About

Andrew Hartwick OD, PhD, is an Associate Professor in the College of Optometry at Ohio State University. He trained at Dalhousie University in Halifax, Nova Scotia, where he received his Ph.D. in Anatomy & Neurobiology, and at the University of Waterloo in Ontario, where he earned both O.D. and M.Sc. degrees in Vision Science. His research involves both basic laboratory and clinically applied studies, primarily focusing on understanding how a subset of retinal ganglion cells capture light and convert it into electrical signals. He investigates the mechanisms underlying increased light sensitivity often observed after traumatic brain injury. Dr. Hartwick has contributed to numerous studies published in peer-reviewed journals, exploring topics such as pupillary responses to light, circadian rhythms, and neuromodulation of retinal cells, advancing the understanding of visual and neurological responses to light exposure.

Research topics

• Medicine
• Ophthalmology
• Physics
• Psychology
• Optics
• Gastroenterology
• Endocrinology
• Neuroscience
• Surgery
• Materials science
• Internal medicine

Selected publications

• Detection of human herpesvirus 7 in conjunctival samples collected from individuals recovering from conjunctivitis

  Frontiers in Ophthalmology · 2025-08-19

  articleOpen access1st authorCorresponding

  Purpose: Although it is often reported that adenovirus is the most common etiology for infectious conjunctivitis, a recent multi-center clinical study found that adenovirus was confirmed by polymerase chain reaction in only 16% of cases presenting with acute conjunctivitis. Here, we investigated the hypothesis that a member of Herpesviridae could be the underlying etiology in some non-adenoviral cases of conjunctivitis. Methods: Molecular assays for Herpes Simplex 1 and 2 (HSV-1, HSV-2) and Human Herpesvirus 6A, 6B and 7 (HHV-6A, HHV-6B, HHV-7) were performed on conjunctival samples collected from 18 individuals with acute conjunctivitis and during their recovery in follow-up visits that spanned up to 3 weeks. All samples, obtained from individuals enrolled in a clinical trial evaluating a conjunctivitis treatment, were from eyes that had previously tested negative for adenovirus using polymerase chain reaction (PCR) techniques. Results: In total, 160 PCR assays were performed on 40 conjunctival samples. Four of these samples, obtained from four different individuals, tested positive for HHV-7. None of the samples tested positive for HSV-1, HSV-2, HHV-6A or HHV-6B. Conclusion: This data provides further evidence that Human Herpesvirus 7 can be present in the eye, as HHV-7 was detected in a subset of conjunctival samples obtained from individuals recovering from non-adenoviral conjunctivitis. Clinicians should consider non-adenoviral etiologies when managing conjunctivitis that presents as classic 'pink eye'.

  PublisherOA PDFDOI

• Natural history of adenoviral conjunctivitis in a US-based population: Viral load, signs, and symptoms

  Contact Lens and Anterior Eye · 2024-01-03 · 3 citations

  articleOpen access
  PublisherOA PDFDOI

• The association between pupillary responses and axial length in children differs as a function of season

  Scientific Reports · 2024-01-05 · 3 citations

  articleOpen access

  The association between pupillary responses to repeated stimuli and adult refractive error has been previously demonstrated. This study evaluated whether this association exists in children and if it varies by season. Fifty children aged 8-17 years (average: 11.55 ± 2.75 years, 31 females) with refractive error between + 1.51 and - 5.69 diopters (non-cycloplegic) participated (n = 27 in summer, and n = 23 in winter). The RAPDx pupilometer measured pupil sizes while stimuli oscillated between colored light and dark at 0.1 Hz in three sequences: (1) alternating red and blue, (2) red-only, and (3) blue-only. The primary outcome was the difference in pupillary responses between the blue-only and red-only sequences. Pupillary constriction was greater in response to blue light than to red for those with shorter eyes in summer (β = - 9.42, P = 0.034) but not in winter (β = 3.42, P = 0.54). Greater constriction comprised faster pupillary escape following red light onset and slower redilation following stimulus offset of both colors (P = 0.017, 0.036, 0.035 respectively). The association between axial length and children's pupillary responses in summer, but not winter may be explained by greater light-associated release of retinal dopamine in summer. Shorter eyes' more robust responses are consistent with greater light exposure inhibiting axial elongation and reducing myopia risk.

  PublisherOA PDFDOI

• 9.14 Longitudinal assessment of cognition and eye-related symptoms in youth hockey players: the laces youth hockey study

  2024-01-01

  articleSenior author

  <h3>Objective</h3> To determine potential changes in cognitive function over the course of a contact hockey season in asymptomatic youth. <h3>Design</h3> Cohort study, repeated measures. <h3>Setting</h3> Youth hockey ice rink, Bantam (checking) league. <h3>Participants</h3> 13 year old healthy male hockey players (N = 18). <h3>Interventions (or Assessment of Risk Factors)</h3> Data were collected in 3 sessions, each session separated by ~2 months (early-, mid- and late-season). Longitudinal assessments of cognitive function were performed by CogState Computerized Concussion Assessment. <h3>Outcome Measures</h3> Measures of 4 cognitive functions (Processing Speed, Attention, Learning, Memory) as performed by CogState. <h3>Main Results</h3> There was a significant (P&lt;0.01) increase in standardized scores for the CogState Learning task at visit 2 (105.8±11.2 SD) and visit 3 (111.1±11.4), compared to visit 1 (97.9±11.6). There was a small, but significant (P=0.03) decrease in score for Processing Speed task at visit 2 (99.3±8.2), but not visit 3 (101.6±5.8), relative to first visit (104.8±8.6). <h3>Conclusions</h3> There was significant improvement over one hockey season on the CogState Learning task (one card learning accuracy) in Bantam-aged hockey players with no concomitant significant decrement in other cognitive measures. Though a small study, these results indicate there was no discernible negative effect on cognitive function over the course of one body-checking hockey season.

  PublisherDOI

• Correlation of Adenoviral Titers with Severity of Adenoviral Conjunctivitis and Time to Viral Clearance for 21 Days

  Optometry and Vision Science · 2023-02-07 · 14 citations

  articleOpen access

  SIGNIFICANCE: This investigation reports the correlation of conjunctival viral titers in adenoviral conjunctivitis with patient-reported symptoms and clinician-graded signs for 21 days of follow-up. PURPOSE: Adenoviral conjunctivitis is a highly contagious viral eye infection with significant morbidity and economic impact. This study investigates whether severity of signs and symptoms and time to viral clearance are correlated with conjunctival viral titers at baseline and during 21 days of follow-up. METHODS: The Reducing Adenoviral Patient Infected Days study was a pilot study of the efficacy of a single in-office administration of ophthalmic 5% povidone-iodine. This article outlines longitudinal analyses after the primary outcome report. Of 212 participants screened, 28 participants with quantitative polymerase chain reaction-confirmed adenoviral conjunctivitis were randomized and had follow-up visits on days 1, 2, 4, 7, 14, and 21. At each visit, clinician-graded signs, participant-reported symptoms, and a conjunctival swab for quantitative polymerase chain reaction analysis were obtained. The correlation of viral titers with symptoms and signs was calculated: (1) cross-sectionally at each visit and (2) longitudinally for 21 days using a repeated-measures mixed-effects model. RESULTS: Twenty-five of 28 participants had sufficient data for this report. Higher viral titers for 21 days were correlated with greater severity of symptoms (tearing, matting, and redness, r ≥ 0.70; P < .02) and greater severity of clinical signs (bulbar redness and serous discharge, r ≥ 0.60; P < .01). Eyes with highest baseline viral titers required longer time to viral clearance ( r = 0.59, P = .008). Signs and symptoms persisted in approximately half of the eyes even after viral clearance. CONCLUSIONS: Higher conjunctival viral titers across 21 days were strongly correlated with more severe signs and symptoms and longer time to viral clearance. Our results also indicate that symptoms and signs can persist after viral clearance.

  PublisherOA PDFDOI

• Erratum to Efficacy of a Single Administration of 5% Povidone-Iodine in the Treatment of Adenoviral Conjunctivitis. Am J Ophthalmol 2021;231:28-38

  American Journal of Ophthalmology · 2022-01-19

  erratum
  PublisherDOI

• Foveal Phase Retardation Correlates With Optically Measured Henle Fiber Layer Thickness

  Frontiers in Medicine · 2022 · 1 citations

  • Optics
  • Ophthalmology
  • Materials science

  = 36). Phase retardation maps from SLP imaging were used to generate a macular cross pattern (fixed compensation) or an annulus pattern (variable compensation) centered on the macula. Intensity profiles in the phase retardation maps were produced using annular regions of interest at eccentricities from 0.25° to 3°. Pixel intensity was averaged at each eccentricity, acting as a surrogate for macular phase retardation. Directional OCT images were acquired in the horizontal and vertical meridians in all subjects, allowing visualization of the HFL thickness. HFL thickness was manually segmented in each meridian and averaged. In both cohorts, phase retardation and HFL thickness were highly correlated in the central 3° assessed, providing further evidence that the source of the phase retardation signal in the central macula is dominated by the HFL and that the center of the macula on cross sectional imaging corresponds closely with the center of the macular cross on SLP imaging.

  PublisherDOI

• Success of Masking 5% Povidone‐Iodine Treatment: The Reducing Adenoviral Patient Infected Days Study

  Optometry and Vision Science · 2021-05-01 · 3 citations

  articleOpen access

  SIGNIFICANCE: The effectiveness of masking is rarely evaluated or reported in single- or double-masked clinical trials. Knowledge of treatment assignment by participants and clinicians can bias the assessment of treatment efficacy. PURPOSE: This study aimed to evaluate the effectiveness of masking in a double-masked trial of 5% povidone-iodine for the treatment of adenoviral conjunctivitis. METHODS: The Reducing Adenoviral Patient Infected Days study is a double-masked, randomized trial comparing a one-time, in-office administration of 5% povidone-iodine with artificial tears for the treatment of adenoviral conjunctivitis. Masking was assessed by asking participants and masked clinicians at designated time points if they believed the treatment administered was povidone-iodine or artificial tears, or if they were unsure. Adequacy of masking was quantified using a modified Bang Blinding Index. RESULTS: Immediately after treatment, 34% of participants who received povidone-iodine and 69% of those who received artificial tears guessed incorrectly or were unsure of their treatment (modified Bang Indices of 0.31 and -0.38, respectively). On day 4, 38% of the povidone-iodine participants and 52% of the artificial tear participants guessed incorrectly or were unsure of their treatment (modified Bang Indices of 0.24 and -0.05, respectively), indicating adequate and ideal masking. On days 1, 4, 7, 14, and 21, masked clinicians guessed incorrectly or were unsure of treatment in 53%, 50%, 40%, 39%, and 42% among povidone-iodine participants compared with 44%, 35%, 38%, 35%, and 39% among artificial tears participants, respectively. The modified Bang Indices for clinician masking in the povidone-iodine group ranged from -0.05 to 0.25 and from 0.13 to 0.29 in the artificial tears group. CONCLUSIONS: Masking of participants and clinicians was adequate. Successful masking increases confidence that subjective measurements are not biased. We recommend quantitative assessment and reporting the effectiveness of masking in ophthalmic clinical trials.

  PublisherOA PDFDOI

• Predictive Accuracy and Densitometric Analysis of Point-of-Care Immunoassay for Adenoviral Conjunctivitis

  Translational Vision Science & Technology · 2021-08-25 · 10 citations

  articleOpen accessSenior authorCorresponding

  Purpose: Accurate diagnosis of adenoviral conjunctivitis (Ad-Cs) is important for timely and appropriate patient management to reduce disease transmission. This study assessed the diagnostic accuracy of a commercially available point-of-care adenovirus immunoassay and determined whether its predictive accuracy is influenced by signal intensities of test result bands. Methods: Point-of-care immunoassay (AdenoPlus) testing and quantitative polymerase chain reaction (qPCR) testing was performed on conjunctival swab samples obtained from eyes of 186 eligible adult participants with presumed infectious conjunctivitis and symptoms of ≤4 days. Masked observers assessed signal intensities of the immunoassay test and control bands using densitometry. Results: Ad-Cs was confirmed by qPCR in 28 of the 56 eyes that tested positive on the AdenoPlus, a 50% positive predictive value (95% confidence interval [CI] = 36.9, 63.1). No adenovirus was detected by qPCR in 128 of 130 eyes that tested negative on AdenoPlus, a 98.5% negative predictive value (CI = 96.3, 100). Sensitivity and specificity were 93% (CI = 84.4, 100) and 82% (CI = 76.0, 88.1), respectively. Viral titers significantly correlated with ratio of test band signal intensities (R2 = 0.32, P = 0.002). Higher positive predictive value was associated with higher densitometry ratios (receiver operating characteristic [ROC] area = 0.71; 95% CI = 0.59, 0.83). Conclusions: Densitometric analyses suggest that the diagnostic accuracy of AdenoPlus is influenced by the signal intensity of the test result bands. Visual comparison of the test band intensities by clinicians could reduce the false positive rate of point-of-care immunoassays and aid in the diagnosis of viral infections. Translational Relevance: Ratiometric densitometry of point-of-care immunoassays could aid clinicians' decision making in diagnosing infectious diseases, including Ad-Cs.

  PublisherDOI

• Reducing Adenoviral Patient Infected Days (RAPID) Study: Correlation of adenoviral load with severity of adenoviral conjunctivitis and viral clearance over 21 days

  2021-06-21

  article

Frequent coauthors

• William H. Baldridge

  Dalhousie University

  19 shared

• Ellen Shorter

  17 shared

• Jennifer Harthan

  Illinois College of Optometry

  14 shared

• Tammy Than

  Carl Vinson VA Medical Center

  14 shared

• Spencer Johnson

  Rocky Mountain University of Health Professions

  14 shared

• Christina Morettin

  14 shared

• Mary K. Migneco

  14 shared

• Phillip T. Yuhas

  The Ohio State University

  13 shared

Labs

• ResearchPI

Awards & honors

• ARVO Annual Meeting E-abstract 4360 (2017)
• ARVO Annual Meeting E-abstract 160093 (2016)
• ARVO Annual Meeting E-abstract 620 (2016)
• ARVO Annual Meeting E-abstract 155226 (2016)
• ARVO Annual Meeting E-abstract 150035 (2015)