REPLY THE AUTHORS APPRECIATE THE COMMENTS OF SANHARAWI
and associates with respect to our recent paper.1 We agree that using the first date of cataract diagnosis for our case definition would be preferable when examining the etiologic relationship between atypical antipsychotics and cataracts. The primary concern in our regional practice patterns centered on the lack of standardized diagnostic criteria for ophthalmologists when evaluating lenticular opacity. In many instances, it may have been solely for billing reasons and bore no relationship with visual disability. As such, we chose to use first cataract procedure as our case definition to reflect the formation of a visually significant cataract for that patient in question, which accounts for factors mentioned, such as vocational needs. Sanharawi and associates also suggest conducting separate, fully adjusted models on risk factors before deciding on whether a variable may be considered a control group in the study. We argue against this approach, which would treat a risk factor as the main study exposure. In epidemiologic studies, the exposure usually is defined based on an a priori hypothesis with careful consideration of the time to disease onset. Risk factors are defined more crudely at baseline, and thus a lack of association between a risk factor and disease in a particular study does not necessarily exclude the presence of an association. We chose oral corticosteroid users as a positive control because it is well established (both from our study and others) that they increase the risk of cataracts. Selective serotonin reuptake inhibitors did not increase the risk of cataracts in this study. We found a slight increase in the risk associated with selective serotonin reuptake inhibitors (adjusted rate ratio: 1.15; 95% confidence interval: 1.08-1.23) in a different cohort of patients with a history of cardiovascular disease.2 We agree that the risk of selective serotonin reuptake inhibitors and cataracts must be investigated in future studies. With respect to not controlling for smoking, we believe this was addressed adequately in the Discussion. With respect to controlling for diabetes, antidiabetic medications were used to identify those with diabetes, the diagnosis of which is itself a cataract risk factor.3 Antidiabetic medications have been used previously as a variable related to cataract.3 Glucose control was not our variable of interest. We agree that those patients being treated for end-stage dementia with antipsychotics may not have equal access to cataract surgery given issues with consent, cooperation, and occasionally anesthesia. As such, we appreciate the suggestion to correlate antipsychotic use with medications for dementia. We note that in our region and others, mildto-moderate dementia is not a deterrent to cataract surgery referral,4 possibly with greater access given safety recommendations1 and possible cognitive improvement.5 Our conclusions should be interpreted in the context of retrospective study limitations, particularly those discussed.1
VOL. 157, NO. 3
As mentioned, the major contribution of our findings was to generate a hypothesis that requires further testing under more definitive circumstances, such as a future prospective study with comprehensive variable control. We believe this study is an important contribution to the scientific method, offering hypotheses both to clinicians and basic scientists alike. KAIVON L. PAKZAD-VAEZI MAHYAR ETMINAN FREDERICK S. MIKELBERG
Vancouver, Canada CONFLICT OF INTEREST DISCLOSURES: SEE THE ORIGINAL article for any disclosures of the authors.
REFERENCES
1. Pakzad-Vaezi KL, Etminan M, Mikelberg FS. The association between cataract surgery and atypical antipsychotic use: a nested case-control study. Am J Ophthalmol 2013;156(6): 1141–1146. 2. Etminan M, Mikelberg FS, Brophy JM. Selective serotonin reuptake inhibitors and the risk of cataracts: a nested case control study. Ophthalmology 2010;117(6):1251–1255. 3. Rowe NG, Mitchell PG, Cumming RG, Wang JJ. Diabetes, fasting blood glucose and age-related cataract: the Blue Mountains Eye Study. Ophthalmic Epidemiol 2000;7(2):103–114. 4. Ryyna¨nen OP, Myllykangas M, Kinnunen J, Takala J. Doctors’ willingness to refer elderly patients for elective surgery. Fam Pract 1997;14(3):216–219. 5. Ishii K, Kabata T, Oshika T. The impact of cataract surgery on cognitive impairment and depressive mental status in elderly patients. Am J Ophthalmol 2008;146(3):404–409.
Teaching Ophthalmoscopy to Medical Students (TOTeMS) II: A One-Year Retention Study TO THE EDITOR: WE RECENTLY DEMONSTRATED THAT MEDICAL STUDENTS
after their first-year ophthalmology training not only examined the ocular fundus more accurately with photographs than with direct ophthalmoscopy, but also preferred using photographs.1 One year later, we completed a follow-up study to test our hypothesis that these differences would persist over time. Second-year medical students were reevaluated on their ability to examine the ocular fundus after randomization to either fundus photographs or direct ophthalmoscopy on eye simulators.2 All students recorded answers to a questionnaire1 assessing their ability to visualize features of the ocular fundus, positive and negative affect,3 preferences, and their clinical experiences during the previous year with ocular fundus examination. The study was institutional review
CORRESPONDENCE
747
board–approved, in accordance with Health Insurance Portability and Accountability Act regulations, and informed consent was obtained from subjects. Of 119 students, 107 (90%) who participated in the original study completed this 1-year follow-up study. Of 48 questions, students answered 34.5 (72%) correctly using photographs vs 31.4 (65%) using direct ophthalmoscopy (P ¼ .004). Two series of questions used the same images for both the simulator and photographs, and students performed better using photographs (mean: 16.6 vs 14.3 of 24 correct; P ¼ .0008). Both photography and ophthalmoscopy groups correctly answered 5 fewer questions on average than 1 year prior (P < .001). Students rated photographs as ‘‘easier than ophthalmoscopy’’ (mean: 7.9/10 vs 5.9/10, respectively; P < .001). Students’ positive affect scores were higher in the photograph group (26.5) than in the ophthalmoscopy group (23.2; P ¼ .03). Students tested on simulators reported lower positive affect than 1 year ago (6.4 points, P < .001). Students’ self-reported median frequency of fundus examination over the preceding year was
and associates with respect to our recent paper.1 We agree that using the first date of cataract diagnosis for our case definition would be preferable when examining the etiologic relationship between atypical antipsychotics and cataracts. The primary concern in our regional practice patterns centered on the lack of standardized diagnostic criteria for ophthalmologists when evaluating lenticular opacity. In many instances, it may have been solely for billing reasons and bore no relationship with visual disability. As such, we chose to use first cataract procedure as our case definition to reflect the formation of a visually significant cataract for that patient in question, which accounts for factors mentioned, such as vocational needs. Sanharawi and associates also suggest conducting separate, fully adjusted models on risk factors before deciding on whether a variable may be considered a control group in the study. We argue against this approach, which would treat a risk factor as the main study exposure. In epidemiologic studies, the exposure usually is defined based on an a priori hypothesis with careful consideration of the time to disease onset. Risk factors are defined more crudely at baseline, and thus a lack of association between a risk factor and disease in a particular study does not necessarily exclude the presence of an association. We chose oral corticosteroid users as a positive control because it is well established (both from our study and others) that they increase the risk of cataracts. Selective serotonin reuptake inhibitors did not increase the risk of cataracts in this study. We found a slight increase in the risk associated with selective serotonin reuptake inhibitors (adjusted rate ratio: 1.15; 95% confidence interval: 1.08-1.23) in a different cohort of patients with a history of cardiovascular disease.2 We agree that the risk of selective serotonin reuptake inhibitors and cataracts must be investigated in future studies. With respect to not controlling for smoking, we believe this was addressed adequately in the Discussion. With respect to controlling for diabetes, antidiabetic medications were used to identify those with diabetes, the diagnosis of which is itself a cataract risk factor.3 Antidiabetic medications have been used previously as a variable related to cataract.3 Glucose control was not our variable of interest. We agree that those patients being treated for end-stage dementia with antipsychotics may not have equal access to cataract surgery given issues with consent, cooperation, and occasionally anesthesia. As such, we appreciate the suggestion to correlate antipsychotic use with medications for dementia. We note that in our region and others, mildto-moderate dementia is not a deterrent to cataract surgery referral,4 possibly with greater access given safety recommendations1 and possible cognitive improvement.5 Our conclusions should be interpreted in the context of retrospective study limitations, particularly those discussed.1
VOL. 157, NO. 3
As mentioned, the major contribution of our findings was to generate a hypothesis that requires further testing under more definitive circumstances, such as a future prospective study with comprehensive variable control. We believe this study is an important contribution to the scientific method, offering hypotheses both to clinicians and basic scientists alike. KAIVON L. PAKZAD-VAEZI MAHYAR ETMINAN FREDERICK S. MIKELBERG
Vancouver, Canada CONFLICT OF INTEREST DISCLOSURES: SEE THE ORIGINAL article for any disclosures of the authors.
REFERENCES
1. Pakzad-Vaezi KL, Etminan M, Mikelberg FS. The association between cataract surgery and atypical antipsychotic use: a nested case-control study. Am J Ophthalmol 2013;156(6): 1141–1146. 2. Etminan M, Mikelberg FS, Brophy JM. Selective serotonin reuptake inhibitors and the risk of cataracts: a nested case control study. Ophthalmology 2010;117(6):1251–1255. 3. Rowe NG, Mitchell PG, Cumming RG, Wang JJ. Diabetes, fasting blood glucose and age-related cataract: the Blue Mountains Eye Study. Ophthalmic Epidemiol 2000;7(2):103–114. 4. Ryyna¨nen OP, Myllykangas M, Kinnunen J, Takala J. Doctors’ willingness to refer elderly patients for elective surgery. Fam Pract 1997;14(3):216–219. 5. Ishii K, Kabata T, Oshika T. The impact of cataract surgery on cognitive impairment and depressive mental status in elderly patients. Am J Ophthalmol 2008;146(3):404–409.
Teaching Ophthalmoscopy to Medical Students (TOTeMS) II: A One-Year Retention Study TO THE EDITOR: WE RECENTLY DEMONSTRATED THAT MEDICAL STUDENTS
after their first-year ophthalmology training not only examined the ocular fundus more accurately with photographs than with direct ophthalmoscopy, but also preferred using photographs.1 One year later, we completed a follow-up study to test our hypothesis that these differences would persist over time. Second-year medical students were reevaluated on their ability to examine the ocular fundus after randomization to either fundus photographs or direct ophthalmoscopy on eye simulators.2 All students recorded answers to a questionnaire1 assessing their ability to visualize features of the ocular fundus, positive and negative affect,3 preferences, and their clinical experiences during the previous year with ocular fundus examination. The study was institutional review
CORRESPONDENCE
747
board–approved, in accordance with Health Insurance Portability and Accountability Act regulations, and informed consent was obtained from subjects. Of 119 students, 107 (90%) who participated in the original study completed this 1-year follow-up study. Of 48 questions, students answered 34.5 (72%) correctly using photographs vs 31.4 (65%) using direct ophthalmoscopy (P ¼ .004). Two series of questions used the same images for both the simulator and photographs, and students performed better using photographs (mean: 16.6 vs 14.3 of 24 correct; P ¼ .0008). Both photography and ophthalmoscopy groups correctly answered 5 fewer questions on average than 1 year prior (P < .001). Students rated photographs as ‘‘easier than ophthalmoscopy’’ (mean: 7.9/10 vs 5.9/10, respectively; P < .001). Students’ positive affect scores were higher in the photograph group (26.5) than in the ophthalmoscopy group (23.2; P ¼ .03). Students tested on simulators reported lower positive affect than 1 year ago (6.4 points, P < .001). Students’ self-reported median frequency of fundus examination over the preceding year was
