More Time in Range Lowers Eye Disease Risk in Type 1 Diabetes

What Was Studied and Why It Matters

Diabetic retinopathy — damage to the tiny blood vessels in the eye — is one of the most feared complications of Type 1 diabetes and a leading cause of preventable blindness. Researchers from a 2026 study published in The Journal of Clinical Endocrinology and Metabolism wanted to know whether a newer glucose measurement called Time in Range (TIR) could predict who develops eye disease — and whether improving it could actually prevent blindness.

TIR measures the percentage of the day a person's glucose readings stay within a healthy window of 70–180 mg/dL. Unlike the traditional HbA1c blood test, which gives a single average number, TIR — tracked by continuous glucose monitors (CGMs) — shows the full picture of daily glucose patterns.

What the Researchers Found

The team analyzed linked CGM data and health records from 161 adults with Type 1 diabetes, following them over time to see who developed retinopathy. Here's what stood out:

• Every 10% improvement in TIR was linked to a 12% lower risk of retinopathy getting worse.
• People who maintained a TIR of 70% (meaning glucose was in range about 17 hours a day) compared to those at 40% TIR had an estimated 39 fewer cases of blindness per 1,000 people over their lifetime.
• Higher TIR was also associated with $2,581 in lower healthcare costs per person and a gain of 0.13 quality-adjusted life years — a meaningful improvement in healthy living time.

What This Means for Real Patients

This study delivers an encouraging and practical message: the more time you spend with your glucose in a healthy range, the better protected your eyes are — and it doesn't have to be perfect to matter. Even modest improvements in TIR add up to real benefits over time.

If you use a CGM device, your TIR percentage is one of the most important numbers on your dashboard. Talk to your care team about what your target TIR should be and what adjustments to insulin timing, diet, or activity might help you hit it more consistently.

Staying stocked with reliable CGM supplies is a key part of making this work day to day. MDS Diabetes carries a wide range of CGM sensors, transmitters, and accessories to help you monitor continuously without interruption — because gaps in data can mean gaps in protection.

The Economic Case Is Clear Too

Beyond health outcomes, the cost savings are significant. Preventing retinopathy and blindness through better glucose management isn't just better for patients — it reduces the burden on the entire healthcare system. Investing in good CGM technology and supplies today can save thousands of dollars in future treatment costs.

Bottom Line

Spending more of your day with glucose levels between 70–180 mg/dL measurably reduces your risk of diabetic eye disease and blindness. A 10% bump in your Time in Range could make a real difference in your long-term vision — and your wallet. If you use a CGM, check your TIR regularly, discuss your goals with your doctor, and make sure you always have the supplies you need. MDS Diabetes is here to help you stay equipped and in range.