查看購物車
  • English
  • Japanese
  • Korean
封面
市場調查報告書
商品編碼
1963922

人工水晶體市場－全球產業規模、佔有率、趨勢、機會和預測：按產品、最終用戶、地區和競爭對手分類，2021-2031年

Intraocular Lens Market - Global Industry Size, Share, Trends, Opportunity, and Forecast, Segmented By Product, By End user, By Region & Competition, 2021-2031F
出版日期: | 出版商: TechSci Research | 英文 185 Pages | 商品交期: 2-3個工作天內

價格

We offer 8 hour analyst time for an additional research. Please contact us for the details.

簡介目錄

全球人工水晶體市場預計將從 2025 年的 47.9 億美元成長到 2031 年的 62.4 億美元，複合年成長率達到 4.51%。

這些人工植入旨在白內障手術中替代眼球的天然水晶體，對於恢復清晰視力至關重要。其成長主要受全球人口快速老化驅動，而人口老化又與白內障患病率上升以及對有效視力恢復治療需求激增直接相關。此外，患者對無眼鏡視力恢復的偏好也發生了顯著變化，推動了具有多焦點功能的先進晶狀體技術的應用。為了佐證人們對更佳視覺效果的需求，歐洲屈光和屈光手術學會報告稱，在其調查的會員中，2024年同時進行視力調節的人工水晶體植入率達到了16%。

市場概覽
預測期 2027-2031
市場規模：2025年 47.9億美元
市場規模：2031年 62.4億美元
複合年成長率：2026-2031年 4.51%
成長最快的細分市場 多焦點人工水晶體
最大的市場 北美洲

儘管前景光明，但經濟壁壘仍是市場擴張的主要障礙。除了高階隱形眼鏡價格昂貴之外，不同醫療體系報銷政策的不一致也導致許多患者無法獲得這些先進的治療方案。因此，許多患者只能選擇標準單焦點隱形眼鏡，這限制了高階市場的獲利能力，尤其是在價格敏感型地區。

市場促進因素

白內障和老齡化眼科疾病的日益普遍是推動市場成長的主要催化劑，全球範圍內的手術量也因此大幅增加。隨著人口老化，水晶體混濁的發生率不斷上升，需要進行擴充性且頻繁的修復手術來預防視力喪失。這一人口趨勢直接支撐了主要醫療設備製造商的持續收入成長，凸顯了疾病負擔與市場需求之間的關聯性。例如，愛爾康公司在2025年2月發布的年度報告中指出，其2024會計年度全年手術相關淨銷售額達到55億美元，反映了全球對眼科手術產品的旺盛需求。同樣，卡爾蔡司醫療技術公司在2025年12月宣布，其眼科策略業務部門在2024/25會計年度的收入達到17.2億歐元，進一步證明了該行業的龐大規模。

第二個關鍵促進因素是高階和多焦點人工水晶體（IOL）的技術進步，這使得價值的焦點從單純的手術次數轉向更卓越的視覺效果。外科醫生和患者都越來越傾向於選擇超越單焦點晶狀體的功能，這種晶狀體可以消除對眼鏡的依賴，並矯正老花眼和散光。這一趨勢推動了景深擴展（EDOF）和三焦點技術的應用，從而導致更高的價格和更多元化的收入來源。例如，強生公司在2025年1月發布的報告顯示，其醫療技術部門2024年第四季的視覺相關產品銷售額成長了7.9%。 TECNIS PureSee和Eyhance等人工水晶體的商業性成功尤其提振了手術領域的表現。

市場挑戰

全球人工水晶體市場在很大程度上受到持續存在的經濟障礙的限制，這些障礙限制了患者獲得先進技術的機會。儘管臨床上對無需佩戴眼鏡的多焦點和高階人工水晶體有著明顯的需求，但這些植入相關的高昂自付費用卻讓相當一部分潛在患者望而卻步。在許多醫療保健系統中，保險報銷模式僅涵蓋標準單焦點人工水晶體，迫使患者承擔升級到高階人工水晶體的全部費用。這種價格差異造成了市場兩極化，在價格敏感的地區，低利潤的基礎產品佔據了主導地位，有效地抑制了該行業的潛在價值成長。

此外，白內障手術報銷率的波動加劇了這項挑戰，擠壓了眼科診所的營運利潤，降低了他們推薦高階手術方案的意願。 2024年，美國眼科學會宣布，美國醫療保險和醫療補助服務中心（CMS）已將醫生報銷比例降低了3.37%。報銷資金的減少給手術提供者帶來了額外的經濟負擔，使他們越來越難以維持額外的諮詢時間和行政資源，從而難以向患者解釋和提供高成本的高階晶體技術，這直接阻礙了市場收入的成長。

市場趨勢

術後光可調人工晶體（LAL）系統的商業化正在從根本上改變屈光矯正的精準度，解決了人工晶體有效植入和癒合反應的不確定性。與需要精確術前預測的固定式高階人工晶體不同，這些系統允許外科醫生使用紫外線照射治療來調節植入人工晶體的屈光。這不僅可以矯正殘餘屈光不正，還能提供每位患者個人化的視覺效果。這項技術正迅速受到醫療機構的青睞，這些機構希望降低意外屈光不正的風險並儘量減少再次手術。 RxSight公司截至2025年2月的會計年度財務數據顯示，2024年全年銷售額將達到1.399億美元，年增57%，凸顯了臨床對這項可調可用技術的日益成長的需求。

同時，用於矯正高度近視的有晶體眼人工晶體（Phakic IOL）市場的擴張表明，對於不適合接受角膜雷射手術的年輕患者，屈光矯正方案正朝著基於晶體的方案轉變。這一趨勢的特徵是可植入式膠原蛋白晶體（ICL）的使用日益增加。 ICL是一種可逆的手術方式，可以取代LASIK和PRK，在矯正嚴重屈光不正的同時保留眼球的天然晶狀體。在傳統重點區域之外，ICL市場成長尤其強勁，凸顯了此方法作為主要屈光矯正方案的有效性。根據STAAR Surgical發布的2025會計年度報告，除中國以外，ICL（可植入式膠原蛋白晶體）的季度銷售額達到3,950萬美元，較去年同期成長17%。這表明該治療方法在全球範圍內的接受度正在不斷提高。

目錄

第1章概述

第2章：調查方法

第3章執行摘要

第4章：客戶心聲

第5章：全球人工水晶體市場展望

  • 市場規模及預測
    • 按金額
  • 市佔率及預測
    • 產品類別（單人工水晶體、多焦點人工水晶體、散光人工水晶體、IOCT人工水晶體）
    • 依最終使用者（醫院/診所、門診中心、其他）分類
    • 按地區
    • 按公司（2025 年）
  • 市場地圖

第6章：北美人工水晶體市場展望

  • 市場規模及預測
  • 市佔率及預測
  • 北美洲：國別分析
    • 美國
    • 加拿大
    • 墨西哥

第7章：歐洲人工水晶體市場展望

  • 市場規模及預測
  • 市佔率及預測
  • 歐洲：國別分析
    • 德國
    • 法國
    • 英國
    • 義大利
    • 西班牙

第8章：亞太地區人工水晶體市場展望

  • 市場規模及預測
  • 市佔率及預測
  • 亞太地區：國別分析
    • 中國
    • 印度
    • 日本
    • 韓國
    • 澳洲

第9章：中東和非洲人工水晶體市場展望

  • 市場規模及預測
  • 市佔率及預測
  • 中東與非洲：國別分析
    • 沙烏地阿拉伯
    • 阿拉伯聯合大公國
    • 南非

第10章：南美洲人工水晶體市場展望

  • 市場規模及預測
  • 市佔率及預測
  • 南美洲：國別分析
    • 巴西
    • 哥倫比亞
    • 阿根廷

第11章 市場動態

  • 促進因素
  • 任務

第12章 市場趨勢與發展

  • 併購
  • 產品發布
  • 近期趨勢

第13章：全球人工水晶體市場：SWOT分析

第14章：波特五力分析

  • 產業競爭
  • 新進入者的潛力
  • 供應商的議價能力
  • 顧客權力
  • 替代品的威脅

第15章 競爭格局

  • Alcon, Inc.
  • Johnson and Johnson
  • Bausch & Lomb Incorporated
  • Carl Zeiss Meditec AG
  • Rayner Group
  • EyeKon Medical, Inc.
  • Lenstec, Inc.
  • HumanOptics AG
  • STAAR Surgical Company
  • Hoya Corporation

第16章 策略建議

第17章：關於研究公司及免責聲明

簡介目錄
Product Code: 19354

The Global Intraocular Lens Market is projected to expand from USD 4.79 Billion in 2025 to USD 6.24 Billion by 2031, achieving a compound annual growth rate of 4.51%. Designed to replace the natural lens of the eye, typically during cataract surgery, these artificial implants are essential for restoring clear vision. This growth is primarily fueled by a rapidly aging global demographic, which directly correlates with a higher prevalence of cataracts and a surging need for effective restorative interventions. Furthermore, there is a noticeable shift in patient preference toward achieving spectacle independence, driving the uptake of advanced lens technologies with multifocal features. Highlighting this demand for superior visual outcomes, the European Society of Cataract and Refractive Surgeons reported a 16% conversion rate for simultaneous vision intraocular lenses among surveyed members in 2024.

Market Overview
Forecast Period2027-2031
Market Size 2025USD 4.79 Billion
Market Size 2031USD 6.24 Billion
CAGR 2026-20314.51%
Fastest Growing SegmentMultifocal intraocular lens
Largest MarketNorth America

Despite this promising outlook, economic hurdles continue to pose a major obstacle to widespread market development. The high expense associated with premium lenses, combined with uneven reimbursement policies across various healthcare frameworks, often restricts patient access to these sophisticated treatment alternatives. As a result, a significant number of individuals are confined to standard monofocal lenses, a factor that limits the revenue potential of the premium segment, particularly in price-sensitive regions.

Market Driver

The escalating prevalence of cataracts and age-related eye conditions acts as the primary catalyst for market growth, necessitating a substantial global increase in surgical volumes. As the elderly population grows, the frequency of lens opacification increases, requiring scalable and frequent restorative procedures to avert vision loss. This demographic trend directly supports sustained financial gains for leading device manufacturers, confirming the link between disease burden and market demand. For instance, Alcon reported in its February 2025 Annual Report that surgical net sales hit $5.5 billion for the full year 2024, reflecting strong global demand for ophthalmic surgical products. Similarly, Carl Zeiss Meditec AG announced in December 2025 that its Ophthalmology Strategic Business Unit achieved revenues of €1.72 billion for the 2024/25 fiscal year, further demonstrating the sector's vast scale.

A second pivotal driver is the technological progression in premium and multifocal intraocular lenses (IOLs), which shifts the value focus from mere procedural volume to superior visual results. Both surgeons and patients are increasingly favoring lenses that provide spectacle independence and correct conditions like presbyopia or astigmatism, moving beyond basic monofocal solutions. This preference fuels the adoption of Extended Depth of Focus (EDOF) and trifocal technologies, which command higher prices and diversify revenue streams. Illustrating this trend, Johnson & Johnson reported in January 2025 that vision sales within its MedTech segment rose by 7.9% in the fourth quarter of 2024, with surgical performance specifically boosted by the commercial success of innovations like the TECNIS PureSee and Eyhance intraocular lenses.

Market Challenge

The expansion of the Global Intraocular Lens Market is significantly constrained by persistent economic barriers that limit patient access to advanced technologies. While there is a clear clinical demand for multifocal and premium lenses that facilitate spectacle independence, the substantial out-of-pocket costs associated with these implants discourage a large portion of the potential patient base. In many healthcare systems, reimbursement models only cover standard monofocal lenses, leaving patients to cover the entire financial difference for premium upgrades. This price disparity creates a divided market where adoption is heavily skewed toward basic, lower-revenue products in price-sensitive areas, effectively capping the industry's potential value growth.

Additionally, fluctuations in reimbursement rates for cataract procedures exacerbate this challenge by tightening the operational margins of ophthalmic practices, thereby disincentivizing the promotion of premium options. In 2024, the American Academy of Ophthalmology noted that the Centers for Medicare & Medicaid Services implemented a 3.37% reduction in the physician fee schedule conversion factor. This decline in reimbursement funding places further financial strain on surgical providers, making it increasingly difficult to sustain the extra chair time and administrative resources required to educate patients on and deliver high-cost premium lens technologies, directly stalling market revenue growth.

Market Trends

The commercialization of Post-Operative Light-Adjustable Lens (LAL) Systems is fundamentally transforming the refractive accuracy landscape by addressing the unpredictability of effective lens position and healing responses. Unlike static premium lenses that require precise pre-operative estimation, these systems allow surgeons to modify the lens power after implantation using UV light treatments, thereby correcting residual refractive errors and delivering customized visual profiles. This capability has driven rapid uptake among practices seeking to mitigate the risk of refractive surprises and minimize enhancement procedures. According to RxSight, Inc.'s February 2025 financial results, full-year 2024 revenue reached $139.9 million, marking a 57% increase over the previous year, highlighting the surging clinical demand for this adjustable technology.

Simultaneously, the expansion of the Phakic IOL Market for High Myopia Correction represents a strategic shift toward lens-based refractive solutions for younger patients who are unsuitable for corneal laser procedures. This trend is characterized by the increasing utilization of implantable collamer lenses that preserve the eye's natural crystalline lens while correcting severe refractive errors, offering a reversible alternative to LASIK or PRK. Market growth is particularly robust in regions where adoption is diversifying beyond traditional strongholds, validating the modality as a primary option for refractive correction. According to STAAR Surgical's February 2025 report, Implantable Collamer Lens (ICL) sales excluding the Chinese market reached $39.5 million for the quarter, an increase of 17% compared to the prior year period, evidencing the widening global acceptance of this therapeutic class.

Key Market Players

  • Alcon, Inc.
  • Johnson and Johnson
  • Bausch & Lomb Incorporated
  • Carl Zeiss Meditec AG
  • Rayner Group
  • EyeKon Medical, Inc.
  • Lenstec, Inc.
  • HumanOptics AG
  • STAAR Surgical Company
  • Hoya Corporation

Report Scope

In this report, the Global Intraocular Lens Market has been segmented into the following categories, in addition to the industry trends which have also been detailed below:

Intraocular Lens Market, By Product

  • Monofocal Intraocular Lens
  • Multifocal Intraocular Lens
  • Toric Intraocular Lens
  • Accommodative Intraocular Lens

Intraocular Lens Market, By End user

  • Hospitals & Clinics
  • Ambulatory Care Centers
  • Others

Intraocular Lens Market, By Region

  • North America
    • United States
    • Canada
    • Mexico
  • Europe
    • France
    • United Kingdom
    • Italy
    • Germany
    • Spain
  • Asia Pacific
    • China
    • India
    • Japan
    • Australia
    • South Korea
  • South America
    • Brazil
    • Argentina
    • Colombia
  • Middle East & Africa
    • South Africa
    • Saudi Arabia
    • UAE

Competitive Landscape

Company Profiles: Detailed analysis of the major companies present in the Global Intraocular Lens Market.

Available Customizations:

Global Intraocular Lens Market report with the given market data, TechSci Research offers customizations according to a company's specific needs. The following customization options are available for the report:

Company Information

  • Detailed analysis and profiling of additional market players (up to five).

Table of Contents

1. Product Overview

  • 1.1. Market Definition
  • 1.2. Scope of the Market
    • 1.2.1. Markets Covered
    • 1.2.2. Years Considered for Study
    • 1.2.3. Key Market Segmentations

2. Research Methodology

  • 2.1. Objective of the Study
  • 2.2. Baseline Methodology
  • 2.3. Key Industry Partners
  • 2.4. Major Association and Secondary Sources
  • 2.5. Forecasting Methodology
  • 2.6. Data Triangulation & Validation
  • 2.7. Assumptions and Limitations

3. Executive Summary

  • 3.1. Overview of the Market
  • 3.2. Overview of Key Market Segmentations
  • 3.3. Overview of Key Market Players
  • 3.4. Overview of Key Regions/Countries
  • 3.5. Overview of Market Drivers, Challenges, Trends

4. Voice of Customer

5. Global Intraocular Lens Market Outlook

  • 5.1. Market Size & Forecast
    • 5.1.1. By Value
  • 5.2. Market Share & Forecast
    • 5.2.1. By Product (Monofocal Intraocular Lens, Multifocal Intraocular Lens, Toric Intraocular Lens, Accommodative Intraocular Lens)
    • 5.2.2. By End user (Hospitals & Clinics, Ambulatory Care Centers, Others)
    • 5.2.3. By Region
    • 5.2.4. By Company (2025)
  • 5.3. Market Map

6. North America Intraocular Lens Market Outlook

  • 6.1. Market Size & Forecast
    • 6.1.1. By Value
  • 6.2. Market Share & Forecast
    • 6.2.1. By Product
    • 6.2.2. By End user
    • 6.2.3. By Country
  • 6.3. North America: Country Analysis
    • 6.3.1. United States Intraocular Lens Market Outlook
      • 6.3.1.1. Market Size & Forecast
        • 6.3.1.1.1. By Value
      • 6.3.1.2. Market Share & Forecast
        • 6.3.1.2.1. By Product
        • 6.3.1.2.2. By End user
    • 6.3.2. Canada Intraocular Lens Market Outlook
      • 6.3.2.1. Market Size & Forecast
        • 6.3.2.1.1. By Value
      • 6.3.2.2. Market Share & Forecast
        • 6.3.2.2.1. By Product
        • 6.3.2.2.2. By End user
    • 6.3.3. Mexico Intraocular Lens Market Outlook
      • 6.3.3.1. Market Size & Forecast
        • 6.3.3.1.1. By Value
      • 6.3.3.2. Market Share & Forecast
        • 6.3.3.2.1. By Product
        • 6.3.3.2.2. By End user

7. Europe Intraocular Lens Market Outlook

  • 7.1. Market Size & Forecast
    • 7.1.1. By Value
  • 7.2. Market Share & Forecast
    • 7.2.1. By Product
    • 7.2.2. By End user
    • 7.2.3. By Country
  • 7.3. Europe: Country Analysis
    • 7.3.1. Germany Intraocular Lens Market Outlook
      • 7.3.1.1. Market Size & Forecast
        • 7.3.1.1.1. By Value
      • 7.3.1.2. Market Share & Forecast
        • 7.3.1.2.1. By Product
        • 7.3.1.2.2. By End user
    • 7.3.2. France Intraocular Lens Market Outlook
      • 7.3.2.1. Market Size & Forecast
        • 7.3.2.1.1. By Value
      • 7.3.2.2. Market Share & Forecast
        • 7.3.2.2.1. By Product
        • 7.3.2.2.2. By End user
    • 7.3.3. United Kingdom Intraocular Lens Market Outlook
      • 7.3.3.1. Market Size & Forecast
        • 7.3.3.1.1. By Value
      • 7.3.3.2. Market Share & Forecast
        • 7.3.3.2.1. By Product
        • 7.3.3.2.2. By End user
    • 7.3.4. Italy Intraocular Lens Market Outlook
      • 7.3.4.1. Market Size & Forecast
        • 7.3.4.1.1. By Value
      • 7.3.4.2. Market Share & Forecast
        • 7.3.4.2.1. By Product
        • 7.3.4.2.2. By End user
    • 7.3.5. Spain Intraocular Lens Market Outlook
      • 7.3.5.1. Market Size & Forecast
        • 7.3.5.1.1. By Value
      • 7.3.5.2. Market Share & Forecast
        • 7.3.5.2.1. By Product
        • 7.3.5.2.2. By End user

8. Asia Pacific Intraocular Lens Market Outlook

  • 8.1. Market Size & Forecast
    • 8.1.1. By Value
  • 8.2. Market Share & Forecast
    • 8.2.1. By Product
    • 8.2.2. By End user
    • 8.2.3. By Country
  • 8.3. Asia Pacific: Country Analysis
    • 8.3.1. China Intraocular Lens Market Outlook
      • 8.3.1.1. Market Size & Forecast
        • 8.3.1.1.1. By Value
      • 8.3.1.2. Market Share & Forecast
        • 8.3.1.2.1. By Product
        • 8.3.1.2.2. By End user
    • 8.3.2. India Intraocular Lens Market Outlook
      • 8.3.2.1. Market Size & Forecast
        • 8.3.2.1.1. By Value
      • 8.3.2.2. Market Share & Forecast
        • 8.3.2.2.1. By Product
        • 8.3.2.2.2. By End user
    • 8.3.3. Japan Intraocular Lens Market Outlook
      • 8.3.3.1. Market Size & Forecast
        • 8.3.3.1.1. By Value
      • 8.3.3.2. Market Share & Forecast
        • 8.3.3.2.1. By Product
        • 8.3.3.2.2. By End user
    • 8.3.4. South Korea Intraocular Lens Market Outlook
      • 8.3.4.1. Market Size & Forecast
        • 8.3.4.1.1. By Value
      • 8.3.4.2. Market Share & Forecast
        • 8.3.4.2.1. By Product
        • 8.3.4.2.2. By End user
    • 8.3.5. Australia Intraocular Lens Market Outlook
      • 8.3.5.1. Market Size & Forecast
        • 8.3.5.1.1. By Value
      • 8.3.5.2. Market Share & Forecast
        • 8.3.5.2.1. By Product
        • 8.3.5.2.2. By End user

9. Middle East & Africa Intraocular Lens Market Outlook

  • 9.1. Market Size & Forecast
    • 9.1.1. By Value
  • 9.2. Market Share & Forecast
    • 9.2.1. By Product
    • 9.2.2. By End user
    • 9.2.3. By Country
  • 9.3. Middle East & Africa: Country Analysis
    • 9.3.1. Saudi Arabia Intraocular Lens Market Outlook
      • 9.3.1.1. Market Size & Forecast
        • 9.3.1.1.1. By Value
      • 9.3.1.2. Market Share & Forecast
        • 9.3.1.2.1. By Product
        • 9.3.1.2.2. By End user
    • 9.3.2. UAE Intraocular Lens Market Outlook
      • 9.3.2.1. Market Size & Forecast
        • 9.3.2.1.1. By Value
      • 9.3.2.2. Market Share & Forecast
        • 9.3.2.2.1. By Product
        • 9.3.2.2.2. By End user
    • 9.3.3. South Africa Intraocular Lens Market Outlook
      • 9.3.3.1. Market Size & Forecast
        • 9.3.3.1.1. By Value
      • 9.3.3.2. Market Share & Forecast
        • 9.3.3.2.1. By Product
        • 9.3.3.2.2. By End user

10. South America Intraocular Lens Market Outlook

  • 10.1. Market Size & Forecast
    • 10.1.1. By Value
  • 10.2. Market Share & Forecast
    • 10.2.1. By Product
    • 10.2.2. By End user
    • 10.2.3. By Country
  • 10.3. South America: Country Analysis
    • 10.3.1. Brazil Intraocular Lens Market Outlook
      • 10.3.1.1. Market Size & Forecast
        • 10.3.1.1.1. By Value
      • 10.3.1.2. Market Share & Forecast
        • 10.3.1.2.1. By Product
        • 10.3.1.2.2. By End user
    • 10.3.2. Colombia Intraocular Lens Market Outlook
      • 10.3.2.1. Market Size & Forecast
        • 10.3.2.1.1. By Value
      • 10.3.2.2. Market Share & Forecast
        • 10.3.2.2.1. By Product
        • 10.3.2.2.2. By End user
    • 10.3.3. Argentina Intraocular Lens Market Outlook
      • 10.3.3.1. Market Size & Forecast
        • 10.3.3.1.1. By Value
      • 10.3.3.2. Market Share & Forecast
        • 10.3.3.2.1. By Product
        • 10.3.3.2.2. By End user

11. Market Dynamics

  • 11.1. Drivers
  • 11.2. Challenges

12. Market Trends & Developments

  • 12.1. Merger & Acquisition (If Any)
  • 12.2. Product Launches (If Any)
  • 12.3. Recent Developments

13. Global Intraocular Lens Market: SWOT Analysis

14. Porter's Five Forces Analysis

  • 14.1. Competition in the Industry
  • 14.2. Potential of New Entrants
  • 14.3. Power of Suppliers
  • 14.4. Power of Customers
  • 14.5. Threat of Substitute Products

15. Competitive Landscape

  • 15.1. Alcon, Inc.
    • 15.1.1. Business Overview
    • 15.1.2. Products & Services
    • 15.1.3. Recent Developments
    • 15.1.4. Key Personnel
    • 15.1.5. SWOT Analysis
  • 15.2. Johnson and Johnson
  • 15.3. Bausch & Lomb Incorporated
  • 15.4. Carl Zeiss Meditec AG
  • 15.5. Rayner Group
  • 15.6. EyeKon Medical, Inc.
  • 15.7. Lenstec, Inc.
  • 15.8. HumanOptics AG
  • 15.9. STAAR Surgical Company
  • 15.10. Hoya Corporation

16. Strategic Recommendations

17. About Us & Disclaimer