| ORIGINAL ARTICLE |
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| Year : 2012 | Volume
: 5
| Issue : 2 | Page : 97-102 |
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Comparison between Humphrey Field Analyzer and Micro Perimeter 1 in normal and glaucoma subjects
Vineet Ratra, Dhanashree Ratra, Muneeswar Gupta, K Vaitheeswaran
Medical Research Foundation, Sankara Nethralaya, Chennai, India
Correspondence Address:
Vineet Ratra
Senior Consultant and Incharge, Navasuja Sankara Nethralaya, 73, Venkata Krishna Road, RA Puram, Chennai-600028
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0974-620X.99372
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Purpose: To determine the correlation between fundus perimetry with Micro Perimeter 1 (MP1) and conventional automated static threshold perimetry using the Humphrey Field Analyzer (HFA) in healthy individuals and in subjects with glaucoma.
Materials and Methods: In this study, we enrolled 45 eyes with glaucoma and 21 eyes of age-matched, healthy individuals. All subjects underwent complete ophthalmic examination. Differential light sensitivity was measured at 21 corresponding points in a rectangular test grid in both MP1 and HFA. Similar examination settings were used with Goldmann III stimulus, stimulus presentation time of 200 ms, and white background illumination (1.27 cd/m 2 ). Statistical analysis was done with the SPSS 14 using linear regression and independent t-test.
Results: The mean light thresholds of 21 matching points in control group with MP1 and HFA were 14.97 ± 2.64 dB and 30.90 ± 2.08 dB, respectively. In subjects with glaucoma, the mean values were MP1: 11.73 ± 4.36 dB and HFA: 27.96 ± 5.41 dB. Mean difference of light thresholds among the two instruments was 15.86 ± 3.25 dB in normal subjects (P < 0.001) and 16.22 ± 2.77 dB in glaucoma subjects (P < 0.001). Pearson correlation analysis of the HFA and MP1 results for each test point location in both cases and control subjects showed significant positive correlation (controls, r = 0.439, P = 0.047; glaucoma subjects, r = 0.812, P < 0.001). There was no difference between nasal and temporal points but a slight vertical asymmetry was observed with MP1.
Conclusion: There are significant and reproducible differences in the differential light threshold in MP1 and HFA in both normal and glaucoma subjects. We found a correction factor of 17.271 for comparison of MP1 with HFA. MP1 appeared to be more sensitive in predicting loss in glaucoma. |
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