OBJECTIVE

To compare the frequency and severity of color vision defects between diabetes mellitus (DM) patients without retinopathy and those with mild non-proliferative diabetic retinopathy (NPDR), and to evaluate the relationship between these color vision defects and capillary blood glucose (CBG) levels.

METHODS

This was a cross-sectional, hospital-based study conducted over a seven-month period at the Ophthalmology Outpatient Department of Cardinal Santos Medical Center. Thirty-five (35) DM patients (70 eyes) aged 50 to 75 years with best-corrected visual acuity of ≥20/50 and no more than mild NPDR were included. Patients with moderate or severe NPDR, macular edema, optic nerve pathology, or significant cataracts were excluded. All participants underwent visual acuity testing, fundus examination, and color vision assessment using the Ishihara pseudoisochromatic plates and Farnsworth D-15 tests conducted under standardized lighting conditions. CBG was measured using the finger-prick method. Main outcome measures included the proportion and type of color vision defects, their association with DR classification, and CBG levels. Statistical analyses included descriptive statistics, the Fisher exact test, the Mann-Whitney U test for the Farnsworth D-15 Color Confusion Index (CCI), and Spearman correlation between CBG and CCI.

RESULTS

Tritan-type defects were the most common, accounting for 36.2%. Color vision defects were observed in 91.3% (64 eyes) of patients with no DR, while defects were seen in all eyes (100%) with mild NPDR (5 eyes). However, this difference was not statistically significant (p = 1.000). There was no significant correlation between CBG levels and color vision scores. Mean CCI scores were similar between groups (p = 0.394), indicating no substantial difference in defect severity.

CONCLUSIONS

Color vision defects may be more prevalent in early NPDR compared to no DR, but this difference was not significant in this sample. No correlation was found between CBG levels and color vision performance. Color vision testing may serve as a useful adjunctive screening tool for early diabetic retinal changes; however, further studies with larger sample sizes are necessary.

Human ; Color Vision Defects ; Diabetic Retinopathy

Objective: To compare the predictability of flap thickness, visual and refractive outcomes, and higher order aberrations in eyes that underwent myopic LASIK using either a Technolas femtosecond laser or a Zyoptix XP mechanical microkeratome for flap creation. Methods: The study involved a total of 44 eyes of 22 patients who underwent LASIK. Flap creation was randomized to using the Technolas femtosecond laser in one eye and Zyoptix XP microkeratome in the contralateral eye. Flap thickness was measured intraoperatively using ultrasonic pachymetry and postoperatively using the Visante ASOCT. Refractive outcome, visual acuity (VA), higher order aberrations, and contrast sensitivity were compared between the two groups. Results: Twenty-two patients had LASIK for myopia or myopic astigmatism. Using ultrasonic pachymetry intraoperatively, the mean flap thickness was 134 (±10) um and 124 (±23) um in the femtosecond (FS) and microkeratome (MK) groups respectively. Comparing the deviation of the actual from the intended flap thickness, the FS group had statistically lower standard deviation compared to the MK group (p=0.04). Using the AS-OCT, the mean flap thickness at 3 months postoperatively was 119 (±10.82) um and 123 (±15.77) um in the FS and MK groups respectively. The difference in standard deviation between the two groups did not reach statistical significance (p=0.19). The mean spherical equivalent at 3 months was -0.45D (±0.42) and -0.13D (±0.16) respectively. Eightynine percent (89%) of eyes had uncorrected VA of 20/20 or better in both groups. All eyes attained best corrected VA of 20/20 or better in both groups. Differences in total higher order aberrations (p=0.09) and contrast sensitivity scores (p=0.47) were not statistically different between the two groups. Conclusion Flap thickness predictability was better using the Technolas femtosecond laser compared to the XP microkeratome blade. Visual and refractive outcomes, higher order aberrations, and contrast sensitivity were comparable between the 2 groups.
Keratomileusis, Laser In Situ ; Lasers, Excimer