgery within the prior 6 months was significantly related to developing intraocular infection, with an odds ratio of 18.5 (95% confidence interval, 15.1–24.3; P=0.002). Having ≥3 positive fungal blood cultures was also a significant risk factor, with an odds ratio of 2.6 (95% confidence interval, 1.8–3.7; P=0.03). Among 40 patients having GI surgery, eight (20.0%) had intraocular fungal disease, compared with one of 92 patients (1.1%) not having GI surgery. Among 125 patients with a negative baseline examination result, two of 32 patients (6.3%), who had recent GI surgery, subsequently developed fungal ocular disease, compared with 0 of 93 patients (0%), who did not have recent GI surgery. Conclusion Recent GI surgery and higher numbers of positive fungal blood culture specimens may be predictive of candida ocular infections. Normal baseline fundoscopy examination results in patients with such risks may require repeat evaluations to detect delayed manifestations.

Congenital Cataract Surgery During the Early Enlightenment Period and the Stepkins Oculists

From antiquity through the Renaissance, congenital blindness was generally regarded as incurable, as noted in both medical and lay publications. The earliest reference to congenital cataract surgery that we identified, reported in 1663, referred to an 18-year-old female treated by English oculist John Stepkins (d. 1652). An examination of the literature related to the Stepkins family reveals the presence of male and female oculists during that period, including his daughter, Lady Theodosia Ivy. Eye waters attributed to Stepkins contained tutty (an oxide of zinc), roses, sugar candy, and other ingredients. Interestingly, John Thomas Woolhouse, the author of the next identified report of congenital cataract surgery in 1706, stated that he was related to Stepkins. Woolhouse reported by 1721 that he had performed 36 congenital cataract surgeries, with the youngest patient being 18 months of age.

Management of hyphema in patients with sickle cell disease or trait

We read the recent review of hyphema by Bansal and colleagues. Some standard recommendations for patients with sickle cell disease or trait go beyond what the available evidence can support. Specifically, Table 3 of the review recommends surgical intervention “In sickle cell trait or sickle cell disease, hyphemas of any size and IOP [intraocular pressure] >24 mm Hg for more than 24 hours” in accord with standard texts. We believe that it is difficult to justify this recommendation in all cases. The authors acknowledge that optic atrophymay develop secondary to traumatic nerve contusion. Thus, many reports of optic atrophymay have been due to the original trauma. It is not easy to find well-documented, peerreviewed reports in which an eye which initially had good vision and pupil responses subsequently suffered optic atrophy with the IOP in the high 20s. The authors add that “patients with sickle cell disease are susceptible to vascular occlusion at relatively low IOPs or relatively brief durations of high pressures.” They support this statement by citing a report in which a young woman with a hyphema and sickle cell trait lost vision when the pressure was 55 mm Hg, but, once the pressure was lowered, regained 20/30 vision with unremarkable fluorescein angiography. Of course, retinal vascular events occur in sickle cell patients at a normal IOP and could doubtless occur at higher pressures as well, but the absolute risk in the absence of a sickle cell crisis or systemic metabolic disturbance is not well defined. The risk of optic nerve damage or vascular events with an IOP in the high 20s must be balanced with the risks of early surgical intervention, which include rebleeding and damage to the crystalline lens. In 1976, Crouch and Frenkel noted that 2 patients with sickle cell trait with traumatic hyphema and an IOP as high as 39 mm Hg for 2 to 4 days sustained “nonglaucomatous optic atrophy.” It is not clear from the report whether the original trauma could have caused the optic atrophy. Crouch later wrote that hyphema patients with sickle cell disease or trait with an IOP of greater than 35mmHg for 24 hours should have surgical washout.

A medieval fallacy: the crystalline lens in the center of the eye

Objective To determine whether, as most modern historians have written, ancient Greco-Roman authors believed the crystalline lens is positioned in the center of the eye. Background Historians have written that statements about cataract couching by Celsus, or perhaps Galen of Pergamon, suggested a centrally located lens. Celsus specifically wrote that a couching needle placed intermediate between the corneal limbus and the lateral canthus enters an empty space, presumed to represent the posterior chamber. Methods Ancient ophthalmic literature was analyzed to understand where these authors believed the crystalline lens was positioned. In order to estimate where Celsus proposed entering the eye during couching, we prospectively measured the distance from the temporal corneal limbus to the lateral canthus in 30 healthy adults. Results Rufus of Ephesus and Galen wrote that the lens is anterior enough to contact the iris. Galen wrote that the lens equator joins other ocular structures at the corneoscleral junction. In 30 subjects, half the distance from the temporal corneal limbus to the lateral canthus was a mean of 4.5 mm (range: 3.3–5.3 mm). Descriptions of couching by Celsus and others are consistent with pars plana entry of the couching needle. Anterior angulation of the needle would permit contact of the needle with the lens. Conclusion Ancient descriptions of anatomy and couching do not establish the microanatomic relationships of the ciliary region with any modern degree of accuracy. Nonetheless, ancient authors, such as Galen and Rufus, clearly understood that the lens is located anteriorly. There is little reason to believe that Celsus or other ancient authors held a variant understanding of the anatomy of a healthy eye. The notion of the central location of the lens seems to have arisen with Arabic authors in 9th century Mesopotamia, and lasted for over 7 centuries.