Introduction

Uncorrected refractive errors contribute to nearly half the incidences of visual impairment globally [1]. The problem is more common in remote rural areas of developing countries. In India, 16% of blindness and 46% of visual impairment is caused by uncorrected refractive errors [2, 3]. About 55% of people over the age of 30 years have uncorrected presbyopia [4]. “Low cost spectacles” refers to the provision of good quality spectacles at a cost affordable by a majority of the people in need for correction of refractive errors and presbyopia.

Relevance of low cost spectacles

The burden of uncorrected refractive errors and presbyopia can be explained by considering it under two categories: 1) Creating a system to assess the refractive error with reasonable accuracy to determine the power of the spectacles required, and 2) Provision of appropriate spectacles. For the majority of the needy in rural areas, both issues pose a formidable challenge because they relate to affordability, availability and accessibility in the provision of prescription spectacles. For a sustainable service delivery model of low cost spectacles, the quality, comfort, endurance and accuracy of the prescription are all equally important. Dandona et al. found that nearly one-third of the subjects with significant visual impairment discontinued the use of spectacles either because they felt the prescription was wrong, or because the spectacles were uncomfortable [5]. There are similar reports from Timor- Leste [6].

Strategies to provide low cost spectacles

A) LV Prasad Eye Institute (LVPEI) - Vision Centre model

LVPEI’s Vision Centre model (primary eye care centres) was developed to provide quality primary eye care through three core activities: recognize common eye conditions that cause visual impairment; refract, prescribe and dispense spectacles at an affordable cost; and provide appropriate referral service for conditions that need further evaluation and management. A new cadre of eye care personnel termed ‘Vision Technicians’ was developed primarily because qualified optometrists and ophthalmologists are least likely to work in these rural communities. A Vision Technician is trained for an year on the necessary knowledge, skills and attitude to work in a Vision Centre that functions as a well equipped walk-in screening clinic designed to address the primary eye care needs of a rural population of 50,000 to 100,000, living in its vicinity [7]. Eye examination is free of charge and the spectacles are low cost. The sale of low cost spectacles is the only source of income for a Vision Centre.

Typically, ten Vision Centres are linked to a secondary Service Centre (Fig. 1), which is the nodal point providing administrative and referral support to the Vision Centres. The Service Centre’s centralized optical unit (edging and fitting unit) caters to the patients of the 10 Vision Centres.

Fig. 1: L V Prasad Eye Institute eye care service delivery pyramid.

Lenses are fitted to the frames using the optical unit’s stock lenses or lenses received from the supplier for powers not available in the stock. These spectacles are then sent back to the Vision Centres within 3-4 working days for the patients to collect. The performance of the Vision Centres in shown in Table 1.

Tab. 1: Correction of refractive errors through Vision Centres. 
*Number of Vision Centres increased from 1 in 2003 to 65 in 2010.

B) Community based screening programmes

Community based screening programmes have make-shift camps to assess refractive errors, prescribe and dispense low cost spectacles. Patients needing complex prescriptions are delivered their spectacles on a later day. Aravind Eye Hospital pioneered this model of care in 1976. In 2005, these eye camps screened over half a million people and 80% of the ordered spectacles were delivered “on the spot”. The average price paid by the patient for a pair of spectacles was about Rs 150 (US $ 3.50) [8].

Another initiative is that of Essilor Vision Foundation’s well-equipped vans that carry vision screening equipment, a stock of powered lenses, edging and fitting equipment. Over 75,000 people in underserved areas benefited through this model during 2006 and 2009 (Essilor Annual report 2009).

Also, LVPEI’s Nimmagadda Children's Eye Health initiative screened nearly 137,000 children and provided spectacles to over 11,000 children at no cost.

Challenges in the provision of low cost spectacles

The cost of spectacles is determined by a variety of factors including manufacturing cost, demand and supply, market dynamics, the supply chain involved in servicing remote rural areas, etc.

Fig. 2: Vision Centres in Andhra Pradesh (Centre of Excellenc, Tertiary Care Centres, Secondary Care Centres, Primary Care Centres).

Creating a custom-lenses surfacing lab is feasible only if the patient volumes are high to sustain the costs. Even though custom-made lenses comprise between 50-60% of the prescriptions issued in day, it can be challenging to service widespread geographic areas. Spherical equivalents can be dispensed, without compromising significantly on best corrected visual acuity.

Industrial bulk purchasing and procurement can be a useful modality to keep the costs low. But this needs large investments, ground research to understand the commonly prescribed range of powers of lenses, accurate projection of the volumes, etc. Also, the time lag between the procurement of the stock and getting the return on investment may be a deterrent, as also the frequent changes in the trends of designs and models of the frames.

A strategy to provide “ready-made” and “re-cycled” spectacles was attempted by several organizations - including LVPEI - to provide spectacles at a low cost or even at no cost. But the results have not been very encouraging.

Conclusion

A multi-pronged strategy is required to address the burden of uncorrected refractive errors and presbyopia through the provision of low cost spectacles in India to fulfill the objectives of Vision 2020: The Right to Sight. Going by the current initiatives and innovation that is apparent in the sector, it is possible to meet the objective by the year 2020.