Goal & Scope

 Project Motivation: 

We have chosen to conduct a Life Cycle Assessment (LCA) on eyeglasses due to their widespread use in daily life among Americans. According to the Vision Council’s December 2021 VisionWatch Vision Correction and Frame reports, approximately 63.7% of American adults wore Rx prescription glasses in 2021(Vision Council, 2021). Given the significant portion of the population relying on eyeglasses, we found this product to be compelling for an LCA. 

 Project Goals: 

Our goals are to understand the current impacts of eyeglasses throughout their entire life cycle. Additionally, we are hoping to explore potential opportunities to reduce eyeglasses environmental impact, as even small improvements can contribute to a more sustainable product. We are hoping to answer the following questions: What is the current life cycle of a pair of Warby Parker eyeglasses? What are the major avenues in manufacturing and production that currently have the highest impact? Is the current process already sustainable? Are there ways we can find alternatives or change this process to be more sustainable?

 Project Audience: 

Our intended audience for this LCA falls into two main categories: external and internal stakeholders. First, the external stakeholders include consumers and policymakers. Consumers who are more conscious of their purchases and environmental impact may be interested in understanding the origins of the products they buy and their effects on the planet. Similarly, policymakers and regulatory bodies may find value in the LCA to assess compliance with existing standards or determine whether updates to regulations are necessary. Second, internal stakeholders encompass everyone involved in the production and manufacturing process, including development teams, sustainability professionals, and supply chain managers. The internal stakeholders will find the LCA provides valuable insights from both a cost-saving and impact-reduction standpoint. By analyzing the entire life cycle, from raw materials to end-of-life, the LCA can identify opportunities to optimize materials, improve manufacturing processes, enhance transportation efficiency, and increase recycling efforts. Overall, this assessment serves many audiences and contains varied applications.

Product Function:

The product our group is analyzing for this Life Cycle Assessment is a pair of glasses. This pair of glasses was made by the company Warby Parker. The function of the glasses is to correct vision. The components of this product include: two plastic lenses, a metal interior rod at the temples, plastic frames, metal screws, coating, and pigment. The product was carefully disassembled, as pictured in the image above. 

Lifecycle Phases: 

Warby Parker Cradle-Grave Initial Flowchart can be seen below: (Ace, Tate & De Lange, 2013) 

We have included all manufacturing/production and transportation steps that go into the glasses. This is excluding the extraction and processing of raw materials (Ace & Tate, 2013). 

Manufacturing/production and Transportation includes:

• Material Processing: Acetate is mixed, molded, and pressed into solid blocks.

• Frame Production: CNC machines cut frames, which are then polished in tumbling barrels filled with wood chips and beeswax.

• Lens Manufacturing: Polycarbonate lenses are treated with anti-reflective and scratch-resistant coatings, then precisely cut and mounted into frames.

• Assembly & Quality Control: Frames are hand assembled, screws are inserted, and hinges are tested for durability before final inspection

• Supply Chain Logistics: Cellulose Acetate sourced from Italy, Beeswax sourced from Germany, Manufacturing & Assembly facilities located in Sloatsburg, New York, and Las Vegas, Nevada

We have excluded the upstream resource extraction processes, avoiding highly detailed analysis of mining, drilling, or harvesting beyond first-stage processing. We also are excluding the environmental impact of warehousing, retail stores, and consumer travel to purchase glasses along with reuse scenarios outside standard disposal methods. In addition we are excluding personal cleaning/maintenance, and the impact of lens wipes or cleaning solutions.

System Boundaries

• • Cradle-to-grave LCA

    • Raw-material extraction: Cellulose acetate, steel, lens, packaging 

    • Transport: to manufacture, warehouse, across seas, retail/customer 

    • Manufacturing: Mixing, melting, molding 

    • Warehouse: storage, packaging

    • End of Life: Landfill, lens/frame recycling      

• Geographical considerations

  • Some geographical considerations include where our materials are sourced from, where everything is manufactured and assembled and lastly where the product is being distributed too. Materials like cellulose acetate are sourced from Italy, Beeswax used for polishing from Germany, and Titanium used as screws are sourced primarily from China. All the manufacturing and assembly is in New York and Nevada and this product gets distributed both domestically and internationally.

• Time boundaries

  • Warby Parker was founded in 2010 and we don’t have specifics on the production date for the model we are conducting an LCA on. Therefore, we will set our time boundary within the past 5–10 years (2015–2025) to ensure data reflects modern manufacturing practices, material sourcing, and transportation impacts. 

• Foreground 

  • Our foreground process will include frame and lens manufacturing, polishing, assembly, quality checks, along with transportation of materials needed for manufacturing. Our background data that we will pull from the LCI database include energy supply and transport emissions of product distribution.

Functional Unit: 

The functional unit of the Warby Parker eyeglasses is using one pair of eyeglasses to provide vision correction for one year. This functional unit is based on research according to Warby Parker, who says that Americans should get their eyes checked every one to two years (Srednick, 2024). This functional unit has both a function and a timeframe. The function of the eyeglasses is to help correct vision problems and maintain optimal clarity for its entire lifespan. The timeframe of the functional unit is one year because that is the typical daily usage before the user must get their eyes checked. This functional unit is assuming that the glasses will be durable and will not significantly degrade or break within that year's time span.

Assumptions

• Lifespan of glasses:

  • Assumption: The lifespan of glasses is 1 year before replacement.

  • Justification: Based on research according to Warby Parker, Americans should get their eyes checked every one to two years (Srednick, 2024). Therefore, if they are prescribed corrective glasses, we assume they will get glasses during this timeframe. 

• Frequency of Use:

  • Assumption: Prescription glasses are worn all day, or about 12 hours a day. Justification: According to Oscar Wylee, it is necessary to wear prescription glasses as often as prescribed by your optometrist. Typical corrections are for daily wear (Oscar, n.d.)

• Recycling Rate of Materials:

  • Assumption: 

    • Titanium Screws: Nearly 60% recycled due to high recyclability of titanium (Circular Economy, 2023)

    • Polycarbonate Lenses: Less than 10% recycled, as recycling polycarbonate is costly (Circular Economy, 2023)

    • Cellulose Acetate Frames: Not recycled, as acetate recycling infrastructure is very limited. 

  • Justification: Titanium is oftenly recycled in medical and aerospace industries. Polycarbonate and acetate are costly and very much difficult to process.

• Discussion of Limitations:

  • Consumer Behavior Variability: Recycling rates, lifespan, and usage frequency differ among users, leading to potential overestimation or underestimation of impacts. 

  • Lack of primary data: Manufacturer specific energy consumption and emissions data are not available, requiring reliance on industry averages.

  • Material processing unknowns: Some coatings and additives in polycarbonate lenses and cellulose acetate frames may influence degradation rates and toxicity, but data is limited

  • End-of-life challenges: Limited infrastructure for eyeglass recycling means that disposal pathways are uncertain.