Spectacle dispensing for myopia at primary eye care level

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The prevalence of myopia has been progressively increasing^1,2,3 and is due to changes in lifestyle or reduced outdoor activity. Myopia is easily corrected with a pair of spectacles. However, lack of access to refractive assessment and availability of spectacles remain the key challenge in addressing uncorrected refractive error.⁴ Primary eye care services are best positioned to create and sustain such accessibility. Well-designed primary eye care can provide the required refractive correction for the community.

These services need to be comprehensive and include not only refractive assessment and prescription, but also, spectacle dispensing. It has been noted that making spectacles available on the spot is important to ensure uptake and use.⁵

This article discusses guidelines for how myopia correction can be provided at the community level though outreach camps and primary care centres. To make spectacle dispensing available, we need to have systems in place to provide the right inventory of lenses and the right kind of frames stocked to ensure uptake and patient satisfaction.

Guidelines for prescribing glass

Glasses need to be prescribed based on the individuals’ needs and symptoms. Most practioners prescribe spectacles for a refractive error of −0.75 DS and less only if the patient is symptomatic.⁶ Spectacles should be prescribed based on the patient’s subjective refraction and not merely retinoscopy findings. Those with presbyopia may be given the option to remove their myopia glasses for reading or use bifocals.

Cycloplegic refraction is recommended when prescribing glasses for the first time especially in children less than 15 years of age. The AAO paediatric ophthalmology panel recommends prescribing glasses for myopia of:

• 5.00 DS or more in infants,
• 4.00 DS or more in children between one to two years of age
• 3.00 DS or more in those between two to three years of age and
• 2.50 or more in children over three years of age.⁷

Spectacles need to be prescribed for even lower refractive errors in those with anisometropia.

Guidelines for dispensing spectacles

While dispensing spectacles, it is important to take into account the patients need, vocation and socio- economic background. Opticians need to guide patients to choose appropriate frames. Frames that are too large can slip down the nasal bridge and could disturb the alignment of optic centre of the lenses to the patients’ pupil. In younger children, plastic frames and plastic lenses are recommended to avoid injury to the eye if the spectacles break.⁸

• Plastic lens (CR 39) has the advantage of being safe and more durable. However, the edging and fitting of these lenses need more sophisticated equipment which is neither suitable for portable use nor feasible for a small scale of operations. Also, as these lenses tend to yellow over time, they cannot be stocked for long periods. Plastic lenses are available with additional features such as anti-reflection, UV protection, scratch resistance, high refractive index lenses etc.
• Glass lenses are cheaper, easier to process and are less prone to scratches; although they are heavier and can break more easily. Glass lenses are used for eye camps as they are less expensive and can be edged by hand using a portable edging machine.
• For patients with high myopia, lenses with high refractive index are thinner and give a better cosmetic result. They are available both in plastic and glass and are best if dispensed with anti-reflection coating.
• Polycarbonate lenses are recommended for children for safety but they are more expensive; these are especially recommended for those who are one-eyed and need spectacles for protection.

Spectacle dispensing in outreach camps

Outreach camps are designed to include a refraction assessment as part of the standard clinical examination. On-the-spot dispensing of spectacles at the campsite ensures uptake and use of spectacles. Often 15-25% of the patients at a camp will require spectacles and the lens inventory stock must be planned accordingly and at affordable prices. Refractive camps conducted at workplaces are a good way to address uncorrected refractive error in the working age group. As the number of patients who require spectacles is around 35% in these camps, a larger inventory needs to be planned.

Patients are offered a choice of spectacle frames to choose from. A standard inventory of ready-made lenses has been developed for different sized camps. Ready-made lenses in common power ranges are easily available in the market. Usually this can cater to about 90% of the prescriptions. Lenses for high powers, mixed astigmatism and hyperopic astigmatism are rarely required and hence not stocked – these are made to order against a prescription and couriered to the patient. This arrangement can ensure an increased spectacle uptake of about 80% among those who are given prescriptions.⁹

Table 1 What do you need to dispense spectacles at an outreach camp?

Spectacle dispensing at primary eye care centres

Primary eye care services must include refractive error assessment and spectacle dispensing. A simple way to provide spectacles is to offer a range of spectacle frames and outsource edging and fitting of the lenses. At Aravind Eye Care System in India, a network of primary eye care centres or vision centres are linked to the central spectacle processing unit at the base hospital.

These VCs are manned by two vision technicians. Patients receive a comprehensive eye examination including refractive evaluation and consult with an ophthalmologist using telemedicine. Each VC carries a standard display of about 80 frame models of varying colours, models and sizes, besides a small inventory of reading glasses. An online ordering system conveys the choice of frame, lens type and prescription details to the central spectacle processing unit. This allows the patient to have the choice of ordering plastic lenses. Spectacles are delivered to the patient within one to three days. This ensures over 90% uptake of spectacles and spectacle sales contribute over 60% of these centres’ income.

References

1. Lin LL, Shih YF, Hsiao CK, et al. Prevalence of myopia in Taiwanese schoolchildren: 1983 to 2000. Ann Acad Med Singapore 2004; 33:27–33.
2. Yan Li, Jia Liu, Pengcheng Qi. The increasing prevalence of myopia in junior high school students in the Haidian District of Beijing, China: a 10-year population-based survey. BMC Ophthalmol. 2017; 17: 88.
3. Vitale S, Sperduto RD, Ferris FL. Increased prevalence of myopia in the United States between 1971-1972 and 1999-2004. Arch Ophthalmol 2009; 127:1632–1639.
4. Marmamula S, Keeffe JE, Raman U, Rao GN. Population-based cross-sectional study of barriers to utilisation of refraction services in South India: Rapid Assessment of Refractive Errors (RARE) Study. BMJ Open. 2011;1(1):e000172. Published 2011 Jul 15. doi:10.1136 bmjopen-2011-000172
5. Ramasamy D, Joseph S, Valaguru V, Mitta VP, Ravilla TD, Cotch MF. Cluster randomized trial to compare spectacle delivery systems at outreach eye camps in South India. Ophthalmic Epidemiol. 2013;20(5):308-14.
6. Shneor E, Evans BJ, Fine Y, Shapira Y, Gantz L, Gordon-Shaag A. A survey of the criteria for prescribing in cases of borderline refractive errors. J Optom. 2015;9(1):22–31. doi:10.1016/j.optom.2015.09.002
7. AAO PPP Paediatric Ophthalmology/Strabismus Panel, Hoskins Center for Quality Eye Care. American Academy of Ophthalmology. 2017. Paediatric Eye Evaluations PPP – 2017
8. Sharma P, Gaur N. How do we tackle a child’s spectacle?. Indian J Ophthalmol. 2018;66(5):651–652. doi:10.4103/ijo.IJO_369_18
9. Naidoo K, Ravilla D. Delivering refractive error services: primary eye care centres and outreach. Community Eye Health. 2007;20(63):42–44.