About

Steven Greenstein is a Clinical Assistant Professor at Rutgers New Jersey Medical School within the Department of Ophthalmology & Visual Science. The page does not provide specific details about his research focus, background, or key contributions.

Research topics

• Internal medicine
• Ophthalmology
• Surgery
• Medicine

Selected publications

• Refining Progressions and Tasks: A Case Study of Design Cycles to Support Covariational Reasoning

  Journal of Research in Science Mathematics and Technology Education · 2024-11-25 · 1 citations

  articleOpen accessSenior author

  Design-based research is a common tool mathematics educators use to study student learning and to generate high-level learning progressions and sequences of concrete mathematical tasks through iterative research cycles. There is a need for more transparent accounts of how researchers make decisions during the generation of such progressions and tasks. We address this need by describing the results of a case study of our design decisions, leveraging the constructs of local instruction theories and hypothetical learning trajectories to frame our decisions to promote students’ quantitative and covariational reasoning. We describe four considerations that influenced our re-design both of mathematical tasks and of learning progressions to support students’ covariational reasoning across seven teaching cycles with middle school students in the U.S. (ages 12-14). The four considerations that repeatedly influenced our task design decisions between cycles are: 1) supporting student thinking towards our goals, 2) eliciting student thinking, 3) keeping instruction efficient, and 4) exploring new possibilities. We discuss the importance of these considerations in our own work. We also highlight ways this work informs research on students’ quantitative and covariational reasoning and provide implications for task design. Through this report, we intend to provide an account that examines the task design process with reflexivity in a way that is useful for other researchers.

  PublisherDOI

• Application of sentiment and word frequency analysis of physician review sites to evaluate refractive surgery care

  Advances in Ophthalmology Practice and Research · 2024-03-07 · 6 citations

  articleOpen accessSenior authorCorresponding

  Background: Online physician reviews increase transparency in health care, helping patients make informed decisions about their provider. Language processing techniques can quantify this data and allow providers to better understand patients' experiences, perspectives, and priorities. The objective of this study was to assess patient satisfaction and understand the aspects of care that are valued by patients seeking refractive care using sentiment and word frequency analysis. Methods: Written reviews and Star ratings for members of the Refractive Surgery Alliance Society practicing in the United States were collected from Healthgrades, a popular physician rating website. Surgeons with at least one written review were included in the study. Reviews were scored from -1 (most negative) to +1 (most positive) using Valence Aware Dictionary sEntiment Reasoner (VADER). Reviews were stratified by demographic characteristics, namely gender, region, and years in practice. Word frequency analysis was applied to find the most common words and phrases. Results: ​= ​0.07). "Staff" (n ​= ​1269), "professional" (n ​= ​631), "office" (n ​= ​523), "questions" (n ​= ​424), and "friendly" (n ​= ​386) were frequently used in reviews, along with phrases such as "the staff" (n ​= ​273) and "my questions" (n ​= ​174). "Surgery" (n ​= ​719), "staff" (n ​= ​576), "procedure" (n ​= ​251), "experience" (n ​= ​243), and "professional" (n ​= ​240) were the most common words in positive reviews, while "surgery" (n ​= ​147), "office" (n ​= ​86), "staff" (n ​= ​54), "time" (n ​= ​47), and "insurance" (n ​= ​28) were the most commonly used in negative reviews. Conclusions: Both the average Stars and VADER sentiment score suggest a high satisfaction among refractive patients. Word frequency analysis revealed that patients value non-clinical aspects of care, including interactions with staff, insurance coverage, and wait-times, suggesting that improving non-clinical factors could enhance patient satisfaction with refractive surgery.

  PublisherDOI

• Prevalence of Keratoconus Based on Scheimpflug Corneal Tomography Metrics in a Pediatric Population From a Chicago-Based School Age Vision Clinic

  Eye & Contact Lens Science & Clinical Practice · 2024-02-07 · 13 citations

  article

  PURPOSE: Determine the pediatric prevalence of keratoconus (KC) using Scheimpflug corneal tomography. METHODS: A prospective observational study was done on subjects aged 3 to 18 years at the Princeton Vision Clinic, Chicago, IL. Scheimpflug tomography (Pentacam HR, OCULUS Optikgerate GmbH) scans (Belin/Ambrósio Enhanced Ectasia BAD3) yielded BAD Final D (Final D) and Back Elevation at the Thinnest Point (BETP) measurements. Criteria differentiating non-KC from KC suspects & KC were, Non-KC -Final D <2.00 in both eyes; KC suspect -Final D ≥2.00 and <3.00 in combination with BETP ≥18 μm for myopia and ≥28 μm for hyperopia/mixed astigmatism in at least one eye; and KC -Final D of ≥3.00 with BETP ≥18 μm for myopia or ≥28 μm for hyperopia/mixed astigmatism in at least one eye. Two thousand two hundred and six subjects were recorded, removing duplicate and poor-quality scans leaving 2007 subjects. RESULTS: Of 2007 subjects, six were classified as KC -prevalence of 1:334, three subjects were KC suspects -prevalence of 1:669, and total prevalence of KC suspects and KC was 1:223. CONCLUSION: The prevalence of KC in children is higher than previously reported, emphasizing the importance of sensitive screening for KC at its earliest manifestation as standard in pediatric comprehensive eye examinations.

  PublisherDOI

• Update on corneal crosslinking for keratoconus and corneal ectasia

  Current Opinion in Ophthalmology · 2024-04-30 · 8 citations

  article1st author

  PURPOSE OF REVIEW: To review corneal crosslinking for keratoconus and corneal ectasia, and recent developments in the field. This study will review the mechanism of crosslinking, clinical approaches, current results, and potential future innovations. RECENT FINDINGS: Corneal crosslinking for keratoconus was first approved by U.S. FDA in 2016. Recent studies have confirmed the general long-term efficacy of the procedure in decreasing progression of keratoconus and corneal ectasia. New types of crosslinking protocols, such as transepithelial treatments, are under investigation. In addition, adjunctive procedures have been developed to improve corneal contour and visual function in these patients. SUMMARY: Crosslinking has been found to be well tolerated and effective with the goal of decreasing progression of ectatic corneal diseases, keratoconus and corneal ectasia after refractive surgery. Studies have shown its long-term efficacy. New techniques of crosslinking and adjunctive procedures may further improve treatments and results.

  PublisherDOI

• Corneal tissue addition keratoplasty: new intrastromal inlay procedure for keratoconus using femtosecond laser–shaped preserved corneal tissue

  Journal of Cataract & Refractive Surgery · 2023-03-21 · 20 citations

  article1st authorCorresponding

  PURPOSE: To report results of Corneal Tissue Addition Keratoplasty (CTAK) for keratoconus (KC) and ectasia after laser in situ keratomileusis. SETTING: Cornea and refractive surgery practice. DESIGN: Single center, prospective, open label clinical trial. METHODS: 21 eyes of 18 patients underwent CTAK. A tissue inlay of preserved corneal tissue was cut to customized specifications with a femtosecond laser and placed in a laser-created channel in the host cornea. Postoperative uncorrected and corrected distance visual acuity (UDVA, CDVA), manifest refraction spherical equivalent (MRSE), topographic mean keratometry (Kmean), maximum keratometry (Kmax), and the point of maximum flattening (Kmaxflat) were measured. RESULTS: Average UDVA improved from 1.21 ± 0.35 logMAR lines (LL) (20/327) to 0.61 ± 0.25 LL (20/82) ( P < .001). Average CDVA improved from 0.62 ± 0.33 LL (20/82) to 0.34 ± 0.21 LL (20/43) ( P = .002), and average MRSE improved from -6.25 ± 5.45 diopters (D) to -1.61 ± 3.33 D ( P = .002). Individually, 20 eyes (95.2%) gained more than 2 lines of UDVA, with 10 eyes (47.6%) gaining more than 6 lines, and no eyes worsening. 12 eyes (57.1%) gained at least 2 lines of CDVA, with 1 eye worsening by more than 2 lines. At 6 months, average Kmean flattened by -8.44 D ( P = .002), Kmax flattened by -6.91 D ( P = .096), and mean Kmaxflat was -16.03 D. CONCLUSIONS: CTAK is a promising procedure to improve visual acuity and topography in patients with KC and ectasia.

  PublisherDOI

• EQIP Quality Assessment of Refractive Surgery Resources on YouTube

  Seminars in Ophthalmology · 2023-05-03 · 10 citations

  articleSenior authorCorresponding

  Purpose To evaluate the utility of EQIP as a novel tool for determining the quality of patient information on YouTube regarding refractive eye surgery.Methods Three searches were conducted on YouTube using “PRK eye surgery”, “LASIK eye surgery”, and “SMILE eye surgery”. 110 relevant videos were evaluated using the Ensuring Quality Information for Patients (EQIP) criteria.Results The average EQIP score was 15.1 (moderate quality). On average, physician-authored videos scored significantly higher on questions 17 (p = .01), 18 (p = .001), 26 (p = .008), relating to author transparency and use of graphs/figures. Patient-authored videos scored significantly higher on questions 8 (p < .001), 9 (p < .001), 12 (p = .008), 16 (p = .02), and 21 (p = .0350). These questions addressed risks/benefits, quality of life and alert signs, date and video revisions, and personally addressing viewers.Conclusion EQIP was useful in identifying specific strengths and deficits in online refractive surgery patient education resources that were not evident from other screening tools. The quality of information on YouTube videos on refractive surgeries is average. Physician-authored videos could be improved by clarifying risks and quality of life issues. Quality evaluation of medical information is important for comprehensive online surgical education.

  PublisherDOI

• Less Complex Contact Lens Required for a Patient With Keratoconus After Topography-Guided Photorefractive Keratectomy

  Eye & Contact Lens Science & Clinical Practice · 2023-08-25

  articleSenior authorCorresponding

  ABSTRACT: In this report, we discuss contact lens (CL) fitting in a patient with a history of keratoconus (KC), before and after undergoing topography-guided photorefractive keratectomy (TG PRK). Before TG PRK, the patient failed multiple CL modalities and reported difficulty with his habitual CLs and inadequate spectacle-corrected visual acuity to perform his activities of daily living. In this case, a collaborative, comprehensive approach to visual management in a patient with KC was used, and after TG PRK was performed to improve his corneal contour and symmetry, our patient was fit with a standard soft CL and additionally had improved spectacle-corrected visual acuity.

  PublisherDOI

• Topography-Guided Photorefractive Keratectomy After Intacs Corneal Implantation for Keratoconus and Ectasia

  Journal of Refractive Surgery Case Reports · 2023-04-01

  articleOpen accessSenior author

  Purpose: To evaluate outcomes of topography-guided photorefractive keratectomy (TG-PRK) after Intacs (Addition Technology) implantation for eyes with keratoconus or ectasia. Methods: Three eyes of 3 patients with keratoconus or ectasia after laser in situ keratomileusis were treated with TG-PRK 6 months after simultaneous Intacs implantation and standard corneal cross-linking (CXL) was performed. Results: After Intacs implantation/CXL, uncorrected distance visual acuity improved four lines in 1 eye and did not change significantly in the other eyes. At 1 year of follow-up after TG-PRK, uncorrected distance visual acuity further improved more than two lines in all eyes. After Intacs implantation/CXL, corrected distance visual acuity did not change significantly in all eyes. One year after TG-PRK, corrected distance visual acuity improved more than two lines in all eyes. After both procedures, the inferior-superior value decreased and maximum keratometry flattened significantly in all eyes. The change in thinnest pachymetry was less than 32 µm. Conclusions: TG-PRK appears promising as a treatment modality to improve visual acuity and corneal topography in patients with keratoconus and ectasia with prior Intacs placement who may have previously required segment explantation after poor refractive outcomes. [ Journal of Refractive Surgery Case Reports. 2023;3(2):e10–e13.]

  PublisherOA PDFDOI

• Long-Term Outcomes After Corneal Cross-linking for Progressive Keratoconus and Corneal Ectasia: A 10-Year Follow-Up of the Pivotal Study

  Eye & Contact Lens Science & Clinical Practice · 2023-08-08 · 13 citations

  article1st authorCorresponding

  OBJECTIVES: To report on the topographic and visual outcomes 10 years after corneal cross-linking in patients with progressive keratoconus and corneal ectasia after refractive surgery. METHODS: Cross-sectional cohort study of an original, prospective, randomized, clinical trial. Patients treated in a single center cornea and refractive surgery practice as part of the U.S. pivotal trials, which led to the Food and Drug Administration approval of corneal cross-linking, were recruited for a 10-year follow-up examination. LogMar lines (LL) of uncorrected visual acuity (UCVA) and best spectacle--corrected visual acuity (BSCVA), maximum keratometry, and thinnest pachymetry were evaluated. In addition, the Belin ABCD progression display was used to determine progression (95% confidence interval) of the anterior curvature, posterior curvature, and corneal thickness of each individual eye included. RESULTS: Nineteen eyes of 13 patients treated with standard cross-linking returned for a 10-year follow-up examination. Mean maximum keratometry changed from 58.2±12.0 diopters (D) to 58.3±10.1 D, thinnest pachymetry changed from 440.6±51.6 µm to 442.3±54.4 μm, UCVA changed from 0.79±0.42 LL to 0.86±0.46 LL, and BSCVA changed from 0.38±0.26 LL to 0.33±0.34 LL, 10 years after cross-linking. Individually, 68.5% of the entire cohort, 81.8% of keratoconus eyes, and 50% of eyes with corneal ectasia remained topographically stable 10 years after standard cross-linking. CONCLUSIONS: In the entire cohort, visual acuity and topography remained stable 10 years after cross-linking. Over the long-term, eyes with keratoconus seem to be more stable than those with corneal ectasia.

  PublisherDOI

• Correlation of Manifest Refraction and Simulated Keratometry to Tomography Characteristics in Patients With Keratoconus

  Eye & Contact Lens Science & Clinical Practice · 2023-08-28 · 1 citations

  article1st authorCorresponding

  OBJECTIVES: To report on baseline refractive and keratometric values and their correlation with tomographic characteristics of eyes with keratoconus (KC). METHODS: Retrospective chart review of patients treated in a single-center cornea and refractive surgery practice. Baseline topographic measurements were reviewed for 1,012 keratoconic eyes of 586 patients between 2008 and 2018. The manifest refraction, thinnest pachymetry (P thin ), corneal astigmatism (K astig ), and the maximum (K max ), steep (K steep ), flat (K flat ), and mean (K mean ) keratometry were analyzed. The location of K max (x, y) was used to determine central (<1 mm), paracentral (1-3 mm), pericentral (3-5 mm), or peripheral (>5 mm) cone locations. RESULTS: In the entire cohort, the mean manifest sphere was -2.2±4.4 diopters (D) and the cylinder was -3.2±2.3 D. In total, 48.6% of patients had against the rule (ATR) manifest astigmatism (M astig ). The average K astig was 3.8±2.7 D, and unlike the manifest axis, 50.2% of patients had with the rule (WTR) K astig . Patients with a K max less than 50 D had an M astig of -1.9±1.6 D, 45.9% of which was ATR M astig . With respect to baseline tomography measurements, K max , K steep , K flat , and K mean were 58.0±9.4, 50.6±6.5, 46.8±5.9, and 48.6±6.1 D, respectively. There was a weak correlation between K max and simulated keratometry (K steep , K flat , and K mean ) for patients with a K max less than 60 D. CONCLUSIONS: Simulated keratometry is poorly correlated with KC severity until the disease is more severe. M astig ≥2 D and ATR M astig were correlated with KC at all levels of severity. M astig ≥2 D and ATR M astig may serve as a simple, inexpensive, and widely available indicator for topographic analysis to identify possible KC and suggest further workup; however, further prospective studies are needed to confirm its utility.

  PublisherDOI

Recent grants

• Prospective Elementary Teachers Making for Mathematical Learning

  NSF · $422k · 2018–2021

Frequent coauthors

• Peter S. Hersh

  208 shared

• John D. Gelles

  Rutgers, The State University of New Jersey

  77 shared

• K. L. Fry

  Cornea and Laser Eye Institute - Hersh Vision Group

  50 shared

• Austin S. Yu

  30 shared

• Daniel C. Chung

  23 shared

• Becky Su

  19 shared

• Victoria Vought

  Rutgers New Jersey Medical School

  12 shared

• Rita Vought

  Rutgers, The State University of New Jersey

  12 shared