Eye Chart HD vs WikEM
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Eye Chart HD
This app provides a clinically evaluated visual acuity screening tool for various settings. It offers randomized Snellen, Tumbling E, and other charts to help assess vision, especially when traditional charts are unavailable or memorized. Additional features are available through a monthly subscription.
- Randomized Snellen charts
- Tumbling E charts
- Pocket vision screener
- Line randomization
- Chart selector
- Near vision chart (subscription)
- Amsler Grid (subscription)
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Easy to use, clinically evaluated visual acuity screening app. Over 1M people have downloaded our mobile electronic eye charts for iOS. Read below for more information on the clinical evaluations. Useful for: - Triaging - House visits - Hospital rounds - Emergency rooms - Schools - Patients who have memorized the office chart Eye Chart HD is a pocket vision screener: randomized Snellen, Tumbling E, and other charts to offer a rough but useful screen of visual acuity. Simply press a button to randomize the entire eye chart, or touch an individual line of the chart to randomize that line. Swipe right for the chart selector. Eye care professionals around the world use Snellen Eye Charts to measure visual acuity. However, patients often memorize the classic Snellen chart, leading to less accurate vision measurements. Enter Eye Chart HD! Though this unique, pocket-sized randomizable eye chart should not be used as a primary visual acuity measuring tool, it can provide a handy rough vision screen when a chart is not available, or it can be used to complement static, wall-based Snellen charts. Subscription: In addition to our free features, Eye Chart HD offers a subscription to exclusive paid features, including the Randomizable Near Vision Chart, Line Isolation, Amsler Grid, and Single Optotype Charts! The subscription costs $2.99 per month of access and has to be purchased specially within the app. Once purchased, it is available through an auto-renewing subscription which will renew each month for your convenience until you choose to turn it off. Please let us know if you have any questions about your subscription at eyechartapp@gmail.com. Below is further information on clinical evaluations that have been done. Please do check out the papers cited below if you have concerns. We didn't do these tests and can't speak to them, but we are providing them here for transparency and your reference: Snellen & Tumbling E charts on Eye Chart HD on iPhone: “Comparison of Visual Acuity Measurement Using Three Methods: Standard ETDRS Chart, Near Chart and a Smartphone-Based Eye Chart Application” Clinical Ophthalmology. Conclusion: “VA measurements with the Near Chart and smartphone-based Eye Chart application corresponded well to the standard ETDRS chart, suggesting potential utility of alternative portable VA tests for in-office or remote vision monitoring, particularly during periods of physical distancing such as the Coronavirus disease 2019 (COVID-19) era” Sloan Chart on Eye Chart HD on iPhone: “Does the EyeChart App for iPhones Give Comparable Measurements to Traditional Visual Acuity Charts?” The British and Irish Orthoptic Journal. Conclusion: “This study found that the VA scores achieved on the EyeChart app are comparable to those achieved using the gold-standard ETDRS chart in a healthy young adult population. This is a promising finding; however, it is necessary for further large-scale studies to investigate the EyeChart app when used on a variety of patient population groups.” Snellen Chart on Eye Chart HD on iPad Mini: “Comparative Study of the Snellen iPad App versus Traditional Light Box Snellen Chart in Distance Visual Acuity” International Journal of Ophthalmology and Clinical Research. Conclusion: “It showed that the results from Eye Chart HD app used in an iPad Mini 2 agreed with the results of the traditional light-box Snellen Chart when used at the Outpatient Department.“ Rapid Vision Screening Chart on Eye Chart HD on iPhone/iPod: “Assessment of a rapid method to determine approximate visual acuity in large surveys and other such settings.” American Journal of Ophthalmology. Conclusion: “An iPod application requiring about a 1-minute testing time provides an objective, portable, rapid, and low-cost method to determine approximate VA, allowing VA testing to be performed efficiently in large surveys and other settings where approximate VA should be measured.”
WikEM
This app provides a continuously updated wiki and database of emergency medicine knowledge for physicians. Access key information offline for rapid reference during daily practice. An in-app subscription unlocks advanced AI-powered questions, favorites, and history features.
- Emergency medicine knowledge database
- Continuously updated content
- Offline access
- AI-powered questions (subscription)
- Favorites and history (subscription)
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WikEM is an online wiki and database of emergency medicine knowledge to assist physicians with their daily practice. The content is continuously updated from WikEM.org allowing for rapid reference of key information. The content is available offline with this mobile application. WikEM is intended for clinicians only and not directly for patients. In app subscription purchases: *The in-app purchase unlocks unlimited natural language questions using our AI and also favorites and history features • Payment will be charged to iTunes Account at confirmation of purchase • Subscription automatically renews unless auto-renew is turned off at least 24-hours before the end of the current period • Account will be charged for renewal within 24-hours prior to the end of the current period, and identify the cost of the renewal • Subscriptions may be managed by the user and auto-renewal may be turned off by going to the user's Account Settings after purchase • Any unused portion of a free trial period, if offered, will be forfeited when the user purchases a subscription to that publication, where applicable WikEM terms of use: wikem.org/wiki/WikEM:Terms_of_Use
Screenshots
Verdict
The clearest difference is ads: WikEM at none against Eye Chart HD's shown. WikEM also leads on update cadence (every 5 days vs every 6 months) and rating (4.8 vs 4.4). Eye Chart HD's advantage is iOS requirement (12.0 vs 15.1). On price, in-app purchases, monetization model and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Eye Chart HD sells 2 in-app purchases, starting at $2.99 per month and WikEM sells 10 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.
WikEM holds the better App Store score, 4.8 against 4.4. That said, the two scores are not equally well evidenced: WikEM has 4.8K ratings behind it against 7, so its average is the more settled of the two. Written reviews point the same way: 33% of Eye Chart HD's written reviews are positive against 54% of WikEM's.
Eye Chart HD ships an update every 6 months, WikEM every 5 days. The most recent releases landed on October 29, 2026 and November 1, 2026 respectively.
| Parameter | Eye Chart HD | WikEM |
|---|---|---|
| Price | Free | Free |
| Rating | 4.4 (7 ratings) | 4.8 (4.8K ratings) — better |
| Positive reviews | 33.3% of reviews | 54.1% of reviews — better |
| Number of ratings | 7 | 4.8K — better |
| Update frequency | Every 6 months | Every 5 days — better |
| Ads | Yes | No — better |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 12.0 — better | 15.1 |
| Further details — not scored | ||
| Size | 31 MB | 167 MB |
| Age rating | 4+ | 17+ |
| Developer | Dok LLC | OpenEM Foundation |
Customer experience
Eye Chart HD
WikEM
Bugs and requests
Eye Chart HD
Not enough reviews yet to summarise bugs or requests.
WikEM
Reported bugs
4 issues- Login screen freezes
- Incompatible with older devices
- Broken hyperlinks and charts
- Search function not working as expected
Requested features
4 requests- Dark mode support
- Ability to save favorites and customize the app
- Improved search functionality
- Regular content updates
In-app purchases
Eye Chart HD
- Professional Subscription$2.991 Month
- Eye Chart HD Full Version$0.99
WikEM
- WikEM AI Search$1.991 Month
- Premium Features$4.991 Year
- Personal Notes$0.99
- Favorites and Lists$5.99
- History and Favorites$9.99
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- WikEM Russian Content$29.99
- WikEM Italian Content$29.99
- WikEM Polish Content$29.99
- WikEM Hindi Content$29.99
- WikEM Turkish Content$29.99







