Factors affecting reading speed in patients with diabetic macular edema treated with laser photocoagulation.

Elizabeth Pearce,Sobha Sivaprasad,Ngaihang V Chong,Mary Elizabeth Hartnett

doi:10.1371/journal.pone.0105696

Abstract

PurposeTo study the factors that may affect reading speed in patients with diabetic macular edema previously treated with laser photocoagulation.MethodsConsecutive patients with type II diabetes treated with laser photocoagulation for diabetic macular edema (DME) at least twelve months previously, with best corrected visual acuity of better than 65 letters (approximately 20/40) measured with Early Treatment Diabetic Retinopathy Study (ETDRS) charts were included in this study. Patients previously treated with pan-retinal photocoagulation, vitrectomy, intravitreal steroid or anti-VEGF therapy were excluded. Any other ocular co-morbidities that may influence reading ability such as cataract, glaucoma or macular degeneration were also excluded. All patients were refracted by a certified examiner, the following measurements were collected: best corrected visual acuity (BCVA), contrast sensitivity with Pelli-Robson chart, reading speed with MNREAD chart, microperimetry with Nidek MP1, and central subfield thickness with Zeiss spectral domain optical coherent topography.ResultsThe slow reading group had poorer contrast sensitivity (p = 0.001), reduced retinal sensitivity (p = 0.027) and less stable fixation (p = 0.013). Most interestingly the reduced retinal sensitivity findings were driven by the microperimetry value on the right subfield (p = 0.033), (nasal to the fovea in the right eye and temporal to the fovea in the left eye). Multiple linear regression analysis showed that contrast sensitivity is probably the most important factor that affects reading speed (p = 0.001).ConclusionReduced retinal sensitivity after laser treatment is associated with reduced reading speed in patients with diabetic macular edema.

Highlights

Laser photocoagulation remains the first-line treatment for diabetic macular edema (DME) in most patients globally despite the availability of intravitreal steroids and inhibitors of vascular endothelial growth factor (VEGF)
Recent clinical trials show that the visual acuity (VA) outcome of laser photocoagulation for DME is more favourable than the results of the Early Treatment Diabetic Retinopathy Study (ETDRS) [1,2,3]
Patients Consecutive patients with type II diabetes who were treated with macular laser photocoagulation using the modified ETDRS grid treatment without treating the foveal avascularised zone for DME at least twelve months before enrolment with best corrected visual acuity of better than 65 letters measured with Early Treatment Diabetic Retinopathy Study (ETDRS) charts were included in this study

Summary

Introduction

Laser photocoagulation remains the first-line treatment for diabetic macular edema (DME) in most patients globally despite the availability of intravitreal steroids and inhibitors of vascular endothelial growth factor (VEGF). At an individual level, patients are often unhappy with their quality of vision after macular laser photocoagulation despite good recorded distance VA. This applies to reading vision suggesting a discrepancy between distance and reading VA as seen in other macular diseases such as age-related macular degeneration (AMD) and uveitic macular edema [4]. We assessed various factors that may influence reading vision in patients with DME treated with macular laser to better understand the discrepancy between distance and reading vision

Methods

Results

Conclusion