Abstract
Purpose :
Glaucoma is a leading cause of blindness. Myopia and glaucoma are often associated and myopia is thought to predispose to glaucoma. With increase in myopia prevalence globally, glaucoma in myopia assumes greater importance. It was the purpose to understand the features of this condition in India.
Methods :
173 subjects with POAG were studied. The mean axial length in Central India in a population based study was found to be 22.6 ± 0.91mm. Based on this, three groups were created. Those with an axial length of <=23.5, (< mean +1SD), >23.5mm ( > mean +1 SD) and with >24.4 mm(> mean + 2SD). Group 1 included 53 subjects ( 105 eyes, mean AL 22.77 ± 0.54), Group 2 had 74 subjects (148 eyes, mean AL 24.73 ± 1.31) and Group 3 of 36 subjects ( 71 eyes, mean AL 25.64 ± 1.40). All subjects underwent an ophthalmic evaluation which included biometry, IOP, central corneal thickness and spectral domain OCT to assess the RNFLT and the minimum rim width.
Results :
For Group 1-3, mean age was ( 62.22 ± 13.61; 57.66 ± 12.6 and 55.73 ± 12.19 yrs). BCVA values were (0.73 ± 0.31; 0.75 ± 0.28 and 0.78 ± 0.27), IOP was (19.05 ± 7.13; 18.37 ± 6.1 and 19.51 ± 6.43), CCT was ( 534.18 ± 31.99; 527 ± 33.91 and 525.57 ± 36.09), Axial length was ( 22.76 ± 0.55; 24.73 ± 1.31 and 25.64 ± 1.40) BMO area was (1.98 ± 0.40; 2.12 ± 0.60 and 2.10 ± 0.67) respectively. The global minimum rim width percentile values were ( 2.85 ± 5.02; 3.6 ± 6.99 and 3.12 ± 5.41). Global RNFLT percentile values were (2.40 ± 4.07 ;4.51 ± 8.41 and 4.35 ± 9.30). In Group 1, 2 and 3 - Parapapillary atrophy was absent in ( 33.3%; 36% and 14%). Beta zone alone was present in (56.4%; 53.4% and 35%). Beta and Gamma both Zone were present in ( 6.7%; 12.8% and 15.5%) and Gamma zone alone was present in (1.9%; 8.8% and 14.1%). Total percentage of eyes with Beta zone and Gamma zone in Group 1 was 61 and 8.6; Group 2 was 66.2 and 21.6 and Group 3 was 64.8 and 29.6. Increasing axial length was correlated with younger age in Group 2 and Group 3 ( P <0.001;r=-0.311 and P<0.001;r=-0.429) but not in Group 1 (P0.892;r=0.13).
Conclusions :
There was significant RNFL and MRW loss in this group of subjects. Increasing axial length was associated with subjects of a younger age, indicating that myopes may be susceptible to developing glaucoma earlier. The presence of gamma zone was increased with increasing axial length. Beta and Gamma zone may be associated together in glaucoma in myopia.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.