Retinal pathology is common in younger people with high myopia

Paper title: Prevalence and related factors of myopic retinopathy - a hospital-based cross-section study in Vietnam

Authors: Hien Thu Thi Nguyen (1), Tung Thanh Hoang (2,3), Chau Minh Pham (1), Thao Manh Nguyen (1), Trung M Dang (4) & Timothy R Fricke (5,6,7)

1. Vietnam National Eye Hospital, Hanoi, Vietnam.
2. Hanoi Medical University, Hanoi, Vietnam.
3. Save Sight Institute, University of Sydney, New South Wales, Australia.
4. Eye Clinic Albury-Wodonga, Albury, New South Wales, Australia.
5. Brien Holden Vision Institute, Sydney, New South Wales, Australia.
6. Department of Optometry and Vision Sciences, University of Melbourne, Victoria, Australia.
7. School of Optometry and Vision Science, University of New South Wales, New South Wales, Australia.

Date: Feb 2022

Reference: Nguyen HTT, Hoang TT, Pham CM, Nguyen TM, Dang TM, Fricke TR. Prevalence and related factors of myopic retinopathy - a hospital-based cross-section study in Vietnam. Clin Exp Optom. 2022 Feb 20:1-4.

[Link to abstract]

The highest prevalence of myopia is currently in Asia.¹  An emphasis on education and economic development in countries in South East Asia has seen increasing numbers of people younger than 40 years with myopia.

This prospective cross-sectional study was based in the refraction service at Vietnam National Eye Hospital and examined the eyes of 88 participants who were over 12yrs of age with high myopia of -6.00D with the aim of investigating the prevalence and signs of myopic retinopathy.

Myopic severity was confirmed by cycloplegic retinoscopy, ocular parameters were measured using IOL Master and the anterior and posterior segments were examined by slit-lamp examination, fundoscopy and Ocular B-scan ultrasound. Cirrus Optical Coherence Tomography was used to image the optic nerve head and macula and the META-PM Study grading system was used to assess the presence of myopic macular retinopathy.

• The mean age of the participants was 20.35±7.19yrs with a total age range from 12 to 47yrs. Children aged between 12 and 18yrs accounted for over half of the total participants.
• The mean spherical equivalent refractive error was -8.75±2.61D, with the highest refractive error -19.75D.  An average axial length of 27.33±1.48mm was found.
• The average age of myopia diagnosis was 9.13±3.57yrs and an average period of time since the diagnosis of 11.21±6.01yrs.
• Neither retinal detachment or retinal holes were found in any participants, although 43.5% had detectable myopia-related peripheral lesions.
• Central retinal changes were found in 66% of the participants and peripapillary atrophy in 70%.

Prevalence odds ratios were calculated for each potential factor of myopic complication. Having myopia of -8.00D or more, an axial length of ≥26.5mm, being 19yrs old or over and having been myopic for 6yrs or more were all associated with additional risks of myopic retinopathy.

The age of myopia diagnosis and family ocular history was found to not be significantly associated with an increased risk of retinal changes.

This study has reinforced findings from previous studies^2,3,4 by showing that myopia-related retinal changes in younger Vietnamese people are common if they are 19yrs or older, highly myopic with long axial lengths and who have been myopic for several years.

Retinal complications associated with myopia can become apparent with age and associated visual impairment can occur after 55yrs old.^5,6

The participants in this study were aged between 12 and 47yrs old and 70% had peripapillary changes already, demonstrating that age itself may not be the largest influence on myopia-related risks.

• The prevalence of high myopes with retinal problems will increase as these younger patients age
• Severity of myopia and longer axial lengths should guide examination of the peripheral retina, rather than the patient's age.

The number of patients with high myopia and subsequent increased risk of retinal complications can be reduced by:

• Recognising that young people are still at risk of developing retinal issues due to their myopia and peripheral retinal screening should be considered
• Limiting myopic prevalence and delaying myopia onset by encouraging children to spend time outside^7,8
• Using myopia management options to slow progression.

The participants in this study attended the Vietnam National Eye Hospital from across the country, suggesting they were representative of the Vietnamese population for the prevalence of pathological myopia complications.

• Further research using prospective cohort design over a longer time period could confirm the findings on a larger scale and establish the prevalence of complications for different age groups
• This could allow for more accurate predictions of the risks of high myopia
• Repeating the studies in different countries could allow for cultural differences such as outdoor lifestyle and educational intensity to be investigated.^9,10

Title: Prevalence and related factors of myopic retinopathy - a hospital-based cross-section study in Vietnam

Authors: Hien Thu Thi Nguyen, Tung Thanh Hoang, Chau Minh Pham, Thao Manh Nguyen, Trung M Dang & Timothy R Fricke

Purpose: To evaluate the prevalence and related factors of myopic retinopathy in Vietnam

Methods: A cross-sectional study was conducted on 168 eyes of 88 patients with high myopia presenting to the Refraction Department of Vietnam National Eye Hospital. Inclusion criteria were high myopia (≤-6.00D with cycloplegic retinoscopy). Consecutive presenting patients recruited between January 2020 and August 2020 consented to participate.

Results: Participant age range was 12-47 years. Peripapillary atrophy was present in 70.2% of participants, most commonly atrophy of one-quarter of the disc (38.7%). Central retinal changes were present in 66.1% of participants, subclassified as tessellated fundus in 60.7%, diffuse chorioretinal atrophy in 4.2% and patchy chorioretinal atrophy in 1.2%. Peripheral retinal lesions were present in 43.5% of participants, consisting of white-without-pressure in 32.1%, lattice degeneration in 16.1%, snail track degeneration in 4.2% and microcystoid degeneration in 1.2%. Myopia ≤-8.00D and axial length ≥26.5 mm were associated with additional risk of posterior ocular complications. Furthermore, age ≥19 years increased risk of central myopic retinopathy and ≥10 years since initial myopia diagnosis increased the risk of peripapillary atrophy and central retinal changes. Other factors such as the age of onset of myopia and family myopia history did not appear to alter the risk of peripheral retina damage.

Conclusions: Retinal disorders were common in Vietnamese people with high myopia. Within the current cohort with high myopia, myopia ≤-8.00D and axial length ≥26.5 mm were associated with a significant further elevation of risk.

[Link to abstract]