The 20/20/20 rule: Practicing pattern and associations with asthenopic symptoms

When noise becomes signal: a study of blink rate using an eye tracker

PURPOSE

Although blink rate is considered important for digital eye strain and dry eye conditions, its assessment has been mostly manual. This study aimed at quantifying blink rate automatically using the Eyelink 1000 Plus eye tracker and comparing it with manual counting. Additionally, blink rate was correlated with reading eye movements and reading speed.

METHODS

Thirty participants (mean age 26.8±3.5 years; 19 females) were enrolled. An on-screen reading task for 3 minutes duration, was repeated 3 times with a 2-minute break between the repetitions. During this task, eye movements and blinks were measured through the Eyelink 1000 Plus eye tracker. The blink was also counted manually by the examiner in real time from a video feed.

RESULTS

The blink rate obtained by the eye tracker (median [Q1, Q3]:11.7 [6.8,15.5] blinks/min) and manual counting (11.6 [7.1, 15.4] blinks/min) were comparable (p>0.5). No significant correlations were observed between the blink rate and any of the reading eye movement parameters except saccadic amplitude (Spearman's rho, rs =0.506). No statistically significant correlation was found between the blink rate and reading speed.

CONCLUSION

The Eyelink 1000 Plus eye tracker gives a comparable blink rate compared to that obtained through manual counting. A positive correlation between the blink rate and saccade amplitude could indicate a coupled interaction between the two mechanisms to minimize visual loss during reading. The option of using this tracker to investigate blinks in dry eye and binocular vision disorders can be further explored.

Digital Eye Strain: Updated Perspectives

Purpose

Digital eye strain (DES) is a growing worldwide concern because digital devices are prevalent in both our work and home lives. The purpose of this review was to summarize clinically relevant and evolving key topics related to DES.

Methods

A PubMed.gov search was conducted on or before June 8, 2024. No date restrictions were used during the primary search. The search was aimed at detecting all articles related to DES; thus, the search terms only included "digital eye strain" or "computer vision syndrome".

Results

The two most used, validated DES questionnaires are the Computer Vision Syndrome Questionnaire (CVS-Q) and Computer Vision Symptom Scale (CVSS17). The world-wide prevalence of DES ranges from 8.2% to 100% depending upon the subjects evaluated and the method used to evaluate them. The most common DES symptoms include headache, eye strain, eye redness, eye itching, tearing, photophobia, burning sensation, blurred vision, eye pain, neck and shoulder pain, and eye dryness. Ocular surface symptoms in DES are integrally tied to decreased blink frequency, which causes ocular surface desiccation, increased osmolarity, and dry eye-like symptoms. The most studied DES-specific treatments are improving subjects' environment, artificial tears, blinking exercises, and near work breaks.

Conclusion

DES is a highly prevalent condition that should be regularly screened for in clinic with a validated diagnosis instrument. While there are several treatment options, the community's treatment approach is evolving and primarily focused on treating the visual and dry eye-like symptoms associated with the condition.

Understanding visual snow syndrome: A retrospective study from a tertiary eye care center

PURPOSE

Visual snow syndrome is a debilitating neurological condition. A comprehensive eye examination may not detect any abnormalities in this condition. Presently the condition is recognized only through the history elicited. Hence, it becomes important to understand the presenting complaints and profile of these patients. A retrospective study at a tertiary eye care center was undertaken to achieve this goal.

METHODS

Electronic medical records of patients presenting to a Binocular Vision and Orthoptics clinic were reviewed. Records of the patients containing keywords such as "light sensitivity, shadowing, visual snow, multiple images, and night vision" were retrieved and inspected. Those matching the diagnostic criteria of visual snow syndrome were included in the study.

RESULTS

A total of 33 patients (average age ± standard deviation: 29.7 ± 9.8 years) were identified. Majority of the patients were males (69%). All the patients had logMAR visual acuity 0 or better in each eye. The most prominent (84.4%) presenting symptom was palinopsia (or afterimage or trailing). About 34.4% complained of floaters (including snow-like appearance). More than half (54.6%) of the patients also had binocular dysfunction.

CONCLUSION

Visual snow syndrome is a relatively new condition on the rise, with unclear pathology. The symptoms of this condition can easily be confused with regular floaters or black spots seen in vitreous and retinal pathologies. In the absence of such pathology, an elaborate history should be elicited, and the distress of the patient should be acknowledged. The patient should also be reassured that this is not a blinding condition.